Update CHANGELOG for v1.14.7.

Fetcher is an interface and set of functions for retrieving a
certificate (or chain of certificates) from a spec. It will
determine whether the certificate spec is a file or a server,
and fetch accordingly.

.github/workflows/release.yml

@@ -0,0 +1,35 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+  workflow_dispatch: {}
+
+permissions:
+  contents: write
+
+jobs:
+  goreleaser:
+    name: GoReleaser
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: 'go.mod'
+          cache: true
+
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v6
+        with:
+          distribution: goreleaser
+          version: latest
+          args: release --clean
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -1 +1,5 @@
 .idea
+cmd/cert-bundler/testdata/pkg/*
+# Added by goreleaser init:
+dist/
+cmd/cert-bundler/testdata/bundle/

.golangci.yml

@@ -12,6 +12,12 @@
 
 version: "2"
 
+output:
+  sort-order:
+    - file
+    - linter
+    - severity
+
 issues:
   # Maximum count of issues with the same text.
   # Set to 0 to disable.
@@ -241,11 +247,12 @@ linters:
       # Default: false
       check-type-assertions: true
       exclude-functions:
-        - (*git.wntrmute.dev/kyle/goutils/sbuf.Buffer).Write
+        - (*git.wntrmute.dev/kyle/goutils/dbg.DebugPrinter).Write
         - git.wntrmute.dev/kyle/goutils/lib.Warn
         - git.wntrmute.dev/kyle/goutils/lib.Warnx
         - git.wntrmute.dev/kyle/goutils/lib.Err
         - git.wntrmute.dev/kyle/goutils/lib.Errx
+        - (*git.wntrmute.dev/kyle/goutils/sbuf.Buffer).Write
 
     exhaustive:
       # Program elements to check for exhaustiveness.
@@ -384,6 +391,9 @@ linters:
         - 3
         - 4
         - 8
+        - 24
+        - 30
+        - 365
 
     nakedret:
       # Make an issue if func has more lines of code than this setting, and it has naked returns.
@@ -454,6 +464,8 @@ linters:
         - -QF1008
         # We often explicitly enable old/deprecated ciphers for research.
         - -SA1019
+        # Covered by revive.
+        - -ST1003
 
     usetesting:
       # Enable/disable `os.TempDir()` detections.
@@ -472,6 +484,8 @@ linters:
     rules:
       - path: 'ahash/ahash.go'
         linters: [ staticcheck, gosec ]
+      - path: 'twofactor/.*.go'
+        linters: [ exhaustive, mnd, revive ]
       - path: 'backoff/backoff_test.go'
         linters: [ testpackage ]
       - path: 'dbg/dbg_test.go'

.goreleaser.yaml

@@ -0,0 +1,445 @@
+# This is an example .goreleaser.yml file with some sensible defaults.
+# Make sure to check the documentation at https://goreleaser.com
+
+# The lines below are called `modelines`. See `:help modeline`
+# Feel free to remove those if you don't want/need to use them.
+# yaml-language-server: $schema=https://goreleaser.com/static/schema.json
+# vim: set ts=2 sw=2 tw=0 fo=cnqoj
+
+version: 2
+
+before:
+  hooks:
+    # You may remove this if you don't use go modules.
+    - go mod tidy
+    # you may remove this if you don't need go generate
+    - go generate ./...
+
+builds:
+  - id: atping
+    main: ./cmd/atping/main.go
+    binary: atping
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: ca-signed
+    main: ./cmd/ca-signed/main.go
+    binary: ca-signed
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: cert-bundler
+    main: ./cmd/cert-bundler/main.go
+    binary: cert-bundler
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: cert-revcheck
+    main: ./cmd/cert-revcheck/main.go
+    binary: cert-revcheck
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: certchain
+    main: ./cmd/certchain/main.go
+    binary: certchain
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: certdump
+    main: ./cmd/certdump/main.go
+    binary: certdump
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: certexpiry
+    main: ./cmd/certexpiry/main.go
+    binary: certexpiry
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: certser
+    main: ./cmd/certser/main.go
+    binary: certser
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: certverify
+    main: ./cmd/certverify/main.go
+    binary: certverify
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: clustersh
+    main: ./cmd/clustersh/main.go
+    binary: clustersh
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: cruntar
+    main: ./cmd/cruntar/main.go
+    binary: cruntar
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: csrpubdump
+    main: ./cmd/csrpubdump/main.go
+    binary: csrpubdump
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: data_sync
+    main: ./cmd/data_sync/main.go
+    binary: data_sync
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: diskimg
+    main: ./cmd/diskimg/main.go
+    binary: diskimg
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: dumpbytes
+    main: ./cmd/dumpbytes/main.go
+    binary: dumpbytes
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: eig
+    main: ./cmd/eig/main.go
+    binary: eig
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: fragment
+    main: ./cmd/fragment/main.go
+    binary: fragment
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: host
+    main: ./cmd/host/main.go
+    binary: host
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: jlp
+    main: ./cmd/jlp/main.go
+    binary: jlp
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: kgz
+    main: ./cmd/kgz/main.go
+    binary: kgz
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: minmax
+    main: ./cmd/minmax/main.go
+    binary: minmax
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: parts
+    main: ./cmd/parts/main.go
+    binary: parts
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: pem2bin
+    main: ./cmd/pem2bin/main.go
+    binary: pem2bin
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: pembody
+    main: ./cmd/pembody/main.go
+    binary: pembody
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: pemit
+    main: ./cmd/pemit/main.go
+    binary: pemit
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: readchain
+    main: ./cmd/readchain/main.go
+    binary: readchain
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: renfnv
+    main: ./cmd/renfnv/main.go
+    binary: renfnv
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: rhash
+    main: ./cmd/rhash/main.go
+    binary: rhash
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: rolldie
+    main: ./cmd/rolldie/main.go
+    binary: rolldie
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: showimp
+    main: ./cmd/showimp/main.go
+    binary: showimp
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: ski
+    main: ./cmd/ski/main.go
+    binary: ski
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: sprox
+    main: ./cmd/sprox/main.go
+    binary: sprox
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: stealchain
+    main: ./cmd/stealchain/main.go
+    binary: stealchain
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: stealchain-server
+    main: ./cmd/stealchain-server/main.go
+    binary: stealchain-server
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: subjhash
+    main: ./cmd/subjhash/main.go
+    binary: subjhash
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: tlsinfo
+    main: ./cmd/tlsinfo/main.go
+    binary: tlsinfo
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: tlskeypair
+    main: ./cmd/tlskeypair/main.go
+    binary: tlskeypair
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: utc
+    main: ./cmd/utc/main.go
+    binary: utc
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: yamll
+    main: ./cmd/yamll/main.go
+    binary: yamll
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+  - id: zsearch
+    main: ./cmd/zsearch/main.go
+    binary: zsearch
+    env:
+      - CGO_ENABLED=0
+    goos: [linux, darwin]
+    goarch: [amd64, arm64]
+    ignore:
+      - goos: darwin
+        goarch: amd64
+
+archives:
+  - formats: [tar.gz]
+    # archive filename: name_version_os_arch
+    name_template: >-
+      {{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}{{ if .Arm }}v{{ .Arm }}{{ end }}
+    # use zip for windows archives
+    format_overrides:
+      - goos: windows
+        formats: [zip]
+
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"
+
+release:
+  github:
+    owner: kisom
+    name: goutils
+  footer: >-
+
+    ---
+
+    Released by [GoReleaser](https://github.com/goreleaser/goreleaser).

CHANGELOG

@@ -1,5 +1,176 @@
 CHANGELOG
 
+v1.14.7 - 2025-11-18
+
+Changed:
+- cmd/ca-signed: cleaned up code internally.
+- lib: add base64 encoding to HexEncode.
+- linter fixes.
+
+v1.14.6 - 2025-11-18
+
+Added:
+- certlib: move tlskeypair functions into certlib.
+
+v1.14.5 - 2025-11-18
+
+Changed:
+- certlib/verify: fix a nil-pointer dereference.
+
+v1.14.4 - 2025-11-18
+
+Added:
+- certlib/ski: add support for return certificate SKI.
+- certlib/verify: add support for verifying certificates.
+
+Changed:
+- certlib/dump: moved more functions into the dump package.
+- cmd: many certificate-related commands had their functionality moved into
+  certlib.
+
+v1.14.3 - 2025-11-18
+
+Added:
+- certlib/dump: the certificate dumping functions have been moved into
+  their own package.
+
+Changed:
+- cmd/certdump: refactor out most of the functionality into certlib/dump.
+- cmd/kgz: add extended metadata support.
+
+v1.14.2 - 2025-11-18
+
+Added:
+- lib: add tooling for generating baseline TLS configs.
+
+Changed:
+- cmd: update all commands to allow the use strict TLS configs. Note that
+  many of these tools are intended for debugging broken or insecure TLS
+  systems, and the ability to support insecure TLS configurations is
+  important in this regard.
+
+v1.14.1 - 2025-11-18
+
+Added:
+- build: add missing Dockerfile.
+
+v1.14.0 - 2025-11-18
+
+Added:
+- lib/dialer: introduce proxy-aware dialers and helpers:
+  - NewNetDialer and NewTLSDialer honoring SOCKS5_PROXY, HTTPS_PROXY, HTTP_PROXY
+    (case-insensitive) with precedence SOCKS5 > HTTPS > HTTP.
+  - DialTCP and DialTLS convenience functions; DialTLS performs a TLS handshake
+    and returns a concrete *tls.Conn.
+  - NewHTTPClient: returns a proxy-aware *http.Client. Uses SOCKS5 proxy when
+    configured (disables HTTP(S) proxying to avoid double-proxying); otherwise
+    relies on http.ProxyFromEnvironment (respects HTTP(S)_PROXY and NO_PROXY).
+- build: the releasse-docker.sh builds and pushes the correct Docker images.
+
+Changed:
+- cmd: migrate tools to new proxy-aware helpers where appropriate:
+  - certchain, stealchain, tlsinfo: use lib.DialTLS.
+  - cert-revcheck: use lib.DialTLS for site connects and a proxy-aware
+    HTTP client for OCSP/CRL fetches.
+  - rhash: use proxy-aware HTTP client for downloads.
+- lib/fetch: migrate from certlib/fetch.go to lib/fetch.go and use DialTLS
+  under the hood.
+- go.mod: add golang.org/x/net dependency (for SOCKS5 support) and align x/crypto.
+
+Notes:
+- HTTP(S) proxy CONNECT supports optional basic auth via proxy URL credentials.
+- HTTPS proxies are TLS-wrapped prior to CONNECT.
+- Timeouts apply to TCP connects, proxy handshakes, and TLS handshakes; context
+  cancellation is honored.
+- Some commands retain bespoke dialing (e.g., IPv6-only or unix sockets) and
+  were intentionally left unchanged.
+
+v1.13.6 - 2025-11-18
+
+Changed:
+- build: removing gitea stuff.
+
+v1.13.5 - 2025-11-18
+
+Changed:
+- build: updating goreleaser config.
+
+v1.13.4 - 2025-11-18
+
+Changed:
+- build: updating goreleaser config.
+
+v1.13.3 - 2025-11-18
+
+Added:
+- certlib: introduce `Fetcher` for retrieving certificates.
+- lib: `HexEncode` gains a byte-slice output variant.
+- build: add GoReleaser configuration.
+
+Changed:
+- cmd: migrate programs to use `certlib.Fetcher` for certificate retrieval
+  (includes `certdump`, `ski`, and others).
+- cmd/ski: update display mode.
+
+Misc:
+- repository fixups and small cleanups.
+
+v1.13.2 - 2025-11-17
+
+Add:
+- certlib/bundler: refactor certificate bundling from cmd/cert-bundler
+  into a separate package.
+
+Changed:
+- cmd/cert-bundler: refactor to use bundler package, and update Dockerfile.
+
+v1.13.1 - 2025-11-17
+
+Add:
+- Dockerfile for cert-bundler.
+
+v1.13.0 - 2025-11-16
+
+Add:
+- cmd/certser: print serial numbers for certificates.
+- lib/HexEncode: add a new hex encode function handling multiple output
+  formats, including with and without colons.
+
+v1.12.4 - 2025-11-16
+
+Changed:
+
+- Linting fixes for twofactor that were previously masked.
+
+v1.12.3 erroneously tagged and pushed
+
+v1.12.2 - 2025-11-16
+
+Changed:
+
+- add rsc.io/qr dependency for twofactor.
+
+v1.12.1 - 2025-11-16
+
+Changed:
+- twofactor: Remove go.{mod,sum}.
+
+v1.12.0 - 2025-11-16
+
+Added
+- twofactor: the github.com/kisom/twofactor repo has been subtree'd
+  into this repo.
+
+v1.11.2 - 2025-11-16
+
+Changed
+- cmd/ski, cmd/csrpubdump, cmd/tlskeypair: centralize
+  certificate/private-key/CSR parsing by reusing certlib helpers.
+  This reduces duplication and improves consistency across commands.
+- csr: CSR parsing in the above commands now uses certlib.ParseCSR,
+  which verifies CSR signatures (behavioral hardening compared to
+  prior parsing without signature verification).
+
 v1.11.1 - 2025-11-16
 
 Changed

Dockerfile

@@ -0,0 +1,38 @@
+# syntax=docker/dockerfile:1
+
+# ----- Builder stage: build all cmd/... tools -----
+FROM golang:1.24-alpine AS builder
+
+# Install necessary build dependencies for fetching modules
+RUN apk add --no-cache git ca-certificates && update-ca-certificates
+
+WORKDIR /src
+
+# Cache modules
+COPY go.mod go.sum ./
+RUN --mount=type=cache,target=/go/pkg/mod \
+    go mod download
+
+# Copy the rest of the source
+COPY . .
+
+# Build and install all commands under ./cmd/... into /out
+ENV CGO_ENABLED=0
+ENV GOBIN=/out
+RUN --mount=type=cache,target=/go/pkg/mod \
+    go install ./cmd/...
+
+# ----- Final runtime image: minimal alpine with tools installed -----
+FROM alpine:3.20
+
+# Ensure common utilities are present
+RUN apk add --no-cache bash curl ca-certificates && update-ca-certificates
+
+# Copy binaries from builder
+COPY --from=builder /out/ /usr/local/bin/
+
+# Working directory for mounting the host CWD
+WORKDIR /work
+
+# Default command shows available tools if run without args
+CMD ["/bin/sh", "-lc", "echo 'Tools installed:' && ls -1 /usr/local/bin && echo '\nMount your project with: docker run --rm -it -v $PWD:/work IMAGE <tool> ...'"]

README.md

@@ -2,39 +2,52 @@ GOUTILS
 
 This is a collection of small utility code I've written in Go; the `cmd/`
 directory has a number of command-line utilities. Rather than keep all
-of these in superfluous repositories of their own, or rewriting them
+of these in superfluous repositories of their own or rewriting them
 for each project, I'm putting them here.
 
-The project can be built with the standard Go tooling, or it can be built
-with Bazel.
+The project can be built with the standard Go tooling.
 
 Contents:
 
     ahash/          Provides hashes from string algorithm specifiers.
     assert/         Error handling, assertion-style.
     backoff/        Implementation of an intelligent backoff strategy.
+    cache/          Implementations of various caches.
+        lru/        Least-recently-used cache.
+        mru/        Most-recently-used cache.
+    certlib/        Library for working with TLS certificates.
     cmd/
         atping/     Automated TCP ping, meant for putting in cronjobs.
-        certchain/  Display the certificate chain from a
-                    TLS connection.
+        ca-signed/  Validate whether a certificate is signed by a CA.
+        cert-bundler/
+                    Create certificate bundles from a source of PEM
+                    certificates.
+        cert-revcheck/
+                    Check whether a certificate has been revoked or is
+                    expired.
+        certchain/  Display the certificate chain from a TLS connection.
         certdump/   Dump certificate information.
         certexpiry/ Print a list of certificate subjects and expiry times
                     or warn about certificates expiring within a certain
                     window.
-        certverify/ Verify a TLS X.509 certificate, optionally printing
+        certverify/ Verify a TLS X.509 certificate file, optionally printing
                     the time to expiry and checking for revocations.
         clustersh/  Run commands or transfer files across multiple
                     servers via SSH.
-        cruntar/    Untar an archive with hard links, copying instead of
+        cruntar/    (Un)tar an archive with hard links, copying instead of
                     linking.
         csrpubdump/ Dump the public key from an X.509 certificate request.
         data_sync/  Sync the user's homedir to external storage.
         diskimg/    Write a disk image to a device.
+        dumpbytes/  Dump the contents of a file as hex bytes, printing it as
+                    a Go []byte literal.
         eig/        EEPROM image generator.
         fragment/   Print a fragment of a file.
+        host/       Go imlpementation of the host(1) command.
         jlp/        JSON linter/prettifier.
         kgz/        Custom gzip compressor / decompressor that handles 99%
                     of my use cases.
+        minmax/     Generate a minmax code for use in uLisp.
         parts/      Simple parts database management for my collection of
                     electronic components.
         pem2bin/    Dump the binary body of a PEM-encoded block.
@@ -44,41 +57,45 @@ Contents:
                     in a bundle.
         renfnv/     Rename a file to base32-encoded 64-bit FNV-1a hash.
         rhash/      Compute the digest of remote files.
+        rolldie/    Roll some dice.
         showimp/    List the external (e.g. non-stdlib and outside the
                     current working directory) imports for a Go file.
         ski         Display the SKI for PEM-encoded TLS material.
         sprox/      Simple TCP proxy.
-        stealchain/ Dump the verified chain from a TLS
-                    connection to a server.
-        stealchain- Dump the verified chain from a TLS
-          server/   connection from a client.
+        stealchain/ Dump the verified chain from a TLS connection to a
+                    server.
+        stealchain-server/
+                    Dump the verified chain from a TLS connection from
+                    from a client.
         subjhash/   Print or match subject info from a certificate.
+        tlsinfo/    Print information about a TLS connection (the TLS version
+                    and cipher suite).
         tlskeypair/ Check whether a TLS certificate and key file match.
         utc/        Convert times to UTC.
         yamll/      A small YAML linter.
+        zsearch/    Search for a string in directory of gzipped files.
     config/         A simple global configuration system where configuration
                     data is pulled from a file or an environment variable
                     transparently.
+        iniconf/    A simple INI-style configuration system.
     dbg/            A debug printer.
     die/            Death of a program.
     fileutil/       Common file functions.
     lib/            Commonly-useful functions for writing Go programs.
+    log/            A syslog library.
     logging/        A logging library.
     mwc/            MultiwriteCloser implementation.
-    rand/           Utilities for working with math/rand.
     sbuf/           A byte buffer that can be wiped.
     seekbuf/        A read-seekable byte buffer.
     syslog/         Syslog-type logging.
     tee/            Emulate tee(1)'s functionality in io.Writers.
     testio/         Various I/O utilities useful during testing.
-    testutil/       Various utility functions useful during testing.
-
+	twofactor/      Two-factor authentication.
 
 Each program should have a small README in the directory with more
 information.
 
-All code here is licensed under the ISC license.
-
+All code here is licensed under the Apache 2.0 license.
 
 Error handling
 --------------
@@ -99,7 +116,7 @@ Examples:
 ```
 cert, err := certlib.LoadCertificate(path)
 if err != nil {
-    // sentinel match
+    // sentinel match:
     if errors.Is(err, certerr.ErrEmptyCertificate) {
         // handle empty input
     }
@@ -116,5 +133,3 @@ if err != nil {
     }
 }
 ```
-
-Avoid including sensitive data (keys, passwords, tokens) in error messages.

backoff/backoff_test.go

@@ -91,7 +91,7 @@ func TestReset(t *testing.T) {
 	}
 }
 
-const decay = 25 * time.Millisecond
+const decay = time.Second
 const maxDuration = 10 * time.Millisecond
 const interval = time.Millisecond
 

certlib/bundler/bundler.go

@@ -0,0 +1,677 @@
+package bundler
+
+import (
+	"archive/tar"
+	"archive/zip"
+	"compress/gzip"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+
+	"gopkg.in/yaml.v2"
+
+	"git.wntrmute.dev/kyle/goutils/certlib"
+)
+
+const defaultFileMode = 0644
+
+// Config represents the top-level YAML configuration.
+type Config struct {
+	Config struct {
+		Hashes string `yaml:"hashes"`
+		Expiry string `yaml:"expiry"`
+	} `yaml:"config"`
+	Chains map[string]ChainGroup `yaml:"chains"`
+}
+
+// ChainGroup represents a named group of certificate chains.
+type ChainGroup struct {
+	Certs   []CertChain `yaml:"certs"`
+	Outputs Outputs     `yaml:"outputs"`
+}
+
+// CertChain represents a root certificate and its intermediates.
+type CertChain struct {
+	Root          string   `yaml:"root"`
+	Intermediates []string `yaml:"intermediates"`
+}
+
+// Outputs defines output format options.
+type Outputs struct {
+	IncludeSingle     bool     `yaml:"include_single"`
+	IncludeIndividual bool     `yaml:"include_individual"`
+	Manifest          bool     `yaml:"manifest"`
+	Formats           []string `yaml:"formats"`
+	Encoding          string   `yaml:"encoding"`
+}
+
+var formatExtensions = map[string]string{
+	"zip": ".zip",
+	"tgz": ".tar.gz",
+}
+
+// Run performs the bundling operation given a config file path and an output directory.
+func Run(configFile string, outputDir string) error {
+	if configFile == "" {
+		return errors.New("configuration file required")
+	}
+
+	cfg, err := loadConfig(configFile)
+	if err != nil {
+		return fmt.Errorf("loading config: %w", err)
+	}
+
+	expiryDuration := 365 * 24 * time.Hour
+	if cfg.Config.Expiry != "" {
+		expiryDuration, err = parseDuration(cfg.Config.Expiry)
+		if err != nil {
+			return fmt.Errorf("parsing expiry: %w", err)
+		}
+	}
+
+	if err = os.MkdirAll(outputDir, 0750); err != nil {
+		return fmt.Errorf("creating output directory: %w", err)
+	}
+
+	totalFormats := 0
+	for _, group := range cfg.Chains {
+		totalFormats += len(group.Outputs.Formats)
+	}
+	createdFiles := make([]string, 0, totalFormats)
+	for groupName, group := range cfg.Chains {
+		files, perr := processChainGroup(groupName, group, expiryDuration, outputDir)
+		if perr != nil {
+			return fmt.Errorf("processing chain group %s: %w", groupName, perr)
+		}
+		createdFiles = append(createdFiles, files...)
+	}
+
+	if cfg.Config.Hashes != "" {
+		hashFile := filepath.Join(outputDir, cfg.Config.Hashes)
+		if gerr := generateHashFile(hashFile, createdFiles); gerr != nil {
+			return fmt.Errorf("generating hash file: %w", gerr)
+		}
+	}
+
+	return nil
+}
+
+func loadConfig(path string) (*Config, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	var cfg Config
+	if uerr := yaml.Unmarshal(data, &cfg); uerr != nil {
+		return nil, uerr
+	}
+
+	return &cfg, nil
+}
+
+func parseDuration(s string) (time.Duration, error) {
+	// Support simple formats like "1y", "6m", "30d"
+	if len(s) < 2 {
+		return 0, fmt.Errorf("invalid duration format: %s", s)
+	}
+
+	unit := s[len(s)-1]
+	value := s[:len(s)-1]
+
+	var multiplier time.Duration
+	switch unit {
+	case 'y', 'Y':
+		multiplier = 365 * 24 * time.Hour
+	case 'm', 'M':
+		multiplier = 30 * 24 * time.Hour
+	case 'd', 'D':
+		multiplier = 24 * time.Hour
+	default:
+		return time.ParseDuration(s)
+	}
+
+	var num int
+	_, err := fmt.Sscanf(value, "%d", &num)
+	if err != nil {
+		return 0, fmt.Errorf("invalid duration value: %s", s)
+	}
+
+	return time.Duration(num) * multiplier, nil
+}
+
+func processChainGroup(
+	groupName string,
+	group ChainGroup,
+	expiryDuration time.Duration,
+	outputDir string,
+) ([]string, error) {
+	// Default encoding to "pem" if not specified
+	encoding := group.Outputs.Encoding
+	if encoding == "" {
+		encoding = "pem"
+	}
+
+	// Collect certificates from all chains in the group
+	singleFileCerts, individualCerts, sourcePaths, err := loadAndCollectCerts(
+		group.Certs,
+		group.Outputs,
+		expiryDuration,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// Prepare files for inclusion in archives
+	archiveFiles, err := prepareArchiveFiles(singleFileCerts, individualCerts, sourcePaths, group.Outputs, encoding)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create archives for the entire group
+	createdFiles, err := createArchiveFiles(groupName, group.Outputs.Formats, archiveFiles, outputDir)
+	if err != nil {
+		return nil, err
+	}
+
+	return createdFiles, nil
+}
+
+// loadAndCollectCerts loads all certificates from chains and collects them for processing.
+func loadAndCollectCerts(
+	chains []CertChain,
+	outputs Outputs,
+	expiryDuration time.Duration,
+) ([]*x509.Certificate, []certWithPath, []string, error) {
+	var singleFileCerts []*x509.Certificate
+	var individualCerts []certWithPath
+	var sourcePaths []string
+
+	for _, chain := range chains {
+		s, i, cerr := collectFromChain(chain, outputs, expiryDuration)
+		if cerr != nil {
+			return nil, nil, nil, cerr
+		}
+		if len(s) > 0 {
+			singleFileCerts = append(singleFileCerts, s...)
+		}
+		if len(i) > 0 {
+			individualCerts = append(individualCerts, i...)
+		}
+		// Record source paths for timestamp preservation
+		// Only append when loading succeeded
+		sourcePaths = append(sourcePaths, chain.Root)
+		sourcePaths = append(sourcePaths, chain.Intermediates...)
+	}
+
+	return singleFileCerts, individualCerts, sourcePaths, nil
+}
+
+// collectFromChain loads a single chain, performs checks, and returns the certs to include.
+func collectFromChain(
+	chain CertChain,
+	outputs Outputs,
+	expiryDuration time.Duration,
+) (
+	[]*x509.Certificate,
+	[]certWithPath,
+	error,
+) {
+	var single []*x509.Certificate
+	var indiv []certWithPath
+
+	// Load root certificate
+	rootCert, rerr := certlib.LoadCertificate(chain.Root)
+	if rerr != nil {
+		return nil, nil, fmt.Errorf("failed to load root certificate %s: %w", chain.Root, rerr)
+	}
+
+	// Check expiry for root
+	checkExpiry(chain.Root, rootCert, expiryDuration)
+
+	// Add root to collections if needed
+	if outputs.IncludeSingle {
+		single = append(single, rootCert)
+	}
+	if outputs.IncludeIndividual {
+		indiv = append(indiv, certWithPath{cert: rootCert, path: chain.Root})
+	}
+
+	// Load and validate intermediates
+	for _, intPath := range chain.Intermediates {
+		intCert, lerr := certlib.LoadCertificate(intPath)
+		if lerr != nil {
+			return nil, nil, fmt.Errorf("failed to load intermediate certificate %s: %w", intPath, lerr)
+		}
+
+		// Validate that intermediate is signed by root
+		if sigErr := intCert.CheckSignatureFrom(rootCert); sigErr != nil {
+			return nil, nil, fmt.Errorf(
+				"intermediate %s is not properly signed by root %s: %w",
+				intPath,
+				chain.Root,
+				sigErr,
+			)
+		}
+
+		// Check expiry for intermediate
+		checkExpiry(intPath, intCert, expiryDuration)
+
+		// Add intermediate to collections if needed
+		if outputs.IncludeSingle {
+			single = append(single, intCert)
+		}
+		if outputs.IncludeIndividual {
+			indiv = append(indiv, certWithPath{cert: intCert, path: intPath})
+		}
+	}
+
+	return single, indiv, nil
+}
+
+// prepareArchiveFiles prepares all files to be included in archives.
+func prepareArchiveFiles(
+	singleFileCerts []*x509.Certificate,
+	individualCerts []certWithPath,
+	sourcePaths []string,
+	outputs Outputs,
+	encoding string,
+) ([]fileEntry, error) {
+	var archiveFiles []fileEntry
+
+	// Track used filenames to avoid collisions inside archives
+	usedNames := make(map[string]int)
+
+	// Handle a single bundle file
+	if outputs.IncludeSingle && len(singleFileCerts) > 0 {
+		bundleTime := maxModTime(sourcePaths)
+		files, err := encodeCertsToFiles(singleFileCerts, "bundle", encoding, true)
+		if err != nil {
+			return nil, fmt.Errorf("failed to encode single bundle: %w", err)
+		}
+		for i := range files {
+			files[i].name = makeUniqueName(files[i].name, usedNames)
+			files[i].modTime = bundleTime
+			// Best-effort: we do not have a portable birth/creation time.
+			// Use the same timestamp for created time to track deterministically.
+			files[i].createTime = bundleTime
+		}
+		archiveFiles = append(archiveFiles, files...)
+	}
+
+	// Handle individual files
+	if outputs.IncludeIndividual {
+		for _, cp := range individualCerts {
+			baseName := strings.TrimSuffix(filepath.Base(cp.path), filepath.Ext(cp.path))
+			files, err := encodeCertsToFiles([]*x509.Certificate{cp.cert}, baseName, encoding, false)
+			if err != nil {
+				return nil, fmt.Errorf("failed to encode individual cert %s: %w", cp.path, err)
+			}
+			mt := fileModTime(cp.path)
+			for i := range files {
+				files[i].name = makeUniqueName(files[i].name, usedNames)
+				files[i].modTime = mt
+				files[i].createTime = mt
+			}
+			archiveFiles = append(archiveFiles, files...)
+		}
+	}
+
+	// Generate manifest if requested
+	if outputs.Manifest {
+		manifestContent := generateManifest(archiveFiles)
+		manifestName := makeUniqueName("MANIFEST", usedNames)
+		mt := maxModTime(sourcePaths)
+		archiveFiles = append(archiveFiles, fileEntry{
+			name:       manifestName,
+			content:    manifestContent,
+			modTime:    mt,
+			createTime: mt,
+		})
+	}
+
+	return archiveFiles, nil
+}
+
+// createArchiveFiles creates archive files in the specified formats.
+func createArchiveFiles(
+	groupName string,
+	formats []string,
+	archiveFiles []fileEntry,
+	outputDir string,
+) ([]string, error) {
+	createdFiles := make([]string, 0, len(formats))
+
+	for _, format := range formats {
+		ext, ok := formatExtensions[format]
+		if !ok {
+			return nil, fmt.Errorf("unsupported format: %s", format)
+		}
+		archivePath := filepath.Join(outputDir, groupName+ext)
+		switch format {
+		case "zip":
+			if err := createZipArchive(archivePath, archiveFiles); err != nil {
+				return nil, fmt.Errorf("failed to create zip archive: %w", err)
+			}
+		case "tgz":
+			if err := createTarGzArchive(archivePath, archiveFiles); err != nil {
+				return nil, fmt.Errorf("failed to create tar.gz archive: %w", err)
+			}
+		default:
+			return nil, fmt.Errorf("unsupported format: %s", format)
+		}
+		createdFiles = append(createdFiles, archivePath)
+	}
+
+	return createdFiles, nil
+}
+
+func checkExpiry(path string, cert *x509.Certificate, expiryDuration time.Duration) {
+	now := time.Now()
+	expiryThreshold := now.Add(expiryDuration)
+
+	if cert.NotAfter.Before(expiryThreshold) {
+		daysUntilExpiry := int(cert.NotAfter.Sub(now).Hours() / 24)
+		if daysUntilExpiry < 0 {
+			fmt.Fprintf(
+				os.Stderr,
+				"WARNING: Certificate %s has EXPIRED (expired %d days ago)\n",
+				path,
+				-daysUntilExpiry,
+			)
+		} else {
+			fmt.Fprintf(os.Stderr, "WARNING: Certificate %s will expire in %d days (on %s)\n", path, daysUntilExpiry, cert.NotAfter.Format("2006-01-02"))
+		}
+	}
+}
+
+type fileEntry struct {
+	name       string
+	content    []byte
+	modTime    time.Time
+	createTime time.Time
+}
+
+type certWithPath struct {
+	cert *x509.Certificate
+	path string
+}
+
+// encodeCertsToFiles converts certificates to file entries based on encoding type
+// If isSingle is true, certs are concatenated into a single file; otherwise one cert per file.
+func encodeCertsToFiles(
+	certs []*x509.Certificate,
+	baseName string,
+	encoding string,
+	isSingle bool,
+) ([]fileEntry, error) {
+	var files []fileEntry
+
+	switch encoding {
+	case "pem":
+		pemContent := encodeCertsToPEM(certs)
+		files = append(files, fileEntry{
+			name:    baseName + ".pem",
+			content: pemContent,
+		})
+	case "der":
+		if isSingle {
+			// For single file in DER, concatenate all cert DER bytes
+			var derContent []byte
+			for _, cert := range certs {
+				derContent = append(derContent, cert.Raw...)
+			}
+			files = append(files, fileEntry{
+				name:    baseName + ".crt",
+				content: derContent,
+			})
+		} else if len(certs) > 0 {
+			// Individual DER file (should only have one cert)
+			files = append(files, fileEntry{
+				name:    baseName + ".crt",
+				content: certs[0].Raw,
+			})
+		}
+	case "both":
+		// Add PEM version
+		pemContent := encodeCertsToPEM(certs)
+		files = append(files, fileEntry{
+			name:    baseName + ".pem",
+			content: pemContent,
+		})
+		// Add DER version
+		if isSingle {
+			var derContent []byte
+			for _, cert := range certs {
+				derContent = append(derContent, cert.Raw...)
+			}
+			files = append(files, fileEntry{
+				name:    baseName + ".crt",
+				content: derContent,
+			})
+		} else if len(certs) > 0 {
+			files = append(files, fileEntry{
+				name:    baseName + ".crt",
+				content: certs[0].Raw,
+			})
+		}
+	default:
+		return nil, fmt.Errorf("unsupported encoding: %s (must be 'pem', 'der', or 'both')", encoding)
+	}
+
+	return files, nil
+}
+
+// encodeCertsToPEM encodes certificates to PEM format.
+func encodeCertsToPEM(certs []*x509.Certificate) []byte {
+	var pemContent []byte
+	for _, cert := range certs {
+		pemBlock := &pem.Block{
+			Type:  "CERTIFICATE",
+			Bytes: cert.Raw,
+		}
+		pemContent = append(pemContent, pem.EncodeToMemory(pemBlock)...)
+	}
+	return pemContent
+}
+
+func generateManifest(files []fileEntry) []byte {
+	// Build a sorted list of files by filename to ensure deterministic manifest ordering
+	sorted := make([]fileEntry, 0, len(files))
+	for _, f := range files {
+		// Defensive: skip any existing manifest entry
+		if f.name == "MANIFEST" {
+			continue
+		}
+		sorted = append(sorted, f)
+	}
+	sort.Slice(sorted, func(i, j int) bool { return sorted[i].name < sorted[j].name })
+
+	var manifest strings.Builder
+	for _, file := range sorted {
+		hash := sha256.Sum256(file.content)
+		manifest.WriteString(fmt.Sprintf("%x  %s\n", hash, file.name))
+	}
+	return []byte(manifest.String())
+}
+
+// closeWithErr attempts to close all provided closers, joining any close errors with baseErr.
+func closeWithErr(baseErr error, closers ...io.Closer) error {
+	for _, c := range closers {
+		if c == nil {
+			continue
+		}
+		if cerr := c.Close(); cerr != nil {
+			baseErr = errors.Join(baseErr, cerr)
+		}
+	}
+	return baseErr
+}
+
+func createZipArchive(path string, files []fileEntry) error {
+	f, zerr := os.Create(path)
+	if zerr != nil {
+		return zerr
+	}
+
+	w := zip.NewWriter(f)
+
+	for _, file := range files {
+		hdr := &zip.FileHeader{
+			Name:   file.name,
+			Method: zip.Deflate,
+		}
+		if !file.modTime.IsZero() {
+			hdr.SetModTime(file.modTime)
+		}
+		fw, werr := w.CreateHeader(hdr)
+		if werr != nil {
+			return closeWithErr(werr, w, f)
+		}
+		if _, werr = fw.Write(file.content); werr != nil {
+			return closeWithErr(werr, w, f)
+		}
+	}
+
+	// Check errors on close operations
+	if cerr := w.Close(); cerr != nil {
+		_ = f.Close()
+		return cerr
+	}
+	return f.Close()
+}
+
+func createTarGzArchive(path string, files []fileEntry) error {
+	f, terr := os.Create(path)
+	if terr != nil {
+		return terr
+	}
+
+	gw := gzip.NewWriter(f)
+	tw := tar.NewWriter(gw)
+
+	for _, file := range files {
+		hdr := &tar.Header{
+			Name: file.name,
+			Uid:  0,
+			Gid:  0,
+			Mode: defaultFileMode,
+			Size: int64(len(file.content)),
+			ModTime: func() time.Time {
+				if file.modTime.IsZero() {
+					return time.Now()
+				}
+				return file.modTime
+			}(),
+		}
+		// Set additional times if supported
+		hdr.AccessTime = hdr.ModTime
+		if !file.createTime.IsZero() {
+			hdr.ChangeTime = file.createTime
+		} else {
+			hdr.ChangeTime = hdr.ModTime
+		}
+		if herr := tw.WriteHeader(hdr); herr != nil {
+			return closeWithErr(herr, tw, gw, f)
+		}
+		if _, werr := tw.Write(file.content); werr != nil {
+			return closeWithErr(werr, tw, gw, f)
+		}
+	}
+
+	// Check errors on close operations in the correct order
+	if cerr := tw.Close(); cerr != nil {
+		_ = gw.Close()
+		_ = f.Close()
+		return cerr
+	}
+	if cerr := gw.Close(); cerr != nil {
+		_ = f.Close()
+		return cerr
+	}
+	return f.Close()
+}
+
+func generateHashFile(path string, files []string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	for _, file := range files {
+		data, rerr := os.ReadFile(file)
+		if rerr != nil {
+			return rerr
+		}
+
+		hash := sha256.Sum256(data)
+		fmt.Fprintf(f, "%x  %s\n", hash, filepath.Base(file))
+	}
+
+	return nil
+}
+
+// makeUniqueName ensures that each file name within the archive is unique by appending
+// an incremental numeric suffix before the extension when collisions occur.
+// Example: "root.pem" -> "root-2.pem", "root-3.pem", etc.
+func makeUniqueName(name string, used map[string]int) string {
+	// If unused, mark and return as-is
+	if _, ok := used[name]; !ok {
+		used[name] = 1
+		return name
+	}
+
+	ext := filepath.Ext(name)
+	base := strings.TrimSuffix(name, ext)
+	// Track a counter per base+ext key
+	key := base + ext
+	counter := max(used[key], 1)
+	for {
+		counter++
+		candidate := fmt.Sprintf("%s-%d%s", base, counter, ext)
+		if _, exists := used[candidate]; !exists {
+			used[key] = counter
+			used[candidate] = 1
+			return candidate
+		}
+	}
+}
+
+// fileModTime returns the file's modification time, or time.Now() if stat fails.
+func fileModTime(path string) time.Time {
+	fi, err := os.Stat(path)
+	if err != nil {
+		return time.Now()
+	}
+	return fi.ModTime()
+}
+
+// maxModTime returns the latest modification time across provided paths.
+// If the list is empty or stats fail, returns time.Now().
+func maxModTime(paths []string) time.Time {
+	var zero time.Time
+	maxTime := zero
+	for _, p := range paths {
+		fi, err := os.Stat(p)
+		if err != nil {
+			continue
+		}
+		mt := fi.ModTime()
+		if maxTime.IsZero() || mt.After(maxTime) {
+			maxTime = mt
+		}
+	}
+	if maxTime.IsZero() {
+		return time.Now()
+	}
+	return maxTime
+}

