diff options
Diffstat (limited to 'src/crypto/x509/x509.go')
| -rw-r--r-- | src/crypto/x509/x509.go | 2276 |
1 files changed, 2276 insertions, 0 deletions
diff --git a/src/crypto/x509/x509.go b/src/crypto/x509/x509.go new file mode 100644 index 0000000..6cd51e5 --- /dev/null +++ b/src/crypto/x509/x509.go @@ -0,0 +1,2276 @@ +// 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 parses X.509-encoded keys and certificates. +package x509 + +import ( + "bytes" + "crypto" + "crypto/ecdsa" + "crypto/ed25519" + "crypto/elliptic" + "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, or +// ed25519.PublicKey. 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") + } + algo := getPublicKeyAlgorithmFromOID(pki.Algorithm.Algorithm) + if algo == UnknownPublicKeyAlgorithm { + return nil, errors.New("x509: unknown public key algorithm") + } + return parsePublicKey(algo, &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 + 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 +// and ed25519.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 { + Raw asn1.RawContent + 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 { + switch algo { + case SHA256WithRSAPSS, SHA384WithRSAPSS, SHA512WithRSAPSS: + return true + default: + return false + } +} + +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 // Unsupported. + 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 +// +// md2WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 2 } +// +// 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 ( + oidSignatureMD2WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 2} + 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 + pubKeyAlgo PublicKeyAlgorithm + hash crypto.Hash +}{ + {MD2WithRSA, "MD2-RSA", oidSignatureMD2WithRSA, RSA, crypto.Hash(0) /* no value for MD2 */}, + {MD5WithRSA, "MD5-RSA", oidSignatureMD5WithRSA, RSA, crypto.MD5}, + {SHA1WithRSA, "SHA1-RSA", oidSignatureSHA1WithRSA, RSA, crypto.SHA1}, + {SHA1WithRSA, "SHA1-RSA", oidISOSignatureSHA1WithRSA, RSA, crypto.SHA1}, + {SHA256WithRSA, "SHA256-RSA", oidSignatureSHA256WithRSA, RSA, crypto.SHA256}, + {SHA384WithRSA, "SHA384-RSA", oidSignatureSHA384WithRSA, RSA, crypto.SHA384}, + {SHA512WithRSA, "SHA512-RSA", oidSignatureSHA512WithRSA, RSA, crypto.SHA512}, + {SHA256WithRSAPSS, "SHA256-RSAPSS", oidSignatureRSAPSS, RSA, crypto.SHA256}, + {SHA384WithRSAPSS, "SHA384-RSAPSS", oidSignatureRSAPSS, RSA, crypto.SHA384}, + {SHA512WithRSAPSS, "SHA512-RSAPSS", oidSignatureRSAPSS, RSA, crypto.SHA512}, + {DSAWithSHA1, "DSA-SHA1", oidSignatureDSAWithSHA1, DSA, crypto.SHA1}, + {DSAWithSHA256, "DSA-SHA256", oidSignatureDSAWithSHA256, DSA, crypto.SHA256}, + {ECDSAWithSHA1, "ECDSA-SHA1", oidSignatureECDSAWithSHA1, ECDSA, crypto.SHA1}, + {ECDSAWithSHA256, "ECDSA-SHA256", oidSignatureECDSAWithSHA256, ECDSA, crypto.SHA256}, + {ECDSAWithSHA384, "ECDSA-SHA384", oidSignatureECDSAWithSHA384, ECDSA, crypto.SHA384}, + {ECDSAWithSHA512, "ECDSA-SHA512", oidSignatureECDSAWithSHA512, ECDSA, crypto.SHA512}, + {PureEd25519, "Ed25519", oidSignatureEd25519, Ed25519, crypto.Hash(0) /* no pre-hashing */}, +} + +// hashToPSSParameters contains the 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 hashToPSSParameters = map[crypto.Hash]asn1.RawValue{ + 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}}, + 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}}, + 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}}, +} + +// 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 +} + +// 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 } +// +// 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 } +var ( + oidPublicKeyRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1} + oidPublicKeyDSA = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 1} + oidPublicKeyECDSA = asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1} + oidPublicKeyEd25519 = oidSignatureEd25519 +) + +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 +} + +// 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 []asn1.ObjectIdentifier +} + +// 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. +// +// To temporarily restore support for SHA-1 signatures, include the value +// "x509sha1=1" in the GODEBUG environment variable. Note that this option will +// be removed in a future release. +type InsecureAlgorithmError SignatureAlgorithm + +func (e InsecureAlgorithmError) Error() string { + var override string + if SignatureAlgorithm(e) == SHA1WithRSA || SignatureAlgorithm(e) == ECDSAWithSHA1 { + override = " (temporarily override with GODEBUG=x509sha1=1)" + } + return fmt.Sprintf("x509: cannot verify signature: insecure algorithm %v", SignatureAlgorithm(e)) + override +} + +// 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. SHA1WithRSA and ECDSAWithSHA1 signatures are not supported. +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 + } + + // TODO(agl): don't ignore the path length constraint. + + 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. +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 + } + } + + switch hashType { + case crypto.Hash(0): + if pubKeyAlgo != Ed25519 { + return ErrUnsupportedAlgorithm + } + case crypto.MD5: + return InsecureAlgorithmError(algo) + case crypto.SHA1: + // SHA-1 signatures are mostly disabled. See go.dev/issue/41682. + if !allowSHA1 && godebug.Get("x509sha1") != "1" { + 