Update CHANGELOG for v1.14.5.

.golangci.yml

@@ -247,11 +247,12 @@ linters:
       # Default: false
       check-type-assertions: true
       exclude-functions:
-        - (*git.wntrmute.dev/kyle/goutils/sbuf.Buffer).Write
+        - (*git.wntrmute.dev/kyle/goutils/dbg.DebugPrinter).Write
         - git.wntrmute.dev/kyle/goutils/lib.Warn
         - git.wntrmute.dev/kyle/goutils/lib.Warnx
         - git.wntrmute.dev/kyle/goutils/lib.Err
         - git.wntrmute.dev/kyle/goutils/lib.Errx
+        - (*git.wntrmute.dev/kyle/goutils/sbuf.Buffer).Write
 
     exhaustive:
       # Program elements to check for exhaustiveness.

.goreleaser.yaml

@@ -419,14 +419,9 @@ builds:
 
 archives:
   - formats: [tar.gz]
-    # this name template makes the OS and Arch compatible with the results of `uname`.
+    # archive filename: name_version_os_arch
     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 }}
+      {{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}{{ if .Arm }}v{{ .Arm }}{{ end }}
     # use zip for windows archives
     format_overrides:
       - goos: windows
@@ -439,13 +434,10 @@ changelog:
       - "^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:
+  github:
+    owner: kisom
+    name: goutils
   footer: >-
 
     ---

CHANGELOG

@@ -1,5 +1,93 @@
 CHANGELOG
 
+v1.14.5 - 2025-11-18
+
+Changed:
+- certlib/verify: fix a nil-pointer dereference.
+
+v1.14.4 - 2025-11-18
+
+Added:
+- certlib/ski: add support for return certificate SKI.
+- certlib/verify: add support for verifying certificates.
+
+Changed:
+- certlib/dump: moved more functions into the dump package.
+- cmd: many certificate-related commands had their functionality moved into
+  certlib.
+
+v1.14.3 - 2025-11-18
+
+Added:
+- certlib/dump: the certificate dumping functions have been moved into
+  their own package.
+
+Changed:
+- cmd/certdump: refactor out most of the functionality into certlib/dump.
+- cmd/kgz: add extended metadata support.
+
+v1.14.2 - 2025-11-18
+
+Added:
+- lib: add tooling for generating baseline TLS configs.
+
+Changed:
+- cmd: update all commands to allow the use strict TLS configs. Note that
+  many of these tools are intended for debugging broken or insecure TLS
+  systems, and the ability to support insecure TLS configurations is
+  important in this regard.
+
+v1.14.1 - 2025-11-18
+
+Added:
+- build: add missing Dockerfile.
+
+v1.14.0 - 2025-11-18
+
+Added:
+- lib/dialer: introduce proxy-aware dialers and helpers:
+  - NewNetDialer and NewTLSDialer honoring SOCKS5_PROXY, HTTPS_PROXY, HTTP_PROXY
+    (case-insensitive) with precedence SOCKS5 > HTTPS > HTTP.
+  - DialTCP and DialTLS convenience functions; DialTLS performs a TLS handshake
+    and returns a concrete *tls.Conn.
+  - NewHTTPClient: returns a proxy-aware *http.Client. Uses SOCKS5 proxy when
+    configured (disables HTTP(S) proxying to avoid double-proxying); otherwise
+    relies on http.ProxyFromEnvironment (respects HTTP(S)_PROXY and NO_PROXY).
+- build: the releasse-docker.sh builds and pushes the correct Docker images.
+
+Changed:
+- cmd: migrate tools to new proxy-aware helpers where appropriate:
+  - certchain, stealchain, tlsinfo: use lib.DialTLS.
+  - cert-revcheck: use lib.DialTLS for site connects and a proxy-aware
+    HTTP client for OCSP/CRL fetches.
+  - rhash: use proxy-aware HTTP client for downloads.
+- lib/fetch: migrate from certlib/fetch.go to lib/fetch.go and use DialTLS
+  under the hood.
+- go.mod: add golang.org/x/net dependency (for SOCKS5 support) and align x/crypto.
+
+Notes:
+- HTTP(S) proxy CONNECT supports optional basic auth via proxy URL credentials.
+- HTTPS proxies are TLS-wrapped prior to CONNECT.
+- Timeouts apply to TCP connects, proxy handshakes, and TLS handshakes; context
+  cancellation is honored.
+- Some commands retain bespoke dialing (e.g., IPv6-only or unix sockets) and
+  were intentionally left unchanged.
+
+v1.13.6 - 2025-11-18
+
+Changed:
+- build: removing gitea stuff.
+
+v1.13.5 - 2025-11-18
+
+Changed:
+- build: updating goreleaser config.
+
+v1.13.4 - 2025-11-18
+
+Changed:
+- build: updating goreleaser config.
+
 v1.13.3 - 2025-11-18
 
