1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // Package x509 implements a subset of the X.509 standard.
7 // It allows parsing and generating certificates, certificate signing
8 // requests, certificate revocation lists, and encoded public and private keys.
9 // It provides a certificate verifier, complete with a chain builder.
11 // The package targets the X.509 technical profile defined by the IETF (RFC
12 // 2459/3280/5280), and as further restricted by the CA/Browser Forum Baseline
13 // Requirements. There is minimal support for features outside of these
14 // profiles, as the primary goal of the package is to provide compatibility
15 // with the publicly trusted TLS certificate ecosystem and its policies and
18 // On macOS and Windows, certificate verification is handled by system APIs, but
19 // the package aims to apply consistent validation rules across operating
46 // Explicitly import these for their crypto.RegisterHash init side-effects.
47 // Keep these as blank imports, even if they're imported above.
52 "crypto/go.cypherpunks.ru/gogost/v5/gost3410"
53 "golang.org/x/crypto/cryptobyte"
54 cryptobyte_asn1 "golang.org/x/crypto/cryptobyte/asn1"
57 // pkixPublicKey reflects a PKIX public key structure. See SubjectPublicKeyInfo
59 type pkixPublicKey struct {
60 Algo pkix.AlgorithmIdentifier
61 BitString asn1.BitString
64 // ParsePKIXPublicKey parses a public key in PKIX, ASN.1 DER form. The encoded
65 // public key is a SubjectPublicKeyInfo structure (see RFC 5280, Section 4.1).
67 // It returns a *rsa.PublicKey, *dsa.PublicKey, *ecdsa.PublicKey,
68 // ed25519.PublicKey (not a pointer), or *ecdh.PublicKey (for X25519).
69 // More types might be supported in the future.
71 // This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".
72 func ParsePKIXPublicKey(derBytes []byte) (pub any, err error) {
74 if rest, err := asn1.Unmarshal(derBytes, &pki); err != nil {
75 if _, err := asn1.Unmarshal(derBytes, &pkcs1PublicKey{}); err == nil {
76 return nil, errors.New("x509: failed to parse public key (use ParsePKCS1PublicKey instead for this key format)")
79 } else if len(rest) != 0 {
80 return nil, errors.New("x509: trailing data after ASN.1 of public-key")
82 return parsePublicKey(&pki)
85 func marshalPublicKey(pub any) (publicKeyBytes []byte, publicKeyAlgorithm pkix.AlgorithmIdentifier, err error) {
86 switch pub := pub.(type) {
88 publicKeyBytes, err = asn1.Marshal(pkcs1PublicKey{
93 return nil, pkix.AlgorithmIdentifier{}, err
95 publicKeyAlgorithm.Algorithm = oidPublicKeyRSA
96 // This is a NULL parameters value which is required by
97 // RFC 3279, Section 2.3.1.
98 publicKeyAlgorithm.Parameters = asn1.NullRawValue
99 case *ecdsa.PublicKey:
100 oid, ok := oidFromNamedCurve(pub.Curve)
102 return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")
104 if !pub.Curve.IsOnCurve(pub.X, pub.Y) {
105 return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: invalid elliptic curve public key")
107 publicKeyBytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)
108 publicKeyAlgorithm.Algorithm = oidPublicKeyECDSA
109 var paramBytes []byte
110 paramBytes, err = asn1.Marshal(oid)
114 publicKeyAlgorithm.Parameters.FullBytes = paramBytes
115 case ed25519.PublicKey:
117 publicKeyAlgorithm.Algorithm = oidPublicKeyEd25519
118 case *ecdh.PublicKey:
119 publicKeyBytes = pub.Bytes()
120 if pub.Curve() == ecdh.X25519() {
121 publicKeyAlgorithm.Algorithm = oidPublicKeyX25519
123 oid, ok := oidFromECDHCurve(pub.Curve())
125 return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported elliptic curve")
127 publicKeyAlgorithm.Algorithm = oidPublicKeyECDSA
128 var paramBytes []byte
129 paramBytes, err = asn1.Marshal(oid)
133 publicKeyAlgorithm.Parameters.FullBytes = paramBytes
135 case *gost3410.PublicKey:
136 builder := cryptobyte.NewBuilder(nil)
137 builder.AddASN1OctetString(pub.Raw())
138 publicKeyBytes, err = builder.Bytes()
142 params := GostR341012PublicKeyParameters{}
144 case "id-GostR3410-2001-CryptoPro-A-ParamSet":
145 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
146 params.PublicKeyParamSet = oidGostR34102001CryptoProAParamSet
147 params.DigestParamSet = oidTc26Gost34112012256
148 case "id-GostR3410-2001-CryptoPro-B-ParamSet":
149 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
150 params.PublicKeyParamSet = oidGostR34102001CryptoProBParamSet
151 params.DigestParamSet = oidTc26Gost34112012256
152 case "id-GostR3410-2001-CryptoPro-C-ParamSet":
153 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
154 params.PublicKeyParamSet = oidGostR34102001CryptoProCParamSet
155 params.DigestParamSet = oidTc26Gost34112012256
156 case "id-GostR3410-2001-CryptoPro-XchA-ParamSet":
157 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
158 params.PublicKeyParamSet = oidGostR34102001CryptoProXchAParamSet
159 params.DigestParamSet = oidTc26Gost34112012256
160 case "id-GostR3410-2001-CryptoPro-XchB-ParamSet":
161 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
162 params.PublicKeyParamSet = oidGostR34102001CryptoProXchBParamSet
163 params.DigestParamSet = oidTc26Gost34112012256
164 case "id-tc26-gost-3410-12-256-paramSetA":
165 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
166 params.PublicKeyParamSet = oidTc26Gost341012256ParamSetA
167 case "id-tc26-gost-3410-12-256-paramSetB":
168 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
169 params.PublicKeyParamSet = oidTc26Gost341012256ParamSetB
170 case "id-tc26-gost-3410-12-256-paramSetC":
171 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
172 params.PublicKeyParamSet = oidTc26Gost341012256ParamSetC
173 case "id-tc26-gost-3410-12-256-paramSetD":
174 publicKeyAlgorithm.Algorithm = oidTc26Gost341012256
175 params.PublicKeyParamSet = oidTc26Gost341012256ParamSetD
176 case "id-tc26-gost-3410-12-512-paramSetA":
177 publicKeyAlgorithm.Algorithm = oidTc26Gost341012512
178 params.PublicKeyParamSet = oidTc26Gost341012512ParamSetA
179 case "id-tc26-gost-3410-12-512-paramSetB":
180 publicKeyAlgorithm.Algorithm = oidTc26Gost341012512
181 params.PublicKeyParamSet = oidTc26Gost341012512ParamSetB
182 case "id-tc26-gost-3410-12-512-paramSetC":
183 publicKeyAlgorithm.Algorithm = oidTc26Gost341012512
184 params.PublicKeyParamSet = oidTc26Gost341012512ParamSetC
186 return nil, pkix.AlgorithmIdentifier{}, errors.New("x509: unsupported GOST elliptic curve")
188 publicKeyAlgorithm.Parameters.FullBytes, err = asn1.Marshal(params)
193 return nil, pkix.AlgorithmIdentifier{}, fmt.Errorf("x509: unsupported public key type: %T", pub)
196 return publicKeyBytes, publicKeyAlgorithm, nil
199 // MarshalPKIXPublicKey converts a public key to PKIX, ASN.1 DER form.
200 // The encoded public key is a SubjectPublicKeyInfo structure
201 // (see RFC 5280, Section 4.1).
203 // The following key types are currently supported: *rsa.PublicKey,
204 // *ecdsa.PublicKey, ed25519.PublicKey (not a pointer), and *ecdh.PublicKey.
205 // Unsupported key types result in an error.
207 // This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".
208 func MarshalPKIXPublicKey(pub any) ([]byte, error) {
209 var publicKeyBytes []byte
210 var publicKeyAlgorithm pkix.AlgorithmIdentifier
213 if publicKeyBytes, publicKeyAlgorithm, err = marshalPublicKey(pub); err != nil {
217 pkix := pkixPublicKey{
218 Algo: publicKeyAlgorithm,
219 BitString: asn1.BitString{
220 Bytes: publicKeyBytes,
221 BitLength: 8 * len(publicKeyBytes),
225 ret, _ := asn1.Marshal(pkix)
229 // These structures reflect the ASN.1 structure of X.509 certificates.:
231 type certificate struct {
232 TBSCertificate tbsCertificate
233 SignatureAlgorithm pkix.AlgorithmIdentifier
234 SignatureValue asn1.BitString
237 type tbsCertificate struct {
239 Version int `asn1:"optional,explicit,default:0,tag:0"`
240 SerialNumber *big.Int
241 SignatureAlgorithm pkix.AlgorithmIdentifier
244 Subject asn1.RawValue
245 PublicKey publicKeyInfo
246 UniqueId asn1.BitString `asn1:"optional,tag:1"`
247 SubjectUniqueId asn1.BitString `asn1:"optional,tag:2"`
248 Extensions []pkix.Extension `asn1:"omitempty,optional,explicit,tag:3"`
251 type dsaAlgorithmParameters struct {
255 type validity struct {
256 NotBefore, NotAfter time.Time
259 type publicKeyInfo struct {
261 Algorithm pkix.AlgorithmIdentifier
262 PublicKey asn1.BitString
266 type authKeyId struct {
267 Id []byte `asn1:"optional,tag:0"`
270 type SignatureAlgorithm int
273 UnknownSignatureAlgorithm SignatureAlgorithm = iota
275 MD2WithRSA // Unsupported.
276 MD5WithRSA // Only supported for signing, not verification.
277 SHA1WithRSA // Only supported for signing, and verification of CRLs, CSRs, and OCSP responses.
281 DSAWithSHA1 // Unsupported.
282 DSAWithSHA256 // Unsupported.
283 ECDSAWithSHA1 // Only supported for signing, and verification of CRLs, CSRs, and OCSP responses.
295 func (algo SignatureAlgorithm) isRSAPSS() bool {
297 case SHA256WithRSAPSS, SHA384WithRSAPSS, SHA512WithRSAPSS:
304 func (algo SignatureAlgorithm) String() string {
305 for _, details := range signatureAlgorithmDetails {
306 if details.algo == algo {
310 return strconv.Itoa(int(algo))
