Update CHANGELOG for v1.13.3.

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.

.circleci/config.yml

@@ -64,4 +64,4 @@ workflows:
   testbuild:
     jobs:
       - testbuild
-#      - lint
+      - lint

.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

@@ -12,12 +12,31 @@
 
 version: "2"
 
+output:
+  sort-order:
+    - file
+    - linter
+    - severity
+
 issues:
   # Maximum count of issues with the same text.
   # Set to 0 to disable.
   # Default: 3
   max-same-issues: 50
 
+  # Exclude some lints for CLI programs under cmd/ (package main).
+  # The project allows fmt.Print* in command-line tools; keep forbidigo for libraries.
+  exclude-rules:
+    - path: ^cmd/
+      linters:
+        - forbidigo
+    - path: cmd/.*
+      linters:
+        - forbidigo
+    - path: .*/cmd/.*
+      linters:
+        - forbidigo
+
 formatters:
   enable:
     - goimports # checks if the code and import statements are formatted according to the 'goimports' command
@@ -73,7 +92,6 @@ linters:
     - godoclint # checks Golang's documentation practice
     - godot # checks if comments end in a period
     - gomoddirectives # manages the use of 'replace', 'retract', and 'excludes' directives in go.mod
-    - goprintffuncname # checks that printf-like functions are named with f at the end
     - gosec # inspects source code for security problems
     - govet # reports suspicious constructs, such as Printf calls whose arguments do not align with the format string
     - iface # checks the incorrect use of interfaces, helping developers avoid interface pollution
@@ -230,6 +248,10 @@ linters:
       check-type-assertions: true
       exclude-functions:
         - (*git.wntrmute.dev/kyle/goutils/sbuf.Buffer).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
 
     exhaustive:
       # Program elements to check for exhaustiveness.
@@ -321,6 +343,12 @@ linters:
         # https://github.com/godoc-lint/godoc-lint?tab=readme-ov-file#no-unused-link
         - no-unused-link
 
+    gosec:
+      excludes:
+        - G104 # handled by errcheck
+        - G301
+        - G306
+
     govet:
       # Enable all analyzers.
       # Default: false
@@ -356,6 +384,15 @@ linters:
         - os.WriteFile
         - prometheus.ExponentialBuckets.*
         - prometheus.LinearBuckets
+      ignored-numbers:
+        - 1
+        - 2
+        - 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.
@@ -424,6 +461,10 @@ linters:
         # Omit embedded fields from selector expression.
         # https://staticcheck.dev/docs/checks/#QF1008
         - -QF1008
+        # We often explicitly enable old/deprecated ciphers for research.
+        - -SA1019
+        # Covered by revive.
+        - -ST1003
 
     usetesting:
       # Enable/disable `os.TempDir()` detections.
@@ -442,6 +483,8 @@ 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'
@@ -452,6 +495,8 @@ linters:
         linters: [ testableexamples ]
       - path: 'main.go'
         linters: [ forbidigo, mnd, reassign ]
+      - path: 'cmd/cruntar/main.go'
+        linters: [ unparam ]
       - source: 'TODO'
         linters: [ godot ]
       - text: 'should have a package comment'

.goreleaser.yaml

@@ -0,0 +1,453 @@
+# 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]
+    # this name template makes the OS and Arch compatible with the results of `uname`.
+    name_template: >-
+      {{ .ProjectName }}_
+      {{- title .Os }}_
+      {{- if eq .Arch "amd64" }}x86_64
+      {{- else if eq .Arch "386" }}i386
+      {{- else }}{{ .Arch }}{{ end }}
+      {{- if .Arm }}v{{ .Arm }}{{ end }}
+    # use zip for windows archives
+    format_overrides:
+      - goos: windows
+        formats: [zip]
+
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"
+
+gitea_urls:
+  api: https://git.wntrmute.dev/api/v1
+  download: https://git.wntrmute.dev
+  # set to true if you use a self-signed certificate
+  skip_tls_verify: false
+
+release:
+  footer: >-
+
+    ---
+
+    Released by [GoReleaser](https://github.com/goreleaser/goreleaser).

CHANGELOG

@@ -1,5 +1,81 @@
 CHANGELOG
 
+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
+- cmd: complete linting fixes across programs; no functional changes.
+
 v1.11.0 - 2025-11-15
 
 Added

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 = 5 * time.Millisecond
+const decay = time.Second
 const maxDuration = 10 * time.Millisecond
 const interval = time.Millisecond
 

cache/lru/lru_internal_test.go

@@ -1,87 +1,87 @@
 package lru
 
 import (
-    "testing"
-    "time"
+	"testing"
+	"time"
 
-    "github.com/benbjohnson/clock"
+	"github.com/benbjohnson/clock"
 )
 
 // These tests mirror the MRU-style behavior present in this LRU package
 // implementation (eviction removes the most-recently-used entry).
 func TestBasicCacheEviction(t *testing.T) {
-    mock := clock.NewMock()
-    c := NewStringKeyCache[int](2)
-    c.clock = mock
+	mock := clock.NewMock()
+	c := NewStringKeyCache[int](2)
+	c.clock = mock
 
-    if err := c.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    if c.Len() != 0 {
-        t.Fatal("cache should have size 0")
-    }
+	if c.Len() != 0 {
+		t.Fatal("cache should have size 0")
+	}
 
-    c.evict()
-    if err := c.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	c.evict()
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    c.Store("raven", 1)
-    if err := c.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	c.Store("raven", 1)
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    if len(c.store) != 1 {
-        t.Fatalf("store should have length=1, have length=%d", len(c.store))
-    }
+	if len(c.store) != 1 {
+		t.Fatalf("store should have length=1, have length=%d", len(c.store))
+	}
 
-    mock.Add(time.Second)
-    c.Store("owl", 2)
-    if err := c.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	mock.Add(time.Second)
+	c.Store("owl", 2)
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    if len(c.store) != 2 {
-        t.Fatalf("store should have length=2, have length=%d", len(c.store))
-    }
+	if len(c.store) != 2 {
+		t.Fatalf("store should have length=2, have length=%d", len(c.store))
+	}
 
-    mock.Add(time.Second)
-    c.Store("goat", 3)
-    if err := c.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	mock.Add(time.Second)
+	c.Store("goat", 3)
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    if len(c.store) != 2 {
-        t.Fatalf("store should have length=2, have length=%d", len(c.store))
-    }
+	if len(c.store) != 2 {
+		t.Fatalf("store should have length=2, have length=%d", len(c.store))
+	}
 
-    // Since this implementation evicts the most-recently-used item, inserting
-    // "goat" when full evicts "owl" (the most recent at that time).
-    mock.Add(time.Second)
-    if _, ok := c.Get("owl"); ok {
-        t.Fatal("store should not have an entry for owl (MRU-evicted)")
-    }
-    if err := c.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	// Since this implementation evicts the most-recently-used item, inserting
+	// "goat" when full evicts "owl" (the most recent at that time).
+	mock.Add(time.Second)
+	if _, ok := c.Get("owl"); ok {
+		t.Fatal("store should not have an entry for owl (MRU-evicted)")
+	}
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    mock.Add(time.Second)
-    c.Store("elk", 4)
-    if err := c.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	mock.Add(time.Second)
+	c.Store("elk", 4)
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    if !c.Has("elk") {
-        t.Fatal("store should contain an entry for 'elk'")
-    }
+	if !c.Has("elk") {
+		t.Fatal("store should contain an entry for 'elk'")
+	}
 
-    // Before storing elk, keys were: raven (older), goat (newer). Evict MRU -> goat.
-    if !c.Has("raven") {
-        t.Fatal("store should contain an entry for 'raven'")
-    }
+	// Before storing elk, keys were: raven (older), goat (newer). Evict MRU -> goat.
+	if !c.Has("raven") {
+		t.Fatal("store should contain an entry for 'raven'")
+	}
 
-    if c.Has("goat") {
-        t.Fatal("store should not contain an entry for 'goat'")
-    }
+	if c.Has("goat") {
+		t.Fatal("store should not contain an entry for 'goat'")
+	}
 }

cache/lru/timestamps_internal_test.go

@@ -1,50 +1,50 @@
 package lru
 
 import (
-    "testing"
-    "time"
+	"testing"
+	"time"
 
-    "github.com/benbjohnson/clock"
+	"github.com/benbjohnson/clock"
 )
 
 // These tests validate timestamps ordering semantics for the LRU package.
 // Note: The LRU timestamps are sorted with most-recent-first (descending by t).
 func TestTimestamps(t *testing.T) {
-    ts := newTimestamps[string](3)
-    mock := clock.NewMock()
+	ts := newTimestamps[string](3)
+	mock := clock.NewMock()
 
-    // raven
-    ts.Update("raven", mock.Now().UnixNano())
+	// raven
+	ts.Update("raven", mock.Now().UnixNano())
 
-    // raven, owl
-    mock.Add(time.Millisecond)
-    ts.Update("owl", mock.Now().UnixNano())
+	// raven, owl
+	mock.Add(time.Millisecond)
+	ts.Update("owl", mock.Now().UnixNano())
 
-    // raven, owl, goat
-    mock.Add(time.Second)
-    ts.Update("goat", mock.Now().UnixNano())
+	// raven, owl, goat
+	mock.Add(time.Second)
+	ts.Update("goat", mock.Now().UnixNano())
 
-    if err := ts.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	if err := ts.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    // make owl the most recent
-    mock.Add(time.Millisecond)
-    ts.Update("owl", mock.Now().UnixNano())
-    if err := ts.ConsistencyCheck(); err != nil {
-        t.Fatal(err)
-    }
+	// make owl the most recent
+	mock.Add(time.Millisecond)
+	ts.Update("owl", mock.Now().UnixNano())
+	if err := ts.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
-    // For LRU timestamps: most recent first. Expected order: owl, goat, raven.
-    if ts.K(0) != "owl" {
-        t.Fatalf("first key should be owl, have %s", ts.K(0))
-    }
+	// For LRU timestamps: most recent first. Expected order: owl, goat, raven.
+	if ts.K(0) != "owl" {
+		t.Fatalf("first key should be owl, have %s", ts.K(0))
+	}
 
-    if ts.K(1) != "goat" {
-        t.Fatalf("second key should be goat, have %s", ts.K(1))
-    }
+	if ts.K(1) != "goat" {
+		t.Fatalf("second key should be goat, have %s", ts.K(1))
+	}
 
-    if ts.K(2) != "raven" {
-        t.Fatalf("third key should be raven, have %s", ts.K(2))
-    }
+	if ts.K(2) != "raven" {
+		t.Fatalf("third key should be raven, have %s", ts.K(2))
+	}
 }

cache/mru/mru_internal_test.go

@@ -8,9 +8,9 @@ import (
 )
 
 func TestBasicCacheEviction(t *testing.T) {
-    mock := clock.NewMock()
-    c := NewStringKeyCache[int](2)
-    c.clock = mock
+	mock := clock.NewMock()
+	c := NewStringKeyCache[int](2)
+	c.clock = mock
 
 	if err := c.ConsistencyCheck(); err != nil {
 		t.Fatal(err)
@@ -55,18 +55,18 @@ func TestBasicCacheEviction(t *testing.T) {
 	}
 
 	mock.Add(time.Second)
- v, ok := c.Get("owl")
- if !ok {
-     t.Fatal("store should have an entry for owl")
- }
- if err := c.ConsistencyCheck(); err != nil {
-     t.Fatal(err)
- }
+	v, ok := c.Get("owl")
+	if !ok {
+		t.Fatal("store should have an entry for owl")
+	}
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
- itm := v
- if err := c.ConsistencyCheck(); err != nil {
-     t.Fatal(err)
- }
+	itm := v
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
 
 	if itm != 2 {
 		t.Fatalf("stored item should be 2, have %d", itm)

cache/mru/timestamps_internal_test.go

@@ -8,8 +8,8 @@ import (
 )
 
 func TestTimestamps(t *testing.T) {
-    ts := newTimestamps[string](3)
-    mock := clock.NewMock()
+	ts := newTimestamps[string](3)
+	mock := clock.NewMock()
 
 	// raven
 	ts.Update("raven", mock.Now().UnixNano())