 Added:

Dockerfile

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

certlib/dump/dump.go

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

certlib/ski/ski.go

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

certlib/verify/check.go

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

certlib/verify/verify.go

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

cmd/cert-revcheck/main.go

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

cmd/certchain/main.go

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

cmd/certdump/main.go

@@ -2,375 +2,44 @@
 package main
 
 import (
-	"crypto/dsa"
-	"crypto/ecdsa"
-	"crypto/elliptic"
-	"crypto/rsa"
-	"crypto/sha256"
-	"crypto/x509"
-	"crypto/x509/pkix"
+	"crypto/tls"
 	"flag"
 	"fmt"
 	"os"
-	"sort"
-	"strings"
 
-	"github.com/kr/text"
-
-	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/dump"
 	"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 (
+var config struct {
+	showHash   bool
 	dateFormat string
-	showHash   bool // if true, print a SHA256 hash of the certificate's Raw field
-)
-
-func wrapPrint(text string, indent int) {
-	tabs := ""
-	var tabsSb140 strings.Builder
-	for range indent {
-		tabsSb140.WriteString("\t")
-	}
-	tabs += tabsSb140.String()
-
-	fmt.Fprintf(os.Stdout, tabs+"%s\n", wrap(text, indent))
-}
-
-func displayCert(cert *x509.Certificate) {
-	fmt.Fprintln(os.Stdout, "CERTIFICATE")
-	if showHash {
-		fmt.Fprintln(os.Stdout, wrap(fmt.Sprintf("SHA256: %x", sha256.Sum256(cert.Raw)), 0))
-	}
-	fmt.Fprintln(os.Stdout, wrap("Subject: "+displayName(cert.Subject), 0))
-	fmt.Fprintln(os.Stdout, wrap("Issuer: "+displayName(cert.Issuer), 0))
-	fmt.Fprintf(os.Stdout, "\tSignature algorithm: %s / %s\n", sigAlgoPK(cert.SignatureAlgorithm),
-		sigAlgoHash(cert.SignatureAlgorithm))
-	fmt.Fprintln(os.Stdout, "Details:")
-	wrapPrint("Public key: "+certPublic(cert), 1)
-	fmt.Fprintf(os.Stdout, "\tSerial number: %s\n", cert.SerialNumber)
-
-	if len(cert.AuthorityKeyId) > 0 {
-		fmt.Fprintf(os.Stdout, "\t%s\n", wrap("AKI: "+dumpHex(cert.AuthorityKeyId), 1))
-	}
-	if len(cert.SubjectKeyId) > 0 {
-		fmt.Fprintf(os.Stdout, "\t%s\n", wrap("SKI: "+dumpHex(cert.SubjectKeyId), 1))
-	}
-
-	wrapPrint("Valid from: "+cert.NotBefore.Format(dateFormat), 1)
-	fmt.Fprintf(os.Stdout, "\t     until: %s\n", cert.NotAfter.Format(dateFormat))
-	fmt.Fprintf(os.Stdout, "\tKey usages: %s\n", keyUsages(cert.KeyUsage))
-
-	if len(cert.ExtKeyUsage) > 0 {
-		fmt.Fprintf(os.Stdout, "\tExtended usages: %s\n", extUsage(cert.ExtKeyUsage))
-	}
-
-	showBasicConstraints(cert)
-
-	validNames := make([]string, 0, len(cert.DNSNames)+len(cert.EmailAddresses)+len(cert.IPAddresses))
-	for i := range cert.DNSNames {
-		validNames = append(validNames, "dns:"+cert.DNSNames[i])
-	}
-
-	for i := range cert.EmailAddresses {
-		validNames = append(validNames, "email:"+cert.EmailAddresses[i])
-	}
-
-	for i := range cert.IPAddresses {
-		validNames = append(validNames, "ip:"+cert.IPAddresses[i].String())
-	}
-
-	sans := fmt.Sprintf("SANs (%d): %s\n", len(validNames), strings.Join(validNames, ", "))
-	wrapPrint(sans, 1)
-
-	l := len(cert.IssuingCertificateURL)
-	if l != 0 {
-		var aia string
-		if l == 1 {
-			aia = "AIA"
-		} else {
-			aia = "AIAs"
-		}
-		wrapPrint(fmt.Sprintf("%d %s:", l, aia), 1)
-		for _, url := range cert.IssuingCertificateURL {
-			wrapPrint(url, 2)
-		}
-	}
-
-	l = len(cert.OCSPServer)
-	if l > 0 {
-		title := "OCSP server"
-		if l > 1 {
-			title += "s"
-		}
-		wrapPrint(title+":\n", 1)
-		for _, ocspServer := range cert.OCSPServer {
-			wrapPrint(fmt.Sprintf("- %s\n", ocspServer), 2)
-		}
-	}
+	leafOnly   bool
 }
 