certlib/certlib.go

@@ -4,6 +4,7 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"errors"
+	"fmt"
 	"os"
 
 	"git.wntrmute.dev/kyle/goutils/certlib/certerr"
@@ -93,3 +94,18 @@ func LoadCertificates(path string) ([]*x509.Certificate, error) {
 
 	return ReadCertificates(in)
 }
+
+func PoolFromBytes(certBytes []byte) (*x509.CertPool, error) {
+	pool := x509.NewCertPool()
+
+	certs, err := ReadCertificates(certBytes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read certificates: %w", err)
+	}
+
+	for _, cert := range certs {
+		pool.AddCert(cert)
+	}
+
+	return pool, nil
+}

certlib/dump/dump.go

@@ -0,0 +1,339 @@
+// Package dump implements tooling for dumping certificate information.
+package dump
+
+import (
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"fmt"
+	"io"
+	"os"
+	"sort"
+	"strings"
+
+	"github.com/kr/text"
+
+	"git.wntrmute.dev/kyle/goutils/lib"
+)
+
+const (
+	sSHA256 = "SHA256"
+	sSHA512 = "SHA512"
+)
+
+var keyUsage = map[x509.KeyUsage]string{
+	x509.KeyUsageDigitalSignature:  "digital signature",
+	x509.KeyUsageContentCommitment: "content commitment",
+	x509.KeyUsageKeyEncipherment:   "key encipherment",
+	x509.KeyUsageKeyAgreement:      "key agreement",
+	x509.KeyUsageDataEncipherment:  "data encipherment",
+	x509.KeyUsageCertSign:          "cert sign",
+	x509.KeyUsageCRLSign:           "crl sign",
+	x509.KeyUsageEncipherOnly:      "encipher only",
+	x509.KeyUsageDecipherOnly:      "decipher only",
+}
+
+var extKeyUsages = map[x509.ExtKeyUsage]string{
+	x509.ExtKeyUsageAny:                            "any",
+	x509.ExtKeyUsageServerAuth:                     "server auth",
+	x509.ExtKeyUsageClientAuth:                     "client auth",
+	x509.ExtKeyUsageCodeSigning:                    "code signing",
+	x509.ExtKeyUsageEmailProtection:                "s/mime",
+	x509.ExtKeyUsageIPSECEndSystem:                 "ipsec end system",
+	x509.ExtKeyUsageIPSECTunnel:                    "ipsec tunnel",
+	x509.ExtKeyUsageIPSECUser:                      "ipsec user",
+	x509.ExtKeyUsageTimeStamping:                   "timestamping",
+	x509.ExtKeyUsageOCSPSigning:                    "ocsp signing",
+	x509.ExtKeyUsageMicrosoftServerGatedCrypto:     "microsoft sgc",
+	x509.ExtKeyUsageNetscapeServerGatedCrypto:      "netscape sgc",
+	x509.ExtKeyUsageMicrosoftCommercialCodeSigning: "microsoft commercial code signing",
+	x509.ExtKeyUsageMicrosoftKernelCodeSigning:     "microsoft kernel code signing",
+}
+
+func sigAlgoPK(a x509.SignatureAlgorithm) string {
+	switch a {
+	case x509.MD2WithRSA, x509.MD5WithRSA, x509.SHA1WithRSA, x509.SHA256WithRSA, x509.SHA384WithRSA, x509.SHA512WithRSA:
+		return "RSA"
+	case x509.SHA256WithRSAPSS, x509.SHA384WithRSAPSS, x509.SHA512WithRSAPSS:
+		return "RSA-PSS"
+	case x509.ECDSAWithSHA1, x509.ECDSAWithSHA256, x509.ECDSAWithSHA384, x509.ECDSAWithSHA512:
+		return "ECDSA"
+	case x509.DSAWithSHA1, x509.DSAWithSHA256:
+		return "DSA"
+	case x509.PureEd25519:
+		return "Ed25519"
+	case x509.UnknownSignatureAlgorithm:
+		return "unknown public key algorithm"
+	default:
+		return "unknown public key algorithm"
+	}
+}
+
+func sigAlgoHash(a x509.SignatureAlgorithm) string {
+	switch a {
+	case x509.MD2WithRSA:
+		return "MD2"
+	case x509.MD5WithRSA:
+		return "MD5"
+	case x509.SHA1WithRSA, x509.ECDSAWithSHA1, x509.DSAWithSHA1:
+		return "SHA1"
+	case x509.SHA256WithRSA, x509.ECDSAWithSHA256, x509.DSAWithSHA256:
+		return sSHA256
+	case x509.SHA256WithRSAPSS:
+		return sSHA256
+	case x509.SHA384WithRSA, x509.ECDSAWithSHA384:
+		return "SHA384"
+	case x509.SHA384WithRSAPSS:
+		return "SHA384"
+	case x509.SHA512WithRSA, x509.ECDSAWithSHA512:
+		return sSHA512
+	case x509.SHA512WithRSAPSS:
+		return sSHA512
+	case x509.PureEd25519:
+		return sSHA512
+	case x509.UnknownSignatureAlgorithm:
+		return "unknown hash algorithm"
+	default:
+		return "unknown hash algorithm"
+	}
+}
+
+const maxLine = 78
+
+func makeIndent(n int) string {
+	s := "    "
+	var sSb97 strings.Builder
+	for range n {
+		sSb97.WriteString("        ")
+	}
+	s += sSb97.String()
+	return s
+}
+
+func indentLen(n int) int {
+	return 4 + (8 * n)
+}
+
+// this isn't real efficient, but that's not a problem here.
+func wrap(s string, indent int) string {
+	if indent > 3 {
+		indent = 3
+	}
+
+	wrapped := text.Wrap(s, maxLine)
+	lines := strings.SplitN(wrapped, "\n", 2)
+	if len(lines) == 1 {
+		return lines[0]
+	}
+
+	if (maxLine - indentLen(indent)) <= 0 {
+		panic("too much indentation")
+	}
+
+	rest := strings.Join(lines[1:], " ")
+	wrapped = text.Wrap(rest, maxLine-indentLen(indent))
+	return lines[0] + "\n" + text.Indent(wrapped, makeIndent(indent))
+}
+
+func dumpHex(in []byte) string {
+	return lib.HexEncode(in, lib.HexEncodeUpperColon)
+}
+
+func certPublic(cert *x509.Certificate) string {
+	switch pub := cert.PublicKey.(type) {
+	case *rsa.PublicKey:
+		return fmt.Sprintf("RSA-%d", pub.N.BitLen())
+	case *ecdsa.PublicKey:
+		switch pub.Curve {
+		case elliptic.P256():
+			return "ECDSA-prime256v1"
+		case elliptic.P384():
+			return "ECDSA-secp384r1"
+		case elliptic.P521():
+			return "ECDSA-secp521r1"
+		default:
+			return "ECDSA (unknown curve)"
+		}
+	case *dsa.PublicKey:
+		return "DSA"
+	default:
+		return "Unknown"
+	}
+}
+
+func DisplayName(name pkix.Name) string {
+	var ns []string
+
+	if name.CommonName != "" {
+		ns = append(ns, name.CommonName)
+	}
+
+	for i := range name.Country {
+		ns = append(ns, fmt.Sprintf("C=%s", name.Country[i]))
+	}
+
+	for i := range name.Organization {
+		ns = append(ns, fmt.Sprintf("O=%s", name.Organization[i]))
+	}
+
+	for i := range name.OrganizationalUnit {
+		ns = append(ns, fmt.Sprintf("OU=%s", name.OrganizationalUnit[i]))
+	}
+
+	for i := range name.Locality {
+		ns = append(ns, fmt.Sprintf("L=%s", name.Locality[i]))
+	}
+
+	for i := range name.Province {
+		ns = append(ns, fmt.Sprintf("ST=%s", name.Province[i]))
+	}
+
+	if len(ns) > 0 {
+		return "/" + strings.Join(ns, "/")
+	}
+
+	return "*** no subject information ***"
+}
+
+func keyUsages(ku x509.KeyUsage) string {
+	var uses []string
+
+	for u, s := range keyUsage {
+		if (ku & u) != 0 {
+			uses = append(uses, s)
+		}
+	}
+	sort.Strings(uses)
+
+	return strings.Join(uses, ", ")
+}
+
+func extUsage(ext []x509.ExtKeyUsage) string {
+	ns := make([]string, 0, len(ext))
+	for i := range ext {
+		ns = append(ns, extKeyUsages[ext[i]])
+	}
+	sort.Strings(ns)
+
+	return strings.Join(ns, ", ")
+}
+
+func showBasicConstraints(cert *x509.Certificate) {
+	fmt.Fprint(os.Stdout, "\tBasic constraints: ")
+	if cert.BasicConstraintsValid {
+		fmt.Fprint(os.Stdout, "valid")
+	} else {
+		fmt.Fprint(os.Stdout, "invalid")
+	}
+
+	if cert.IsCA {
+		fmt.Fprint(os.Stdout, ", is a CA certificate")
+		if !cert.BasicConstraintsValid {
+			fmt.Fprint(os.Stdout, " (basic constraint failure)")
+		}
+	} else {
+		fmt.Fprint(os.Stdout, ", is not a CA certificate")
+		if cert.KeyUsage&x509.KeyUsageKeyEncipherment != 0 {
+			fmt.Fprint(os.Stdout, " (key encipherment usage enabled!)")
+		}
+	}
+
+	if (cert.MaxPathLen == 0 && cert.MaxPathLenZero) || (cert.MaxPathLen > 0) {
+		fmt.Fprintf(os.Stdout, ", max path length %d", cert.MaxPathLen)
+	}
+
+	fmt.Fprintln(os.Stdout)
+}
+
+var (
+	dateFormat string
+	showHash   bool // if true, print a SHA256 hash of the certificate's Raw field
+)
+
+func wrapPrint(text string, indent int) {
+	tabs := ""
+	var tabsSb140 strings.Builder
+	for range indent {
+		tabsSb140.WriteString("\t")
+	}
+	tabs += tabsSb140.String()
+
+	fmt.Fprintf(os.Stdout, tabs+"%s\n", wrap(text, indent))
+}
+
+func DisplayCert(w io.Writer, cert *x509.Certificate) {
+	fmt.Fprintln(w, "CERTIFICATE")
+	if showHash {
+		fmt.Fprintln(w, wrap(fmt.Sprintf("SHA256: %x", sha256.Sum256(cert.Raw)), 0))
+	}
+	fmt.Fprintln(w, wrap("Subject: "+DisplayName(cert.Subject), 0))
+	fmt.Fprintln(w, wrap("Issuer: "+DisplayName(cert.Issuer), 0))
+	fmt.Fprintf(w, "\tSignature algorithm: %s / %s\n", sigAlgoPK(cert.SignatureAlgorithm),
+		sigAlgoHash(cert.SignatureAlgorithm))
+	fmt.Fprintln(w, "Details:")
+	wrapPrint("Public key: "+certPublic(cert), 1)
+	fmt.Fprintf(w, "\tSerial number: %s\n", cert.SerialNumber)
+
+	if len(cert.AuthorityKeyId) > 0 {
+		fmt.Fprintf(w, "\t%s\n", wrap("AKI: "+dumpHex(cert.AuthorityKeyId), 1))
+	}
+	if len(cert.SubjectKeyId) > 0 {
+		fmt.Fprintf(w, "\t%s\n", wrap("SKI: "+dumpHex(cert.SubjectKeyId), 1))
+	}
+
+	wrapPrint("Valid from: "+cert.NotBefore.Format(dateFormat), 1)
+	fmt.Fprintf(w, "\t     until: %s\n", cert.NotAfter.Format(dateFormat))
+	fmt.Fprintf(w, "\tKey usages: %s\n", keyUsages(cert.KeyUsage))
+
+	if len(cert.ExtKeyUsage) > 0 {
+		fmt.Fprintf(w, "\tExtended usages: %s\n", extUsage(cert.ExtKeyUsage))
+	}
+
+	showBasicConstraints(cert)
+
+	validNames := make([]string, 0, len(cert.DNSNames)+len(cert.EmailAddresses)+len(cert.IPAddresses))
+	for i := range cert.DNSNames {
+		validNames = append(validNames, "dns:"+cert.DNSNames[i])
+	}
+
+	for i := range cert.EmailAddresses {
+		validNames = append(validNames, "email:"+cert.EmailAddresses[i])
+	}
+
+	for i := range cert.IPAddresses {
+		validNames = append(validNames, "ip:"+cert.IPAddresses[i].String())
+	}
+
+	sans := fmt.Sprintf("SANs (%d): %s\n", len(validNames), strings.Join(validNames, ", "))
+	wrapPrint(sans, 1)
+
+	l := len(cert.IssuingCertificateURL)
+	if l != 0 {
+		var aia string
+		if l == 1 {
+			aia = "AIA"
+		} else {
+			aia = "AIAs"
+		}
+		wrapPrint(fmt.Sprintf("%d %s:", l, aia), 1)
+		for _, url := range cert.IssuingCertificateURL {
+			wrapPrint(url, 2)
+		}
+	}
+
+	l = len(cert.OCSPServer)
+	if l > 0 {
+		title := "OCSP server"
+		if l > 1 {
+			title += "s"
+		}
+		wrapPrint(title+":\n", 1)
+		for _, ocspServer := range cert.OCSPServer {
+			wrapPrint(fmt.Sprintf("- %s\n", ocspServer), 2)
+		}
+	}
+}

certlib/helpers.go

@@ -396,6 +396,45 @@ func ParseOneCertificateFromPEM(certsPEM []byte) ([]*x509.Certificate, []byte, e
 	return certs, rest, nil
 }
 
+// LoadFullCertPool returns a certificate pool with roots and intermediates
+// from disk. If no roots are provided, the system root pool will be used.
+func LoadFullCertPool(roots, intermediates string) (*x509.CertPool, error) {
+	var err error
+
+	pool := x509.NewCertPool()
+
+	if roots == "" {
+		pool, err = x509.SystemCertPool()
+		if err != nil {
+			return nil, fmt.Errorf("loading system cert pool: %w", err)
+		}
+	} else {
+		var rootCerts []*x509.Certificate
+		rootCerts, err = LoadCertificates(roots)
+		if err != nil {
+			return nil, fmt.Errorf("loading roots: %w", err)
+		}
+
+		for _, cert := range rootCerts {
+			pool.AddCert(cert)
+		}
+	}
+
+	if intermediates != "" {
+		var intCerts []*x509.Certificate
+		intCerts, err = LoadCertificates(intermediates)
+		if err != nil {
+			return nil, fmt.Errorf("loading intermediates: %w", err)
+		}
+
+		for _, cert := range intCerts {
+			pool.AddCert(cert)
+		}
+	}
+
+	return pool, nil
+}
+
 // LoadPEMCertPool loads a pool of PEM certificates from file.
 func LoadPEMCertPool(certsFile string) (*x509.CertPool, error) {
 	if certsFile == "" {

certlib/hosts/hosts.go

@@ -26,7 +26,12 @@ func parseURL(host string) (string, int, error) {
 		return "", 0, fmt.Errorf("certlib/hosts: invalid host: %s", host)
 	}
 
-	if strings.ToLower(url.Scheme) != "https" {
+	switch strings.ToLower(url.Scheme) {
+	case "https":
+	// OK
+	case "tls":
+	// OK
+	default:
 		return "", 0, errors.New("certlib/hosts: only https scheme supported")
 	}
 
@@ -43,28 +48,28 @@ func parseURL(host string) (string, int, error) {
 }
 
 func parseHostPort(host string) (string, int, error) {
-	host, sport, err := net.SplitHostPort(host)
+	shost, sport, err := net.SplitHostPort(host)
 	if err == nil {
 		portInt, err2 := strconv.ParseInt(sport, 10, 16)
 		if err2 != nil {
 			return "", 0, fmt.Errorf("certlib/hosts: invalid port: %s", sport)
 		}
 
-		return host, int(portInt), nil
+		return shost, int(portInt), nil
 	}
 
 	return host, defaultHTTPSPort, nil
 }
 
 func ParseHost(host string) (*Target, error) {
-	host, port, err := parseURL(host)
+	uhost, port, err := parseURL(host)
 	if err == nil {
-		return &Target{Host: host, Port: port}, nil
+		return &Target{Host: uhost, Port: port}, nil
 	}
 
