1// Copyright 2009 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.45// Package x509 implements a subset of the X.509 standard.6//7// It allows parsing and generating certificates, certificate signing8// requests, certificate revocation lists, and encoded public and private keys.9// It provides a certificate verifier, complete with a chain builder.10//11// The package targets the X.509 technical profile defined by the IETF (RFC12// 2459/3280/5280), and as further restricted by the CA/Browser Forum Baseline13// Requirements. There is minimal support for features outside of these14// profiles, as the primary goal of the package is to provide compatibility15// with the publicly trusted TLS certificate ecosystem and its policies and16// constraints.17//18// On macOS and Windows, certificate verification is handled by system APIs, but19// the package aims to apply consistent validation rules across operating20// systems.21package x5092223import (24	"bytes"25	"crypto"26	"crypto/ecdh"27	"crypto/ecdsa"28	"crypto/ed25519"29	"crypto/elliptic"30	"crypto/fips140"31	"crypto/mldsa"32	"crypto/mlkem"33	"crypto/rsa"34	"crypto/sha1"35	"crypto/sha256"36	"crypto/x509/pkix"37	"encoding/asn1"38	"encoding/pem"39	"errors"40	"fmt"41	"internal/godebug"42	"io"43	"math/big"44	"net"45	"net/url"46	"strconv"47	"time"48	"unicode"4950	// Explicitly import these for their crypto.RegisterHash init side-effects.51	// Keep these as blank imports, even if they're imported above.52	_ "crypto/sha1"53	_ "crypto/sha256"54	_ "crypto/sha512"5556	"golang.org/x/crypto/cryptobyte"57	cryptobyte_asn1 "golang.org/x/crypto/cryptobyte/asn1"58)5960// pkixPublicKey reflects a PKIX public key structure. See SubjectPublicKeyInfo61// in RFC 3280.62type pkixPublicKey struct {63	Algo      pkix.AlgorithmIdentifier64	BitString asn1.BitString65}6667// ParsePKIXPublicKey parses a public key in PKIX, ASN.1 DER form. The encoded68// public key is a SubjectPublicKeyInfo structure (see RFC 5280, Section 4.1).69//70// It returns a *[rsa.PublicKey], *[dsa.PublicKey], *[ecdsa.PublicKey],71// [ed25519.PublicKey] (not a pointer), *[mldsa.PublicKey], *[ecdh.PublicKey]72// (for X25519), *[mlkem.EncapsulationKey768], or *[mlkem.EncapsulationKey1024].73// More types might be supported in the future.74//75// This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".76func ParsePKIXPublicKey(derBytes []byte) (pub any, err error) {77	var pki publicKeyInfo78	if rest, err := asn1.Unmarshal(derBytes, &pki); err != nil {79		if _, err := asn1.Unmarshal(derBytes, &pkcs1PublicKey{}); err == nil {80			return nil, errors.New("x509: failed to parse public key (use ParsePKCS1PublicKey instead for this key format)")81		}82		return nil, err83	} else if len(rest) != 0 {84		return nil, errors.New("x509: trailing data after ASN.1 of public-key")85	}86	return parsePublicKey(&pki)87}8889func marshalPublicKey(pub any) (publicKeyBytes []byte, publicKeyAlgorithm pkix.AlgorithmIdentifier, err error) {90	switch pub := pub.(type) {91	case *rsa.PublicKey:92		publicKeyBytes, err = asn1.Marshal(pkcs1PublicKey{93			N: pub.N,94			E: pub.E,95		})96		if err != nil {97			return nil, pkix.AlgorithmIdentifier{}, err98		}99		publicKeyAlgorithm.Algorithm = oidPublicKeyRSA100		// This is a NULL parameters value which is required by101		// RFC 3279, Section 2.3.1.102		publicKeyAlgorithm.Parameters = asn1.NullRawValue103	case *ecdsa.PublicKey:104		oid, ok := oidFromNamedCurve(pub.Curve)105		if !ok {106			return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")107		}108		publicKeyBytes, err = pub.Bytes()109		if err != nil {110			return nil, pkix.AlgorithmIdentifier{}, err111		}112		publicKeyAlgorithm.Algorithm = oidPublicKeyECDSA113		var paramBytes []byte114		paramBytes, err = asn1.Marshal(oid)115		if err != nil {116			return117		}118		publicKeyAlgorithm.Parameters.FullBytes = paramBytes119	case ed25519.PublicKey:120		publicKeyBytes = pub121		publicKeyAlgorithm.Algorithm = oidPublicKeyEd25519122	case *mldsa.PublicKey:123		oid, ok := oidFromMLDSAParameters(pub.Parameters())124		if !ok {125			return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported ML-DSA parameters")126		}127		publicKeyBytes = pub.Bytes()128		publicKeyAlgorithm.Algorithm = oid129	case *ecdh.PublicKey:130		publicKeyBytes = pub.Bytes()131		if pub.Curve() == ecdh.X25519() {132			publicKeyAlgorithm.Algorithm = oidPublicKeyX25519133		} else {134			oid, ok := oidFromECDHCurve(pub.Curve())135			if !ok {136				return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")137			}138			publicKeyAlgorithm.Algorithm = oidPublicKeyECDSA139			var paramBytes []byte140			paramBytes, err = asn1.Marshal(oid)141			if err != nil {142				return143			}144			publicKeyAlgorithm.Parameters.FullBytes = paramBytes145		}146	case *mlkem.EncapsulationKey768:147		publicKeyBytes = pub.Bytes()148		publicKeyAlgorithm.Algorithm = oidPublicKeyMLKEM768149	case *mlkem.EncapsulationKey1024:150		publicKeyBytes = pub.Bytes()151		publicKeyAlgorithm.Algorithm = oidPublicKeyMLKEM1024152	default:153		return nil, pkix.AlgorithmIdentifier{}, fmt.Errorf("x509: unsupported public key type: %T", pub)154	}155156	return publicKeyBytes, publicKeyAlgorithm, nil157}158159// MarshalPKIXPublicKey converts a public key to PKIX, ASN.1 DER form.160// The encoded public key is a SubjectPublicKeyInfo structure161// (see RFC 5280, Section 4.1).162//163// The following key types are currently supported: *[rsa.PublicKey],164// *[ecdsa.PublicKey], [ed25519.PublicKey] (not a pointer), *[mldsa.PublicKey],165// *[ecdh.PublicKey], *[mlkem.EncapsulationKey768], and166// *[mlkem.EncapsulationKey1024]. Unsupported key types result in an error.167//168// This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".169func MarshalPKIXPublicKey(pub any) ([]byte, error) {170	var publicKeyBytes []byte171	var publicKeyAlgorithm pkix.AlgorithmIdentifier172	var err error173174	if publicKeyBytes, publicKeyAlgorithm, err = marshalPublicKey(pub); err != nil {175		return nil, err176	}177178	pkix := pkixPublicKey{179		Algo: publicKeyAlgorithm,180		BitString: asn1.BitString{181			Bytes:     publicKeyBytes,182			BitLength: 8 * len(publicKeyBytes),183		},184	}185186	ret, _ := asn1.Marshal(pkix)187	return ret, nil188}189190// These structures reflect the ASN.1 structure of X.509 certificates.:191192type certificate struct {193	TBSCertificate     tbsCertificate194	SignatureAlgorithm pkix.AlgorithmIdentifier195	SignatureValue     asn1.BitString196}197198type tbsCertificate struct {199	Raw                asn1.RawContent200	Version            int `asn1:"optional,explicit,default:0,tag:0"`201	SerialNumber       *big.Int202	SignatureAlgorithm pkix.AlgorithmIdentifier203	Issuer             asn1.RawValue204	Validity           validity205	Subject            asn1.RawValue206	PublicKey          publicKeyInfo207	UniqueId           asn1.BitString   `asn1:"optional,tag:1"`208	SubjectUniqueId    asn1.BitString   `asn1:"optional,tag:2"`209	Extensions         []pkix.Extension `asn1:"omitempty,optional,explicit,tag:3"`210}211212type dsaAlgorithmParameters struct {213	P, Q, G *big.Int214}215216type validity struct {217	NotBefore, NotAfter time.Time218}219220type publicKeyInfo struct {221	Raw       asn1.RawContent222	Algorithm pkix.AlgorithmIdentifier223	PublicKey asn1.BitString224}225226// RFC 5280,  4.2.1.1227type authKeyId struct {228	Id []byte `asn1:"optional,tag:0"`229}230231type SignatureAlgorithm int232233const (234	UnknownSignatureAlgorithm SignatureAlgorithm = iota235236	MD2WithRSA  // Unsupported.237	MD5WithRSA  // Only supported for signing, not verification.238	SHA1WithRSA // Only supported for signing, and verification of CRLs, CSRs, and OCSP responses.239	SHA256WithRSA240	SHA384WithRSA241	SHA512WithRSA242	DSAWithSHA1   // Unsupported.243	DSAWithSHA256 // Unsupported.244	ECDSAWithSHA1 // Only supported for signing, and verification of CRLs, CSRs, and OCSP responses.245	ECDSAWithSHA256246	ECDSAWithSHA384247	ECDSAWithSHA512248	SHA256WithRSAPSS249	SHA384WithRSAPSS250	SHA512WithRSAPSS251	PureEd25519252	MLDSA44253	MLDSA65254	MLDSA87255)256257func (algo SignatureAlgorithm) isRSAPSS() bool {258	for _, details := range signatureAlgorithmDetails {259		if details.algo == algo {260			return details.isRSAPSS261		}262	}263	return false264}265266func (algo SignatureAlgorithm) hashFunc() crypto.Hash {267	for _, details := range signatureAlgorithmDetails {268		if details.algo == algo {269			return details.hash270		}271	}272	return crypto.Hash(0)273}274275func (algo SignatureAlgorithm) String() string {276	for _, details := range signatureAlgorithmDetails {277		if details.algo == algo {278			return details.name279		}280	}281	return strconv.Itoa(int(algo))282}283284type PublicKeyAlgorithm int285286const (287	UnknownPublicKeyAlgorithm PublicKeyAlgorithm = iota288	RSA289	DSA // Only supported for parsing.290	ECDSA291	Ed25519292	MLDSA293)294295var publicKeyAlgoName = [...]string{296	RSA:     "RSA",297	DSA:     "DSA",298	ECDSA:   "ECDSA",299	Ed25519: "Ed25519",300	MLDSA:   "ML-DSA",301}302303func (algo PublicKeyAlgorithm) String() string {304	if 0 < algo && int(algo) < len(publicKeyAlgoName) {305		return publicKeyAlgoName[algo]306	}307	return strconv.Itoa(int(algo))308}309310// OIDs for signature algorithms311//312//	pkcs-1 OBJECT IDENTIFIER ::= {313//		iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 1 }314//315// RFC 3279 2.2.1 RSA Signature Algorithms316//317//	md5WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 4 }318//319//	sha-1WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 5 }320//321//	