 func main() {
-	var leafOnly bool
-	flag.BoolVar(&showHash, "d", false, "show hashes of raw DER contents")
-	flag.StringVar(&dateFormat, "s", oneTrueDateFormat, "date `format` in Go time format")
-	flag.BoolVar(&leafOnly, "l", false, "only show the leaf certificate")
+	flag.BoolVar(&config.showHash, "d", false, "show hashes of raw DER contents")
+	flag.StringVar(&config.dateFormat, "s", lib.OneTrueDateFormat, "date `format` in Go time format")
+	flag.BoolVar(&config.leafOnly, "l", false, "only show the leaf certificate")
 	flag.Parse()
 
-	opts := &certlib.FetcherOpts{
-		SkipVerify: true,
-		Roots:      nil,
-	}
+	tlsCfg := &tls.Config{InsecureSkipVerify: true} // #nosec G402 - tool intentionally inspects broken TLS
 
 	for _, filename := range flag.Args() {
 		fmt.Fprintf(os.Stdout, "--%s ---%s", filename, "\n")
-		certs, err := certlib.GetCertificateChain(filename, opts)
+		certs, err := lib.GetCertificateChain(filename, tlsCfg)
 		if err != nil {
-			_, _ = lib.Warn(err, "couldn't read certificate")
+			lib.Warn(err, "couldn't read certificate")
 			continue
 		}
 
-		if leafOnly {
-			displayCert(certs[0])
+		if config.leafOnly {
+			dump.DisplayCert(os.Stdout, certs[0])
 			continue
 		}
 
 		for i := range certs {
-			displayCert(certs[i])
+			dump.DisplayCert(os.Stdout, certs[i])
 		}
 	}
 }

cmd/certexpiry/main.go

@@ -2,95 +2,52 @@ package main
 
 import (
 	"crypto/x509"
-	"crypto/x509/pkix"
 	"flag"
 	"fmt"
-	"os"
-	"strings"
-	"time"
 
