// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package x509 implements a subset of the X.509 standard.
//
// It allows parsing and generating certificates, certificate signing
// requests, certificate revocation lists, and encoded public and private keys.
// It provides a certificate verifier, complete with a chain builder.
//
// The package targets the X.509 technical profile defined by the IETF (RFC
// 2459/3280/5280), and as further restricted by the CA/Browser Forum Baseline
// Requirements. There is minimal support for features outside of these
// profiles, as the primary goal of the package is to provide compatibility
// with the publicly trusted TLS certificate ecosystem and its policies and
// constraints.
//
// On macOS and Windows, certificate verification is handled by system APIs, but
// the package aims to apply consistent validation rules across operating
// systems.
package x509
import (
"bytes"
"crypto"
"crypto/ecdh"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
cryptorand "crypto/rand"
"crypto/rsa"
"crypto/sha1"
"crypto/x509/pkix"
"encoding/asn1"
"encoding/pem"
"errors"
"fmt"
"internal/godebug"
"io"
"math/big"
"net"
"net/url"
"strconv"
"time"
"unicode"
// Explicitly import these for their crypto.RegisterHash init side-effects.
// Keep these as blank imports, even if they're imported above.
_ "crypto/sha1"
_ "crypto/sha256"
_ "crypto/sha512"
"golang.org/x/crypto/cryptobyte"
cryptobyte_asn1 "golang.org/x/crypto/cryptobyte/asn1"
)
// pkixPublicKey reflects a PKIX public key structure. See SubjectPublicKeyInfo
// in RFC 3280.
type pkixPublicKey struct {
Algo pkix.AlgorithmIdentifier
BitString asn1.BitString
}
// ParsePKIXPublicKey parses a public key in PKIX, ASN.1 DER form. The encoded
// public key is a SubjectPublicKeyInfo structure (see RFC 5280, Section 4.1).
//
// It returns a *[rsa.PublicKey], *[dsa.PublicKey], *[ecdsa.PublicKey],
// [ed25519.PublicKey] (not a pointer), or *[ecdh.PublicKey] (for X25519).
// More types might be supported in the future.
//
// This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".
func ParsePKIXPublicKey(derBytes []byte) (pub any, err error) {
var pki publicKeyInfo
if rest, err := asn1.Unmarshal(derBytes, &pki); err != nil {
if _, err := asn1.Unmarshal(derBytes, &pkcs1PublicKey{}); err == nil {
return nil, errors.New("x509: failed to parse public key (use ParsePKCS1PublicKey instead for this key format)")
}
return nil, err
} else if len(rest) != 0 {
return nil, errors.New("x509: trailing data after ASN.1 of public-key")
}
return parsePublicKey(&pki)
}
func marshalPublicKey(pub any) (publicKeyBytes []byte, publicKeyAlgorithm pkix.AlgorithmIdentifier, err error) {
switch pub := pub.(type) {
case *rsa.PublicKey:
publicKeyBytes, err = asn1.Marshal(pkcs1PublicKey{
N: pub.N,
E: pub.E,
})
if err != nil {
return nil, pkix.AlgorithmIdentifier{}, err
}
publicKeyAlgorithm.Algorithm = oidPublicKeyRSA
// This is a NULL parameters value which is required by
// RFC 3279, Section 2.3.1.
publicKeyAlgorithm.Parameters = asn1.NullRawValue
case *ecdsa.PublicKey:
oid, ok := oidFromNamedCurve(pub.Curve)
if !ok {
return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")
}
if !pub.Curve.IsOnCurve(pub.X, pub.Y) {
return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: invalid elliptic curve public key")
}
publicKeyBytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)
publicKeyAlgorithm.Algorithm = oidPublicKeyECDSA
var paramBytes []byte
paramBytes, err = asn1.Marshal(oid)
if err != nil {
return
}
publicKeyAlgorithm.Parameters.FullBytes = paramBytes
case ed25519.PublicKey:
publicKeyBytes = pub
publicKeyAlgorithm.Algorithm = oidPublicKeyEd25519
case *ecdh.PublicKey:
publicKeyBytes = pub.Bytes()
if pub.Curve() == ecdh.X25519() {
publicKeyAlgorithm.Algorithm = oidPublicKeyX25519
} else {
oid, ok := oidFromECDHCurve(pub.Curve())
if !ok {
return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")
}
publicKeyAlgorithm.Algorithm = oidPublicKeyECDSA
var paramBytes []byte
paramBytes, err = asn1.Marshal(oid)
if err != nil {
return
}
publicKeyAlgorithm.Parameters.FullBytes = paramBytes
}
default:
return nil, pkix.AlgorithmIdentifier{}, fmt.Errorf("x509: unsupported public key type: %T", pub)
}
return publicKeyBytes, publicKeyAlgorithm, nil
}
// MarshalPKIXPublicKey converts a public key to PKIX, ASN.1 DER form.
// The encoded public key is a SubjectPublicKeyInfo structure
// (see RFC 5280, Section 4.1).
//
// The following key types are currently supported: *[rsa.PublicKey],
// *[ecdsa.PublicKey], [ed25519.PublicKey] (not a pointer), and *[ecdh.PublicKey].
// Unsupported key types result in an error.
//
// This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".
func MarshalPKIXPublicKey(pub any) ([]byte, error) {
var publicKeyBytes []byte
var publicKeyAlgorithm pkix.AlgorithmIdentifier
var err error
if publicKeyBytes, publicKeyAlgorithm, err = marshalPublicKey(pub); err != nil {
return nil, err
}
pkix := pkixPublicKey{
Algo: publicKeyAlgorithm,
BitString: asn1.BitString{
Bytes: publicKeyBytes,
BitLength: 8 * len(publicKeyBytes),
},
}
ret, _ := asn1.Marshal(pkix)
return ret, nil
}
// These structures reflect the ASN.1 structure of X.509 certificates.:
type certificate struct {
TBSCertificate tbsCertificate
SignatureAlgorithm pkix.AlgorithmIdentifier
SignatureValue asn1.BitString
}
type tbsCertificate struct {
Raw asn1.RawContent
Version int `asn1:"optional,explicit,default:0,tag:0"`
SerialNumber *big.Int
SignatureAlgorithm pkix.AlgorithmIdentifier
Issuer asn1.RawValue
Validity validity
Subject asn1.RawValue
PublicKey publicKeyInfo
UniqueId asn1.BitString `asn1:"optional,tag:1"`
SubjectUniqueId asn1.BitString `asn1:"optional,tag:2"`
Extensions []pkix.Extension `asn1:"omitempty,optional,explicit,tag:3"`
}
type dsaAlgorithmParameters struct {
P, Q, G *big.Int
}
type validity struct {
NotBefore, NotAfter time.Time
}
type publicKeyInfo struct {
Raw asn1.RawContent
Algorithm pkix.AlgorithmIdentifier
PublicKey asn1.BitString
}
// RFC 5280, 4.2.1.1
type authKeyId struct {
Id []byte `asn1:"optional,tag:0"`
}
type SignatureAlgorithm int
const (
UnknownSignatureAlgorithm SignatureAlgorithm = iota
MD2WithRSA // Unsupported.
MD5WithRSA // Only supported for signing, not verification.
SHA1WithRSA // Only supported for signing, and verification of CRLs, CSRs, and OCSP responses.
SHA256WithRSA
SHA384WithRSA
SHA512WithRSA
DSAWithSHA1 // Unsupported.
DSAWithSHA256 // Unsupported.
ECDSAWithSHA1 // Only supported for signing, and verification of CRLs, CSRs, and OCSP responses.
ECDSAWithSHA256
ECDSAWithSHA384
ECDSAWithSHA512
SHA256WithRSAPSS
SHA384WithRSAPSS
SHA512WithRSAPSS
PureEd25519
)
func (algo SignatureAlgorithm) isRSAPSS() bool {
for _, details := range signatureAlgorithmDetails {
if details.algo == algo {
return details.isRSAPSS
}
}
return false
}
func (algo SignatureAlgorithm) hashFunc() crypto.Hash {
for _, details := range signatureAlgorithmDetails {
if details.algo == algo {
return details.hash
}
}
return crypto.Hash(0)
}
func (algo SignatureAlgorithm) String() string {
for _, details := range signatureAlgorithmDetails {
if details.algo == algo {
return details.name
}
}
return strconv.Itoa(int(algo))
}
type PublicKeyAlgorithm int
const (
UnknownPublicKeyAlgorithm PublicKeyAlgorithm = iota
RSA
DSA // Only supported for parsing.
ECDSA
Ed25519
)
var publicKeyAlgoName = [...]string{
RSA: "RSA",
DSA: "DSA",
ECDSA: "ECDSA",
Ed25519: "Ed25519",
}
func (algo PublicKeyAlgorithm) String() string {
if 0 < algo && int(algo) < len(publicKeyAlgoName) {
return publicKeyAlgoName[algo]
}
return strconv.Itoa(int(algo))
}
// OIDs for signature algorithms
//
// pkcs-1 OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 1 }
//
// RFC 3279 2.2.1 RSA Signature Algorithms
//
// md5WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 4 }
//
// sha-1WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 5 }
//
// dsaWithSha1 OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) x9-57(10040) x9cm(4) 3 }
//
// RFC 3279 2.2.3 ECDSA Signature Algorithm
//
// ecdsa-with-SHA1 OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) ansi-x962(10045)
// signatures(4) ecdsa-with-SHA1(1)}
//
// RFC 4055 5 PKCS #1 Version 1.5
//
// sha256WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 11 }
//
// sha384WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 12 }
//
// sha512WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 13 }
//
// RFC 5758 3.1 DSA Signature Algorithms
//
// dsaWithSha256 OBJECT IDENTIFIER ::= {
// joint-iso-ccitt(2) country(16) us(840) organization(1) gov(101)
// csor(3) algorithms(4) id-dsa-with-sha2(3) 2}
//
// RFC 5758 3.2 ECDSA Signature Algorithm
//
// ecdsa-with-SHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
// us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 2 }
//
// ecdsa-with-SHA384 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
// us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 3 }
//
// ecdsa-with-SHA512 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
// us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 4 }
//
// RFC 8410 3 Curve25519 and Curve448 Algorithm Identifiers
//
// id-Ed25519 OBJECT IDENTIFIER ::= { 1 3 101 112 }
var (
oidSignatureMD5WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 4}
oidSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}
oidSignatureSHA256WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 11}
oidSignatureSHA384WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 12}
oidSignatureSHA512WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 13}
oidSignatureRSAPSS = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 10}
oidSignatureDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 3}
oidSignatureDSAWithSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 3, 2}
oidSignatureECDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 1}
oidSignatureECDSAWithSHA256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 2}
oidSignatureECDSAWithSHA384 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 3}
oidSignatureECDSAWithSHA512 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 4}
oidSignatureEd25519 = asn1.ObjectIdentifier{1, 3, 101, 112}
oidSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 1}
oidSHA384 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 2}
oidSHA512 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 3}
oidMGF1 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 8}
// oidISOSignatureSHA1WithRSA means the same as oidSignatureSHA1WithRSA
// but it's specified by ISO. Microsoft's makecert.exe has been known
// to produce certificates with this OID.
oidISOSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 3, 14, 3, 2, 29}
)
var signatureAlgorithmDetails = []struct {
algo SignatureAlgorithm
name string
oid asn1.ObjectIdentifier
params asn1.RawValue
pubKeyAlgo PublicKeyAlgorithm
hash crypto.Hash
isRSAPSS bool
}{
{MD5WithRSA, "MD5-RSA", oidSignatureMD5WithRSA, asn1.NullRawValue, RSA, crypto.MD5, false},
{SHA1WithRSA, "SHA1-RSA", oidSignatureSHA1WithRSA, asn1.NullRawValue, RSA, crypto.SHA1, false},
{SHA1WithRSA, "SHA1-RSA", oidISOSignatureSHA1WithRSA, asn1.NullRawValue, RSA, crypto.SHA1, false},
{SHA256WithRSA, "SHA256-RSA", oidSignatureSHA256WithRSA, asn1.NullRawValue, RSA, crypto.SHA256, false},
{SHA384WithRSA, "SHA384-RSA", oidSignatureSHA384WithRSA, asn1.NullRawValue, RSA, crypto.SHA384, false},
{SHA512WithRSA, "SHA512-RSA", oidSignatureSHA512WithRSA, asn1.NullRawValue, RSA, crypto.SHA512, false},
{SHA256WithRSAPSS, "SHA256-RSAPSS", oidSignatureRSAPSS, pssParametersSHA256, RSA, crypto.SHA256, true},
{SHA384WithRSAPSS, "SHA384-RSAPSS", oidSignatureRSAPSS, pssParametersSHA384, RSA, crypto.SHA384, true},
{SHA512WithRSAPSS, "SHA512-RSAPSS", oidSignatureRSAPSS, pssParametersSHA512, RSA, crypto.SHA512, true},
{DSAWithSHA1, "DSA-SHA1", oidSignatureDSAWithSHA1, emptyRawValue, DSA, crypto.SHA1, false},
{DSAWithSHA256, "DSA-SHA256", oidSignatureDSAWithSHA256, emptyRawValue, DSA, crypto.SHA256, false},
{ECDSAWithSHA1, "ECDSA-SHA1", oidSignatureECDSAWithSHA1, emptyRawValue, ECDSA, crypto.SHA1, false},
{ECDSAWithSHA256, "ECDSA-SHA256", oidSignatureECDSAWithSHA256, emptyRawValue, ECDSA, crypto.SHA256, false},
{ECDSAWithSHA384, "ECDSA-SHA384", oidSignatureECDSAWithSHA384, emptyRawValue, ECDSA, crypto.SHA384, false},
{ECDSAWithSHA512, "ECDSA-SHA512", oidSignatureECDSAWithSHA512, emptyRawValue, ECDSA, crypto.SHA512, false},
{PureEd25519, "Ed25519", oidSignatureEd25519, emptyRawValue, Ed25519, crypto.Hash(0) /* no pre-hashing */, false},
}
var emptyRawValue = asn1.RawValue{}
// DER encoded RSA PSS parameters for the
// SHA256, SHA384, and SHA512 hashes as defined in RFC 3447, Appendix A.2.3.
// The parameters contain the following values:
// - hashAlgorithm contains the associated hash identifier with NULL parameters
// - maskGenAlgorithm always contains the default mgf1SHA1 identifier
// - saltLength contains the length of the associated hash
// - trailerField always contains the default trailerFieldBC value
var (
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}}
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}}
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}}
)
// pssParameters reflects the parameters in an AlgorithmIdentifier that
// specifies RSA PSS. See RFC 3447, Appendix A.2.3.
type pssParameters struct {
// The following three fields are not marked as
// optional because the default values specify SHA-1,
// which is no longer suitable for use in signatures.
Hash pkix.AlgorithmIdentifier `asn1:"explicit,tag:0"`
MGF pkix.AlgorithmIdentifier `asn1:"explicit,tag:1"`
SaltLength int `asn1:"explicit,tag:2"`
TrailerField int `asn1:"optional,explicit,tag:3,default:1"`
}
func getSignatureAlgorithmFromAI(ai pkix.AlgorithmIdentifier) SignatureAlgorithm {
if ai.Algorithm.Equal(oidSignatureEd25519) {
// RFC 8410, Section 3
// > For all of the OIDs, the parameters MUST be absent.
if len(ai.Parameters.FullBytes) != 0 {
return UnknownSignatureAlgorithm
}
}
if !ai.Algorithm.Equal(oidSignatureRSAPSS) {
for _, details := range signatureAlgorithmDetails {
if ai.Algorithm.Equal(details.oid) {
return details.algo
}
}
return UnknownSignatureAlgorithm
}
// RSA PSS is special because it encodes important parameters
// in the Parameters.
var params pssParameters
if _, err := asn1.Unmarshal(ai.Parameters.FullBytes, ¶ms); err != nil {
return UnknownSignatureAlgorithm
}
var mgf1HashFunc pkix.AlgorithmIdentifier
if _, err := asn1.Unmarshal(params.MGF.Parameters.FullBytes, &mgf1HashFunc); err != nil {
return UnknownSignatureAlgorithm
}
// PSS is greatly overburdened with options. This code forces them into
// three buckets by requiring that the MGF1 hash function always match the
// message hash function (as recommended in RFC 3447, Section 8.1), that the
// salt length matches the hash length, and that the trailer field has the
// default value.
if (len(params.Hash.Parameters.FullBytes) != 0 && !bytes.Equal(params.Hash.Parameters.FullBytes, asn1.NullBytes)) ||
!params.MGF.Algorithm.Equal(oidMGF1) ||
!mgf1HashFunc.Algorithm.Equal(params.Hash.Algorithm) ||
(len(mgf1HashFunc.Parameters.FullBytes) != 0 && !bytes.Equal(mgf1HashFunc.Parameters.FullBytes, asn1.NullBytes)) ||
params.TrailerField != 1 {
return UnknownSignatureAlgorithm
}
switch {
case params.Hash.Algorithm.Equal(oidSHA256) && params.SaltLength == 32:
return SHA256WithRSAPSS
case params.Hash.Algorithm.Equal(oidSHA384) && params.SaltLength == 48:
return SHA384WithRSAPSS
case params.Hash.Algorithm.Equal(oidSHA512) && params.SaltLength == 64:
return SHA512WithRSAPSS
}
return UnknownSignatureAlgorithm
}
var (
// RFC 3279, 2.3 Public Key Algorithms
//
// pkcs-1 OBJECT IDENTIFIER ::== { iso(1) member-body(2) us(840)
// rsadsi(113549) pkcs(1) 1 }
//
// rsaEncryption OBJECT IDENTIFIER ::== { pkcs1-1 1 }
//
// id-dsa OBJECT IDENTIFIER ::== { iso(1) member-body(2) us(840)
// x9-57(10040) x9cm(4) 1 }
oidPublicKeyRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}
oidPublicKeyDSA = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 1}
// RFC 5480, 2.1.1 Unrestricted Algorithm Identifier and Parameters
//
// id-ecPublicKey OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 }
oidPublicKeyECDSA = asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}
// RFC 8410, Section 3
//
// id-X25519 OBJECT IDENTIFIER ::= { 1 3 101 110 }
// id-Ed25519 OBJECT IDENTIFIER ::= { 1 3 101 112 }
oidPublicKeyX25519 = asn1.ObjectIdentifier{1, 3, 101, 110}
oidPublicKeyEd25519 = asn1.ObjectIdentifier{1, 3, 101, 112}
)
// getPublicKeyAlgorithmFromOID returns the exposed PublicKeyAlgorithm
// identifier for public key types supported in certificates and CSRs. Marshal
// and Parse functions may support a different set of public key types.
func getPublicKeyAlgorithmFromOID(oid asn1.ObjectIdentifier) PublicKeyAlgorithm {
switch {
case oid.Equal(oidPublicKeyRSA):
return RSA
case oid.Equal(oidPublicKeyDSA):
return DSA
case oid.Equal(oidPublicKeyECDSA):
return ECDSA
case oid.Equal(oidPublicKeyEd25519):
return Ed25519
}
return UnknownPublicKeyAlgorithm
}
// RFC 5480, 2.1.1.1. Named Curve
//
// secp224r1 OBJECT IDENTIFIER ::= {
// iso(1) identified-organization(3) certicom(132) curve(0) 33 }
//
// secp256r1 OBJECT IDENTIFIER ::= {
// iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3)
// prime(1) 7 }
//
// secp384r1 OBJECT IDENTIFIER ::= {
// iso(1) identified-organization(3) certicom(132) curve(0) 34 }
//
// secp521r1 OBJECT IDENTIFIER ::= {
// iso(1) identified-organization(3) certicom(132) curve(0) 35 }
//
// NB: secp256r1 is equivalent to prime256v1
var (
oidNamedCurveP224 = asn1.ObjectIdentifier{1, 3, 132, 0, 33}
oidNamedCurveP256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 3, 1, 7}
oidNamedCurveP384 = asn1.ObjectIdentifier{1, 3, 132, 0, 34}
oidNamedCurveP521 = asn1.ObjectIdentifier{1, 3, 132, 0, 35}
)
func namedCurveFromOID(oid asn1.ObjectIdentifier) elliptic.Curve {
switch {
case oid.Equal(oidNamedCurveP224):
return elliptic.P224()
case oid.Equal(oidNamedCurveP256):
return elliptic.P256()
case oid.Equal(oidNamedCurveP384):
return elliptic.P384()
case oid.Equal(oidNamedCurveP521):
return elliptic.P521()
}
return nil
}
func oidFromNamedCurve(curve elliptic.Curve) (asn1.ObjectIdentifier, bool) {
switch curve {
case elliptic.P224():
return oidNamedCurveP224, true
case elliptic.P256():
return oidNamedCurveP256, true
case elliptic.P384():
return oidNamedCurveP384, true
case elliptic.P521():
return oidNamedCurveP521, true
}
return nil, false
}
func oidFromECDHCurve(curve ecdh.Curve) (asn1.ObjectIdentifier, bool) {
switch curve {
case ecdh.X25519():
return oidPublicKeyX25519, true
case ecdh.P256():
return oidNamedCurveP256, true
case ecdh.P384():
return oidNamedCurveP384, true
case ecdh.P521():
return oidNamedCurveP521, true
}
return nil, false
}
// KeyUsage represents the set of actions that are valid for a given key. It's
// a bitmap of the KeyUsage* constants.
type KeyUsage int
const (
KeyUsageDigitalSignature KeyUsage = 1 << iota
KeyUsageContentCommitment
KeyUsageKeyEncipherment
KeyUsageDataEncipherment
KeyUsageKeyAgreement
KeyUsageCertSign
KeyUsageCRLSign
KeyUsageEncipherOnly
KeyUsageDecipherOnly
)
// RFC 5280, 4.2.1.12 Extended Key Usage
//
// anyExtendedKeyUsage OBJECT IDENTIFIER ::= { id-ce-extKeyUsage 0 }
//
// id-kp OBJECT IDENTIFIER ::= { id-pkix 3 }
//
// id-kp-serverAuth OBJECT IDENTIFIER ::= { id-kp 1 }
// id-kp-clientAuth OBJECT IDENTIFIER ::= { id-kp 2 }
// id-kp-codeSigning OBJECT IDENTIFIER ::= { id-kp 3 }
// id-kp-emailProtection OBJECT IDENTIFIER ::= { id-kp 4 }
// id-kp-timeStamping OBJECT IDENTIFIER ::= { id-kp 8 }
// id-kp-OCSPSigning OBJECT IDENTIFIER ::= { id-kp 9 }
var (
oidExtKeyUsageAny = asn1.ObjectIdentifier{2, 5, 29, 37, 0}
oidExtKeyUsageServerAuth = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 1}
oidExtKeyUsageClientAuth = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 2}
oidExtKeyUsageCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 3}
oidExtKeyUsageEmailProtection = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 4}
oidExtKeyUsageIPSECEndSystem = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 5}
oidExtKeyUsageIPSECTunnel = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 6}
oidExtKeyUsageIPSECUser = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 7}
oidExtKeyUsageTimeStamping = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 8}
oidExtKeyUsageOCSPSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 9}
oidExtKeyUsageMicrosoftServerGatedCrypto = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 10, 3, 3}
oidExtKeyUsageNetscapeServerGatedCrypto = asn1.ObjectIdentifier{2, 16, 840, 1, 113730, 4, 1}
oidExtKeyUsageMicrosoftCommercialCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 2, 1, 22}
oidExtKeyUsageMicrosoftKernelCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 61, 1, 1}
)
// ExtKeyUsage represents an extended set of actions that are valid for a given key.