313 type PublicKeyAlgorithm int
316 UnknownPublicKeyAlgorithm PublicKeyAlgorithm = iota
318 DSA // Only supported for parsing.
324 var publicKeyAlgoName = [...]string{
332 func (algo PublicKeyAlgorithm) String() string {
333 if 0 < algo && int(algo) < len(publicKeyAlgoName) {
334 return publicKeyAlgoName[algo]
336 return strconv.Itoa(int(algo))
339 // OIDs for signature algorithms
341 // pkcs-1 OBJECT IDENTIFIER ::= {
342 // iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 1 }
344 // RFC 3279 2.2.1 RSA Signature Algorithms
346 // md2WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 2 }
348 // md5WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 4 }
350 // sha-1WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 5 }
352 // dsaWithSha1 OBJECT IDENTIFIER ::= {
353 // iso(1) member-body(2) us(840) x9-57(10040) x9cm(4) 3 }
355 // RFC 3279 2.2.3 ECDSA Signature Algorithm
357 // ecdsa-with-SHA1 OBJECT IDENTIFIER ::= {
358 // iso(1) member-body(2) us(840) ansi-x962(10045)
359 // signatures(4) ecdsa-with-SHA1(1)}
361 // RFC 4055 5 PKCS #1 Version 1.5
363 // sha256WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 11 }
365 // sha384WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 12 }
367 // sha512WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 13 }
369 // RFC 5758 3.1 DSA Signature Algorithms
371 // dsaWithSha256 OBJECT IDENTIFIER ::= {
372 // joint-iso-ccitt(2) country(16) us(840) organization(1) gov(101)
373 // csor(3) algorithms(4) id-dsa-with-sha2(3) 2}
375 // RFC 5758 3.2 ECDSA Signature Algorithm
377 // ecdsa-with-SHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
378 // us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 2 }
380 // ecdsa-with-SHA384 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
381 // us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 3 }
383 // ecdsa-with-SHA512 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
384 // us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 4 }
386 // RFC 8410 3 Curve25519 and Curve448 Algorithm Identifiers
388 // id-Ed25519 OBJECT IDENTIFIER ::= { 1 3 101 112 }
390 oidSignatureMD2WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 2}
391 oidSignatureMD5WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 4}
392 oidSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}
393 oidSignatureSHA256WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 11}
394 oidSignatureSHA384WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 12}
395 oidSignatureSHA512WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 13}
396 oidSignatureRSAPSS = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 10}
397 oidSignatureDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 3}
398 oidSignatureDSAWithSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 3, 2}
399 oidSignatureECDSAWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 1}
400 oidSignatureECDSAWithSHA256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 2}
401 oidSignatureECDSAWithSHA384 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 3}
402 oidSignatureECDSAWithSHA512 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 4}
403 oidSignatureEd25519 = asn1.ObjectIdentifier{1, 3, 101, 112}
405 oidTc26Gost341012256 = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 1, 1, 1}
406 oidTc26Gost341012512 = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 1, 1, 2}
407 oidTc26Gost34112012256 = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 1, 2, 2}
408 oidTc26Gost34112012512 = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 1, 2, 3}
409 oidTc26Gost341012256Signature = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 1, 3, 2}
410 oidTc26Gost341012512Signature = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 1, 3, 3}
411 oidGostR34102001CryptoProAParamSet = asn1.ObjectIdentifier{1, 2, 643, 2, 2, 35, 1}
412 oidGostR34102001CryptoProBParamSet = asn1.ObjectIdentifier{1, 2, 643, 2, 2, 35, 2}
413 oidGostR34102001CryptoProCParamSet = asn1.ObjectIdentifier{1, 2, 643, 2, 2, 35, 3}
414 oidGostR34102001CryptoProXchAParamSet = asn1.ObjectIdentifier{1, 2, 643, 2, 2, 36, 0}
415 oidGostR34102001CryptoProXchBParamSet = asn1.ObjectIdentifier{1, 2, 643, 2, 2, 36, 1}
416 oidTc26Gost341012256ParamSetA = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 2, 1, 1, 1}
417 oidTc26Gost341012256ParamSetB = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 2, 1, 1, 2}
418 oidTc26Gost341012256ParamSetC = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 2, 1, 1, 3}
419 oidTc26Gost341012256ParamSetD = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 2, 1, 1, 4}
420 oidTc26Gost341012512ParamSetA = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 2, 1, 2, 1}
421 oidTc26Gost341012512ParamSetB = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 2, 1, 2, 2}
422 oidTc26Gost341012512ParamSetC = asn1.ObjectIdentifier{1, 2, 643, 7, 1, 2, 1, 2, 3}
424 oidSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 1}
425 oidSHA384 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 2}
426 oidSHA512 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 3}
428 oidMGF1 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 8}
430 // oidISOSignatureSHA1WithRSA means the same as oidSignatureSHA1WithRSA
431 // but it's specified by ISO. Microsoft's makecert.exe has been known
432 // to produce certificates with this OID.
433 oidISOSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 3, 14, 3, 2, 29}
436 var signatureAlgorithmDetails = []struct {
437 algo SignatureAlgorithm
439 oid asn1.ObjectIdentifier
440 pubKeyAlgo PublicKeyAlgorithm
443 {MD2WithRSA, "MD2-RSA", oidSignatureMD2WithRSA, RSA, crypto.Hash(0) /* no value for MD2 */},
444 {MD5WithRSA, "MD5-RSA", oidSignatureMD5WithRSA, RSA, crypto.MD5},
445 {SHA1WithRSA, "SHA1-RSA", oidSignatureSHA1WithRSA, RSA, crypto.SHA1},
446 {SHA1WithRSA, "SHA1-RSA", oidISOSignatureSHA1WithRSA, RSA, crypto.SHA1},
447 {SHA256WithRSA, "SHA256-RSA", oidSignatureSHA256WithRSA, RSA, crypto.SHA256},
448 {SHA384WithRSA, "SHA384-RSA", oidSignatureSHA384WithRSA, RSA, crypto.SHA384},
449 {SHA512WithRSA, "SHA512-RSA", oidSignatureSHA512WithRSA, RSA, crypto.SHA512},
450 {SHA256WithRSAPSS, "SHA256-RSAPSS", oidSignatureRSAPSS, RSA, crypto.SHA256},
451 {SHA384WithRSAPSS, "SHA384-RSAPSS", oidSignatureRSAPSS, RSA, crypto.SHA384},
452 {SHA512WithRSAPSS, "SHA512-RSAPSS", oidSignatureRSAPSS, RSA, crypto.SHA512},
453 {DSAWithSHA1, "DSA-SHA1", oidSignatureDSAWithSHA1, DSA, crypto.SHA1},
454 {DSAWithSHA256, "DSA-SHA256", oidSignatureDSAWithSHA256, DSA, crypto.SHA256},
455 {ECDSAWithSHA1, "ECDSA-SHA1", oidSignatureECDSAWithSHA1, ECDSA, crypto.SHA1},
456 {ECDSAWithSHA256, "ECDSA-SHA256", oidSignatureECDSAWithSHA256, ECDSA, crypto.SHA256},
457 {ECDSAWithSHA384, "ECDSA-SHA384", oidSignatureECDSAWithSHA384, ECDSA, crypto.SHA384},
458 {ECDSAWithSHA512, "ECDSA-SHA512", oidSignatureECDSAWithSHA512, ECDSA, crypto.SHA512},
459 {PureEd25519, "Ed25519", oidSignatureEd25519, Ed25519, crypto.Hash(0) /* no pre-hashing */},
460 {GOST256, "GOST256", oidTc26Gost341012256Signature, GOST, crypto.GOSTR34112012256},
461 {GOST512, "GOST512", oidTc26Gost341012512Signature, GOST, crypto.GOSTR34112012512},
464 // hashToPSSParameters contains the DER encoded RSA PSS parameters for the
465 // SHA256, SHA384, and SHA512 hashes as defined in RFC 3447, Appendix A.2.3.
466 // The parameters contain the following values:
467 // - hashAlgorithm contains the associated hash identifier with NULL parameters
468 // - maskGenAlgorithm always contains the default mgf1SHA1 identifier
469 // - saltLength contains the length of the associated hash
470 // - trailerField always contains the default trailerFieldBC value
471 var hashToPSSParameters = map[crypto.Hash]asn1.RawValue{
472 crypto.SHA256: 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}},
473 crypto.SHA384: 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}},
474 crypto.SHA512: 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}},
477 // pssParameters reflects the parameters in an AlgorithmIdentifier that
478 // specifies RSA PSS. See RFC 3447, Appendix A.2.3.
479 type pssParameters struct {
480 // The following three fields are not marked as
481 // optional because the default values specify SHA-1,
482 // which is no longer suitable for use in signatures.
483 Hash pkix.AlgorithmIdentifier `asn1:"explicit,tag:0"`
484 MGF pkix.AlgorithmIdentifier `asn1:"explicit,tag:1"`
485 SaltLength int `asn1:"explicit,tag:2"`
486 TrailerField int `asn1:"optional,explicit,tag:3,default:1"`
489 func getSignatureAlgorithmFromAI(ai pkix.AlgorithmIdentifier) SignatureAlgorithm {
490 if ai.Algorithm.Equal(oidSignatureEd25519) {
491 // RFC 8410, Section 3
492 // > For all of the OIDs, the parameters MUST be absent.
493 if len(ai.Parameters.FullBytes) != 0 {
494 return UnknownSignatureAlgorithm
498 if !ai.Algorithm.Equal(oidSignatureRSAPSS) {
499 for _, details := range signatureAlgorithmDetails {
500 if ai.Algorithm.Equal(details.oid) {
504 return UnknownSignatureAlgorithm
507 // RSA PSS is special because it encodes important parameters
508 // in the Parameters.
510 var params pssParameters
511 if _, err := asn1.Unmarshal(ai.Parameters.FullBytes, ¶ms); err != nil {
512 return UnknownSignatureAlgorithm
515 var mgf1HashFunc pkix.AlgorithmIdentifier
516 if _, err := asn1.Unmarshal(params.MGF.Parameters.FullBytes, &mgf1HashFunc); err != nil {
517 return UnknownSignatureAlgorithm
520 // PSS is greatly overburdened with options. This code forces them into
521 // three buckets by requiring that the MGF1 hash function always match the
522 // message hash function (as recommended in RFC 3447, Section 8.1), that the
523 // salt length matches the hash length, and that the trailer field has the
525 if (len(params.Hash.Parameters.FullBytes) != 0 && !bytes.Equal(params.Hash.Parameters.FullBytes, asn1.NullBytes)) ||
526 !params.MGF.Algorithm.Equal(oidMGF1) ||
527 !mgf1HashFunc.Algorithm.Equal(params.Hash.Algorithm) ||
528 (len(mgf1HashFunc.Parameters.FullBytes) != 0 && !bytes.Equal(mgf1HashFunc.Parameters.FullBytes, asn1.NullBytes)) ||
529 params.TrailerField != 1 {
530 return UnknownSignatureAlgorithm
534 case params.Hash.Algorithm.Equal(oidSHA256) && params.SaltLength == 32:
535 return SHA256WithRSAPSS
536 case params.Hash.Algorithm.Equal(oidSHA384) && params.SaltLength == 48:
537 return SHA384WithRSAPSS
538 case params.Hash.Algorithm.Equal(oidSHA512) && params.SaltLength == 64:
539 return SHA512WithRSAPSS
542 return UnknownSignatureAlgorithm
546 // RFC 3279, 2.3 Public Key Algorithms
548 // pkcs-1 OBJECT IDENTIFIER ::== { iso(1) member-body(2) us(840)
549 // rsadsi(113549) pkcs(1) 1 }
551 // rsaEncryption OBJECT IDENTIFIER ::== { pkcs1-1 1 }
553 // id-dsa OBJECT IDENTIFIER ::== { iso(1) member-body(2) us(840)
554 // x9-57(10040) x9cm(4) 1 }
555 oidPublicKeyRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}
556 oidPublicKeyDSA = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 1}
557 // RFC 5480, 2.1.1 Unrestricted Algorithm Identifier and Parameters
559 // id-ecPublicKey OBJECT IDENTIFIER ::= {
560 // iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 }
561 oidPublicKeyECDSA = asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}
562 // RFC 8410, Section 3
564 // id-X25519 OBJECT IDENTIFIER ::= { 1 3 101 110 }
565 // id-Ed25519 OBJECT IDENTIFIER ::= { 1 3 101 112 }
566 oidPublicKeyX25519 = asn1.ObjectIdentifier{1, 3, 101, 110}
567 oidPublicKeyEd25519 = asn1.ObjectIdentifier{1, 3, 101, 112}
569 oidPublicKeyGOST256 = oidTc26Gost341012256
570 oidPublicKeyGOST512 = oidTc26Gost341012512
573 // getPublicKeyAlgorithmFromOID returns the exposed PublicKeyAlgorithm
574 // identifier for public key types supported in certificates and CSRs. Marshal
575 // and Parse functions may support a different set of public key types.