-	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/verify"
 	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-var warnOnly bool
-var leeway = 2160 * time.Hour // three months
-
-func displayName(name pkix.Name) string {
-	var ns []string
-
-	if name.CommonName != "" {
-		ns = append(ns, name.CommonName)
-	}
-
-	for i := range name.Country {
-		ns = append(ns, fmt.Sprintf("C=%s", name.Country[i]))
-	}
-
-	for i := range name.Organization {
-		ns = append(ns, fmt.Sprintf("O=%s", name.Organization[i]))
-	}
-
-	for i := range name.OrganizationalUnit {
-		ns = append(ns, fmt.Sprintf("OU=%s", name.OrganizationalUnit[i]))
-	}
-
-	for i := range name.Locality {
-		ns = append(ns, fmt.Sprintf("L=%s", name.Locality[i]))
-	}
-
-	for i := range name.Province {
-		ns = append(ns, fmt.Sprintf("ST=%s", name.Province[i]))
-	}
-
-	if len(ns) > 0 {
-		return "/" + strings.Join(ns, "/")
-	}
-
-	die.With("no subject information in root")
-	return ""
-}
-
-func expires(cert *x509.Certificate) time.Duration {
-	return time.Until(cert.NotAfter)
-}
-
-func inDanger(cert *x509.Certificate) bool {
-	return expires(cert) < leeway
-}
-
-func checkCert(cert *x509.Certificate) {
-	warn := inDanger(cert)
-	name := displayName(cert.Subject)
-	name = fmt.Sprintf("%s/SN=%s", name, cert.SerialNumber)
-	expiry := expires(cert)
-	if warnOnly {
-		if warn {
-			fmt.Fprintf(os.Stderr, "%s expires on %s (in %s)\n", name, cert.NotAfter, expiry)
-		}
-	} else {
-		fmt.Printf("%s expires on %s (in %s)\n", name, cert.NotAfter, expiry)
-	}
-}
-
 func main() {
-	opts := &certlib.FetcherOpts{}
+	var (
+		skipVerify bool
+		strictTLS  bool
+		leeway     = verify.DefaultLeeway
+		warnOnly   bool
+	)
 
-	flag.BoolVar(&opts.SkipVerify, "k", false, "skip server verification")
+	lib.StrictTLSFlag(&strictTLS)
+
+	flag.BoolVar(&skipVerify, "k", false, "skip server verification") // #nosec G402
 	flag.BoolVar(&warnOnly, "q", false, "only warn about expiring certs")
 	flag.DurationVar(&leeway, "t", leeway, "warn if certificates are closer than this to expiring")
 	flag.Parse()
 
+	tlsCfg, err := lib.BaselineTLSConfig(skipVerify, strictTLS)
+	die.If(err)
+
 	for _, file := range flag.Args() {
-		certs, err := certlib.GetCertificateChain(file, opts)
+		var certs []*x509.Certificate
+
+		certs, err = lib.GetCertificateChain(file, tlsCfg)
 		if err != nil {
 			_, _ = lib.Warn(err, "while parsing certificates")
 			continue
 		}
 
 		for _, cert := range certs {
-			checkCert(cert)
+			check := verify.NewCertCheck(cert, leeway)
+
+			if warnOnly {
+				if err = check.Err(); err != nil {
+					lib.Warn(err, "certificate is expiring")
+				}
+			} else {
+				fmt.Printf("%s expires on %s (in %s)\n", check.Name(),
+					cert.NotAfter, check.Expiry())
+			}
 		}
 	}
 }

cmd/certser/main.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"strings"
 
-	"git.wntrmute.dev/kyle/goutils/certlib"
 	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
@@ -32,16 +31,23 @@ func serialString(cert *x509.Certificate, mode lib.HexEncodeMode) string {
 }
 
 func main() {
-	opts := &certlib.FetcherOpts{}
+	var skipVerify bool
+	var strictTLS bool
+	lib.StrictTLSFlag(&strictTLS)
 	displayAs := flag.String("d", "int", "display mode (int, hex, uhex)")
 	showExpiry := flag.Bool("e", false, "show expiry date")
-	flag.BoolVar(&opts.SkipVerify, "k", false, "skip server verification")
+	flag.BoolVar(&skipVerify, "k", false, "skip server verification") // #nosec G402
 	flag.Parse()
 
+	tlsCfg, err := lib.BaselineTLSConfig(skipVerify, strictTLS)
+	die.If(err)
+
 	displayMode := parseDisplayMode(*displayAs)
 
 	for _, arg := range flag.Args() {
-		cert, err := certlib.GetCertificate(arg, opts)
+		var cert *x509.Certificate
+
+		cert, err = lib.GetCertificate(arg, tlsCfg)
 		die.If(err)
 
 		fmt.Printf("%s: %s", arg, serialString(cert, displayMode))

cmd/certverify/main.go

@@ -5,33 +5,18 @@ import (
 	"flag"
 	"fmt"
 	"os"
-	"time"
 