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/fetch.go

@@ -0,0 +1,175 @@
+package certlib
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"os"
+
+	"git.wntrmute.dev/kyle/goutils/certlib/hosts"
+	"git.wntrmute.dev/kyle/goutils/fileutil"
+	"git.wntrmute.dev/kyle/goutils/lib"
+)
+
+// FetcherOpts are options for fetching certificates. They are only applicable to ServerFetcher.
+type FetcherOpts struct {
+	SkipVerify bool
+	Roots      *x509.CertPool
+}
+
+// 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, lib.Itoa(sf.port, -1)))
+}
+
+func (sf *ServerFetcher) GetChain() ([]*x509.Certificate, error) {
+	config := &tls.Config{
+		InsecureSkipVerify: sf.insecure, // #nosec G402 - no shit sherlock
+		RootCAs:            sf.roots,
+	}
+
+	dialer := &tls.Dialer{
+		Config: config,
+	}
+
+	hostSpec := net.JoinHostPort(sf.host, lib.Itoa(sf.port, -1))
+
+	netConn, err := dialer.DialContext(context.Background(), "tcp", hostSpec)
+	if err != nil {
+		return nil, fmt.Errorf("dialing server: %w", err)
+	}
+
+	conn, ok := netConn.(*tls.Conn)
+	if !ok {
+		return nil, errors.New("connection is not TLS")
+	}
+	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 ParseCertificatesPEM(certData)
+	}
+
+	certs, err := 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.
+func GetCertificateChain(spec string, opts *FetcherOpts) ([]*x509.Certificate, error) {
+	if fileutil.FileDoesExist(spec) {
+		return NewFileFetcher(spec).GetChain()
+	}
+
+	fetcher, err := ParseServer(spec)
+	if err != nil {
+		return nil, err
+	}
+
+	if opts != nil {
+		fetcher.insecure = opts.SkipVerify
+		fetcher.roots = opts.Roots
+	}
+
+	return fetcher.GetChain()
+}
+
+// GetCertificate fetches the first certificate from a certificate chain.
+func GetCertificate(spec string, opts *FetcherOpts) (*x509.Certificate, error) {
+	certs, err := GetCertificateChain(spec, opts)
+	if err != nil {
+		return nil, err
+	}
+
+	return certs[0], nil
+}

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 == "" {
@@ -458,8 +497,6 @@ func GetKeyDERFromPEM(in []byte, password []byte) ([]byte, error) {
 	}
 	if procType, ok := keyDER.Headers["Proc-Type"]; ok && strings.Contains(procType, "ENCRYPTED") {
 		if password != nil {
-			// nolintlint requires rationale:
-			//nolint:staticcheck // legacy RFC1423 PEM encryption supported for backward compatibility when caller supplies a password
 			return x509.DecryptPEMBlock(keyDER, password)
 		}
 		return nil, certerr.DecodeError(certerr.ErrorSourcePrivateKey, certerr.ErrEncryptedPrivateKey)

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)
+		}
+	}
+}

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

@@ -1,14 +1,15 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"crypto/x509"
-	"flag"
 	"errors"
+	"flag"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
+	"strings"
 	"time"
 
 	"git.wntrmute.dev/kyle/goutils/certlib"
@@ -23,6 +24,13 @@ var (
 	verbose  bool
 )
 
+var (
+	strOK      = "OK"
+	strExpired = "EXPIRED"
+	strRevoked = "REVOKED"
+	strUnknown = "UNKNOWN"
+)
+
 func main() {
 	flag.BoolVar(&hardfail, "hardfail", false, "treat revocation check failures as fatal")
 	flag.DurationVar(&timeout, "timeout", 10*time.Second, "network timeout for OCSP/CRL fetches and TLS site connects")
@@ -42,16 +50,16 @@ func main() {
 	for _, target := range flag.Args() {
 		status, err := processTarget(target)
 		switch status {
-		case "OK":
-			fmt.Printf("%s: OK\n", target)
-		case "EXPIRED":
-			fmt.Printf("%s: EXPIRED: %v\n", target, err)
+		case strOK:
+			fmt.Printf("%s: %s\n", target, strOK)
+		case strExpired:
+			fmt.Printf("%s: %s: %v\n", target, strExpired, err)
 			exitCode = 1
-		case "REVOKED":
-			fmt.Printf("%s: REVOKED\n", target)
+		case strRevoked:
+			fmt.Printf("%s: %s\n", target, strRevoked)
 			exitCode = 1
-		case "UNKNOWN":
-			fmt.Printf("%s: UNKNOWN: %v\n", target, err)
+		case strUnknown:
+			fmt.Printf("%s: %s: %v\n", target, strUnknown, err)
 			if hardfail {
 				// In hardfail, treat unknown as failure
 				exitCode = 1
@@ -67,74 +75,77 @@ func processTarget(target string) (string, error) {
 		return checkFile(target)
 	}
 
-	// Not a file; treat as site
 	return checkSite(target)
 }
 
 func checkFile(path string) (string, error) {
-	in, err := ioutil.ReadFile(path)
-	if err != nil {
-		return "UNKNOWN", err
+	// Prefer high-level helpers from certlib to load certificates from disk
+	if certs, err := certlib.LoadCertificates(path); err == nil && len(certs) > 0 {
+		// Evaluate the first certificate (leaf) by default
+		return evaluateCert(certs[0])
 	}
 
-	// Try PEM first; if that fails, try single DER cert
-	certs, err := certlib.ReadCertificates(in)
-	if err != nil || len(certs) == 0 {
-		cert, _, derr := certlib.ReadCertificate(in)
-		if derr != nil || cert == nil {
-			if err == nil {
-				err = derr
-			}
-			return "UNKNOWN", err
-		}
-		return evaluateCert(cert)
+	cert, err := certlib.LoadCertificate(path)
+	if err != nil || cert == nil {
+		return strUnknown, err
 	}
-
-	// Evaluate the first certificate (leaf) by default
-	return evaluateCert(certs[0])
+	return evaluateCert(cert)
 }
 
 func checkSite(hostport string) (string, error) {
 	// Use certlib/hosts to parse host/port (supports https URLs and host:port)
 	target, err := hosts.ParseHost(hostport)
 	if err != nil {
-		return "UNKNOWN", err
+		return strUnknown, err
 	}
 
 	d := &net.Dialer{Timeout: timeout}
-	conn, err := tls.DialWithDialer(d, "tcp", target.String(), &tls.Config{InsecureSkipVerify: true, ServerName: target.Host})
+	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())
 	if err != nil {
-		return "UNKNOWN", err
+		return strUnknown, err
 	}
 	defer conn.Close()
 
-	state := conn.ConnectionState()
+	tconn, ok := conn.(*tls.Conn)
+	if !ok {
+		return strUnknown, errors.New("connection is not TLS")
+	}
+
+	state := tconn.ConnectionState()
 	if len(state.PeerCertificates) == 0 {
-		return "UNKNOWN", errors.New("no peer certificates presented")
+		return strUnknown, errors.New("no peer certificates presented")
 	}
 	return evaluateCert(state.PeerCertificates[0])
 }
 
 func evaluateCert(cert *x509.Certificate) (string, error) {
-	// Expiry check
-	now := time.Now()
-	if !now.Before(cert.NotAfter) {
-		return "EXPIRED", fmt.Errorf("expired at %s", cert.NotAfter)
-	}
-	if !now.After(cert.NotBefore) {
-		return "EXPIRED", fmt.Errorf("not valid until %s", cert.NotBefore)
-	}
-
-	// Revocation check using certlib/revoke
+	// Delegate validity and revocation checks to certlib/revoke helper.
+	// It returns revoked=true for both revoked and expired/not-yet-valid.
+	// Map those cases back to our statuses using the returned error text.
 	revoked, ok, err := revoke.VerifyCertificateError(cert)
 	if revoked {
-		// If revoked is true, ok will be true per implementation, err may describe why
-		return "REVOKED", err
+		if err != nil {
+			msg := err.Error()
+			if strings.Contains(msg, "expired") || strings.Contains(msg, "isn't valid until") ||
+				strings.Contains(msg, "not valid until") {
+				return strExpired, err
+			}
+		}
+		return strRevoked, err
 	}
 	if !ok {
 		// Revocation status could not be determined
-		return "UNKNOWN", err
+		return strUnknown, err
 	}
 
-	return "OK", nil
+	return strOK, nil
 }

cmd/certchain/main.go

@@ -1,11 +1,14 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"encoding/pem"
 	"flag"
 	"fmt"
+	"os"
 	"regexp"
+	"strings"
 
 	"git.wntrmute.dev/kyle/goutils/die"
 )
@@ -20,20 +23,26 @@ func main() {
 			server += ":443"
 		}
 
-		var chain string
-
-		conn, err := tls.Dial("tcp", server, nil)
+		d := &tls.Dialer{Config: &tls.Config{}} // #nosec G402
+		nc, err := d.DialContext(context.Background(), "tcp", server)
 		die.If(err)
+		conn, ok := nc.(*tls.Conn)
+		if !ok {
+			die.With("invalid TLS connection (not a *tls.Conn)")
+		}
+
+		defer conn.Close()
 
 		details := conn.ConnectionState()
+		var chain strings.Builder
 		for _, cert := range details.PeerCertificates {
 			p := pem.Block{
 				Type:  "CERTIFICATE",
 				Bytes: cert.Raw,
 			}
-			chain += string(pem.EncodeToMemory(&p))
+			chain.Write(pem.EncodeToMemory(&p))
 		}
 
-		fmt.Println(chain)
+		fmt.Fprintln(os.Stdout, chain.String())
 	}
 }

cmd/certdump/certdump.go

@@ -1,328 +0,0 @@
-package main
-
-import (
-	"bytes"
-	"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/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.Printf("\tBasic constraints: ")
-	if cert.BasicConstraintsValid {
-		fmt.Printf("valid")
-	} else {
-		fmt.Printf("invalid")
-	}
-
-	if cert.IsCA {
-		fmt.Printf(", is a CA certificate")
-		if !cert.BasicConstraintsValid {
-			fmt.Printf(" (basic constraint failure)")
-		}
-	} else {
-		fmt.Printf("is not a CA certificate")
-		if cert.KeyUsage&x509.KeyUsageKeyEncipherment != 0 {
-			fmt.Printf(" (key encipherment usage enabled!)")
-		}
-	}
-
-	if (cert.MaxPathLen == 0 && cert.MaxPathLenZero) || (cert.MaxPathLen > 0) {
-		fmt.Printf(", max path length %d", cert.MaxPathLen)
-	}
-
-	fmt.Printf("\n")
-}
-
-const oneTrueDateFormat = "2006-01-02T15:04:05-0700"
-
-var (
-	dateFormat string
-	showHash   bool // if true, print a SHA256 hash of the certificate's Raw field
-)
-
-func wrapPrint(text string, indent int) {
-	tabs := ""
-	for i := 0; i < indent; i++ {
-		tabs += "\t"
-	}
-
-	fmt.Printf(tabs+"%s\n", wrap(text, indent))
-}
-
-func displayCert(cert *x509.Certificate) {
-	fmt.Println("CERTIFICATE")
-	if showHash {
-		fmt.Println(wrap(fmt.Sprintf("SHA256: %x", sha256.Sum256(cert.Raw)), 0))
-	}
-	fmt.Println(wrap("Subject: "+displayName(cert.Subject), 0))
-	fmt.Println(wrap("Issuer: "+displayName(cert.Issuer), 0))
-	fmt.Printf("\tSignature algorithm: %s / %s\n", sigAlgoPK(cert.SignatureAlgorithm),
-		sigAlgoHash(cert.SignatureAlgorithm))
-	fmt.Println("Details:")
-	wrapPrint("Public key: "+certPublic(cert), 1)
-	fmt.Printf("\tSerial number: %s\n", cert.SerialNumber)
-
-	if len(cert.AuthorityKeyId) > 0 {
-		fmt.Printf("\t%s\n", wrap("AKI: "+dumpHex(cert.AuthorityKeyId), 1))
-	}
-	if len(cert.SubjectKeyId) > 0 {
-		fmt.Printf("\t%s\n", wrap("SKI: "+dumpHex(cert.SubjectKeyId), 1))
-	}
-
-	wrapPrint("Valid from: "+cert.NotBefore.Format(dateFormat), 1)
-	fmt.Printf("\t     until: %s\n", cert.NotAfter.Format(dateFormat))
-	fmt.Printf("\tKey usages: %s\n", keyUsages(cert.KeyUsage))
-
-	if len(cert.ExtKeyUsage) > 0 {
-		fmt.Printf("\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)
-	conn, err := tls.Dial("tcp", ci.Addr, permissiveConfig())
-	if err != nil {
-		lib.Warn(err, "couldn't connect to %s", ci.Addr)
-		return
-	}
-	defer conn.Close()
-
-	state := conn.ConnectionState()
-	conn.Close()
-
-	conn, err = tls.Dial("tcp", ci.Addr, verifyConfig(ci.Host))
-	if err == nil {
-		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.Println("TLS chain verified successfully.")
-		for i := range state.VerifiedChains {
-			fmt.Printf("--- Verified certificate chain %d ---\n", i+1)
-			for j := range state.VerifiedChains[i] {
-				displayCert(state.VerifiedChains[i][j])
-			}
-		}
-	}
-}
-
-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.Parse()
-
-	if flag.NArg() == 0 || (flag.NArg() == 1 && flag.Arg(0) == "-") {
-		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.Replace(certs, []byte(`\n`), []byte{0xa}, -1)
-		certs = bytes.Trim(certs, `"`)
-		displayAllCerts(certs, leafOnly)
-	} else {
-		for _, filename := range flag.Args() {
-			fmt.Printf("--%s ---\n", filename)
-			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
-				}
-
-				displayAllCerts(in, leafOnly)
-			}
-		}
-	}
-}