// Each of the ExtKeyUsage* constants define a unique action.
type ExtKeyUsage int
const (
ExtKeyUsageAny ExtKeyUsage = iota
ExtKeyUsageServerAuth
ExtKeyUsageClientAuth
ExtKeyUsageCodeSigning
ExtKeyUsageEmailProtection
ExtKeyUsageIPSECEndSystem
ExtKeyUsageIPSECTunnel
ExtKeyUsageIPSECUser
ExtKeyUsageTimeStamping
ExtKeyUsageOCSPSigning
ExtKeyUsageMicrosoftServerGatedCrypto
ExtKeyUsageNetscapeServerGatedCrypto
ExtKeyUsageMicrosoftCommercialCodeSigning
ExtKeyUsageMicrosoftKernelCodeSigning
)
// extKeyUsageOIDs contains the mapping between an ExtKeyUsage and its OID.
var extKeyUsageOIDs = []struct {
extKeyUsage ExtKeyUsage
oid asn1.ObjectIdentifier
}{
{ExtKeyUsageAny, oidExtKeyUsageAny},
{ExtKeyUsageServerAuth, oidExtKeyUsageServerAuth},
{ExtKeyUsageClientAuth, oidExtKeyUsageClientAuth},
{ExtKeyUsageCodeSigning, oidExtKeyUsageCodeSigning},
{ExtKeyUsageEmailProtection, oidExtKeyUsageEmailProtection},
{ExtKeyUsageIPSECEndSystem, oidExtKeyUsageIPSECEndSystem},
{ExtKeyUsageIPSECTunnel, oidExtKeyUsageIPSECTunnel},
{ExtKeyUsageIPSECUser, oidExtKeyUsageIPSECUser},
{ExtKeyUsageTimeStamping, oidExtKeyUsageTimeStamping},
{ExtKeyUsageOCSPSigning, oidExtKeyUsageOCSPSigning},
{ExtKeyUsageMicrosoftServerGatedCrypto, oidExtKeyUsageMicrosoftServerGatedCrypto},
{ExtKeyUsageNetscapeServerGatedCrypto, oidExtKeyUsageNetscapeServerGatedCrypto},
{ExtKeyUsageMicrosoftCommercialCodeSigning, oidExtKeyUsageMicrosoftCommercialCodeSigning},
{ExtKeyUsageMicrosoftKernelCodeSigning, oidExtKeyUsageMicrosoftKernelCodeSigning},
}
func extKeyUsageFromOID(oid asn1.ObjectIdentifier) (eku ExtKeyUsage, ok bool) {
for _, pair := range extKeyUsageOIDs {
if oid.Equal(pair.oid) {
return pair.extKeyUsage, true
}
}
return
}
func oidFromExtKeyUsage(eku ExtKeyUsage) (oid asn1.ObjectIdentifier, ok bool) {
for _, pair := range extKeyUsageOIDs {
if eku == pair.extKeyUsage {
return pair.oid, true
}
}
return
}
// A Certificate represents an X.509 certificate.
type Certificate struct {
Raw []byte // Complete ASN.1 DER content (certificate, signature algorithm and signature).
RawTBSCertificate []byte // Certificate part of raw ASN.1 DER content.
RawSubjectPublicKeyInfo []byte // DER encoded SubjectPublicKeyInfo.
RawSubject []byte // DER encoded Subject
RawIssuer []byte // DER encoded Issuer
Signature []byte
SignatureAlgorithm SignatureAlgorithm
PublicKeyAlgorithm PublicKeyAlgorithm
PublicKey any
Version int
SerialNumber *big.Int
Issuer pkix.Name
Subject pkix.Name
NotBefore, NotAfter time.Time // Validity bounds.
KeyUsage KeyUsage
// Extensions contains raw X.509 extensions. When parsing certificates,
// this can be used to extract non-critical extensions that are not
// parsed by this package. When marshaling certificates, the Extensions
// field is ignored, see ExtraExtensions.
Extensions []pkix.Extension
// ExtraExtensions contains extensions to be copied, raw, into any
// marshaled certificates. Values override any extensions that would
// otherwise be produced based on the other fields. The ExtraExtensions
// field is not populated when parsing certificates, see Extensions.
ExtraExtensions []pkix.Extension
// UnhandledCriticalExtensions contains a list of extension IDs that
// were not (fully) processed when parsing. Verify will fail if this
// slice is non-empty, unless verification is delegated to an OS
// library which understands all the critical extensions.
//
// Users can access these extensions using Extensions and can remove
// elements from this slice if they believe that they have been
// handled.
UnhandledCriticalExtensions []asn1.ObjectIdentifier
ExtKeyUsage []ExtKeyUsage // Sequence of extended key usages.
UnknownExtKeyUsage []asn1.ObjectIdentifier // Encountered extended key usages unknown to this package.
// BasicConstraintsValid indicates whether IsCA, MaxPathLen,
// and MaxPathLenZero are valid.
BasicConstraintsValid bool
IsCA bool
// MaxPathLen and MaxPathLenZero indicate the presence and
// value of the BasicConstraints' "pathLenConstraint".
//
// When parsing a certificate, a positive non-zero MaxPathLen
// means that the field was specified, -1 means it was unset,
// and MaxPathLenZero being true mean that the field was
// explicitly set to zero. The case of MaxPathLen==0 with MaxPathLenZero==false
// should be treated equivalent to -1 (unset).
//
// When generating a certificate, an unset pathLenConstraint
// can be requested with either MaxPathLen == -1 or using the
// zero value for both MaxPathLen and MaxPathLenZero.
MaxPathLen int
// MaxPathLenZero indicates that BasicConstraintsValid==true
// and MaxPathLen==0 should be interpreted as an actual
// maximum path length of zero. Otherwise, that combination is
// interpreted as MaxPathLen not being set.
MaxPathLenZero bool
SubjectKeyId []byte
AuthorityKeyId []byte
// RFC 5280, 4.2.2.1 (Authority Information Access)
OCSPServer []string
IssuingCertificateURL []string
// Subject Alternate Name values. (Note that these values may not be valid
// if invalid values were contained within a parsed certificate. For
// example, an element of DNSNames may not be a valid DNS domain name.)
DNSNames []string
EmailAddresses []string
IPAddresses []net.IP
URIs []*url.URL
// Name constraints
PermittedDNSDomainsCritical bool // if true then the name constraints are marked critical.
PermittedDNSDomains []string
ExcludedDNSDomains []string
PermittedIPRanges []*net.IPNet
ExcludedIPRanges []*net.IPNet
PermittedEmailAddresses []string
ExcludedEmailAddresses []string
PermittedURIDomains []string
ExcludedURIDomains []string
// CRL Distribution Points
CRLDistributionPoints []string
// PolicyIdentifiers contains asn1.ObjectIdentifiers, the components
// of which are limited to int32. If a certificate contains a policy which
// cannot be represented by asn1.ObjectIdentifier, it will not be included in
// PolicyIdentifiers, but will be present in Policies, which contains all parsed
// policy OIDs.
// See CreateCertificate for context about how this field and the Policies field
// interact.
PolicyIdentifiers []asn1.ObjectIdentifier
// Policies contains all policy identifiers included in the certificate.
// See CreateCertificate for context about how this field and the PolicyIdentifiers field
// interact.
// In Go 1.22, encoding/gob cannot handle and ignores this field.
Policies []OID
// InhibitAnyPolicy and InhibitAnyPolicyZero indicate the presence and value
// of the inhibitAnyPolicy extension.
//
// The value of InhibitAnyPolicy indicates the number of additional
// certificates in the path after this certificate that may use the
// anyPolicy policy OID to indicate a match with any other policy.
//
// When parsing a certificate, a positive non-zero InhibitAnyPolicy means
// that the field was specified, -1 means it was unset, and
// InhibitAnyPolicyZero being true mean that the field was explicitly set to
// zero. The case of InhibitAnyPolicy==0 with InhibitAnyPolicyZero==false
// should be treated equivalent to -1 (unset).
InhibitAnyPolicy int
// InhibitAnyPolicyZero indicates that InhibitAnyPolicy==0 should be
// interpreted as an actual maximum path length of zero. Otherwise, that
// combination is interpreted as InhibitAnyPolicy not being set.
InhibitAnyPolicyZero bool
// InhibitPolicyMapping and InhibitPolicyMappingZero indicate the presence
// and value of the inhibitPolicyMapping field of the policyConstraints
// extension.
//
// The value of InhibitPolicyMapping indicates the number of additional
// certificates in the path after this certificate that may use policy
// mapping.
//
// When parsing a certificate, a positive non-zero InhibitPolicyMapping
// means that the field was specified, -1 means it was unset, and
// InhibitPolicyMappingZero being true mean that the field was explicitly
// set to zero. The case of InhibitPolicyMapping==0 with
// InhibitPolicyMappingZero==false should be treated equivalent to -1
// (unset).
InhibitPolicyMapping int
// InhibitPolicyMappingZero indicates that InhibitPolicyMapping==0 should be
// interpreted as an actual maximum path length of zero. Otherwise, that
// combination is interpreted as InhibitAnyPolicy not being set.
InhibitPolicyMappingZero bool
// RequireExplicitPolicy and RequireExplicitPolicyZero indicate the presence
// and value of the requireExplicitPolicy field of the policyConstraints
// extension.
//
// The value of RequireExplicitPolicy indicates the number of additional
// certificates in the path after this certificate before an explicit policy
// is required for the rest of the path. When an explicit policy is required,
// each subsequent certificate in the path must contain a required policy OID,
// or a policy OID which has been declared as equivalent through the policy
// mapping extension.
//
// When parsing a certificate, a positive non-zero RequireExplicitPolicy
// means that the field was specified, -1 means it was unset, and
// RequireExplicitPolicyZero being true mean that the field was explicitly
// set to zero. The case of RequireExplicitPolicy==0 with
// RequireExplicitPolicyZero==false should be treated equivalent to -1
// (unset).
RequireExplicitPolicy int
// RequireExplicitPolicyZero indicates that RequireExplicitPolicy==0 should be
// interpreted as an actual maximum path length of zero. Otherwise, that
// combination is interpreted as InhibitAnyPolicy not being set.
RequireExplicitPolicyZero bool
// PolicyMappings contains a list of policy mappings included in the certificate.
PolicyMappings []PolicyMapping
}
// PolicyMapping represents a policy mapping entry in the policyMappings extension.
type PolicyMapping struct {
// IssuerDomainPolicy contains a policy OID the issuing certificate considers
// equivalent to SubjectDomainPolicy in the subject certificate.
IssuerDomainPolicy OID
// SubjectDomainPolicy contains a OID the issuing certificate considers
// equivalent to IssuerDomainPolicy in the subject certificate.