 	"git.wntrmute.dev/kyle/goutils/certlib"
-	"git.wntrmute.dev/kyle/goutils/certlib/revoke"
+	"git.wntrmute.dev/kyle/goutils/certlib/verify"
+	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-func printRevocation(cert *x509.Certificate) {
-	remaining := time.Until(cert.NotAfter)
-	fmt.Printf("certificate expires in %s.\n", lib.Duration(remaining))
-
-	revoked, ok := revoke.VerifyCertificate(cert)
-	if !ok {
-		fmt.Fprintf(os.Stderr, "[!] the revocation check failed (failed to determine whether certificate\nwas revoked)")
-		return
-	}
-
-	if revoked {
-		fmt.Fprintf(os.Stderr, "[!] the certificate has been revoked\n")
-		return
-	}
-}
-
 type appConfig struct {
 	caFile, intFile             string
 	forceIntermediateBundle     bool
 	revexp, skipVerify, verbose bool
+	strictTLS                   bool
 }
 
 func parseFlags() appConfig {
@@ -43,107 +28,66 @@ func parseFlags() appConfig {
 	flag.BoolVar(&cfg.skipVerify, "k", false, "skip CA verification")
 	flag.BoolVar(&cfg.revexp, "r", false, "print revocation and expiry information")
 	flag.BoolVar(&cfg.verbose, "v", false, "verbose")
+	lib.StrictTLSFlag(&cfg.strictTLS)
 	flag.Parse()
+
+	if flag.NArg() == 0 {
+		die.With("usage: certverify targets...")
+	}
+
 	return cfg
 }
 
-func loadRoots(caFile string, verbose bool) (*x509.CertPool, error) {
-	if caFile == "" {
-		return x509.SystemCertPool()
-	}
-
-	if verbose {
-		fmt.Println("[+] loading root certificates from", caFile)
-	}
-	return certlib.LoadPEMCertPool(caFile)
-}
-
-func loadIntermediates(intFile string, verbose bool) (*x509.CertPool, error) {
-	if intFile == "" {
-		return x509.NewCertPool(), nil
-	}
-	if verbose {
-		fmt.Println("[+] loading intermediate certificates from", intFile)
-	}
-	// Note: use intFile here (previously used caFile mistakenly)
-	return certlib.LoadPEMCertPool(intFile)
-}
-
-func addBundledIntermediates(chain []*x509.Certificate, pool *x509.CertPool, verbose bool) {
-	for _, intermediate := range chain[1:] {
-		if verbose {
-			fmt.Printf("[+] adding intermediate with SKI %x\n", intermediate.SubjectKeyId)
-		}
-		pool.AddCert(intermediate)
-	}
-}
-
-func verifyCert(cert *x509.Certificate, roots, ints *x509.CertPool) error {
-	opts := x509.VerifyOptions{
-		Intermediates: ints,
-		Roots:         roots,
-		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
-	}
-	_, err := cert.Verify(opts)
-	return err
-}
-
-func run(cfg appConfig) error {
-	roots, err := loadRoots(cfg.caFile, cfg.verbose)
-	if err != nil {
-		return err
-	}
-
-	ints, err := loadIntermediates(cfg.intFile, cfg.verbose)
-	if err != nil {
-		return err
-	}
-
-	if flag.NArg() != 1 {
-		fmt.Fprintf(os.Stderr, "Usage: %s [-ca bundle] [-i bundle] cert", lib.ProgName())
-	}
-
-	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 cfg.revexp {
-		printRevocation(cert)
-	}
-	return nil
-}
-
 func main() {
+	var (
+		roots, ints *x509.CertPool
+		err         error
+		failed      bool
+	)
+
 	cfg := parseFlags()
-	if err := run(cfg); err != nil {
-		fmt.Fprintf(os.Stderr, "%v\n", err)
+
+	opts := &verify.Opts{
+		CheckRevocation:    cfg.revexp,
+		ForceIntermediates: cfg.forceIntermediateBundle,
+		Verbose:            cfg.verbose,
+	}
+
+	if cfg.caFile != "" {
+		if cfg.verbose {
+			fmt.Printf("loading CA certificates from %s\n", cfg.caFile)
+		}
+
+		roots, err = certlib.LoadPEMCertPool(cfg.caFile)
+		die.If(err)
+	}
+
+	if cfg.intFile != "" {
+		if cfg.verbose {
+			fmt.Printf("loading intermediate certificates from %s\n", cfg.intFile)
+		}
+
+		ints, err = certlib.LoadPEMCertPool(cfg.intFile)
+		die.If(err)
+	}
+
+	opts.Config, err = lib.BaselineTLSConfig(cfg.skipVerify, cfg.strictTLS)
+	die.If(err)
+
+	opts.Config.RootCAs = roots
+	opts.Intermediates = ints
+
+	for _, arg := range flag.Args() {
+		_, err = verify.Chain(os.Stdout, arg, opts)
+		if err != nil {
+			lib.Warn(err, "while verifying %s", arg)
+			failed = true
+		} else {
+			fmt.Printf("%s: OK\n", arg)
+		}
+	}
+
+	if failed {
 		os.Exit(1)
 	}
 }