cmd/certdump/main.go

@@ -0,0 +1,376 @@
+//lint:file-ignore SA1019 allow strict compatibility for old certs
+package main
+
+import (
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"flag"
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+
+	"github.com/kr/text"
+
+	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/lib"
+)
+
+// 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 {
+	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)
+}
+
+const oneTrueDateFormat = "2006-01-02T15:04:05-0700"
+
+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(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 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.Parse()
+
+	opts := &certlib.FetcherOpts{
+		SkipVerify: true,
+		Roots:      nil,
+	}
+
+	for _, filename := range flag.Args() {
+		fmt.Fprintf(os.Stdout, "--%s ---%s", filename, "\n")
+		certs, err := certlib.GetCertificateChain(filename, opts)
+		if err != nil {
+			_, _ = lib.Warn(err, "couldn't read certificate")
+			continue
+		}
+
+		if leafOnly {
+			displayCert(certs[0])
+			continue
+		}
+
+		for i := range certs {
+			displayCert(certs[i])
+		}
+	}
+}

cmd/certdump/util.go

@@ -1,176 +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,")
-
-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",
-}
-
-func pubKeyAlgo(a x509.PublicKeyAlgorithm) string {
-	switch a {
-	case x509.RSA:
-		return "RSA"
-	case x509.ECDSA:
-		return "ECDSA"
-	case x509.DSA:
-		return "DSA"
-	default:
-		return "unknown public key algorithm"
-	}
-}
-
-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.ECDSAWithSHA1, x509.ECDSAWithSHA256, x509.ECDSAWithSHA384, x509.ECDSAWithSHA512:
-		return "ECDSA"
-	case x509.DSAWithSHA1, x509.DSAWithSHA256:
-		return "DSA"
-	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 "SHA256"
-	case x509.SHA384WithRSA, x509.ECDSAWithSHA384:
-		return "SHA384"
-	case x509.SHA512WithRSA, x509.ECDSAWithSHA512:
-		return "SHA512"
-	default:
-		return "unknown hash algorithm"
-	}
-}
-
-const maxLine = 78
-
-func makeIndent(n int) string {
-	s := "    "
-	for i := 0; i < n; i++ {
-		s += "        "
-	}
-	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
-	for i := range in {
-		s += fmt.Sprintf("%02X:", in[i])
-	}
-
-	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,
-	}
-}
-
-// verifyConfig returns a config that will verify the connection.
-func verifyConfig(hostname string) *tls.Config {
-	return &tls.Config{
-		ServerName: hostname,
-	}
-}
-
-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

@@ -5,7 +5,6 @@ import (
 	"crypto/x509/pkix"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strings"
 	"time"
@@ -54,7 +53,7 @@ func displayName(name pkix.Name) string {
 }
 
 func expires(cert *x509.Certificate) time.Duration {
-	return cert.NotAfter.Sub(time.Now())
+	return time.Until(cert.NotAfter)
 }
 
 func inDanger(cert *x509.Certificate) bool {
@@ -76,20 +75,17 @@ func checkCert(cert *x509.Certificate) {
 }
 
 func main() {
+	opts := &certlib.FetcherOpts{}
+
+	flag.BoolVar(&opts.SkipVerify, "k", false, "skip server verification")
 	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 := ioutil.ReadFile(file)
+		certs, err := certlib.GetCertificateChain(file, opts)
 		if err != nil {
-			lib.Warn(err, "failed to read file")
-			continue
-		}
-
-		certs, err := certlib.ParseCertificatesPEM(in)
-		if err != nil {
-			lib.Warn(err, "while parsing certificates")
+			_, _ = lib.Warn(err, "while parsing certificates")
 			continue
 		}
 

cmd/certser/main.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"crypto/x509"
+	"flag"
+	"fmt"
+	"strings"
+
+	"git.wntrmute.dev/kyle/goutils/certlib"
+	"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() {
+	opts := &certlib.FetcherOpts{}
+	displayAs := flag.String("d", "int", "display mode (int, hex, uhex)")
+	showExpiry := flag.Bool("e", false, "show expiry date")
+	flag.BoolVar(&opts.SkipVerify, "k", false, "skip server verification")
+	flag.Parse()
+
+	displayMode := parseDisplayMode(*displayAs)
+
+	for _, arg := range flag.Args() {
+		cert, err := certlib.GetCertificate(arg, opts)
+		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

@@ -4,13 +4,11 @@ import (
 	"crypto/x509"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"time"
 
 	"git.wntrmute.dev/kyle/goutils/certlib"
 	"git.wntrmute.dev/kyle/goutils/certlib/revoke"
-	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
@@ -30,83 +28,122 @@ func printRevocation(cert *x509.Certificate) {
 	}
 }
 
-func main() {
-	var caFile, intFile string
-	var forceIntermediateBundle, revexp, verbose bool
-	flag.StringVar(&caFile, "ca", "", "CA certificate `bundle`")
-	flag.StringVar(&intFile, "i", "", "intermediate `bundle`")
-	flag.BoolVar(&forceIntermediateBundle, "f", false,
+type appConfig struct {
+	caFile, intFile             string
+	forceIntermediateBundle     bool
+	revexp, skipVerify, verbose bool
+}
+
+func parseFlags() appConfig {
+	var cfg appConfig
+	flag.StringVar(&cfg.caFile, "ca", "", "CA certificate `bundle`")
+	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(&revexp, "r", false, "print revocation and expiry information")
-	flag.BoolVar(&verbose, "v", false, "verbose")
+	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")
 	flag.Parse()
+	return cfg
+}
 
-	var roots *x509.CertPool
-	if caFile != "" {
-		var err error
-		if verbose {
-			fmt.Println("[+] loading root certificates from", caFile)
-		}
-		roots, err = certlib.LoadPEMCertPool(caFile)
-		die.If(err)
+func loadRoots(caFile string, verbose bool) (*x509.CertPool, error) {
+	if caFile == "" {
+		return x509.SystemCertPool()
 	}
 
-	var ints *x509.CertPool
-	if intFile != "" {
-		var err error
-		if verbose {
-			fmt.Println("[+] loading intermediate certificates from", intFile)
-		}
-		ints, err = certlib.LoadPEMCertPool(caFile)
-		die.If(err)
-	} else {
-		ints = x509.NewCertPool()
-	}
-
-	if flag.NArg() != 1 {
-		fmt.Fprintf(os.Stderr, "Usage: %s [-ca bundle] [-i bundle] cert",
-			lib.ProgName())
-	}
-
-	fileData, err := ioutil.ReadFile(flag.Arg(0))
-	die.If(err)
-
-	chain, err := certlib.ParseCertificatesPEM(fileData)
-	die.If(err)
 	if verbose {
-		fmt.Printf("[+] %s has %d certificates\n", flag.Arg(0), len(chain))
+		fmt.Println("[+] loading root certificates from", caFile)
 	}
+	return certlib.LoadPEMCertPool(caFile)
+}
 
-	cert := chain[0]
-	if len(chain) > 1 {
-		if !forceIntermediateBundle {
-			for _, intermediate := range chain[1:] {
-				if verbose {
-					fmt.Printf("[+] adding intermediate with SKI %x\n", intermediate.SubjectKeyId)
-				}
+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)
+}
 
-				ints.AddCert(intermediate)
-			}
+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
+}
 
-	_, err = cert.Verify(opts)
+func run(cfg appConfig) error {
+	roots, err := loadRoots(cfg.caFile, cfg.verbose)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "Verification failed: %v\n", err)
-		os.Exit(1)
+		return err
 	}
 
-	if verbose {
+	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())
+	}
+
+	combinedPool, err := certlib.LoadFullCertPool(cfg.caFile, cfg.intFile)
+	if err != nil {
+		return fmt.Errorf("failed to build combined pool: %w", err)
+	}
+
+	opts := &certlib.FetcherOpts{
+		Roots:      combinedPool,
+		SkipVerify: cfg.skipVerify,
+	}
+
+	chain, err := certlib.GetCertificateChain(flag.Arg(0), opts)
+	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 revexp {
+	if cfg.revexp {
 		printRevocation(cert)
 	}
+	return nil
+}
+
+func main() {
+	cfg := parseFlags()
+	if err := run(cfg); err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
+	}
 }

cmd/clustersh/main.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"bufio"
+	"context"
+	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -56,7 +58,7 @@ var modes = ssh.TerminalModes{
 }
 
 func sshAgent() ssh.AuthMethod {
-	a, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
+	a, err := (&net.Dialer{}).DialContext(context.Background(), "unix", os.Getenv("SSH_AUTH_SOCK"))
 	if err == nil {
 		return ssh.PublicKeysCallback(agent.NewClient(a).Signers)
 	}
@@ -82,7 +84,7 @@ func scanner(host string, in io.Reader, out io.Writer) {
 	}
 }
 
-func logError(host string, err error, format string, args ...interface{}) {
+func logError(host string, err error, format string, args ...any) {
 	msg := fmt.Sprintf(format, args...)
 	log.Printf("[%s] FAILED: %s: %v\n", host, msg, err)
 }
@@ -93,7 +95,7 @@ func exec(wg *sync.WaitGroup, user, host string, commands []string) {
 	defer func() {
 		for i := len(shutdown) - 1; i >= 0; i-- {
 			err := shutdown[i]()
-			if err != nil && err != io.EOF {
+			if err != nil && !errors.Is(err, io.EOF) {
 				logError(host, err, "shutting down")
 			}
 		}
@@ -115,7 +117,7 @@ func exec(wg *sync.WaitGroup, user, host string, commands []string) {
 	}
 	shutdown = append(shutdown, session.Close)
 
-	if err := session.RequestPty("xterm", 80, 40, modes); err != nil {
+	if err = session.RequestPty("xterm", 80, 40, modes); err != nil {
 		session.Close()
 		logError(host, err, "request for pty failed")
 		return
@@ -150,7 +152,7 @@ func upload(wg *sync.WaitGroup, user, host, local, remote string) {
 	defer func() {
 		for i := len(shutdown) - 1; i >= 0; i-- {
 			err := shutdown[i]()
-			if err != nil && err != io.EOF {
+			if err != nil && !errors.Is(err, io.EOF) {
 				logError(host, err, "shutting down")
 			}
 		}
@@ -199,7 +201,7 @@ func upload(wg *sync.WaitGroup, user, host, local, remote string) {
 			fmt.Printf("[%s] wrote %d-byte chunk\n", host, n)
 		}
 
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		} else if err != nil {
 			logError(host, err, "reading chunk")
@@ -215,7 +217,7 @@ func download(wg *sync.WaitGroup, user, host, local, remote string) {
 	defer func() {
 		for i := len(shutdown) - 1; i >= 0; i-- {
 			err := shutdown[i]()
-			if err != nil && err != io.EOF {
+			if err != nil && !errors.Is(err, io.EOF) {
 				logError(host, err, "shutting down")
 			}
 		}
@@ -265,7 +267,7 @@ func download(wg *sync.WaitGroup, user, host, local, remote string) {
 			fmt.Printf("[%s] wrote %d-byte chunk\n", host, n)
 		}
 
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		} else if err != nil {
 			logError(host, err, "reading chunk")

cmd/cruntar/main.go

@@ -10,6 +10,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/fileutil"
@@ -26,7 +27,7 @@ func setupFile(hdr *tar.Header, file *os.File) error {
 		if verbose {
 			fmt.Printf("\tchmod %0#o\n", hdr.Mode)
 		}
-		err := file.Chmod(os.FileMode(hdr.Mode))
+		err := file.Chmod(os.FileMode(hdr.Mode & 0xFFFFFFFF)) // #nosec G115
 		if err != nil {
 			return err
 		}
@@ -48,73 +49,105 @@ func linkTarget(target, top string) string {
 		return target
 	}
 
-	return filepath.Clean(filepath.Join(target, top))
+	return filepath.Clean(filepath.Join(top, target))
+}
+
+// safeJoin joins base and elem and ensures the resulting path does not escape base.
+func safeJoin(base, elem string) (string, error) {
+	cleanBase := filepath.Clean(base)
+	joined := filepath.Clean(filepath.Join(cleanBase, elem))
+
+	absBase, err := filepath.Abs(cleanBase)
+	if err != nil {
+		return "", err
+	}
+	absJoined, err := filepath.Abs(joined)
+	if err != nil {
+		return "", err
+	}
+	rel, err := filepath.Rel(absBase, absJoined)
+	if err != nil {
+		return "", err
+	}
+	if rel == ".." || strings.HasPrefix(rel, ".."+string(os.PathSeparator)) {
+		return "", fmt.Errorf("path traversal detected: %s escapes %s", elem, base)
+	}
+	return joined, nil
+}
+
+func handleTypeReg(tfr *tar.Reader, hdr *tar.Header, filePath string) error {
+	file, err := os.Create(filePath)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	if _, err = io.Copy(file, tfr); err != nil {
+		return err
+	}
+	return setupFile(hdr, file)
+}
+
+func handleTypeLink(hdr *tar.Header, top, filePath string) error {
+	file, err := os.Create(filePath)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	srcPath, err := safeJoin(top, hdr.Linkname)
+	if err != nil {
+		return err
+	}
+	source, err := os.Open(srcPath)
+	if err != nil {
+		return err
+	}
+	defer source.Close()
+
+	if _, err = io.Copy(file, source); err != nil {
+		return err
+	}
+	return setupFile(hdr, file)
+}
+
+func handleTypeSymlink(hdr *tar.Header, top, filePath string) error {
+	if !fileutil.ValidateSymlink(hdr.Linkname, top) {
+		return fmt.Errorf("symlink %s is outside the top-level %s", hdr.Linkname, top)
+	}
+	path := linkTarget(hdr.Linkname, top)
+	if ok, err := filepath.Match(top+"/*", filepath.Clean(path)); !ok {
+		return fmt.Errorf("symlink %s isn't in %s", hdr.Linkname, top)
+	} else if err != nil {
+		return err
+	}
+	return os.Symlink(linkTarget(hdr.Linkname, top), filePath)
+}
+
+func handleTypeDir(hdr *tar.Header, filePath string) error {
+	return os.MkdirAll(filePath, os.FileMode(hdr.Mode&0xFFFFFFFF)) // #nosec G115
 }
 
 func processFile(tfr *tar.Reader, hdr *tar.Header, top string) error {
 	if verbose {
 		fmt.Println(hdr.Name)
 	}
-	filePath := filepath.Clean(filepath.Join(top, hdr.Name))
-	switch hdr.Typeflag {
-	case tar.TypeReg:
-		file, err := os.Create(filePath)
-		if err != nil {
-			return err
-		}
 