-	host, port, err = parseHostPort(host)
+	shost, port, err := parseHostPort(host)
 	if err == nil {
-		return &Target{Host: host, Port: port}, nil
+		return &Target{Host: shost, Port: port}, nil
 	}
 
 	return nil, fmt.Errorf("certlib/hosts: invalid host: %s", host)

certlib/hosts/hosts_test.go

@@ -0,0 +1,35 @@
+package hosts_test
+
+import (
+	"testing"
+
+	"git.wntrmute.dev/kyle/goutils/certlib/hosts"
+)
+
+type testCase struct {
+	Host   string
+	Target hosts.Target
+}
+
+var testCases = []testCase{
+	{Host: "server-name", Target: hosts.Target{Host: "server-name", Port: 443}},
+	{Host: "server-name:8443", Target: hosts.Target{Host: "server-name", Port: 8443}},
+	{Host: "tls://server-name", Target: hosts.Target{Host: "server-name", Port: 443}},
+	{Host: "https://server-name", Target: hosts.Target{Host: "server-name", Port: 443}},
+	{Host: "https://server-name:8443", Target: hosts.Target{Host: "server-name", Port: 8443}},
+	{Host: "tls://server-name:8443", Target: hosts.Target{Host: "server-name", Port: 8443}},
+	{Host: "https://server-name/something/else", Target: hosts.Target{Host: "server-name", Port: 443}},
+}
+
+func TestParseHost(t *testing.T) {
+	for i, tc := range testCases {
+		target, err := hosts.ParseHost(tc.Host)
+		if err != nil {
+			t.Fatalf("test case %d: %s", i+1, err)
+		}
+
+		if target.Host != tc.Target.Host {
+			t.Fatalf("test case %d: got host '%s', want host '%s'", i+1, target.Host, tc.Target.Host)
+		}
+	}
+}

certlib/keymatch.go

@@ -0,0 +1,135 @@
+package certlib
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"os"
+)
+
+// LoadPrivateKey loads a private key from disk. It accepts both PEM and DER
+// encodings and supports RSA and ECDSA keys. If the file contains a PEM block,
+// the block type must be one of the recognised private key types.
+func LoadPrivateKey(path string) (crypto.Signer, error) {
+	in, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	in = bytes.TrimSpace(in)
+	if p, _ := pem.Decode(in); p != nil {
+		if !validPEMs[p.Type] {
+			return nil, errors.New("invalid private key file type " + p.Type)
+		}
+		return ParsePrivateKeyPEM(in)
+	}
+
+	return ParsePrivateKeyDER(in)
+}
+
+var validPEMs = map[string]bool{
+	"PRIVATE KEY":     true,
+	"RSA PRIVATE KEY": true,
+	"EC PRIVATE KEY":  true,
+}
+
+const (
+	curveInvalid = iota // any invalid curve
+	curveRSA            // indicates key is an RSA key, not an EC key
+	curveP256
+	curveP384
+	curveP521
+)
+
+func getECCurve(pub any) int {
+	switch pub := pub.(type) {
+	case *ecdsa.PublicKey:
+		switch pub.Curve {
+		case elliptic.P256():
+			return curveP256
+		case elliptic.P384():
+			return curveP384
+		case elliptic.P521():
+			return curveP521
+		default:
+			return curveInvalid
+		}
+	case *rsa.PublicKey:
+		return curveRSA
+	default:
+		return curveInvalid
+	}
+}
+
+// matchRSA compares an RSA public key from certificate against RSA public key from private key.
+// It returns true on match.
+func matchRSA(certPub *rsa.PublicKey, keyPub *rsa.PublicKey) bool {
+	return keyPub.N.Cmp(certPub.N) == 0 && keyPub.E == certPub.E
+}
+
+// matchECDSA compares ECDSA public keys for equality and compatible curve.
+// It returns match=true when they are on the same curve and have the same X/Y.
+// If curves mismatch, match is false.
+func matchECDSA(certPub *ecdsa.PublicKey, keyPub *ecdsa.PublicKey) bool {
+	if getECCurve(certPub) != getECCurve(keyPub) {
+		return false
+	}
+	if keyPub.X.Cmp(certPub.X) != 0 {
+		return false
+	}
+	if keyPub.Y.Cmp(certPub.Y) != 0 {
+		return false
+	}
+	return true
+}
+
+// MatchKeys determines whether the certificate's public key matches the given private key.
+// It returns true if they match; otherwise, it returns false and a human-friendly reason.
+func MatchKeys(cert *x509.Certificate, priv crypto.Signer) (bool, string) {
+	switch keyPub := priv.Public().(type) {
+	case *rsa.PublicKey:
+		switch certPub := cert.PublicKey.(type) {
+		case *rsa.PublicKey:
+			if matchRSA(certPub, keyPub) {
+				return true, ""
+			}
+			return false, "public keys don't match"
+		case *ecdsa.PublicKey:
+			return false, "RSA private key, EC public key"
+		default:
+			return false, fmt.Sprintf("unsupported certificate public key type: %T", cert.PublicKey)
+		}
+	case *ecdsa.PublicKey:
+		switch certPub := cert.PublicKey.(type) {
+		case *ecdsa.PublicKey:
+			if matchECDSA(certPub, keyPub) {
+				return true, ""
+			}
+			// Determine a more precise reason
+			kc := getECCurve(keyPub)
+			cc := getECCurve(certPub)
+			if kc == curveInvalid {
+				return false, "invalid private key curve"
+			}
+			if cc == curveRSA {
+				return false, "private key is EC, certificate is RSA"
+			}
+			if kc != cc {
+				return false, "EC curves don't match"
+			}
+			return false, "public keys don't match"
+		case *rsa.PublicKey:
+			return false, "private key is EC, certificate is RSA"
+		default:
+			return false, fmt.Sprintf("unsupported certificate public key type: %T", cert.PublicKey)
+		}
+	default:
+		return false, fmt.Sprintf("unrecognised private key type: %T", priv.Public())
+	}
+}

certlib/ski/ski.go

@@ -0,0 +1,157 @@
+package ski
+
+import (
+	"bytes"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/rsa"
+	"crypto/sha1" // #nosec G505 this is the standard
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"encoding/pem"
+	"fmt"
+	"os"
+
+	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/die"
+	"git.wntrmute.dev/kyle/goutils/lib"
+)
+
+const (
+	keyTypeRSA     = "RSA"
+	keyTypeECDSA   = "ECDSA"
+	keyTypeEd25519 = "Ed25519"
+)
+
+type subjectPublicKeyInfo struct {
+	Algorithm        pkix.AlgorithmIdentifier
+	SubjectPublicKey asn1.BitString
+}
+
+type KeyInfo struct {
+	PublicKey []byte
+	KeyType   string
+	FileType  string
+}
+
+func (k *KeyInfo) String() string {
+	return fmt.Sprintf("%s (%s)", lib.HexEncode(k.PublicKey, lib.HexEncodeLowerColon), k.KeyType)
+}
+
+func (k *KeyInfo) SKI(displayMode lib.HexEncodeMode) (string, error) {
+	var subPKI subjectPublicKeyInfo
+
+	_, err := asn1.Unmarshal(k.PublicKey, &subPKI)
+	if err != nil {
+		return "", fmt.Errorf("serializing SKI: %w", err)
+	}
+
+	pubHash := sha1.Sum(subPKI.SubjectPublicKey.Bytes) // #nosec G401 this is the standard
+	pubHashString := lib.HexEncode(pubHash[:], displayMode)
+
+	return pubHashString, nil
+}
+
+// ParsePEM parses a PEM file and returns the public key and its type.
+func ParsePEM(path string) (*KeyInfo, error) {
+	material := &KeyInfo{}
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("parsing X.509 material %s: %w", path, err)
+	}
+
+	data = bytes.TrimSpace(data)
+	p, rest := pem.Decode(data)
+	if len(rest) > 0 {
+		lib.Warnx("trailing data in PEM file")
+	}
+
+	if p == nil {
+		return nil, fmt.Errorf("no PEM data in %s", path)
+	}
+
+	data = p.Bytes
+
+	switch p.Type {
+	case "PRIVATE KEY", "RSA PRIVATE KEY", "EC PRIVATE KEY":
+		material.PublicKey, material.KeyType = parseKey(data)
+		material.FileType = "private key"
+	case "CERTIFICATE":
+		material.PublicKey, material.KeyType = parseCertificate(data)
+		material.FileType = "certificate"
+	case "CERTIFICATE REQUEST":
+		material.PublicKey, material.KeyType = parseCSR(data)
+		material.FileType = "certificate request"
+	default:
+		return nil, fmt.Errorf("unknown PEM type %s", p.Type)
+	}
+
+	return material, nil
+}
+
+func parseKey(data []byte) ([]byte, string) {
+	priv, err := certlib.ParsePrivateKeyDER(data)
+	if err != nil {
+		die.If(err)
+	}
+
+	var kt string
+	switch priv.Public().(type) {
+	case *rsa.PublicKey:
+		kt = keyTypeRSA
+	case *ecdsa.PublicKey:
+		kt = keyTypeECDSA
+	default:
+		die.With("unknown private key type %T", priv)
+	}
+
+	public, err := x509.MarshalPKIXPublicKey(priv.Public())
+	die.If(err)
+
+	return public, kt
+}
+
+func parseCertificate(data []byte) ([]byte, string) {
+	cert, err := x509.ParseCertificate(data)
+	die.If(err)
+
+	pub := cert.PublicKey
+	var kt string
+	switch pub.(type) {
+	case *rsa.PublicKey:
+		kt = keyTypeRSA
+	case *ecdsa.PublicKey:
+		kt = keyTypeECDSA
+	case *ed25519.PublicKey:
+		kt = keyTypeEd25519
+	default:
+		die.With("unknown public key type %T", pub)
+	}
+
+	public, err := x509.MarshalPKIXPublicKey(pub)
+	die.If(err)
+	return public, kt
+}
+
+func parseCSR(data []byte) ([]byte, string) {
+	// Use certlib to support both PEM and DER and to centralize validation.
+	csr, _, err := certlib.ParseCSR(data)
+	die.If(err)
+
+	pub := csr.PublicKey
+	var kt string
+	switch pub.(type) {
+	case *rsa.PublicKey:
+		kt = keyTypeRSA
+	case *ecdsa.PublicKey:
+		kt = keyTypeECDSA
+	default:
+		die.With("unknown public key type %T", pub)
+	}
+
+	public, err := x509.MarshalPKIXPublicKey(pub)
+	die.If(err)
+	return public, kt
+}

certlib/verify/check.go

@@ -0,0 +1,49 @@
+package verify
+
+import (
+	"crypto/x509"
+	"fmt"
+	"time"
+
+	"git.wntrmute.dev/kyle/goutils/certlib/dump"
+)
+
+const DefaultLeeway = 2160 * time.Hour // three months
+
+type CertCheck struct {
+	Cert   *x509.Certificate
+	leeway time.Duration
+}
+
+func NewCertCheck(cert *x509.Certificate, leeway time.Duration) *CertCheck {
+	return &CertCheck{
+		Cert:   cert,
+		leeway: leeway,
+	}
+}
+
+func (c CertCheck) Expiry() time.Duration {
+	return time.Until(c.Cert.NotAfter)
+}
+
+func (c CertCheck) IsExpiring(leeway time.Duration) bool {
+	return c.Expiry() < leeway
+}
+
+// Err returns nil if the certificate is not expiring within the leeway period.
+func (c CertCheck) Err() error {
+	if !c.IsExpiring(c.leeway) {
+		return nil
+	}
+
+	return fmt.Errorf("%s expires in %s", dump.DisplayName(c.Cert.Subject), c.Expiry())
+}
+
+func (c CertCheck) Name() string {
+	return fmt.Sprintf("%s/SN=%s", dump.DisplayName(c.Cert.Subject),
+		c.Cert.SerialNumber)
+}
+
+func (c CertCheck) String() string {
+	return fmt.Sprintf("%s expires on %s (in %s)\n", c.Name(), c.Cert.NotAfter, c.Expiry())
+}

certlib/verify/verify.go

@@ -0,0 +1,143 @@
+package verify
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"io"
+
+	"git.wntrmute.dev/kyle/goutils/certlib/revoke"
+	"git.wntrmute.dev/kyle/goutils/lib"
+)
+
+func bundleIntermediates(w io.Writer, chain []*x509.Certificate, pool *x509.CertPool, verbose bool) *x509.CertPool {
+	for _, intermediate := range chain[1:] {
+		if verbose {
+			fmt.Fprintf(w, "[+] adding intermediate with SKI %x\n", intermediate.SubjectKeyId)
+		}
+		pool.AddCert(intermediate)
+	}
+
+	return pool
+}
+
+type Opts struct {
+	Verbose            bool
+	Config             *tls.Config
+	Intermediates      *x509.CertPool
+	ForceIntermediates bool
+	CheckRevocation    bool
+	KeyUsages          []x509.ExtKeyUsage
+}
+
+type verifyResult struct {
+	chain []*x509.Certificate
+	roots *x509.CertPool
+	ints  *x509.CertPool
+}
+
+func prepareVerification(w io.Writer, target string, opts *Opts) (*verifyResult, error) {
+	var (
+		roots, ints *x509.CertPool
+		err         error
+	)
+
+	if opts == nil {
+		opts = &Opts{
+			Config:             lib.StrictBaselineTLSConfig(),
+			ForceIntermediates: false,
+		}
+	}
+
+	if opts.Config.RootCAs == nil {
+		roots, err = x509.SystemCertPool()
+		if err != nil {
+			return nil, fmt.Errorf("couldn't load system cert pool: %w", err)
+		}
+
+		opts.Config.RootCAs = roots
+	}
+
+	if opts.Intermediates == nil {
+		ints = x509.NewCertPool()
+	} else {
+		ints = opts.Intermediates.Clone()
+	}
+
+	roots = opts.Config.RootCAs.Clone()
+
+	chain, err := lib.GetCertificateChain(target, opts.Config)
+	if err != nil {
+		return nil, fmt.Errorf("fetching certificate chain: %w", err)
+	}
+
+	if opts.Verbose {
+		fmt.Fprintf(w, "[+] %s has %d certificates\n", target, len(chain))
+	}
+
+	if len(chain) > 1 && opts.ForceIntermediates {
+		ints = bundleIntermediates(w, chain, ints, opts.Verbose)
+	}
+
+	return &verifyResult{
+		chain: chain,
+		roots: roots,
+		ints:  ints,
+	}, nil
+}
+
+// Chain fetches the certificate chain for a target and verifies it.
+func Chain(w io.Writer, target string, opts *Opts) ([]*x509.Certificate, error) {
+	result, err := prepareVerification(w, target, opts)
+	if err != nil {
+		return nil, fmt.Errorf("certificate verification failed: %w", err)
+	}
+
+	chains, err := CertWith(result.chain[0], result.roots, result.ints, opts.CheckRevocation, opts.KeyUsages...)
+	if err != nil {
+		return nil, fmt.Errorf("certificate verification failed: %w", err)
+	}
+
+	return chains, nil
+}
+
+// CertWith verifies a certificate against a set of roots and intermediates.
+func CertWith(
+	cert *x509.Certificate,
+	roots, ints *x509.CertPool,
+	checkRevocation bool,
+	keyUses ...x509.ExtKeyUsage,
+) ([]*x509.Certificate, error) {
+	if len(keyUses) == 0 {
+		keyUses = []x509.ExtKeyUsage{x509.ExtKeyUsageAny}
+	}
+
+	opts := x509.VerifyOptions{
+		Intermediates: ints,
+		Roots:         roots,
+		KeyUsages:     keyUses,
+	}
+
+	chains, err := cert.Verify(opts)
+	if err != nil {
+		return nil, err
+	}
+
+	if checkRevocation {
+		revoked, ok := revoke.VerifyCertificate(cert)
+		if !ok {
+			return nil, errors.New("failed to check certificate revocation status")
+		}
+
+		if revoked {
+			return nil, errors.New("certificate is revoked")
+		}
+	}
+
+	if len(chains) == 0 {
+		return nil, errors.New("no valid certificate chain found")
+	}
+
+	return chains[0], nil
+}

cmd/ca-signed/main.go

@@ -1,157 +1,22 @@
 package main
 
 import (
+	"bytes"
 	"crypto/x509"
 	"embed"
-	"errors"
+	"flag"
 	"fmt"
 	"os"
-	"path/filepath"
-	"time"
 
 	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/verify"
+	"git.wntrmute.dev/kyle/goutils/die"
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-// loadCertsFromFile attempts to parse certificates from a file that may be in
-// PEM or DER/PKCS#7 format. Returns the parsed certificates or an error.
-func loadCertsFromFile(path string) ([]*x509.Certificate, error) {
-	var certs []*x509.Certificate
-
-	data, err := os.ReadFile(path)
-	if err != nil {
-		return nil, err
-	}
-
-	if certs, err = certlib.ParseCertificatesPEM(data); err == nil {
-		return certs, nil
-	}
-
-	if certs, _, err = certlib.ParseCertificatesDER(data, ""); err == nil {
-		return certs, nil
-	}
-
-	return nil, err
-}
-
-func makePoolFromFile(path string) (*x509.CertPool, error) {
-	// Try PEM via helper (it builds a pool)
-	if pool, err := certlib.LoadPEMCertPool(path); err == nil && pool != nil {
-		return pool, nil
-	}
-
-	// Fallback: read as DER(s), add to a new pool
-	certs, err := loadCertsFromFile(path)
-	if err != nil || len(certs) == 0 {
-		return nil, fmt.Errorf("failed to load CA certificates from %s", path)
-	}
-	pool := x509.NewCertPool()
-	for _, c := range certs {
-		pool.AddCert(c)
-	}
-	return pool, nil
-}
-
 //go:embed testdata/*.pem
 var embeddedTestdata embed.FS
 
-// loadCertsFromBytes attempts to parse certificates from bytes that may be in
-// PEM or DER/PKCS#7 format.
-func loadCertsFromBytes(data []byte) ([]*x509.Certificate, error) {
-	certs, err := certlib.ParseCertificatesPEM(data)
-	if err == nil {
-		return certs, nil
-	}
-
-	certs, _, err = certlib.ParseCertificatesDER(data, "")
-	if err == nil {
-		return certs, nil
-	}
-
-	return nil, err
-}
-
-func makePoolFromBytes(data []byte) (*x509.CertPool, error) {
-	certs, err := loadCertsFromBytes(data)
-	if err != nil || len(certs) == 0 {
-		return nil, errors.New("failed to load CA certificates from embedded bytes")
-	}
-	pool := x509.NewCertPool()
-	for _, c := range certs {
-		pool.AddCert(c)
-	}
-	return pool, nil
-}
-
-// isSelfSigned returns true if the given certificate is self-signed.
-// It checks that the subject and issuer match and that the certificate's
-// signature verifies against its own public key.
-func isSelfSigned(cert *x509.Certificate) bool {
-	if cert == nil {
-		return false
-	}
-	// Quick check: subject and issuer match
-	if cert.Subject.String() != cert.Issuer.String() {
-		return false
-	}
-	// Cryptographic check: the certificate is signed by itself
-	if err := cert.CheckSignatureFrom(cert); err != nil {
-		return false
-	}
-	return true
-}
-
-func verifyAgainstCA(caPool *x509.CertPool, path string) (bool, string) {
-	certs, err := loadCertsFromFile(path)
-	if err != nil || len(certs) == 0 {
-		return false, ""
-	}
-
-	leaf := certs[0]
-	ints := x509.NewCertPool()
-	if len(certs) > 1 {
-		for _, ic := range certs[1:] {
-			ints.AddCert(ic)
-		}
-	}
-
-	opts := x509.VerifyOptions{
-		Roots:         caPool,
-		Intermediates: ints,
-		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
-	}
-	if _, err = leaf.Verify(opts); err != nil {
-		return false, ""
-	}
-
-	return true, leaf.NotAfter.Format("2006-01-02")
-}
-
-func verifyAgainstCABytes(caPool *x509.CertPool, certData []byte) (bool, string) {
-	certs, err := loadCertsFromBytes(certData)
-	if err != nil || len(certs) == 0 {
-		return false, ""
-	}
-
-	leaf := certs[0]
-	ints := x509.NewCertPool()
-	if len(certs) > 1 {
-		for _, ic := range certs[1:] {
-			ints.AddCert(ic)
-		}
-	}
-
-	opts := x509.VerifyOptions{
-		Roots:         caPool,
-		Intermediates: ints,
-		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
-	}
-	if _, err = leaf.Verify(opts); err != nil {
-		return false, ""
-	}
-
-	return true, leaf.NotAfter.Format("2006-01-02")
-}
-
 type testCase struct {
 	name     string
 	caFile   string
@@ -170,18 +35,25 @@ func (tc testCase) Run() error {
 		return fmt.Errorf("selftest: failed to read embedded %s: %w", tc.certFile, err)
 	}
 
-	pool, err := makePoolFromBytes(caBytes)
+	pool, err := certlib.PoolFromBytes(caBytes)
 	if err != nil || pool == nil {
 		return fmt.Errorf("selftest: failed to build CA pool for %s: %w", tc.caFile, err)
 	}
 
-	ok, exp := verifyAgainstCABytes(pool, certBytes)
+	cert, _, err := certlib.ReadCertificate(certBytes)
+	if err != nil {
+		return fmt.Errorf("selftest: failed to parse certificate from %s: %w", tc.certFile, err)
+	}
+
+	_, err = verify.CertWith(cert, pool, nil, false)
+	ok := err == nil
+
 	if ok != tc.expectOK {
 		return fmt.Errorf("%s: unexpected result: got %v, want %v", tc.name, ok, tc.expectOK)
 	}
 
 	if ok {
-		fmt.Printf("%s: OK (expires %s)\n", tc.name, exp)
+		fmt.Printf("%s: OK (expires %s)\n", tc.name, cert.NotAfter.Format(lib.DateShortFormat))
 	}
 
 	fmt.Printf("%s: INVALID (as expected)\n", tc.name)
@@ -237,14 +109,16 @@ func selftest() int {
 			failures++
 			continue
 		}
-		certs, err := loadCertsFromBytes(b)
+
+		certs, err := certlib.ReadCertificates(b)
 		if err != nil || len(certs) == 0 {
 			fmt.Fprintf(os.Stderr, "selftest: failed to parse cert(s) from %s: %v\n", root, err)
 			failures++
 			continue
 		}
+
 		leaf := certs[0]
-		if isSelfSigned(leaf) {
+		if len(leaf.AuthorityKeyId) == 0 || bytes.Equal(leaf.AuthorityKeyId, leaf.SubjectKeyId) {
 			fmt.Printf("%s: SELF-SIGNED (as expected)\n", root)
 		} else {
 			fmt.Printf("%s: expected SELF-SIGNED, but was not detected as such\n", root)
@@ -260,66 +134,58 @@ func selftest() int {
 	return 1
 }
 
-// expiryString returns a YYYY-MM-DD date string to display for certificate
-// expiry. If an explicit exp string is provided, it is used. Otherwise, if a
-// leaf certificate is available, its NotAfter is formatted. As a last resort,
-// it falls back to today's date (should not normally happen).
-func expiryString(leaf *x509.Certificate, exp string) string {
-	if exp != "" {
-		return exp
-	}
-	if leaf != nil {
-		return leaf.NotAfter.Format("2006-01-02")
-	}
-	return time.Now().Format("2006-01-02")
-}
-
-// processCert verifies a single certificate file against the provided CA pool
-// and prints the result in the required format, handling self-signed
-// certificates specially.
-func processCert(caPool *x509.CertPool, certPath string) {
-	ok, exp := verifyAgainstCA(caPool, certPath)
-	name := filepath.Base(certPath)
-
-	// Try to load the leaf cert for self-signed detection and expiry fallback
-	var leaf *x509.Certificate
-	if certs, err := loadCertsFromFile(certPath); err == nil && len(certs) > 0 {
-		leaf = certs[0]
-	}
-
-	// Prefer the SELF-SIGNED label if applicable
-	if isSelfSigned(leaf) {
-		fmt.Printf("%s: SELF-SIGNED\n", name)
-		return
-	}
-
-	if ok {
-		fmt.Printf("%s: OK (expires %s)\n", name, expiryString(leaf, exp))
-		return
-	}
-	fmt.Printf("%s: INVALID\n", name)
-}
-
 func main() {
-	// Special selftest mode: single argument "selftest"
-	if len(os.Args) == 2 && os.Args[1] == "selftest" {
+	var skipVerify, useStrict bool
+
+	lib.StrictTLSFlag(&useStrict)
+	flag.BoolVar(&skipVerify, "k", false, "don't verify certificates")
+	flag.Parse()
+
+	tcfg, err := lib.BaselineTLSConfig(skipVerify, useStrict)
+	die.If(err)
+
+	args := flag.Args()
+
+	if len(args) == 1 && args[0] == "selftest" {
 		os.Exit(selftest())
 	}
 
-	if len(os.Args) < 3 {
-		prog := filepath.Base(os.Args[0])
-		fmt.Fprintf(os.Stderr, "Usage:\n  %s ca.pem cert1.pem cert2.pem ...\n  %s selftest\n", prog, prog)
-		os.Exit(2)
-	}
-
-	caPath := os.Args[1]
-	caPool, err := makePoolFromFile(caPath)
-	if err != nil || caPool == nil {
-		fmt.Fprintf(os.Stderr, "failed to load CA certificate(s): %v\n", err)
+	if len(args) < 2 {
+		fmt.Println("No certificates to check.")
 		os.Exit(1)
 	}
 
-	for _, certPath := range os.Args[2:] {
-		processCert(caPool, certPath)
+	caFile := args[0]
+	args = args[1:]
+
+	caCert, err := certlib.LoadCertificates(caFile)
+	die.If(err)
+
+	if len(caCert) != 1 {
+		die.With("only one CA certificate should be presented.")
+	}
+
+	roots := x509.NewCertPool()
+	roots.AddCert(caCert[0])
+
+	for _, arg := range args {
+		var cert *x509.Certificate
+
+		cert, err = lib.GetCertificate(arg, tcfg)
+		if err != nil {
+			lib.Warn(err, "while parsing certificate from %s", arg)
+			continue
+		}
+
+		if bytes.Equal(cert.AuthorityKeyId, caCert[0].AuthorityKeyId) {
+			fmt.Printf("%s: SELF-SIGNED\n", arg)
+			continue
+		}
+
+		if _, err = verify.CertWith(cert, roots, nil, false); err != nil {
+			fmt.Printf("%s: INVALID\n", arg)
+		} else {
+			fmt.Printf("%s: OK (expires %s)\n", arg, cert.NotAfter.Format(lib.DateShortFormat))
+		}
 	}
 }

cmd/cert-bundler/Dockerfile

@@ -0,0 +1,28 @@
+# Build and runtime image for cert-bundler
+# Usage (from repo root or cmd/cert-bundler directory):
+#   docker build -t cert-bundler:latest -f cmd/cert-bundler/Dockerfile .
+#   docker run --rm -v "$PWD":/work cert-bundler:latest
+# This expects a /work/bundle.yaml file in the mounted directory and
+# will write generated bundles to /work/bundle.
+
+# Build stage
+FROM golang:1.24.3-alpine AS build
+WORKDIR /src
+
+# Copy go module files and download dependencies first for better caching
+RUN go install git.wntrmute.dev/kyle/goutils/cmd/cert-bundler@v1.13.2 && \
+    mv /go/bin/cert-bundler /usr/local/bin/cert-bundler
+
+# Runtime stage (kept as golang:alpine per requirement)
+FROM golang:1.24.3-alpine
+
+# Create a work directory that users will typically mount into
+WORKDIR /work
+VOLUME ["/work"]
+
+# Copy the built binary from the builder stage
+COPY --from=build /usr/local/bin/cert-bundler /usr/local/bin/cert-bundler
+
+# Default command: read bundle.yaml from current directory and output to ./bundle
+ENTRYPOINT ["/usr/local/bin/cert-bundler"]
+CMD ["-c", "/work/bundle.yaml", "-o", "/work/bundle"]

cmd/cert-bundler/main.go

@@ -1,66 +1,19 @@
 package main
 
 import (
-	"archive/tar"
-	"archive/zip"
-	"compress/gzip"
-	"crypto/sha256"
-	"crypto/x509"
 	_ "embed"
-	"encoding/pem"
-	"errors"
 	"flag"
 	"fmt"
-	"io"
 	"os"
-	"path/filepath"
-	"strings"
-	"time"
 
-	"git.wntrmute.dev/kyle/goutils/certlib"
-	"gopkg.in/yaml.v2"
+	"git.wntrmute.dev/kyle/goutils/certlib/bundler"
 )
 
-// Config represents the top-level YAML configuration.
-type Config struct {
-	Config struct {
-		Hashes string `yaml:"hashes"`
-		Expiry string `yaml:"expiry"`
-	} `yaml:"config"`
-	Chains map[string]ChainGroup `yaml:"chains"`
-}
-
-// ChainGroup represents a named group of certificate chains.
-type ChainGroup struct {
-	Certs   []CertChain `yaml:"certs"`
-	Outputs Outputs     `yaml:"outputs"`
-}
-
-// CertChain represents a root certificate and its intermediates.
-type CertChain struct {
-	Root          string   `yaml:"root"`
-	Intermediates []string `yaml:"intermediates"`
-}
-
-// Outputs defines output format options.
-type Outputs struct {
-	IncludeSingle     bool     `yaml:"include_single"`
-	IncludeIndividual bool     `yaml:"include_individual"`
-	Manifest          bool     `yaml:"manifest"`
-	Formats           []string `yaml:"formats"`
-	Encoding          string   `yaml:"encoding"`
-}
-
 var (
 	configFile string
 	outputDir  string
 )
 
-var formatExtensions = map[string]string{
-	"zip": ".zip",
-	"tgz": ".tar.gz",
-}
-
 //go:embed README.txt
 var readmeContent string
 
@@ -79,497 +32,10 @@ func main() {
 		os.Exit(1)
 	}
 
-	// Load and parse configuration
-	cfg, err := loadConfig(configFile)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
+	if err := bundler.Run(configFile, outputDir); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
 		os.Exit(1)
 	}
 