576 func getPublicKeyAlgorithmFromOID(oid asn1.ObjectIdentifier) PublicKeyAlgorithm {
578 case oid.Equal(oidPublicKeyRSA):
580 case oid.Equal(oidPublicKeyDSA):
582 case oid.Equal(oidPublicKeyECDSA):
584 case oid.Equal(oidPublicKeyEd25519):
586 case oid.Equal(oidPublicKeyGOST256):
588 case oid.Equal(oidPublicKeyGOST512):
591 return UnknownPublicKeyAlgorithm
594 // RFC 5480, 2.1.1.1. Named Curve
596 // secp224r1 OBJECT IDENTIFIER ::= {
597 // iso(1) identified-organization(3) certicom(132) curve(0) 33 }
599 // secp256r1 OBJECT IDENTIFIER ::= {
600 // iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3)
603 // secp384r1 OBJECT IDENTIFIER ::= {
604 // iso(1) identified-organization(3) certicom(132) curve(0) 34 }
606 // secp521r1 OBJECT IDENTIFIER ::= {
607 // iso(1) identified-organization(3) certicom(132) curve(0) 35 }
609 // NB: secp256r1 is equivalent to prime256v1
611 oidNamedCurveP224 = asn1.ObjectIdentifier{1, 3, 132, 0, 33}
612 oidNamedCurveP256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 3, 1, 7}
613 oidNamedCurveP384 = asn1.ObjectIdentifier{1, 3, 132, 0, 34}
614 oidNamedCurveP521 = asn1.ObjectIdentifier{1, 3, 132, 0, 35}
617 func namedCurveFromOID(oid asn1.ObjectIdentifier) elliptic.Curve {
619 case oid.Equal(oidNamedCurveP224):
620 return elliptic.P224()
621 case oid.Equal(oidNamedCurveP256):
622 return elliptic.P256()
623 case oid.Equal(oidNamedCurveP384):
624 return elliptic.P384()
625 case oid.Equal(oidNamedCurveP521):
626 return elliptic.P521()
631 func oidFromNamedCurve(curve elliptic.Curve) (asn1.ObjectIdentifier, bool) {
633 case elliptic.P224():
634 return oidNamedCurveP224, true
635 case elliptic.P256():
636 return oidNamedCurveP256, true
637 case elliptic.P384():
638 return oidNamedCurveP384, true
639 case elliptic.P521():
640 return oidNamedCurveP521, true
646 func oidFromECDHCurve(curve ecdh.Curve) (asn1.ObjectIdentifier, bool) {
649 return oidPublicKeyX25519, true
651 return oidNamedCurveP256, true
653 return oidNamedCurveP384, true
655 return oidNamedCurveP521, true
661 // KeyUsage represents the set of actions that are valid for a given key. It's
662 // a bitmap of the KeyUsage* constants.
666 KeyUsageDigitalSignature KeyUsage = 1 << iota
667 KeyUsageContentCommitment
668 KeyUsageKeyEncipherment
669 KeyUsageDataEncipherment
677 // RFC 5280, 4.2.1.12 Extended Key Usage
679 // anyExtendedKeyUsage OBJECT IDENTIFIER ::= { id-ce-extKeyUsage 0 }
681 // id-kp OBJECT IDENTIFIER ::= { id-pkix 3 }
683 // id-kp-serverAuth OBJECT IDENTIFIER ::= { id-kp 1 }
684 // id-kp-clientAuth OBJECT IDENTIFIER ::= { id-kp 2 }
685 // id-kp-codeSigning OBJECT IDENTIFIER ::= { id-kp 3 }
686 // id-kp-emailProtection OBJECT IDENTIFIER ::= { id-kp 4 }
687 // id-kp-timeStamping OBJECT IDENTIFIER ::= { id-kp 8 }
688 // id-kp-OCSPSigning OBJECT IDENTIFIER ::= { id-kp 9 }
690 oidExtKeyUsageAny = asn1.ObjectIdentifier{2, 5, 29, 37, 0}
691 oidExtKeyUsageServerAuth = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 1}
692 oidExtKeyUsageClientAuth = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 2}
693 oidExtKeyUsageCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 3}
694 oidExtKeyUsageEmailProtection = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 4}
695 oidExtKeyUsageIPSECEndSystem = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 5}
696 oidExtKeyUsageIPSECTunnel = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 6}
697 oidExtKeyUsageIPSECUser = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 7}
698 oidExtKeyUsageTimeStamping = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 8}
699 oidExtKeyUsageOCSPSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 9}
700 oidExtKeyUsageMicrosoftServerGatedCrypto = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 10, 3, 3}
701 oidExtKeyUsageNetscapeServerGatedCrypto = asn1.ObjectIdentifier{2, 16, 840, 1, 113730, 4, 1}
702 oidExtKeyUsageMicrosoftCommercialCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 2, 1, 22}
703 oidExtKeyUsageMicrosoftKernelCodeSigning = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 311, 61, 1, 1}
706 // ExtKeyUsage represents an extended set of actions that are valid for a given key.
707 // Each of the ExtKeyUsage* constants define a unique action.
711 ExtKeyUsageAny ExtKeyUsage = iota
712 ExtKeyUsageServerAuth
713 ExtKeyUsageClientAuth
714 ExtKeyUsageCodeSigning
715 ExtKeyUsageEmailProtection
716 ExtKeyUsageIPSECEndSystem
717 ExtKeyUsageIPSECTunnel
719 ExtKeyUsageTimeStamping
720 ExtKeyUsageOCSPSigning
721 ExtKeyUsageMicrosoftServerGatedCrypto
722 ExtKeyUsageNetscapeServerGatedCrypto
723 ExtKeyUsageMicrosoftCommercialCodeSigning
724 ExtKeyUsageMicrosoftKernelCodeSigning
727 // extKeyUsageOIDs contains the mapping between an ExtKeyUsage and its OID.
728 var extKeyUsageOIDs = []struct {
729 extKeyUsage ExtKeyUsage
730 oid asn1.ObjectIdentifier
732 {ExtKeyUsageAny, oidExtKeyUsageAny},
733 {ExtKeyUsageServerAuth, oidExtKeyUsageServerAuth},
734 {ExtKeyUsageClientAuth, oidExtKeyUsageClientAuth},
735 {ExtKeyUsageCodeSigning, oidExtKeyUsageCodeSigning},
736 {ExtKeyUsageEmailProtection, oidExtKeyUsageEmailProtection},
737 {ExtKeyUsageIPSECEndSystem, oidExtKeyUsageIPSECEndSystem},
738 {ExtKeyUsageIPSECTunnel, oidExtKeyUsageIPSECTunnel},
739 {ExtKeyUsageIPSECUser, oidExtKeyUsageIPSECUser},
740 {ExtKeyUsageTimeStamping, oidExtKeyUsageTimeStamping},
741 {ExtKeyUsageOCSPSigning, oidExtKeyUsageOCSPSigning},
742 {ExtKeyUsageMicrosoftServerGatedCrypto, oidExtKeyUsageMicrosoftServerGatedCrypto},
743 {ExtKeyUsageNetscapeServerGatedCrypto, oidExtKeyUsageNetscapeServerGatedCrypto},
744 {ExtKeyUsageMicrosoftCommercialCodeSigning, oidExtKeyUsageMicrosoftCommercialCodeSigning},
745 {ExtKeyUsageMicrosoftKernelCodeSigning, oidExtKeyUsageMicrosoftKernelCodeSigning},
748 func extKeyUsageFromOID(oid asn1.ObjectIdentifier) (eku ExtKeyUsage, ok bool) {
749 for _, pair := range extKeyUsageOIDs {
750 if oid.Equal(pair.oid) {
751 return pair.extKeyUsage, true
757 func oidFromExtKeyUsage(eku ExtKeyUsage) (oid asn1.ObjectIdentifier, ok bool) {
758 for _, pair := range extKeyUsageOIDs {
759 if eku == pair.extKeyUsage {
760 return pair.oid, true
766 // A Certificate represents an X.509 certificate.
767 type Certificate struct {
768 Raw []byte // Complete ASN.1 DER content (certificate, signature algorithm and signature).
769 RawTBSCertificate []byte // Certificate part of raw ASN.1 DER content.
770 RawSubjectPublicKeyInfo []byte // DER encoded SubjectPublicKeyInfo.
771 RawSubject []byte // DER encoded Subject
772 RawIssuer []byte // DER encoded Issuer
775 SignatureAlgorithm SignatureAlgorithm
777 PublicKeyAlgorithm PublicKeyAlgorithm
781 SerialNumber *big.Int
784 NotBefore, NotAfter time.Time // Validity bounds.
787 // Extensions contains raw X.509 extensions. When parsing certificates,
788 // this can be used to extract non-critical extensions that are not
789 // parsed by this package. When marshaling certificates, the Extensions
790 // field is ignored, see ExtraExtensions.
791 Extensions []pkix.Extension
793 // ExtraExtensions contains extensions to be copied, raw, into any
794 // marshaled certificates. Values override any extensions that would
795 // otherwise be produced based on the other fields. The ExtraExtensions
796 // field is not populated when parsing certificates, see Extensions.
797 ExtraExtensions []pkix.Extension
799 // UnhandledCriticalExtensions contains a list of extension IDs that
800 // were not (fully) processed when parsing. Verify will fail if this
801 // slice is non-empty, unless verification is delegated to an OS
802 // library which understands all the critical extensions.
804 // Users can access these extensions using Extensions and can remove
805 // elements from this slice if they believe that they have been
807 UnhandledCriticalExtensions []asn1.ObjectIdentifier
809 ExtKeyUsage []ExtKeyUsage // Sequence of extended key usages.
810 UnknownExtKeyUsage []asn1.ObjectIdentifier // Encountered extended key usages unknown to this package.
812 // BasicConstraintsValid indicates whether IsCA, MaxPathLen,
813 // and MaxPathLenZero are valid.
814 BasicConstraintsValid bool
817 // MaxPathLen and MaxPathLenZero indicate the presence and
818 // value of the BasicConstraints' "pathLenConstraint".