-		_, err = io.Copy(file, tfr)
-		if err != nil {
-			return err
-		}
-
-		err = setupFile(hdr, file)
-		if err != nil {
-			return err
-		}
-	case tar.TypeLink:
-		file, err := os.Create(filePath)
-		if err != nil {
-			return err
-		}
-
-		source, err := os.Open(hdr.Linkname)
-		if err != nil {
-			return err
-		}
-
-		_, err = io.Copy(file, source)
-		if err != nil {
-			return err
-		}
-
-		err = setupFile(hdr, file)
-		if err != nil {
-			return err
-		}
-	case tar.TypeSymlink:
-		if !fileutil.ValidateSymlink(hdr.Linkname, top) {
-			return fmt.Errorf("symlink %s is outside the top-level %s",
-				hdr.Linkname, top)
-		}
-		path := linkTarget(hdr.Linkname, top)
-		if ok, err := filepath.Match(top+"/*", filepath.Clean(path)); !ok {
-			return fmt.Errorf("symlink %s isn't in %s", hdr.Linkname, top)
-		} else if err != nil {
-			return err
-		}
-
-		err := os.Symlink(linkTarget(hdr.Linkname, top), filePath)
-		if err != nil {
-			return err
-		}
-	case tar.TypeDir:
-		err := os.MkdirAll(filePath, os.FileMode(hdr.Mode))
-		if err != nil {
-			return err
-		}
+	filePath, err := safeJoin(top, hdr.Name)
+	if err != nil {
+		return err
 	}
 
+	switch hdr.Typeflag {
+	case tar.TypeReg:
+		return handleTypeReg(tfr, hdr, filePath)
+	case tar.TypeLink:
+		return handleTypeLink(hdr, top, filePath)
+	case tar.TypeSymlink:
+		return handleTypeSymlink(hdr, top, filePath)
+	case tar.TypeDir:
+		return handleTypeDir(hdr, filePath)
+	}
 	return nil
 }
 
@@ -261,16 +294,16 @@ func main() {
 	die.If(err)
 
 	tfr := tar.NewReader(r)
+	var hdr *tar.Header
 	for {
-		hdr, err := tfr.Next()
-		if err == io.EOF {
+		hdr, err = tfr.Next()
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		die.If(err)
 
 		err = processFile(tfr, hdr, top)
 		die.If(err)
-
 	}
 
 	r.Close()

cmd/csrpubdump/main.go

@@ -7,9 +7,9 @@ import (
 	"encoding/pem"
 	"flag"
 	"fmt"
-	"io/ioutil"
-	"log"
+	"os"
 
+	"git.wntrmute.dev/kyle/goutils/certlib"
 	"git.wntrmute.dev/kyle/goutils/die"
 )
 
@@ -17,17 +17,10 @@ func main() {
 	flag.Parse()
 
 	for _, fileName := range flag.Args() {
-		in, err := ioutil.ReadFile(fileName)
+		in, err := os.ReadFile(fileName)
 		die.If(err)
 
-		if p, _ := pem.Decode(in); p != nil {
-			if p.Type != "CERTIFICATE REQUEST" {
-				log.Fatal("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)
@@ -48,8 +41,8 @@ func main() {
 			Bytes: out,
 		}
 
-		err = ioutil.WriteFile(fileName+".pub", pem.EncodeToMemory(p), 0644)
+		err = os.WriteFile(fileName+".pub", pem.EncodeToMemory(p), 0o644) // #nosec G306
 		die.If(err)
-		fmt.Printf("[+] wrote %s.\n", fileName+".pub")
+		fmt.Fprintf(os.Stdout, "[+] wrote %s.\n", fileName+".pub")
 	}
 }

cmd/data_sync/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"io"
@@ -152,7 +153,7 @@ func rsync(syncDir, target, excludeFile string, verboseRsync bool) error {
 		return err
 	}
 
-	cmd := exec.Command(path, args...)
+	cmd := exec.CommandContext(context.Background(), path, args...)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	return cmd.Run()
@@ -163,7 +164,6 @@ func init() {
 }
 
 func main() {
-
 	var logLevel, mountDir, syncDir, target string
 	var dryRun, quietMode, noSyslog, verboseRsync bool
 
@@ -219,7 +219,7 @@ func main() {
 	if excludeFile != "" {
 		defer func() {
 			log.Infof("removing exclude file %s", excludeFile)
-			if err := os.Remove(excludeFile); err != nil {
+			if rmErr := os.Remove(excludeFile); rmErr != nil {
 				log.Warningf("failed to remove temp file %s", excludeFile)
 			}
 		}()

cmd/diskimg/main.go

@@ -15,43 +15,41 @@ import (
 const defaultHashAlgorithm = "sha256"
 
 var (
-	hAlgo      string
+	hAlgo string
 	debug = dbg.New()
 )
 
-
-func openImage(imageFile string) (image *os.File, hash []byte, err error) {
-	image, err = os.Open(imageFile)
+func openImage(imageFile string) (*os.File, []byte, error) {
+	f, err := os.Open(imageFile)
 	if err != nil {
-		return
+		return nil, nil, err
 	}
 
-	hash, err = ahash.SumReader(hAlgo, image)
+	h, err := ahash.SumReader(hAlgo, f)
 	if err != nil {
-		return
+		return nil, nil, err
 	}
 
-	_, err = image.Seek(0, 0)
-	if err != nil {
-		return
+	if _, err = f.Seek(0, 0); err != nil {
+		return nil, nil, err
 	}
 
-	debug.Printf("%s  %x\n", imageFile, hash)
-	return
+	debug.Printf("%s  %x\n", imageFile, h)
+	return f, h, nil
 }
 
-func openDevice(devicePath string) (device *os.File, err error) {
+func openDevice(devicePath string) (*os.File, error) {
 	fi, err := os.Stat(devicePath)
 	if err != nil {
-		return
+		return nil, err
 	}
 
-	device, err = os.OpenFile(devicePath, os.O_RDWR|os.O_SYNC, fi.Mode())
+	device, err := os.OpenFile(devicePath, os.O_RDWR|os.O_SYNC, fi.Mode())
 	if err != nil {
-		return
+		return nil, err
 	}
 
-	return
+	return device, nil
 }
 
 func main() {
@@ -105,12 +103,12 @@ func main() {
 	die.If(err)
 
 	if !bytes.Equal(deviceHash, hash) {
-		fmt.Fprintln(os.Stderr, "Hash mismatch:")
-		fmt.Fprintf(os.Stderr, "\t%s: %s\n", imageFile, hash)
-		fmt.Fprintf(os.Stderr, "\t%s: %s\n", devicePath, deviceHash)
-		os.Exit(1)
+		buf := &bytes.Buffer{}
+		fmt.Fprintln(buf, "Hash mismatch:")
+		fmt.Fprintf(buf, "\t%s: %s\n", imageFile, hash)
+		fmt.Fprintf(buf, "\t%s: %s\n", devicePath, deviceHash)
+		die.With(buf.String())
 	}
 
 	debug.Println("OK")
-	os.Exit(0)
 }

cmd/dumpbytes/main.go

@@ -1,30 +1,33 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"fmt"
-	"git.wntrmute.dev/kyle/goutils/die"
 	"io"
 	"os"
+	"strings"
+
+	"git.wntrmute.dev/kyle/goutils/die"
 )
 
 func usage(w io.Writer, exc int) {
-	fmt.Fprintln(w, `usage: dumpbytes <file>`)
+	fmt.Fprintln(w, `usage: dumpbytes -n tabs <file>`)
 	os.Exit(exc)
 }
 
 func printBytes(buf []byte) {
 	fmt.Printf("\t")
-	for i := 0; i < len(buf); i++ {
+	for i := range buf {
 		fmt.Printf("0x%02x, ", buf[i])
 	}
 	fmt.Println()
 }
 
 func dumpFile(path string, indentLevel int) error {
-	indent := ""
-	for i := 0; i < indentLevel; i++ {
-		indent += "\t"
+	var indent strings.Builder
+	for range indentLevel {
+		indent.WriteByte('\t')
 	}
 
 	file, err := os.Open(path)
@@ -34,13 +37,14 @@ func dumpFile(path string, indentLevel int) error {
 
 	defer file.Close()
 
-	fmt.Printf("%svar buffer = []byte{\n", indent)
+	fmt.Printf("%svar buffer = []byte{\n", indent.String())
+	var n int
 	for {
 		buf := make([]byte, 8)
-		n, err := file.Read(buf)
-		if err == io.EOF {
+		n, err = file.Read(buf)
+		if errors.Is(err, io.EOF) {
 			if n > 0 {
-				fmt.Printf("%s", indent)
+				fmt.Printf("%s", indent.String())
 				printBytes(buf[:n])
 			}
 			break
@@ -50,11 +54,11 @@ func dumpFile(path string, indentLevel int) error {
 			return err
 		}
 
-		fmt.Printf("%s", indent)
+		fmt.Printf("%s", indent.String())
 		printBytes(buf[:n])
 	}
 
-	fmt.Printf("%s}\n", indent)
+	fmt.Printf("%s}\n", indent.String())
 	return nil
 }
 

cmd/eig/main.go

@@ -7,7 +7,7 @@ import (
 	"git.wntrmute.dev/kyle/goutils/die"
 )
 
-// size of a kilobit in bytes
+// size of a kilobit in bytes.
 const kilobit = 128
 const pageSize = 4096
 
@@ -26,10 +26,10 @@ func main() {
 		path = flag.Arg(0)
 	}
 
-	fillByte := uint8(*fill)
+	fillByte := uint8(*fill & 0xff) // #nosec G115 clearing out of bounds bits
 
 	buf := make([]byte, pageSize)
-	for i := 0; i < pageSize; i++ {
+	for i := range pageSize {
 		buf[i] = fillByte
 	}
 
@@ -40,7 +40,7 @@ func main() {
 	die.If(err)
 	defer file.Close()
 
-	for i := 0; i < pages; i++ {
+	for range pages {
 		_, err = file.Write(buf)
 		die.If(err)
 	}

cmd/fragment/main.go

@@ -72,15 +72,13 @@ func main() {
 
 	if end < start {
 		fmt.Fprintln(os.Stderr, "[!] end < start, swapping values")
-		tmp := end
-		end = start
-		start = tmp
+		start, end = end, start
 	}
 
 	var fmtStr string
 
 	if !*quiet {
-		maxLine := fmt.Sprintf("%d", len(lines))
+		maxLine := strconv.Itoa(len(lines))
 		fmtStr = fmt.Sprintf("%%0%dd: %%s", len(maxLine))
 	}
 
@@ -98,9 +96,9 @@ func main() {
 	fmtStr += "\n"
 	for i := start; !endFunc(i); i++ {
 		if *quiet {
-			fmt.Println(lines[i])
+			fmt.Fprintln(os.Stdout, lines[i])
 		} else {
-			fmt.Printf(fmtStr, i, lines[i])
+			fmt.Fprintf(os.Stdout, fmtStr, i, lines[i])
 		}
 	}
 }

cmd/host/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"log"
@@ -8,7 +9,8 @@ import (
 )
 
 func lookupHost(host string) error {
-	cname, err := net.LookupCNAME(host)
+	r := &net.Resolver{}
+	cname, err := r.LookupCNAME(context.Background(), host)
 	if err != nil {
 		return err
 	}
@@ -18,7 +20,7 @@ func lookupHost(host string) error {
 		host = cname
 	}
 
-	addrs, err := net.LookupHost(host)
+	addrs, err := r.LookupHost(context.Background(), host)
 	if err != nil {
 		return err
 	}

cmd/jlp/main.go

@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 
 	"git.wntrmute.dev/kyle/goutils/lib"
@@ -16,20 +16,20 @@ func prettify(file string, validateOnly bool) error {
 	var err error
 
 	if file == "-" {
-		in, err = ioutil.ReadAll(os.Stdin)
+		in, err = io.ReadAll(os.Stdin)
 	} else {
-		in, err = ioutil.ReadFile(file)
+		in, err = os.ReadFile(file)
 	}
 
 	if err != nil {
-		lib.Warn(err, "ReadFile")
+		_, _ = lib.Warn(err, "ReadFile")
 		return err
 	}
 
 	var buf = &bytes.Buffer{}
 	err = json.Indent(buf, in, "", "    ")
 	if err != nil {
-		lib.Warn(err, "%s", file)
+		_, _ = lib.Warn(err, "%s", file)
 		return err
 	}
 