dsaWithSha1 OBJECT IDENTIFIER ::= {322//		iso(1) member-body(2) us(840) x9-57(10040) x9cm(4) 3 }323//324// RFC 3279 2.2.3 ECDSA Signature Algorithm325//326//	ecdsa-with-SHA1 OBJECT IDENTIFIER ::= {327//		iso(1) member-body(2) us(840) ansi-x962(10045)328//		signatures(4) ecdsa-with-SHA1(1)}329//330// RFC 4055 5 PKCS #1 Version 1.5331//332//	sha256WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 11 }333//334//	sha384WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 12 }335//336//	sha512WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 13 }337//338// RFC 5758 3.1 DSA Signature Algorithms339//340//	dsaWithSha256 OBJECT IDENTIFIER ::= {341//		joint-iso-ccitt(2) country(16) us(840) organization(1) gov(101)342//		csor(3) algorithms(4) id-dsa-with-sha2(3) 2}343//344// RFC 5758 3.2 ECDSA Signature Algorithm345//346//	ecdsa-with-SHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)347//		us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 2 }348//349//	ecdsa-with-SHA384 OBJECT IDENTIFIER ::= { iso(1) member-body(2)350//		us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 3 }351//352//	ecdsa-with-SHA512 OBJECT IDENTIFIER ::= { iso(1) member-body(2)353//		us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 4 }354//355// RFC 8410 3 Curve25519 and Curve448 Algorithm Identifiers356//357//	id-Ed25519   OBJECT IDENTIFIER ::= { 1 3 101 112 }358var (359	oidSignatureMD5WithRSA      = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 4}360	oidSignatureSHA1WithRSA     = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}361	oidSignatureSHA256WithRSA   = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 11}362	oidSignatureSHA384WithRSA   = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 12}363	oidSignatureSHA512WithRSA   = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 13}364	oidSignatureRSAPSS          = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 10}365	oidSignatureDSAWithSHA1     = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 3}366	oidSignatureDSAWithSHA256   = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 3, 2}367	oidSignatureECDSAWithSHA1   = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 1}368	oidSignatureECDSAWithSHA256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 2}369	oidSignatureECDSAWithSHA384 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 3}370	oidSignatureECDSAWithSHA512 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 4}371	oidSignatureEd25519         = asn1.ObjectIdentifier{1, 3, 101, 112}372373	oidSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 1}374	oidSHA384 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 2}375	oidSHA512 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 3}376377	oidMGF1 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 8}378379	// oidISOSignatureSHA1WithRSA means the same as oidSignatureSHA1WithRSA380	// but it's specified by ISO. Microsoft's makecert.exe has been known381	// to produce certificates with this OID.382	oidISOSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 3, 14, 3, 2, 29}383)384385var signatureAlgorithmDetails = []struct {386	algo       SignatureAlgorithm387	name       string388	oid        asn1.ObjectIdentifier389	params     asn1.RawValue390	pubKeyAlgo PublicKeyAlgorithm391	hash       crypto.Hash392	isRSAPSS   bool393}{394	{MD5WithRSA, "MD5-RSA", oidSignatureMD5WithRSA, asn1.NullRawValue, RSA, crypto.MD5, false},395	{SHA1WithRSA, "SHA1-RSA", oidSignatureSHA1WithRSA, asn1.NullRawValue, RSA, crypto.SHA1, false},396	{SHA1WithRSA, "SHA1-RSA", oidISOSignatureSHA1WithRSA, asn1.NullRawValue, RSA, crypto.SHA1, false},397	{SHA256WithRSA, "SHA256-RSA", oidSignatureSHA256WithRSA, asn1.NullRawValue, RSA, crypto.SHA256, false},398	{SHA384WithRSA, "SHA384-RSA", oidSignatureSHA384WithRSA, asn1.NullRawValue, RSA, crypto.SHA384, false},399	{SHA512WithRSA, "SHA512-RSA", oidSignatureSHA512WithRSA, asn1.NullRawValue, RSA, crypto.SHA512, false},400	{SHA256WithRSAPSS, "SHA256-RSAPSS", oidSignatureRSAPSS, pssParametersSHA256, RSA, crypto.SHA256, true},401	{SHA384WithRSAPSS, "SHA384-RSAPSS", oidSignatureRSAPSS, pssParametersSHA384, RSA, crypto.SHA384, true},402	{SHA512WithRSAPSS, "SHA512-RSAPSS", oidSignatureRSAPSS, pssParametersSHA512, RSA, crypto.SHA512, true},403	{DSAWithSHA1, "DSA-SHA1", oidSignatureDSAWithSHA1, emptyRawValue, DSA, crypto.SHA1, false},404	{DSAWithSHA256, "DSA-SHA256", oidSignatureDSAWithSHA256, emptyRawValue, DSA, crypto.SHA256, false},405	{ECDSAWithSHA1, "ECDSA-SHA1", oidSignatureECDSAWithSHA1, emptyRawValue, ECDSA, crypto.SHA1, false},406	{ECDSAWithSHA256, "ECDSA-SHA256", oidSignatureECDSAWithSHA256, emptyRawValue, ECDSA, crypto.SHA256, false},407	{ECDSAWithSHA384, "ECDSA-SHA384", oidSignatureECDSAWithSHA384, emptyRawValue, ECDSA, crypto.SHA384, false},408	{ECDSAWithSHA512, "ECDSA-SHA512", oidSignatureECDSAWithSHA512, emptyRawValue, ECDSA, crypto.SHA512, false},409	{PureEd25519, "Ed25519", oidSignatureEd25519, emptyRawValue, Ed25519, crypto.Hash(0) /* no pre-hashing */, false},410	{MLDSA44, "ML-DSA-44", oidPublicKeyMLDSA44, emptyRawValue, MLDSA, crypto.Hash(0) /* no pre-hashing */, false},411	{MLDSA65, "ML-DSA-65", oidPublicKeyMLDSA65, emptyRawValue, MLDSA, crypto.Hash(0) /* no pre-hashing */, false},412	{MLDSA87, "ML-DSA-87", oidPublicKeyMLDSA87, emptyRawValue, MLDSA, crypto.Hash(0) /* no pre-hashing */, false},413}414415var emptyRawValue = asn1.RawValue{}416417// DER encoded RSA PSS parameters for the418// SHA256, SHA384, and SHA512 hashes as defined in RFC 3447, Appendix A.2.3.419// The parameters contain the following values:420//   - hashAlgorithm contains the associated hash identifier with NULL parameters421//   - maskGenAlgorithm always contains the default mgf1SHA1 identifier422//   - saltLength contains the length of the associated hash423//   - trailerField always contains the default trailerFieldBC value424var (425	pssParametersSHA256 = asn1.RawValue{FullBytes: []byte{48, 52, 160, 15, 48, 13, 6, 9, 96, 134, 72, 1, 101, 3, 4, 2, 1, 5, 0, 161, 28, 48, 26, 6, 9, 42, 134, 72, 134, 247, 13, 1, 1, 8, 48, 13, 6, 9, 96, 134, 72, 1, 101, 3, 4, 2, 1, 5, 0, 162, 3, 2, 1, 32}}426	pssParametersSHA384 = asn1.RawValue{FullBytes: []byte{48, 52, 160, 15, 48, 13, 6, 9, 96, 134, 72, 1, 101, 3, 4, 2, 2, 5, 0, 161, 28, 48, 26, 6, 9, 42, 134, 72, 134, 247, 13, 1, 1, 8, 48, 13, 6, 9, 96, 134, 72, 1, 101, 3, 4, 2, 2, 5, 0, 162, 3, 2, 1, 48}}427	pssParametersSHA512 = asn1.RawValue{FullBytes: []byte{48, 52, 160, 15, 48, 13, 6, 9, 96, 134, 72, 1, 101, 3, 4, 2, 3, 5, 0, 161, 28, 48, 26, 6, 9, 42, 134, 72, 134, 247, 13, 1, 1, 8, 48, 13, 6, 9, 96, 134, 72, 1, 101, 3, 4, 2, 3, 5, 0, 162, 3, 2, 1, 64}}428)429430// pssParameters reflects the parameters in an AlgorithmIdentifier that431// specifies RSA PSS. See RFC 3447, Appendix A.2.3.432type pssParameters struct {433	// The following three fields are not marked as434	// optional because the default values specify SHA-1,435	// which is no longer suitable for use in signatures.436	Hash         pkix.AlgorithmIdentifier `asn1:"explicit,tag:0"`437	MGF          pkix.AlgorithmIdentifier `asn1:"explicit,tag:1"`438	SaltLength   int                      `asn1:"explicit,tag:2"`439	TrailerField int                      `asn1:"optional,explicit,tag:3,default:1"`440}441442func getSignatureAlgorithmFromAI(ai pkix.AlgorithmIdentifier) SignatureAlgorithm {443	if ai.Algorithm.Equal(oidSignatureEd25519) ||444		ai.Algorithm.Equal(oidPublicKeyMLDSA44) ||445		ai.Algorithm.Equal(oidPublicKeyMLDSA65) ||446		ai.Algorithm.Equal(oidPublicKeyMLDSA87) {447		// RFC 8410, Section 3448		// > For all of the OIDs, the parameters MUST be absent.449		// RFC 9881, Section 2450		// > The contents of the parameters component for each algorithm MUST be absent.451		if len(ai.Parameters.FullBytes) != 0 {452			return UnknownSignatureAlgorithm453		}454	}455456	if !ai.Algorithm.Equal(oidSignatureRSAPSS) {457		for _, details := range signatureAlgorithmDetails {458			if ai.Algorithm.Equal(details.oid) {459				return details.algo460			}461		}462		return UnknownSignatureAlgorithm463	}464465	// RSA PSS is special because it encodes important parameters466	// in the Parameters.467468	var params pssParameters469	if _, err := asn1.Unmarshal(ai.Parameters.FullBytes, &params); err != nil {470		return UnknownSignatureAlgorithm471	}472473	var mgf1HashFunc pkix.AlgorithmIdentifier474	if _, err := asn1.Unmarshal(params.MGF.Parameters.FullBytes, &mgf1HashFunc); err != nil {475		return UnknownSignatureAlgorithm476	}477478	// PSS is greatly overburdened with options. This code forces them into479	// three buckets by requiring that the MGF1 hash function always match the480	// message hash function (as recommended in RFC 3447, Section 8.1), that the481	// salt length matches the hash length, and that the trailer field has the482	// default value.483	if (len(params.Hash.Parameters.FullBytes) != 0 && !bytes.Equal(params.Hash.Parameters.FullBytes, asn1.NullBytes)) ||484		!params.MGF.Algorithm.Equal(oidMGF1) ||485		!mgf1HashFunc.Algorithm.Equal(params.Hash.Algorithm) ||486		(len(mgf1HashFunc.Parameters.FullBytes) != 0 && !bytes.Equal(mgf1HashFunc.Parameters.FullBytes, asn1.NullBytes)) ||487		params.TrailerField != 1 {488		return UnknownSignatureAlgorithm489	}490491	switch {492	case params.Hash.Algorithm.Equal(oidSHA256) && params.SaltLength == 32:493		return SHA256WithRSAPSS494	case params.Hash.Algorithm.Equal(oidSHA384) && params.SaltLength == 48:495		return SHA384WithRSAPSS496	case params.Hash.Algorithm.Equal(oidSHA512) && params.SaltLength == 