820 // When parsing a certificate, a positive non-zero MaxPathLen
821 // means that the field was specified, -1 means it was unset,
822 // and MaxPathLenZero being true mean that the field was
823 // explicitly set to zero. The case of MaxPathLen==0 with MaxPathLenZero==false
824 // should be treated equivalent to -1 (unset).
826 // When generating a certificate, an unset pathLenConstraint
827 // can be requested with either MaxPathLen == -1 or using the
828 // zero value for both MaxPathLen and MaxPathLenZero.
830 // MaxPathLenZero indicates that BasicConstraintsValid==true
831 // and MaxPathLen==0 should be interpreted as an actual
832 // maximum path length of zero. Otherwise, that combination is
833 // interpreted as MaxPathLen not being set.
837 AuthorityKeyId []byte
839 // RFC 5280, 4.2.2.1 (Authority Information Access)
841 IssuingCertificateURL []string
843 // Subject Alternate Name values. (Note that these values may not be valid
844 // if invalid values were contained within a parsed certificate. For
845 // example, an element of DNSNames may not be a valid DNS domain name.)
847 EmailAddresses []string
852 PermittedDNSDomainsCritical bool // if true then the name constraints are marked critical.
853 PermittedDNSDomains []string
854 ExcludedDNSDomains []string
855 PermittedIPRanges []*net.IPNet
856 ExcludedIPRanges []*net.IPNet
857 PermittedEmailAddresses []string
858 ExcludedEmailAddresses []string
859 PermittedURIDomains []string
860 ExcludedURIDomains []string
862 // CRL Distribution Points
863 CRLDistributionPoints []string
865 PolicyIdentifiers []asn1.ObjectIdentifier
868 // ErrUnsupportedAlgorithm results from attempting to perform an operation that
869 // involves algorithms that are not currently implemented.
870 var ErrUnsupportedAlgorithm = errors.New("x509: cannot verify signature: algorithm unimplemented")
872 // An InsecureAlgorithmError indicates that the SignatureAlgorithm used to
873 // generate the signature is not secure, and the signature has been rejected.
875 // To temporarily restore support for SHA-1 signatures, include the value
876 // "x509sha1=1" in the GODEBUG environment variable. Note that this option will
877 // be removed in a future release.
878 type InsecureAlgorithmError SignatureAlgorithm
880 func (e InsecureAlgorithmError) Error() string {
882 if SignatureAlgorithm(e) == SHA1WithRSA || SignatureAlgorithm(e) == ECDSAWithSHA1 {
883 override = " (temporarily override with GODEBUG=x509sha1=1)"
885 return fmt.Sprintf("x509: cannot verify signature: insecure algorithm %v", SignatureAlgorithm(e)) + override
888 // ConstraintViolationError results when a requested usage is not permitted by
889 // a certificate. For example: checking a signature when the public key isn't a
890 // certificate signing key.
891 type ConstraintViolationError struct{}
893 func (ConstraintViolationError) Error() string {
894 return "x509: invalid signature: parent certificate cannot sign this kind of certificate"
897 func (c *Certificate) Equal(other *Certificate) bool {
898 if c == nil || other == nil {
901 return bytes.Equal(c.Raw, other.Raw)
904 func (c *Certificate) hasSANExtension() bool {
905 return oidInExtensions(oidExtensionSubjectAltName, c.Extensions)
908 // CheckSignatureFrom verifies that the signature on c is a valid signature from parent.
910 // This is a low-level API that performs very limited checks, and not a full
911 // path verifier. Most users should use [Certificate.Verify] instead.
912 func (c *Certificate) CheckSignatureFrom(parent *Certificate) error {
913 // RFC 5280, 4.2.1.9:
914 // "If the basic constraints extension is not present in a version 3
915 // certificate, or the extension is present but the cA boolean is not
916 // asserted, then the certified public key MUST NOT be used to verify
917 // certificate signatures."
918 if parent.Version == 3 && !parent.BasicConstraintsValid ||
919 parent.BasicConstraintsValid && !parent.IsCA {
920 return ConstraintViolationError{}
923 if parent.KeyUsage != 0 && parent.KeyUsage&KeyUsageCertSign == 0 {
924 return ConstraintViolationError{}
927 if parent.PublicKeyAlgorithm == UnknownPublicKeyAlgorithm {
928 return ErrUnsupportedAlgorithm
931 return checkSignature(c.SignatureAlgorithm, c.RawTBSCertificate, c.Signature, parent.PublicKey, false)
934 // CheckSignature verifies that signature is a valid signature over signed from
937 // This is a low-level API that performs no validity checks on the certificate.
939 // [MD5WithRSA] signatures are rejected, while [SHA1WithRSA] and [ECDSAWithSHA1]
940 // signatures are currently accepted.
941 func (c *Certificate) CheckSignature(algo SignatureAlgorithm, signed, signature []byte) error {
942 return checkSignature(algo, signed, signature, c.PublicKey, true)
945 func (c *Certificate) hasNameConstraints() bool {
946 return oidInExtensions(oidExtensionNameConstraints, c.Extensions)
949 func (c *Certificate) getSANExtension() []byte {
950 for _, e := range c.Extensions {
951 if e.Id.Equal(oidExtensionSubjectAltName) {
958 func signaturePublicKeyAlgoMismatchError(expectedPubKeyAlgo PublicKeyAlgorithm, pubKey any) error {
959 return fmt.Errorf("x509: signature algorithm specifies an %s public key, but have public key of type %T", expectedPubKeyAlgo.String(), pubKey)
962 var x509sha1 = godebug.New("x509sha1")
964 // checkSignature verifies that signature is a valid signature over signed from
965 // a crypto.PublicKey.
966 func checkSignature(algo SignatureAlgorithm, signed, signature []byte, publicKey crypto.PublicKey, allowSHA1 bool) (err error) {
967 var hashType crypto.Hash
968 var pubKeyAlgo PublicKeyAlgorithm
970 for _, details := range signatureAlgorithmDetails {
971 if details.algo == algo {
972 hashType = details.hash
973 pubKeyAlgo = details.pubKeyAlgo
979 if pubKeyAlgo != Ed25519 {
980 return ErrUnsupportedAlgorithm
983 return InsecureAlgorithmError(algo)
985 // SHA-1 signatures are mostly disabled. See go.dev/issue/41682.
986 if !allowSHA1 && x509sha1.Value() != "1" {
987 return InsecureAlgorithmError(algo)
991 if !hashType.Available() {
992 return ErrUnsupportedAlgorithm
999 switch pub := publicKey.(type) {
1000 case *rsa.PublicKey:
1001 if pubKeyAlgo != RSA {
1002 return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)
1004 if algo.isRSAPSS() {
1005 return rsa.VerifyPSS(pub, hashType, signed, signature, &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash})
1007 return rsa.VerifyPKCS1v15(pub, hashType, signed, signature)
1009 case *ecdsa.PublicKey:
1010 if pubKeyAlgo != ECDSA {
1011 return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)
1013 if !ecdsa.VerifyASN1(pub, signed, signature) {
1014 return errors.New("x509: ECDSA verification failure")
1017 case ed25519.PublicKey:
1018 if pubKeyAlgo != Ed25519 {
1019 return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)
1021 if !ed25519.Verify(pub, signed, signature) {
1022 return errors.New("x509: Ed25519 verification failure")
1025 case *gost3410.PublicKey:
1026 if pubKeyAlgo != GOST {
1027 return signaturePublicKeyAlgoMismatchError(pubKeyAlgo, pub)
1029 ok, err := gost3410.PublicKeyReverseDigest{Pub: pub}.VerifyDigest(signed, signature)
1034 return errors.New("x509: GOST verification failure")
1038 return ErrUnsupportedAlgorithm
1041 // CheckCRLSignature checks that the signature in crl is from c.
1043 // Deprecated: Use RevocationList.CheckSignatureFrom instead.
1044 func (c *Certificate) CheckCRLSignature(crl *pkix.CertificateList) error {
1045 algo := getSignatureAlgorithmFromAI(crl.SignatureAlgorithm)
1046 return c.CheckSignature(algo, crl.TBSCertList.Raw, crl.SignatureValue.RightAlign())
1049 type UnhandledCriticalExtension struct{}
1051 func (h UnhandledCriticalExtension) Error() string {
1052 return "x509: unhandled critical extension"
1055 type basicConstraints struct {
1056 IsCA bool `asn1:"optional"`
1057 MaxPathLen int `asn1:"optional,default:-1"`
1061 type policyInformation struct {
1062 Policy asn1.ObjectIdentifier
1063 // policyQualifiers omitted
1073 // RFC 5280, 4.2.2.1
1074 type authorityInfoAccess struct {
1075 Method asn1.ObjectIdentifier
1076 Location asn1.RawValue
1079 // RFC 5280, 4.2.1.14
1080 type distributionPoint struct {
1081 DistributionPoint distributionPointName `asn1:"optional,tag:0"`
1082 Reason asn1.BitString `asn1:"optional,tag:1"`
1083 CRLIssuer asn1.RawValue `asn1:"optional,tag:2"`
1086 type distributionPointName struct {
1087 FullName []asn1.RawValue `asn1:"optional,tag:0"`
1088 RelativeName pkix.RDNSequence `asn1:"optional,tag:1"`
1091 func reverseBitsInAByte(in byte) byte {
1093 b2 := b1>>2&0x33 | b1<<2&0xcc
1094 b3 := b2>>1&0x55 | b2<<1&0xaa
1098 // asn1BitLength returns the bit-length of bitString by considering the
1099 // most-significant bit in a byte to be the "first" bit. This convention
1100 // matches ASN.1, but differs from almost everything else.
1101 func asn1BitLength(bitString []byte) int {
1102 bitLen := len(bitString) * 8
1104 for i := range bitString {
1105 b := bitString[len(bitString)-i-1]
1107 for bit := uint(0); bit < 8; bit++ {
1108 if (b>>bit)&1 == 1 {
1119 oidExtensionSubjectKeyId = []int{2, 5, 29, 14}
1120 oidExtensionKeyUsage = []int{2, 5, 29, 15}
1121 oidExtensionExtendedKeyUsage = []int{2, 5, 29, 37}
1122 oidExtensionAuthorityKeyId = []int{2, 5, 29, 35}
1123 oidExtensionBasicConstraints = []int{2, 5, 29, 19}
1124 oidExtensionSubjectAltName = []int{2, 5, 29, 17}
1125 oidExtensionCertificatePolicies = []int{2, 5, 29, 32}
1126 oidExtensionNameConstraints = []int{2, 5, 29, 30}
1127 oidExtensionCRLDistributionPoints = []int{2, 5, 29, 31}
1128 oidExtensionAuthorityInfoAccess = []int{1, 3, 6, 1, 5, 5, 7, 1, 1}
1129 oidExtensionCRLNumber = []int{2, 5, 29, 20}
1133 oidAuthorityInfoAccessOcsp = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 1}
1134 oidAuthorityInfoAccessIssuers = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 2}
1137 // oidInExtensions reports whether an extension with the given oid exists in
1139 func oidInExtensions(oid asn1.ObjectIdentifier, extensions []pkix.Extension) bool {
1140 for _, e := range extensions {
1141 if e.Id.Equal(oid) {
1148 // marshalSANs marshals a list of addresses into a the contents of an X.509
1149 // SubjectAlternativeName extension.