@@ -40,11 +40,11 @@ func prettify(file string, validateOnly bool) error {
 	if file == "-" {
 		_, err = os.Stdout.Write(buf.Bytes())
 	} else {
-		err = ioutil.WriteFile(file, buf.Bytes(), 0644)
+		err = os.WriteFile(file, buf.Bytes(), 0o644)
 	}
 
 	if err != nil {
-		lib.Warn(err, "WriteFile")
+		_, _ = lib.Warn(err, "WriteFile")
 	}
 
 	return err
@@ -55,20 +55,20 @@ func compact(file string, validateOnly bool) error {
 	var err error
 
 	if file == "-" {
-		in, err = ioutil.ReadAll(os.Stdin)
+		in, err = io.ReadAll(os.Stdin)
 	} else {
-		in, err = ioutil.ReadFile(file)
+		in, err = os.ReadFile(file)
 	}
 
 	if err != nil {
-		lib.Warn(err, "ReadFile")
+		_, _ = lib.Warn(err, "ReadFile")
 		return err
 	}
 
 	var buf = &bytes.Buffer{}
 	err = json.Compact(buf, in)
 	if err != nil {
-		lib.Warn(err, "%s", file)
+		_, _ = lib.Warn(err, "%s", file)
 		return err
 	}
 
@@ -79,11 +79,11 @@ func compact(file string, validateOnly bool) error {
 	if file == "-" {
 		_, err = os.Stdout.Write(buf.Bytes())
 	} else {
-		err = ioutil.WriteFile(file, buf.Bytes(), 0644)
+		err = os.WriteFile(file, buf.Bytes(), 0o644)
 	}
 
 	if err != nil {
-		lib.Warn(err, "WriteFile")
+		_, _ = lib.Warn(err, "WriteFile")
 	}
 
 	return err
@@ -91,7 +91,7 @@ func compact(file string, validateOnly bool) error {
 
 func usage() {
 	progname := lib.ProgName()
-	fmt.Printf(`Usage: %s [-h] files...
+	fmt.Fprintf(os.Stdout, `Usage: %s [-h] files...
 	%s is used to lint and prettify (or compact) JSON files. The
 	files will be updated in-place.
 
@@ -100,7 +100,6 @@ func usage() {
 	-h	Print this help message.
 	-n	Don't prettify; only perform validation.
 `, progname, progname)
-
 }
 
 func init() {

cmd/kgz/README

@@ -11,7 +11,10 @@ based on whether the source filename ends in ".gz".
 
 Flags:
 	-l level	Compression level (0-9). Only meaninful when
-			compressing a file.
+			    compressing a file.
+    -u          Do not restrict the size during decompression. As
+                a safeguard against gzip bombs, the maximum size
+                allowed is 32 * the compressed file size.
 
 
 

cmd/kgz/main.go

@@ -1,68 +1,84 @@
 package main
 
 import (
-    "compress/flate"
-    "compress/gzip"
-    "flag"
-    "fmt"
-    "io"
-    "os"
-    "path/filepath"
-    "strings"
+	"compress/flate"
+	"compress/gzip"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
 )
 
 const gzipExt = ".gz"
 
 func compress(path, target string, level int) error {
- sourceFile, err := os.Open(path)
- if err != nil {
-     return fmt.Errorf("opening file for read: %w", err)
- }
+	sourceFile, err := os.Open(path)
+	if err != nil {
+		return fmt.Errorf("opening file for read: %w", err)
+	}
 	defer sourceFile.Close()
 
- destFile, err := os.Create(target)
- if err != nil {
-     return fmt.Errorf("opening file for write: %w", err)
- }
+	destFile, err := os.Create(target)
+	if err != nil {
+		return fmt.Errorf("opening file for write: %w", err)
+	}
 	defer destFile.Close()
 
- gzipCompressor, err := gzip.NewWriterLevel(destFile, level)
- if err != nil {
-     return fmt.Errorf("invalid compression level: %w", err)
- }
+	gzipCompressor, err := gzip.NewWriterLevel(destFile, level)
+	if err != nil {
+		return fmt.Errorf("invalid compression level: %w", err)
+	}
 	defer gzipCompressor.Close()
 
- _, err = io.Copy(gzipCompressor, sourceFile)
- if err != nil {
-     return fmt.Errorf("compressing file: %w", err)
- }
+	_, err = io.Copy(gzipCompressor, sourceFile)
+	if err != nil {
+		return fmt.Errorf("compressing file: %w", err)
+	}
 
 	return nil
 }
 
-func uncompress(path, target string) error {
- sourceFile, err := os.Open(path)
- if err != nil {
-     return fmt.Errorf("opening file for read: %w", err)
- }
+func uncompress(path, target string, unrestrict bool) error {
+	sourceFile, err := os.Open(path)
+	if err != nil {
+		return fmt.Errorf("opening file for read: %w", err)
+	}
 	defer sourceFile.Close()
 
- gzipUncompressor, err := gzip.NewReader(sourceFile)
- if err != nil {
-     return fmt.Errorf("reading gzip headers: %w", err)
- }
+	fi, err := sourceFile.Stat()
+	if err != nil {
+		return fmt.Errorf("reading file stats: %w", err)
+	}
+
+	maxDecompressionSize := fi.Size() * 32
+
+	gzipUncompressor, err := gzip.NewReader(sourceFile)
+	if err != nil {
+		return fmt.Errorf("reading gzip headers: %w", err)
+	}
 	defer gzipUncompressor.Close()
 
- destFile, err := os.Create(target)
- if err != nil {
-     return fmt.Errorf("opening file for write: %w", err)
- }
+	var reader io.Reader = &io.LimitedReader{
+		R: gzipUncompressor,
+		N: maxDecompressionSize,
+	}
+
+	if unrestrict {
+		reader = gzipUncompressor
+	}
+
+	destFile, err := os.Create(target)
+	if err != nil {
+		return fmt.Errorf("opening file for write: %w", err)
+	}
 	defer destFile.Close()
 
- _, err = io.Copy(destFile, gzipUncompressor)
- if err != nil {
-     return fmt.Errorf("uncompressing file: %w", err)
- }
+	_, err = io.Copy(destFile, reader)
+	if err != nil {
+		return fmt.Errorf("uncompressing file: %w", err)
+	}
 
 	return nil
 }
@@ -87,8 +103,8 @@ func isDir(path string) bool {
 	file, err := os.Open(path)
 	if err == nil {
 		defer file.Close()
-		stat, err := file.Stat()
-		if err != nil {
+		stat, err2 := file.Stat()
+		if err2 != nil {
 			return false
 		}
 
@@ -106,9 +122,9 @@ func pathForUncompressing(source, dest string) (string, error) {
 	}
 
 	source = filepath.Base(source)
- if !strings.HasSuffix(source, gzipExt) {
-        return "", fmt.Errorf("%s is a not gzip-compressed file", source)
-    }
+	if !strings.HasSuffix(source, gzipExt) {
+		return "", fmt.Errorf("%s is a not gzip-compressed file", source)
+	}
 	outFile := source[:len(source)-len(gzipExt)]
 	outFile = filepath.Join(dest, outFile)
 	return outFile, nil
@@ -120,9 +136,9 @@ func pathForCompressing(source, dest string) (string, error) {
 	}
 
 	source = filepath.Base(source)
- if strings.HasSuffix(source, gzipExt) {
-        return "", fmt.Errorf("%s is a gzip-compressed file", source)
-    }
+	if strings.HasSuffix(source, gzipExt) {
+		return "", fmt.Errorf("%s is a gzip-compressed file", source)
+	}
 
 	dest = filepath.Join(dest, source+gzipExt)
 	return dest, nil
@@ -132,8 +148,11 @@ func main() {
 	var level int
 	var path string
 	var target = "."
+	var err error
+	var unrestrict bool
 
 	flag.IntVar(&level, "l", flate.DefaultCompression, "compression level")
+	flag.BoolVar(&unrestrict, "u", false, "do not restrict decompression")
 	flag.Parse()
 
 	if flag.NArg() < 1 || flag.NArg() > 2 {
@@ -147,30 +166,31 @@ func main() {
 	}
 
 	if strings.HasSuffix(path, gzipExt) {
-		target, err := pathForUncompressing(path, target)
+		target, err = pathForUncompressing(path, target)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "%s\n", err)
 			os.Exit(1)
 		}
 
-		err = uncompress(path, target)
+		err = uncompress(path, target, unrestrict)
 		if err != nil {
 			os.Remove(target)
 			fmt.Fprintf(os.Stderr, "%s\n", err)
 			os.Exit(1)
 		}
-	} else {
-		target, err := pathForCompressing(path, target)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "%s\n", err)
-			os.Exit(1)
-		}
+		return
+	}
 
-		err = compress(path, target, level)
-		if err != nil {
-			os.Remove(target)
-			fmt.Fprintf(os.Stderr, "%s\n", err)
-			os.Exit(1)
-		}
+	target, err = pathForCompressing(path, target)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+		os.Exit(1)
+	}
+
+	err = compress(path, target, level)
+	if err != nil {
+		os.Remove(target)
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+		os.Exit(1)
 	}
 }

cmd/minmax/main.go

@@ -40,14 +40,14 @@ func main() {
 		usage()
 	}
 
-	min, err := strconv.Atoi(flag.Arg(1))
+	minVal, err := strconv.Atoi(flag.Arg(1))
 	dieIf(err)
 
-	max, err := strconv.Atoi(flag.Arg(2))
+	maxVal, err := strconv.Atoi(flag.Arg(2))
 	dieIf(err)
 
 	code := kind << 6
-	code += (min << 3)
-	code += max
-	fmt.Printf("%0o\n", code)
+	code += (minVal << 3)
+	code += maxVal
+	fmt.Fprintf(os.Stdout, "%0o\n", code)
 }

cmd/parts/main.go

@@ -5,7 +5,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -47,7 +46,7 @@ func help(w io.Writer) {
 }
 
 func loadDatabase() {
-	data, err := ioutil.ReadFile(dbFile)
+	data, err := os.ReadFile(dbFile)
 	if err != nil && os.IsNotExist(err) {
 		partsDB = &database{
 			Version: dbVersion,
@@ -74,7 +73,7 @@ func writeDB() {
 	data, err := json.Marshal(partsDB)
 	die.If(err)
 
-	err = ioutil.WriteFile(dbFile, data, 0644)
+	err = os.WriteFile(dbFile, data, 0644)
 	die.If(err)
 }
 

cmd/pem2bin/main.go

@@ -4,14 +4,13 @@ import (
 	"encoding/pem"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 )
 
 var ext = ".bin"
 
 func stripPEM(path string) error {
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		return err
 	}
@@ -22,7 +21,7 @@ func stripPEM(path string) error {
 		fmt.Fprintf(os.Stderr, "          (only the first object will be decoded)\n")
 	}
 
-	return ioutil.WriteFile(path+ext, p.Bytes, 0644)
+	return os.WriteFile(path+ext, p.Bytes, 0644)
 }
 
 func main() {

cmd/pembody/main.go

@@ -3,8 +3,7 @@ package main
 import (
 	"encoding/pem"
 	"flag"
-	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 
 	"git.wntrmute.dev/kyle/goutils/lib"
@@ -21,9 +20,9 @@ func main() {
 
 	path := flag.Arg(0)
 	if path == "-" {
-		in, err = ioutil.ReadAll(os.Stdin)
+		in, err = io.ReadAll(os.Stdin)
 	} else {
-		in, err = ioutil.ReadFile(flag.Arg(0))
+		in, err = os.ReadFile(flag.Arg(0))
 	}
 	if err != nil {
 		lib.Err(lib.ExitFailure, err, "couldn't read file")
@@ -33,5 +32,7 @@ func main() {
 	if p == nil {
 		lib.Errx(lib.ExitFailure, "%s isn't a PEM-encoded file", flag.Arg(0))
 	}
-	fmt.Printf("%s", p.Bytes)
+	if _, err = os.Stdout.Write(p.Bytes); err != nil {
+		lib.Err(lib.ExitFailure, err, "writing body")
+	}
 }

cmd/pemit/main.go

@@ -70,7 +70,7 @@ func main() {
 			lib.Err(lib.ExitFailure, err, "failed to read input")
 		}
 	case argc > 1:
-		for i := 0; i < argc; i++ {
+		for i := range argc {
 			path := flag.Arg(i)
 			err = copyFile(path, buf)
 			if err != nil {

cmd/readchain/main.go

@@ -5,7 +5,6 @@ import (
 	"encoding/pem"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 )
 
@@ -13,14 +12,14 @@ func main() {
 	flag.Parse()
 
 	for _, fileName := range flag.Args() {
-		data, err := ioutil.ReadFile(fileName)
+		data, err := os.ReadFile(fileName)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "[!] %s: %v\n", fileName, err)
 			continue
 		}
 
-		fmt.Printf("[+] %s:\n", fileName)
-		rest := data[:]
+		fmt.Fprintf(os.Stdout, "[+] %s:\n", fileName)
+		rest := data
 		for {
 			var p *pem.Block
 			p, rest = pem.Decode(rest)
@@ -28,13 +27,14 @@ func main() {
 				break
 			}
 