-	// Parse expiry duration (default 1 year)
-	expiryDuration := 365 * 24 * time.Hour
-	if cfg.Config.Expiry != "" {
-		expiryDuration, err = parseDuration(cfg.Config.Expiry)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "Error parsing expiry: %v\n", err)
-			os.Exit(1)
-		}
-	}
-
-	// Create output directory if it doesn't exist
-	err = os.MkdirAll(outputDir, 0750)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Error creating output directory: %v\n", err)
-		os.Exit(1)
-	}
-
-	// Process each chain group
-	// Pre-allocate createdFiles based on total number of formats across all groups
-	totalFormats := 0
-	for _, group := range cfg.Chains {
-		totalFormats += len(group.Outputs.Formats)
-	}
-	createdFiles := make([]string, 0, totalFormats)
-	for groupName, group := range cfg.Chains {
-		files, perr := processChainGroup(groupName, group, expiryDuration)
-		if perr != nil {
-			fmt.Fprintf(os.Stderr, "Error processing chain group %s: %v\n", groupName, perr)
-			os.Exit(1)
-		}
-		createdFiles = append(createdFiles, files...)
-	}
-
-	// Generate hash file for all created archives
-	if cfg.Config.Hashes != "" {
-		hashFile := filepath.Join(outputDir, cfg.Config.Hashes)
-		if gerr := generateHashFile(hashFile, createdFiles); gerr != nil {
-			fmt.Fprintf(os.Stderr, "Error generating hash file: %v\n", gerr)
-			os.Exit(1)
-		}
-	}
-
 	fmt.Println("Certificate bundling completed successfully")
 }
-
-func loadConfig(path string) (*Config, error) {
-	data, err := os.ReadFile(path)
-	if err != nil {
-		return nil, err
-	}
-
-	var cfg Config
-	if uerr := yaml.Unmarshal(data, &cfg); uerr != nil {
-		return nil, uerr
-	}
-
-	return &cfg, nil
-}
-
-func parseDuration(s string) (time.Duration, error) {
-	// Support simple formats like "1y", "6m", "30d"
-	if len(s) < 2 {
-		return 0, fmt.Errorf("invalid duration format: %s", s)
-	}
-
-	unit := s[len(s)-1]
-	value := s[:len(s)-1]
-
-	var multiplier time.Duration
-	switch unit {
-	case 'y', 'Y':
-		multiplier = 365 * 24 * time.Hour
-	case 'm', 'M':
-		multiplier = 30 * 24 * time.Hour
-	case 'd', 'D':
-		multiplier = 24 * time.Hour
-	default:
-		return time.ParseDuration(s)
-	}
-
-	var num int
-	_, err := fmt.Sscanf(value, "%d", &num)
-	if err != nil {
-		return 0, fmt.Errorf("invalid duration value: %s", s)
-	}
-
-	return time.Duration(num) * multiplier, nil
-}
-
-func processChainGroup(groupName string, group ChainGroup, expiryDuration time.Duration) ([]string, error) {
-	// Default encoding to "pem" if not specified
-	encoding := group.Outputs.Encoding
-	if encoding == "" {
-		encoding = "pem"
-	}
-
-	// Collect certificates from all chains in the group
-	singleFileCerts, individualCerts, err := loadAndCollectCerts(group.Certs, group.Outputs, expiryDuration)
-	if err != nil {
-		return nil, err
-	}
-
-	// Prepare files for inclusion in archives
-	archiveFiles, err := prepareArchiveFiles(singleFileCerts, individualCerts, group.Outputs, encoding)
-	if err != nil {
-		return nil, err
-	}
-
-	// Create archives for the entire group
-	createdFiles, err := createArchiveFiles(groupName, group.Outputs.Formats, archiveFiles)
-	if err != nil {
-		return nil, err
-	}
-
-	return createdFiles, nil
-}
-
-// loadAndCollectCerts loads all certificates from chains and collects them for processing.
-func loadAndCollectCerts(
-	chains []CertChain,
-	outputs Outputs,
-	expiryDuration time.Duration,
-) ([]*x509.Certificate, []certWithPath, error) {
-	var singleFileCerts []*x509.Certificate
-	var individualCerts []certWithPath
-
-	for _, chain := range chains {
-		s, i, cerr := collectFromChain(chain, outputs, expiryDuration)
-		if cerr != nil {
-			return nil, nil, cerr
-		}
-		if len(s) > 0 {
-			singleFileCerts = append(singleFileCerts, s...)
-		}
-		if len(i) > 0 {
-			individualCerts = append(individualCerts, i...)
-		}
-	}
-
-	return singleFileCerts, individualCerts, nil
-}
-
-// collectFromChain loads a single chain, performs checks, and returns the certs to include.
-func collectFromChain(
-	chain CertChain,
-	outputs Outputs,
-	expiryDuration time.Duration,
-) (
-	[]*x509.Certificate,
-	[]certWithPath,
-	error,
-) {
-	var single []*x509.Certificate
-	var indiv []certWithPath
-
-	// Load root certificate
-	rootCert, rerr := certlib.LoadCertificate(chain.Root)
-	if rerr != nil {
-		return nil, nil, fmt.Errorf("failed to load root certificate %s: %w", chain.Root, rerr)
-	}
-
-	// Check expiry for root
-	checkExpiry(chain.Root, rootCert, expiryDuration)
-
-	// Add root to collections if needed
-	if outputs.IncludeSingle {
-		single = append(single, rootCert)
-	}
-	if outputs.IncludeIndividual {
-		indiv = append(indiv, certWithPath{cert: rootCert, path: chain.Root})
-	}
-
-	// Load and validate intermediates
-	for _, intPath := range chain.Intermediates {
-		intCert, lerr := certlib.LoadCertificate(intPath)
-		if lerr != nil {
-			return nil, nil, fmt.Errorf("failed to load intermediate certificate %s: %w", intPath, lerr)
-		}
-
-		// Validate that intermediate is signed by root
-		if sigErr := intCert.CheckSignatureFrom(rootCert); sigErr != nil {
-			return nil, nil, fmt.Errorf(
-				"intermediate %s is not properly signed by root %s: %w",
-				intPath,
-				chain.Root,
-				sigErr,
-			)
-		}
-
-		// Check expiry for intermediate
-		checkExpiry(intPath, intCert, expiryDuration)
-
-		// Add intermediate to collections if needed
-		if outputs.IncludeSingle {
-			single = append(single, intCert)
-		}
-		if outputs.IncludeIndividual {
-			indiv = append(indiv, certWithPath{cert: intCert, path: intPath})
-		}
-	}
-
-	return single, indiv, nil
-}
-
-// prepareArchiveFiles prepares all files to be included in archives.
-func prepareArchiveFiles(
-	singleFileCerts []*x509.Certificate,
-	individualCerts []certWithPath,
-	outputs Outputs,
-	encoding string,
-) ([]fileEntry, error) {
-	var archiveFiles []fileEntry
-
-	// Handle a single bundle file
-	if outputs.IncludeSingle && len(singleFileCerts) > 0 {
-		files, err := encodeCertsToFiles(singleFileCerts, "bundle", encoding, true)
-		if err != nil {
-			return nil, fmt.Errorf("failed to encode single bundle: %w", err)
-		}
-		archiveFiles = append(archiveFiles, files...)
-	}
-
-	// Handle individual files
-	if outputs.IncludeIndividual {
-		for _, cp := range individualCerts {
-			baseName := strings.TrimSuffix(filepath.Base(cp.path), filepath.Ext(cp.path))
-			files, err := encodeCertsToFiles([]*x509.Certificate{cp.cert}, baseName, encoding, false)
-			if err != nil {
-				return nil, fmt.Errorf("failed to encode individual cert %s: %w", cp.path, err)
-			}
-			archiveFiles = append(archiveFiles, files...)
-		}
-	}
-
-	// Generate manifest if requested
-	if outputs.Manifest {
-		manifestContent := generateManifest(archiveFiles)
-		archiveFiles = append(archiveFiles, fileEntry{
-			name:    "MANIFEST",
-			content: manifestContent,
-		})
-	}
-
-	return archiveFiles, nil
-}
-
-// createArchiveFiles creates archive files in the specified formats.
-func createArchiveFiles(groupName string, formats []string, archiveFiles []fileEntry) ([]string, error) {
-	createdFiles := make([]string, 0, len(formats))
-
-	for _, format := range formats {
-		ext, ok := formatExtensions[format]
-		if !ok {
-			return nil, fmt.Errorf("unsupported format: %s", format)
-		}
-		archivePath := filepath.Join(outputDir, groupName+ext)
-		switch format {
-		case "zip":
-			if err := createZipArchive(archivePath, archiveFiles); err != nil {
-				return nil, fmt.Errorf("failed to create zip archive: %w", err)
-			}
-		case "tgz":
-			if err := createTarGzArchive(archivePath, archiveFiles); err != nil {
-				return nil, fmt.Errorf("failed to create tar.gz archive: %w", err)
-			}
-		default:
-			return nil, fmt.Errorf("unsupported format: %s", format)
-		}
-		createdFiles = append(createdFiles, archivePath)
-	}
-
-	return createdFiles, nil
-}
-
-func checkExpiry(path string, cert *x509.Certificate, expiryDuration time.Duration) {
-	now := time.Now()
-	expiryThreshold := now.Add(expiryDuration)
-
-	if cert.NotAfter.Before(expiryThreshold) {
-		daysUntilExpiry := int(cert.NotAfter.Sub(now).Hours() / 24)
-		if daysUntilExpiry < 0 {
-			fmt.Fprintf(
-				os.Stderr,
-				"WARNING: Certificate %s has EXPIRED (expired %d days ago)\n",
-				path,
-				-daysUntilExpiry,
-			)
-		} else {
-			fmt.Fprintf(os.Stderr, "WARNING: Certificate %s will expire in %d days (on %s)\n", path, daysUntilExpiry, cert.NotAfter.Format("2006-01-02"))
-		}
-	}
-}
-
-type fileEntry struct {
-	name    string
-	content []byte
-}
-
-type certWithPath struct {
-	cert *x509.Certificate
-	path string
-}
-
-// encodeCertsToFiles converts certificates to file entries based on encoding type
-// If isSingle is true, certs are concatenated into a single file; otherwise one cert per file.
-func encodeCertsToFiles(
-	certs []*x509.Certificate,
-	baseName string,
-	encoding string,
-	isSingle bool,
-) ([]fileEntry, error) {
-	var files []fileEntry
-
-	switch encoding {
-	case "pem":
-		pemContent := encodeCertsToPEM(certs)
-		files = append(files, fileEntry{
-			name:    baseName + ".pem",
-			content: pemContent,
-		})
-	case "der":
-		if isSingle {
-			// For single file in DER, concatenate all cert DER bytes
-			var derContent []byte
-			for _, cert := range certs {
-				derContent = append(derContent, cert.Raw...)
-			}
-			files = append(files, fileEntry{
-				name:    baseName + ".crt",
-				content: derContent,
-			})
-		} else if len(certs) > 0 {
-			// Individual DER file (should only have one cert)
-			files = append(files, fileEntry{
-				name:    baseName + ".crt",
-				content: certs[0].Raw,
-			})
-		}
-	case "both":
-		// Add PEM version
-		pemContent := encodeCertsToPEM(certs)
-		files = append(files, fileEntry{
-			name:    baseName + ".pem",
-			content: pemContent,
-		})
-		// Add DER version
-		if isSingle {
-			var derContent []byte
-			for _, cert := range certs {
-				derContent = append(derContent, cert.Raw...)
-			}
-			files = append(files, fileEntry{
-				name:    baseName + ".crt",
-				content: derContent,
-			})
-		} else if len(certs) > 0 {
-			files = append(files, fileEntry{
-				name:    baseName + ".crt",
-				content: certs[0].Raw,
-			})
-		}
-	default:
-		return nil, fmt.Errorf("unsupported encoding: %s (must be 'pem', 'der', or 'both')", encoding)
-	}
-
-	return files, nil
-}
-
-// encodeCertsToPEM encodes certificates to PEM format.
-func encodeCertsToPEM(certs []*x509.Certificate) []byte {
-	var pemContent []byte
-	for _, cert := range certs {
-		pemBlock := &pem.Block{
-			Type:  "CERTIFICATE",
-			Bytes: cert.Raw,
-		}
-		pemContent = append(pemContent, pem.EncodeToMemory(pemBlock)...)
-	}
-	return pemContent
-}
-
-func generateManifest(files []fileEntry) []byte {
-	var manifest strings.Builder
-	for _, file := range files {
-		if file.name == "MANIFEST" {
-			continue
-		}
-		hash := sha256.Sum256(file.content)
-		manifest.WriteString(fmt.Sprintf("%x  %s\n", hash, file.name))
-	}
-	return []byte(manifest.String())
-}
-
-// closeWithErr attempts to close all provided closers, joining any close errors with baseErr.
-func closeWithErr(baseErr error, closers ...io.Closer) error {
-	for _, c := range closers {
-		if c == nil {
-			continue
-		}
-		if cerr := c.Close(); cerr != nil {
-			baseErr = errors.Join(baseErr, cerr)
-		}
-	}
-	return baseErr
-}
-
-func createZipArchive(path string, files []fileEntry) error {
-	f, zerr := os.Create(path)
-	if zerr != nil {
-		return zerr
-	}
-
-	w := zip.NewWriter(f)
-
-	for _, file := range files {
-		fw, werr := w.Create(file.name)
-		if werr != nil {
-			return closeWithErr(werr, w, f)
-		}
-		if _, werr = fw.Write(file.content); werr != nil {
-			return closeWithErr(werr, w, f)
-		}
-	}
-
-	// Check errors on close operations
-	if cerr := w.Close(); cerr != nil {
-		_ = f.Close()
-		return cerr
-	}
-	return f.Close()
-}
-
-func createTarGzArchive(path string, files []fileEntry) error {
-	f, terr := os.Create(path)
-	if terr != nil {
-		return terr
-	}
-
-	gw := gzip.NewWriter(f)
-	tw := tar.NewWriter(gw)
-
-	for _, file := range files {
-		hdr := &tar.Header{
-			Name: file.name,
-			Mode: 0644,
-			Size: int64(len(file.content)),
-		}
-		if herr := tw.WriteHeader(hdr); herr != nil {
-			return closeWithErr(herr, tw, gw, f)
-		}
-		if _, werr := tw.Write(file.content); werr != nil {
-			return closeWithErr(werr, tw, gw, f)
-		}
-	}
-
-	// Check errors on close operations in the correct order
-	if cerr := tw.Close(); cerr != nil {
-		_ = gw.Close()
-		_ = f.Close()
-		return cerr
-	}
-	if cerr := gw.Close(); cerr != nil {
-		_ = f.Close()
-		return cerr
-	}
-	return f.Close()
-}
-
-func generateHashFile(path string, files []string) error {
-	f, err := os.Create(path)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-
-	for _, file := range files {
-		data, rerr := os.ReadFile(file)
-		if rerr != nil {
-			return rerr
-		}
-
-		hash := sha256.Sum256(data)
-		fmt.Fprintf(f, "%x  %s\n", hash, filepath.Base(file))
-	}
-
-	return nil
-}

cmd/cert-bundler/prompt.txt

@@ -1,197 +0,0 @@
-This project is an exploration into the utility of Jetbrains' Junie
-to write smaller but tedious programs.
-
-Task: build a certificate bundling tool in cmd/cert-bundler. It
-creates archives of certificates chains.
-
-A YAML file for this looks something like:
-
-``` yaml
-config:
-  hashes: bundle.sha256
-  expiry: 1y
-chains:
-  core_certs:
-    certs:
-      - root: roots/core-ca.pem
-        intermediates:
-          - int/cca1.pem
-  	- int/cca2.pem
-  	- int/cca3.pem
-      - root: roots/ssh-ca.pem
-        intermediates:
-          - ssh/ssh_dmz1.pem
-  	- ssh/ssh_internal.pem
-  outputs:
-    include_single: true
-    include_individual: true
-    manifest: true
-    formats:
-      - zip
-      - tgz
-```
-
-Some requirements:
-
-1. First, all the certificates should be loaded.
-2. For each root, each of the indivudal intermediates should be
-   checked to make sure they are properly signed by the root CA.
-3. The program should optionally take an expiration period (defaulting
-   to one year), specified in config.expiration, and if any certificate
-   is within that expiration period, a warning should be printed.
-4. If outputs.include_single is true, all certificates under chains
-   should be concatenated into a single file.
-5. If outputs.include_individual is true, all certificates under
-   chains should be included at the root level (e.g. int/cca2.pem
-   would be cca2.pem in the archive).
-6. If bundle.manifest is true, a "MANIFEST" file is created with
-   SHA256 sums of each file included in the archive.
-7. For each of the formats, create an archive file in the output
-   directory (specified with `-o`) with that format.
-   - If zip is included, create a .zip file.
-   - If tgz is included, create a .tar.gz file with default compression
-     levels.
-   - All archive files should include any generated files (single
-     and/or individual) in the top-level directory.
-8. In the output directory, create a file with the same name as
-   config.hashes that contains the SHA256 sum of all files created.
-
------
-
-The outputs.include_single and outputs.include_individual describe
-what should go in the final archive. If both are specified, the output
-archive should include both a single bundle.pem and each individual
-certificate, for example.
-
------
-
-As it stands, given the following `bundle.yaml`:
-
-``` yaml
-config:
-  hashes: bundle.sha256
-  expiry: 1y
-chains:
-  core_certs:
-    certs:
-      - root: pems/gts-r1.pem
-        intermediates:
-          - pems/goog-wr2.pem
-        outputs:
-          include_single: true
-          include_individual: true
-          manifest: true
-          formats:
-            - zip
-            - tgz
-      - root: pems/isrg-root-x1.pem
-        intermediates:
-          - pems/le-e7.pem
-        outputs:
-          include_single: true
-          include_individual: false
-          manifest: true
-          formats:
-            - zip
-            - tgz
-  google_certs:
-    certs:
-      - root: pems/gts-r1.pem
-        intermediates:
-          - pems/goog-wr2.pem
-        outputs:
-          include_single: true
-          include_individual: false
-          manifest: true
-          formats:
-            - tgz
-  lets_encrypt:
-    certs:
-      - root: pems/isrg-root-x1.pem
-        intermediates:
-          - pems/le-e7.pem
-        outputs:
-          include_single: false
-          include_individual: true
-          manifest: false
-          formats:
-            - zip
-```
-
-The program outputs the following files:
-
-- bundle.sha256
-- core_certs_0.tgz (contains individual certs)
-- core_certs_0.zip (contains individual certs)
-- core_certs_1.tgz (contains core_certs.pem)
-- core_certs_1.zip (contains core_certs.pem)
-- google_certs_0.tgz
-- lets_encrypt_0.zip
-
-It should output
-
-- bundle.sha256
-- core_certs.tgz
-- core_certs.zip
-- google_certs.tgz
-- lets_encrypt.zip
-
-core_certs.* should contain `bundle.pem` and all the individual
-certs. There should be no _$n$ variants of archives.
-
------
-
-Add an additional field to outputs: encoding. It should accept one of
-`der`, `pem`, or `both`. If `der`, certificates should be output as a
-`.crt` file containing a DER-encoded certificate. If `pem`, certificates
-should be output as a `.pem` file containing a PEM-encoded certificate.
-If both, both the `.crt` and `.pem` certificate should be included.
-
-For example, given the previous config, if `encoding` is der, the
-google_certs.tgz archive should contain
-
-- bundle.crt
-- MANIFEST
-
-Or with lets_encrypt.zip:
-
-- isrg-root-x1.crt
-- le-e7.crt
-
-However, if `encoding` is pem, the lets_encrypt.zip archive should contain:
-
-- isrg-root-x1.pem
-- le-e7.pem
-
-And if it `encoding` is both, the lets_encrypt.zip archive should contain:
-
-- isrg-root-x1.crt
-- isrg-root-x1.pem
-- le-e7.crt
-- le-e7.pem
-
------
-
-The tgz format should output a `.tar.gz` file instead of a `.tgz` file.
-
------
-
-Move the format extensions to a global variable.
-
------
-
-Write a README.txt with a description of the bundle.yaml format.
-
-Additionally, update the help text for the program (e.g. with `-h`)
-to provide the same detailed information.
-
------
-
-It may be easier to embed the README.txt in the program on build.
-
------
-
-For the archive (tar.gz and zip) writers, make sure errors are
-checked at the end, and don't just defer the close operations.
-
-

cmd/cert-bundler/testdata/bundle.yaml

@@ -2,6 +2,19 @@ config:
   hashes: bundle.sha256
   expiry: 1y
 chains:
+  weird:
+    certs:
+      - root: pems/gts-r1.pem
+        intermediates:
+          - pems/goog-wr2.pem
+      - root: pems/isrg-root-x1.pem
+    outputs:
+      include_single: true
+      include_individual: true
+      manifest: true
+      formats:
+        - zip
+        - tgz
   core_certs:
     certs:
       - root: pems/gts-r1.pem

cmd/cert-bundler/testdata/pkg/bundle.sha256

@@ -1,4 +0,0 @@
-5ed8bf9ed693045faa8a5cb0edc4a870052e56aef6291ce8b1604565affbc2a4  core_certs.zip
-e59eddc590d2f7b790a87c5b56e81697088ab54be382c0e2c51b82034006d308  core_certs.tgz
-51b9b63b1335118079e90700a3a5b847c363808e9116e576ca84f301bc433289  google_certs.tgz
-3d1910ca8835c3ded1755a8c7d6c48083c2f3ff68b2bfbf932aaf27e29d0a232  lets_encrypt.zip

cmd/cert-revcheck/main.go

@@ -7,7 +7,6 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"net"
 	"os"
 	"strings"
 	"time"
@@ -16,6 +15,7 @@ import (
 	hosts "git.wntrmute.dev/kyle/goutils/certlib/hosts"
 	"git.wntrmute.dev/kyle/goutils/certlib/revoke"
 	"git.wntrmute.dev/kyle/goutils/fileutil"
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
 var (
@@ -38,8 +38,10 @@ func main() {
 	flag.Parse()
 
 	revoke.HardFail = hardfail
-	// Set HTTP client timeout for revocation library
-	revoke.HTTPClient.Timeout = timeout
+	// Build a proxy-aware HTTP client for OCSP/CRL fetches
+	if httpClient, err := lib.NewHTTPClient(lib.DialerOpts{Timeout: timeout}); err == nil {
+		revoke.HTTPClient = httpClient
+	}
 
 	if flag.NArg() == 0 {
 		fmt.Fprintf(os.Stderr, "Usage: %s [options] <target> [<target>...]\n", os.Args[0])
@@ -99,28 +101,19 @@ func checkSite(hostport string) (string, error) {
 		return strUnknown, err
 	}
 
-	d := &net.Dialer{Timeout: timeout}
-	tcfg := &tls.Config{
-		InsecureSkipVerify: true,
-		ServerName:         target.Host,
-	} // #nosec G402 -- CLI tool only verifies revocation
-	td := &tls.Dialer{NetDialer: d, Config: tcfg}
-
 	ctx, cancel := context.WithTimeout(context.Background(), timeout)
 	defer cancel()
 
-	conn, err := td.DialContext(ctx, "tcp", target.String())
+	// Use proxy-aware TLS dialer
+	conn, err := lib.DialTLS(ctx, target.String(), lib.DialerOpts{Timeout: timeout, TLSConfig: &tls.Config{
+		InsecureSkipVerify: true, // #nosec G402 -- CLI tool only verifies revocation
+		ServerName:         target.Host,
+	}})
 	if err != nil {
 		return strUnknown, err
 	}
 	defer conn.Close()
-
-	tconn, ok := conn.(*tls.Conn)
-	if !ok {
-		return strUnknown, errors.New("connection is not TLS")
-	}
-
-	state := tconn.ConnectionState()
+	state := conn.ConnectionState()
 	if len(state.PeerCertificates) == 0 {
 		return strUnknown, errors.New("no peer certificates presented")
 	}

cmd/certchain/main.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"git.wntrmute.dev/kyle/goutils/die"
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
 var hasPort = regexp.MustCompile(`:\d+$`)
@@ -23,13 +24,9 @@ func main() {
 			server += ":443"
 		}
 
-		d := &tls.Dialer{Config: &tls.Config{}} // #nosec G402
-		nc, err := d.DialContext(context.Background(), "tcp", server)
+		// Use proxy-aware TLS dialer
+		conn, err := lib.DialTLS(context.Background(), server, lib.DialerOpts{TLSConfig: &tls.Config{}}) // #nosec G402
 		die.If(err)
-		conn, ok := nc.(*tls.Conn)
-		if !ok {
-			die.With("invalid TLS connection (not a *tls.Conn)")
-		}
 
 		defer conn.Close()
 

cmd/certdump/main.go

@@ -2,364 +2,44 @@
 package main
 
 import (
-	"bytes"
-	"context"
-	"crypto/dsa"
-	"crypto/ecdsa"
-	"crypto/elliptic"
-	"crypto/rsa"
-	"crypto/sha256"
 	"crypto/tls"
-	"crypto/x509"
-	"crypto/x509/pkix"
 	"flag"
 	"fmt"
-	"io"
 	"os"
-	"sort"
-	"strings"
 
-	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/dump"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-func certPublic(cert *x509.Certificate) string {
-	switch pub := cert.PublicKey.(type) {
-	case *rsa.PublicKey:
-		return fmt.Sprintf("RSA-%d", pub.N.BitLen())
-	case *ecdsa.PublicKey:
-		switch pub.Curve {
-		case elliptic.P256():
-			return "ECDSA-prime256v1"
-		case elliptic.P384():
-			return "ECDSA-secp384r1"
-		case elliptic.P521():
-			return "ECDSA-secp521r1"
-		default:
-			return "ECDSA (unknown curve)"
-		}
-	case *dsa.PublicKey:
-		return "DSA"
-	default:
-		return "Unknown"
-	}
-}
-
-func displayName(name pkix.Name) string {
-	var ns []string
-
-	if name.CommonName != "" {
-		ns = append(ns, name.CommonName)
-	}
-
-	for i := range name.Country {
-		ns = append(ns, fmt.Sprintf("C=%s", name.Country[i]))
-	}
-
-	for i := range name.Organization {
-		ns = append(ns, fmt.Sprintf("O=%s", name.Organization[i]))
-	}
-
-	for i := range name.OrganizationalUnit {
-		ns = append(ns, fmt.Sprintf("OU=%s", name.OrganizationalUnit[i]))
-	}
-
-	for i := range name.Locality {
-		ns = append(ns, fmt.Sprintf("L=%s", name.Locality[i]))
-	}
-
-	for i := range name.Province {
-		ns = append(ns, fmt.Sprintf("ST=%s", name.Province[i]))
-	}
-
-	if len(ns) > 0 {
-		return "/" + strings.Join(ns, "/")
-	}
-
-	return "*** no subject information ***"
-}
-
-func keyUsages(ku x509.KeyUsage) string {
-	var uses []string
-
-	for u, s := range keyUsage {
-		if (ku & u) != 0 {
-			uses = append(uses, s)
-		}
-	}
-	sort.Strings(uses)
-
-	return strings.Join(uses, ", ")
-}
-
-func extUsage(ext []x509.ExtKeyUsage) string {
-	ns := make([]string, 0, len(ext))
-	for i := range ext {
-		ns = append(ns, extKeyUsages[ext[i]])
-	}
-	sort.Strings(ns)
-
-	return strings.Join(ns, ", ")
-}
-
-func showBasicConstraints(cert *x509.Certificate) {
-	fmt.Fprint(os.Stdout, "\tBasic constraints: ")
-	if cert.BasicConstraintsValid {
-		fmt.Fprint(os.Stdout, "valid")
-	} else {
-		fmt.Fprint(os.Stdout, "invalid")
-	}
-
-	if cert.IsCA {
-		fmt.Fprint(os.Stdout, ", is a CA certificate")
-		if !cert.BasicConstraintsValid {
-			fmt.Fprint(os.Stdout, " (basic constraint failure)")
-		}
-	} else {
-		fmt.Fprint(os.Stdout, "is not a CA certificate")
-		if cert.KeyUsage&x509.KeyUsageKeyEncipherment != 0 {
-			fmt.Fprint(os.Stdout, " (key encipherment usage enabled!)")
-		}
-	}
-
-	if (cert.MaxPathLen == 0 && cert.MaxPathLenZero) || (cert.MaxPathLen > 0) {
-		fmt.Fprintf(os.Stdout, ", max path length %d", cert.MaxPathLen)
-	}
-
-	fmt.Fprintln(os.Stdout)
-}
-
-const oneTrueDateFormat = "2006-01-02T15:04:05-0700"
-
-var (
+var config struct {
+	showHash   bool
 	dateFormat string
-	showHash   bool // if true, print a SHA256 hash of the certificate's Raw field
-)
-
-func wrapPrint(text string, indent int) {
-	tabs := ""
-	var tabsSb140 strings.Builder
-	for range indent {
-		tabsSb140.WriteString("\t")
-	}
-	tabs += tabsSb140.String()
-
-	fmt.Fprintf(os.Stdout, tabs+"%s\n", wrap(text, indent))
-}
-
-func displayCert(cert *x509.Certificate) {
-	fmt.Fprintln(os.Stdout, "CERTIFICATE")
-	if showHash {
-		fmt.Fprintln(os.Stdout, wrap(fmt.Sprintf("SHA256: %x", sha256.Sum256(cert.Raw)), 0))
-	}
-	fmt.Fprintln(os.Stdout, wrap("Subject: "+displayName(cert.Subject), 0))
-	fmt.Fprintln(os.Stdout, wrap("Issuer: "+displayName(cert.Issuer), 0))
-	fmt.Fprintf(os.Stdout, "\tSignature algorithm: %s / %s\n", sigAlgoPK(cert.SignatureAlgorithm),
-		sigAlgoHash(cert.SignatureAlgorithm))
-	fmt.Fprintln(os.Stdout, "Details:")
-	wrapPrint("Public key: "+certPublic(cert), 1)
-	fmt.Fprintf(os.Stdout, "\tSerial number: %s\n", cert.SerialNumber)
-
-	if len(cert.AuthorityKeyId) > 0 {
-		fmt.Fprintf(os.Stdout, "\t%s\n", wrap("AKI: "+dumpHex(cert.AuthorityKeyId), 1))
-	}
-	if len(cert.SubjectKeyId) > 0 {
-		fmt.Fprintf(os.Stdout, "\t%s\n", wrap("SKI: "+dumpHex(cert.SubjectKeyId), 1))
-	}
-
-	wrapPrint("Valid from: "+cert.NotBefore.Format(dateFormat), 1)
-	fmt.Fprintf(os.Stdout, "\t     until: %s\n", cert.NotAfter.Format(dateFormat))
-	fmt.Fprintf(os.Stdout, "\tKey usages: %s\n", keyUsages(cert.KeyUsage))
-
-	if len(cert.ExtKeyUsage) > 0 {
-		fmt.Fprintf(os.Stdout, "\tExtended usages: %s\n", extUsage(cert.ExtKeyUsage))
-	}
-
-	showBasicConstraints(cert)
-
-	validNames := make([]string, 0, len(cert.DNSNames)+len(cert.EmailAddresses)+len(cert.IPAddresses))
-	for i := range cert.DNSNames {
-		validNames = append(validNames, "dns:"+cert.DNSNames[i])
-	}
-
-	for i := range cert.EmailAddresses {
-		validNames = append(validNames, "email:"+cert.EmailAddresses[i])
-	}
-
-	for i := range cert.IPAddresses {
-		validNames = append(validNames, "ip:"+cert.IPAddresses[i].String())
-	}
-
-	sans := fmt.Sprintf("SANs (%d): %s\n", len(validNames), strings.Join(validNames, ", "))
-	wrapPrint(sans, 1)
-
-	l := len(cert.IssuingCertificateURL)
-	if l != 0 {
-		var aia string
-		if l == 1 {
-			aia = "AIA"
-		} else {
-			aia = "AIAs"
-		}
-		wrapPrint(fmt.Sprintf("%d %s:", l, aia), 1)
-		for _, url := range cert.IssuingCertificateURL {
-			wrapPrint(url, 2)
-		}
-	}
-
-	l = len(cert.OCSPServer)
-	if l > 0 {
-		title := "OCSP server"
-		if l > 1 {
-			title += "s"
-		}
-		wrapPrint(title+":\n", 1)
-		for _, ocspServer := range cert.OCSPServer {
-			wrapPrint(fmt.Sprintf("- %s\n", ocspServer), 2)
-		}
-	}
-}
-
-func displayAllCerts(in []byte, leafOnly bool) {
-	certs, err := certlib.ParseCertificatesPEM(in)
-	if err != nil {
-		certs, _, err = certlib.ParseCertificatesDER(in, "")
-		if err != nil {
-			_, _ = lib.Warn(err, "failed to parse certificates")
-			return
-		}
-	}
-
-	if len(certs) == 0 {
-		_, _ = lib.Warnx("no certificates found")
-		return
-	}
-
-	if leafOnly {
-		displayCert(certs[0])
-		return
-	}
-
-	for i := range certs {
-		displayCert(certs[i])
-	}
-}
-
-func displayAllCertsWeb(uri string, leafOnly bool) {
-	ci := getConnInfo(uri)
-	d := &tls.Dialer{Config: permissiveConfig()}
-	nc, err := d.DialContext(context.Background(), "tcp", ci.Addr)
-	if err != nil {
-		_, _ = lib.Warn(err, "couldn't connect to %s", ci.Addr)
-		return
-	}
-
-	conn, ok := nc.(*tls.Conn)
-	if !ok {
-		_, _ = lib.Warnx("invalid TLS connection (not a *tls.Conn)")
-		return
-	}
-	defer conn.Close()
-
-	state := conn.ConnectionState()
-	if err = conn.Close(); err != nil {
-		_, _ = lib.Warn(err, "couldn't close TLS connection")
-	}
-
-	d = &tls.Dialer{Config: verifyConfig(ci.Host)}
-	nc, err = d.DialContext(context.Background(), "tcp", ci.Addr)
-	if err == nil {
-		conn, ok = nc.(*tls.Conn)
-		if !ok {
-			_, _ = lib.Warnx("invalid TLS connection (not a *tls.Conn)")
-			return
-		}
-
-		err = conn.VerifyHostname(ci.Host)
-		if err == nil {
-			state = conn.ConnectionState()
-		}
-		conn.Close()
-	} else {
-		_, _ = lib.Warn(err, "TLS verification error with server name %s", ci.Host)
-	}
-
-	if len(state.PeerCertificates) == 0 {
-		_, _ = lib.Warnx("no certificates found")
-		return
-	}
-
-	if leafOnly {
-		displayCert(state.PeerCertificates[0])
-		return
-	}
-
-	if len(state.VerifiedChains) == 0 {
-		_, _ = lib.Warnx("no verified chains found; using peer chain")
-		for i := range state.PeerCertificates {
-			displayCert(state.PeerCertificates[i])
-		}
-	} else {
-		fmt.Fprintln(os.Stdout, "TLS chain verified successfully.")
-		for i := range state.VerifiedChains {
-			fmt.Fprintf(os.Stdout, "--- Verified certificate chain %d ---%s", i+1, "\n")
-			for j := range state.VerifiedChains[i] {
-				displayCert(state.VerifiedChains[i][j])
-			}
-		}
-	}
-}
-
-func shouldReadStdin(argc int, argv []string) bool {
-	if argc == 0 {
-		return true
-	}
-
-	if argc == 1 && argv[0] == "-" {
-		return true
-	}
-
-	return false
-}
-
-func readStdin(leafOnly bool) {
-	certs, err := io.ReadAll(os.Stdin)
-	if err != nil {
-		_, _ = lib.Warn(err, "couldn't read certificates from standard input")
-		os.Exit(1)
-	}
-
-	// This is needed for getting certs from JSON/jq.
-	certs = bytes.TrimSpace(certs)
-	certs = bytes.ReplaceAll(certs, []byte(`\n`), []byte{0xa})
-	certs = bytes.Trim(certs, `"`)
-	displayAllCerts(certs, leafOnly)
+	leafOnly   bool
 }
 
 func main() {
-	var leafOnly bool
-	flag.BoolVar(&showHash, "d", false, "show hashes of raw DER contents")
-	flag.StringVar(&dateFormat, "s", oneTrueDateFormat, "date `format` in Go time format")
-	flag.BoolVar(&leafOnly, "l", false, "only show the leaf certificate")
+	flag.BoolVar(&config.showHash, "d", false, "show hashes of raw DER contents")
+	flag.StringVar(&config.dateFormat, "s", lib.OneTrueDateFormat, "date `format` in Go time format")
+	flag.BoolVar(&config.leafOnly, "l", false, "only show the leaf certificate")
 	flag.Parse()
 