64:497		return SHA512WithRSAPSS498	}499500	return UnknownSignatureAlgorithm501}502503var (504	// RFC 3279, 2.3 Public Key Algorithms505	//506	//	pkcs-1 OBJECT IDENTIFIER ::== { iso(1) member-body(2) us(840)507	//		rsadsi(113549) pkcs(1) 1 }508	//509	// rsaEncryption OBJECT IDENTIFIER ::== { pkcs1-1 1 }510	//511	//	id-dsa OBJECT IDENTIFIER ::== { iso(1) member-body(2) us(840)512	//		x9-57(10040) x9cm(4) 1 }513	oidPublicKeyRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}514	oidPublicKeyDSA = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 1}515	// RFC 5480, 2.1.1 Unrestricted Algorithm Identifier and Parameters516	//517	//	id-ecPublicKey OBJECT IDENTIFIER ::= {518	//		iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 }519	oidPublicKeyECDSA = asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}520	// RFC 8410, Section 3521	//522	//	id-X25519    OBJECT IDENTIFIER ::= { 1 3 101 110 }523	//	id-Ed25519   OBJECT IDENTIFIER ::= { 1 3 101 112 }524	oidPublicKeyX25519  = asn1.ObjectIdentifier{1, 3, 101, 110}525	oidPublicKeyEd25519 = asn1.ObjectIdentifier{1, 3, 101, 112}526	// RFC 9881, Section 2527	//528	//	id-ml-dsa-44 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)529	//		country(16) us(840) organization(1) gov(101) csor(3)530	//		nistAlgorithm(4) sigAlgs(3) id-ml-dsa-44(17) }531	//532	//	id-ml-dsa-65 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)533	//		country(16) us(840) organization(1) gov(101) csor(3)534	//		nistAlgorithm(4) sigAlgs(3) id-ml-dsa-65(18) }535	//536	//	id-ml-dsa-87 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)537	//		country(16) us(840) organization(1) gov(101) csor(3)538	//		nistAlgorithm(4) sigAlgs(3) id-ml-dsa-87(19) }539	oidPublicKeyMLDSA44 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 3, 17}540	oidPublicKeyMLDSA65 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 3, 18}541	oidPublicKeyMLDSA87 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 3, 19}542	// RFC 9935, Section 3543	//544	//	id-alg-ml-kem-768  OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)545	//		country(16) us(840) organization(1) gov(101) csor(3)546	//		nistAlgorithm(4) kems(4) id-alg-ml-kem-768(2) }547	//548	//	id-alg-ml-kem-1024 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)549	//		country(16) us(840) organization(1) gov(101) csor(3)550	//		nistAlgorithm(4) kems(4) id-alg-ml-kem-1024(3) }551	oidPublicKeyMLKEM768  = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 4, 2}552	oidPublicKeyMLKEM1024 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 4, 3}553)554555// getPublicKeyAlgorithmFromOID returns the exposed PublicKeyAlgorithm556// identifier for public key types supported in certificates and CSRs. Marshal557// and Parse functions may support a different set of public key types.558func getPublicKeyAlgorithmFromOID(oid asn1.ObjectIdentifier) PublicKeyAlgorithm {559	switch {560	case oid.Equal(oidPublicKeyRSA):561		return RSA562	case oid.Equal(oidPublicKeyDSA):563		return DSA564	case oid.Equal(oidPublicKeyECDSA):565		return ECDSA566	case oid.Equal(oidPublicKeyEd25519):567		return Ed25519568	case oid.Equal(oidPublicKeyMLDSA44),569		oid.Equal(oidPublicKeyMLDSA65),570		oid.Equal(oidPublicKeyMLDSA87):571		// ML-DSA is not available in FIPS 140-3 module v1.0.0.572		if fips140.Version() == "v1.0.0" {573			return UnknownPublicKeyAlgorithm574		}575		return MLDSA576	}577	return UnknownPublicKeyAlgorithm578}579580// RFC 5480, 2.1.1.1. Named Curve581//582//	secp224r1 OBJECT IDENTIFIER ::= {583//	  iso(1) identified-organization(3) certicom(132) curve(0) 33 }584//585//	secp256r1 OBJECT IDENTIFIER ::= {586//	  iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3)587//	  prime(1) 7 }588//589//	secp384r1 OBJECT IDENTIFIER ::= {590//	  iso(1) identified-organization(3) certicom(132) curve(0) 34 }591//592//	secp521r1 OBJECT IDENTIFIER ::= {593//	  iso(1) identified-organization(3) certicom(132) curve(0) 35 }594//595// NB: secp256r1 is equivalent to prime256v1596var (597	oidNamedCurveP224 = asn1.ObjectIdentifier{1, 3, 132, 0, 33}598	oidNamedCurveP256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 3, 1, 7}599	oidNamedCurveP384 = asn1.ObjectIdentifier{1, 3, 132, 0, 34}600	oidNamedCurveP521 = asn1.ObjectIdentifier{1, 3, 132, 0, 35}601)602603func namedCurveFromOID(oid asn1.ObjectIdentifier) elliptic.Curve {604	switch {605	case oid.Equal(oidNamedCurveP224):606		return elliptic.P224()607	case oid.Equal(oidNamedCurveP256):608		return elliptic.P256()609	case oid.Equal(oidNamedCurveP384):610		return elliptic.P384()611	case oid.Equal(oidNamedCurveP521):612		return elliptic.P521()613	}614	return nil615}616617func oidFromNamedCurve(curve elliptic.Curve) (asn1.ObjectIdentifier, bool) {618	switch curve {619	case elliptic.P224():620		return oidNamedCurveP224, true621	case elliptic.P256():622		return oidNamedCurveP256, true623	case elliptic.P384():624		return oidNamedCurveP384, true625	case elliptic.P521():626		return oidNamedCurveP521, true627	}628629	return nil, false630}631632func oidFromECDHCurve(curve ecdh.Curve) (asn1.ObjectIdentifier, bool) {633	switch curve {634	case ecdh.X25519():635		return oidPublicKeyX25519, true636	case ecdh.P256():637		return oidNamedCurveP256, true638	case ecdh.P384():639		return oidNamedCurveP384, true640	case ecdh.P521():641		return oidNamedCurveP521, true642	}643644	return nil, false645}646647func mldsaParametersFromOID(oid asn1.ObjectIdentifier) (mldsa.Parameters, bool) {648	switch {649	case oid.Equal(oidPublicKeyMLDSA44):650		return mldsa.MLDSA44(), true651	case oid.Equal(oidPublicKeyMLDSA65):652		return mldsa.MLDSA65(), true653	case oid.Equal(oidPublicKeyMLDSA87):654		return mldsa.MLDSA87(), true655	}656	return mldsa.Parameters{}, false657}658659func oidFromMLDSAParameters(params mldsa.Parameters) (asn1.ObjectIdentifier, bool) {660	switch {661	case params == mldsa.MLDSA44():662		return oidPublicKeyMLDSA44, true663	case params == mldsa.MLDSA65():664		return oidPublicKeyMLDSA65, true665	case params == mldsa.MLDSA87():666		return oidPublicKeyMLDSA87, true667	}668	return nil, false669}670671// KeyUsage represents the set of actions that are valid for a given key. It's672// a bitmap of the KeyUsage* constants.673type KeyUsage int674675//go:generate stringer -linecomment -type=KeyUsage,ExtKeyUsage -output=x509_string.go676677const (678	KeyUsageDigitalSignature  KeyUsage = 1 << iota // digitalSignature679	KeyUsageContentCommitment                      // contentCommitment680	KeyUsageKeyEncipherment                        // keyEncipherment681	KeyUsageDataEncipherment                       // dataEncipherment682	KeyUsageKeyAgreement                           // keyAgreement683	KeyUsageCertSign                               // keyCertSign684	KeyUsageCRLSign                                // cRLSign685	KeyUsageEncipherOnly                           // encipherOnly686	KeyUsageDecipherOnly                           // decipherOnly687)688689// RFC 5280, 4.2.1.12  Extended Key Usage690//691//	anyExtendedKeyUsage OBJECT IDENTIFIER ::= { id-ce-extKeyUsage 0 }692//693//	id-kp OBJECT IDENTIFIER ::= { id-pkix 3 }694//695//	id-kp-serverAuth             OBJECT IDENTIFIER ::= { id-kp 1 }696//	id-kp-clientAuth             OBJECT IDENTIFIER ::= { id-kp 2 }697//	id-kp-codeSigning            OBJECT IDENTIFIER ::= { id-kp 3 }698//	id-kp-emailProtection        OBJECT IDENTIFIER ::= { id-kp 4 }699//	id-kp-timeStamping           OBJECT IDENTIFIER ::= { id-kp 8 }700//	id-kp-OCSPSigning            OBJECT IDENTIFIER ::= { id-kp 9 }701//702// https://www.iana.org/assignments/smi-numbers/smi-numbers.xhtml#smi-numbers-1.3.6.1.5.5.7.3703var (704	oidExtKeyUsageAny                            = asn1.ObjectIdentifier{2, 5, 29, 37, 0}705	oidExtKeyUsageServerAuth                     = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 1}706	oidExtKeyUsageClientAuth                     = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 2}707	oidExtKeyUsageCodeSigning                    = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 3}708	oidExtKeyUsageEmailProtection                = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 4}709	oidExtKeyUsageIPSECEndSystem                 = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 5}710	oidExtKeyUsageIPSECTunnel                    = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 6}711	oidExtKeyUsageIPSECUser                      = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 7}712	oidExtKeyUsageTimeStamping                   = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 8}713	oidExtKeyUsageOCSPSigning                    = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 9}714	oidExtKeyUsageMicrosoftServerGatedCrypto     = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 10, 3, 3}715	oidExtKeyUsageNetscapeServerGatedCrypto      = asn1.ObjectIdentifier{2, 16, 840, 1, 113730, 4, 1}716	oidExtKeyUsageMicrosoftCommercialCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 2, 1, 22}717	oidExtKeyUsageMicrosoftKernelCodeSigning     = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 61, 1, 1}718)719720// ExtKeyUsage represents an extended set of actions that are valid for a given key.721// Each of the ExtKeyUsage* constants define a unique action.722type ExtKeyUsage int723724const (725	ExtKeyUsageAny                            ExtKeyUsage = iota // anyExtendedKeyUsage726	ExtKeyUsageServerAuth                                        // serverAuth727	ExtKeyUsageClientAuth                                        // clientAuth728	