1150 func marshalSANs(dnsNames, emailAddresses []string, ipAddresses []net.IP, uris []*url.URL) (derBytes []byte, err error) {
1151 var rawValues []asn1.RawValue
1152 for _, name := range dnsNames {
1153 if err := isIA5String(name); err != nil {
1156 rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeDNS, Class: 2, Bytes: []byte(name)})
1158 for _, email := range emailAddresses {
1159 if err := isIA5String(email); err != nil {
1162 rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeEmail, Class: 2, Bytes: []byte(email)})
1164 for _, rawIP := range ipAddresses {
1165 // If possible, we always want to encode IPv4 addresses in 4 bytes.
1170 rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeIP, Class: 2, Bytes: ip})
1172 for _, uri := range uris {
1173 uriStr := uri.String()
1174 if err := isIA5String(uriStr); err != nil {
1177 rawValues = append(rawValues, asn1.RawValue{Tag: nameTypeURI, Class: 2, Bytes: []byte(uriStr)})
1179 return asn1.Marshal(rawValues)
1182 func isIA5String(s string) error {
1183 for _, r := range s {
1184 // Per RFC5280 "IA5String is limited to the set of ASCII characters"
1185 if r > unicode.MaxASCII {
1186 return fmt.Errorf("x509: %q cannot be encoded as an IA5String", s)
1193 func buildCertExtensions(template *Certificate, subjectIsEmpty bool, authorityKeyId []byte, subjectKeyId []byte) (ret []pkix.Extension, err error) {
1194 ret = make([]pkix.Extension, 10 /* maximum number of elements. */)
1197 if template.KeyUsage != 0 &&
1198 !oidInExtensions(oidExtensionKeyUsage, template.ExtraExtensions) {
1199 ret[n], err = marshalKeyUsage(template.KeyUsage)
1206 if (len(template.ExtKeyUsage) > 0 || len(template.UnknownExtKeyUsage) > 0) &&
1207 !oidInExtensions(oidExtensionExtendedKeyUsage, template.ExtraExtensions) {
1208 ret[n], err = marshalExtKeyUsage(template.ExtKeyUsage, template.UnknownExtKeyUsage)
1215 if template.BasicConstraintsValid && !oidInExtensions(oidExtensionBasicConstraints, template.ExtraExtensions) {
1216 ret[n], err = marshalBasicConstraints(template.IsCA, template.MaxPathLen, template.MaxPathLenZero)
1223 if len(subjectKeyId) > 0 && !oidInExtensions(oidExtensionSubjectKeyId, template.ExtraExtensions) {
1224 ret[n].Id = oidExtensionSubjectKeyId
1225 ret[n].Value, err = asn1.Marshal(subjectKeyId)
1232 if len(authorityKeyId) > 0 && !oidInExtensions(oidExtensionAuthorityKeyId, template.ExtraExtensions) {
1233 ret[n].Id = oidExtensionAuthorityKeyId
1234 ret[n].Value, err = asn1.Marshal(authKeyId{authorityKeyId})
1241 if (len(template.OCSPServer) > 0 || len(template.IssuingCertificateURL) > 0) &&
1242 !oidInExtensions(oidExtensionAuthorityInfoAccess, template.ExtraExtensions) {
1243 ret[n].Id = oidExtensionAuthorityInfoAccess
1244 var aiaValues []authorityInfoAccess
1245 for _, name := range template.OCSPServer {
1246 aiaValues = append(aiaValues, authorityInfoAccess{
1247 Method: oidAuthorityInfoAccessOcsp,
1248 Location: asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)},
1251 for _, name := range template.IssuingCertificateURL {
1252 aiaValues = append(aiaValues, authorityInfoAccess{
1253 Method: oidAuthorityInfoAccessIssuers,
1254 Location: asn1.RawValue{Tag: 6, Class: 2, Bytes: []byte(name)},
1257 ret[n].Value, err = asn1.Marshal(aiaValues)
1264 if (len(template.DNSNames) > 0 || len(template.EmailAddresses) > 0 || len(template.IPAddresses) > 0 || len(template.URIs) > 0) &&
1265 !oidInExtensions(oidExtensionSubjectAltName, template.ExtraExtensions) {
1266 ret[n].Id = oidExtensionSubjectAltName
1267 // From RFC 5280, Section 4.2.1.6:
1268 // “If the subject field contains an empty sequence ... then
1269 // subjectAltName extension ... is marked as critical”
1270 ret[n].Critical = subjectIsEmpty
1271 ret[n].Value, err = marshalSANs(template.DNSNames, template.EmailAddresses, template.IPAddresses, template.URIs)
1278 if len(template.PolicyIdentifiers) > 0 &&
1279 !oidInExtensions(oidExtensionCertificatePolicies, template.ExtraExtensions) {
1280 ret[n], err = marshalCertificatePolicies(template.PolicyIdentifiers)
1287 if (len(template.PermittedDNSDomains) > 0 || len(template.ExcludedDNSDomains) > 0 ||
1288 len(template.PermittedIPRanges) > 0 || len(template.ExcludedIPRanges) > 0 ||
1289 len(template.PermittedEmailAddresses) > 0 || len(template.ExcludedEmailAddresses) > 0 ||
1290 len(template.PermittedURIDomains) > 0 || len(template.ExcludedURIDomains) > 0) &&
1291 !oidInExtensions(oidExtensionNameConstraints, template.ExtraExtensions) {
1292 ret[n].Id = oidExtensionNameConstraints
1293 ret[n].Critical = template.PermittedDNSDomainsCritical
1295 ipAndMask := func(ipNet *net.IPNet) []byte {
1296 maskedIP := ipNet.IP.Mask(ipNet.Mask)
1297 ipAndMask := make([]byte, 0, len(maskedIP)+len(ipNet.Mask))
1298 ipAndMask = append(ipAndMask, maskedIP...)
1299 ipAndMask = append(ipAndMask, ipNet.Mask...)
1303 serialiseConstraints := func(dns []string, ips []*net.IPNet, emails []string, uriDomains []string) (der []byte, err error) {
1304 var b cryptobyte.Builder
1306 for _, name := range dns {
1307 if err = isIA5String(name); err != nil {
1311 b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
1312 b.AddASN1(cryptobyte_asn1.Tag(2).ContextSpecific(), func(b *cryptobyte.Builder) {
1313 b.AddBytes([]byte(name))
1318 for _, ipNet := range ips {
1319 b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
1320 b.AddASN1(cryptobyte_asn1.Tag(7).ContextSpecific(), func(b *cryptobyte.Builder) {
1321 b.AddBytes(ipAndMask(ipNet))
1326 for _, email := range emails {
1327 if err = isIA5String(email); err != nil {
1331 b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
1332 b.AddASN1(cryptobyte_asn1.Tag(1).ContextSpecific(), func(b *cryptobyte.Builder) {
1333 b.AddBytes([]byte(email))
1338 for _, uriDomain := range uriDomains {
1339 if err = isIA5String(uriDomain); err != nil {
1343 b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
1344 b.AddASN1(cryptobyte_asn1.Tag(6).ContextSpecific(), func(b *cryptobyte.Builder) {
1345 b.AddBytes([]byte(uriDomain))
1353 permitted, err := serialiseConstraints(template.PermittedDNSDomains, template.PermittedIPRanges, template.PermittedEmailAddresses, template.PermittedURIDomains)
1358 excluded, err := serialiseConstraints(template.ExcludedDNSDomains, template.ExcludedIPRanges, template.ExcludedEmailAddresses, template.ExcludedURIDomains)
1363 var b cryptobyte.Builder
1364 b.AddASN1(cryptobyte_asn1.SEQUENCE, func(b *cryptobyte.Builder) {
1365 if len(permitted) > 0 {
1366 b.AddASN1(cryptobyte_asn1.Tag(0).ContextSpecific().Constructed(), func(b *cryptobyte.Builder) {
1367 b.AddBytes(permitted)
1371 if len(excluded) > 0 {
1372 b.AddASN1(cryptobyte_asn1.Tag(1).ContextSpecific().Constructed(), func(b *cryptobyte.Builder) {
1373 b.AddBytes(excluded)
1378 ret[n].Value, err = b.Bytes()
1385 if len(template.CRLDistributionPoints) > 0 &&
1386 !oidInExtensions(oidExtensionCRLDistributionPoints, template.ExtraExtensions) {
1387 ret[n].Id = oidExtensionCRLDistributionPoints
1389 var crlDp []distributionPoint
1390 for _, name := range template.CRLDistributionPoints {
1391 dp := distributionPoint{
1392 DistributionPoint: distributionPointName{
1393 FullName: []asn1.RawValue{
1394 {Tag: 6, Class: 2, Bytes: []byte(name)},
1398 crlDp = append(crlDp, dp)
1401 ret[n].Value, err = asn1.Marshal(crlDp)
1408 // Adding another extension here? Remember to update the maximum number
1409 // of elements in the make() at the top of the function and the list of
1410 // template fields used in CreateCertificate documentation.
1412 return append(ret[:n], template.ExtraExtensions...), nil
1415 func marshalKeyUsage(ku KeyUsage) (pkix.Extension, error) {
1416 ext := pkix.Extension{Id: oidExtensionKeyUsage, Critical: true}
1419 a[0] = reverseBitsInAByte(byte(ku))
1420 a[1] = reverseBitsInAByte(byte(ku >> 8))
1429 ext.Value, err = asn1.Marshal(asn1.BitString{Bytes: bitString, BitLength: asn1BitLength(bitString)})
1433 func marshalExtKeyUsage(extUsages []ExtKeyUsage, unknownUsages []asn1.ObjectIdentifier) (pkix.Extension, error) {
1434 ext := pkix.Extension{Id: oidExtensionExtendedKeyUsage}
1436 oids := make([]asn1.ObjectIdentifier, len(extUsages)+len(unknownUsages))
1437 for i, u := range extUsages {
1438 if oid, ok := oidFromExtKeyUsage(u); ok {
1441 return ext, errors.New("x509: unknown extended key usage")
1445 copy(oids[len(extUsages):], unknownUsages)
1448 ext.Value, err = asn1.Marshal(oids)
1452 func marshalBasicConstraints(isCA bool, maxPathLen int, maxPathLenZero bool) (pkix.Extension, error) {
1453 ext := pkix.Extension{Id: oidExtensionBasicConstraints, Critical: true}
1454 // Leaving MaxPathLen as zero indicates that no maximum path
1455 // length is desired, unless MaxPathLenZero is set. A value of
1456 // -1 causes encoding/asn1 to omit the value as desired.