-			cert, err := x509.ParseCertificate(p.Bytes)
+			var cert *x509.Certificate
+			cert, err = x509.ParseCertificate(p.Bytes)
 			if err != nil {
 				fmt.Fprintf(os.Stderr, "[!] %s: %v\n", fileName, err)
 				break
 			}
 
-			fmt.Printf("\t%+v\n", cert.Subject.CommonName)
+			fmt.Fprintf(os.Stdout, "\t%+v\n", cert.Subject.CommonName)
 		}
 	}
 }

cmd/renfnv/main.go

@@ -43,7 +43,7 @@ func newName(path string) (string, error) {
 	return hashName(path, encodedHash), nil
 }
 
-func move(dst, src string, force bool) (err error) {
+func move(dst, src string, force bool) error {
 	if fileutil.FileDoesExist(dst) && !force {
 		return fmt.Errorf("%s exists (pass the -f flag to overwrite)", dst)
 	}
@@ -52,21 +52,23 @@ func move(dst, src string, force bool) (err error) {
 		return err
 	}
 
-	defer func(e error) {
+	var retErr error
+	defer func(e *error) {
 		dstFile.Close()
-		if e != nil {
+		if *e != nil {
 			os.Remove(dst)
 		}
-	}(err)
+	}(&retErr)
 
 	srcFile, err := os.Open(src)
 	if err != nil {
+		retErr = err
 		return err
 	}
 	defer srcFile.Close()
 
-	_, err = io.Copy(dstFile, srcFile)
-	if err != nil {
+	if _, err = io.Copy(dstFile, srcFile); err != nil {
+		retErr = err
 		return err
 	}
 
@@ -94,6 +96,44 @@ func init() {
 	flag.Usage = func() { usage(os.Stdout) }
 }
 
+type options struct {
+	dryRun, force, printChanged, verbose bool
+}
+
+func processOne(file string, opt options) error {
+	renamed, err := newName(file)
+	if err != nil {
+		_, _ = lib.Warn(err, "failed to get new file name")
+		return err
+	}
+	if opt.verbose && !opt.printChanged {
+		fmt.Fprintln(os.Stdout, file)
+	}
+	if renamed == file {
+		return nil
+	}
+	if !opt.dryRun {
+		if err = move(renamed, file, opt.force); err != nil {
+			_, _ = lib.Warn(err, "failed to rename file from %s to %s", file, renamed)
+			return err
+		}
+	}
+	if opt.printChanged && !opt.verbose {
+		fmt.Fprintln(os.Stdout, file, "->", renamed)
+	}
+	return nil
+}
+
+func run(dryRun, force, printChanged, verbose bool, files []string) {
+	if verbose && printChanged {
+		printChanged = false
+	}
+	opt := options{dryRun: dryRun, force: force, printChanged: printChanged, verbose: verbose}
+	for _, file := range files {
+		_ = processOne(file, opt)
+	}
+}
+
 func main() {
 	var dryRun, force, printChanged, verbose bool
 	flag.BoolVar(&force, "f", false, "force overwriting of files if there is a collision")
@@ -102,34 +142,5 @@ func main() {
 	flag.BoolVar(&verbose, "v", false, "list all processed files")
 
 	flag.Parse()
-
-	if verbose && printChanged {
-		printChanged = false
-	}
-
-	for _, file := range flag.Args() {
-		renamed, err := newName(file)
-		if err != nil {
-			lib.Warn(err, "failed to get new file name")
-			continue
-		}
-
-		if verbose && !printChanged {
-			fmt.Println(file)
-		}
-
-		if renamed != file {
-			if !dryRun {
-				err = move(renamed, file, force)
-				if err != nil {
-					lib.Warn(err, "failed to rename file from %s to %s", file, renamed)
-					continue
-				}
-			}
-
-			if printChanged && !verbose {
-				fmt.Println(file, "->", renamed)
-			}
-		}
-	}
+	run(dryRun, force, printChanged, verbose, flag.Args())
 }

cmd/rhash/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"io"
@@ -66,24 +67,25 @@ func main() {
 	for _, remote := range flag.Args() {
 		u, err := url.Parse(remote)
 		if err != nil {
-			lib.Warn(err, "parsing %s", remote)
+			_, _ = lib.Warn(err, "parsing %s", remote)
 			continue
 		}
 
 		name := filepath.Base(u.Path)
 		if name == "" {
-			lib.Warnx("source URL doesn't appear to name a file")
+			_, _ = lib.Warnx("source URL doesn't appear to name a file")
 			continue
 		}
 
-		resp, err := http.Get(remote)
-		if err != nil {
-			lib.Warn(err, "fetching %s", remote)
+		req, reqErr := http.NewRequestWithContext(context.Background(), http.MethodGet, remote, nil)
+		if reqErr != nil {
+			_, _ = lib.Warn(reqErr, "building request for %s", remote)
 			continue
 		}
-
+		client := &http.Client{}
+		resp, err := client.Do(req)
 		if err != nil {
-			lib.Warn(err, "fetching %s", remote)
+			_, _ = lib.Warn(err, "fetching %s", remote)
 			continue
 		}
 

cmd/rolldie/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
-	"math/rand"
+	"math/rand/v2"
 	"os"
 	"regexp"
 	"strconv"
@@ -17,8 +17,8 @@ func rollDie(count, sides int) []int {
 	sum := 0
 	var rolls []int
 
-	for i := 0; i < count; i++ {
-		roll := rand.Intn(sides) + 1
+	for range count {
+		roll := rand.IntN(sides) + 1 // #nosec G404
 		sum += roll
 		rolls = append(rolls, roll)
 	}

cmd/showimp/main.go

@@ -53,7 +53,7 @@ func init() {
 	project = wd[len(gopath):]
 }
 
-func walkFile(path string, info os.FileInfo, err error) error {
+func walkFile(path string, _ os.FileInfo, err error) error {
 	if ignores[path] {
 		return filepath.SkipDir
 	}
@@ -62,22 +62,27 @@ func walkFile(path string, info os.FileInfo, err error) error {
 		return nil
 	}
 
-	debug.Println(path)
-
-	f, err := parser.ParseFile(fset, path, nil, parser.ImportsOnly)
 	if err != nil {
 		return err
 	}
 
+	debug.Println(path)
+
+	f, err2 := parser.ParseFile(fset, path, nil, parser.ImportsOnly)
+	if err2 != nil {
+		return err2
+	}
+
 	for _, importSpec := range f.Imports {
 		importPath := strings.Trim(importSpec.Path.Value, `"`)
-		if stdLibRegexp.MatchString(importPath) {
+		switch {
+		case stdLibRegexp.MatchString(importPath):
 			debug.Println("standard lib:", importPath)
 			continue
-		} else if strings.HasPrefix(importPath, project) {
+		case strings.HasPrefix(importPath, project):
 			debug.Println("internal import:", importPath)
 			continue
-		} else if strings.HasPrefix(importPath, "golang.org/") {
+		case strings.HasPrefix(importPath, "golang.org/"):
 			debug.Println("extended lib:", importPath)
 			continue
 		}
@@ -102,7 +107,7 @@ func main() {
 		ignores["vendor"] = true
 	}
 
-	for _, word := range strings.Split(ignoreLine, ",") {
+	for word := range strings.SplitSeq(ignoreLine, ",") {
 		ignores[strings.TrimSpace(word)] = true
 	}
 

cmd/ski/main.go

@@ -2,10 +2,9 @@ package main
 
 import (
 	"bytes"
-	"crypto"
 	"crypto/ecdsa"
 	"crypto/rsa"
-	"crypto/sha1"
+	"crypto/sha1" // #nosec G505
 	"crypto/x509"
 	"crypto/x509/pkix"
 	"encoding/asn1"
@@ -13,14 +12,18 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
-	"strings"
 
+	"git.wntrmute.dev/kyle/goutils/certlib"
 	"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
 
@@ -28,10 +31,10 @@ 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.
-
 `)
 }
 
@@ -39,14 +42,14 @@ func init() {
 	flag.Usage = func() { usage(os.Stderr) }
 }
 
-func parse(path string) (public []byte, kt, ft string) {
-	data, err := ioutil.ReadFile(path)
+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")
+		_, _ = lib.Warnx("trailing data in PEM file")
 	}
 
 	if p == nil {
@@ -55,6 +58,12 @@ func parse(path string) (public []byte, kt, ft string) {
 
 	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)
@@ -69,84 +78,74 @@ func parse(path string) (public []byte, kt, ft string) {
 		die.With("unknown PEM type %s", p.Type)
 	}
 
-	return
+	return public, kt, ft
 }
 
-func parseKey(data []byte) (public []byte, kt string) {
-	privInterface, err := x509.ParsePKCS8PrivateKey(data)
+func parseKey(data []byte) ([]byte, string) {
+	priv, err := certlib.ParsePrivateKeyDER(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.")
-			}
-		}
+		die.If(err)
 	}
 
-	var priv crypto.Signer
-	switch privInterface.(type) {
-	case *rsa.PrivateKey:
-		priv = privInterface.(*rsa.PrivateKey)
-		kt = "RSA"
-	case *ecdsa.PrivateKey:
-		priv = privInterface.(*ecdsa.PrivateKey)
-		kt = "ECDSA"
+	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", privInterface)
+		die.With("unknown private key type %T", priv)
 	}
 
-	public, err = x509.MarshalPKIXPublicKey(priv.Public())
+	public, err := x509.MarshalPKIXPublicKey(priv.Public())
 	die.If(err)
 
-	return
+	return public, kt
 }
 
-func parseCertificate(data []byte) (public []byte, kt string) {
+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 = "RSA"
+		kt = keyTypeRSA
 	case *ecdsa.PublicKey:
-		kt = "ECDSA"
+		kt = keyTypeECDSA
 	default:
 		die.With("unknown public key type %T", pub)
 	}
 
-	public, err = x509.MarshalPKIXPublicKey(pub)
+	public, err := x509.MarshalPKIXPublicKey(pub)
 	die.If(err)
-	return
+	return public, kt
 }
 
-func parseCSR(data []byte) (public []byte, kt string) {
-	csr, err := x509.ParseCertificateRequest(data)
+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 = "RSA"
+		kt = keyTypeRSA
 	case *ecdsa.PublicKey:
-		kt = "ECDSA"
+		kt = keyTypeECDSA
 	default:
 		die.With("unknown public key type %T", pub)
 	}
 
-	public, err = x509.MarshalPKIXPublicKey(pub)
+	public, err := x509.MarshalPKIXPublicKey(pub)
 	die.If(err)
-	return
+	return public, kt
 }
 
-func dumpHex(in []byte) string {
-	var s string
-	for i := range in {
-		s += fmt.Sprintf("%02X:", in[i])
-	}
-
-	return strings.Trim(s, ":")
+func dumpHex(in []byte, mode lib.HexEncodeMode) string {
+	return lib.HexEncode(in, mode)
 }
 
 type subjectPublicKeyInfo struct {
@@ -156,10 +155,14 @@ type subjectPublicKeyInfo struct {
 
 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)
@@ -172,18 +175,18 @@ func main() {
 		var subPKI subjectPublicKeyInfo
 		_, err := asn1.Unmarshal(public, &subPKI)
 		if err != nil {
-			lib.Warn(err, "failed to get subject PKI")
+			_, _ = lib.Warn(err, "failed to get subject PKI")
 			continue
 		}
 
-		pubHash := sha1.Sum(subPKI.SubjectPublicKey.Bytes)
-		pubHashString := dumpHex(pubHash[:])
+		pubHash := sha1.Sum(subPKI.SubjectPublicKey.Bytes) // #nosec G401 this is the standard
+		pubHashString := dumpHex(pubHash[:], displayMode)
 		if ski == "" {
 			ski = pubHashString
 		}
 
 		if shouldMatch && ski != pubHashString {
-			lib.Warnx("%s: SKI mismatch (%s != %s)",
+			_, _ = lib.Warnx("%s: SKI mismatch (%s != %s)",
 				path, ski, pubHashString)
 		}
 		fmt.Printf("%s  %s (%s %s)\n", path, pubHashString, kt, ft)

cmd/sprox/main.go

@@ -1,16 +1,17 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"io"
-	"log"
 	"net"
 
 	"git.wntrmute.dev/kyle/goutils/die"
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
 func proxy(conn net.Conn, inside string) error {
-	proxyConn, err := net.Dial("tcp", inside)
+	proxyConn, err := (&net.Dialer{}).DialContext(context.Background(), "tcp", inside)
 	if err != nil {
 		return err
 	}
@@ -19,7 +20,7 @@ func proxy(conn net.Conn, inside string) error {
 	defer conn.Close()
 
 	go func() {
-		io.Copy(conn, proxyConn)
+		_, _ = io.Copy(conn, proxyConn)
 	}()
 	_, err = io.Copy(proxyConn, conn)
 	return err
@@ -31,16 +32,22 @@ func main() {
 	flag.StringVar(&inside, "p", "4000", "inside port")
 	flag.Parse()
 