SubjectDomainPolicy OID
}
// ErrUnsupportedAlgorithm results from attempting to perform an operation that
// involves algorithms that are not currently implemented.
var ErrUnsupportedAlgorithm = errors.New("x509: cannot verify signature: algorithm unimplemented")
// An InsecureAlgorithmError indicates that the [SignatureAlgorithm] used to
// generate the signature is not secure, and the signature has been rejected.
type InsecureAlgorithmError SignatureAlgorithm
func (e InsecureAlgorithmError) Error() string {
return fmt.Sprintf("x509: cannot verify signature: insecure algorithm %v", SignatureAlgorithm(e))
}
// ConstraintViolationError results when a requested usage is not permitted by
// a certificate. For example: checking a signature when the public key isn't a
// certificate signing key.
type ConstraintViolationError struct{}
func (ConstraintViolationError) Error() string {
return "x509: invalid signature: parent certificate cannot sign this kind of certificate"
}
func (c *Certificate) Equal(other *Certificate) bool {
if c == nil || other == nil {
return c == other
}
return bytes.Equal(c.Raw, other.Raw)
}
func (c *Certificate) hasSANExtension() bool {
return oidInExtensions(oidExtensionSubjectAltName, c.Extensions)
}
// CheckSignatureFrom verifies that the signature on c is a valid signature from parent.
//
// This is a low-level API that performs very limited checks, and not a full
// path verifier. Most users should use [Certificate.Verify] instead.
func (c *Certificate) CheckSignatureFrom(parent *Certificate) error {
// RFC 5280, 4.2.1.9:
// "If the basic constraints extension is not present in a version 3
// certificate, or the extension is present but the cA boolean is not
// asserted, then the certified public key MUST NOT be used to verify
// certificate signatures."
if parent.Version == 3 && !parent.BasicConstraintsValid ||
parent.BasicConstraintsValid && !parent.IsCA {
return ConstraintViolationError{}
}
if parent.KeyUsage != 0 && parent.KeyUsage&KeyUsageCertSign == 0 {
return ConstraintViolationError{}
}
if parent.PublicKeyAlgorithm == UnknownPublicKeyAlgorithm {
return ErrUnsupportedAlgorithm
}
return checkSignature(c.SignatureAlgorithm, c.RawTBSCertificate, c.Signature, parent.PublicKey, false)
}
// CheckSignature verifies that signature is a valid signature over signed from
// c's public key.
//
// This is a low-level API that performs no validity checks on the certificate.
//
// [MD5WithRSA] signatures are rejected, while [SHA1WithRSA] and [ECDSAWithSHA1]
// signatures are currently accepted.
func (c *Certificate) CheckSignature(algo SignatureAlgorithm, signed, signature []byte) error {
return checkSignature(algo, signed, signature, c.PublicKey, true)
}
func (c *Certificate) hasNameConstraints() bool {
return oidInExtensions(oidExtensionNameConstraints, c.Extensions)
}
func (c *Certificate) getSANExtension() []byte {
for _, e := range c.Extensions {
if e.Id.Equal(oidExtensionSubjectAltName) {
return e.Value
}
}
return nil
}
func signaturePublicKeyAlgoMismatchError(expectedPubKeyAlgo PublicKeyAlgorithm, pubKey any) error {
return fmt.Errorf("x509: signature algorithm specifies an %s public key, but have public key of type %T", expectedPubKeyAlgo.String(), pubKey)
}
// checkSignature verifies that signature is a valid signature over signed from
// a crypto.PublicKey.
func checkSignature(algo SignatureAlgorithm, signed, signature []byte, publicKey crypto.PublicKey, allowSHA1 bool) (err error) {
var hashType crypto.Hash
var pubKeyAlgo PublicKeyAlgorithm
for _, details := range signatureAlgorithmDetails {
if details.algo == algo {
hashType = details.hash
pubKeyAlgo = details.pubKeyAlgo
break
}
}
switch hashType {
case crypto.Hash(0):
if pubKeyAlgo != Ed25519 {
return ErrUnsupportedAlgorithm
}
case crypto.MD5:
return InsecureAlgorithmError(algo)
case crypto.SHA1:
// SHA-1 signatures are only allowed for CRLs and CSRs.
if !allowSHA1 {
return InsecureAlgorithmError(algo)
}
fallthrough
default:
if !hashType.Available() {
return ErrUnsupportedAlgorithm
}
h := hashType.New()
h.Write(signed)
signed = h.Sum(nil)
}
switch pub := publicKey.(type) {
case *rsa.PublicKey:
if pubKeyAlgo != RSA {
return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)
}
if algo.isRSAPSS() {
return rsa.VerifyPSS(pub, hashType, signed, signature, &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash})
} else {
return rsa.VerifyPKCS1v15(pub, hashType, signed, signature)
}
case *ecdsa.PublicKey:
if pubKeyAlgo != ECDSA {
return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)
}
if !ecdsa.VerifyASN1(pub, signed, signature) {
return errors.New("x509: ECDSA verification failure")
}
return
case ed25519.PublicKey:
if pubKeyAlgo != Ed25519 {
return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)
}
if !ed25519.Verify(pub, signed, signature) {
return errors.New("x509: Ed25519 verification failure")
}
return
}
return ErrUnsupportedAlgorithm
}
// CheckCRLSignature checks that the signature in crl is from c.
//
// Deprecated: Use [RevocationList.CheckSignatureFrom] instead.
func (c *Certificate) CheckCRLSignature(crl *pkix.CertificateList) error {
algo := getSignatureAlgorithmFromAI(crl.SignatureAlgorithm)
return c.CheckSignature(algo, crl.TBSCertList.Raw, crl.SignatureValue.RightAlign())
}
type UnhandledCriticalExtension struct{}
func (h UnhandledCriticalExtension) Error() string {
return "x509: unhandled critical extension"
}
type basicConstraints struct {
IsCA bool `asn1:"optional"`
MaxPathLen int `asn1:"optional,default:-1"`
}
// RFC 5280 4.2.1.4
type policyInformation struct {
Policy asn1.ObjectIdentifier
// policyQualifiers omitted
}
const (
nameTypeEmail = 1
nameTypeDNS = 2
nameTypeURI = 6
nameTypeIP = 7
)
// RFC 5280, 4.2.2.1
type authorityInfoAccess struct {
Method asn1.ObjectIdentifier
Location asn1.RawValue
}
// RFC 5280, 4.2.1.14
type distributionPoint struct {
DistributionPoint distributionPointName `asn1:"optional,tag:0"`
Reason asn1.BitString `asn1:"optional,tag:1"`
CRLIssuer asn1.RawValue `asn1:"optional,tag:2"`
}
type distributionPointName struct {
FullName []asn1.RawValue `asn1:"optional,tag:0"`
RelativeName pkix.RDNSequence `asn1:"optional,tag:1"`
}
func reverseBitsInAByte(in byte) byte {
b1 := in>>4 | in<<4
b2 := b1>>2&0x33 | b1<<2&0xcc
b3 := b2>>1&0x55 | b2<<1&0xaa
return b3
}
// asn1BitLength returns the bit-length of bitString by considering the
// most-significant bit in a byte to be the "first" bit. This convention
// matches ASN.1, but differs from almost everything else.
func asn1BitLength(bitString []byte) int {
bitLen := len(bitString) * 8
for i := range bitString {
b := bitString[len(bitString)-i-1]
for bit := uint(0); bit < 8; bit++ {
if (b>>bit)&1 == 1 {
return bitLen
}
bitLen--
}
}
return 0
}
var (
oidExtensionSubjectKeyId = []int{2, 5, 29, 14}
oidExtensionKeyUsage = []int{2, 5, 29, 15}
oidExtensionExtendedKeyUsage = []int{2, 5, 29, 37}
oidExtensionAuthorityKeyId = []int{2, 5, 29, 35}
oidExtensionBasicConstraints = []int{2, 5, 29, 19}
oidExtensionSubjectAltName = []int{2, 5, 29, 17}
oidExtensionCertificatePolicies = []int{2, 5, 29, 32}
oidExtensionNameConstraints = []int{2, 5, 29, 30}
oidExtensionCRLDistributionPoints = []int{2, 5, 29, 31}
oidExtensionAuthorityInfoAccess = []int{1, 3, 6, 1, 5, 5, 7, 1, 1}
oidExtensionCRLNumber = []int{2, 5, 29, 20}
oidExtensionReasonCode = []int{2, 5, 29, 21}
)
var (
oidAuthorityInfoAccessOcsp = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 1}
oidAuthorityInfoAccessIssuers = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 2}
)
// oidInExtensions reports whether an extension with the given oid exists in
// extensions.
func oidInExtensions(oid asn1.ObjectIdentifier, extensions []pkix.Extension) bool {
for _, e := range extensions {
if e.Id.Equal(oid) {
return true
}
}
return false
}
// marshalSANs marshals a list of addresses into a the contents of an X.509
// SubjectAlternativeName extension.
func marshalSANs(dnsNames, emailAddresses []string, ipAddresses []net.IP, uris []*url.URL) (derBytes []byte, err error) {
var rawValues []asn1.RawValue
for _, name := range dnsNames {
if err := isIA5String(name); err != nil {
return nil, err
}
rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeDNS, Class: 2, Bytes: []byte(name)})
}
for _, email := range emailAddresses {
if err := isIA5String(email); err != nil {
return nil, err
}
rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeEmail, Class: 2, Bytes: []byte(email)})
}
for _, rawIP := range ipAddresses {
// If possible, we always want to encode IPv4 addresses in 4 bytes.