cmd/kgz/README

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

cmd/kgz/main.go

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

cmd/rhash/main.go

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

cmd/ski/main.go

@@ -1,29 +1,19 @@
 package main
 
 import (
-	"bytes"
-	"crypto/ecdsa"
-	"crypto/rsa"
-	"crypto/sha1" // #nosec G505
-	"crypto/x509"
-	"crypto/x509/pkix"
-	"encoding/asn1"
-	"encoding/pem"
+
+	// #nosec G505
+
 	"flag"
 	"fmt"
 	"io"
 	"os"
 
-	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/ski"
 	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-const (
-	keyTypeRSA   = "RSA"
-	keyTypeECDSA = "ECDSA"
-)
-
 func usage(w io.Writer) {
 	fmt.Fprintf(w, `ski: print subject key info for PEM-encoded files
 
@@ -42,117 +32,6 @@ func init() {
 	flag.Usage = func() { usage(os.Stderr) }
 }
 
-func parse(path string) ([]byte, string, string) {
-	data, err := os.ReadFile(path)
-	die.If(err)
-
-	data = bytes.TrimSpace(data)
-	p, rest := pem.Decode(data)
-	if len(rest) > 0 {
-		_, _ = lib.Warnx("trailing data in PEM file")
-	}
-
-	if p == nil {
-		die.With("no PEM data found")
-	}
-
-	data = p.Bytes
-
-	var (
-		public []byte
-		kt     string
-		ft     string
-	)
-
-	switch p.Type {
-	case "PRIVATE KEY", "RSA PRIVATE KEY", "EC PRIVATE KEY":
-		public, kt = parseKey(data)
-		ft = "private key"
-	case "CERTIFICATE":
-		public, kt = parseCertificate(data)
-		ft = "certificate"
-	case "CERTIFICATE REQUEST":
-		public, kt = parseCSR(data)
-		ft = "certificate request"
-	default:
-		die.With("unknown PEM type %s", p.Type)
-	}
-
-	return public, kt, ft
-}
-
-func parseKey(data []byte) ([]byte, string) {
-	priv, err := certlib.ParsePrivateKeyDER(data)
-	if err != nil {
-		die.If(err)
-	}
-
-	var kt string
-	switch priv.Public().(type) {
-	case *rsa.PublicKey:
-		kt = keyTypeRSA
-	case *ecdsa.PublicKey:
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown private key type %T", priv)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(priv.Public())
-	die.If(err)
-
-	return public, kt
-}
-
-func parseCertificate(data []byte) ([]byte, string) {
-	cert, err := x509.ParseCertificate(data)
-	die.If(err)
-
-	pub := cert.PublicKey
-	var kt string
-	switch pub.(type) {
-	case *rsa.PublicKey:
-		kt = keyTypeRSA
-	case *ecdsa.PublicKey:
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown public key type %T", pub)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(pub)
-	die.If(err)
-	return public, kt
-}
-
-func parseCSR(data []byte) ([]byte, string) {
-	// Use certlib to support both PEM and DER and to centralize validation.
-	csr, _, err := certlib.ParseCSR(data)
-	die.If(err)
-
-	pub := csr.PublicKey
-	var kt string
-	switch pub.(type) {
-	case *rsa.PublicKey:
-		kt = keyTypeRSA
-	case *ecdsa.PublicKey:
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown public key type %T", pub)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(pub)
-	die.If(err)
-	return public, kt
-}
-
-func dumpHex(in []byte, mode lib.HexEncodeMode) string {
-	return lib.HexEncode(in, mode)
-}
-
-type subjectPublicKeyInfo struct {
-	Algorithm        pkix.AlgorithmIdentifier
-	SubjectPublicKey asn1.BitString
-}
-
 func main() {
 	var help, shouldMatch bool
 	var displayModeString string
@@ -168,27 +47,22 @@ func main() {
 		os.Exit(0)
 	}
 