-	if shouldReadStdin(flag.NArg(), flag.Args()) {
-		readStdin(leafOnly)
-		return
-	}
+	tlsCfg := &tls.Config{InsecureSkipVerify: true} // #nosec G402 - tool intentionally inspects broken TLS
 
 	for _, filename := range flag.Args() {
 		fmt.Fprintf(os.Stdout, "--%s ---%s", filename, "\n")
-		if strings.HasPrefix(filename, "https://") {
-			displayAllCertsWeb(filename, leafOnly)
-		} else {
-			in, err := os.ReadFile(filename)
-			if err != nil {
-				_, _ = lib.Warn(err, "couldn't read certificate")
-				continue
-			}
+		certs, err := lib.GetCertificateChain(filename, tlsCfg)
+		if err != nil {
+			lib.Warn(err, "couldn't read certificate")
+			continue
+		}
 
-			displayAllCerts(in, leafOnly)
+		if config.leafOnly {
+			dump.DisplayCert(os.Stdout, certs[0])
+			continue
+		}
+
+		for i := range certs {
+			dump.DisplayCert(os.Stdout, certs[i])
 		}
 	}
 }

cmd/certdump/util.go

@@ -1,189 +0,0 @@
-package main
-
-import (
-	"crypto/tls"
-	"crypto/x509"
-	"fmt"
-	"net"
-	"strings"
-
-	"github.com/kr/text"
-)
-
-// following two lifted from CFSSL, (replace-regexp "\(.+\): \(.+\),"
-// "\2: \1,")
-
-const (
-	sSHA256 = "SHA256"
-	sSHA512 = "SHA512"
-)
-
-var keyUsage = map[x509.KeyUsage]string{
-	x509.KeyUsageDigitalSignature:  "digital signature",
-	x509.KeyUsageContentCommitment: "content committment",
-	x509.KeyUsageKeyEncipherment:   "key encipherment",
-	x509.KeyUsageKeyAgreement:      "key agreement",
-	x509.KeyUsageDataEncipherment:  "data encipherment",
-	x509.KeyUsageCertSign:          "cert sign",
-	x509.KeyUsageCRLSign:           "crl sign",
-	x509.KeyUsageEncipherOnly:      "encipher only",
-	x509.KeyUsageDecipherOnly:      "decipher only",
-}
-
-var extKeyUsages = map[x509.ExtKeyUsage]string{
-	x509.ExtKeyUsageAny:                            "any",
-	x509.ExtKeyUsageServerAuth:                     "server auth",
-	x509.ExtKeyUsageClientAuth:                     "client auth",
-	x509.ExtKeyUsageCodeSigning:                    "code signing",
-	x509.ExtKeyUsageEmailProtection:                "s/mime",
-	x509.ExtKeyUsageIPSECEndSystem:                 "ipsec end system",
-	x509.ExtKeyUsageIPSECTunnel:                    "ipsec tunnel",
-	x509.ExtKeyUsageIPSECUser:                      "ipsec user",
-	x509.ExtKeyUsageTimeStamping:                   "timestamping",
-	x509.ExtKeyUsageOCSPSigning:                    "ocsp signing",
-	x509.ExtKeyUsageMicrosoftServerGatedCrypto:     "microsoft sgc",
-	x509.ExtKeyUsageNetscapeServerGatedCrypto:      "netscape sgc",
-	x509.ExtKeyUsageMicrosoftCommercialCodeSigning: "microsoft commercial code signing",
-	x509.ExtKeyUsageMicrosoftKernelCodeSigning:     "microsoft kernel code signing",
-}
-
-func sigAlgoPK(a x509.SignatureAlgorithm) string {
-	switch a {
-	case x509.MD2WithRSA, x509.MD5WithRSA, x509.SHA1WithRSA, x509.SHA256WithRSA, x509.SHA384WithRSA, x509.SHA512WithRSA:
-		return "RSA"
-	case x509.SHA256WithRSAPSS, x509.SHA384WithRSAPSS, x509.SHA512WithRSAPSS:
-		return "RSA-PSS"
-	case x509.ECDSAWithSHA1, x509.ECDSAWithSHA256, x509.ECDSAWithSHA384, x509.ECDSAWithSHA512:
-		return "ECDSA"
-	case x509.DSAWithSHA1, x509.DSAWithSHA256:
-		return "DSA"
-	case x509.PureEd25519:
-		return "Ed25519"
-	case x509.UnknownSignatureAlgorithm:
-		return "unknown public key algorithm"
-	default:
-		return "unknown public key algorithm"
-	}
-}
-
-func sigAlgoHash(a x509.SignatureAlgorithm) string {
-	switch a {
-	case x509.MD2WithRSA:
-		return "MD2"
-	case x509.MD5WithRSA:
-		return "MD5"
-	case x509.SHA1WithRSA, x509.ECDSAWithSHA1, x509.DSAWithSHA1:
-		return "SHA1"
-	case x509.SHA256WithRSA, x509.ECDSAWithSHA256, x509.DSAWithSHA256:
-		return sSHA256
-	case x509.SHA256WithRSAPSS:
-		return sSHA256
-	case x509.SHA384WithRSA, x509.ECDSAWithSHA384:
-		return "SHA384"
-	case x509.SHA384WithRSAPSS:
-		return "SHA384"
-	case x509.SHA512WithRSA, x509.ECDSAWithSHA512:
-		return sSHA512
-	case x509.SHA512WithRSAPSS:
-		return sSHA512
-	case x509.PureEd25519:
-		return sSHA512
-	case x509.UnknownSignatureAlgorithm:
-		return "unknown hash algorithm"
-	default:
-		return "unknown hash algorithm"
-	}
-}
-
-const maxLine = 78
-
-func makeIndent(n int) string {
-	s := "    "
-	var sSb97 strings.Builder
-	for range n {
-		sSb97.WriteString("        ")
-	}
-	s += sSb97.String()
-	return s
-}
-
-func indentLen(n int) int {
-	return 4 + (8 * n)
-}
-
-// this isn't real efficient, but that's not a problem here.
-func wrap(s string, indent int) string {
-	if indent > 3 {
-		indent = 3
-	}
-
-	wrapped := text.Wrap(s, maxLine)
-	lines := strings.SplitN(wrapped, "\n", 2)
-	if len(lines) == 1 {
-		return lines[0]
-	}
-
-	if (maxLine - indentLen(indent)) <= 0 {
-		panic("too much indentation")
-	}
-
-	rest := strings.Join(lines[1:], " ")
-	wrapped = text.Wrap(rest, maxLine-indentLen(indent))
-	return lines[0] + "\n" + text.Indent(wrapped, makeIndent(indent))
-}
-
-func dumpHex(in []byte) string {
-	var s string
-	var sSb130 strings.Builder
-	for i := range in {
-		sSb130.WriteString(fmt.Sprintf("%02X:", in[i]))
-	}
-	s += sSb130.String()
-
-	return strings.Trim(s, ":")
-}
-
-// permissiveConfig returns a maximally-accepting TLS configuration;
-// the purpose is to look at the cert, not verify the security properties
-// of the connection.
-func permissiveConfig() *tls.Config {
-	return &tls.Config{
-		InsecureSkipVerify: true,
-	} // #nosec G402
-}
-
-// verifyConfig returns a config that will verify the connection.
-func verifyConfig(hostname string) *tls.Config {
-	return &tls.Config{
-		ServerName: hostname,
-	} // #nosec G402
-}
-
-type connInfo struct {
-	// The original URI provided.
-	URI string
-
-	// The hostname of the server.
-	Host string
-
-	// The port to connect on.
-	Port string
-
-	// The address to connect to.
-	Addr string
-}
-
-func getConnInfo(uri string) *connInfo {
-	ci := &connInfo{URI: uri}
-	ci.Host = uri[len("https://"):]
-
-	host, port, err := net.SplitHostPort(ci.Host)
-	if err != nil {
-		ci.Port = "443"
-	} else {
-		ci.Host = host
-		ci.Port = port
-	}
-	ci.Addr = net.JoinHostPort(ci.Host, ci.Port)
-	return ci
-}

cmd/certexpiry/main.go

@@ -2,98 +2,52 @@ package main
 
 import (
 	"crypto/x509"
-	"crypto/x509/pkix"
 	"flag"
 	"fmt"
-	"os"
-	"strings"
-	"time"
 
-	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/verify"
 	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-var warnOnly bool
-var leeway = 2160 * time.Hour // three months
-
-func displayName(name pkix.Name) string {
-	var ns []string
-
-	if name.CommonName != "" {
-		ns = append(ns, name.CommonName)
-	}
-
-	for i := range name.Country {
-		ns = append(ns, fmt.Sprintf("C=%s", name.Country[i]))
-	}
-
-	for i := range name.Organization {
-		ns = append(ns, fmt.Sprintf("O=%s", name.Organization[i]))
-	}
-
-	for i := range name.OrganizationalUnit {
-		ns = append(ns, fmt.Sprintf("OU=%s", name.OrganizationalUnit[i]))
-	}
-
-	for i := range name.Locality {
-		ns = append(ns, fmt.Sprintf("L=%s", name.Locality[i]))
-	}
-
-	for i := range name.Province {
-		ns = append(ns, fmt.Sprintf("ST=%s", name.Province[i]))
-	}
-
-	if len(ns) > 0 {
-		return "/" + strings.Join(ns, "/")
-	}
-
-	die.With("no subject information in root")
-	return ""
-}
-
-func expires(cert *x509.Certificate) time.Duration {
-	return time.Until(cert.NotAfter)
-}
-
-func inDanger(cert *x509.Certificate) bool {
-	return expires(cert) < leeway
-}
-
-func checkCert(cert *x509.Certificate) {
-	warn := inDanger(cert)
-	name := displayName(cert.Subject)
-	name = fmt.Sprintf("%s/SN=%s", name, cert.SerialNumber)
-	expiry := expires(cert)
-	if warnOnly {
-		if warn {
-			fmt.Fprintf(os.Stderr, "%s expires on %s (in %s)\n", name, cert.NotAfter, expiry)
-		}
-	} else {
-		fmt.Printf("%s expires on %s (in %s)\n", name, cert.NotAfter, expiry)
-	}
-}
-
 func main() {
+	var (
+		skipVerify bool
+		strictTLS  bool
+		leeway     = verify.DefaultLeeway
+		warnOnly   bool
+	)
+
+	lib.StrictTLSFlag(&strictTLS)
+
+	flag.BoolVar(&skipVerify, "k", false, "skip server verification") // #nosec G402
 	flag.BoolVar(&warnOnly, "q", false, "only warn about expiring certs")
 	flag.DurationVar(&leeway, "t", leeway, "warn if certificates are closer than this to expiring")
 	flag.Parse()
 
-	for _, file := range flag.Args() {
-		in, err := os.ReadFile(file)
-		if err != nil {
-			_, _ = lib.Warn(err, "failed to read file")
-			continue
-		}
+	tlsCfg, err := lib.BaselineTLSConfig(skipVerify, strictTLS)
+	die.If(err)
 
-		certs, err := certlib.ParseCertificatesPEM(in)
+	for _, file := range flag.Args() {
+		var certs []*x509.Certificate
+
+		certs, err = lib.GetCertificateChain(file, tlsCfg)
 		if err != nil {
 			_, _ = lib.Warn(err, "while parsing certificates")
 			continue
 		}
 
 		for _, cert := range certs {
-			checkCert(cert)
+			check := verify.NewCertCheck(cert, leeway)
+
+			if warnOnly {
+				if err = check.Err(); err != nil {
+					lib.Warn(err, "certificate is expiring")
+				}
+			} else {
+				fmt.Printf("%s expires on %s (in %s)\n", check.Name(),
+					cert.NotAfter, check.Expiry())
+			}
 		}
 	}
 }

cmd/certser/main.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"crypto/x509"
+	"flag"
+	"fmt"
+	"strings"
+
+	"git.wntrmute.dev/kyle/goutils/die"
+	"git.wntrmute.dev/kyle/goutils/lib"
+)
+
+const displayInt lib.HexEncodeMode = iota
+
+func parseDisplayMode(mode string) lib.HexEncodeMode {
+	mode = strings.ToLower(mode)
+
+	if mode == "int" {
+		return displayInt
+	}
+
+	return lib.ParseHexEncodeMode(mode)
+}
+
+func serialString(cert *x509.Certificate, mode lib.HexEncodeMode) string {
+	if mode == displayInt {
+		return cert.SerialNumber.String()
+	}
+
+	return lib.HexEncode(cert.SerialNumber.Bytes(), mode)
+}
+
+func main() {
+	var skipVerify bool
+	var strictTLS bool
+	lib.StrictTLSFlag(&strictTLS)
+	displayAs := flag.String("d", "int", "display mode (int, hex, uhex)")
+	showExpiry := flag.Bool("e", false, "show expiry date")
+	flag.BoolVar(&skipVerify, "k", false, "skip server verification") // #nosec G402
+	flag.Parse()
+
+	tlsCfg, err := lib.BaselineTLSConfig(skipVerify, strictTLS)
+	die.If(err)
+
+	displayMode := parseDisplayMode(*displayAs)
+
+	for _, arg := range flag.Args() {
+		var cert *x509.Certificate
+
+		cert, err = lib.GetCertificate(arg, tlsCfg)
+		die.If(err)
+
+		fmt.Printf("%s: %s", arg, serialString(cert, displayMode))
+		if *showExpiry {
+			fmt.Printf(" (%s)", cert.NotAfter.Format("2006-01-02"))
+		}
+		fmt.Println()
+	}
+}

cmd/certverify/main.go

@@ -5,33 +5,18 @@ import (
 	"flag"
 	"fmt"
 	"os"
-	"time"
 
 	"git.wntrmute.dev/kyle/goutils/certlib"
-	"git.wntrmute.dev/kyle/goutils/certlib/revoke"
+	"git.wntrmute.dev/kyle/goutils/certlib/verify"
+	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-func printRevocation(cert *x509.Certificate) {
-	remaining := time.Until(cert.NotAfter)
-	fmt.Printf("certificate expires in %s.\n", lib.Duration(remaining))
-
-	revoked, ok := revoke.VerifyCertificate(cert)
-	if !ok {
-		fmt.Fprintf(os.Stderr, "[!] the revocation check failed (failed to determine whether certificate\nwas revoked)")
-		return
-	}
-
-	if revoked {
-		fmt.Fprintf(os.Stderr, "[!] the certificate has been revoked\n")
-		return
-	}
-}
-
 type appConfig struct {
-	caFile, intFile         string
-	forceIntermediateBundle bool
-	revexp, verbose         bool
+	caFile, intFile             string
+	forceIntermediateBundle     bool
+	revexp, skipVerify, verbose bool
+	strictTLS                   bool
 }
 
 func parseFlags() appConfig {
@@ -40,104 +25,69 @@ func parseFlags() appConfig {
 	flag.StringVar(&cfg.intFile, "i", "", "intermediate `bundle`")
 	flag.BoolVar(&cfg.forceIntermediateBundle, "f", false,
 		"force the use of the intermediate bundle, ignoring any intermediates bundled with certificate")
+	flag.BoolVar(&cfg.skipVerify, "k", false, "skip CA verification")
 	flag.BoolVar(&cfg.revexp, "r", false, "print revocation and expiry information")
 	flag.BoolVar(&cfg.verbose, "v", false, "verbose")
+	lib.StrictTLSFlag(&cfg.strictTLS)
 	flag.Parse()
+
+	if flag.NArg() == 0 {
+		die.With("usage: certverify targets...")
+	}
+
 	return cfg
 }
 
-func loadRoots(caFile string, verbose bool) (*x509.CertPool, error) {
-	if caFile == "" {
-		return x509.SystemCertPool()
-	}
-
-	if verbose {
-		fmt.Println("[+] loading root certificates from", caFile)
-	}
-	return certlib.LoadPEMCertPool(caFile)
-}
-
-func loadIntermediates(intFile string, verbose bool) (*x509.CertPool, error) {
-	if intFile == "" {
-		return x509.NewCertPool(), nil
-	}
-	if verbose {
-		fmt.Println("[+] loading intermediate certificates from", intFile)
-	}
-	// Note: use intFile here (previously used caFile mistakenly)
-	return certlib.LoadPEMCertPool(intFile)
-}
-
-func addBundledIntermediates(chain []*x509.Certificate, pool *x509.CertPool, verbose bool) {
-	for _, intermediate := range chain[1:] {
-		if verbose {
-			fmt.Printf("[+] adding intermediate with SKI %x\n", intermediate.SubjectKeyId)
-		}
-		pool.AddCert(intermediate)
-	}
-}
-
-func verifyCert(cert *x509.Certificate, roots, ints *x509.CertPool) error {
-	opts := x509.VerifyOptions{
-		Intermediates: ints,
-		Roots:         roots,
-		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
-	}
-	_, err := cert.Verify(opts)
-	return err
-}
-
-func run(cfg appConfig) error {
-	roots, err := loadRoots(cfg.caFile, cfg.verbose)
-	if err != nil {
-		return err
-	}
-
-	ints, err := loadIntermediates(cfg.intFile, cfg.verbose)
-	if err != nil {
-		return err
-	}
-
-	if flag.NArg() != 1 {
-		fmt.Fprintf(os.Stderr, "Usage: %s [-ca bundle] [-i bundle] cert", lib.ProgName())
-	}
-
-	fileData, err := os.ReadFile(flag.Arg(0))
-	if err != nil {
-		return err
-	}
-
-	chain, err := certlib.ParseCertificatesPEM(fileData)
-	if err != nil {
-		return err
-	}
-	if cfg.verbose {
-		fmt.Printf("[+] %s has %d certificates\n", flag.Arg(0), len(chain))
-	}
-
-	cert := chain[0]
-	if len(chain) > 1 && !cfg.forceIntermediateBundle {
-		addBundledIntermediates(chain, ints, cfg.verbose)
-	}
-
-	if err = verifyCert(cert, roots, ints); err != nil {
-		return fmt.Errorf("certificate verification failed: %w", err)
-	}
-
-	if cfg.verbose {
-		fmt.Println("OK")
-	}
-
-	if cfg.revexp {
-		printRevocation(cert)
-	}
-	return nil
-}
-
 func main() {
+	var (
+		roots, ints *x509.CertPool
+		err         error
+		failed      bool
+	)
+
 	cfg := parseFlags()
-	if err := run(cfg); err != nil {
-		fmt.Fprintf(os.Stderr, "%v\n", err)
+
+	opts := &verify.Opts{
+		CheckRevocation:    cfg.revexp,
+		ForceIntermediates: cfg.forceIntermediateBundle,
+		Verbose:            cfg.verbose,
+	}
+
+	if cfg.caFile != "" {
+		if cfg.verbose {
+			fmt.Printf("loading CA certificates from %s\n", cfg.caFile)
+		}
+
+		roots, err = certlib.LoadPEMCertPool(cfg.caFile)
+		die.If(err)
+	}
+
+	if cfg.intFile != "" {
+		if cfg.verbose {
+			fmt.Printf("loading intermediate certificates from %s\n", cfg.intFile)
+		}
+
+		ints, err = certlib.LoadPEMCertPool(cfg.intFile)
+		die.If(err)
+	}
+
+	opts.Config, err = lib.BaselineTLSConfig(cfg.skipVerify, cfg.strictTLS)
+	die.If(err)
+
+	opts.Config.RootCAs = roots
+	opts.Intermediates = ints
+
+	for _, arg := range flag.Args() {
+		_, err = verify.Chain(os.Stdout, arg, opts)
+		if err != nil {
+			lib.Warn(err, "while verifying %s", arg)
+			failed = true
+		} else {
+			fmt.Printf("%s: OK\n", arg)
+		}
+	}
+
+	if failed {
 		os.Exit(1)
 	}
 }

cmd/csrpubdump/main.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"os"
 
+	"git.wntrmute.dev/kyle/goutils/certlib"
 	"git.wntrmute.dev/kyle/goutils/die"
 )
 
@@ -19,14 +20,7 @@ func main() {
 		in, err := os.ReadFile(fileName)
 		die.If(err)
 
-		if p, _ := pem.Decode(in); p != nil {
-			if p.Type != "CERTIFICATE REQUEST" {
-				die.With("INVALID FILE TYPE")
-			}
-			in = p.Bytes
-		}
-
-		csr, err := x509.ParseCertificateRequest(in)
+		csr, _, err := certlib.ParseCSR(in)
 		die.If(err)
 
 		out, err := x509.MarshalPKIXPublicKey(csr.PublicKey)

cmd/kgz/README

@@ -3,18 +3,31 @@ kgz
 kgz is like gzip, but supports compressing and decompressing to a different
 directory than the source file is in.
 
-Usage: kgz [-l] source [target]
+Usage: kgz [-l] [-k] [-m] [-x] [--uid N] [--gid N] source [target]
 
-If target is a directory, the basename of the sourcefile will be used
+If target is a directory, the basename of the source file will be used
 as the target filename. Compression and decompression is selected
 based on whether the source filename ends in ".gz".
 
 Flags:
-	-l level	Compression level (0-9). Only meaninful when
-			    compressing a file.
+	-l level    Compression level (0-9). Only meaningful when compressing.
     -u          Do not restrict the size during decompression. As
                 a safeguard against gzip bombs, the maximum size
                 allowed is 32 * the compressed file size.
+    -k          Keep the source file (do not remove it after successful
+                compression or decompression).
+    -m          On decompression, set the file mtime from the gzip header.
+    -x          On compression, include uid/gid/mode/ctime in the gzip Extra
+                field so that decompression can restore them. The Extra payload
+                is an ASN.1 DER-encoded struct.
+    --uid N     When used with -x, set UID in Extra to N (override source).
+    --gid N     When used with -x, set GID in Extra to N (override source).
+
+Metadata notes:
+- mtime is stored in the standard gzip header and restored with -m.
+- uid/gid/mode/ctime are stored in a kgz-specific Extra subfield as an ASN.1
+  DER-encoded struct. Restoring
+  uid/gid may fail without sufficient privileges; such errors are ignored.
 
 
 

cmd/kgz/main.go

@@ -3,23 +3,178 @@ package main
 import (
 	"compress/flate"
 	"compress/gzip"
+	"encoding/asn1"
+	"encoding/binary"
 	"flag"
 	"fmt"
 	"io"
+	"math"
 	"os"
 	"path/filepath"
 	"strings"
+
+	"golang.org/x/sys/unix"
+
+	goutilslib "git.wntrmute.dev/kyle/goutils/lib"
 )
 
 const gzipExt = ".gz"
 
-func compress(path, target string, level int) error {
+// kgzExtraID is the two-byte subfield identifier used in the gzip Extra field
+// for kgz-specific metadata.
+var kgzExtraID = [2]byte{'K', 'G'}
+
+// buildKGExtra constructs the gzip Extra subfield payload for kgz metadata.
+//
+// The payload is an ASN.1 DER-encoded struct with the following fields:
+//
+//	Version    INTEGER (currently 1)
+//	UID        INTEGER
+//	GID        INTEGER
+//	Mode       INTEGER (permission bits)
+//	CTimeSec   INTEGER (seconds)
+//	CTimeNSec  INTEGER (nanoseconds)
+//
+// The ASN.1 blob is wrapped in a gzip Extra subfield with ID 'K','G'.
+func buildKGExtra(uid, gid, mode uint32, ctimeS int64, ctimeNs int32) []byte {
+	// Define the ASN.1 structure to encode
+	type KGZExtra struct {
+		Version   int
+		UID       int
+		GID       int
+		Mode      int
+		CTimeSec  int64
+		CTimeNSec int32
+	}
+
+	payload, err := asn1.Marshal(KGZExtra{
+		Version:   1,
+		UID:       int(uid),
+		GID:       int(gid),
+		Mode:      int(mode),
+		CTimeSec:  ctimeS,
+		CTimeNSec: ctimeNs,
+	})
+	if err != nil {
+		// On marshal failure, return empty to avoid breaking compression
+		return nil
+	}
+
+	// Wrap in gzip subfield: [ID1 ID2 LEN(lo) LEN(hi) PAYLOAD]
+	// Guard against payload length overflow to uint16 for the extra subfield length.
+	if len(payload) > int(math.MaxUint16) {
+		return nil
+	}
+	extra := make([]byte, 4+len(payload))
+	extra[0] = kgzExtraID[0]
+	extra[1] = kgzExtraID[1]
+	binary.LittleEndian.PutUint16(extra[2:], uint16(len(payload)&0xFFFF)) //#nosec G115 - masked
+	copy(extra[4:], payload)
+	return extra
+}
+
+// clampToInt32 clamps an int value into the int32 range using a switch to
+// satisfy linters that prefer switch over if-else chains for ordered checks.
+func clampToInt32(v int) int32 {
+	switch {
+	case v > int(math.MaxInt32):
+		return math.MaxInt32
+	case v < int(math.MinInt32):
+		return math.MinInt32
+	default:
+		return int32(v)
+	}
+}
+
+// buildExtraForPath prepares the gzip Extra field for kgz by collecting
+// uid/gid/mode and ctime information, applying any overrides, and encoding it.
+func buildExtraForPath(st unix.Stat_t, path string, setUID, setGID int) []byte {
+	uid := st.Uid
+	gid := st.Gid
+	if setUID >= 0 {
+		if uint64(setUID) <= math.MaxUint32 {
+			uid = uint32(setUID & 0xFFFFFFFF) //#nosec G115 - masked
+		}
+	}
+	if setGID >= 0 {
+		if uint64(setGID) <= math.MaxUint32 {
+			gid = uint32(setGID & 0xFFFFFFFF) //#nosec G115 - masked
+		}
+	}
+	mode := uint32(st.Mode & 0o7777)
+
+	// Use portable helper to gather ctime
+	var cts int64
+	var ctns int32
+	if ft, err := goutilslib.LoadFileTime(path); err == nil {
+		cts = ft.Changed.Unix()
+		ctns = clampToInt32(ft.Changed.Nanosecond())
+	}
+
+	return buildKGExtra(uid, gid, mode, cts, ctns)
+}
+
+// parseKGExtra scans a gzip Extra blob and returns kgz metadata if present.
+func parseKGExtra(extra []byte) (uint32, uint32, uint32, int64, int32, bool) {
+	i := 0
+	for i+4 <= len(extra) {
+		id1 := extra[i]
+		id2 := extra[i+1]
+		l := int(binary.LittleEndian.Uint16(extra[i+2 : i+4]))
+		i += 4
+		if i+l > len(extra) {
+			break
+		}
+		if id1 == kgzExtraID[0] && id2 == kgzExtraID[1] {
+			// ASN.1 decode payload
+			payload := extra[i : i+l]
+			var s struct {
+				Version   int
+				UID       int
+				GID       int
+				Mode      int
+				CTimeSec  int64
+				CTimeNSec int32
+			}
+			if _, err := asn1.Unmarshal(payload, &s); err != nil {
+				return 0, 0, 0, 0, 0, false
+			}
+			if s.Version != 1 {
+				return 0, 0, 0, 0, 0, false
+			}
+			// Validate ranges before converting from int -> uint32 to avoid overflow.
+			if s.UID < 0 || s.GID < 0 || s.Mode < 0 {
+				return 0, 0, 0, 0, 0, false
+			}
+			if uint64(s.UID) > math.MaxUint32 || uint64(s.GID) > math.MaxUint32 || uint64(s.Mode) > math.MaxUint32 {
+				return 0, 0, 0, 0, 0, false
+			}
+
+			return uint32(s.UID & 0xFFFFFFFF), uint32(s.GID & 0xFFFFFFFF),
+				uint32(s.Mode & 0xFFFFFFFF), s.CTimeSec, s.CTimeNSec, true //#nosec G115 - masked
+		}
+		i += l
+	}
+	return 0, 0, 0, 0, 0, false
+}
+
+func compress(path, target string, level int, includeExtra bool, setUID, setGID int) error {
 	sourceFile, err := os.Open(path)
 	if err != nil {
 		return fmt.Errorf("opening file for read: %w", err)
 	}
 	defer sourceFile.Close()
 
+	// Gather file metadata
+	var st unix.Stat_t
+	if err = unix.Stat(path, &st); err != nil {
+		return fmt.Errorf("stat source: %w", err)
+	}
+	fi, err := sourceFile.Stat()
+	if err != nil {
+		return fmt.Errorf("stat source file: %w", err)
+	}
+
 	destFile, err := os.Create(target)
 	if err != nil {
 		return fmt.Errorf("opening file for write: %w", err)
@@ -30,6 +185,11 @@ func compress(path, target string, level int) error {
 	if err != nil {
 		return fmt.Errorf("invalid compression level: %w", err)
 	}
+	// Set header metadata
+	gzipCompressor.ModTime = fi.ModTime()
+	if includeExtra {
+		gzipCompressor.Extra = buildExtraForPath(st, path, setUID, setGID)
+	}
 	defer gzipCompressor.Close()
 
 	_, err = io.Copy(gzipCompressor, sourceFile)
@@ -40,7 +200,7 @@ func compress(path, target string, level int) error {
 	return nil
 }
 
-func uncompress(path, target string, unrestrict bool) error {
+func uncompress(path, target string, unrestrict bool, preserveMtime bool) error {
 	sourceFile, err := os.Open(path)
 	if err != nil {
 		return fmt.Errorf("opening file for read: %w", err)
@@ -79,19 +239,40 @@ func uncompress(path, target string, unrestrict bool) error {
 	if err != nil {
 		return fmt.Errorf("uncompressing file: %w", err)
 	}
-
+	// Apply metadata from Extra (uid/gid/mode) if present
+	if gzipUncompressor.Header.Extra != nil {
+		if uid, gid, mode, _, _, ok := parseKGExtra(gzipUncompressor.Header.Extra); ok {
+			// Chmod
+			_ = os.Chmod(target, os.FileMode(mode))
+			// Chown (may fail without privileges)
+			_ = os.Chown(target, int(uid), int(gid))
+		}
+	}
+	// Preserve mtime if requested
+	if preserveMtime {
+		mt := gzipUncompressor.Header.ModTime
+		if !mt.IsZero() {
+			// Set both atime and mtime to mt for simplicity
+			_ = os.Chtimes(target, mt, mt)
+		}
+	}
 	return nil
 }
 
 func usage(w io.Writer) {
-	fmt.Fprintf(w, `Usage: %s [-l] source [target]
+	fmt.Fprintf(w, `Usage: %s [-l] [-k] [-m] [-x] [--uid N] [--gid N] source [target]
 
 kgz is like gzip, but supports compressing and decompressing to a different
 directory than the source file is in.
 