ExtKeyUsageCodeSigning                                       // codeSigning729	ExtKeyUsageEmailProtection                                   // emailProtection730	ExtKeyUsageIPSECEndSystem                                    // ipsecEndSystem731	ExtKeyUsageIPSECTunnel                                       // ipsecTunnel732	ExtKeyUsageIPSECUser                                         // ipsecUser733	ExtKeyUsageTimeStamping                                      // timeStamping734	ExtKeyUsageOCSPSigning                                       // OCSPSigning735	ExtKeyUsageMicrosoftServerGatedCrypto                        // msSGC736	ExtKeyUsageNetscapeServerGatedCrypto                         // nsSGC737	ExtKeyUsageMicrosoftCommercialCodeSigning                    // msCodeCom738	ExtKeyUsageMicrosoftKernelCodeSigning                        // msKernelCode739)740741// extKeyUsageOIDs contains the mapping between an ExtKeyUsage and its OID.742var extKeyUsageOIDs = []struct {743	extKeyUsage ExtKeyUsage744	oid         asn1.ObjectIdentifier745}{746	{ExtKeyUsageAny, oidExtKeyUsageAny},747	{ExtKeyUsageServerAuth, oidExtKeyUsageServerAuth},748	{ExtKeyUsageClientAuth, oidExtKeyUsageClientAuth},749	{ExtKeyUsageCodeSigning, oidExtKeyUsageCodeSigning},750	{ExtKeyUsageEmailProtection, oidExtKeyUsageEmailProtection},751	{ExtKeyUsageIPSECEndSystem, oidExtKeyUsageIPSECEndSystem},752	{ExtKeyUsageIPSECTunnel, oidExtKeyUsageIPSECTunnel},753	{ExtKeyUsageIPSECUser, oidExtKeyUsageIPSECUser},754	{ExtKeyUsageTimeStamping, oidExtKeyUsageTimeStamping},755	{ExtKeyUsageOCSPSigning, oidExtKeyUsageOCSPSigning},756	{ExtKeyUsageMicrosoftServerGatedCrypto, oidExtKeyUsageMicrosoftServerGatedCrypto},757	{ExtKeyUsageNetscapeServerGatedCrypto, oidExtKeyUsageNetscapeServerGatedCrypto},758	{ExtKeyUsageMicrosoftCommercialCodeSigning, oidExtKeyUsageMicrosoftCommercialCodeSigning},759	{ExtKeyUsageMicrosoftKernelCodeSigning, oidExtKeyUsageMicrosoftKernelCodeSigning},760}761762func extKeyUsageFromOID(oid asn1.ObjectIdentifier) (eku ExtKeyUsage, ok bool) {763	for _, pair := range extKeyUsageOIDs {764		if oid.Equal(pair.oid) {765			return pair.extKeyUsage, true766		}767	}768	return769}770771func oidFromExtKeyUsage(eku ExtKeyUsage) (oid asn1.ObjectIdentifier, ok bool) {772	for _, pair := range extKeyUsageOIDs {773		if eku == pair.extKeyUsage {774			return pair.oid, true775		}776	}777	return778}779780// OID returns the ASN.1 object identifier of the EKU.781func (eku ExtKeyUsage) OID() OID {782	asn1OID, ok := oidFromExtKeyUsage(eku)783	if !ok {784		panic("x509: internal error: known ExtKeyUsage has no OID")785	}786	oid, err := OIDFromASN1OID(asn1OID)787	if err != nil {788		panic("x509: internal error: known ExtKeyUsage has invalid OID")789	}790	return oid791}792793// A Certificate represents an X.509 certificate.794type Certificate struct {795	Raw                     []byte // Complete ASN.1 DER content (certificate, signature algorithm and signature).796	RawTBSCertificate       []byte // Certificate part of raw ASN.1 DER content.797	RawSubjectPublicKeyInfo []byte // DER encoded SubjectPublicKeyInfo.798	RawSubject              []byte // DER encoded Subject799	RawIssuer               []byte // DER encoded Issuer800	RawSignatureAlgorithm   []byte // DER encoded AlgorithmIdentifier801802	Signature          []byte803	SignatureAlgorithm SignatureAlgorithm804805	PublicKeyAlgorithm PublicKeyAlgorithm806	PublicKey          any807808	Version             int809	SerialNumber        *big.Int810	Issuer              pkix.Name811	Subject             pkix.Name812	NotBefore, NotAfter time.Time // Validity bounds.813	KeyUsage            KeyUsage814815	// Extensions contains raw X.509 extensions. When parsing certificates,816	// this can be used to extract non-critical extensions that are not817	// parsed by this package. When marshaling certificates, the Extensions818	// field is ignored, see ExtraExtensions.819	Extensions []pkix.Extension820821	// ExtraExtensions contains extensions to be copied, raw, into any822	// marshaled certificates. Values override any extensions that would823	// otherwise be produced based on the other fields. The ExtraExtensions824	// field is not populated when parsing certificates, see Extensions.825	ExtraExtensions []pkix.Extension826827	// UnhandledCriticalExtensions contains a list of extension IDs that828	// were not (fully) processed when parsing. Verify will fail if this829	// slice is non-empty, unless verification is delegated to an OS830	// library which understands all the critical extensions.831	//832	// Users can access these extensions using Extensions and can remove833	// elements from this slice if they believe that they have been834	// handled.835	UnhandledCriticalExtensions []asn1.ObjectIdentifier836837	ExtKeyUsage        []ExtKeyUsage           // Sequence of extended key usages.838	UnknownExtKeyUsage []asn1.ObjectIdentifier // Encountered extended key usages unknown to this package.839840	// BasicConstraintsValid indicates whether IsCA, MaxPathLen,841	// and MaxPathLenZero are valid.842	BasicConstraintsValid bool843	IsCA                  bool844845	// MaxPathLen and MaxPathLenZero indicate the presence and846	// value of the BasicConstraints' "pathLenConstraint".847	//848	// When parsing a certificate, a positive non-zero MaxPathLen849	// means that the field was specified, -1 means it was unset,850	// and MaxPathLenZero being true mean that the field was851	// explicitly set to zero. The case of MaxPathLen==0 with MaxPathLenZero==false852	// should be treated equivalent to -1 (unset).853	//854	// When generating a certificate, an unset pathLenConstraint855	// can be requested with either MaxPathLen == -1 or using the856	// zero value for both MaxPathLen and MaxPathLenZero.857	MaxPathLen int858	// MaxPathLenZero indicates that BasicConstraintsValid==true859	// and MaxPathLen==0 should be interpreted as an actual860	// maximum path length of zero. Otherwise, that combination is861	// interpreted as MaxPathLen not being set.862	MaxPathLenZero bool863864	SubjectKeyId   []byte865	AuthorityKeyId []byte866867	// RFC 5280, 4.2.2.1 (Authority Information Access)868	OCSPServer            []string869	IssuingCertificateURL []string870871	// Subject Alternate Name values. (Note that these values may not be valid872	// if invalid values were contained within a parsed certificate. For873	// example, an element of DNSNames may not be a valid DNS domain name.)874	DNSNames       []string875	EmailAddresses []string876	IPAddresses    []net.IP877	URIs           []*url.URL878879	// Name constraints880	PermittedDNSDomainsCritical bool // if true then the name constraints are marked critical.881	PermittedDNSDomains         []string882	ExcludedDNSDomains          []string883	PermittedIPRanges           []*net.IPNet884	ExcludedIPRanges            []*net.IPNet885	PermittedEmailAddresses     []string886	ExcludedEmailAddresses      []string887	PermittedURIDomains         []string888	ExcludedURIDomains          []string889890	// CRL Distribution Points891	CRLDistributionPoints []string892893	// PolicyIdentifiers contains asn1.ObjectIdentifiers, the components894	// of which are limited to int32. If a certificate contains a policy which895	// cannot be represented by asn1.ObjectIdentifier, it will not be included in896	// PolicyIdentifiers, but will be present in Policies, which contains all parsed897	// policy OIDs.898	// See CreateCertificate for context about how this field and the Policies field899	// interact.900	PolicyIdentifiers []asn1.ObjectIdentifier901902	// Policies contains all policy identifiers included in the certificate.903	// See CreateCertificate for context about how this field and the PolicyIdentifiers field904	// interact.905	// In Go 1.22, encoding/gob cannot handle and ignores this field.906	Policies []OID907908	// InhibitAnyPolicy and InhibitAnyPolicyZero indicate the presence and value909	// of the inhibitAnyPolicy extension.910	//911	// The value of InhibitAnyPolicy indicates the number of additional912	// certificates in the path after this certificate that may use the913	// anyPolicy policy OID to indicate a match with any other policy.914	//915	// When parsing a certificate, a positive non-zero InhibitAnyPolicy means916	// that the field was specified, -1 means it was unset, and917	// InhibitAnyPolicyZero being true mean that the field was explicitly set to918	// zero. The case of InhibitAnyPolicy==0 with InhibitAnyPolicyZero==false919	// should be treated equivalent to -1 (unset).920	InhibitAnyPolicy int921	// InhibitAnyPolicyZero indicates that InhibitAnyPolicy==0 should be922	// interpreted as an actual maximum path length of zero. Otherwise, that923	// combination is interpreted as InhibitAnyPolicy not being set.924	InhibitAnyPolicyZero bool925926	// InhibitPolicyMapping and InhibitPolicyMappingZero indicate the presence927	// and value of the inhibitPolicyMapping field of the policyConstraints928	// extension.929	//930	// The value of InhibitPolicyMapping indicates the number of additional931	// certificates in the path after this certificate that may use policy932	// mapping.933	//934	// When parsing a certificate, a positive non-zero InhibitPolicyMapping935	// means that the field was specified, -1 means it was unset, and936	// InhibitPolicyMappingZero being true mean that the field was explicitly937	// set to zero. The case of InhibitPolicyMapping==0 with938	// InhibitPolicyMappingZero==false should be treated equivalent to -1939	// (unset).940	InhibitPolicyMapping int941	// InhibitPolicyMappingZero