-	l, err := net.Listen("tcp", "0.0.0.0:"+outside)
+	lc := &net.ListenConfig{}
+	l, err := lc.Listen(context.Background(), "tcp", "0.0.0.0:"+outside)
 	die.If(err)
 
 	for {
-		conn, err := l.Accept()
+		var conn net.Conn
+		conn, err = l.Accept()
 		if err != nil {
-			log.Println(err)
+			_, _ = lib.Warn(err, "accept failed")
 			continue
 		}
 
-		go proxy(conn, "127.0.0.1:"+inside)
+		go func() {
+			if err = proxy(conn, "127.0.0.1:"+inside); err != nil {
+				_, _ = lib.Warn(err, "proxy error")
+			}
+		}()
 	}
 }

cmd/stealchain-server/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"crypto/rand"
 	"crypto/tls"
 	"crypto/x509"
@@ -8,7 +9,6 @@ import (
 	"encoding/pem"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 
@@ -16,7 +16,7 @@ import (
 )
 
 func main() {
-	cfg := &tls.Config{}
+	cfg := &tls.Config{} // #nosec G402
 
 	var sysRoot, listenAddr, certFile, keyFile string
 	var verify bool
@@ -47,7 +47,8 @@ func main() {
 	}
 	cfg.Certificates = append(cfg.Certificates, cert)
 	if sysRoot != "" {
-		pemList, err := ioutil.ReadFile(sysRoot)
+		var pemList []byte
+		pemList, err = os.ReadFile(sysRoot)
 		die.If(err)
 
 		roots := x509.NewCertPool()
@@ -59,48 +60,54 @@ func main() {
 		cfg.RootCAs = roots
 	}
 
-	l, err := net.Listen("tcp", listenAddr)
+	lc := &net.ListenConfig{}
+	l, err := lc.Listen(context.Background(), "tcp", listenAddr)
 	if err != nil {
 		fmt.Println(err.Error())
 		os.Exit(1)
 	}
 
 	for {
-		conn, err := l.Accept()
+		var conn net.Conn
+		conn, err = l.Accept()
 		if err != nil {
 			fmt.Println(err.Error())
-		}
-
-		raddr := conn.RemoteAddr()
-		tconn := tls.Server(conn, cfg)
-		err = tconn.Handshake()
-		if err != nil {
-			fmt.Printf("[+] %v: failed to complete handshake: %v\n", raddr, err)
 			continue
 		}
-		cs := tconn.ConnectionState()
-		if len(cs.PeerCertificates) == 0 {
-			fmt.Printf("[+] %v: no chain presented\n", raddr)
-			continue
-		}
-
-		var chain []byte
-		for _, cert := range cs.PeerCertificates {
-			p := &pem.Block{
-				Type:  "CERTIFICATE",
-				Bytes: cert.Raw,
-			}
-			chain = append(chain, pem.EncodeToMemory(p)...)
-		}
-
-		var nonce [16]byte
-		_, err = rand.Read(nonce[:])
-		if err != nil {
-			panic(err)
-		}
-		fname := fmt.Sprintf("%v-%v.pem", raddr, hex.EncodeToString(nonce[:]))
-		err = ioutil.WriteFile(fname, chain, 0644)
-		die.If(err)
-		fmt.Printf("%v: [+] wrote %v.\n", raddr, fname)
+		handleConn(conn, cfg)
 	}
 }
+
+// handleConn performs a TLS handshake, extracts the peer chain, and writes it to a file.
+func handleConn(conn net.Conn, cfg *tls.Config) {
+	defer conn.Close()
+	raddr := conn.RemoteAddr()
+	tconn := tls.Server(conn, cfg)
+	if err := tconn.HandshakeContext(context.Background()); err != nil {
+		fmt.Printf("[+] %v: failed to complete handshake: %v\n", raddr, err)
+		return
+	}
+	cs := tconn.ConnectionState()
+	if len(cs.PeerCertificates) == 0 {
+		fmt.Printf("[+] %v: no chain presented\n", raddr)
+		return
+	}
+
+	var chain []byte
+	for _, cert := range cs.PeerCertificates {
+		p := &pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw}
+		chain = append(chain, pem.EncodeToMemory(p)...)
+	}
+
+	var nonce [16]byte
+	if _, err := rand.Read(nonce[:]); err != nil {
+		fmt.Printf("[+] %v: failed to generate filename nonce: %v\n", raddr, err)
+		return
+	}
+	fname := fmt.Sprintf("%v-%v.pem", raddr, hex.EncodeToString(nonce[:]))
+	if err := os.WriteFile(fname, chain, 0o644); err != nil {
+		fmt.Printf("[+] %v: failed to write %v: %v\n", raddr, fname, err)
+		return
+	}
+	fmt.Printf("%v: [+] wrote %v.\n", raddr, fname)
+}

cmd/stealchain/main.go

@@ -1,12 +1,12 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 
@@ -14,7 +14,7 @@ import (
 )
 
 func main() {
-	var cfg = &tls.Config{}
+	var cfg = &tls.Config{} // #nosec G402
 
 	var sysRoot, serverName string
 	flag.StringVar(&sysRoot, "ca", "", "provide an alternate CA bundle")
@@ -23,7 +23,7 @@ func main() {
 	flag.Parse()
 
 	if sysRoot != "" {
-		pemList, err := ioutil.ReadFile(sysRoot)
+		pemList, err := os.ReadFile(sysRoot)
 		die.If(err)
 
 		roots := x509.NewCertPool()
@@ -44,10 +44,13 @@ func main() {
 		if err != nil {
 			site += ":443"
 		}
-		conn, err := tls.Dial("tcp", site, cfg)
-		if err != nil {
-			fmt.Println(err.Error())
-			os.Exit(1)
+		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)")
 		}
 
 		cs := conn.ConnectionState()
@@ -61,8 +64,9 @@ func main() {
 			chain = append(chain, pem.EncodeToMemory(p)...)
 		}
 
-		err = ioutil.WriteFile(site+".pem", chain, 0644)
+		err = os.WriteFile(site+".pem", chain, 0644)
 		die.If(err)
+
 		fmt.Printf("[+] wrote %s.pem.\n", site)
 	}
 }

cmd/subjhash/main.go

@@ -60,7 +60,7 @@ func printDigests(paths []string, issuer bool) {
 	for _, path := range paths {
 		cert, err := certlib.LoadCertificate(path)
 		if err != nil {
-			lib.Warn(err, "failed to load certificate from %s", path)
+			_, _ = lib.Warn(err, "failed to load certificate from %s", path)
 			continue
 		}
 
@@ -75,20 +75,19 @@ func matchDigests(paths []string, issuer bool) {
 	}
 
 	var invalid int
-	for {
-		if len(paths) == 0 {
-			break
-		}
+	for len(paths) > 0 {
 		fst := paths[0]
 		snd := paths[1]
 		paths = paths[2:]
 
 		fstCert, err := certlib.LoadCertificate(fst)
 		die.If(err)
+
 		sndCert, err := certlib.LoadCertificate(snd)
 		die.If(err)
+
 		if !bytes.Equal(getSubjectInfoHash(fstCert, issuer), getSubjectInfoHash(sndCert, issuer)) {
-			lib.Warnx("certificates don't match: %s and %s", fst, snd)
+			_, _ = lib.Warnx("certificates don't match: %s and %s", fst, snd)
 			invalid++
 		}
 	}

cmd/tlsinfo/main.go

@@ -1,10 +1,14 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
 	"os"
+
+	"git.wntrmute.dev/kyle/goutils/certlib/hosts"
+	"git.wntrmute.dev/kyle/goutils/die"
 )
 
 func main() {
@@ -13,16 +17,23 @@ func main() {
 		os.Exit(1)
 	}
 
-	hostPort := os.Args[1]
-	conn, err := tls.Dial("tcp", hostPort, &tls.Config{
-		InsecureSkipVerify: true,
-	})
+	hostPort, err := hosts.ParseHost(os.Args[1])
+	die.If(err)
 
-	if err != nil {
-		fmt.Printf("Failed to connect to the TLS server: %v\n", err)
-		os.Exit(1)
+	d := &tls.Dialer{Config: &tls.Config{
+		InsecureSkipVerify: true,
+	}} // #nosec G402
+
+	nc, err := d.DialContext(context.Background(), "tcp", hostPort.String())
+	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()
 	printConnectionDetails(state)
 }
@@ -37,7 +48,6 @@ func printConnectionDetails(state tls.ConnectionState) {
 
 func tlsVersion(version uint16) string {
 	switch version {
-
 	case tls.VersionTLS13:
 		return "TLS 1.3"
 	case tls.VersionTLS12:

cmd/tlskeypair/main.go

@@ -11,10 +11,9 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"io/ioutil"
-	"log"
 	"os"
 
+	"git.wntrmute.dev/kyle/goutils/certlib"
 	"git.wntrmute.dev/kyle/goutils/die"
 )
 
@@ -32,7 +31,7 @@ const (
 	curveP521
 )
 
-func getECCurve(pub interface{}) int {
+func getECCurve(pub any) int {
 	switch pub := pub.(type) {
 	case *ecdsa.PublicKey:
 		switch pub.Curve {
@@ -52,42 +51,88 @@ func getECCurve(pub interface{}) int {
 	}
 }
 
+// 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 := ioutil.ReadFile(path)
+	in, err := os.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}
 
 	in = bytes.TrimSpace(in)
-	p, _ := pem.Decode(in)
-	if p != nil {
+	if p, _ := pem.Decode(in); p != nil {
 		if !validPEMs[p.Type] {
 			return nil, errors.New("invalid private key file type " + p.Type)
 		}
-		in = p.Bytes
+		return certlib.ParsePrivateKeyPEM(in)
 	}
 
-	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 priv.(type) {
-	case *rsa.PrivateKey:
-		return priv.(*rsa.PrivateKey), nil
-	case *ecdsa.PrivateKey:
-		return priv.(*ecdsa.PrivateKey), nil
-	}
-
-	// should never reach here
-	return nil, errors.New("invalid private key")
-
+	return certlib.ParsePrivateKeyDER(in)
 }
 
 func main() {
@@ -96,7 +141,7 @@ func main() {
 	flag.StringVar(&certFile, "c", "", "TLS `certificate` file")
 	flag.Parse()
 
-	in, err := ioutil.ReadFile(certFile)
+	in, err := os.ReadFile(certFile)
 	die.If(err)
 
 	p, _ := pem.Decode(in)
@@ -112,50 +157,11 @@ func main() {
 	priv, err := loadKey(keyFile)
 	die.If(err)
 
-	switch pub := priv.Public().(type) {
-	case *rsa.PublicKey:
-		switch certPub := cert.PublicKey.(type) {
-		case *rsa.PublicKey:
-			if pub.N.Cmp(certPub.N) != 0 || pub.E != certPub.E {
-				fmt.Println("No match (public keys don't match).")
-				os.Exit(1)
-			}
-			fmt.Println("Match.")
-			return
-		case *ecdsa.PublicKey:
-			fmt.Println("No match (RSA private key, EC public key).")
-			os.Exit(1)
-		}
-	case *ecdsa.PublicKey:
-		privCurve := getECCurve(pub)
-		certCurve := getECCurve(cert.PublicKey)
-		log.Printf("priv: %d\tcert: %d\n", privCurve, certCurve)
-
-		if certCurve == curveRSA {
-			fmt.Println("No match (private key is EC, certificate is RSA).")
-			os.Exit(1)
-		} else if privCurve == curveInvalid {
-			fmt.Println("No match (invalid private key curve).")
-			os.Exit(1)
-		} else if privCurve != certCurve {
-			fmt.Println("No match (EC curves don't match).")
-			os.Exit(1)
-		}
-
-		certPub := cert.PublicKey.(*ecdsa.PublicKey)
-		if pub.X.Cmp(certPub.X) != 0 {
-			fmt.Println("No match (public keys don't match).")
-			os.Exit(1)
-		}
-
-		if pub.Y.Cmp(certPub.Y) != 0 {
-			fmt.Println("No match (public keys don't match).")
-			os.Exit(1)
-		}
-
+	matched, reason := matchKeys(cert, priv)
+	if matched {
 		fmt.Println("Match.")
-	default:
-		fmt.Printf("Unrecognised private key type: %T\n", priv.Public())
-		os.Exit(1)
+		return
 	}
+	fmt.Printf("No match (%s).\n", reason)
+	os.Exit(1)
 }

cmd/utc/main.go

@@ -201,10 +201,6 @@ func init() {
 			os.Exit(1)
 		}
 
-		if fromLoc == time.UTC {
-
-		}
-
 		toLoc = time.UTC
 	}
 
@@ -257,15 +253,16 @@ func main() {
 		showTime(time.Now())
 		os.Exit(0)
 	case 1:
-		if flag.Arg(0) == "-" {
+		switch {
+		case flag.Arg(0) == "-":
 			s := bufio.NewScanner(os.Stdin)
 
 			for s.Scan() {
 				times = append(times, s.Text())
 			}
-		} else if flag.Arg(0) == "help" {
+		case flag.Arg(0) == "help":
 			usageExamples()
-		} else {
+		default:
 			times = flag.Args()
 		}
 	default:

cmd/yamll/main.go

@@ -4,7 +4,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 
 	"gopkg.in/yaml.v2"
@@ -12,9 +11,8 @@ import (
 
 type empty struct{}
 
-func errorf(format string, args ...interface{}) {
-	format += "\n"
-	fmt.Fprintf(os.Stderr, format, args...)
+func errorf(path string, err error) {
+	fmt.Fprintf(os.Stderr, "%s FAILED: %s\n", path, err)
 }
 
 func usage(w io.Writer) {
@@ -44,16 +42,16 @@ func main() {
 
 	if flag.NArg() == 1 && flag.Arg(0) == "-" {
 		path := "stdin"
-		in, err := ioutil.ReadAll(os.Stdin)
+		in, err := io.ReadAll(os.Stdin)
 		if err != nil {
-			errorf("%s FAILED: %s", path, err)
+			errorf(path, err)
 			os.Exit(1)
 		}
 
 		var e empty
 		err = yaml.Unmarshal(in, &e)
 		if err != nil {
-			errorf("%s FAILED: %s", path, err)
+			errorf(path, err)
 			os.Exit(1)
 		}
 