 Flags:
-	-l level	Compression level (0-9). Only meaninful when
-			compressing a file.
+    -l level    Compression level (0-9). Only meaningful when compressing.
+    -u          Do not restrict the size during decompression (gzip bomb guard is 32x).
+    -k          Keep the source file (do not remove it after successful (de)compression).
+    -m          On decompression, set the file mtime from the gzip header.
+    -x          On compression, include uid/gid/mode/ctime in the gzip Extra field.
+    --uid N     When used with -x, set UID in Extra to N (overrides source owner).
+    --gid N     When used with -x, set GID in Extra to N (overrides source group).
 `, os.Args[0])
 }
 
@@ -150,9 +331,19 @@ func main() {
 	var target = "."
 	var err error
 	var unrestrict bool
+	var keep bool
+	var preserveMtime bool
+	var includeExtra bool
+	var setUID int
+	var setGID int
 
 	flag.IntVar(&level, "l", flate.DefaultCompression, "compression level")
 	flag.BoolVar(&unrestrict, "u", false, "do not restrict decompression")
+	flag.BoolVar(&keep, "k", false, "keep the source file (do not remove it)")
+	flag.BoolVar(&preserveMtime, "m", false, "on decompression, set mtime from gzip header")
+	flag.BoolVar(&includeExtra, "x", false, "on compression, include uid/gid/mode/ctime in gzip Extra")
+	flag.IntVar(&setUID, "uid", -1, "when used with -x, set UID in Extra to this value")
+	flag.IntVar(&setGID, "gid", -1, "when used with -x, set GID in Extra to this value")
 	flag.Parse()
 
 	if flag.NArg() < 1 || flag.NArg() > 2 {
@@ -172,12 +363,15 @@ func main() {
 			os.Exit(1)
 		}
 
-		err = uncompress(path, target, unrestrict)
+		err = uncompress(path, target, unrestrict, preserveMtime)
 		if err != nil {
 			os.Remove(target)
 			fmt.Fprintf(os.Stderr, "%s\n", err)
 			os.Exit(1)
 		}
+		if !keep {
+			_ = os.Remove(path)
+		}
 		return
 	}
 
@@ -187,10 +381,13 @@ func main() {
 		os.Exit(1)
 	}
 
-	err = compress(path, target, level)
+	err = compress(path, target, level, includeExtra, setUID, setGID)
 	if err != nil {
 		os.Remove(target)
 		fmt.Fprintf(os.Stderr, "%s\n", err)
 		os.Exit(1)
 	}
+	if !keep {
+		_ = os.Remove(path)
+	}
 }

cmd/rhash/main.go

@@ -9,6 +9,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
+	"time"
 
 	"git.wntrmute.dev/kyle/goutils/ahash"
 	"git.wntrmute.dev/kyle/goutils/die"
@@ -82,8 +83,13 @@ func main() {
 			_, _ = lib.Warn(reqErr, "building request for %s", remote)
 			continue
 		}
-		client := &http.Client{}
-		resp, err := client.Do(req)
+		// Use proxy-aware HTTP client with a reasonable timeout for connects/handshakes
+		httpClient, err := lib.NewHTTPClient(lib.DialerOpts{Timeout: 30 * time.Second})
+		if err != nil {
+			_, _ = lib.Warn(err, "building HTTP client for %s", remote)
+			continue
+		}
+		resp, err := httpClient.Do(req)
 		if err != nil {
 			_, _ = lib.Warn(err, "fetching %s", remote)
 			continue

cmd/ski/main.go

@@ -1,30 +1,19 @@
 package main
 
 import (
-	"bytes"
-	"crypto"
-	"crypto/ecdsa"
-	"crypto/rsa"
-	"crypto/sha1" // #nosec G505
-	"crypto/x509"
-	"crypto/x509/pkix"
-	"encoding/asn1"
-	"encoding/pem"
+
+	// #nosec G505
+
 	"flag"
 	"fmt"
 	"io"
 	"os"
-	"strings"
 
+	"git.wntrmute.dev/kyle/goutils/certlib/ski"
 	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-const (
-	keyTypeRSA   = "RSA"
-	keyTypeECDSA = "ECDSA"
-)
-
 func usage(w io.Writer) {
 	fmt.Fprintf(w, `ski: print subject key info for PEM-encoded files
 
@@ -32,10 +21,10 @@ Usage:
 	ski [-hm] files...
 
 Flags:
+	-d  Hex encoding mode.
 	-h	Print this help message.
 	-m	All SKIs should match; as soon as an SKI mismatch is found,
 		it is reported.
-
 `)
 }
 
@@ -43,164 +32,37 @@ func init() {
 	flag.Usage = func() { usage(os.Stderr) }
 }
 
-func parse(path string) ([]byte, string, string) {
-	data, err := os.ReadFile(path)
-	die.If(err)
-
-	data = bytes.TrimSpace(data)
-	p, rest := pem.Decode(data)
-	if len(rest) > 0 {
-		_, _ = lib.Warnx("trailing data in PEM file")
-	}
-
-	if p == nil {
-		die.With("no PEM data found")
-	}
-
-	data = p.Bytes
-
-	var (
-		public []byte
-		kt     string
-		ft     string
-	)
-
-	switch p.Type {
-	case "PRIVATE KEY", "RSA PRIVATE KEY", "EC PRIVATE KEY":
-		public, kt = parseKey(data)
-		ft = "private key"
-	case "CERTIFICATE":
-		public, kt = parseCertificate(data)
-		ft = "certificate"
-	case "CERTIFICATE REQUEST":
-		public, kt = parseCSR(data)
-		ft = "certificate request"
-	default:
-		die.With("unknown PEM type %s", p.Type)
-	}
-
-	return public, kt, ft
-}
-
-func parseKey(data []byte) ([]byte, string) {
-	privInterface, err := x509.ParsePKCS8PrivateKey(data)
-	if err != nil {
-		privInterface, err = x509.ParsePKCS1PrivateKey(data)
-		if err != nil {
-			privInterface, err = x509.ParseECPrivateKey(data)
-			if err != nil {
-				die.With("couldn't parse private key.")
-			}
-		}
-	}
-
-	var priv crypto.Signer
-	var kt string
-	switch p := privInterface.(type) {
-	case *rsa.PrivateKey:
-		priv = p
-		kt = keyTypeRSA
-	case *ecdsa.PrivateKey:
-		priv = p
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown private key type %T", privInterface)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(priv.Public())
-	die.If(err)
-
-	return public, kt
-}
-
-func parseCertificate(data []byte) ([]byte, string) {
-	cert, err := x509.ParseCertificate(data)
-	die.If(err)
-
-	pub := cert.PublicKey
-	var kt string
-	switch pub.(type) {
-	case *rsa.PublicKey:
-		kt = keyTypeRSA
-	case *ecdsa.PublicKey:
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown public key type %T", pub)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(pub)
-	die.If(err)
-	return public, kt
-}
-
-func parseCSR(data []byte) ([]byte, string) {
-	csr, err := x509.ParseCertificateRequest(data)
-	die.If(err)
-
-	pub := csr.PublicKey
-	var kt string
-	switch pub.(type) {
-	case *rsa.PublicKey:
-		kt = keyTypeRSA
-	case *ecdsa.PublicKey:
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown public key type %T", pub)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(pub)
-	die.If(err)
-	return public, kt
-}
-
-func dumpHex(in []byte) string {
-	var s string
-	var sSb153 strings.Builder
-	for i := range in {
-		sSb153.WriteString(fmt.Sprintf("%02X:", in[i]))
-	}
-	s += sSb153.String()
-
-	return strings.Trim(s, ":")
-}
-
-type subjectPublicKeyInfo struct {
-	Algorithm        pkix.AlgorithmIdentifier
-	SubjectPublicKey asn1.BitString
-}
-
 func main() {
 	var help, shouldMatch bool
+	var displayModeString string
+	flag.StringVar(&displayModeString, "d", "lower", "hex encoding mode")
 	flag.BoolVar(&help, "h", false, "print a help message and exit")
 	flag.BoolVar(&shouldMatch, "m", false, "all SKIs should match")
 	flag.Parse()
 
+	displayMode := lib.ParseHexEncodeMode(displayModeString)
+
 	if help {
 		usage(os.Stdout)
 		os.Exit(0)
 	}
 
-	var ski string
+	var matchSKI string
 	for _, path := range flag.Args() {
-		public, kt, ft := parse(path)
+		keyInfo, err := ski.ParsePEM(path)
+		die.If(err)
 
-		var subPKI subjectPublicKeyInfo
-		_, err := asn1.Unmarshal(public, &subPKI)
-		if err != nil {
-			_, _ = lib.Warn(err, "failed to get subject PKI")
-			continue
+		keySKI, err := keyInfo.SKI(displayMode)
+		die.If(err)
+
+		if matchSKI == "" {
+			matchSKI = keySKI
 		}
 
-		pubHash := sha1.Sum(subPKI.SubjectPublicKey.Bytes) // #nosec G401 this is the standard
-		pubHashString := dumpHex(pubHash[:])
-		if ski == "" {
-			ski = pubHashString
-		}
-
-		if shouldMatch && ski != pubHashString {
+		if shouldMatch && matchSKI != keySKI {
 			_, _ = lib.Warnx("%s: SKI mismatch (%s != %s)",
-				path, ski, pubHashString)
+				path, matchSKI, keySKI)
 		}
-		fmt.Printf("%s  %s (%s %s)\n", path, pubHashString, kt, ft)
+		fmt.Printf("%s  %s (%s %s)\n", path, keySKI, keyInfo.KeyType, keyInfo.FileType)
 	}
 }

cmd/stealchain/main.go

@@ -3,55 +3,48 @@ package main
 import (
 	"context"
 	"crypto/tls"
-	"crypto/x509"
 	"encoding/pem"
 	"flag"
 	"fmt"
 	"net"
 	"os"
 
+	"git.wntrmute.dev/kyle/goutils/certlib"
 	"git.wntrmute.dev/kyle/goutils/die"
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
 func main() {
-	var cfg = &tls.Config{} // #nosec G402
-
 	var sysRoot, serverName string
+	var skipVerify bool
+	var strictTLS bool
+	lib.StrictTLSFlag(&strictTLS)
 	flag.StringVar(&sysRoot, "ca", "", "provide an alternate CA bundle")
-	flag.StringVar(&cfg.ServerName, "sni", cfg.ServerName, "provide an SNI name")
-	flag.BoolVar(&cfg.InsecureSkipVerify, "noverify", false, "don't verify certificates")
+	flag.StringVar(&serverName, "sni", "", "provide an SNI name")
+	flag.BoolVar(&skipVerify, "noverify", false, "don't verify certificates")
 	flag.Parse()
 
+	tlsCfg, err := lib.BaselineTLSConfig(skipVerify, strictTLS)
+	die.If(err)
+
 	if sysRoot != "" {
-		pemList, err := os.ReadFile(sysRoot)
+		tlsCfg.RootCAs, err = certlib.LoadPEMCertPool(sysRoot)
 		die.If(err)
-
-		roots := x509.NewCertPool()
-		if !roots.AppendCertsFromPEM(pemList) {
-			fmt.Printf("[!] no valid roots found")
-			roots = nil
-		}
-
-		cfg.RootCAs = roots
 	}
 
 	if serverName != "" {
-		cfg.ServerName = serverName
+		tlsCfg.ServerName = serverName
 	}
 
 	for _, site := range flag.Args() {
-		_, _, err := net.SplitHostPort(site)
+		_, _, err = net.SplitHostPort(site)
 		if err != nil {
 			site += ":443"
 		}
-		d := &tls.Dialer{Config: cfg}
-		nc, err := d.DialContext(context.Background(), "tcp", site)
-		die.If(err)
 
-		conn, ok := nc.(*tls.Conn)
-		if !ok {
-			die.With("invalid TLS connection (not a *tls.Conn)")
-		}
+		var conn *tls.Conn
+		conn, err = lib.DialTLS(context.Background(), site, lib.DialerOpts{TLSConfig: tlsCfg})
+		die.If(err)
 
 		cs := conn.ConnectionState()
 		var chain []byte

cmd/tlsinfo/main.go

@@ -9,6 +9,7 @@ import (
 
 	"git.wntrmute.dev/kyle/goutils/certlib/hosts"
 	"git.wntrmute.dev/kyle/goutils/die"
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
 func main() {
@@ -20,18 +21,14 @@ func main() {
 	hostPort, err := hosts.ParseHost(os.Args[1])
 	die.If(err)
 
-	d := &tls.Dialer{Config: &tls.Config{
-		InsecureSkipVerify: true,
-	}} // #nosec G402
-
-	nc, err := d.DialContext(context.Background(), "tcp", hostPort.String())
+	// Use proxy-aware TLS dialer; skip verification as before
+	conn, err := lib.DialTLS(
+		context.Background(),
+		hostPort.String(),
+		lib.DialerOpts{TLSConfig: &tls.Config{InsecureSkipVerify: true}},
+	) // #nosec G402
 	die.If(err)
 
-	conn, ok := nc.(*tls.Conn)
-	if !ok {
-		die.With("invalid TLS connection (not a *tls.Conn)")
-	}
-
 	defer conn.Close()
 
 	state := conn.ConnectionState()

cmd/tlskeypair/main.go

@@ -1,158 +1,15 @@
 package main
 
 import (
-	"bytes"
-	"crypto"
-	"crypto/ecdsa"
-	"crypto/elliptic"
-	"crypto/rsa"
-	"crypto/x509"
-	"encoding/pem"
-	"errors"
 	"flag"
 	"fmt"
 	"os"
 
+	"git.wntrmute.dev/kyle/goutils/certlib"
 	"git.wntrmute.dev/kyle/goutils/die"
 )
 
-var validPEMs = map[string]bool{
-	"PRIVATE KEY":     true,
-	"RSA PRIVATE KEY": true,
-	"EC PRIVATE KEY":  true,
-}
-
-const (
-	curveInvalid = iota // any invalid curve
-	curveRSA            // indicates key is an RSA key, not an EC key
-	curveP256
-	curveP384
-	curveP521
-)
-
-func getECCurve(pub any) int {
-	switch pub := pub.(type) {
-	case *ecdsa.PublicKey:
-		switch pub.Curve {
-		case elliptic.P256():
-			return curveP256
-		case elliptic.P384():
-			return curveP384
-		case elliptic.P521():
-			return curveP521
-		default:
-			return curveInvalid
-		}
-	case *rsa.PublicKey:
-		return curveRSA
-	default:
-		return curveInvalid
-	}
-}
-
-// matchRSA compares an RSA public key from certificate against RSA public key from private key.
-// It returns true on match.
-func matchRSA(certPub *rsa.PublicKey, keyPub *rsa.PublicKey) bool {
-	return keyPub.N.Cmp(certPub.N) == 0 && keyPub.E == certPub.E
-}
-
-// matchECDSA compares ECDSA public keys for equality and compatible curve.
-// It returns match=true when they are on the same curve and have the same X/Y.
-// If curves mismatch, match is false.
-func matchECDSA(certPub *ecdsa.PublicKey, keyPub *ecdsa.PublicKey) bool {
-	if getECCurve(certPub) != getECCurve(keyPub) {
-		return false
-	}
-	if keyPub.X.Cmp(certPub.X) != 0 {
-		return false
-	}
-	if keyPub.Y.Cmp(certPub.Y) != 0 {
-		return false
-	}
-	return true
-}
-
-// matchKeys determines whether the certificate's public key matches the given private key.
-// It returns true if they match; otherwise, it returns false and a human-friendly reason.
-func matchKeys(cert *x509.Certificate, priv crypto.Signer) (bool, string) {
-	switch keyPub := priv.Public().(type) {
-	case *rsa.PublicKey:
-		switch certPub := cert.PublicKey.(type) {
-		case *rsa.PublicKey:
-			if matchRSA(certPub, keyPub) {
-				return true, ""
-			}
-			return false, "public keys don't match"
-		case *ecdsa.PublicKey:
-			return false, "RSA private key, EC public key"
-		default:
-			return false, fmt.Sprintf("unsupported certificate public key type: %T", cert.PublicKey)
-		}
-	case *ecdsa.PublicKey:
-		switch certPub := cert.PublicKey.(type) {
-		case *ecdsa.PublicKey:
-			if matchECDSA(certPub, keyPub) {
-				return true, ""
-			}
-			// Determine a more precise reason
-			kc := getECCurve(keyPub)
-			cc := getECCurve(certPub)
-			if kc == curveInvalid {
-				return false, "invalid private key curve"
-			}
-			if cc == curveRSA {
-				return false, "private key is EC, certificate is RSA"
-			}
-			if kc != cc {
-				return false, "EC curves don't match"
-			}
-			return false, "public keys don't match"
-		case *rsa.PublicKey:
-			return false, "private key is EC, certificate is RSA"
-		default:
-			return false, fmt.Sprintf("unsupported certificate public key type: %T", cert.PublicKey)
-		}
-	default:
-		return false, fmt.Sprintf("unrecognised private key type: %T", priv.Public())
-	}
-}
-
-func loadKey(path string) (crypto.Signer, error) {
-	in, err := os.ReadFile(path)
-	if err != nil {
-		return nil, err
-	}
-
-	in = bytes.TrimSpace(in)
-	p, _ := pem.Decode(in)
-	if p != nil {
-		if !validPEMs[p.Type] {
-			return nil, errors.New("invalid private key file type " + p.Type)
-		}
-		in = p.Bytes
-	}
-
-	priv, err := x509.ParsePKCS8PrivateKey(in)
-	if err != nil {
-		priv, err = x509.ParsePKCS1PrivateKey(in)
-		if err != nil {
-			priv, err = x509.ParseECPrivateKey(in)
-			if err != nil {
-				return nil, err
-			}
-		}
-	}
-
-	switch p := priv.(type) {
-	case *rsa.PrivateKey:
-		return p, nil
-	case *ecdsa.PrivateKey:
-		return p, nil
-	default:
-		// should never reach here
-		return nil, errors.New("invalid private key")
-	}
-}
+// functionality refactored into certlib
 
 func main() {
 	var keyFile, certFile string
@@ -160,23 +17,13 @@ func main() {
 	flag.StringVar(&certFile, "c", "", "TLS `certificate` file")
 	flag.Parse()
 
-	in, err := os.ReadFile(certFile)
+	cert, err := certlib.LoadCertificate(certFile)
 	die.If(err)
 
-	p, _ := pem.Decode(in)
-	if p != nil {
-		if p.Type != "CERTIFICATE" {
-			die.With("invalid certificate (type is %s)", p.Type)
-		}
-		in = p.Bytes
-	}
-	cert, err := x509.ParseCertificate(in)
+	priv, err := certlib.LoadPrivateKey(keyFile)
 	die.If(err)
 
-	priv, err := loadKey(keyFile)
-	die.If(err)
-
-	matched, reason := matchKeys(cert, priv)
+	matched, reason := certlib.MatchKeys(cert, priv)
 	if matched {
 		fmt.Println("Match.")
 		return

dbg/dbg.go

@@ -1,12 +1,34 @@
-// Package dbg implements a debug printer.
+// Package dbg implements a simple debug printer.
+//
+// There are two main ways to use it:
+//   - By using one of the constructors and calling flag.BoolVar(&debug.Enabled...)
+//   - By setting the environment variable GOUTILS_ENABLE_DEBUG to true or false and
+//     calling NewFromEnv().
+//
+// If enabled, any of the print statements will be written to stdout. Otherwise,
+// nothing will be emitted.
 package dbg
 
 import (
 	"fmt"
 	"io"
 	"os"
+	"runtime/debug"
+	"strings"
 )
 
+const DebugEnvKey = "GOUTILS_ENABLE_DEBUG"
+
+var enabledValues = map[string]bool{
+	"1":       true,
+	"true":    true,
+	"yes":     true,
+	"on":      true,
+	"y":       true,
+	"enable":  true,
+	"enabled": true,
+}
+
 // A DebugPrinter is a drop-in replacement for fmt.Print*, and also acts as
 // an io.WriteCloser when enabled.
 type DebugPrinter struct {
@@ -15,6 +37,23 @@ type DebugPrinter struct {
 	out     io.WriteCloser
 }
 
+// New returns a new DebugPrinter on os.Stdout.
+func New() *DebugPrinter {
+	return &DebugPrinter{
+		out: os.Stderr,
+	}
+}
+
+// NewFromEnv returns a new DebugPrinter based on the value of the environment
+// variable GOUTILS_ENABLE_DEBUG.
+func NewFromEnv() *DebugPrinter {
+	enabled := strings.ToLower(os.Getenv(DebugEnvKey))
+	return &DebugPrinter{
+		out:     os.Stderr,
+		Enabled: enabledValues[enabled],
+	}
+}
+
 // Close satisfies the Closer interface.
 func (dbg *DebugPrinter) Close() error {
 	return dbg.out.Close()
@@ -28,13 +67,6 @@ func (dbg *DebugPrinter) Write(p []byte) (int, error) {
 	return 0, nil
 }
 
-// New returns a new DebugPrinter on os.Stdout.
-func New() *DebugPrinter {
-	return &DebugPrinter{
-		out: os.Stdout,
-	}
-}
-
 // ToFile sets up a new DebugPrinter to a file, truncating it if it exists.
 func ToFile(path string) (*DebugPrinter, error) {
 	file, err := os.Create(path)
@@ -74,3 +106,7 @@ func (dbg *DebugPrinter) Printf(format string, v ...any) {
 		fmt.Fprintf(dbg.out, format, v...)
 	}
 }
+
+func (dbg *DebugPrinter) StackTrace() {
+	dbg.Write(debug.Stack())
+}

go.mod

@@ -6,7 +6,8 @@ require (
 	github.com/hashicorp/go-syslog v1.0.0
 	github.com/kr/text v0.2.0
 	github.com/pkg/sftp v1.12.0
-	golang.org/x/crypto v0.44.0
+	golang.org/x/crypto v0.39.0
+	golang.org/x/net v0.38.0
 	golang.org/x/sys v0.38.0
 	gopkg.in/yaml.v2 v2.4.0
 )
@@ -15,6 +16,7 @@ require (
 	github.com/benbjohnson/clock v1.3.5
 	github.com/davecgh/go-spew v1.1.1
 	github.com/google/certificate-transparency-go v1.0.21
+	rsc.io/qr v0.2.0
 )
 
 require (

go.sum

@@ -27,13 +27,19 @@ github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.39.0 h1:SHs+kF4LP+f+p14esP5jAoDpHU8Gu/v9lFRK6IT5imM=
+golang.org/x/crypto v0.39.0/go.mod h1:L+Xg3Wf6HoL4Bn4238Z6ft6KfEpN0tJGo53AAPC632U=
 golang.org/x/crypto v0.44.0 h1:A97SsFvM3AIwEEmTBiaxPPTYpDC47w720rdiiUvgoAU=
 golang.org/x/crypto v0.44.0/go.mod h1:013i+Nw79BMiQiMsOPcVCB5ZIJbYkerPrGnOa00tvmc=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.38.0 h1:vRMAPTMaeGqVhG5QyLJHqNDwecKTomGeqbnfZyKlBI8=
+golang.org/x/net v0.38.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
+golang.org/x/net v0.46.0/go.mod h1:Q9BGdFy1y4nkUwiLvT5qtyhAnEHgnQ/zd8PfU6nc210=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
 golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/term v0.32.0 h1:DR4lr0TjUs3epypdhTOkMmuF5CDFJ/8pOnbzMZPQ7bg=
 golang.org/x/term v0.37.0 h1:8EGAD0qCmHYZg6J17DvsMy9/wJ7/D/4pV/wfnld5lTU=
 golang.org/x/term v0.37.0/go.mod h1:5pB4lxRNYYVZuTLmy8oR2BH8dflOR+IbTYFD8fi3254=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -44,3 +50,5 @@ gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+rsc.io/qr v0.2.0 h1:6vBLea5/NRMVTz8V66gipeLycZMl/+UlFmk8DvqQ6WY=
+rsc.io/qr v0.2.0/go.mod h1:IF+uZjkb9fqyeF/4tlBoynqmQxUoPfWEKh921coOuXs=

lib/defs.go

@@ -11,3 +11,11 @@ const (
 	// ExitFailure is the failing exit status.
 	ExitFailure = 1
 )
+
+const (
+	OneTrueDateFormat    = "2006-01-02T15:04:05-0700"
+	DateShortFormat      = "2006-01-02"
+	TimeShortFormat      = "15:04:05"
+	TimeShorterFormat    = "15:04"
+	TimeStandardDateTime = "2006-01-02 15:04"
+)