ip := rawIP.To4()
if ip == nil {
ip = rawIP
}
rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeIP, Class: 2, Bytes: ip})
}
for _, uri := range uris {
uriStr := uri.String()
if err := isIA5String(uriStr); err != nil {
return nil, err
}
rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeURI, Class: 2, Bytes: []byte(uriStr)})
}
return asn1.Marshal(rawValues)
}
func isIA5String(s string) error {
for _, r := range s {
// Per RFC5280 "IA5String is limited to the set of ASCII characters"
if r > unicode.MaxASCII {
return fmt.Errorf("x509: %q cannot be encoded as an IA5String", s)
}
}
return nil
}
var x509usepolicies = godebug.New("x509usepolicies")
func buildCertExtensions(template *Certificate, subjectIsEmpty bool, authorityKeyId []byte, subjectKeyId []byte) (ret []pkix.Extension, err error) {
ret = make([]pkix.Extension, 10 /* maximum number of elements. */)
n := 0
if template.KeyUsage != 0 &&
!oidInExtensions(oidExtensionKeyUsage, template.ExtraExtensions) {
ret[n], err = marshalKeyUsage(template.KeyUsage)
if err != nil {
return nil, err
}
n++
}
if (len(template.ExtKeyUsage) > 0 || len(template.UnknownExtKeyUsage) > 0) &&
!oidInExtensions(oidExtensionExtendedKeyUsage, template.ExtraExtensions) {
ret[n], err = marshalExtKeyUsage(template.ExtKeyUsage, template.UnknownExtKeyUsage)
if err != nil {
return nil, err
}
n++
}
if template.BasicConstraintsValid && !oidInExtensions(oidExtensionBasicConstraints, template.ExtraExtensions) {
ret[n], err = marshalBasicConstraints(template.IsCA, template.MaxPathLen, template.MaxPathLenZero)
if err != nil {
return nil, err
}
n++
}
if len(subjectKeyId) > 0 && !oidInExtensions(oidExtensionSubjectKeyId, template.ExtraExtensions) {
ret[n].Id = oidExtensionSubjectKeyId
ret[n].Value, err = asn1.Marshal(subjectKeyId)
if err != nil {
return
}
n++
}
if len(authorityKeyId) > 0 && !oidInExtensions(oidExtensionAuthorityKeyId, template.ExtraExtensions) {
ret[n].Id = oidExtensionAuthorityKeyId
ret[n].Value, err = asn1.Marshal(authKeyId{authorityKeyId})
if err != nil {
return
}
n++
}
if (len(template.OCSPServer) > 0 || len(template.IssuingCertificateURL) > 0) &&
!oidInExtensions(oidExtensionAuthorityInfoAccess, template.ExtraExtensions) {
ret[n].Id = oidExtensionAuthorityInfoAccess
var aiaValues []authorityInfoAccess
for _, name := range template.OCSPServer {
aiaValues = append(aiaValues, authorityInfoAccess{
Method: oidAuthorityInfoAccessOcsp,
Location: asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)},
})
}
for _, name := range template.IssuingCertificateURL {
aiaValues = append(aiaValues, authorityInfoAccess{
Method: oidAuthorityInfoAccessIssuers,
Location: asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)},
})
}
ret[n].Value, err = asn1.Marshal(aiaValues)
if err != nil {
return
}
n++
}
if (len(template.DNSNames) > 0 || len(template.EmailAddresses) > 0 || len(template.IPAddresses) > 0 || len(template.URIs) > 0) &&
!oidInExtensions(oidExtensionSubjectAltName, template.ExtraExtensions) {
ret[n].Id = oidExtensionSubjectAltName
// From RFC 5280, Section 4.2.1.6:
// “If the subject field contains an empty sequence ... then
// subjectAltName extension ... is marked as critical”
ret[n].Critical = subjectIsEmpty
ret[n].Value, err = marshalSANs(template.DNSNames, template.EmailAddresses, template.IPAddresses, template.URIs)
if err != nil {
return
}
n++
}
usePolicies := x509usepolicies.Value() != "0"
if ((!usePolicies && len(template.PolicyIdentifiers) > 0) || (usePolicies && len(template.Policies) > 0)) &&
!oidInExtensions(oidExtensionCertificatePolicies, template.ExtraExtensions) {
ret[n], err = marshalCertificatePolicies(template.Policies, template.PolicyIdentifiers)
if err != nil {
return nil, err
}
n++
}
if (len(template.PermittedDNSDomains) > 0 || len(template.ExcludedDNSDomains) > 0 ||
len(template.PermittedIPRanges) > 0 || len(template.ExcludedIPRanges) > 0 ||
len(template.PermittedEmailAddresses) > 0 || len(template.ExcludedEmailAddresses) > 0 ||
len(template.PermittedURIDomains) > 0 || len(template.ExcludedURIDomains) > 0) &&
!oidInExtensions(oidExtensionNameConstraints, template.ExtraExtensions) {
ret[n].Id = oidExtensionNameConstraints
ret[n].Critical = template.PermittedDNSDomainsCritical
ipAndMask := func(ipNet *net.IPNet) []byte {
maskedIP := ipNet.IP.Mask(ipNet.Mask)
ipAndMask := make([]byte, 0, len(maskedIP)+len(ipNet.Mask))
ipAndMask = append(ipAndMask, maskedIP...)
ipAndMask = append(ipAndMask, ipNet.Mask...)
return ipAndMask
}
serialiseConstraints := func(dns []string, ips []*net.IPNet, emails []string, uriDomains []string) (der []byte, err error) {
var b cryptobyte.Builder
for _, name := range dns {
if err = isIA5String(name); err != nil {
return nil, err
}
b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
b.AddASN1(cryptobyte_asn1.Tag(2).ContextSpecific(), func(b *cryptobyte.Builder) {
b.AddBytes([]byte(name))
})
})
}
for _, ipNet := range ips {
b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
b.AddASN1(cryptobyte_asn1.Tag(7).ContextSpecific(), func(b *cryptobyte.Builder) {
b.AddBytes(ipAndMask(ipNet))
})
})
}
for _, email := range emails {
if err = isIA5String(email); err != nil {
return nil, err
}
b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
b.AddASN1(cryptobyte_asn1.Tag(1).ContextSpecific(), func(b *cryptobyte.Builder) {
b.AddBytes([]byte(email))
})
})
}
for _, uriDomain := range uriDomains {
if err = isIA5String(uriDomain); err != nil {
return nil, err
}
b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
b.AddASN1(cryptobyte_asn1.Tag(6).ContextSpecific(), func(b *cryptobyte.Builder) {
b.AddBytes([]byte(uriDomain))
})
})
}
return b.Bytes()
}
permitted, err := serialiseConstraints(template.PermittedDNSDomains, template.PermittedIPRanges, template.PermittedEmailAddresses, template.PermittedURIDomains)
if err != nil {
return nil, err
}
excluded, err := serialiseConstraints(template.ExcludedDNSDomains, template.ExcludedIPRanges, template.ExcludedEmailAddresses, template.ExcludedURIDomains)
if err != nil {
return nil, err
}
var b cryptobyte.Builder
b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
if len(permitted) > 0 {
b.AddASN1(cryptobyte_asn1.Tag(0).ContextSpecific().Constructed(), func(b *cryptobyte.Builder) {
b.AddBytes(permitted)
})
}
if len(excluded) > 0 {
b.AddASN1(cryptobyte_asn1.Tag(1).ContextSpecific().Constructed(), func(b *cryptobyte.Builder) {
b.AddBytes(excluded)
})
}
})
ret[n].Value, err = b.Bytes()
if err != nil {
return nil, err
}
n++
}
if len(template.CRLDistributionPoints) > 0 &&
!oidInExtensions(oidExtensionCRLDistributionPoints, template.ExtraExtensions) {
ret[n].Id = oidExtensionCRLDistributionPoints
var crlDp []distributionPoint
for _, name := range template.CRLDistributionPoints {
dp := distributionPoint{
DistributionPoint: distributionPointName{
FullName: []asn1.RawValue{
{Tag: 6, Class: 2, Bytes: []byte(name)},
},
},
}
crlDp = append(crlDp, dp)
}
ret[n].Value, err = asn1.Marshal(crlDp)
if err != nil {
return
}
n++
}
// Adding another extension here? Remember to update the maximum number
// of elements in the make() at the top of the function and the list of
// template fields used in CreateCertificate documentation.
return append(ret[:n], template.ExtraExtensions...), nil
}
func marshalKeyUsage(ku KeyUsage) (pkix.Extension, error) {
ext := pkix.Extension{Id: oidExtensionKeyUsage, Critical: true}
var a [2]byte
a[0] = reverseBitsInAByte(byte(ku))
a[1] = reverseBitsInAByte(byte(ku >> 8))
l := 1
if a[1] != 0 {
l = 2
}
bitString := a[:l]
var err error
ext.Value, err = asn1.Marshal(asn1.BitString{Bytes: bitString, BitLength: asn1BitLength(bitString)})
return ext, err
}
func marshalExtKeyUsage(extUsages []ExtKeyUsage, unknownUsages []asn1.ObjectIdentifier) (pkix.Extension, error) {
ext := pkix.Extension{Id: oidExtensionExtendedKeyUsage}
oids := make([]asn1.ObjectIdentifier, len(extUsages)+len(unknownUsages))
for i, u := range extUsages {
if oid, ok := oidFromExtKeyUsage(u); ok {
oids[i] = oid
} else {
return ext, errors.New("x509: unknown extended key usage")
}
}
copy(oids[len(extUsages):], unknownUsages)
var err error
ext.Value, err = asn1.Marshal(oids)
return ext, err
}
func marshalBasicConstraints(isCA bool, maxPathLen int, maxPathLenZero bool) (pkix.Extension, error) {
ext := pkix.Extension{Id: oidExtensionBasicConstraints, Critical: true}
// Leaving MaxPathLen as zero indicates that no maximum path
// length is desired, unless MaxPathLenZero is set. A value of
// -1 causes encoding/asn1 to omit the value as desired.
if maxPathLen == 0 && !maxPathLenZero {
maxPathLen = -1
}
var err error
ext.Value, err = asn1.Marshal(basicConstraints{isCA, maxPathLen})
return ext, err
}
func marshalCertificatePolicies(policies []OID, policyIdentifiers []asn1.ObjectIdentifier) (pkix.Extension, error) {
ext := pkix.Extension{Id: oidExtensionCertificatePolicies}
b := cryptobyte.NewBuilder(make([]byte, 0, 128))
b.AddASN1(cryptobyte_asn1.SEQUENCE, func(child *cryptobyte.Builder) {
if x509usepolicies.Value() != "0" {
x509usepolicies.IncNonDefault()
for _, v := range policies {
child.AddASN1(cryptobyte_asn1.SEQUENCE, func(child *cryptobyte.Builder) {
child.AddASN1(cryptobyte_asn1.OBJECT_IDENTIFIER, func(child *cryptobyte.Builder) {
if len(v.der) == 0 {
child.SetError(errors.New("invalid policy object identifier"))
return
}
child.AddBytes(v.der)
})
})
}
} else {
for _, v := range policyIdentifiers {
child.AddASN1(cryptobyte_asn1.SEQUENCE, func(child *cryptobyte.Builder) {
child.AddASN1ObjectIdentifier(v)
})
}
}
})
var err error
ext.Value, err = b.Bytes()
return ext, err
}
func buildCSRExtensions(template *CertificateRequest) ([]pkix.Extension, error) {
var ret []pkix.Extension
if (len(template.DNSNames) > 0 || len(template.EmailAddresses) > 0 || len(template.IPAddresses) > 0 || len(template.URIs) > 0) &&
!oidInExtensions(oidExtensionSubjectAltName, template.ExtraExtensions) {
sanBytes, err := marshalSANs(template.DNSNames, template.EmailAddresses, template.IPAddresses, template.URIs)
if err != nil {
return nil, err
}
ret = append(ret, pkix.Extension{
Id: oidExtensionSubjectAltName,
Value: sanBytes,
})
}
return append(ret, template.ExtraExtensions...), nil
}
func subjectBytes(cert *Certificate) ([]byte, error) {
if len(cert.RawSubject) > 0 {
return cert.RawSubject, nil
}
return asn1.Marshal(cert.Subject.ToRDNSequence())
}
// signingParamsForKey returns the signature algorithm and its Algorithm
// Identifier to use for signing, based on the key type. If sigAlgo is not zero
// then it overrides the default.
func signingParamsForKey(key crypto.Signer, sigAlgo SignatureAlgorithm) (SignatureAlgorithm, pkix.AlgorithmIdentifier, error) {
var ai pkix.AlgorithmIdentifier
var pubType PublicKeyAlgorithm
var defaultAlgo SignatureAlgorithm
switch pub := key.Public().(type) {
case *rsa.PublicKey:
pubType = RSA
defaultAlgo = SHA256WithRSA
case *ecdsa.PublicKey:
pubType = ECDSA
switch pub.Curve {
case elliptic.P224(), elliptic.P256():
defaultAlgo = ECDSAWithSHA256
case elliptic.P384():
defaultAlgo = ECDSAWithSHA384
case elliptic.P521():
defaultAlgo = ECDSAWithSHA512
default:
return 0, ai, errors.New("x509: unsupported elliptic curve")
}
case ed25519.PublicKey:
pubType = Ed25519
defaultAlgo = PureEd25519
default:
return 0, ai, errors.New("x509: only RSA, ECDSA and Ed25519 keys supported")
}
if sigAlgo == 0 {
sigAlgo = defaultAlgo
}
for _, details := range signatureAlgorithmDetails {
if details.algo == sigAlgo {
if details.pubKeyAlgo != pubType {
return 0, ai, errors.New("x509: requested SignatureAlgorithm does not match private key type")
}
if details.hash == crypto.MD5 {
return 0, ai, errors.New("x509: signing with MD5 is not supported")
}
return sigAlgo, pkix.AlgorithmIdentifier{
Algorithm: details.oid,
Parameters: details.params,
}, nil
}
}
return 0, ai, errors.New("x509: unknown SignatureAlgorithm")
}
func signTBS(tbs []byte, key crypto.Signer, sigAlg SignatureAlgorithm, rand io.Reader) ([]byte, error) {
signed := tbs
hashFunc := sigAlg.hashFunc()
if hashFunc != 0 {
h := hashFunc.New()
h.Write(signed)
signed = h.Sum(nil)
}
var signerOpts crypto.SignerOpts = hashFunc
if sigAlg.isRSAPSS() {
signerOpts = &rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthEqualsHash,
Hash: hashFunc,
}
}
signature, err := key.Sign(rand, signed, signerOpts)
if err != nil {
return nil, err
}
// Check the signature to ensure the crypto.Signer behaved correctly.
if err := checkSignature(sigAlg, tbs, signature, key.Public(), true); err != nil {
return nil, fmt.Errorf("x509: signature returned by signer is invalid: %w", err)
}
return signature, nil
}
// emptyASN1Subject is the ASN.1 DER encoding of an empty Subject, which is
// just an empty SEQUENCE.
var emptyASN1Subject = []byte{0x30, 0}
// CreateCertificate creates a new X.509 v3 certificate based on a template.