1457 if maxPathLen == 0 && !maxPathLenZero {
1461 ext.Value, err = asn1.Marshal(basicConstraints{isCA, maxPathLen})
1465 func marshalCertificatePolicies(policyIdentifiers []asn1.ObjectIdentifier) (pkix.Extension, error) {
1466 ext := pkix.Extension{Id: oidExtensionCertificatePolicies}
1467 policies := make([]policyInformation, len(policyIdentifiers))
1468 for i, policy := range policyIdentifiers {
1469 policies[i].Policy = policy
1472 ext.Value, err = asn1.Marshal(policies)
1476 func buildCSRExtensions(template *CertificateRequest) ([]pkix.Extension, error) {
1477 var ret []pkix.Extension
1479 if (len(template.DNSNames) > 0 || len(template.EmailAddresses) > 0 || len(template.IPAddresses) > 0 || len(template.URIs) > 0) &&
1480 !oidInExtensions(oidExtensionSubjectAltName, template.ExtraExtensions) {
1481 sanBytes, err := marshalSANs(template.DNSNames, template.EmailAddresses, template.IPAddresses, template.URIs)
1486 ret = append(ret, pkix.Extension{
1487 Id: oidExtensionSubjectAltName,
1492 return append(ret, template.ExtraExtensions...), nil
1495 func subjectBytes(cert *Certificate) ([]byte, error) {
1496 if len(cert.RawSubject) > 0 {
1497 return cert.RawSubject, nil
1500 return asn1.Marshal(cert.Subject.ToRDNSequence())
1503 // signingParamsForPublicKey returns the parameters to use for signing with
1504 // priv. If requestedSigAlgo is not zero then it overrides the default
1505 // signature algorithm.
1506 func signingParamsForPublicKey(pub any, requestedSigAlgo SignatureAlgorithm) (hashFunc crypto.Hash, sigAlgo pkix.AlgorithmIdentifier, err error) {
1507 var pubType PublicKeyAlgorithm
1509 switch pub := pub.(type) {
1510 case *rsa.PublicKey:
1512 hashFunc = crypto.SHA256
1513 sigAlgo.Algorithm = oidSignatureSHA256WithRSA
1514 sigAlgo.Parameters = asn1.NullRawValue
1516 case *ecdsa.PublicKey:
1520 case elliptic.P224(), elliptic.P256():
1521 hashFunc = crypto.SHA256
1522 sigAlgo.Algorithm = oidSignatureECDSAWithSHA256
1523 case elliptic.P384():
1524 hashFunc = crypto.SHA384
1525 sigAlgo.Algorithm = oidSignatureECDSAWithSHA384
1526 case elliptic.P521():
1527 hashFunc = crypto.SHA512
1528 sigAlgo.Algorithm = oidSignatureECDSAWithSHA512
1530 err = errors.New("x509: unknown elliptic curve")
1533 case ed25519.PublicKey:
1535 sigAlgo.Algorithm = oidSignatureEd25519
1537 case *gost3410.PublicKey:
1539 switch pub.C.PointSize() {
1541 hashFunc = crypto.GOSTR34112012256
1542 sigAlgo.Algorithm = oidTc26Gost341012256Signature
1544 hashFunc = crypto.GOSTR34112012512
1545 sigAlgo.Algorithm = oidTc26Gost341012512Signature
1549 err = errors.New("x509: only RSA, ECDSA, Ed25519 and GOST keys supported")
1556 if requestedSigAlgo == 0 {
1561 for _, details := range signatureAlgorithmDetails {
1562 if details.algo == requestedSigAlgo {
1563 if details.pubKeyAlgo != pubType {
1564 err = errors.New("x509: requested SignatureAlgorithm does not match private key type")
1567 sigAlgo.Algorithm, hashFunc = details.oid, details.hash
1568 if hashFunc == 0 && pubType != Ed25519 {
1569 err = errors.New("x509: cannot sign with hash function requested")
1572 if hashFunc == crypto.MD5 {
1573 err = errors.New("x509: signing with MD5 is not supported")
1576 if requestedSigAlgo.isRSAPSS() {
1577 sigAlgo.Parameters = hashToPSSParameters[hashFunc]
1585 err = errors.New("x509: unknown SignatureAlgorithm")
1591 // emptyASN1Subject is the ASN.1 DER encoding of an empty Subject, which is
1592 // just an empty SEQUENCE.
1593 var emptyASN1Subject = []byte{0x30, 0}
1595 // CreateCertificate creates a new X.509 v3 certificate based on a template.
1596 // The following members of template are currently used:
1599 // - BasicConstraintsValid
1600 // - CRLDistributionPoints
1603 // - ExcludedDNSDomains
1604 // - ExcludedEmailAddresses
1605 // - ExcludedIPRanges
1606 // - ExcludedURIDomains
1608 // - ExtraExtensions
1611 // - IssuingCertificateURL
1618 // - PermittedDNSDomains
1619 // - PermittedDNSDomainsCritical
1620 // - PermittedEmailAddresses
1621 // - PermittedIPRanges
1622 // - PermittedURIDomains
1623 // - PolicyIdentifiers
1625 // - SignatureAlgorithm
1629 // - UnknownExtKeyUsage
1631 // The certificate is signed by parent. If parent is equal to template then the
1632 // certificate is self-signed. The parameter pub is the public key of the
1633 // certificate to be generated and priv is the private key of the signer.
1635 // The returned slice is the certificate in DER encoding.
1637 // The currently supported key types are *rsa.PublicKey, *ecdsa.PublicKey and
1638 // ed25519.PublicKey. pub must be a supported key type, and priv must be a
1639 // crypto.Signer with a supported public key.
1641 // The AuthorityKeyId will be taken from the SubjectKeyId of parent, if any,
1642 // unless the resulting certificate is self-signed. Otherwise the value from
1643 // template will be used.
1645 // If SubjectKeyId from template is empty and the template is a CA, SubjectKeyId
1646 // will be generated from the hash of the public key.
1647 func CreateCertificate(rand io.Reader, template, parent *Certificate, pub, priv any) ([]byte, error) {
1648 key, ok := priv.(crypto.Signer)
1650 return nil, errors.New("x509: certificate private key does not implement crypto.Signer")
1653 if template.SerialNumber == nil {
1654 return nil, errors.New("x509: no SerialNumber given")
1657 // RFC 5280 Section 4.1.2.2: serial number must positive
1659 // We _should_ also restrict serials to <= 20 octets, but it turns out a lot of people
1660 // get this wrong, in part because the encoding can itself alter the length of the
1661 // serial. For now we accept these non-conformant serials.
1662 if template.SerialNumber.Sign() == -1 {
1663 return nil, errors.New("x509: serial number must be positive")
1666 if template.BasicConstraintsValid && !template.IsCA && template.MaxPathLen != -1 && (template.MaxPathLen != 0 || template.MaxPathLenZero) {
1667 return nil, errors.New("x509: only CAs are allowed to specify MaxPathLen")
1670 hashFunc, signatureAlgorithm, err := signingParamsForPublicKey(key.Public(), template.SignatureAlgorithm)
1675 publicKeyBytes, publicKeyAlgorithm, err := marshalPublicKey(pub)
1679 if getPublicKeyAlgorithmFromOID(publicKeyAlgorithm.Algorithm) == UnknownPublicKeyAlgorithm {
1680 return nil, fmt.Errorf("x509: unsupported public key type: %T", pub)
1683 asn1Issuer, err := subjectBytes(parent)
1688 asn1Subject, err := subjectBytes(template)
1693 authorityKeyId := template.AuthorityKeyId
1694 if !bytes.Equal(asn1Issuer, asn1Subject) && len(parent.SubjectKeyId) > 0 {
1695 authorityKeyId = parent.SubjectKeyId
1698 subjectKeyId := template.SubjectKeyId
1699 if len(subjectKeyId) == 0 && template.IsCA {
1700 // SubjectKeyId generated using method 1 in RFC 5280, Section 4.2.1.2:
1701 // (1) The keyIdentifier is composed of the 160-bit SHA-1 hash of the
1702 // value of the BIT STRING subjectPublicKey (excluding the tag,
1703 // length, and number of unused bits).
1704 h := sha1.Sum(publicKeyBytes)
1708 // Check that the signer's public key matches the private key, if available.
1709 type privateKey interface {
1710 Equal(crypto.PublicKey) bool
1712 if privPub, ok := key.Public().(privateKey); !ok {
1713 return nil, errors.New("x509: internal error: supported public key does not implement Equal")
1714 } else if parent.PublicKey != nil && !privPub.Equal(parent.PublicKey) {
1715 return nil, errors.New("x509: provided PrivateKey doesn't match parent's PublicKey")
1718 extensions, err := buildCertExtensions(template, bytes.Equal(asn1Subject, emptyASN1Subject), authorityKeyId, subjectKeyId)
1723 encodedPublicKey := asn1.BitString{BitLength: len(publicKeyBytes) * 8, Bytes: publicKeyBytes}
1724 c := tbsCertificate{
1726 SerialNumber: template.SerialNumber,
1727 SignatureAlgorithm: signatureAlgorithm,
1728 Issuer: asn1.RawValue{FullBytes: asn1Issuer},
1729 Validity: validity{template.NotBefore.UTC(), template.NotAfter.UTC()},
1730 Subject: asn1.RawValue{FullBytes: asn1Subject},
1731 PublicKey: publicKeyInfo{nil, publicKeyAlgorithm, encodedPublicKey},
1732 Extensions: extensions,
1735 tbsCertContents, err := asn1.Marshal(c)
1739 c.Raw = tbsCertContents
1741 signed := tbsCertContents
1748 var signerOpts crypto.SignerOpts = hashFunc
1749 if template.SignatureAlgorithm != 0 && template.SignatureAlgorithm.isRSAPSS() {
1750 signerOpts = &rsa.PSSOptions{
1751 SaltLength: rsa.PSSSaltLengthEqualsHash,
1756 var signature []byte
1757 signature, err = key.Sign(rand, signed, signerOpts)
1762 signedCert, err := asn1.Marshal(certificate{
1765 asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
1771 // Check the signature to ensure the crypto.Signer behaved correctly.
1772 if err := checkSignature(getSignatureAlgorithmFromAI(signatureAlgorithm), c.Raw, signature, key.Public(), true); err != nil {
1773 return nil, fmt.Errorf("x509: signature over certificate returned by signer is invalid: %w", err)
1776 return signedCert, nil
1779 // pemCRLPrefix is the magic string that indicates that we have a PEM encoded
1781 var pemCRLPrefix = []byte("-----BEGIN X509 CRL")
1783 // pemType is the type of a PEM encoded CRL.
1784 var pemType = "X509 CRL"
1786 // ParseCRL parses a CRL from the given bytes. It's often the case that PEM
1787 // encoded CRLs will appear where they should be DER encoded, so this function
1788 // will transparently handle PEM encoding as long as there isn't any leading
1791 // Deprecated: Use ParseRevocationList instead.
1792 func ParseCRL(crlBytes []byte) (*pkix.CertificateList, error) {
1793 if bytes.HasPrefix(crlBytes, pemCRLPrefix) {
1794 block, _ := pem.Decode(crlBytes)
1795 if block != nil && block.Type == pemType {
1796 crlBytes = block.Bytes
1799 return ParseDERCRL(crlBytes)
1802 // ParseDERCRL parses a DER encoded CRL from the given bytes.
1804 // Deprecated: Use ParseRevocationList instead.
