Update CHANGELOG for v1.14.3,

CHANGELOG

@@ -1,5 +1,15 @@
 CHANGELOG
 
+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:

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)
+		}
+	}
+}

cmd/certdump/main.go

@@ -2,353 +2,25 @@
 package main
 
 import (
-	"crypto/dsa"
-	"crypto/ecdsa"
-	"crypto/elliptic"
-	"crypto/rsa"
-	"crypto/sha256"
 	"crypto/tls"
-	"crypto/x509"
-	"crypto/x509/pkix"
 	"flag"
 	"fmt"
 	"os"
-	"sort"
-	"strings"
-
-	"github.com/kr/text"
 
+	"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()
 
 	tlsCfg := &tls.Config{InsecureSkipVerify: true} // #nosec G402 - tool intentionally inspects broken TLS
@@ -357,17 +29,17 @@ func main() {
 		fmt.Fprintf(os.Stdout, "--%s ---%s", filename, "\n")
 		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/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 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 +3,122 @@ package main
 import (
 	"compress/flate"
 	"compress/gzip"
+	"encoding/asn1"
+	"encoding/binary"
 	"flag"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"strings"
+
+	goutilslib "git.wntrmute.dev/kyle/goutils/lib"
+	"golang.org/x/sys/unix"
 )
 
 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]
+	extra := make([]byte, 4+len(payload))
+	extra[0] = kgzExtraID[0]
+	extra[1] = kgzExtraID[1]
+	binary.LittleEndian.PutUint16(extra[2:], uint16(len(payload)))
+	copy(extra[4:], payload)
+	return extra
+}
+
+// parseKGExtra scans a gzip Extra blob and returns kgz metadata if present.
+func parseKGExtra(extra []byte) (uid, gid, mode uint32, ctimeS int64, ctimeNs int32, ok 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
+			}
+			return uint32(s.UID), uint32(s.GID), uint32(s.Mode), s.CTimeSec, s.CTimeNSec, true
+		}
+		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 +129,27 @@ 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 {
+		uid := uint32(st.Uid)
+		gid := uint32(st.Gid)
+		if setUID >= 0 {
+			uid = uint32(setUID)
+		}
+		if setGID >= 0 {
+			gid = uint32(setGID)
+		}
+		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 = int32(ft.Changed.Nanosecond())
+		}
+		gzipCompressor.Extra = buildKGExtra(uid, gid, mode, cts, ctns)
+	}
 	defer gzipCompressor.Close()
 
 	_, err = io.Copy(gzipCompressor, sourceFile)
@@ -40,7 +160,7 @@ 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 +199,40 @@ 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 +291,19 @@ 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 +323,15 @@ 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 +341,13 @@ 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)
+	}
 }

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"
+)