indicates that InhibitPolicyMapping==0 should be942	// interpreted as an actual maximum path length of zero. Otherwise, that943	// combination is interpreted as InhibitAnyPolicy not being set.944	InhibitPolicyMappingZero bool945946	// RequireExplicitPolicy and RequireExplicitPolicyZero indicate the presence947	// and value of the requireExplicitPolicy field of the policyConstraints948	// extension.949	//950	// The value of RequireExplicitPolicy indicates the number of additional951	// certificates in the path after this certificate before an explicit policy952	// is required for the rest of the path. When an explicit policy is required,953	// each subsequent certificate in the path must contain a required policy OID,954	// or a policy OID which has been declared as equivalent through the policy955	// mapping extension.956	//957	// When parsing a certificate, a positive non-zero RequireExplicitPolicy958	// means that the field was specified, -1 means it was unset, and959	// RequireExplicitPolicyZero being true mean that the field was explicitly960	// set to zero. The case of RequireExplicitPolicy==0 with961	// RequireExplicitPolicyZero==false should be treated equivalent to -1962	// (unset).963	RequireExplicitPolicy int964	// RequireExplicitPolicyZero indicates that RequireExplicitPolicy==0 should be965	// interpreted as an actual maximum path length of zero. Otherwise, that966	// combination is interpreted as InhibitAnyPolicy not being set.967	RequireExplicitPolicyZero bool968969	// PolicyMappings contains a list of policy mappings included in the certificate.970	PolicyMappings []PolicyMapping971}972973// PolicyMapping represents a policy mapping entry in the policyMappings extension.974type PolicyMapping struct {975	// IssuerDomainPolicy contains a policy OID the issuing certificate considers976	// equivalent to SubjectDomainPolicy in the subject certificate.977	IssuerDomainPolicy OID978	// SubjectDomainPolicy contains a OID the issuing certificate considers979	// equivalent to IssuerDomainPolicy in the subject certificate.980	SubjectDomainPolicy OID981}982983// ErrUnsupportedAlgorithm results from attempting to perform an operation that984// involves algorithms that are not currently implemented.985var ErrUnsupportedAlgorithm = errors.New("x509: cannot verify signature: algorithm unimplemented")986987// An InsecureAlgorithmError indicates that the [SignatureAlgorithm] used to988// generate the signature is not secure, and the signature has been rejected.989type InsecureAlgorithmError SignatureAlgorithm990991func (e InsecureAlgorithmError) Error() string {992	return fmt.Sprintf("x509: cannot verify signature: insecure algorithm %v", SignatureAlgorithm(e))993}994995// ConstraintViolationError results when a requested usage is not permitted by996// a certificate. For example: checking a signature when the public key isn't a997// certificate signing key.998type ConstraintViolationError struct{}9991000func (ConstraintViolationError) Error() string {1001	return "x509: invalid signature: parent certificate cannot sign this kind of certificate"1002}10031004func (c *Certificate) Equal(other *Certificate) bool {1005	if c == nil || other == nil {1006		return c == other1007	}1008	return bytes.Equal(c.Raw, other.Raw)1009}10101011func (c *Certificate) hasSANExtension() bool {1012	return oidInExtensions(oidExtensionSubjectAltName, c.Extensions)1013}10141015// CheckSignatureFrom verifies that the signature on c is a valid signature from parent.1016//1017// This is a low-level API that performs very limited checks, and not a full1018// path verifier. Most users should use [Certificate.Verify] instead.1019func (c *Certificate) CheckSignatureFrom(parent *Certificate) error {1020	// RFC 5280, 4.2.1.9:1021	// "If the basic constraints extension is not present in a version 31022	// certificate, or the extension is present but the cA boolean is not1023	// asserted, then the certified public key MUST NOT be used to verify1024	// certificate signatures."1025	if parent.Version == 3 && !parent.BasicConstraintsValid ||1026		parent.BasicConstraintsValid && !parent.IsCA {1027		return ConstraintViolationError{}1028	}10291030	if parent.KeyUsage != 0 && parent.KeyUsage&KeyUsageCertSign == 0 {1031		return ConstraintViolationError{}1032	}10331034	if parent.PublicKeyAlgorithm == UnknownPublicKeyAlgorithm {1035		return ErrUnsupportedAlgorithm1036	}10371038	return checkSignature(c.SignatureAlgorithm, c.RawTBSCertificate, c.Signature, parent.PublicKey, false)1039}10401041// CheckSignature verifies that signature is a valid signature over signed from1042// c's public key.1043//1044// This is a low-level API that performs no validity checks on the certificate.1045//1046// [MD5WithRSA] signatures are rejected, while [SHA1WithRSA] and [ECDSAWithSHA1]1047// signatures are currently accepted.1048func (c *Certificate) CheckSignature(algo SignatureAlgorithm, signed, signature []byte) error {1049	return checkSignature(algo, signed, signature, c.PublicKey, true)1050}10511052func (c *Certificate) hasNameConstraints() bool {1053	return oidInExtensions(oidExtensionNameConstraints, c.Extensions)1054}10551056func (c *Certificate) getSANExtension() []byte {1057	for _, e := range c.Extensions {1058		if e.Id.Equal(oidExtensionSubjectAltName) {1059			return e.Value1060		}1061	}1062	return nil1063}10641065func signaturePublicKeyAlgoMismatchError(expectedPubKeyAlgo PublicKeyAlgorithm, pubKey any) error {1066	return fmt.Errorf("x509: signature algorithm specifies an %s public key, but have public key of type %T", expectedPubKeyAlgo.String(), pubKey)1067}10681069func signatureMLDSAParametersMismatchError(expectedSigAlgo SignatureAlgorithm, pubKey *mldsa.PublicKey) error {1070	return fmt.Errorf("x509: signature algorithm specifies an ML-DSA public key with %s parameters, but have a public key with %s parameters", expectedSigAlgo, pubKey.Parameters())1071}10721073// checkSignature verifies that signature is a valid signature over signed from1074// a crypto.PublicKey.1075func checkSignature(algo SignatureAlgorithm, signed, signature []byte, publicKey crypto.PublicKey, allowSHA1 bool) (err error) {1076	var hashType crypto.Hash1077	var pubKeyAlgo PublicKeyAlgorithm10781079	for _, details := range signatureAlgorithmDetails {1080		if details.algo == algo {1081			hashType = details.hash1082			pubKeyAlgo = details.pubKeyAlgo1083			break1084		}1085	}10861087	switch hashType {1088	case crypto.Hash(0):1089		if pubKeyAlgo != Ed25519 && pubKeyAlgo != MLDSA {1090			return ErrUnsupportedAlgorithm1091		}1092	case crypto.MD5:1093		return InsecureAlgorithmError(algo)1094	case crypto.SHA1:1095		// SHA-1 signatures are only allowed for CRLs and CSRs.1096		if !allowSHA1 {1097			return InsecureAlgorithmError(algo)1098		}1099		fallthrough1100	default:1101		if !hashType.Available() {1102			return ErrUnsupportedAlgorithm1103		}1104		h := hashType.New()1105		h.Write(signed)1106		signed = h.Sum(nil)1107	}11081109	switch pub := publicKey.(type) {1110	case *rsa.PublicKey:1111		if pubKeyAlgo != RSA {1112			return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)1113		}1114		if algo.isRSAPSS() {1115			return rsa.VerifyPSS(pub, hashType, signed, signature, &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash})1116		} else {1117			return rsa.VerifyPKCS1v15(pub, hashType, signed, signature)1118		}1119	case *ecdsa.PublicKey:1120		if pubKeyAlgo != ECDSA {1121			return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)1122		}1123		if !ecdsa.VerifyASN1(pub, signed, signature) {1124			return errors.New("x509: ECDSA verification failure")1125		}1126		return1127	case ed25519.PublicKey:1128		if pubKeyAlgo != Ed25519 {1129			return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)1130		}1131		if !ed25519.Verify(pub, signed, signature) {1132			return errors.New("x509: Ed25519 verification failure")1133		}1134		return1135	case *mldsa.PublicKey:1136		if pubKeyAlgo != MLDSA {1137			return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)1138		}1139		switch pub.Parameters() {1140		case mldsa.MLDSA44():1141			if algo != MLDSA44 {1142				return signatureMLDSAParametersMismatchError(algo, pub)1143			}1144		case mldsa.MLDSA65():1145			if algo != MLDSA65 {1146				return signatureMLDSAParametersMismatchError(algo, pub)1147			}1148		case mldsa.MLDSA87():1149			if algo != MLDSA87 {1150				return signatureMLDSAParametersMismatchError(algo, pub)1151			}1152		default:1153			return fmt.Errorf("x509: unknown ML-DSA parameters: %s", pub.Parameters())1154		}1155		if err := mldsa.Verify(pub, signed, signature, nil); err != nil {1156			return fmt.Errorf("x509: ML-DSA verification failure: %w", err)1157		}1158		return1159	}1160	return ErrUnsupportedAlgorithm1161}11621163// CheckCRLSignature checks that the signature in crl is from c.1164//1165// Deprecated: Use [RevocationList.CheckSignatureFrom] instead.1166func (c *Certificate) CheckCRLSignature(crl *pkix.CertificateList) error {1167	algo := getSignatureAlgorithmFromAI(crl.SignatureAlgorithm)1168	return c.CheckSignature(algo, crl.TBSCertList.Raw, crl.SignatureValue.RightAlign())1169}11701171type UnhandledCriticalExtension struct{}11721173func (h UnhandledCriticalExtension) Error() string {1174	return "x509: unhandled critical extension"1175}11761177type basicConstraints struct {1178	IsCA       bool `asn1:"optional"`1179	MaxPathLen int  `asn1:"optional,default:-1"`1180}11811182// RFC 5280 4.2.1.41183type policyInformation struct {1184	Policy asn1.ObjectIdentifier1185	// policyQualifiers omitted1186}11871188const (1189	