1805 func ParseDERCRL(derBytes []byte) (*pkix.CertificateList, error) {
1806 certList := new(pkix.CertificateList)
1807 if rest, err := asn1.Unmarshal(derBytes, certList); err != nil {
1809 } else if len(rest) != 0 {
1810 return nil, errors.New("x509: trailing data after CRL")
1812 return certList, nil
1815 // CreateCRL returns a DER encoded CRL, signed by this Certificate, that
1816 // contains the given list of revoked certificates.
1818 // Deprecated: this method does not generate an RFC 5280 conformant X.509 v2 CRL.
1819 // To generate a standards compliant CRL, use CreateRevocationList instead.
1820 func (c *Certificate) CreateCRL(rand io.Reader, priv any, revokedCerts []pkix.RevokedCertificate, now, expiry time.Time) (crlBytes []byte, err error) {
1821 key, ok := priv.(crypto.Signer)
1823 return nil, errors.New("x509: certificate private key does not implement crypto.Signer")
1826 hashFunc, signatureAlgorithm, err := signingParamsForPublicKey(key.Public(), 0)
1831 // Force revocation times to UTC per RFC 5280.
1832 revokedCertsUTC := make([]pkix.RevokedCertificate, len(revokedCerts))
1833 for i, rc := range revokedCerts {
1834 rc.RevocationTime = rc.RevocationTime.UTC()
1835 revokedCertsUTC[i] = rc
1838 tbsCertList := pkix.TBSCertificateList{
1840 Signature: signatureAlgorithm,
1841 Issuer: c.Subject.ToRDNSequence(),
1842 ThisUpdate: now.UTC(),
1843 NextUpdate: expiry.UTC(),
1844 RevokedCertificates: revokedCertsUTC,
1848 if len(c.SubjectKeyId) > 0 {
1849 var aki pkix.Extension
1850 aki.Id = oidExtensionAuthorityKeyId
1851 aki.Value, err = asn1.Marshal(authKeyId{Id: c.SubjectKeyId})
1855 tbsCertList.Extensions = append(tbsCertList.Extensions, aki)
1858 tbsCertListContents, err := asn1.Marshal(tbsCertList)
1863 signed := tbsCertListContents
1870 var signature []byte
1871 signature, err = key.Sign(rand, signed, hashFunc)
1876 return asn1.Marshal(pkix.CertificateList{
1877 TBSCertList: tbsCertList,
1878 SignatureAlgorithm: signatureAlgorithm,
1879 SignatureValue: asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
1883 // CertificateRequest represents a PKCS #10, certificate signature request.
1884 type CertificateRequest struct {
1885 Raw []byte // Complete ASN.1 DER content (CSR, signature algorithm and signature).
1886 RawTBSCertificateRequest []byte // Certificate request info part of raw ASN.1 DER content.
1887 RawSubjectPublicKeyInfo []byte // DER encoded SubjectPublicKeyInfo.
1888 RawSubject []byte // DER encoded Subject.
1892 SignatureAlgorithm SignatureAlgorithm
1894 PublicKeyAlgorithm PublicKeyAlgorithm
1899 // Attributes contains the CSR attributes that can parse as
1900 // pkix.AttributeTypeAndValueSET.
1902 // Deprecated: Use Extensions and ExtraExtensions instead for parsing and
1903 // generating the requestedExtensions attribute.
1904 Attributes []pkix.AttributeTypeAndValueSET
1906 // Extensions contains all requested extensions, in raw form. When parsing
1907 // CSRs, this can be used to extract extensions that are not parsed by this
1909 Extensions []pkix.Extension
1911 // ExtraExtensions contains extensions to be copied, raw, into any CSR
1912 // marshaled by CreateCertificateRequest. Values override any extensions
1913 // that would otherwise be produced based on the other fields but are
1914 // overridden by any extensions specified in Attributes.
1916 // The ExtraExtensions field is not populated by ParseCertificateRequest,
1917 // see Extensions instead.
1918 ExtraExtensions []pkix.Extension
1920 // Subject Alternate Name values.
1922 EmailAddresses []string
1923 IPAddresses []net.IP
1927 // These structures reflect the ASN.1 structure of X.509 certificate
1928 // signature requests (see RFC 2986):
1930 type tbsCertificateRequest struct {
1933 Subject asn1.RawValue
1934 PublicKey publicKeyInfo
1935 RawAttributes []asn1.RawValue `asn1:"tag:0"`
1938 type certificateRequest struct {
1940 TBSCSR tbsCertificateRequest
1941 SignatureAlgorithm pkix.AlgorithmIdentifier
1942 SignatureValue asn1.BitString
1945 // oidExtensionRequest is a PKCS #9 OBJECT IDENTIFIER that indicates requested
1946 // extensions in a CSR.
1947 var oidExtensionRequest = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 14}
1949 // newRawAttributes converts AttributeTypeAndValueSETs from a template
1950 // CertificateRequest's Attributes into tbsCertificateRequest RawAttributes.
1951 func newRawAttributes(attributes []pkix.AttributeTypeAndValueSET) ([]asn1.RawValue, error) {
1952 var rawAttributes []asn1.RawValue
1953 b, err := asn1.Marshal(attributes)
1957 rest, err := asn1.Unmarshal(b, &rawAttributes)
1962 return nil, errors.New("x509: failed to unmarshal raw CSR Attributes")
1964 return rawAttributes, nil
1967 // parseRawAttributes Unmarshals RawAttributes into AttributeTypeAndValueSETs.
1968 func parseRawAttributes(rawAttributes []asn1.RawValue) []pkix.AttributeTypeAndValueSET {
1969 var attributes []pkix.AttributeTypeAndValueSET
1970 for _, rawAttr := range rawAttributes {
1971 var attr pkix.AttributeTypeAndValueSET
1972 rest, err := asn1.Unmarshal(rawAttr.FullBytes, &attr)
1973 // Ignore attributes that don't parse into pkix.AttributeTypeAndValueSET
1974 // (i.e.: challengePassword or unstructuredName).
1975 if err == nil && len(rest) == 0 {
1976 attributes = append(attributes, attr)
1982 // parseCSRExtensions parses the attributes from a CSR and extracts any
1983 // requested extensions.
1984 func parseCSRExtensions(rawAttributes []asn1.RawValue) ([]pkix.Extension, error) {
1985 // pkcs10Attribute reflects the Attribute structure from RFC 2986, Section 4.1.
1986 type pkcs10Attribute struct {
1987 Id asn1.ObjectIdentifier
1988 Values []asn1.RawValue `asn1:"set"`
1991 var ret []pkix.Extension
1992 requestedExts := make(map[string]bool)
1993 for _, rawAttr := range rawAttributes {
1994 var attr pkcs10Attribute
1995 if rest, err := asn1.Unmarshal(rawAttr.FullBytes, &attr); err != nil || len(rest) != 0 || len(attr.Values) == 0 {
1996 // Ignore attributes that don't parse.
2000 if !attr.Id.Equal(oidExtensionRequest) {
2004 var extensions []pkix.Extension
2005 if _, err := asn1.Unmarshal(attr.Values[0].FullBytes, &extensions); err != nil {
2008 for _, ext := range extensions {
2009 oidStr := ext.Id.String()
2010 if requestedExts[oidStr] {
2011 return nil, errors.New("x509: certificate request contains duplicate requested extensions")
2013 requestedExts[oidStr] = true
2015 ret = append(ret, extensions...)
2021 // CreateCertificateRequest creates a new certificate request based on a
2022 // template. The following members of template are used:
2024 // - SignatureAlgorithm
2030 // - ExtraExtensions
2031 // - Attributes (deprecated)
2033 // priv is the private key to sign the CSR with, and the corresponding public
2034 // key will be included in the CSR. It must implement crypto.Signer and its
2035 // Public() method must return a *rsa.PublicKey or a *ecdsa.PublicKey or a
2036 // ed25519.PublicKey. (A *rsa.PrivateKey, *ecdsa.PrivateKey or
2037 // ed25519.PrivateKey satisfies this.)
2039 // The returned slice is the certificate request in DER encoding.
2040 func CreateCertificateRequest(rand io.Reader, template *CertificateRequest, priv any) (csr []byte, err error) {
2041 key, ok := priv.(crypto.Signer)
2043 return nil, errors.New("x509: certificate private key does not implement crypto.Signer")
2046 var hashFunc crypto.Hash
2047 var sigAlgo pkix.AlgorithmIdentifier
2048 hashFunc, sigAlgo, err = signingParamsForPublicKey(key.Public(), template.SignatureAlgorithm)
2053 var publicKeyBytes []byte
2054 var publicKeyAlgorithm pkix.AlgorithmIdentifier
2055 publicKeyBytes, publicKeyAlgorithm, err = marshalPublicKey(key.Public())
2060 extensions, err := buildCSRExtensions(template)
2065 // Make a copy of template.Attributes because we may alter it below.
2066 attributes := make([]pkix.AttributeTypeAndValueSET, 0, len(template.Attributes))
2067 for _, attr := range template.Attributes {
2068 values := make([][]pkix.AttributeTypeAndValue, len(attr.Value))
2069 copy(values, attr.Value)
2070 attributes = append(attributes, pkix.AttributeTypeAndValueSET{
2076 extensionsAppended := false
2077 if len(extensions) > 0 {
2078 // Append the extensions to an existing attribute if possible.
2079 for _, atvSet := range attributes {
2080 if !atvSet.Type.Equal(oidExtensionRequest) || len(atvSet.Value) == 0 {
2084 // specifiedExtensions contains all the extensions that we
2085 // found specified via template.Attributes.
2086 specifiedExtensions := make(map[string]bool)
2088 for _, atvs := range atvSet.Value {
2089 for _, atv := range atvs {
2090 specifiedExtensions[atv.Type.String()] = true
2094 newValue := make([]pkix.AttributeTypeAndValue, 0, len(atvSet.Value[0])+len(extensions))
2095 newValue = append(newValue, atvSet.Value[0]...)
2097 for _, e := range extensions {
2098 if specifiedExtensions[e.Id.String()] {
2099 // Attributes already contained a value for
2100 // this extension and it takes priority.
2104 newValue = append(newValue, pkix.AttributeTypeAndValue{
2105 // There is no place for the critical
2106 // flag in an AttributeTypeAndValue.
2112 atvSet.Value[0] = newValue
2113 extensionsAppended = true
2118 rawAttributes, err := newRawAttributes(attributes)
2123 // If not included in attributes, add a new attribute for the
2125 if len(extensions) > 0 && !extensionsAppended {
2127 Type asn1.ObjectIdentifier
2128 Value [][]pkix.Extension `asn1:"set"`
2130 Type: oidExtensionRequest,
2131 Value: [][]pkix.Extension{extensions},
2134 b, err := asn1.Marshal(attr)
2136 return nil, errors.New("x509: failed to serialise extensions attribute: " + err.Error())
2139 var rawValue asn1.RawValue
2140 if _, err := asn1.Unmarshal(b, &rawValue); err != nil {
2144 rawAttributes = append(rawAttributes, rawValue)
2147 asn1Subject := template.RawSubject
2148 if len(asn1Subject) == 0 {
2149 asn1Subject, err = asn1.Marshal(template.Subject.ToRDNSequence())
2155 tbsCSR := tbsCertificateRequest{
2156 Version: 0, // PKCS #10, RFC 2986
2157 Subject: asn1.RawValue{FullBytes: asn1Subject},
2158 PublicKey: publicKeyInfo{
2159 Algorithm: publicKeyAlgorithm,
2160 PublicKey: asn1.BitString{
2161 Bytes: publicKeyBytes,
2162 BitLength: len(publicKeyBytes) * 8,
2165 RawAttributes: rawAttributes,
2168 tbsCSRContents, err := asn1.Marshal(tbsCSR)
2172 tbsCSR.Raw = tbsCSRContents
2174 signed := tbsCSRContents
2181 var signature []byte
2182 signature, err = key.Sign(rand, signed, hashFunc)
2187 return asn1.Marshal(certificateRequest{
2189 SignatureAlgorithm: sigAlgo,
2190 SignatureValue: asn1.BitString{
2192 BitLength: len(signature) * 8,
2197 // ParseCertificateRequest parses a single certificate request from the
2198 // given ASN.1 DER data.