lib/dialer.go

@@ -0,0 +1,525 @@
+// Package lib contains reusable helpers. This file provides proxy-aware
+// dialers for plain TCP and TLS connections using environment variables.
+//
+// Supported proxy environment variables (checked case-insensitively):
+//   - SOCKS5_PROXY  (e.g., socks5://user:pass@host:1080)
+//   - HTTPS_PROXY   (e.g., https://user:pass@host:443)
+//   - HTTP_PROXY    (e.g., http://user:pass@host:3128)
+//
+// Precedence when multiple proxies are set (both for net and TLS dialers):
+//  1. SOCKS5_PROXY
+//  2. HTTPS_PROXY
+//  3. HTTP_PROXY
+//
+// Both uppercase and lowercase variable names are honored.
+package lib
+
+import (
+	"bufio"
+	"context"
+	"crypto/tls"
+	"encoding/base64"
+	"errors"
+	"flag"
+	"fmt"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+	"time"
+
+	xproxy "golang.org/x/net/proxy"
+
+	"git.wntrmute.dev/kyle/goutils/dbg"
+)
+
+// StrictBaselineTLSConfig returns a secure TLS config.
+// Many of the tools in this repo are designed to debug broken TLS systems
+// and therefore explicitly support old or insecure TLS setups.
+func StrictBaselineTLSConfig() *tls.Config {
+	return &tls.Config{
+		MinVersion:         tls.VersionTLS12,
+		InsecureSkipVerify: false, // explicitly set
+	}
+}
+
+func StrictTLSFlag(useStrict *bool) {
+	flag.BoolVar(useStrict, "strict-tls", false, "Use strict TLS configuration (disables certificate verification)")
+}
+
+func BaselineTLSConfig(skipVerify bool, secure bool) (*tls.Config, error) {
+	if secure && skipVerify {
+		return nil, errors.New("cannot skip verification and use secure TLS")
+	}
+
+	if skipVerify {
+		return &tls.Config{InsecureSkipVerify: true}, nil // #nosec G402 - intentional
+	}
+
+	if secure {
+		return StrictBaselineTLSConfig(), nil
+	}
+
+	return &tls.Config{}, nil // #nosec G402 - intentional
+}
+
+var debug = dbg.NewFromEnv()
+
+// DialerOpts controls creation of proxy-aware dialers.
+//
+// Timeout controls the maximum amount of time spent establishing the
+// underlying TCP connection and any proxy handshake. If zero, a
+// reasonable default (30s) is used.
+//
+// TLSConfig is used by the TLS dialer to configure the TLS handshake to
+// the target endpoint. If TLSConfig.ServerName is empty, it will be set
+// from the host portion of the address passed to DialContext.
+type DialerOpts struct {
+	Timeout   time.Duration
+	TLSConfig *tls.Config
+}
+
+// ContextDialer matches the common DialContext signature used by net and tls dialers.
+type ContextDialer interface {
+	DialContext(ctx context.Context, network, address string) (net.Conn, error)
+}
+
+// DialTCP is a convenience helper that dials a TCP connection to address
+// using a proxy-aware dialer derived from opts. It honors SOCKS5_PROXY,
+// HTTPS_PROXY, and HTTP_PROXY environment variables.
+func DialTCP(ctx context.Context, address string, opts DialerOpts) (net.Conn, error) {
+	d, err := NewNetDialer(opts)
+	if err != nil {
+		return nil, err
+	}
+	return d.DialContext(ctx, "tcp", address)
+}
+
+// DialTLS is a convenience helper that dials a TLS-wrapped TCP connection to
+// address using a proxy-aware dialer derived from opts. It returns a *tls.Conn.
+// It honors SOCKS5_PROXY, HTTPS_PROXY, and HTTP_PROXY environment variables and
+// uses opts.TLSConfig for the handshake (filling ServerName from address if empty).
+func DialTLS(ctx context.Context, address string, opts DialerOpts) (*tls.Conn, error) {
+	d, err := NewTLSDialer(opts)
+	if err != nil {
+		return nil, err
+	}
+
+	c, err := d.DialContext(ctx, "tcp", address)
+	if err != nil {
+		return nil, err
+	}
+
+	tlsConn, ok := c.(*tls.Conn)
+	if !ok {
+		_ = c.Close()
+		return nil, fmt.Errorf("DialTLS: expected *tls.Conn, got %T", c)
+	}
+	return tlsConn, nil
+}
+
+// NewNetDialer returns a ContextDialer that dials TCP connections using
+// proxies discovered from the environment (SOCKS5_PROXY, HTTPS_PROXY, HTTP_PROXY).
+// The returned dialer supports context cancellation for direct and HTTP(S)
+// proxies and applies the configured timeout to connection/proxy handshake.
+func NewNetDialer(opts DialerOpts) (ContextDialer, error) {
+	if opts.Timeout <= 0 {
+		opts.Timeout = 30 * time.Second
+	}
+
+	if u := getProxyURLFromEnv("SOCKS5_PROXY"); u != nil {
+		debug.Printf("using SOCKS5 proxy %q\n", u)
+		return newSOCKS5Dialer(u, opts)
+	}
+
+	if u := getProxyURLFromEnv("HTTPS_PROXY"); u != nil {
+		// Respect the proxy URL scheme. Zscaler may set HTTPS_PROXY to an HTTP proxy
+		// running locally; in that case we must NOT TLS-wrap the proxy connection.
+		debug.Printf("using HTTPS proxy %q\n", u)
+		return &httpProxyDialer{
+			proxyURL: u,
+			timeout:  opts.Timeout,
+			secure:   strings.EqualFold(u.Scheme, "https"),
+			config:   opts.TLSConfig,
+		}, nil
+	}
+
+	if u := getProxyURLFromEnv("HTTP_PROXY"); u != nil {
+		debug.Printf("using HTTP proxy %q\n", u)
+		return &httpProxyDialer{
+			proxyURL: u,
+			timeout:  opts.Timeout,
+			// Only TLS-wrap the proxy connection if the URL scheme is https.
+			secure: strings.EqualFold(u.Scheme, "https"),
+			config: opts.TLSConfig,
+		}, nil
+	}
+
+	// Direct dialer
+	return &net.Dialer{Timeout: opts.Timeout}, nil
+}
+
+// NewTLSDialer returns a ContextDialer that establishes a TLS connection to
+// the destination, while honoring SOCKS5_PROXY/HTTPS_PROXY/HTTP_PROXY.
+//
+// The returned dialer performs proxy negotiation (if any), then completes a
+// TLS handshake to the target using opts.TLSConfig.
+func NewTLSDialer(opts DialerOpts) (ContextDialer, error) {
+	if opts.Timeout <= 0 {
+		opts.Timeout = 30 * time.Second
+	}
+
+	// Prefer SOCKS5 if present.
+	if u := getProxyURLFromEnv("SOCKS5_PROXY"); u != nil {
+		debug.Printf("using SOCKS5 proxy %q\n", u)
+		base, err := newSOCKS5Dialer(u, opts)
+		if err != nil {
+			return nil, err
+		}
+		return &tlsWrappingDialer{base: base, tcfg: opts.TLSConfig, timeout: opts.Timeout}, nil
+	}
+
+	// For TLS, prefer HTTPS proxy over HTTP if both set.
+	if u := getProxyURLFromEnv("HTTPS_PROXY"); u != nil {
+		debug.Printf("using HTTPS proxy %q\n", u)
+		base := &httpProxyDialer{
+			proxyURL: u,
+			timeout:  opts.Timeout,
+			secure:   strings.EqualFold(u.Scheme, "https"),
+			config:   opts.TLSConfig,
+		}
+		return &tlsWrappingDialer{base: base, tcfg: opts.TLSConfig, timeout: opts.Timeout}, nil
+	}
+
+	if u := getProxyURLFromEnv("HTTP_PROXY"); u != nil {
+		debug.Printf("using HTTP proxy %q\n", u)
+		base := &httpProxyDialer{
+			proxyURL: u,
+			timeout:  opts.Timeout,
+			secure:   strings.EqualFold(u.Scheme, "https"),
+			config:   opts.TLSConfig,
+		}
+		return &tlsWrappingDialer{base: base, tcfg: opts.TLSConfig, timeout: opts.Timeout}, nil
+	}
+
+	// Direct TLS
+	base := &net.Dialer{Timeout: opts.Timeout}
+	return &tlsWrappingDialer{base: base, tcfg: opts.TLSConfig, timeout: opts.Timeout}, nil
+}
+
+// ---- Implementation helpers ----
+
+func getProxyURLFromEnv(name string) *url.URL {
+	// check both upper/lowercase
+	v := os.Getenv(name)
+	if v == "" {
+		v = os.Getenv(strings.ToLower(name))
+	}
+	if v == "" {
+		return nil
+	}
+	// If scheme omitted, infer from env var name.
+	if !strings.Contains(v, "://") {
+		switch strings.ToUpper(name) {
+		case "SOCKS5_PROXY":
+			v = "socks5://" + v
+		case "HTTPS_PROXY":
+			v = "https://" + v
+		default:
+			v = "http://" + v
+		}
+	}
+	u, err := url.Parse(v)
+	if err != nil {
+		return nil
+	}
+	return u
+}
+
+// NewHTTPClient returns an *http.Client that is proxy-aware.
+//
+// Behavior:
+//   - If SOCKS5_PROXY is set, the client routes all TCP connections through the
+//     SOCKS5 proxy using a custom DialContext, and disables HTTP(S) proxying in
+//     the transport (per our precedence SOCKS5 > HTTPS > HTTP).
+//   - Otherwise, it uses http.ProxyFromEnvironment which supports HTTP_PROXY,
+//     HTTPS_PROXY, and NO_PROXY/no_proxy.
+//   - Connection and TLS handshake timeouts are derived from opts.Timeout.
+//   - For HTTPS targets, opts.TLSConfig is applied to the transport.
+func NewHTTPClient(opts DialerOpts) (*http.Client, error) {
+	if opts.Timeout <= 0 {
+		opts.Timeout = 30 * time.Second
+	}
+
+	// Base transport configuration
+	tr := &http.Transport{
+		TLSClientConfig:     opts.TLSConfig,
+		TLSHandshakeTimeout: opts.Timeout,
+		// Leave other fields as Go defaults for compatibility.
+	}
+
+	// If SOCKS5 is configured, use our dialer and disable HTTP proxying to
+	// avoid double-proxying. Otherwise, rely on ProxyFromEnvironment for
+	// HTTP(S) proxies and still set a connect timeout via net.Dialer.
+	if u := getProxyURLFromEnv("SOCKS5_PROXY"); u != nil {
+		d, err := newSOCKS5Dialer(u, opts)
+		if err != nil {
+			return nil, err
+		}
+		tr.Proxy = nil
+		tr.DialContext = func(ctx context.Context, network, address string) (net.Conn, error) {
+			return d.DialContext(ctx, network, address)
+		}
+	} else {
+		tr.Proxy = http.ProxyFromEnvironment
+		// Use a standard net.Dialer to ensure we apply a connect timeout.
+		nd := &net.Dialer{Timeout: opts.Timeout}
+		tr.DialContext = nd.DialContext
+	}
+
+	// Construct client; we don't set Client.Timeout here to avoid affecting
+	// streaming responses. Callers can set it if they want an overall deadline.
+	return &http.Client{Transport: tr}, nil
+}
+
+// httpProxyDialer implements CONNECT tunneling over HTTP or HTTPS proxy.
+type httpProxyDialer struct {
+	proxyURL *url.URL
+	timeout  time.Duration
+	secure   bool // true for HTTPS proxy
+	config   *tls.Config
+}
+
+// proxyAddress returns host:port for the proxy, applying defaults by scheme when missing.
+func (d *httpProxyDialer) proxyAddress() string {
+	proxyAddr := d.proxyURL.Host
+	if !strings.Contains(proxyAddr, ":") {
+		if d.secure {
+			proxyAddr += ":443"
+		} else {
+			proxyAddr += ":80"
+		}
+	}
+	return proxyAddr
+}
+
+// tlsWrapProxyConn performs a TLS handshake to the proxy when d.secure is true.
+// It clones the provided tls.Config (if any), ensures ServerName and a safe
+// minimum TLS version.
+func (d *httpProxyDialer) tlsWrapProxyConn(ctx context.Context, conn net.Conn) (net.Conn, error) {
+	host := d.proxyURL.Hostname()
+	// Clone provided config (if any) to avoid mutating caller's config.
+	cfg := &tls.Config{} // #nosec G402 - intentional
+	if d.config != nil {
+		cfg = d.config.Clone()
+	}
+
+	if cfg.ServerName == "" {
+		cfg.ServerName = host
+	}
+
+	tlsConn := tls.Client(conn, cfg)
+	if err := tlsConn.HandshakeContext(ctx); err != nil {
+		_ = conn.Close()
+		return nil, fmt.Errorf("tls handshake with https proxy failed: %w", err)
+	}
+	return tlsConn, nil
+}
+
+// readConnectResponse reads and validates the proxy's response to a CONNECT
+// request. It returns nil on a 200 status and an error otherwise.
+func readConnectResponse(br *bufio.Reader) error {
+	statusLine, err := br.ReadString('\n')
+	if err != nil {
+		return fmt.Errorf("failed to read CONNECT response: %w", err)
+	}
+
+	if !strings.HasPrefix(statusLine, "HTTP/") {
+		return fmt.Errorf("invalid proxy response: %q", strings.TrimSpace(statusLine))
+	}
+
+	if !strings.Contains(statusLine, " 200 ") && !strings.HasSuffix(strings.TrimSpace(statusLine), " 200") {
+		// Drain headers for context
+		_ = drainHeaders(br)
+		return fmt.Errorf("proxy CONNECT failed: %s", strings.TrimSpace(statusLine))
+	}
+
+	return drainHeaders(br)
+}
+
+func (d *httpProxyDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	if !strings.HasPrefix(network, "tcp") {
+		return nil, fmt.Errorf("http proxy dialer only supports TCP, got %q", network)
+	}
+
+	// Dial to proxy
+	var nd = &net.Dialer{Timeout: d.timeout}
+	conn, err := nd.DialContext(ctx, "tcp", d.proxyAddress())
+	if err != nil {
+		return nil, err
+	}
+
+	// Deadline covering CONNECT and (for TLS wrapper) will be handled by caller too.
+	if d.timeout > 0 {
+		_ = conn.SetDeadline(time.Now().Add(d.timeout))
+	}
+
+	// If HTTPS proxy, wrap with TLS to the proxy itself.
+	if d.secure {
+		c, werr := d.tlsWrapProxyConn(ctx, conn)
+		if werr != nil {
+			return nil, werr
+		}
+		conn = c
+	}
+
+	req := buildConnectRequest(d.proxyURL, address)
+	if _, err = conn.Write([]byte(req)); err != nil {
+		_ = conn.Close()
+		return nil, fmt.Errorf("failed to write CONNECT request: %w", err)
+	}
+
+	// Read proxy response until end of headers
+	br := bufio.NewReader(conn)
+	if err = readConnectResponse(br); err != nil {
+		_ = conn.Close()
+		return nil, err
+	}
+
+	// Clear deadline for caller to manage further I/O.
+	_ = conn.SetDeadline(time.Time{})
+	return conn, nil
+}
+
+func buildConnectRequest(proxyURL *url.URL, target string) string {
+	var b strings.Builder
+	fmt.Fprintf(&b, "CONNECT %s HTTP/1.1\r\n", target)
+	fmt.Fprintf(&b, "Host: %s\r\n", target)
+	b.WriteString("Proxy-Connection: Keep-Alive\r\n")
+	b.WriteString("User-Agent: goutils-dialer/1\r\n")
+
+	if proxyURL.User != nil {
+		user := proxyURL.User.Username()
+		pass, _ := proxyURL.User.Password()
+		auth := base64.StdEncoding.EncodeToString([]byte(user + ":" + pass))
+		fmt.Fprintf(&b, "Proxy-Authorization: Basic %s\r\n", auth)
+	}
+	b.WriteString("\r\n")
+	return b.String()
+}
+
+func drainHeaders(br *bufio.Reader) error {
+	for {
+		line, err := br.ReadString('\n')
+		if err != nil {
+			return fmt.Errorf("reading proxy headers: %w", err)
+		}
+		if line == "\r\n" || line == "\n" {
+			return nil
+		}
+	}
+}
+
+// newSOCKS5Dialer builds a context-aware wrapper over the x/net/proxy dialer.
+func newSOCKS5Dialer(u *url.URL, opts DialerOpts) (ContextDialer, error) {
+	var auth *xproxy.Auth
+	if u.User != nil {
+		user := u.User.Username()
+		pass, _ := u.User.Password()
+		auth = &xproxy.Auth{User: user, Password: pass}
+	}
+	forward := &net.Dialer{Timeout: opts.Timeout}
+	d, err := xproxy.SOCKS5("tcp", hostPortWithDefault(u, "1080"), auth, forward)
+	if err != nil {
+		return nil, err
+	}
+	return &socks5ContextDialer{d: d, timeout: opts.Timeout}, nil
+}
+
+type socks5ContextDialer struct {
+	d       xproxy.Dialer // lacks context; we wrap it
+	timeout time.Duration
+}
+
+func (s *socks5ContextDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	if !strings.HasPrefix(network, "tcp") {
+		return nil, errors.New("socks5 dialer only supports TCP")
+	}
+	// Best-effort context support: run the non-context dial in a goroutine
+	// and respect ctx cancellation/timeout.
+	type result struct {
+		c   net.Conn
+		err error
+	}
+	ch := make(chan result, 1)
+	go func() {
+		c, err := s.d.Dial("tcp", address)
+		ch <- result{c: c, err: err}
+	}()
+
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case r := <-ch:
+		return r.c, r.err
+	}
+}
+
+// tlsWrappingDialer performs a TLS handshake over an existing base dialer.
+type tlsWrappingDialer struct {
+	base    ContextDialer
+	tcfg    *tls.Config
+	timeout time.Duration
+}
+
+func (t *tlsWrappingDialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	if !strings.HasPrefix(network, "tcp") {
+		return nil, fmt.Errorf("tls dialer only supports TCP, got %q", network)
+	}
+	raw, err := t.base.DialContext(ctx, network, address)
+	if err != nil {
+		return nil, err
+	}
+
+	// Apply deadline for handshake.
+	if t.timeout > 0 {
+		_ = raw.SetDeadline(time.Now().Add(t.timeout))
+	}
+
+	var h string
+	host := address
+
+	if h, _, err = net.SplitHostPort(address); err == nil {
+		host = h
+	}
+	var cfg *tls.Config
+	if t.tcfg != nil {
+		// Clone to avoid copying internal locks and to prevent mutating caller's config.
+		c := t.tcfg.Clone()
+		if c.ServerName == "" {
+			c.ServerName = host
+		}
+		cfg = c
+	} else {
+		cfg = &tls.Config{ServerName: host, MinVersion: tls.VersionTLS12}
+	}
+
+	tlsConn := tls.Client(raw, cfg)
+	if err = tlsConn.HandshakeContext(ctx); err != nil {
+		_ = raw.Close()
+		return nil, err
+	}
+
+	// Clear deadline after successful handshake
+	_ = tlsConn.SetDeadline(time.Time{})
+	return tlsConn, nil
+}
+
+func hostPortWithDefault(u *url.URL, defPort string) string {
+	host := u.Host
+	if !strings.Contains(host, ":") {
+		host += ":" + defPort
+	}
+	return host
+}

lib/fetch.go

@@ -0,0 +1,165 @@
+package lib
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"io"
+	"net"
+	"os"
+
+	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/hosts"
+	"git.wntrmute.dev/kyle/goutils/fileutil"
+)
+
+// Note: Previously this package exposed a FetcherOpts type. It has been
+// refactored to use *tls.Config directly for configuring TLS behavior.
+
+// Fetcher is an interface for fetching certificates from a remote source. It
+// currently supports fetching from a server or a file.
+type Fetcher interface {
+	Get() (*x509.Certificate, error)
+	GetChain() ([]*x509.Certificate, error)
+	String() string
+}
+
+type ServerFetcher struct {
+	host     string
+	port     int
+	insecure bool
+	roots    *x509.CertPool
+}
+
+// WithRoots sets the roots for the ServerFetcher.
+func WithRoots(roots *x509.CertPool) func(*ServerFetcher) {
+	return func(sf *ServerFetcher) {
+		sf.roots = roots
+	}
+}
+
+// WithSkipVerify sets the insecure flag for the ServerFetcher.
+func WithSkipVerify() func(*ServerFetcher) {
+	return func(sf *ServerFetcher) {
+		sf.insecure = true
+	}
+}
+
+// ParseServer parses a server string into a ServerFetcher. It can be a URL or a
+// a host:port pair.
+func ParseServer(host string) (*ServerFetcher, error) {
+	target, err := hosts.ParseHost(host)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse server: %w", err)
+	}
+
+	return &ServerFetcher{
+		host: target.Host,
+		port: target.Port,
+	}, nil
+}
+
+func (sf *ServerFetcher) String() string {
+	return fmt.Sprintf("tls://%s", net.JoinHostPort(sf.host, Itoa(sf.port, -1)))
+}
+
+func (sf *ServerFetcher) GetChain() ([]*x509.Certificate, error) {
+	opts := DialerOpts{
+		TLSConfig: &tls.Config{
+			InsecureSkipVerify: sf.insecure, // #nosec G402 - no shit sherlock
+			RootCAs:            sf.roots,
+		},
+	}
+
+	conn, err := DialTLS(context.Background(), net.JoinHostPort(sf.host, Itoa(sf.port, -1)), opts)
+	if err != nil {
+		return nil, fmt.Errorf("failed to dial server: %w", err)
+	}
+	defer conn.Close()
+
+	state := conn.ConnectionState()
+	return state.PeerCertificates, nil
+}
+
+func (sf *ServerFetcher) Get() (*x509.Certificate, error) {
+	certs, err := sf.GetChain()
+	if err != nil {
+		return nil, err
+	}
+
+	return certs[0], nil
+}
+
+type FileFetcher struct {
+	path string
+}
+
+func NewFileFetcher(path string) *FileFetcher {
+	return &FileFetcher{
+		path: path,
+	}
+}
+
+func (ff *FileFetcher) String() string {
+	return ff.path
+}
+
+func (ff *FileFetcher) GetChain() ([]*x509.Certificate, error) {
+	if ff.path == "-" {
+		certData, err := io.ReadAll(os.Stdin)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read from stdin: %w", err)
+		}
+
+		return certlib.ParseCertificatesPEM(certData)
+	}
+
+	certs, err := certlib.LoadCertificates(ff.path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load chain: %w", err)
+	}
+
+	return certs, nil
+}
+
+func (ff *FileFetcher) Get() (*x509.Certificate, error) {
+	certs, err := ff.GetChain()
+	if err != nil {
+		return nil, err
+	}
+
+	return certs[0], nil
+}
+
+// GetCertificateChain fetches a certificate chain from a remote source.
+// If cfg is non-nil and spec refers to a TLS server, the provided TLS
+// configuration will be used to control verification behavior (e.g.,
+// InsecureSkipVerify, RootCAs).
+func GetCertificateChain(spec string, cfg *tls.Config) ([]*x509.Certificate, error) {
+	if fileutil.FileDoesExist(spec) {
+		return NewFileFetcher(spec).GetChain()
+	}
+
+	fetcher, err := ParseServer(spec)
+	if err != nil {
+		return nil, err
+	}
+
+	if cfg != nil {
+		fetcher.insecure = cfg.InsecureSkipVerify
+		fetcher.roots = cfg.RootCAs
+	}
+
+	return fetcher.GetChain()
+}
+
+// GetCertificate fetches the first certificate from a certificate chain.
+func GetCertificate(spec string, cfg *tls.Config) (*x509.Certificate, error) {
+	certs, err := GetCertificateChain(spec, cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return certs[0], nil
+}

lib/lib.go

@@ -1,10 +1,12 @@
-// Package lib contains functions useful for most programs.
 package lib
 
 import (
+	"encoding/base64"
+	"encoding/hex"
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 )
 
@@ -109,3 +111,137 @@ func Duration(d time.Duration) string {
 	s += fmt.Sprintf("%dh%s", hours, d)
 	return s
 }
+
+type HexEncodeMode uint8
+
+const (
+	// HexEncodeLower prints the bytes as lowercase hexadecimal.
+	HexEncodeLower HexEncodeMode = iota + 1
+	// HexEncodeUpper prints the bytes as uppercase hexadecimal.
+	HexEncodeUpper
+	// HexEncodeLowerColon prints the bytes as lowercase hexadecimal
+	// with colons between each pair of bytes.
+	HexEncodeLowerColon
+	// HexEncodeUpperColon prints the bytes as uppercase hexadecimal
+	// with colons between each pair of bytes.
+	HexEncodeUpperColon
+	// HexEncodeBytes prints the string as a sequence of []byte.
+	HexEncodeBytes
+	// HexEncodeBase64 prints the string as a base64-encoded string.
+	HexEncodeBase64
+)
+
+func (m HexEncodeMode) String() string {
+	switch m {
+	case HexEncodeLower:
+		return "lower"
+	case HexEncodeUpper:
+		return "upper"
+	case HexEncodeLowerColon:
+		return "lcolon"
+	case HexEncodeUpperColon:
+		return "ucolon"
+	case HexEncodeBytes:
+		return "bytes"
+	case HexEncodeBase64:
+		return "base64"
+	default:
+		panic("invalid hex encode mode")
+	}
+}
+
+func ParseHexEncodeMode(s string) HexEncodeMode {
+	switch strings.ToLower(s) {
+	case "lower":
+		return HexEncodeLower
+	case "upper":
+		return HexEncodeUpper
+	case "lcolon":
+		return HexEncodeLowerColon
+	case "ucolon":
+		return HexEncodeUpperColon
+	case "bytes":
+		return HexEncodeBytes
+	case "base64":
+		return HexEncodeBase64
+	}
+
+	panic("invalid hex encode mode")
+}
+
+func hexColons(s string) string {
+	if len(s)%2 != 0 {
+		fmt.Fprintf(os.Stderr, "hex string: %s\n", s)
+		fmt.Fprintf(os.Stderr, "hex length: %d\n", len(s))
+		panic("invalid hex string length")
+	}
+
+	n := len(s)
+	if n <= 2 {
+		return s
+	}
+
+	pairCount := n / 2
+	if n%2 != 0 {
+		pairCount++
+	}
+
+	var b strings.Builder
+	b.Grow(n + pairCount - 1)
+
+	for i := 0; i < n; i += 2 {
+		b.WriteByte(s[i])
+
+		if i+1 < n {
+			b.WriteByte(s[i+1])
+		}
+
+		if i+2 < n {
+			b.WriteByte(':')
+		}
+	}
+
+	return b.String()
+}
+
+func hexEncode(b []byte) string {
+	s := hex.EncodeToString(b)
+
+	if len(s)%2 != 0 {
+		s = "0" + s
+	}
+
+	return s
+}
+
+func bytesAsByteSliceString(buf []byte) string {
+	sb := &strings.Builder{}
+	sb.WriteString("[]byte{")
+	for i := range buf {
+		fmt.Fprintf(sb, "0x%02x, ", buf[i])
+	}
+	sb.WriteString("}")
+
+	return sb.String()
+}
+
+// HexEncode encodes the given bytes as a hexadecimal string. It
+// also supports a few other binary-encoding formats as well.
+func HexEncode(b []byte, mode HexEncodeMode) string {
+	switch mode {
+	case HexEncodeLower:
+		return hexEncode(b)
+	case HexEncodeUpper:
+		return strings.ToUpper(hexEncode(b))
+	case HexEncodeLowerColon:
+		return hexColons(hexEncode(b))
+	case HexEncodeUpperColon:
+		return strings.ToUpper(hexColons(hexEncode(b)))
+	case HexEncodeBytes:
+		return bytesAsByteSliceString(b)
+	case HexEncodeBase64:
+		return base64.StdEncoding.EncodeToString(b)
+	default:
+		panic("invalid hex encode mode")
+	}
+}

lib/lib_test.go

@@ -0,0 +1,79 @@
+package lib_test
+
+import (
+	"testing"
+
+	"git.wntrmute.dev/kyle/goutils/lib"
+)
+
+func TestHexEncode_LowerUpper(t *testing.T) {
+	b := []byte{0x0f, 0xa1, 0x00, 0xff}
+
+	gotLower := lib.HexEncode(b, lib.HexEncodeLower)
+	if gotLower != "0fa100ff" {
+		t.Fatalf("lib.HexEncode lower: expected %q, got %q", "0fa100ff", gotLower)
+	}
+
+	gotUpper := lib.HexEncode(b, lib.HexEncodeUpper)
+	if gotUpper != "0FA100FF" {
+		t.Fatalf("lib.HexEncode upper: expected %q, got %q", "0FA100FF", gotUpper)
+	}
+}
+
+func TestHexEncode_ColonModes(t *testing.T) {
+	// Includes leading zero nibble and a zero byte to verify padding and separators
+	b := []byte{0x0f, 0xa1, 0x00, 0xff}
+
+	gotLColon := lib.HexEncode(b, lib.HexEncodeLowerColon)
+	if gotLColon != "0f:a1:00:ff" {
+		t.Fatalf("lib.HexEncode colon lower: expected %q, got %q", "0f:a1:00:ff", gotLColon)
+	}
+
+	gotUColon := lib.HexEncode(b, lib.HexEncodeUpperColon)
+	if gotUColon != "0F:A1:00:FF" {
+		t.Fatalf("lib.HexEncode colon upper: expected %q, got %q", "0F:A1:00:FF", gotUColon)
+	}
+}
+
+func TestHexEncode_EmptyInput(t *testing.T) {
+	var b []byte
+	if got := lib.HexEncode(b, lib.HexEncodeLower); got != "" {
+		t.Fatalf("empty lower: expected empty string, got %q", got)
+	}
+	if got := lib.HexEncode(b, lib.HexEncodeUpper); got != "" {
+		t.Fatalf("empty upper: expected empty string, got %q", got)
+	}
+	if got := lib.HexEncode(b, lib.HexEncodeLowerColon); got != "" {
+		t.Fatalf("empty colon lower: expected empty string, got %q", got)
+	}
+	if got := lib.HexEncode(b, lib.HexEncodeUpperColon); got != "" {
+		t.Fatalf("empty colon upper: expected empty string, got %q", got)
+	}
+}
+
+func TestHexEncode_SingleByte(t *testing.T) {
+	b := []byte{0x0f}
+	if got := lib.HexEncode(b, lib.HexEncodeLower); got != "0f" {
+		t.Fatalf("single byte lower: expected %q, got %q", "0f", got)
+	}
+	if got := lib.HexEncode(b, lib.HexEncodeUpper); got != "0F" {
+		t.Fatalf("single byte upper: expected %q, got %q", "0F", got)
+	}
+	// For a single byte, colon modes should not introduce separators
+	if got := lib.HexEncode(b, lib.HexEncodeLowerColon); got != "0f" {
+		t.Fatalf("single byte colon lower: expected %q, got %q", "0f", got)
+	}
+	if got := lib.HexEncode(b, lib.HexEncodeUpperColon); got != "0F" {
+		t.Fatalf("single byte colon upper: expected %q, got %q", "0F", got)
+	}
+}
+
+func TestHexEncode_InvalidModePanics(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Fatalf("expected panic for invalid mode, but function returned normally")
+		}
+	}()
+	// 0 is not a valid lib.HexEncodeMode (valid modes start at 1)
+	_ = lib.HexEncode([]byte{0x01}, lib.HexEncodeMode(0))
+}

release-docker.sh

@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+
+# Release Docker image for kisom/goutils using the Dockerfile in the repo root.
+#
+# Behavior:
+# - Determines the git tag that points to HEAD. If no tag points to HEAD, aborts.
+# - Builds the Docker image from the top-level Dockerfile.
+# - Tags the image as kisom/goutils:<TAG> and kisom/goutils:latest.
+# - Pushes both tags.
+#
+# Usage:
+#   ./release-docker.sh
+
+set -euo pipefail
+
+err() { printf "Error: %s\n" "$*" >&2; }
+info() { printf "==> %s\n" "$*"; }
+
+# Ensure we're inside a git repository and operate from the repo root.
+if ! REPO_ROOT=$(git rev-parse --show-toplevel 2>/dev/null); then
+  err "This script must be run within a git repository."
+  exit 1
+fi
+cd "$REPO_ROOT"
+
+IMAGE_REPO="kisom/goutils"
+DOCKERFILE_PATH="$REPO_ROOT/Dockerfile"
+
+if [[ ! -f "$DOCKERFILE_PATH" ]]; then
+  err "Dockerfile not found at repository root: $DOCKERFILE_PATH"
+  err "Create a top-level Dockerfile or adjust this script before releasing."
+  exit 1
+fi
+
+# Find tags that point to HEAD.
+if ! TAGS=$(git tag --points-at HEAD); then
+  err "Unable to query git tags."
+  exit 1
+fi
+
+if [[ -z "$TAGS" ]]; then
+  err "No git tag points at HEAD. Aborting release."
+  exit 1
+fi
+
+# Use the first tag if multiple are present; warn the user.
+# Avoid readarray for broader Bash compatibility (e.g., macOS Bash 3.2).
+TAG_ARRAY=("$TAGS")
+TAG="${TAG_ARRAY[0]}"
+
+if (( ${#TAG_ARRAY[@]} > 1 )); then
+  info "Multiple tags point at HEAD: ${TAG_ARRAY[*]}"
+  info "Using first tag: $TAG"
+fi
+
+info "Releasing Docker image for tag: $TAG"
+
+IMAGE_TAGGED="$IMAGE_REPO:$TAG"
+IMAGE_LATEST="$IMAGE_REPO:latest"
+
+info "Building image from $DOCKERFILE_PATH"
+docker build -f "$DOCKERFILE_PATH" -t "$IMAGE_TAGGED" -t "$IMAGE_LATEST" "$REPO_ROOT"
+
+info "Pushing $IMAGE_TAGGED"
+docker push "$IMAGE_TAGGED"
+
+info "Pushing $IMAGE_LATEST"
+docker push "$IMAGE_LATEST"
+
+info "Release complete."