-	var ski string
+	var matchSKI string
 	for _, path := range flag.Args() {
-		public, kt, ft := parse(path)
+		keyInfo, err := ski.ParsePEM(path)
+		die.If(err)
 
-		var subPKI subjectPublicKeyInfo
-		_, err := asn1.Unmarshal(public, &subPKI)
-		if err != nil {
-			_, _ = lib.Warn(err, "failed to get subject PKI")
-			continue
+		keySKI, err := keyInfo.SKI(displayMode)
+		die.If(err)
+
+		if matchSKI == "" {
+			matchSKI = keySKI
 		}
 
-		pubHash := sha1.Sum(subPKI.SubjectPublicKey.Bytes) // #nosec G401 this is the standard
-		pubHashString := dumpHex(pubHash[:], displayMode)
-		if ski == "" {
-			ski = pubHashString
-		}
-
-		if shouldMatch && ski != pubHashString {
+		if shouldMatch && matchSKI != keySKI {
 			_, _ = lib.Warnx("%s: SKI mismatch (%s != %s)",
-				path, ski, pubHashString)
+				path, matchSKI, keySKI)
 		}
-		fmt.Printf("%s  %s (%s %s)\n", path, pubHashString, kt, ft)
+		fmt.Printf("%s  %s (%s %s)\n", path, keySKI, keyInfo.KeyType, keyInfo.FileType)
 	}
 }

cmd/stealchain/main.go

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

cmd/tlsinfo/main.go

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

dbg/dbg.go

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

go.mod

@@ -6,7 +6,8 @@ require (
 	github.com/hashicorp/go-syslog v1.0.0
 	github.com/kr/text v0.2.0
 	github.com/pkg/sftp v1.12.0
-	golang.org/x/crypto v0.44.0
+	golang.org/x/crypto v0.39.0
+	golang.org/x/net v0.38.0
 	golang.org/x/sys v0.38.0
 	gopkg.in/yaml.v2 v2.4.0
 )

go.sum

@@ -27,13 +27,19 @@ github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.39.0 h1:SHs+kF4LP+f+p14esP5jAoDpHU8Gu/v9lFRK6IT5imM=
+golang.org/x/crypto v0.39.0/go.mod h1:L+Xg3Wf6HoL4Bn4238Z6ft6KfEpN0tJGo53AAPC632U=
 golang.org/x/crypto v0.44.0 h1:A97SsFvM3AIwEEmTBiaxPPTYpDC47w720rdiiUvgoAU=
 golang.org/x/crypto v0.44.0/go.mod h1:013i+Nw79BMiQiMsOPcVCB5ZIJbYkerPrGnOa00tvmc=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.38.0 h1:vRMAPTMaeGqVhG5QyLJHqNDwecKTomGeqbnfZyKlBI8=
+golang.org/x/net v0.38.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
+golang.org/x/net v0.46.0/go.mod h1:Q9BGdFy1y4nkUwiLvT5qtyhAnEHgnQ/zd8PfU6nc210=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
 golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/term v0.32.0 h1:DR4lr0TjUs3epypdhTOkMmuF5CDFJ/8pOnbzMZPQ7bg=
 golang.org/x/term v0.37.0 h1:8EGAD0qCmHYZg6J17DvsMy9/wJ7/D/4pV/wfnld5lTU=
 golang.org/x/term v0.37.0/go.mod h1:5pB4lxRNYYVZuTLmy8oR2BH8dflOR+IbTYFD8fi3254=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