2199 func ParseCertificateRequest(asn1Data []byte) (*CertificateRequest, error) {
2200 var csr certificateRequest
2202 rest, err := asn1.Unmarshal(asn1Data, &csr)
2205 } else if len(rest) != 0 {
2206 return nil, asn1.SyntaxError{Msg: "trailing data"}
2209 return parseCertificateRequest(&csr)
2212 func parseCertificateRequest(in *certificateRequest) (*CertificateRequest, error) {
2213 out := &CertificateRequest{
2215 RawTBSCertificateRequest: in.TBSCSR.Raw,
2216 RawSubjectPublicKeyInfo: in.TBSCSR.PublicKey.Raw,
2217 RawSubject: in.TBSCSR.Subject.FullBytes,
2219 Signature: in.SignatureValue.RightAlign(),
2220 SignatureAlgorithm: getSignatureAlgorithmFromAI(in.SignatureAlgorithm),
2222 PublicKeyAlgorithm: getPublicKeyAlgorithmFromOID(in.TBSCSR.PublicKey.Algorithm.Algorithm),
2224 Version: in.TBSCSR.Version,
2225 Attributes: parseRawAttributes(in.TBSCSR.RawAttributes),
2229 if out.PublicKeyAlgorithm != UnknownPublicKeyAlgorithm {
2230 out.PublicKey, err = parsePublicKey(&in.TBSCSR.PublicKey)
2236 var subject pkix.RDNSequence
2237 if rest, err := asn1.Unmarshal(in.TBSCSR.Subject.FullBytes, &subject); err != nil {
2239 } else if len(rest) != 0 {
2240 return nil, errors.New("x509: trailing data after X.509 Subject")
2243 out.Subject.FillFromRDNSequence(&subject)
2245 if out.Extensions, err = parseCSRExtensions(in.TBSCSR.RawAttributes); err != nil {
2249 for _, extension := range out.Extensions {
2251 case extension.Id.Equal(oidExtensionSubjectAltName):
2252 out.DNSNames, out.EmailAddresses, out.IPAddresses, out.URIs, err = parseSANExtension(extension.Value)
2262 // CheckSignature reports whether the signature on c is valid.
2263 func (c *CertificateRequest) CheckSignature() error {
2264 return checkSignature(c.SignatureAlgorithm, c.RawTBSCertificateRequest, c.Signature, c.PublicKey, true)
2267 // RevocationList contains the fields used to create an X.509 v2 Certificate
2268 // Revocation list with CreateRevocationList.
2269 type RevocationList struct {
2270 // Raw contains the complete ASN.1 DER content of the CRL (tbsCertList,
2271 // signatureAlgorithm, and signatureValue.)
2273 // RawTBSRevocationList contains just the tbsCertList portion of the ASN.1
2275 RawTBSRevocationList []byte
2276 // RawIssuer contains the DER encoded Issuer.
2279 // Issuer contains the DN of the issuing certificate.
2281 // AuthorityKeyId is used to identify the public key associated with the
2282 // issuing certificate. It is populated from the authorityKeyIdentifier
2283 // extension when parsing a CRL. It is ignored when creating a CRL; the
2284 // extension is populated from the issuing certificate itself.
2285 AuthorityKeyId []byte
2288 // SignatureAlgorithm is used to determine the signature algorithm to be
2289 // used when signing the CRL. If 0 the default algorithm for the signing
2290 // key will be used.
2291 SignatureAlgorithm SignatureAlgorithm
2293 // RevokedCertificates is used to populate the revokedCertificates
2294 // sequence in the CRL, it may be empty. RevokedCertificates may be nil,
2295 // in which case an empty CRL will be created.
2296 RevokedCertificates []pkix.RevokedCertificate
2298 // Number is used to populate the X.509 v2 cRLNumber extension in the CRL,
2299 // which should be a monotonically increasing sequence number for a given
2300 // CRL scope and CRL issuer. It is also populated from the cRLNumber
2301 // extension when parsing a CRL.
2304 // ThisUpdate is used to populate the thisUpdate field in the CRL, which
2305 // indicates the issuance date of the CRL.
2306 ThisUpdate time.Time
2307 // NextUpdate is used to populate the nextUpdate field in the CRL, which
2308 // indicates the date by which the next CRL will be issued. NextUpdate
2309 // must be greater than ThisUpdate.
2310 NextUpdate time.Time
2312 // Extensions contains raw X.509 extensions. When creating a CRL,
2313 // the Extensions field is ignored, see ExtraExtensions.
2314 Extensions []pkix.Extension
2316 // ExtraExtensions contains any additional extensions to add directly to
2318 ExtraExtensions []pkix.Extension
2321 // These structures reflect the ASN.1 structure of X.509 CRLs better than
2322 // the existing crypto/x509/pkix variants do. These mirror the existing
2323 // certificate structs in this file.
2325 // Notably, we include issuer as an asn1.RawValue, mirroring the behavior of
2326 // tbsCertificate and allowing raw (unparsed) subjects to be passed cleanly.
2327 type certificateList struct {
2328 TBSCertList tbsCertificateList
2329 SignatureAlgorithm pkix.AlgorithmIdentifier
2330 SignatureValue asn1.BitString
2333 type tbsCertificateList struct {
2335 Version int `asn1:"optional,default:0"`
2336 Signature pkix.AlgorithmIdentifier
2337 Issuer asn1.RawValue
2338 ThisUpdate time.Time
2339 NextUpdate time.Time `asn1:"optional"`
2340 RevokedCertificates []pkix.RevokedCertificate `asn1:"optional"`
2341 Extensions []pkix.Extension `asn1:"tag:0,optional,explicit"`
2344 // CreateRevocationList creates a new X.509 v2 Certificate Revocation List,
2345 // according to RFC 5280, based on template.
2347 // The CRL is signed by priv which should be the private key associated with
2348 // the public key in the issuer certificate.
2350 // The issuer may not be nil, and the crlSign bit must be set in KeyUsage in
2351 // order to use it as a CRL issuer.
2353 // The issuer distinguished name CRL field and authority key identifier
2354 // extension are populated using the issuer certificate. issuer must have
2355 // SubjectKeyId set.
2356 func CreateRevocationList(rand io.Reader, template *RevocationList, issuer *Certificate, priv crypto.Signer) ([]byte, error) {
2357 if template == nil {
2358 return nil, errors.New("x509: template can not be nil")
2361 return nil, errors.New("x509: issuer can not be nil")
2363 if (issuer.KeyUsage & KeyUsageCRLSign) == 0 {
2364 return nil, errors.New("x509: issuer must have the crlSign key usage bit set")
2366 if len(issuer.SubjectKeyId) == 0 {
2367 return nil, errors.New("x509: issuer certificate doesn't contain a subject key identifier")
2369 if template.NextUpdate.Before(template.ThisUpdate) {
2370 return nil, errors.New("x509: template.ThisUpdate is after template.NextUpdate")
2372 if template.Number == nil {
2373 return nil, errors.New("x509: template contains nil Number field")
2376 hashFunc, signatureAlgorithm, err := signingParamsForPublicKey(priv.Public(), template.SignatureAlgorithm)
2381 // Force revocation times to UTC per RFC 5280.
2382 revokedCertsUTC := make([]pkix.RevokedCertificate, len(template.RevokedCertificates))
2383 for i, rc := range template.RevokedCertificates {
2384 rc.RevocationTime = rc.RevocationTime.UTC()
2385 revokedCertsUTC[i] = rc
2388 aki, err := asn1.Marshal(authKeyId{Id: issuer.SubjectKeyId})
2393 if numBytes := template.Number.Bytes(); len(numBytes) > 20 || (len(numBytes) == 20 && numBytes[0]&0x80 != 0) {
2394 return nil, errors.New("x509: CRL number exceeds 20 octets")
2396 crlNum, err := asn1.Marshal(template.Number)
2401 // Correctly use the issuer's subject sequence if one is specified.
2402 issuerSubject, err := subjectBytes(issuer)
2407 tbsCertList := tbsCertificateList{
2409 Signature: signatureAlgorithm,
2410 Issuer: asn1.RawValue{FullBytes: issuerSubject},
2411 ThisUpdate: template.ThisUpdate.UTC(),
2412 NextUpdate: template.NextUpdate.UTC(),
2413 Extensions: []pkix.Extension{
2415 Id: oidExtensionAuthorityKeyId,
2419 Id: oidExtensionCRLNumber,
2424 if len(revokedCertsUTC) > 0 {
2425 tbsCertList.RevokedCertificates = revokedCertsUTC
2428 if len(template.ExtraExtensions) > 0 {
2429 tbsCertList.Extensions = append(tbsCertList.Extensions, template.ExtraExtensions...)
2432 tbsCertListContents, err := asn1.Marshal(tbsCertList)
2437 // Optimization to only marshal this struct once, when signing and
2438 // then embedding in certificateList below.
2439 tbsCertList.Raw = tbsCertListContents
2441 input := tbsCertListContents
2444 h.Write(tbsCertListContents)
2447 var signerOpts crypto.SignerOpts = hashFunc
2448 if template.SignatureAlgorithm.isRSAPSS() {
2449 signerOpts = &rsa.PSSOptions{
2450 SaltLength: rsa.PSSSaltLengthEqualsHash,
2455 signature, err := priv.Sign(rand, input, signerOpts)
2460 return asn1.Marshal(certificateList{
2461 TBSCertList: tbsCertList,
2462 SignatureAlgorithm: signatureAlgorithm,
2463 SignatureValue: asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
2467 // CheckSignatureFrom verifies that the signature on rl is a valid signature
2469 func (rl *RevocationList) CheckSignatureFrom(parent *Certificate) error {
2470 if parent.Version == 3 && !parent.BasicConstraintsValid ||
2471 parent.BasicConstraintsValid && !parent.IsCA {
2472 return ConstraintViolationError{}
2475 if parent.KeyUsage != 0 && parent.KeyUsage&KeyUsageCRLSign == 0 {
2476 return ConstraintViolationError{}
2479 if parent.PublicKeyAlgorithm == UnknownPublicKeyAlgorithm {
2480 return ErrUnsupportedAlgorithm
2483 return parent.CheckSignature(rl.SignatureAlgorithm, rl.RawTBSRevocationList, rl.Signature)