twofactor/README.md

@@ -0,0 +1,33 @@
+## `twofactor`
+
+[![GoDoc](https://godoc.org/github.com/gokyle/twofactor?status.svg)](https://godoc.org/github.com/gokyle/twofactor)
+
+
+### Author
+
+`twofactor` was written by Kyle Isom <kyle@tyrfingr.is>.
+
+
+### License
+
+```
+Copyright (c) 2017 Kyle Isom <kyle@imap.cc>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+```

twofactor/doc.go

@@ -0,0 +1,5 @@
+// Package twofactor implements two-factor authentication.
+//
+// Currently supported are RFC 4226 HOTP one-time passwords and
+// RFC 6238 TOTP SHA-1 one-time passwords.
+package twofactor

twofactor/hotp.go

@@ -0,0 +1,103 @@
+package twofactor
+
+import (
+	"crypto"
+	"crypto/sha1" // #nosec G505 - required by RFC
+	"encoding/base32"
+	"io"
+	"net/url"
+	"strconv"
+	"strings"
+)
+
+// HOTP represents an RFC-4226 Hash-based One Time Password instance.
+type HOTP struct {
+	*OATH
+}
+
+// NewHOTP takes the key, the initial counter value, and the number
+// of digits (typically 6 or 8) and returns a new HOTP instance.
+func NewHOTP(key []byte, counter uint64, digits int) *HOTP {
+	return &HOTP{
+		OATH: &OATH{
+			key:     key,
+			counter: counter,
+			size:    digits,
+			hash:    sha1.New,
+			algo:    crypto.SHA1,
+		},
+	}
+}
+
+// Type returns OATH_HOTP.
+func (otp *HOTP) Type() Type {
+	return OATH_HOTP
+}
+
+// OTP returns the next OTP and increments the counter.
+func (otp *HOTP) OTP() string {
+	code := otp.OATH.OTP(otp.counter)
+	otp.counter++
+	return code
+}
+
+// URL returns an HOTP URL (i.e. for putting in a QR code).
+func (otp *HOTP) URL(label string) string {
+	return otp.OATH.URL(otp.Type(), label)
+}
+
+// SetProvider sets up the provider component of the OTP URL.
+func (otp *HOTP) SetProvider(provider string) {
+	otp.provider = provider
+}
+
+// GenerateGoogleHOTP generates a new HOTP instance as used by
+// Google Authenticator.
+func GenerateGoogleHOTP() *HOTP {
+	key := make([]byte, sha1.Size)
+	if _, err := io.ReadFull(PRNG, key); err != nil {
+		return nil
+	}
+	return NewHOTP(key, 0, 6)
+}
+
+func hotpFromURL(u *url.URL) (*HOTP, string, error) {
+	label := u.Path[1:]
+	v := u.Query()
+
+	secret := strings.ToUpper(v.Get("secret"))
+	if secret == "" {
+		return nil, "", ErrInvalidURL
+	}
+
+	var digits = 6
+	if sdigit := v.Get("digits"); sdigit != "" {
+		tmpDigits, err := strconv.ParseInt(sdigit, 10, 8)
+		if err != nil {
+			return nil, "", err
+		}
+		digits = int(tmpDigits)
+	}
+
+	var counter uint64
+	if scounter := v.Get("counter"); scounter != "" {
+		var err error
+		counter, err = strconv.ParseUint(scounter, 10, 64)
+		if err != nil {
+			return nil, "", err
+		}
+	}
+
+	key, err := base32.StdEncoding.DecodeString(Pad(secret))
+	if err != nil {
+		// assume secret isn't base32 encoded
+		key = []byte(secret)
+	}
+	otp := NewHOTP(key, counter, digits)
+	return otp, label, nil
+}
+
+// QR generates a new QR code for the HOTP.
+func (otp *HOTP) QR(label string) ([]byte, error) {
+	return otp.OATH.QR(otp.Type(), label)
+}

twofactor/hotp_internal_test.go

@@ -0,0 +1,58 @@
+package twofactor
+
+import (
+	"testing"
+)
+
+var testKey = []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}
+
+var rfcHotpKey = []byte("12345678901234567890")
+var rfcHotpExpected = []string{
+	"755224",
+	"287082",
+	"359152",
+	"969429",
+	"338314",
+	"254676",
+	"287922",
+	"162583",
+	"399871",
+	"520489",
+}
+
+// This test runs through the test cases presented in the RFC, and
+// ensures that this implementation is in compliance.
+func TestHotpRFC(t *testing.T) {
+	otp := NewHOTP(rfcHotpKey, 0, 6)
+	for i := range rfcHotpExpected {
+		if otp.Counter() != uint64(i) {
+			t.Fatalf("twofactor: invalid counter (should be %d, is %d",
+				i, otp.Counter())
+		}
+		code := otp.OTP()
+		if code == "" {
+			t.Fatal("twofactor: failed to produce an OTP")
+		} else if code != rfcHotpExpected[i] {
+			t.Logf("twofactor: invalid OTP\n")
+			t.Logf("\tExpected: %s\n", rfcHotpExpected[i])
+			t.Logf("\t  Actual: %s\n", code)
+			t.Fatalf("\t Counter: %d\n", otp.counter)
+		}
+	}
+}
+
+// This test uses a different key than the test cases in the RFC,
+// but runs through the same test cases to ensure that they fail as
+// expected.
+func TestHotpBadRFC(t *testing.T) {
+	otp := NewHOTP(testKey, 0, 6)
+	for i := range rfcHotpExpected {
+		code := otp.OTP()
+		switch code {
+		case "":
+			t.Error("twofactor: failed to produce an OTP")
+		case rfcHotpExpected[i]:
+			t.Error("twofactor: should not have received a valid OTP")
+		}
+	}
+}

twofactor/oath.go

@@ -0,0 +1,150 @@
+package twofactor
+
+import (
+	"crypto"
+	"crypto/hmac"
+	"encoding/base32"
+	"encoding/binary"
+	"fmt"
+	"hash"
+	"net/url"
+	"strconv"
+
+	"rsc.io/qr"
+)
+
+const defaultSize = 6
+
+// OATH provides a baseline structure for the two OATH algorithms.
+type OATH struct {
+	key      []byte
+	counter  uint64
+	size     int
+	hash     func() hash.Hash
+	algo     crypto.Hash
+	provider string
+}
+
+// Size returns the output size (in characters) of the password.
+func (o *OATH) Size() int {
+	return o.size
+}
+
+// Counter returns the OATH token's counter.
+func (o *OATH) Counter() uint64 {
+	return o.counter
+}
+
+// SetCounter updates the OATH token's counter to a new value.
+func (o *OATH) SetCounter(counter uint64) {
+	o.counter = counter
+}
+
+// Key returns the token's secret key.
+func (o *OATH) Key() []byte {
+	return o.key
+}
+
+// Hash returns the token's hash function.
+func (o *OATH) Hash() func() hash.Hash {
+	return o.hash
+}
+
+// URL constructs a URL appropriate for the token (i.e. for use in a
+// QR code).
+func (o *OATH) URL(t Type, label string) string {
+	secret := base32.StdEncoding.EncodeToString(o.key)
+	u := url.URL{}
+	v := url.Values{}
+	u.Scheme = "otpauth"
+	switch t {
+	case OATH_HOTP:
+		u.Host = "hotp"
+	case OATH_TOTP:
+		u.Host = "totp"
+	}
+	u.Path = label
+	v.Add("secret", secret)
+	if o.Counter() != 0 && t == OATH_HOTP {
+		v.Add("counter", strconv.FormatUint(o.Counter(), 10))
+	}
+	if o.Size() != defaultSize {
+		v.Add("digits", strconv.Itoa(o.Size()))
+	}
+
+	switch o.algo {
+	case crypto.SHA256:
+		v.Add("algorithm", "SHA256")
+	case crypto.SHA512:
+		v.Add("algorithm", "SHA512")
+	}
+
+	if o.provider != "" {
+		v.Add("provider", o.provider)
+	}
+
+	u.RawQuery = v.Encode()
+	return u.String()
+}
+
+var digits = []int64{
+	0:  1,
+	1:  10,
+	2:  100,
+	3:  1000,
+	4:  10000,
+	5:  100000,
+	6:  1000000,
+	7:  10000000,
+	8:  100000000,
+	9:  1000000000,
+	10: 10000000000,
+}
+
+// OTP top-level type should provide a counter; for example, HOTP
+// will provide the counter directly while TOTP will provide the
+// time-stepped counter.
+func (o *OATH) OTP(counter uint64) string {
+	var ctr [8]byte
+	binary.BigEndian.PutUint64(ctr[:], counter)
+
+	var mod int64 = 1
+	if len(digits) > o.size {
+		for i := 1; i <= o.size; i++ {
+			mod *= 10
+		}
+	} else {
+		mod = digits[o.size]
+	}
+
+	h := hmac.New(o.hash, o.key)
+	h.Write(ctr[:])
+	dt := truncate(h.Sum(nil)) % mod
+	fmtStr := fmt.Sprintf("%%0%dd", o.size)
+	return fmt.Sprintf(fmtStr, dt)
+}
+
+// truncate contains the DT function from the RFC; this is used to
+// deterministically select a sequence of 4 bytes from the HMAC
+// counter hash.
+func truncate(in []byte) int64 {
+	offset := int(in[len(in)-1] & 0xF)
+	p := in[offset : offset+4]
+	var binCode int32
+	binCode = int32((p[0] & 0x7f)) << 24
+	binCode += int32((p[1] & 0xff)) << 16
+	binCode += int32((p[2] & 0xff)) << 8
+	binCode += int32((p[3] & 0xff))
+	return int64(binCode) & 0x7FFFFFFF
+}
+
+// QR generates a byte slice containing the a QR code encoded as a
+// PNG with level Q error correction.
+func (o *OATH) QR(t Type, label string) ([]byte, error) {
+	u := o.URL(t, label)
+	code, err := qr.Encode(u, qr.Q)
+	if err != nil {
+		return nil, err
+	}
+	return code.PNG(), nil
+}

twofactor/oath_internal_test.go

@@ -0,0 +1,27 @@
+package twofactor
+
+import (
+	"testing"
+)
+
+var sha1Hmac = []byte{
+	0x1f, 0x86, 0x98, 0x69, 0x0e,
+	0x02, 0xca, 0x16, 0x61, 0x85,
+	0x50, 0xef, 0x7f, 0x19, 0xda,
+	0x8e, 0x94, 0x5b, 0x55, 0x5a,
+}
+
+var truncExpect int64 = 0x50ef7f19
+
+// This test runs through the truncation example given in the RFC.
+func TestTruncate(t *testing.T) {
+	if result := truncate(sha1Hmac); result != truncExpect {
+		t.Fatalf("hotp: expected truncate -> %d, saw %d\n",
+			truncExpect, result)
+	}
+
+	sha1Hmac[19]++
+	if result := truncate(sha1Hmac); result == truncExpect {
+		t.Fatal("hotp: expected truncation to fail")
+	}
+}

twofactor/otp.go

@@ -0,0 +1,86 @@
+package twofactor
+
+import (
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"hash"
+	"net/url"
+)
+
+type Type uint
+
+const (
+	OATH_HOTP = iota
+	OATH_TOTP
+)
+
+// PRNG is an io.Reader that provides a cryptographically secure
+// random byte stream.
+var PRNG = rand.Reader
+
+var (
+	ErrInvalidURL  = errors.New("twofactor: invalid URL")
+	ErrInvalidAlgo = errors.New("twofactor: invalid algorithm")
+)
+
+// OTP represents a one-time password token -- whether a
+// software taken (as in the case of Google Authenticator) or a
+// hardware token (as in the case of a YubiKey).
+type OTP interface {
+	// Returns the current counter value; the meaning of the
+	// returned value is algorithm-specific.
+	Counter() uint64
+
+	// Set the counter to a specific value.
+	SetCounter(uint64)
+
+	// the secret key contained in the OTP
+	Key() []byte
+
+	// generate a new OTP
+	OTP() string
+
+	// the output size of the OTP
+	Size() int
+
+	// the hash function used by the OTP
+	Hash() func() hash.Hash
+
+	// Returns the type of this OTP.
+	Type() Type
+}
+
+func otpString(otp OTP) string {
+	var typeName string
+	switch otp.Type() {
+	case OATH_HOTP:
+		typeName = "OATH-HOTP"
+	case OATH_TOTP:
+		typeName = "OATH-TOTP"
+	default:
+		typeName = "UNKNOWN"
+	}
+	return fmt.Sprintf("%s, %d", typeName, otp.Size())
+}
+
+// FromURL constructs a new OTP token from a URL string.
+func FromURL(otpURL string) (OTP, string, error) {
+	u, err := url.Parse(otpURL)
+	if err != nil {
+		return nil, "", err
+	}
+
+	if u.Scheme != "otpauth" {
+		return nil, "", ErrInvalidURL
+	}
+
+	switch u.Host {
+	case "totp":
+		return totpFromURL(u)
+	case "hotp":
+		return hotpFromURL(u)
+	default:
+		return nil, "", ErrInvalidURL
+	}
+}

twofactor/otp_internal_test.go

@@ -0,0 +1,126 @@
+package twofactor
+
+import (
+	"io"
+	"testing"
+)
+
+func TestHOTPString(t *testing.T) {
+	hotp := NewHOTP(nil, 0, 6)
+	hotpString := otpString(hotp)
+	if hotpString != "OATH-HOTP, 6" {
+		t.Fatal("twofactor: invalid OTP string")
+	}
+}
+
+// This test generates a new OTP, outputs the URL for that OTP,
+// and attempts to parse that URL. It verifies that the two OTPs
+// are the same, and that they produce the same output.
+func TestURL(t *testing.T) {
+	var ident = "testuser@foo"
+	otp := NewHOTP(testKey, 0, 6)
+	url := otp.URL("testuser@foo")
+	otp2, id, err := FromURL(url)
+	switch {
+	case err != nil:
+		t.Fatal("hotp: failed to parse HOTP URL\n")
+	case id != ident:
+		t.Logf("hotp: bad label\n")
+		t.Logf("\texpected: %s\n", ident)
+		t.Fatalf("\t  actual: %s\n", id)
+	case otp2.Counter() != otp.Counter():
+		t.Logf("hotp: OTP counters aren't synced\n")
+		t.Logf("\toriginal: %d\n", otp.Counter())
+		t.Fatalf("\t  second: %d\n", otp2.Counter())
+	}
+
+	code1 := otp.OTP()
+	code2 := otp2.OTP()
+	if code1 != code2 {
+		t.Logf("hotp: mismatched OTPs\n")
+		t.Logf("\texpected: %s\n", code1)
+		t.Fatalf("\t  actual: %s\n", code2)
+	}
+
+	// There's not much we can do test the QR code, except to
+	// ensure it doesn't fail.
+	_, err = otp.QR(ident)
+	if err != nil {
+		t.Fatalf("hotp: failed to generate QR code PNG (%v)\n", err)
+	}
+
+	// This should fail because the maximum size of an alphanumeric
+	// QR code with the lowest-level of error correction should
+	// max out at 4296 bytes. 8k may be a bit overkill... but it
+	// gets the job done. The value is read from the PRNG to
+	// increase the likelihood that the returned data is
+	// uncompressible.
+	var tooBigIdent = make([]byte, 8192)
+	_, err = io.ReadFull(PRNG, tooBigIdent)
+	if err != nil {
+		t.Fatalf("hotp: failed to read identity (%v)\n", err)
+	} else if _, err = otp.QR(string(tooBigIdent)); err == nil {
+		t.Fatal("hotp: QR code should fail to encode oversized URL")
+	}
+}
+
+// This test makes sure we can generate codes for padded and non-padded
+// entries.
+func TestPaddedURL(t *testing.T) {
+	var urlList = []string{
+		"otpauth://hotp/?secret=ME",
+		"otpauth://hotp/?secret=MEFR",
+		"otpauth://hotp/?secret=MFRGG",
+		"otpauth://hotp/?secret=MFRGGZA",
+		"otpauth://hotp/?secret=a6mryljlbufszudtjdt42nh5by=======",
+		"otpauth://hotp/?secret=a6mryljlbufszudtjdt42nh5by",
+		"otpauth://hotp/?secret=a6mryljlbufszudtjdt42nh5by%3D%3D%3D%3D%3D%3D%3D",
+	}
+	var codeList = []string{
+		"413198",
+		"770938",
+		"670717",
+		"402378",
+		"069864",
+		"069864",
+		"069864",
+	}
+
+	for i := range urlList {
+		if o, id, err := FromURL(urlList[i]); err != nil {
+			t.Log("hotp: URL should have parsed successfully (id=", id, ")")
+			t.Logf("\turl was: %s\n", urlList[i])
+			t.Fatalf("\t%s, %s\n", o.OTP(), id)
+		} else {
+			code2 := o.OTP()
+			if code2 != codeList[i] {
+				t.Logf("hotp: mismatched OTPs\n")
+				t.Logf("\texpected: %s\n", codeList[i])
+				t.Fatalf("\t  actual: %s\n", code2)
+			}
+		}
+	}
+}
+
+// This test attempts a variety of invalid urls against the parser
+// to ensure they fail.
+func TestBadURL(t *testing.T) {
+	var urlList = []string{
+		"http://google.com",
+		"",
+		"-",
+		"foo",
+		"otpauth:/foo/bar/baz",
+		"://",
+		"otpauth://hotp/?digits=",
+		"otpauth://hotp/?secret=MFRGGZDF&digits=ABCD",
+		"otpauth://hotp/?secret=MFRGGZDF&counter=ABCD",
+	}
+
+	for i := range urlList {
+		if _, _, err := FromURL(urlList[i]); err == nil {
+			t.Log("hotp: URL should not have parsed successfully")
+			t.Fatalf("\turl was: %s\n", urlList[i])
+		}
+	}
+}

twofactor/totp.go

@@ -0,0 +1,172 @@
+package twofactor
+
+import (
+	"crypto"
+	"crypto/sha1" // #nosec G505 - required by RFC
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/base32"
+	"hash"
+	"io"
+	"net/url"
+	"strconv"
+	"strings"
+
+	"github.com/benbjohnson/clock"
+)
+
+var timeSource = clock.New()
+
+// TOTP represents an RFC 6238 Time-based One-Time Password instance.
+type TOTP struct {
+	*OATH
+	step uint64
+}
+
+// NewTOTP takes a new key, a starting time, a step, the number of
+// digits of output (typically 6 or 8) and the hash algorithm to
+// use, and builds a new OTP.
+func NewTOTP(key []byte, start uint64, step uint64, digits int, algo crypto.Hash) *TOTP {
+	h := hashFromAlgo(algo)
+	if h == nil {
+		return nil
+	}
+
+	return &TOTP{
+		OATH: &OATH{
+			key:     key,
+			counter: start,
+			size:    digits,
+			hash:    h,
+			algo:    algo,
+		},
+		step: step,
+	}
+}
+
+// NewGoogleTOTP takes a secret as a base32-encoded string and
+// returns an appropriate Google Authenticator TOTP instance.
+func NewGoogleTOTP(secret string) (*TOTP, error) {
+	key, err := base32.StdEncoding.DecodeString(secret)
+	if err != nil {
+		return nil, err
+	}
+	return NewTOTP(key, 0, 30, 6, crypto.SHA1), nil
+}
+
+// NewTOTPSHA1 will build a new TOTP using SHA-1.
+func NewTOTPSHA1(key []byte, start uint64, step uint64, digits int) *TOTP {
+	return NewTOTP(key, start, step, digits, crypto.SHA1)
+}
+
+// Type returns OATH_TOTP.
+func (otp *TOTP) Type() Type {
+	return OATH_TOTP
+}
+
+func (otp *TOTP) otp(counter uint64) string {
+	return otp.OATH.OTP(counter)
+}
+
+// OTP returns the OTP for the current timestep.
+func (otp *TOTP) OTP() string {
+	return otp.otp(otp.OTPCounter())
+}
+
+// URL returns a TOTP URL (i.e. for putting in a QR code).
+func (otp *TOTP) URL(label string) string {
+	return otp.OATH.URL(otp.Type(), label)
+}
+
+// SetProvider sets up the provider component of the OTP URL.
+func (otp *TOTP) SetProvider(provider string) {
+	otp.provider = provider
+}
+
+func (otp *TOTP) otpCounter(t uint64) uint64 {
+	return (t - otp.counter) / otp.step
+}
+
+// OTPCounter returns the current time value for the OTP.
+func (otp *TOTP) OTPCounter() uint64 {
+	return otp.otpCounter(uint64(timeSource.Now().Unix() & 0x7FFFFFFF)) //#nosec G115 - masked out overflow bits
+}
+
+func hashFromAlgo(algo crypto.Hash) func() hash.Hash {
+	switch algo {
+	case crypto.SHA1:
+		return sha1.New
+	case crypto.SHA256:
+		return sha256.New
+	case crypto.SHA512:
+		return sha512.New
+	}
+	return nil
+}
+
+// GenerateGoogleTOTP produces a new TOTP token with the defaults expected by
+// Google Authenticator.
+func GenerateGoogleTOTP() *TOTP {
+	key := make([]byte, sha1.Size)
+	if _, err := io.ReadFull(PRNG, key); err != nil {
+		return nil
+	}
+	return NewTOTP(key, 0, 30, 6, crypto.SHA1)
+}
+
+func totpFromURL(u *url.URL) (*TOTP, string, error) {
+	label := u.Path[1:]
+	v := u.Query()
+
+	secret := strings.ToUpper(v.Get("secret"))
+	if secret == "" {
+		return nil, "", ErrInvalidURL
+	}
+
+	var algo = crypto.SHA1
+	if algorithm := v.Get("algorithm"); algorithm != "" {
+		switch {
+		case strings.EqualFold(algorithm, "SHA256"):
+			algo = crypto.SHA256
+		case strings.EqualFold(algorithm, "SHA512"):
+			algo = crypto.SHA512
+		case !strings.EqualFold(algorithm, "SHA1"):
+			return nil, "", ErrInvalidAlgo
+		}
+	}
+
+	var digits = 6
+	if sdigit := v.Get("digits"); sdigit != "" {
+		tmpDigits, err := strconv.ParseInt(sdigit, 10, 8)
+		if err != nil {
+			return nil, "", err
+		}
+		digits = int(tmpDigits)
+	}
+
+	var period uint64 = 30
+	if speriod := v.Get("period"); speriod != "" {
+		var err error
+		period, err = strconv.ParseUint(speriod, 10, 64)
+		if err != nil {
+			return nil, "", err
+		}
+	}
+
+	key, err := base32.StdEncoding.DecodeString(Pad(secret))
+	if err != nil {
+		// assume secret isn't base32 encoded
+		key = []byte(secret)
+	}
+	otp := NewTOTP(key, 0, period, digits, algo)
+	return otp, label, nil
+}
+
+// QR generates a new TOTP QR code.
+func (otp *TOTP) QR(label string) ([]byte, error) {
+	return otp.OATH.QR(otp.Type(), label)
+}
+
+func SetClock(c clock.Clock) {
+	timeSource = c
+}

twofactor/totp_internal_test.go

@@ -0,0 +1,85 @@
+package twofactor
+
+import (
+	"crypto"
+	"testing"
+	"time"
+
+	"github.com/benbjohnson/clock"
+)
+
+var rfcTotpKey = map[crypto.Hash][]byte{
+	crypto.SHA1:   []byte("12345678901234567890"),
+	crypto.SHA256: []byte("12345678901234567890123456789012"),
+	crypto.SHA512: []byte("1234567890123456789012345678901234567890123456789012345678901234"),
+}
+
+var rfcTotpStep uint64 = 30
+
+var rfcTotpTests = []struct {
+	Time uint64
+	Code string
+	T    uint64
+	Algo crypto.Hash
+}{
+	{59, "94287082", 1, crypto.SHA1},
+	{59, "46119246", 1, crypto.SHA256},
+	{59, "90693936", 1, crypto.SHA512},
+	{1111111109, "07081804", 37037036, crypto.SHA1},
+	{1111111109, "68084774", 37037036, crypto.SHA256},
+	{1111111109, "25091201", 37037036, crypto.SHA512},
+	{1111111111, "14050471", 37037037, crypto.SHA1},
+	{1111111111, "67062674", 37037037, crypto.SHA256},
+	{1111111111, "99943326", 37037037, crypto.SHA512},
+	{1234567890, "89005924", 41152263, crypto.SHA1},
+	{1234567890, "91819424", 41152263, crypto.SHA256},
+	{1234567890, "93441116", 41152263, crypto.SHA512},
+	{2000000000, "69279037", 66666666, crypto.SHA1},
+	{2000000000, "90698825", 66666666, crypto.SHA256},
+	{2000000000, "38618901", 66666666, crypto.SHA512},
+	{20000000000, "65353130", 666666666, crypto.SHA1},
+	{20000000000, "77737706", 666666666, crypto.SHA256},
+	{20000000000, "47863826", 666666666, crypto.SHA512},
+}
+
+func TestTotpRFC(t *testing.T) {
+	for _, tc := range rfcTotpTests {
+		otp := NewTOTP(rfcTotpKey[tc.Algo], 0, rfcTotpStep, 8, tc.Algo)
+		if otp.otpCounter(tc.Time) != tc.T {
+			t.Logf("twofactor: invalid TOTP (t=%d, h=%d)\n", tc.Time, tc.Algo)
+			t.Logf("\texpected: %d\n", tc.T)
+			t.Errorf("\t  actual: %d\n", otp.otpCounter(tc.Time))
+		}
+
+		if code := otp.otp(otp.otpCounter(tc.Time)); code != tc.Code {
+			t.Logf("twofactor: invalid TOTP (t=%d, h=%d)\n", tc.Time, tc.Algo)
+			t.Logf("\texpected: %s\n", tc.Code)
+			t.Errorf("\t  actual: %s\n", code)
+		}
+	}
+}
+
+func TestTOTPTime(t *testing.T) {
+	otp := GenerateGoogleTOTP()
+
+	testClock := clock.NewMock()
+	testClock.Add(2 * time.Minute)
+	SetClock(testClock)
+
+	code := otp.OTP()
+
+	testClock.Add(-1 * time.Minute)
+	if newCode := otp.OTP(); newCode == code {
+		t.Errorf("twofactor: TOTP: previous code %s shouldn't match code %s", newCode, code)
+	}
+
+	testClock.Add(2 * time.Minute)
+	if newCode := otp.OTP(); newCode == code {
+		t.Errorf("twofactor: TOTP: future code %s shouldn't match code %s", newCode, code)
+	}
+
+	testClock.Add(-1 * time.Minute)
+	if newCode := otp.OTP(); newCode != code {
+		t.Errorf("twofactor: TOTP: current code %s shouldn't match code %s", newCode, code)
+	}
+}

twofactor/util.go

@@ -0,0 +1,16 @@
+package twofactor
+
+import (
+	"strings"
+)
+
+// Pad calculates the number of '='s to add to our encoded string
+// to make base32.StdEncoding.DecodeString happy.
+func Pad(s string) string {
+	if !strings.HasSuffix(s, "=") && len(s)%8 != 0 {
+		for len(s)%8 != 0 {
+			s += "="
+		}
+	}
+	return s
+}

twofactor/util_test.go

@@ -0,0 +1,51 @@
+package twofactor_test
+
+import (
+	"encoding/base32"
+	"math/rand"
+	"strings"
+	"testing"
+
+	"git.wntrmute.dev/kyle/goutils/twofactor"
+)
+
+const letters = "1234567890!@#$%^&*()abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+func randString() string {
+	b := make([]byte, rand.Intn(len(letters)))
+	for i := range b {
+		b[i] = letters[rand.Intn(len(letters))]
+	}
+	return base32.StdEncoding.EncodeToString(b)
+}
+
+func TestPadding(t *testing.T) {
+	for range 300 {
+		b := randString()
+		origEncoding := b
+		modEncoding := strings.ReplaceAll(b, "=", "")
+		str, err := base32.StdEncoding.DecodeString(origEncoding)
+		if err != nil {
+			t.Fatal("Can't decode: ", b)
+		}
+
+		paddedEncoding := twofactor.Pad(modEncoding)
+		if origEncoding != paddedEncoding {
+			t.Log("Padding failed:")
+			t.Logf("Expected: '%s'", origEncoding)
+			t.Fatalf("Got: '%s'", paddedEncoding)
+		} else {
+			var mstr []byte
+			mstr, err = base32.StdEncoding.DecodeString(paddedEncoding)
+			if err != nil {
+				t.Fatal("Can't decode: ", paddedEncoding)
+			}
+
+			if string(mstr) != string(str) {
+				t.Log("Re-padding failed:")
+				t.Logf("Expected: '%s'", str)
+				t.Fatalf("Got: '%s'", mstr)
+			}
+		}
+	}
+}