@@ -65,16 +63,16 @@ func main() {
 	}
 
 	for _, path := range flag.Args() {
-		in, err := ioutil.ReadFile(path)
+		in, err := os.ReadFile(path)
 		if err != nil {
-			errorf("%s FAILED: %s", path, err)
+			errorf(path, err)
 			continue
 		}
 
 		var e empty
 		err = yaml.Unmarshal(in, &e)
 		if err != nil {
-			errorf("%s FAILED: %s", path, err)
+			errorf(path, err)
 			continue
 		}
 

cmd/zsearch/main.go

@@ -14,16 +14,16 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
 const defaultDirectory = ".git/objects"
 
-func errorf(format string, a ...interface{}) {
-	fmt.Fprintf(os.Stderr, format, a...)
-	if format[len(format)-1] != '\n' {
-		fmt.Fprintf(os.Stderr, "\n")
-	}
-}
+// maxDecompressedSize limits how many bytes we will decompress from a zlib
+// stream to mitigate decompression bombs (gosec G110).
+// Increase this if you expect larger objects.
+const maxDecompressedSize int64 = 64 << 30 // 64 GiB
 
 func isDir(path string) bool {
 	fi, err := os.Stat(path)
@@ -48,17 +48,21 @@ func loadFile(path string) ([]byte, error) {
 	}
 	defer zread.Close()
 
-	_, err = io.Copy(buf, zread)
-	if err != nil {
+	// Protect against decompression bombs by limiting how much we read.
+	lr := io.LimitReader(zread, maxDecompressedSize+1)
+	if _, err = buf.ReadFrom(lr); err != nil {
 		return nil, err
 	}
+	if int64(buf.Len()) > maxDecompressedSize {
+		return nil, fmt.Errorf("decompressed size exceeds limit (%d bytes)", maxDecompressedSize)
+	}
 	return buf.Bytes(), nil
 }
 
 func showFile(path string) {
 	fileData, err := loadFile(path)
 	if err != nil {
-		errorf("%v", err)
+		lib.Warn(err, "failed to load %s", path)
 		return
 	}
 
@@ -68,39 +72,71 @@ func showFile(path string) {
 func searchFile(path string, search *regexp.Regexp) error {
 	file, err := os.Open(path)
 	if err != nil {
-		errorf("%v", err)
+		lib.Warn(err, "failed to open %s", path)
 		return err
 	}
 	defer file.Close()
 
 	zread, err := zlib.NewReader(file)
 	if err != nil {
-		errorf("%v", err)
+		lib.Warn(err, "failed to decompress %s", path)
 		return err
 	}
 	defer zread.Close()
 
-	zbuf := bufio.NewReader(zread)
-	if search.MatchReader(zbuf) {
-		fileData, err := loadFile(path)
-		if err != nil {
-			errorf("%v", err)
-			return err
-		}
-		fmt.Printf("%s:\n%s\n", path, fileData)
+	// Limit how much we scan to avoid DoS via huge decompression.
+	lr := io.LimitReader(zread, maxDecompressedSize+1)
+	zbuf := bufio.NewReader(lr)
+	if !search.MatchReader(zbuf) {
+		return nil
 	}
+
+	fileData, err := loadFile(path)
+	if err != nil {
+		lib.Warn(err, "failed to load %s", path)
+		return err
+	}
+	fmt.Printf("%s:\n%s\n", path, fileData)
 	return nil
 }
 
 func buildWalker(searchExpr *regexp.Regexp) filepath.WalkFunc {
-	return func(path string, info os.FileInfo, err error) error {
-		if info.Mode().IsRegular() {
-			return searchFile(path, searchExpr)
+	return func(path string, info os.FileInfo, _ error) error {
+		if !info.Mode().IsRegular() {
+			return nil
 		}
-		return nil
+		return searchFile(path, searchExpr)
 	}
 }
 
+// runSearch compiles the search expression and processes the provided paths.
+// It returns an error for fatal conditions; per-file errors are logged.
+func runSearch(expr string) error {
+	search, err := regexp.Compile(expr)
+	if err != nil {
+		return fmt.Errorf("invalid regexp: %w", err)
+	}
+
+	pathList := flag.Args()
+	if len(pathList) == 0 {
+		pathList = []string{defaultDirectory}
+	}
+
+	for _, path := range pathList {
+		if isDir(path) {
+			if err2 := filepath.Walk(path, buildWalker(search)); err2 != nil {
+				return err2
+			}
+			continue
+		}
+		if err2 := searchFile(path, search); err2 != nil {
+			// Non-fatal: keep going, but report it.
+			lib.Warn(err2, "non-fatal error while searching files")
+		}
+	}
+	return nil
+}
+
 func main() {
 	flSearch := flag.String("s", "", "search string (should be an RE2 regular expression)")
 	flag.Parse()
@@ -109,28 +145,10 @@ func main() {
 		for _, path := range flag.Args() {
 			showFile(path)
 		}
-	} else {
-		search, err := regexp.Compile(*flSearch)
-		if err != nil {
-			errorf("Bad regexp: %v", err)
-			return
-		}
+		return
+	}
 
-		pathList := flag.Args()
-		if len(pathList) == 0 {
-			pathList = []string{defaultDirectory}
-		}
-
-		for _, path := range pathList {
-			if isDir(path) {
-				err := filepath.Walk(path, buildWalker(search))
-				if err != nil {
-					errorf("%v", err)
-					return
-				}
-			} else {
-				searchFile(path, search)
-			}
-		}
+	if err := runSearch(*flSearch); err != nil {
+		lib.Err(lib.ExitFailure, err, "failed to run search")
 	}
 }

go.mod

@@ -15,6 +15,7 @@ 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

@@ -44,3 +44,5 @@ 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/ftime_bsd.go

@@ -1,4 +1,4 @@
-// +build freebsd darwin,386 netbsd
+//go:build bsd
 
 package lib
 

lib/ftime_unix.go

@@ -1,4 +1,4 @@
-// +build unix linux openbsd darwin,amd64
+//go:build unix || linux || openbsd || (darwin && amd64)
 
 package lib
 
@@ -18,7 +18,7 @@ type FileTime struct {
 
 func timeSpecToTime(ts unix.Timespec) time.Time {
 	// The casts to int64 are needed because on 386, these are int32s.
-	return time.Unix(int64(ts.Sec), int64(ts.Nsec))
+	return time.Unix(ts.Sec, ts.Nsec)
 }
 
 // LoadFileTime returns a FileTime associated with the file.

lib/lib.go

@@ -2,14 +2,22 @@
 package lib
 
 import (
+	"encoding/hex"
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 )
 
 var progname = filepath.Base(os.Args[0])
 
+const (
+	daysInYear        = 365
+	digitWidth        = 10
+	hoursInQuarterDay = 6
+)
+
 // ProgName returns what lib thinks the program name is, namely the
 // basename of argv0.
 //
@@ -20,7 +28,7 @@ func ProgName() string {
 
 // Warnx displays a formatted error message to standard error, à la
 // warnx(3).
-func Warnx(format string, a ...interface{}) (int, error) {
+func Warnx(format string, a ...any) (int, error) {
 	format = fmt.Sprintf("[%s] %s", progname, format)
 	format += "\n"
 	return fmt.Fprintf(os.Stderr, format, a...)
@@ -28,7 +36,7 @@ func Warnx(format string, a ...interface{}) (int, error) {
 
 // Warn displays a formatted error message to standard output,
 // appending the error string, à la warn(3).
-func Warn(err error, format string, a ...interface{}) (int, error) {
+func Warn(err error, format string, a ...any) (int, error) {
 	format = fmt.Sprintf("[%s] %s", progname, format)
 	format += ": %v\n"
 	a = append(a, err)
@@ -37,7 +45,7 @@ func Warn(err error, format string, a ...interface{}) (int, error) {
 
 // Errx displays a formatted error message to standard error and exits
 // with the status code from `exit`, à la errx(3).
-func Errx(exit int, format string, a ...interface{}) {
+func Errx(exit int, format string, a ...any) {
 	format = fmt.Sprintf("[%s] %s", progname, format)
 	format += "\n"
 	fmt.Fprintf(os.Stderr, format, a...)
@@ -47,7 +55,7 @@ func Errx(exit int, format string, a ...interface{}) {
 // Err displays a formatting error message to standard error,
 // appending the error string, and exits with the status code from
 // `exit`, à la err(3).
-func Err(exit int, err error, format string, a ...interface{}) {
+func Err(exit int, err error, format string, a ...any) {
 	format = fmt.Sprintf("[%s] %s", progname, format)
 	format += ": %v\n"
 	a = append(a, err)
@@ -62,30 +70,30 @@ func Itoa(i int, wid int) string {
 	// Assemble decimal in reverse order.
 	var b [20]byte
 	bp := len(b) - 1
-	for i >= 10 || wid > 1 {
+	for i >= digitWidth || wid > 1 {
 		wid--
-		q := i / 10
-		b[bp] = byte('0' + i - q*10)
+		q := i / digitWidth
+		b[bp] = byte('0' + i - q*digitWidth)
 		bp--
 		i = q
 	}
-	// i < 10
+
 	b[bp] = byte('0' + i)
 	return string(b[bp:])
 }
 
 var (
 	dayDuration  = 24 * time.Hour
-	yearDuration = (365 * dayDuration) + (6 * time.Hour)
+	yearDuration = (daysInYear * dayDuration) + (hoursInQuarterDay * time.Hour)
 )
 
 // Duration returns a prettier string for time.Durations.
 func Duration(d time.Duration) string {
 	var s string
 	if d >= yearDuration {
-		years := d / yearDuration
+		years := int64(d / yearDuration)
 		s += fmt.Sprintf("%dy", years)
-		d -= years * yearDuration
+		d -= time.Duration(years) * yearDuration
 	}
 
 	if d >= dayDuration {
@@ -98,8 +106,135 @@ func Duration(d time.Duration) string {
 	}
 
 	d %= 1 * time.Second
-	hours := d / time.Hour
-	d -= hours * time.Hour
+	hours := int64(d / time.Hour)
+	d -= time.Duration(hours) * time.Hour
 	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
+)
+
+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"
+	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
+	}
+
+	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.
+func HexEncode(b []byte, mode HexEncodeMode) string {
+	str := hexEncode(b)
+
+	switch mode {
+	case HexEncodeLower:
+		return str
+	case HexEncodeUpper:
+		return strings.ToUpper(str)
+	case HexEncodeLowerColon:
+		return hexColons(str)
+	case HexEncodeUpperColon:
+		return strings.ToUpper(hexColons(str))
+	case HexEncodeBytes:
+		return bytesAsByteSliceString(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))
+}

logging/file.go

@@ -1,8 +1,9 @@
 package logging
 
 import (
-    "fmt"
-    "os"
+	"errors"
+	"fmt"
+	"os"
 )
 
 // File writes its logs to file.
@@ -59,12 +60,12 @@ func NewSplitFile(outpath, errpath string, overwrite bool) (*File, error) {
 		fl.fe, err = os.OpenFile(errpath, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0600)
 	}
 
- if err != nil {
-        if closeErr := fl.Close(); closeErr != nil {
-            return nil, fmt.Errorf("failed to open error log: cleanup close failed: %v: %w", closeErr, err)
-        }
-        return nil, err
-    }
+	if err != nil {
+		if closeErr := fl.Close(); closeErr != nil {
+			return nil, fmt.Errorf("failed to open error log: %w", errors.Join(closeErr, err))
+		}
+		return nil, fmt.Errorf("failed to open error log: %w", err)
+	}
 
 	fl.LogWriter = NewLogWriter(fl.fo, fl.fe)
 	return fl, nil
@@ -94,13 +95,13 @@ func (fl *File) Flush() error {
 }
 
 func (fl *File) Chmod(mode os.FileMode) error {
-    if err := fl.fo.Chmod(mode); err != nil {
-        return fmt.Errorf("failed to chmod output log: %w", err)
-    }
+	if err := fl.fo.Chmod(mode); err != nil {
+		return fmt.Errorf("failed to chmod output log: %w", err)
+	}
 
-    if err := fl.fe.Chmod(mode); err != nil {
-        return fmt.Errorf("failed to chmod error log: %w", err)
-    }
+	if err := fl.fe.Chmod(mode); err != nil {
+		return fmt.Errorf("failed to chmod error log: %w", err)
+	}
 
-    return nil
+	return nil
 }

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)
+			}
+		}
+	}
+}