lib/defs.go

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

lib/dialer.go

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

lib/fetch.go

@@ -1,25 +1,21 @@
-package certlib
+package lib
 
 import (
 	"context"
 	"crypto/tls"
 	"crypto/x509"
-	"errors"
 	"fmt"
 	"io"
 	"net"
 	"os"
 
+	"git.wntrmute.dev/kyle/goutils/certlib"
 	"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
-}
+// Note: Previously this package exposed a FetcherOpts type. It has been
+// refactored to use *tls.Config directly for configuring TLS behavior.
 
 // Fetcher is an interface for fetching certificates from a remote source. It
 // currently supports fetching from a server or a file.
@@ -65,29 +61,20 @@ func ParseServer(host string) (*ServerFetcher, error) {
 }
 
 func (sf *ServerFetcher) String() string {
-	return fmt.Sprintf("tls://%s", net.JoinHostPort(sf.host, lib.Itoa(sf.port, -1)))
+	return fmt.Sprintf("tls://%s", net.JoinHostPort(sf.host, 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,
+	opts := DialerOpts{
+		TLSConfig: &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)
+	conn, err := DialTLS(context.Background(), net.JoinHostPort(sf.host, Itoa(sf.port, -1)), opts)
 	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")
+		return nil, fmt.Errorf("failed to dial server: %w", err)
 	}
 	defer conn.Close()
 
@@ -125,10 +112,10 @@ func (ff *FileFetcher) GetChain() ([]*x509.Certificate, error) {
 			return nil, fmt.Errorf("failed to read from stdin: %w", err)
 		}
 
-		return ParseCertificatesPEM(certData)
+		return certlib.ParseCertificatesPEM(certData)
 	}
 
-	certs, err := LoadCertificates(ff.path)
+	certs, err := certlib.LoadCertificates(ff.path)
 	if err != nil {
 		return nil, fmt.Errorf("failed to load chain: %w", err)
 	}
@@ -146,7 +133,10 @@ func (ff *FileFetcher) Get() (*x509.Certificate, error) {
 }
 
 // GetCertificateChain fetches a certificate chain from a remote source.
-func GetCertificateChain(spec string, opts *FetcherOpts) ([]*x509.Certificate, error) {
+// If cfg is non-nil and spec refers to a TLS server, the provided TLS
+// configuration will be used to control verification behavior (e.g.,
+// InsecureSkipVerify, RootCAs).
+func GetCertificateChain(spec string, cfg *tls.Config) ([]*x509.Certificate, error) {
 	if fileutil.FileDoesExist(spec) {
 		return NewFileFetcher(spec).GetChain()
 	}
@@ -156,17 +146,17 @@ func GetCertificateChain(spec string, opts *FetcherOpts) ([]*x509.Certificate, e
 		return nil, err
 	}
 
-	if opts != nil {
-		fetcher.insecure = opts.SkipVerify
-		fetcher.roots = opts.Roots
+	if cfg != nil {
+		fetcher.insecure = cfg.InsecureSkipVerify
+		fetcher.roots = cfg.RootCAs
 	}
 
 	return fetcher.GetChain()
 }
 
 // GetCertificate fetches the first certificate from a certificate chain.
-func GetCertificate(spec string, opts *FetcherOpts) (*x509.Certificate, error) {
-	certs, err := GetCertificateChain(spec, opts)
+func GetCertificate(spec string, cfg *tls.Config) (*x509.Certificate, error) {
+	certs, err := GetCertificateChain(spec, cfg)
 	if err != nil {
 		return nil, err
 	}

lib/lib.go

@@ -1,4 +1,3 @@
-// Package lib contains functions useful for most programs.
 package lib
 
 import (

release-docker.sh

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