nameTypeEmail = 11190	nameTypeDNS   = 21191	nameTypeURI   = 61192	nameTypeIP    = 71193)11941195// RFC 5280, 4.2.2.11196type authorityInfoAccess struct {1197	Method   asn1.ObjectIdentifier1198	Location asn1.RawValue1199}12001201// RFC 5280, 4.2.1.141202type distributionPoint struct {1203	DistributionPoint distributionPointName `asn1:"optional,tag:0"`1204	Reason            asn1.BitString        `asn1:"optional,tag:1"`1205	CRLIssuer         asn1.RawValue         `asn1:"optional,tag:2"`1206}12071208type distributionPointName struct {1209	FullName     []asn1.RawValue  `asn1:"optional,tag:0"`1210	RelativeName pkix.RDNSequence `asn1:"optional,tag:1"`1211}12121213func reverseBitsInAByte(in byte) byte {1214	b1 := in>>4 | in<<41215	b2 := b1>>2&0x33 | b1<<2&0xcc1216	b3 := b2>>1&0x55 | b2<<1&0xaa1217	return b31218}12191220// asn1BitLength returns the bit-length of bitString by considering the1221// most-significant bit in a byte to be the "first" bit. This convention1222// matches ASN.1, but differs from almost everything else.1223func asn1BitLength(bitString []byte) int {1224	bitLen := len(bitString) * 812251226	for i := range bitString {1227		b := bitString[len(bitString)-i-1]12281229		for bit := uint(0); bit < 8; bit++ {1230			if (b>>bit)&1 == 1 {1231				return bitLen1232			}1233			bitLen--1234		}1235	}12361237	return 01238}12391240var (1241	oidExtensionSubjectKeyId          = []int{2, 5, 29, 14}1242	oidExtensionKeyUsage              = []int{2, 5, 29, 15}1243	oidExtensionExtendedKeyUsage      = []int{2, 5, 29, 37}1244	oidExtensionAuthorityKeyId        = []int{2, 5, 29, 35}1245	oidExtensionBasicConstraints      = []int{2, 5, 29, 19}1246	oidExtensionSubjectAltName        = []int{2, 5, 29, 17}1247	oidExtensionCertificatePolicies   = []int{2, 5, 29, 32}1248	oidExtensionNameConstraints       = []int{2, 5, 29, 30}1249	oidExtensionCRLDistributionPoints = []int{2, 5, 29, 31}1250	oidExtensionAuthorityInfoAccess   = []int{1, 3, 6, 1, 5, 5, 7, 1, 1}1251	oidExtensionCRLNumber             = []int{2, 5, 29, 20}1252	oidExtensionReasonCode            = []int{2, 5, 29, 21}1253)12541255var (1256	oidAuthorityInfoAccessOcsp    = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 1}1257	oidAuthorityInfoAccessIssuers = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 2}1258)12591260// oidInExtensions reports whether an extension with the given oid exists in1261// extensions.1262func oidInExtensions(oid asn1.ObjectIdentifier, extensions []pkix.Extension) bool {1263	for _, e := range extensions {1264		if e.Id.Equal(oid) {1265			return true1266		}1267	}1268	return false1269}12701271// marshalSANs marshals a list of addresses into a the contents of an X.5091272// SubjectAlternativeName extension.1273func marshalSANs(dnsNames, emailAddresses []string, ipAddresses []net.IP, uris []*url.URL) (derBytes []byte, err error) {1274	var rawValues []asn1.RawValue1275	for _, name := range dnsNames {1276		if err := isIA5String(name); err != nil {1277			return nil, err1278		}1279		rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeDNS, Class: 2, Bytes: []byte(name)})1280	}1281	for _, email := range emailAddresses {1282		if err := isIA5String(email); err != nil {1283			return nil, err1284		}1285		rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeEmail, Class: 2, Bytes: []byte(email)})1286	}1287	for _, rawIP := range ipAddresses {1288		// If possible, we always want to encode IPv4 addresses in 4 bytes.1289		ip := rawIP.To4()1290		if ip == nil {1291			ip = rawIP1292		}1293		rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeIP, Class: 2, Bytes: ip})1294	}1295	for _, uri := range uris {1296		uriStr := uri.String()1297		if err := isIA5String(uriStr); err != nil {1298			return nil, err1299		}1300		rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeURI, Class: 2, Bytes: []byte(uriStr)})1301	}1302	return asn1.Marshal(rawValues)1303}13041305func isIA5String(s string) error {1306	for _, r := range s {1307		// Per RFC5280 "IA5String is limited to the set of ASCII characters"1308		if r > unicode.MaxASCII {1309			return fmt.Errorf("x509: %q cannot be encoded as an IA5String", s)1310		}1311	}13121313	return nil1314}13151316var x509usepolicies = godebug.New("x509usepolicies")13171318func buildCertExtensions(template *Certificate, subjectIsEmpty bool, authorityKeyId []byte, subjectKeyId []byte) (ret []pkix.Extension, err error) {1319	ret = make([]pkix.Extension, 10 /* maximum number of elements. */)1320	n := 013211322	if template.KeyUsage != 0 &&1323		!oidInExtensions(oidExtensionKeyUsage, template.ExtraExtensions) {1324		ret[n], err = marshalKeyUsage(template.KeyUsage)1325		if err != nil {1326			return nil, err1327		}1328		n++1329	}13301331	if (len(template.ExtKeyUsage) > 0 || len(template.UnknownExtKeyUsage) > 0) &&1332		!oidInExtensions(oidExtensionExtendedKeyUsage, template.ExtraExtensions) {1333		ret[n], err = marshalExtKeyUsage(template.ExtKeyUsage, template.UnknownExtKeyUsage)1334		if err != nil {1335			return nil, err1336		}1337		n++1338	}13391340	if template.BasicConstraintsValid && !oidInExtensions(oidExtensionBasicConstraints, template.ExtraExtensions) {1341		ret[n], err = marshalBasicConstraints(template.IsCA, template.MaxPathLen, template.MaxPathLenZero)1342		if err != nil {1343			return nil, err1344		}1345		n++1346	}13471348	if len(subjectKeyId) > 0 && !oidInExtensions(oidExtensionSubjectKeyId, template.ExtraExtensions) {1349		ret[n].Id = oidExtensionSubjectKeyId1350		ret[n].Value, err = asn1.Marshal(subjectKeyId)1351		if err != nil {1352			return1353		}1354		n++1355	}13561357	if len(authorityKeyId) > 0 && !oidInExtensions(oidExtensionAuthorityKeyId, template.ExtraExtensions) {1358		ret[n].Id = oidExtensionAuthorityKeyId1359		ret[n].Value, err = asn1.Marshal(authKeyId{authorityKeyId})1360		if err != nil {1361			return1362		}1363		n++1364	}13651366	if (len(template.OCSPServer) > 0 || len(template.IssuingCertificateURL) > 0) &&1367		!oidInExtensions(oidExtensionAuthorityInfoAccess, template.ExtraExtensions) {1368		ret[n].Id = oidExtensionAuthorityInfoAccess1369		var aiaValues []authorityInfoAccess1370		for _, name := range template.OCSPServer {1371			aiaValues = append(aiaValues, authorityInfoAccess{1372				Method:   oidAuthorityInfoAccessOcsp,1373				Location: asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)},1374			})1375		}1376		for _, name := range template.IssuingCertificateURL {1377			aiaValues = append(aiaValues, authorityInfoAccess{1378				Method:   oidAuthorityInfoAccessIssuers,1379				Location: asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)},1380			})1381		}1382		ret[n].Value, err = asn1.Marshal(aiaValues)1383		if err != nil {1384			return1385		}1386		n++1387	}13881389	if (len(template.DNSNames) > 0 || len(template.EmailAddresses) > 0 || len(template.IPAddresses) > 0 || len(template.URIs) > 0) &&1390		!oidInExtensions(oidExtensionSubjectAltName, template.ExtraExtensions) {1391		ret[n].Id = oidExtensionSubjectAltName1392		// From RFC 5280, Section 4.2.1.6:1393		// “If the subject field contains an empty sequence ... then1394		// subjectAltName extension ... is marked as critical”1395		ret[n].Critical = subjectIsEmpty1396		ret[n].Value, err = marshalSANs(template.DNSNames, template.EmailAddresses, template.IPAddresses, template.URIs)1397		if err != nil {1398			return1399		}1400		n++1401	}14021403	usePolicies := x509usepolicies.Value() != "0"1404	if ((!usePolicies && len(template.PolicyIdentifiers) > 0) || (usePolicies && len(template.Policies) > 0)) &&1405		!oidInExtensions(oidExtensionCertificatePolicies, template.ExtraExtensions) {1406		ret[n], err = marshalCertificatePolicies(template.Policies, template.PolicyIdentifiers)1407		if err != nil {1408			return nil, err1409		}1410		n++1411	}14121413	if (len(template.PermittedDNSDomains) > 0 || len(template.ExcludedDNSDomains) > 0 ||1414		len(template.PermittedIPRanges) > 0 || len(template.ExcludedIPRanges) > 0 ||1415		len(template.PermittedEmailAddresses) > 0 || len(template.ExcludedEmailAddresses) > 0 ||1416		len(template.PermittedURIDomains) > 0 || len(template.ExcludedURIDomains) > 0) &&1417		!oidInExtensions(oidExtensionNameConstraints, template.ExtraExtensions) {1418		ret[n].Id = oidExtensionNameConstraints1419		ret[n].Critical = template.PermittedDNSDomainsCritical14201421		ipAndMask := func(ipNet *net.IPNet) ([]byte, error) {1422			maskedIP := ipNet.IP.Mask(ipNet.Mask)1423			// This is extremely unlikely to actually happen, but lets save people from doing something they1424			// probably shouldn't.1425			if len(maskedIP) == net.IPv6len && maskedIP.To4() != nil {1426				return nil, errors.New("x509: IP constraint contained IPv4-mapped IPv6 address with a IPv6 mask")1427			}1428			ipAndMask := make([]byte, 0, len(maskedIP)+len(ipNet.Mask))1429			ipAndMask = append(ipAndMask, maskedIP...)1430			ipAndMask = append(ipAndMask, ipNet.Mask...)1431			return ipAndMask, nil1432		}14331434		serialiseConstraints := func(dns []string, ips []*net.IPNet, emails []string, uriDomains []string) (der []byte, err error) {1435			var b cryptobyte.Builder14361437			for _, name := range dns {1438				if err = isIA5String(name); err != nil {1439					return nil, err1440				}14411442				b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {1443					b.AddASN1(cryptobyte_asn1.Tag(2).ContextSpecific(), func(b *cryptobyte.Builder) {1444						b.AddBytes([]byte(name))1445					})1446				})1447			}14481449			for _, ipNet := range ips {1450				encodedIPNet, err := ipAndMask(ipNet)1451				if err != nil {1452					return nil, err1453				}1454				