// The following members of template are currently used:
//
// - AuthorityKeyId
// - BasicConstraintsValid
// - CRLDistributionPoints
// - DNSNames
// - EmailAddresses
// - ExcludedDNSDomains
// - ExcludedEmailAddresses
// - ExcludedIPRanges
// - ExcludedURIDomains
// - ExtKeyUsage
// - ExtraExtensions
// - IPAddresses
// - IsCA
// - IssuingCertificateURL
// - KeyUsage
// - MaxPathLen
// - MaxPathLenZero
// - NotAfter
// - NotBefore
// - OCSPServer
// - PermittedDNSDomains
// - PermittedDNSDomainsCritical
// - PermittedEmailAddresses
// - PermittedIPRanges
// - PermittedURIDomains
// - PolicyIdentifiers (see note below)
// - Policies (see note below)
// - SerialNumber
// - SignatureAlgorithm
// - Subject
// - SubjectKeyId
// - URIs
// - UnknownExtKeyUsage
//
// The certificate is signed by parent. If parent is equal to template then the
// certificate is self-signed. The parameter pub is the public key of the
// certificate to be generated and priv is the private key of the signer.
//
// The returned slice is the certificate in DER encoding.
//
// The currently supported key types are *rsa.PublicKey, *ecdsa.PublicKey and
// ed25519.PublicKey. pub must be a supported key type, and priv must be a
// crypto.Signer with a supported public key.
//
// The AuthorityKeyId will be taken from the SubjectKeyId of parent, if any,
// unless the resulting certificate is self-signed. Otherwise the value from
// template will be used.
//
// If SubjectKeyId from template is empty and the template is a CA, SubjectKeyId
// will be generated from the hash of the public key.
//
// If template.SerialNumber is nil, a serial number will be generated which
// conforms to RFC 5280, Section 4.1.2.2 using entropy from rand.
//
// The PolicyIdentifier and Policies fields can both be used to marshal certificate
// policy OIDs. By default, only the Policies is marshaled, but if the
// GODEBUG setting "x509usepolicies" has the value "0", the PolicyIdentifiers field will
// be marshaled instead of the Policies field. This changed in Go 1.24. The Policies field can
// be used to marshal policy OIDs which have components that are larger than 31
// bits.
func CreateCertificate(rand io.Reader, template, parent *Certificate, pub, priv any) ([]byte, error) {
key, ok := priv.(crypto.Signer)
if !ok {
return nil, errors.New("x509: certificate private key does not implement crypto.Signer")
}
serialNumber := template.SerialNumber
if serialNumber == nil {
// Generate a serial number following RFC 5280 Section 4.1.2.2 if one is not provided.
// Requirements:
// - serial number must be positive
// - at most 20 octets when encoded
maxSerial := big.NewInt(1).Lsh(big.NewInt(1), 20*8)
for {
var err error
serialNumber, err = cryptorand.Int(rand, maxSerial)
if err != nil {
return nil, err
}
// If the serial is exactly 20 octets, check if the high bit of the first byte is set.
// If so, generate a new serial, since it will be padded with a leading 0 byte during
// encoding so that the serial is not interpreted as a negative integer, making it
// 21 octets.
if serialBytes := serialNumber.Bytes(); len(serialBytes) > 0 && (len(serialBytes) < 20 || serialBytes[0]&0x80 == 0) {
break
}
}
}
// RFC 5280 Section 4.1.2.2: serial number must be positive
//
// We _should_ also restrict serials to <= 20 octets, but it turns out a lot of people
// get this wrong, in part because the encoding can itself alter the length of the
// serial. For now we accept these non-conformant serials.
if serialNumber.Sign() == -1 {
return nil, errors.New("x509: serial number must be positive")
}
if template.BasicConstraintsValid && !template.IsCA && template.MaxPathLen != -1 && (template.MaxPathLen != 0 || template.MaxPathLenZero) {
return nil, errors.New("x509: only CAs are allowed to specify MaxPathLen")
}
signatureAlgorithm, algorithmIdentifier, err := signingParamsForKey(key, template.SignatureAlgorithm)
if err != nil {
return nil, err
}
publicKeyBytes, publicKeyAlgorithm, err := marshalPublicKey(pub)
if err != nil {
return nil, err
}
if getPublicKeyAlgorithmFromOID(publicKeyAlgorithm.Algorithm) == UnknownPublicKeyAlgorithm {
return nil, fmt.Errorf("x509: unsupported public key type: %T", pub)
}
asn1Issuer, err := subjectBytes(parent)
if err != nil {
return nil, err
}
asn1Subject, err := subjectBytes(template)
if err != nil {
return nil, err
}
authorityKeyId := template.AuthorityKeyId
if !bytes.Equal(asn1Issuer, asn1Subject) && len(parent.SubjectKeyId) > 0 {
authorityKeyId = parent.SubjectKeyId
}
subjectKeyId := template.SubjectKeyId
if len(subjectKeyId) == 0 && template.IsCA {
// SubjectKeyId generated using method 1 in RFC 5280, Section 4.2.1.2:
// (1) The keyIdentifier is composed of the 160-bit SHA-1 hash of the
// value of the BIT STRING subjectPublicKey (excluding the tag,
// length, and number of unused bits).
h := sha1.Sum(publicKeyBytes)
subjectKeyId = h[:]
}
// Check that the signer's public key matches the private key, if available.
type privateKey interface {
Equal(crypto.PublicKey) bool
}
if privPub, ok := key.Public().(privateKey); !ok {
return nil, errors.New("x509: internal error: supported public key does not implement Equal")
} else if parent.PublicKey != nil && !privPub.Equal(parent.PublicKey) {
return nil, errors.New("x509: provided PrivateKey doesn't match parent's PublicKey")
}
extensions, err := buildCertExtensions(template, bytes.Equal(asn1Subject, emptyASN1Subject), authorityKeyId, subjectKeyId)
if err != nil {
return nil, err
}
encodedPublicKey := asn1.BitString{BitLength: len(publicKeyBytes) * 8, Bytes: publicKeyBytes}
c := tbsCertificate{
Version: 2,
SerialNumber: serialNumber,
SignatureAlgorithm: algorithmIdentifier,
Issuer: asn1.RawValue{FullBytes: asn1Issuer},
Validity: validity{template.NotBefore.UTC(), template.NotAfter.UTC()},
Subject: asn1.RawValue{FullBytes: asn1Subject},
PublicKey: publicKeyInfo{nil, publicKeyAlgorithm, encodedPublicKey},
Extensions: extensions,
}
tbsCertContents, err := asn1.Marshal(c)
if err != nil {
return nil, err
}
c.Raw = tbsCertContents
signature, err := signTBS(tbsCertContents, key, signatureAlgorithm, rand)
if err != nil {
return nil, err
}
return asn1.Marshal(certificate{
TBSCertificate: c,
SignatureAlgorithm: algorithmIdentifier,
SignatureValue: asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
})
}
// pemCRLPrefix is the magic string that indicates that we have a PEM encoded
// CRL.
var pemCRLPrefix = []byte("-----BEGIN X509 CRL")
// pemType is the type of a PEM encoded CRL.
var pemType = "X509 CRL"
// ParseCRL parses a CRL from the given bytes. It's often the case that PEM
// encoded CRLs will appear where they should be DER encoded, so this function
// will transparently handle PEM encoding as long as there isn't any leading
// garbage.
//
// Deprecated: Use [ParseRevocationList] instead.
func ParseCRL(crlBytes []byte) (*pkix.CertificateList, error) {
if bytes.HasPrefix(crlBytes, pemCRLPrefix) {
block, _ := pem.Decode(crlBytes)
if block != nil && block.Type == pemType {
crlBytes = block.Bytes
}
}
return ParseDERCRL(crlBytes)
}
// ParseDERCRL parses a DER encoded CRL from the given bytes.
//
// Deprecated: Use [ParseRevocationList] instead.
func ParseDERCRL(derBytes []byte) (*pkix.CertificateList, error) {
certList := new(pkix.CertificateList)
if rest, err := asn1.Unmarshal(derBytes, certList); err != nil {
return nil, err
} else if len(rest) != 0 {
return nil, errors.New("x509: trailing data after CRL")
}
return certList, nil
}
// CreateCRL returns a DER encoded CRL, signed by this Certificate, that
// contains the given list of revoked certificates.
//
// Deprecated: this method does not generate an RFC 5280 conformant X.509 v2 CRL.
// To generate a standards compliant CRL, use [CreateRevocationList] instead.
func (c *Certificate) CreateCRL(rand io.Reader, priv any, revokedCerts []pkix.RevokedCertificate, now, expiry time.Time) (crlBytes []byte, err error) {
key, ok := priv.(crypto.Signer)
if !ok {
return nil, errors.New("x509: certificate private key does not implement crypto.Signer")
}
signatureAlgorithm, algorithmIdentifier, err := signingParamsForKey(key, 0)
if err != nil {
return nil, err
}
// Force revocation times to UTC per RFC 5280.
revokedCertsUTC := make([]pkix.RevokedCertificate, len(revokedCerts))
for i, rc := range revokedCerts {
rc.RevocationTime = rc.RevocationTime.UTC()
revokedCertsUTC[i] = rc
}
tbsCertList := pkix.TBSCertificateList{
Version: 1,
Signature: algorithmIdentifier,
Issuer: c.Subject.ToRDNSequence(),
ThisUpdate: now.UTC(),
NextUpdate: expiry.UTC(),
RevokedCertificates: revokedCertsUTC,
}
// Authority Key Id
if len(c.SubjectKeyId) > 0 {
var aki pkix.Extension
aki.Id = oidExtensionAuthorityKeyId
aki.Value, err = asn1.Marshal(authKeyId{Id: c.SubjectKeyId})
if err != nil {
return nil, err
}
tbsCertList.Extensions = append(tbsCertList.Extensions, aki)
}
tbsCertListContents, err := asn1.Marshal(tbsCertList)
if err != nil {
return nil, err
}
tbsCertList.Raw = tbsCertListContents
signature, err := signTBS(tbsCertListContents, key, signatureAlgorithm, rand)
if err != nil {
return nil, err
}
return asn1.Marshal(pkix.CertificateList{
TBSCertList: tbsCertList,
SignatureAlgorithm: algorithmIdentifier,
SignatureValue: asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
})
}
// CertificateRequest represents a PKCS #10, certificate signature request.
type CertificateRequest struct {
Raw []byte // Complete ASN.1 DER content (CSR, signature algorithm and signature).
