Files
goutils/certlib/dump/dump.go
2025-11-19 01:47:42 -08:00

340 lines
8.6 KiB
Go

// 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)
}
}
}