b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {1455					b.AddASN1(cryptobyte_asn1.Tag(7).ContextSpecific(), func(b *cryptobyte.Builder) {1456						b.AddBytes(encodedIPNet)1457					})1458				})1459			}14601461			for _, email := range emails {1462				if err = isIA5String(email); err != nil {1463					return nil, err1464				}14651466				b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {1467					b.AddASN1(cryptobyte_asn1.Tag(1).ContextSpecific(), func(b *cryptobyte.Builder) {1468						b.AddBytes([]byte(email))1469					})1470				})1471			}14721473			for _, uriDomain := range uriDomains {1474				if err = isIA5String(uriDomain); err != nil {1475					return nil, err1476				}14771478				b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {1479					b.AddASN1(cryptobyte_asn1.Tag(6).ContextSpecific(), func(b *cryptobyte.Builder) {1480						b.AddBytes([]byte(uriDomain))1481					})1482				})1483			}14841485			return b.Bytes()1486		}14871488		permitted, err := serialiseConstraints(template.PermittedDNSDomains, template.PermittedIPRanges, template.PermittedEmailAddresses, template.PermittedURIDomains)1489		if err != nil {1490			return nil, err1491		}14921493		excluded, err := serialiseConstraints(template.ExcludedDNSDomains, template.ExcludedIPRanges, template.ExcludedEmailAddresses, template.ExcludedURIDomains)1494		if err != nil {1495			return nil, err1496		}14971498		var b cryptobyte.Builder1499		b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {1500			if len(permitted) > 0 {1501				b.AddASN1(cryptobyte_asn1.Tag(0).ContextSpecific().Constructed(), func(b *cryptobyte.Builder) {1502					b.AddBytes(permitted)1503				})1504			}15051506			if len(excluded) > 0 {1507				b.AddASN1(cryptobyte_asn1.Tag(1).ContextSpecific().Constructed(), func(b *cryptobyte.Builder) {1508					b.AddBytes(excluded)1509				})1510			}1511		})15121513		ret[n].Value, err = b.Bytes()1514		if err != nil {1515			return nil, err1516		}1517		n++1518	}15191520	if len(template.CRLDistributionPoints) > 0 &&1521		!oidInExtensions(oidExtensionCRLDistributionPoints, template.ExtraExtensions) {1522		ret[n].Id = oidExtensionCRLDistributionPoints15231524		var crlDp []distributionPoint1525		for _, name := range template.CRLDistributionPoints {1526			dp := distributionPoint{1527				DistributionPoint: distributionPointName{1528					FullName: []asn1.RawValue{1529						{Tag: 6, Class: 2, Bytes: []byte(name)},1530					},1531				},1532			}1533			crlDp = append(crlDp, dp)1534		}15351536		ret[n].Value, err = asn1.Marshal(crlDp)1537		if err != nil {1538			return1539		}1540		n++1541	}15421543	// Adding another extension here? Remember to update the maximum number1544	// of elements in the make() at the top of the function and the list of1545	// template fields used in CreateCertificate documentation.15461547	return append(ret[:n], template.ExtraExtensions...), nil1548}15491550func marshalKeyUsage(ku KeyUsage) (pkix.Extension, error) {1551	ext := pkix.Extension{Id: oidExtensionKeyUsage, Critical: true}15521553	var a [2]byte1554	a[0] = reverseBitsInAByte(byte(ku))1555	a[1] = reverseBitsInAByte(byte(ku >> 8))15561557	l := 11558	if a[1] != 0 {1559		l = 21560	}15611562	bitString := a[:l]1563	var err error1564	ext.Value, err = asn1.Marshal(asn1.BitString{Bytes: bitString, BitLength: asn1BitLength(bitString)})1565	return ext, err1566}15671568func marshalExtKeyUsage(extUsages []ExtKeyUsage, unknownUsages []asn1.ObjectIdentifier) (pkix.Extension, error) {1569	ext := pkix.Extension{Id: oidExtensionExtendedKeyUsage}15701571	oids := make([]asn1.ObjectIdentifier, len(extUsages)+len(unknownUsages))1572	for i, u := range extUsages {1573		if oid, ok := oidFromExtKeyUsage(u); ok {1574			oids[i] = oid1575		} else {1576			return ext, errors.New("x509: unknown extended key usage")1577		}1578	}15791580	copy(oids[len(extUsages):], unknownUsages)15811582	var err error1583	ext.Value, err = asn1.Marshal(oids)1584	return ext, err1585}15861587func marshalBasicConstraints(isCA bool, maxPathLen int, maxPathLenZero bool) (pkix.Extension, error) {1588	ext := pkix.Extension{Id: oidExtensionBasicConstraints, Critical: true}1589	// Leaving MaxPathLen as zero indicates that no maximum path1590	// length is desired, unless MaxPathLenZero is set. A value of1591	// -1 causes encoding/asn1 to omit the value as desired.1592	if maxPathLen == 0 && !maxPathLenZero {1593		maxPathLen = -11594	}1595	var err error1596	ext.Value, err = asn1.Marshal(basicConstraints{isCA, maxPathLen})1597	return ext, err1598}15991600func marshalCertificatePolicies(policies []OID, policyIdentifiers []asn1.ObjectIdentifier) (pkix.Extension, error) {1601	ext := pkix.Extension{Id: oidExtensionCertificatePolicies}16021603	b := cryptobyte.NewBuilder(make([]byte, 0, 128))1604	b.AddASN1(cryptobyte_asn1.SEQUENCE, func(child *cryptobyte.Builder) {1605		if x509usepolicies.Value() != "0" {1606			x509usepolicies.IncNonDefault()1607			for _, v := range policies {1608				child.AddASN1(cryptobyte_asn1.SEQUENCE, func(child *cryptobyte.Builder) {1609					child.AddASN1(cryptobyte_asn1.OBJECT_IDENTIFIER, func(child *cryptobyte.Builder) {1610						if len(v.der) == 0 {1611							child.SetError(errors.New("invalid policy object identifier"))1612							return1613						}1614						child.AddBytes(v.der)1615					})1616				})1617			}1618		} else {1619			for _, v := range policyIdentifiers {1620				child.AddASN1(cryptobyte_asn1.SEQUENCE, func(child *cryptobyte.Builder) {1621					child.AddASN1ObjectIdentifier(v)1622				})1623			}1624		}1625	})16261627	var err error1628	ext.Value, err = b.Bytes()1629	return ext, err1630}16311632func buildCSRExtensions(template *CertificateRequest) ([]pkix.Extension, error) {1633	var ret []pkix.Extension16341635	if (len(template.DNSNames) > 0 || len(template.EmailAddresses) > 0 || len(template.IPAddresses) > 0 || len(template.URIs) > 0) &&1636		!oidInExtensions(oidExtensionSubjectAltName, template.ExtraExtensions) {1637		sanBytes, err := marshalSANs(template.DNSNames, template.EmailAddresses, template.IPAddresses, template.URIs)1638		if err != nil {1639			return nil, err1640		}16411642		ret = append(ret, pkix.Extension{1643			Id:    oidExtensionSubjectAltName,1644			Value: sanBytes,1645		})1646	}16471648	return append(ret, template.ExtraExtensions...), nil1649}16501651func subjectBytes(cert *Certificate) ([]byte, error) {1652	if len(cert.RawSubject) > 0 {1653		return cert.RawSubject, nil1654	}16551656	return asn1.Marshal(cert.Subject.ToRDNSequence())1657}16581659// signingParamsForKey returns the signature algorithm and its Algorithm1660// Identifier to use for signing, based on the key type. If sigAlgo is not zero1661// then it overrides the default.1662func signingParamsForKey(key crypto.Signer, sigAlgo SignatureAlgorithm) (SignatureAlgorithm, pkix.AlgorithmIdentifier, error) {1663	var ai pkix.AlgorithmIdentifier1664	var pubType PublicKeyAlgorithm1665	var defaultAlgo SignatureAlgorithm16661667	switch pub := key.Public().(type) {1668	case *rsa.PublicKey:1669		pubType = RSA1670		defaultAlgo = SHA256WithRSA16711672	case *ecdsa.PublicKey:1673		pubType = ECDSA1674		switch pub.Curve {1675		case elliptic.P224(), elliptic.P256():1676			defaultAlgo = ECDSAWithSHA2561677		case elliptic.P384():1678			defaultAlgo = ECDSAWithSHA3841679		case elliptic.P521():1680			defaultAlgo = ECDSAWithSHA5121681		default:1682			return 0, ai, errors.New("x509: unsupported elliptic curve")1683		}16841685	case ed25519.PublicKey:1686		pubType = Ed255191687		defaultAlgo = PureEd2551916881689	case *mldsa.PublicKey:1690		pubType = MLDSA1691		switch pub.Parameters() {1692		case mldsa.MLDSA44():1693			defaultAlgo = MLDSA441694		case mldsa.MLDSA65():1695			defaultAlgo = MLDSA651696		case mldsa.MLDSA87():1697			defaultAlgo = MLDSA871698		default:1699			return 0, ai, fmt.Errorf("x509: unsupported ML-DSA parameters: %s", pub.Parameters())1700		}17011702	default:1703		return 0, ai, errors.New("x509: only RSA, ECDSA, ML-DSA and Ed25519 keys supported")1704	}17051706	if sigAlgo == 0 {1707		sigAlgo = defaultAlgo1708	}17091710	for _, details := range signatureAlgorithmDetails {1711		if details.algo == sigAlgo {1712			if details.pubKeyAlgo != pubType {1713				return 0, ai, errors.New("x509: requested SignatureAlgorithm does not match private key type")1714			}1715			if pubType == MLDSA && sigAlgo != defaultAlgo {1716				return 0, ai, errors.New("x509: requested SignatureAlgorithm does not match ML-DSA parameters")1717			}1718			if details.hash == crypto.MD5 {1719				return 0, ai, errors.New("x509: signing with MD5 is not supported")1720			}17211722			return sigAlgo, pkix.AlgorithmIdentifier{1723				Algorithm:  details.oid,1724				Parameters: details.params,1725			}, nil1726		}1727	}17281729	return 0, ai, errors.New("x509: unknown SignatureAlgorithm")1730}17311732func signTBS(tbs []byte, key crypto.Signer, sigAlg SignatureAlgorithm, rand io.Reader) ([]byte, error) {1733	hashFunc := sigAlg.hashFunc()17341735	var signerOpts crypto.SignerOpts = hashFunc1736	if sigAlg.isRSAPSS() {1737		signerOpts = &rsa.PSSOptions{1738			SaltLength: rsa.PSSSaltLengthEqualsHash,1739			Hash:       hashFunc,1740		}1741	}17421743	signature, err := crypto.SignMessage(key, rand, tbs, signerOpts)1744	if err != nil {1745		return nil, err1746	}17471748	// Check the signature to ensure the crypto.Signer behaved correctly.1749	if err := checkSignature(sigAlg, tbs, signature, key.Public(), true); err != nil {1750		return nil, fmt.Errorf("x509: signature returned by signer is invalid: %w", err)1751	}17521753	return signature, nil1754}17551756// emptyASN1Subject is the