RawTBSCertificateRequest []byte // Certificate request info part of raw ASN.1 DER content.
RawSubjectPublicKeyInfo []byte // DER encoded SubjectPublicKeyInfo.
RawSubject []byte // DER encoded Subject.
Version int
Signature []byte
SignatureAlgorithm SignatureAlgorithm
PublicKeyAlgorithm PublicKeyAlgorithm
PublicKey any
Subject pkix.Name
// Attributes contains the CSR attributes that can parse as
// pkix.AttributeTypeAndValueSET.
//
// Deprecated: Use Extensions and ExtraExtensions instead for parsing and
// generating the requestedExtensions attribute.
Attributes []pkix.AttributeTypeAndValueSET
// Extensions contains all requested extensions, in raw form. When parsing
// CSRs, this can be used to extract extensions that are not parsed by this
// package.
Extensions []pkix.Extension
// ExtraExtensions contains extensions to be copied, raw, into any CSR
// marshaled by CreateCertificateRequest. Values override any extensions
// that would otherwise be produced based on the other fields but are
// overridden by any extensions specified in Attributes.
//
// The ExtraExtensions field is not populated by ParseCertificateRequest,
// see Extensions instead.
ExtraExtensions []pkix.Extension
// Subject Alternate Name values.
DNSNames []string
EmailAddresses []string
IPAddresses []net.IP
URIs []*url.URL
}
// These structures reflect the ASN.1 structure of X.509 certificate
// signature requests (see RFC 2986):
type tbsCertificateRequest struct {
Raw asn1.RawContent
Version int
Subject asn1.RawValue
PublicKey publicKeyInfo
RawAttributes []asn1.RawValue `asn1:"tag:0"`
}
type certificateRequest struct {
Raw asn1.RawContent
TBSCSR tbsCertificateRequest
SignatureAlgorithm pkix.AlgorithmIdentifier
SignatureValue asn1.BitString
}
// oidExtensionRequest is a PKCS #9 OBJECT IDENTIFIER that indicates requested
// extensions in a CSR.
var oidExtensionRequest = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 14}
// newRawAttributes converts AttributeTypeAndValueSETs from a template
// CertificateRequest's Attributes into tbsCertificateRequest RawAttributes.
func newRawAttributes(attributes []pkix.AttributeTypeAndValueSET) ([]asn1.RawValue, error) {
var rawAttributes []asn1.RawValue
b, err := asn1.Marshal(attributes)
if err != nil {
return nil, err
}
rest, err := asn1.Unmarshal(b, &rawAttributes)
if err != nil {
return nil, err
}
if len(rest) != 0 {
return nil, errors.New("x509: failed to unmarshal raw CSR Attributes")
}
return rawAttributes, nil
}
// parseRawAttributes Unmarshals RawAttributes into AttributeTypeAndValueSETs.
func parseRawAttributes(rawAttributes []asn1.RawValue) []pkix.AttributeTypeAndValueSET {
var attributes []pkix.AttributeTypeAndValueSET
for _, rawAttr := range rawAttributes {
var attr pkix.AttributeTypeAndValueSET
rest, err := asn1.Unmarshal(rawAttr.FullBytes, &attr)
// Ignore attributes that don't parse into pkix.AttributeTypeAndValueSET
// (i.e.: challengePassword or unstructuredName).
if err == nil && len(rest) == 0 {
attributes = append(attributes, attr)
}
}
return attributes
}
// parseCSRExtensions parses the attributes from a CSR and extracts any
// requested extensions.
func parseCSRExtensions(rawAttributes []asn1.RawValue) ([]pkix.Extension, error) {
// pkcs10Attribute reflects the Attribute structure from RFC 2986, Section 4.1.
type pkcs10Attribute struct {
Id asn1.ObjectIdentifier
Values []asn1.RawValue `asn1:"set"`
}
var ret []pkix.Extension
requestedExts := make(map[string]bool)
for _, rawAttr := range rawAttributes {
var attr pkcs10Attribute
if rest, err := asn1.Unmarshal(rawAttr.FullBytes, &attr); err != nil || len(rest) != 0 || len(attr.Values) == 0 {
// Ignore attributes that don't parse.
continue
}
if !attr.Id.Equal(oidExtensionRequest) {
continue
}
var extensions []pkix.Extension
if _, err := asn1.Unmarshal(attr.Values[0].FullBytes, &extensions); err != nil {
return nil, err
}
for _, ext := range extensions {
oidStr := ext.Id.String()
if requestedExts[oidStr] {
return nil, errors.New("x509: certificate request contains duplicate requested extensions")
}
requestedExts[oidStr] = true
}
ret = append(ret, extensions...)
}
return ret, nil
}
// CreateCertificateRequest creates a new certificate request based on a
// template. The following members of template are used:
//
// - SignatureAlgorithm
// - Subject
// - DNSNames
// - EmailAddresses
// - IPAddresses
// - URIs
// - ExtraExtensions
// - Attributes (deprecated)
//
// priv is the private key to sign the CSR with, and the corresponding public
// key will be included in the CSR. It must implement crypto.Signer and its
// Public() method must return a *rsa.PublicKey or a *ecdsa.PublicKey or a
// ed25519.PublicKey. (A *rsa.PrivateKey, *ecdsa.PrivateKey or
// ed25519.PrivateKey satisfies this.)
//
// The returned slice is the certificate request in DER encoding.
func CreateCertificateRequest(rand io.Reader, template *CertificateRequest, priv any) (csr []byte, err error) {
key, ok := priv.(crypto.Signer)
if !ok {
return nil, errors.New("x509: certificate private key does not implement crypto.Signer")
}
signatureAlgorithm, algorithmIdentifier, err := signingParamsForKey(key, template.SignatureAlgorithm)
if err != nil {
return nil, err
}
var publicKeyBytes []byte
var publicKeyAlgorithm pkix.AlgorithmIdentifier
publicKeyBytes, publicKeyAlgorithm, err = marshalPublicKey(key.Public())
if err != nil {
return nil, err
}
extensions, err := buildCSRExtensions(template)
if err != nil {
return nil, err
}
// Make a copy of template.Attributes because we may alter it below.
attributes := make([]pkix.AttributeTypeAndValueSET, 0, len(template.Attributes))
for _, attr := range template.Attributes {
values := make([][]pkix.AttributeTypeAndValue, len(attr.Value))
copy(values, attr.Value)
attributes = append(attributes, pkix.AttributeTypeAndValueSET{
Type: attr.Type,
Value: values,
})
}
extensionsAppended := false
if len(extensions) > 0 {
// Append the extensions to an existing attribute if possible.
for _, atvSet := range attributes {
if !atvSet.Type.Equal(oidExtensionRequest) || len(atvSet.Value) == 0 {
continue
}
// specifiedExtensions contains all the extensions that we
// found specified via template.Attributes.
specifiedExtensions := make(map[string]bool)
for _, atvs := range atvSet.Value {
for _, atv := range atvs {
specifiedExtensions[atv.Type.String()] = true
}
}
newValue := make([]pkix.AttributeTypeAndValue, 0, len(atvSet.Value[0])+len(extensions))
newValue = append(newValue, atvSet.Value[0]...)
for _, e := range extensions {
if specifiedExtensions[e.Id.String()] {
// Attributes already contained a value for
// this extension and it takes priority.
continue
}
newValue = append(newValue, pkix.AttributeTypeAndValue{
// There is no place for the critical
// flag in an AttributeTypeAndValue.
Type: e.Id,
Value: e.Value,
})
}
atvSet.Value[0] = newValue
extensionsAppended = true
break
}
}
rawAttributes, err := newRawAttributes(attributes)
if err != nil {
return nil, err
}
// If not included in attributes, add a new attribute for the
// extensions.
if len(extensions) > 0 && !extensionsAppended {
attr := struct {
Type asn1.ObjectIdentifier
Value [][]pkix.Extension `asn1:"set"`
}{
Type: oidExtensionRequest,
Value: [][]pkix.Extension{extensions},
}
b, err := asn1.Marshal(attr)
if err != nil {
return nil, errors.New("x509: failed to serialise extensions attribute: " + err.Error())
}
var rawValue asn1.RawValue
if _, err := asn1.Unmarshal(b, &rawValue); err != nil {
return nil, err
}
rawAttributes = append(rawAttributes, rawValue)
}
asn1Subject := template.RawSubject
if len(asn1Subject) == 0 {
asn1Subject, err = asn1.Marshal(template.Subject.ToRDNSequence())
if err != nil {
return nil, err
}
}
tbsCSR := tbsCertificateRequest{
Version: 0, // PKCS #10, RFC 2986
Subject: asn1.RawValue{FullBytes: asn1Subject},
PublicKey: publicKeyInfo{
Algorithm: publicKeyAlgorithm,
PublicKey: asn1.BitString{
Bytes: publicKeyBytes,
BitLength: len(publicKeyBytes) * 8,
},
},
RawAttributes: rawAttributes,
}
tbsCSRContents, err := asn1.Marshal(tbsCSR)
if err != nil {
return nil, err
}
tbsCSR.Raw = tbsCSRContents
signature, err := signTBS(tbsCSRContents, key, signatureAlgorithm, rand)
if err != nil {
return nil, err
}
return asn1.Marshal(certificateRequest{
TBSCSR: tbsCSR,
SignatureAlgorithm: algorithmIdentifier,
SignatureValue: asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
})
}
// ParseCertificateRequest parses a single certificate request from the
// given ASN.1 DER data.
func ParseCertificateRequest(asn1Data []byte) (*CertificateRequest, error) {
var csr certificateRequest
rest, err := asn1.Unmarshal(asn1Data, &csr)
if err != nil {
return nil, err
} else if len(rest) != 0 {
return nil, asn1.SyntaxError{Msg: "trailing data"}
}
return parseCertificateRequest(&csr)
}
func parseCertificateRequest(in *certificateRequest) (*CertificateRequest, error) {
out := &CertificateRequest{
Raw: in.Raw,
RawTBSCertificateRequest: in.TBSCSR.Raw,
RawSubjectPublicKeyInfo: in.TBSCSR.PublicKey.Raw,
RawSubject: in.TBSCSR.Subject.FullBytes,
Signature: in.SignatureValue.RightAlign(),
SignatureAlgorithm: getSignatureAlgorithmFromAI(in.SignatureAlgorithm),
PublicKeyAlgorithm: getPublicKeyAlgorithmFromOID(in.TBSCSR.PublicKey.Algorithm.Algorithm),
Version: in.TBSCSR.Version,
Attributes: parseRawAttributes(in.TBSCSR.RawAttributes),
}
var err error
if out.PublicKeyAlgorithm != UnknownPublicKeyAlgorithm {
out.PublicKey, err = parsePublicKey(&in.TBSCSR.PublicKey)
if err != nil {
return nil, err
}
}
var subject pkix.RDNSequence
if rest, err := asn1.Unmarshal(in.TBSCSR.Subject.FullBytes, &subject); err != nil {
return nil, err
} else if len(rest) != 0 {
return nil, errors.New("x509: trailing data after X.509 Subject")
}
out.Subject.FillFromRDNSequence(&subject)
if out.Extensions, err = parseCSRExtensions(in.TBSCSR.RawAttributes); err != nil {
return nil, err
}
for _, extension := range out.Extensions {
switch {
case extension.Id.Equal(oidExtensionSubjectAltName):
out.DNSNames, out.EmailAddresses, out.IPAddresses, out.URIs, err = parseSANExtension(extension.Value)
if err != nil {
return nil, err
}
}
}
return out, nil
}
// CheckSignature reports whether the signature on c is valid.
func (c *CertificateRequest) CheckSignature() error {
return checkSignature(c.SignatureAlgorithm, c.RawTBSCertificateRequest, c.Signature, c.PublicKey, true)
}
// RevocationListEntry represents an entry in the revokedCertificates
// sequence of a CRL.
type RevocationListEntry struct {
// Raw contains the raw bytes of the revokedCertificates entry. It is set when
// parsing a CRL; it is ignored when generating a CRL.
Raw []byte
// SerialNumber represents the serial number of a revoked certificate. It is
// both used when creating a CRL and populated when parsing a CRL. It must not
// be nil.
SerialNumber *big.Int
// RevocationTime represents the time at which the certificate was revoked. It
// is both used when creating a CRL and populated when parsing a CRL. It must
// not be the zero time.
RevocationTime time.Time
// ReasonCode represents the reason for revocation, using the integer enum
// values specified in RFC 5280 Section 5.3.1. When creating a CRL, the zero
// value will result in the reasonCode extension being omitted. When parsing a
// CRL, the zero value may represent either the reasonCode extension being
// absent (which implies the default revocation reason of 0/Unspecified), or
// it may represent the reasonCode extension being present and explicitly
// containing a value of 0/Unspecified (which should not happen according to
// the DER encoding rules, but can and does happen anyway).
ReasonCode int
// Extensions contains raw X.509 extensions. When parsing CRL entries,
// this can be used to extract non-critical extensions that are not
// parsed by this package. When marshaling CRL entries, the Extensions
// field is ignored, see ExtraExtensions.
Extensions []pkix.Extension
// ExtraExtensions contains extensions to be copied, raw, into any
// marshaled CRL entries. Values override any extensions that would
// otherwise be produced based on the other fields. The ExtraExtensions
// field is not populated when parsing CRL entries, see Extensions.
ExtraExtensions []pkix.Extension
}
// RevocationList represents a [Certificate] Revocation List (CRL) as specified
// by RFC 5280.
type RevocationList struct {
// Raw contains the complete ASN.1 DER content of the CRL (tbsCertList,
// signatureAlgorithm, and signatureValue.)
Raw []byte
// RawTBSRevocationList contains just the tbsCertList portion of the ASN.1
// DER.
RawTBSRevocationList []byte
// RawIssuer contains the DER encoded Issuer.
RawIssuer []byte
// Issuer contains the DN of the issuing certificate.
Issuer pkix.Name
// AuthorityKeyId is used to identify the public key associated with the
// issuing certificate. It is populated from the authorityKeyIdentifier
// extension when parsing a CRL. It is ignored when creating a CRL; the
// extension is populated from the issuing certificate itself.
AuthorityKeyId []byte
Signature []byte
// SignatureAlgorithm is used to determine the signature algorithm to be
// used when signing the CRL. If 0 the default algorithm for the signing
// key will be used.
SignatureAlgorithm SignatureAlgorithm
// RevokedCertificateEntries represents the revokedCertificates sequence in
// the CRL. It is used when creating a CRL and also populated when parsing a
// CRL. When creating a CRL, it may be empty or nil, in which case the
// revokedCertificates ASN.1 sequence will be omitted from the CRL entirely.
RevokedCertificateEntries []RevocationListEntry
// RevokedCertificates is used to populate the revokedCertificates
// sequence in the CRL if RevokedCertificateEntries is empty. It may be empty
// or nil, in which case an empty CRL will be created.
//
// Deprecated: Use RevokedCertificateEntries instead.
RevokedCertificates []pkix.RevokedCertificate
// Number is used to populate the X.509 v2 cRLNumber extension in the CRL,
// which should be a monotonically increasing sequence number for a given
// CRL scope and CRL issuer. It is also populated from the cRLNumber
// extension when parsing a CRL.
Number *big.Int
// ThisUpdate is used to populate the thisUpdate field in the CRL, which
// indicates the issuance date of the CRL.
ThisUpdate time.Time
// NextUpdate is used to populate the nextUpdate field in the CRL, which
// indicates the date by which the next CRL will be issued. NextUpdate
// must be greater than ThisUpdate.
NextUpdate time.Time
// Extensions contains raw X.509 extensions. When creating a CRL,
// the Extensions field is ignored, see ExtraExtensions.
Extensions []pkix.Extension
// ExtraExtensions contains any additional extensions to add directly to
// the CRL.
ExtraExtensions []pkix.Extension
}
// These structures reflect the ASN.1 structure of X.509 CRLs better than
// the existing crypto/x509/pkix variants do. These mirror the existing
// certificate structs in this file.
//
// Notably, we include issuer as an asn1.RawValue, mirroring the behavior of
// tbsCertificate and allowing raw (unparsed) subjects to be passed cleanly.
type certificateList struct {
TBSCertList tbsCertificateList
SignatureAlgorithm pkix.AlgorithmIdentifier
SignatureValue asn1.BitString
}
type tbsCertificateList struct {
Raw asn1.RawContent
Version int `asn1:"optional,default:0"`
Signature pkix.AlgorithmIdentifier
Issuer asn1.RawValue
ThisUpdate time.Time
NextUpdate time.Time `asn1:"optional"`
RevokedCertificates []pkix.RevokedCertificate `asn1:"optional"`
Extensions []pkix.Extension `asn1:"tag:0,optional,explicit"`
}
// CreateRevocationList creates a new X.509 v2 [Certificate] Revocation List,
// according to RFC 5280, based on template.
//
// The CRL is signed by priv which should be the private key associated with
// the public key in the issuer certificate.
//
// The issuer may not be nil, and the crlSign bit must be set in [KeyUsage] in
// order to use it as a CRL issuer.
//
// The issuer distinguished name CRL field and authority key identifier
// extension are populated using the issuer certificate. issuer must have
// SubjectKeyId set.
func CreateRevocationList(rand io.Reader, template *RevocationList, issuer *Certificate, priv crypto.Signer) ([]byte, error) {
if template == nil {
return nil, errors.New("x509: template can not be nil")
}
if issuer == nil {
return nil, errors.New("x509: issuer can not be nil")
}
if (issuer.KeyUsage & KeyUsageCRLSign) == 0 {
return nil, errors.New("x509: issuer must have the crlSign key usage bit set")
}
if len(issuer.SubjectKeyId) == 0 {
return nil, errors.New("x509: issuer certificate doesn't contain a subject key identifier")
}
if template.NextUpdate.Before(template.ThisUpdate) {
return nil, errors.New("x509: template.ThisUpdate is after template.NextUpdate")
}
if template.Number == nil {
return nil, errors.New("x509: template contains nil Number field")
}
signatureAlgorithm, algorithmIdentifier, err := signingParamsForKey(priv, template.SignatureAlgorithm)
if err != nil {
return nil, err
}
var revokedCerts []pkix.RevokedCertificate
// Only process the deprecated RevokedCertificates field if it is populated
// and the new RevokedCertificateEntries field is not populated.
if len(template.RevokedCertificates) > 0 && len(template.RevokedCertificateEntries) == 0 {
// Force revocation times to UTC per RFC 5280.
revokedCerts = make([]pkix.RevokedCertificate, len(template.RevokedCertificates))
for i, rc := range template.RevokedCertificates {
rc.RevocationTime = rc.RevocationTime.UTC()
revokedCerts[i] = rc
}
} else {
// Convert the ReasonCode field to a proper extension, and force revocation
// times to UTC per RFC 5280.
revokedCerts = make([]pkix.RevokedCertificate, len(template.RevokedCertificateEntries))
for i, rce := range template.RevokedCertificateEntries {
if rce.SerialNumber == nil {
return nil, errors.New("x509: template contains entry with nil SerialNumber field")
}
if rce.RevocationTime.IsZero() {
return nil, errors.New("x509: template contains entry with zero RevocationTime field")
}
rc := pkix.RevokedCertificate{
SerialNumber: rce.SerialNumber,
RevocationTime: rce.RevocationTime.UTC(),
}
// Copy over any extra extensions, except for a Reason Code extension,
// because we'll synthesize that ourselves to ensure it is correct.
exts := make([]pkix.Extension, 0, len(rce.ExtraExtensions))
for _, ext := range rce.ExtraExtensions {
if ext.Id.Equal(oidExtensionReasonCode) {
return nil, errors.New("x509: template contains entry with ReasonCode ExtraExtension; use ReasonCode field instead")
}
exts = append(exts, ext)
}
// Only add a reasonCode extension if the reason is non-zero, as per
// RFC 5280 Section 5.3.1.
if rce.ReasonCode != 0 {
reasonBytes, err := asn1.Marshal(asn1.Enumerated(rce.ReasonCode))
if err != nil {
return nil, err
}
exts = append(exts, pkix.Extension{
Id: oidExtensionReasonCode,
Value: reasonBytes,
})
}
if len(exts) > 0 {
rc.Extensions = exts
}
revokedCerts[i] = rc
}
}
aki, err := asn1.Marshal(authKeyId{Id: issuer.SubjectKeyId})
if err != nil {
return nil, err
}
if numBytes := template.Number.Bytes(); len(numBytes) > 20 || (len(numBytes) == 20 && numBytes[0]&0x80 != 0) {
return nil, errors.New("x509: CRL number exceeds 20 octets")
}
crlNum, err := asn1.Marshal(template.Number)
if err != nil {
return nil, err
}
// Correctly use the issuer's subject sequence if one is specified.
issuerSubject, err := subjectBytes(issuer)
if err != nil {
return nil, err
}
tbsCertList := tbsCertificateList{
Version: 1, // v2
Signature: algorithmIdentifier,
Issuer: asn1.RawValue{FullBytes: issuerSubject},
ThisUpdate: template.ThisUpdate.UTC(),
NextUpdate: template.NextUpdate.UTC(),
Extensions: []pkix.Extension{
{
Id: oidExtensionAuthorityKeyId,
Value: aki,
},
{
Id: oidExtensionCRLNumber,
Value: crlNum,
},
},
}
if len(revokedCerts) > 0 {
tbsCertList.RevokedCertificates = revokedCerts
}
if len(template.ExtraExtensions) > 0 {
tbsCertList.Extensions = append(tbsCertList.Extensions, template.ExtraExtensions...)
}
tbsCertListContents, err := asn1.Marshal(tbsCertList)
if err != nil {
return nil, err
}
// Optimization to only marshal this struct once, when signing and
// then embedding in certificateList below.
tbsCertList.Raw = tbsCertListContents
signature, err := signTBS(tbsCertListContents, priv, signatureAlgorithm, rand)
if err != nil {
return nil, err
}
return asn1.Marshal(certificateList{
TBSCertList: tbsCertList,
SignatureAlgorithm: algorithmIdentifier,
SignatureValue: asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
})
}
// CheckSignatureFrom verifies that the signature on rl is a valid signature
// from issuer.
func (rl *RevocationList) CheckSignatureFrom(parent *Certificate) error {
if parent.Version == 3 && !parent.BasicConstraintsValid ||
parent.BasicConstraintsValid && !parent.IsCA {
return ConstraintViolationError{}
}
if parent.KeyUsage != 0 && parent.KeyUsage&KeyUsageCRLSign == 0 {
return ConstraintViolationError{}
}
if parent.PublicKeyAlgorithm == UnknownPublicKeyAlgorithm {
return ErrUnsupportedAlgorithm
}
return parent.CheckSignature(rl.SignatureAlgorithm, rl.RawTBSRevocationList, rl.Signature)
}