ASN.1 DER encoding of an empty Subject, which is1757// just an empty SEQUENCE.1758var emptyASN1Subject = []byte{0x30, 0}17591760// CreateCertificate creates a new X.509 v3 certificate based on a template.1761// The following members of template are currently used:1762//1763//   - AuthorityKeyId1764//   - BasicConstraintsValid1765//   - CRLDistributionPoints1766//   - DNSNames1767//   - EmailAddresses1768//   - ExcludedDNSDomains1769//   - ExcludedEmailAddresses1770//   - ExcludedIPRanges1771//   - ExcludedURIDomains1772//   - ExtKeyUsage1773//   - ExtraExtensions1774//   - IPAddresses1775//   - IsCA1776//   - IssuingCertificateURL1777//   - KeyUsage1778//   - MaxPathLen1779//   - MaxPathLenZero1780//   - NotAfter1781//   - NotBefore1782//   - OCSPServer1783//   - PermittedDNSDomains1784//   - PermittedDNSDomainsCritical1785//   - PermittedEmailAddresses1786//   - PermittedIPRanges1787//   - PermittedURIDomains1788//   - PolicyIdentifiers (see note below)1789//   - Policies (see note below)1790//   - SerialNumber1791//   - SignatureAlgorithm1792//   - Subject1793//   - SubjectKeyId1794//   - URIs1795//   - UnknownExtKeyUsage1796//1797// The certificate is signed by parent. If parent is equal to template then the1798// certificate is self-signed. The parameter pub is the public key of the1799// certificate to be generated and priv is the private key of the signer.1800//1801// The returned slice is the certificate in DER encoding.1802//1803// The currently supported key types are *rsa.PublicKey, *ecdsa.PublicKey,1804// ed25519.PublicKey, and *mldsa.PublicKey. pub must be a supported key type,1805// and priv must be a crypto.Signer or crypto.MessageSigner with a supported1806// public key.1807//1808// The AuthorityKeyId will be taken from the SubjectKeyId of parent, if any,1809// unless the resulting certificate is self-signed. Otherwise the value from1810// template will be used.1811//1812// If SubjectKeyId from template is empty and the template is a CA, SubjectKeyId1813// will be generated from the hash of the public key.1814//1815// If template.SerialNumber is nil, a serial number will be generated which1816// conforms to RFC 5280, Section 4.1.2.2 using entropy from rand.1817//1818// The PolicyIdentifier and Policies fields can both be used to marshal certificate1819// policy OIDs. By default, only the Policies is marshaled, but if the1820// GODEBUG setting "x509usepolicies" has the value "0", the PolicyIdentifiers field will1821// be marshaled instead of the Policies field. This changed in Go 1.24. The Policies field can1822// be used to marshal policy OIDs which have components that are larger than 311823// bits.1824//1825// IP addresses in IPAddresses which are in their IPv4-mapped IPv6 form will always be encoded1826// in their IPv4 form.1827func CreateCertificate(rand io.Reader, template, parent *Certificate, pub, priv any) ([]byte, error) {1828	key, ok := priv.(crypto.Signer)1829	if !ok {1830		return nil, errors.New("x509: certificate private key does not implement crypto.Signer")1831	}18321833	serialNumber := template.SerialNumber1834	if serialNumber == nil {1835		// Generate a serial number following RFC 5280, Section 4.1.2.2 if one1836		// is not provided. The serial number must be positive and at most 201837		// octets *when encoded*.1838		serialBytes := make([]byte, 20)1839		if _, err := io.ReadFull(rand, serialBytes); err != nil {1840			return nil, err1841		}1842		// If the top bit is set, the serial will be padded with a leading zero1843		// byte during encoding, so that it's not interpreted as a negative1844		// integer. This padding would make the serial 21 octets so we clear the1845		// top bit to ensure the correct length in all cases.1846		serialBytes[0] &= 0b0111_11111847		serialNumber = new(big.Int).SetBytes(serialBytes)1848	}18491850	// RFC 5280 Section 4.1.2.2: serial number must be positive1851	//1852	// We _should_ also restrict serials to <= 20 octets, but it turns out a lot of people1853	// get this wrong, in part because the encoding can itself alter the length of the1854	// serial. For now we accept these non-conformant serials.1855	if serialNumber.Sign() == -1 {1856		return nil, errors.New("x509: serial number must be positive")1857	}18581859	if template.BasicConstraintsValid && template.MaxPathLen < -1 {1860		return nil, errors.New("x509: invalid MaxPathLen, must be greater or equal to -1")1861	}18621863	if template.BasicConstraintsValid && !template.IsCA && template.MaxPathLen != -1 && (template.MaxPathLen != 0 || template.MaxPathLenZero) {1864		return nil, errors.New("x509: only CAs are allowed to specify MaxPathLen")1865	}18661867	signatureAlgorithm, algorithmIdentifier, err := signingParamsForKey(key, template.SignatureAlgorithm)1868	if err != nil {1869		return nil, err1870	}18711872	publicKeyBytes, publicKeyAlgorithm, err := marshalPublicKey(pub)1873	if err != nil {1874		return nil, err1875	}1876	if getPublicKeyAlgorithmFromOID(publicKeyAlgorithm.Algorithm) == UnknownPublicKeyAlgorithm {1877		return nil, fmt.Errorf("x509: unsupported public key type: %T", pub)1878	}18791880	asn1Issuer, err := subjectBytes(parent)1881	if err != nil {1882		return nil, err1883	}18841885	asn1Subject, err := subjectBytes(template)1886	if err != nil {1887		return nil, err1888	}18891890	authorityKeyId := template.AuthorityKeyId1891	if !bytes.Equal(asn1Issuer, asn1Subject) && len(parent.SubjectKeyId) > 0 {1892		authorityKeyId = parent.SubjectKeyId1893	}18941895	subjectKeyId := template.SubjectKeyId1896	if len(subjectKeyId) == 0 && template.IsCA {1897		if x509sha256skid.Value() == "0" {1898			x509sha256skid.IncNonDefault()1899			// SubjectKeyId generated using method 1 in RFC 5280, Section 4.2.1.2:1900			//   (1) The keyIdentifier is composed of the 160-bit SHA-1 hash of the1901			//   value of the BIT STRING subjectPublicKey (excluding the tag,1902			//   length, and number of unused bits).1903			h := sha1.Sum(publicKeyBytes)1904			subjectKeyId = h[:]1905		} else {1906			// SubjectKeyId generated using method 1 in RFC 7093, Section 2:1907			//    1) The keyIdentifier is composed of the leftmost 160-bits of the1908			//    SHA-256 hash of the value of the BIT STRING subjectPublicKey1909			//    (excluding the tag, length, and number of unused bits).1910			h := sha256.Sum256(publicKeyBytes)1911			subjectKeyId = h[:20]1912		}1913	}19141915	// Check that the signer's public key matches the private key, if available.1916	type privateKey interface {1917		Equal(crypto.PublicKey) bool1918	}1919	if privPub, ok := key.Public().(privateKey); !ok {1920		return nil, errors.New("x509: internal error: supported public key does not implement Equal")1921	} else if parent.PublicKey != nil && !privPub.Equal(parent.PublicKey) {1922		return nil, errors.New("x509: provided PrivateKey doesn't match parent's PublicKey")1923	}19241925	extensions, err := buildCertExtensions(template, bytes.Equal(asn1Subject, emptyASN1Subject), authorityKeyId, subjectKeyId)1926	if err != nil {1927		return nil, err1928	}19291930	encodedPublicKey := asn1.BitString{BitLength: len(publicKeyBytes) * 8, Bytes: publicKeyBytes}1931	c := tbsCertificate{1932		Version:            2,1933		SerialNumber:       serialNumber,1934		SignatureAlgorithm: algorithmIdentifier,1935		Issuer:             asn1.RawValue{FullBytes: asn1Issuer},1936		Validity:           validity{template.NotBefore.UTC(), template.NotAfter.UTC()},1937		Subject:            asn1.RawValue{FullBytes: asn1Subject},1938		PublicKey:          publicKeyInfo{nil, publicKeyAlgorithm, encodedPublicKey},1939		Extensions:         extensions,1940	}19411942	tbsCertContents, err := asn1.Marshal(c)1943	if err != nil {1944		return nil, err1945	}1946	c.Raw = tbsCertContents19471948	signature, err := signTBS(tbsCertContents, key, signatureAlgorithm, rand)1949	if err != nil {1950		return nil, err1951	}19521953	return asn1.Marshal(certificate{1954		TBSCertificate:     c,1955		SignatureAlgorithm: algorithmIdentifier,1956		SignatureValue:     asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},1957	})1958}19591960var x509sha256skid = godebug.New("x509sha256skid")19611962// pemCRLPrefix is the magic string that indicates that we have a PEM encoded1963// CRL.1964var pemCRLPrefix = []byte("-----BEGIN X509 CRL")19651966// pemType is the type of a PEM encoded CRL.1967var pemType = "X509 CRL"19681969// ParseCRL parses a CRL from the given bytes. It's often the case that PEM1970// encoded CRLs will appear where they should be DER encoded, so this function1971// will transparently handle PEM encoding as long as there isn't any leading1972// garbage.1973//1974// Deprecated: Use [ParseRevocationList] instead.1975func ParseCRL(crlBytes []byte) (*pkix.CertificateList, error) {1976	if bytes.HasPrefix(crlBytes, pemCRLPrefix) {1977		block, _ := pem.Decode(crlBytes)1978		if block != nil && block.Type == pemType {1979			crlBytes = block.Bytes1980		}1981	}1982	return ParseDERCRL(crlBytes)1983}19841985// ParseDERCRL parses a DER encoded CRL from the given bytes.1986//1987// Deprecated: Use [ParseRevocationList] instead.1988func ParseDERCRL(derBytes []byte) (*pkix.CertificateList, error) {1989	certList := new(pkix.CertificateList)1990	if rest, err := asn1.Unmarshal(derBytes, certList); err != nil {1991		return nil, err1992	} else if len(rest) != 0 {1993		return nil, errors.New("x509: trailing data after CRL")1994	}1995	return certList, nil1996}19971998// CreateCRL returns a DER encoded CRL, signed by this Certificate, that1999// contains the given list of revoked certificates.2000//