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} +) + +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} +) + +// oidNotInExtensions 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 +} + +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++ + } + + if len(template.PolicyIdentifiers) > 0 && + !oidInExtensions(oidExtensionCertificatePolicies, template.ExtraExtensions) { + ret[n], err = marshalCertificatePolicies(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(policyIdentifiers []asn1.ObjectIdentifier) (pkix.Extension, error) { + ext := pkix.Extension{Id: oidExtensionCertificatePolicies} + policies := make([]policyInformation, len(policyIdentifiers)) + for i, policy := range policyIdentifiers { + policies[i].Policy = policy + } + var err error + ext.Value, err = asn1.Marshal(policies) + 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()) +} + +// signingParamsForPublicKey returns the parameters to use for signing with +// priv. If requestedSigAlgo is not zero then it overrides the default +// signature algorithm. +func signingParamsForPublicKey(pub any, requestedSigAlgo SignatureAlgorithm) (hashFunc crypto.Hash, sigAlgo pkix.AlgorithmIdentifier, err error) { + var pubType PublicKeyAlgorithm + + switch pub := pub.(type) { + case *rsa.PublicKey: + pubType = RSA + hashFunc = crypto.SHA256 + sigAlgo.Algorithm = oidSignatureSHA256WithRSA + sigAlgo.Parameters = asn1.NullRawValue + + case *ecdsa.PublicKey: + pubType = ECDSA + + switch pub.Curve { + case elliptic.P224(), elliptic.P256(): + hashFunc = crypto.SHA256 + sigAlgo.Algorithm = oidSignatureECDSAWithSHA256 + case elliptic.P384(): + hashFunc = crypto.SHA384 + sigAlgo.Algorithm = oidSignatureECDSAWithSHA384 + case elliptic.P521(): + hashFunc = crypto.SHA512 + sigAlgo.Algorithm = oidSignatureECDSAWithSHA512 + default: + err = errors.New("x509: unknown elliptic curve") + } + + case ed25519.PublicKey: + pubType = Ed25519 + sigAlgo.Algorithm = oidSignatureEd25519 + + default: + err = errors.New("x509: only RSA, ECDSA and Ed25519 keys supported") + } + + if err != nil { + return + } + + if requestedSigAlgo == 0 { + return + } + + found := false + for _, details := range signatureAlgorithmDetails { + if details.algo == requestedSigAlgo { + if details.pubKeyAlgo != pubType { + err = errors.New("x509: requested SignatureAlgorithm does not match private key type") + return + } + sigAlgo.Algorithm, hashFunc = details.oid, details.hash + if hashFunc == 0 && pubType != Ed25519 { + err = errors.New("x509: cannot sign with hash function requested") + return + } + if hashFunc == crypto.MD5 { + err = errors.New("x509: signing with MD5 is not supported") + return + } + if requestedSigAlgo.isRSAPSS() { + sigAlgo.Parameters = hashToPSSParameters[hashFunc] + } + found = true + break + } + } + + if !found { + err = errors.New("x509: unknown SignatureAlgorithm") + } + + return +} + +// 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 +// - 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. +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") + } + + if template.SerialNumber == nil { + return nil, errors.New("x509: no SerialNumber given") + } + + // RFC 5280 Section 4.1.2.2: serial number must 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 template.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") + } + + hashFunc, signatureAlgorithm, err := signingParamsForPublicKey(key.Public(), template.SignatureAlgorithm) + if err != nil { + return nil, err + } + + publicKeyBytes, publicKeyAlgorithm, err := marshalPublicKey(pub) + if err != nil { + return nil, err + } + + 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: template.SerialNumber, + SignatureAlgorithm: signatureAlgorithm, + 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 + + signed := tbsCertContents + if hashFunc != 0 { + h := hashFunc.New() + h.Write(signed) + signed = h.Sum(nil) + } + + var signerOpts crypto.SignerOpts = hashFunc + if template.SignatureAlgorithm != 0 && template.SignatureAlgorithm.isRSAPSS() { + signerOpts = &rsa.PSSOptions{ + SaltLength: rsa.PSSSaltLengthEqualsHash, + Hash: hashFunc, + } + } + + var signature []byte + signature, err = key.Sign(rand, signed, signerOpts) + if err != nil { + return nil, err + } + + signedCert, err := asn1.Marshal(certificate{ + nil, + c, + signatureAlgorithm, + asn1.BitString{Bytes: signature, BitLength: len(signature) * 8}, + }) + if err != nil { + return nil, err + } + + // Check the signature to ensure the crypto.Signer behaved correctly. + if err := checkSignature(getSignatureAlgorithmFromAI(signatureAlgorithm), c.Raw, signature, key.Public(), true); err != nil { + return nil, fmt.Errorf("x509: signature over certificate returned by signer is invalid: %w", err) + } + + return signedCert, nil +} + +// 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") + } + + hashFunc, signatureAlgorithm, err := signingParamsForPublicKey(key.Public(), 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: signatureAlgorithm, + 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 + } + tbsCertList.Extensions = append(tbsCertList.Extensions, aki) + } + + tbsCertListContents, err := asn1.Marshal(tbsCertList) + if err != nil { + return + } + + signed := tbsCertListContents + if hashFunc != 0 { + h := hashFunc.New() + h.Write(signed) + signed = h.Sum(nil) + } + + var signature []byte + signature, err = key.Sign(rand, signed, hashFunc) + if err != nil { + return + } + + return asn1.Marshal(pkix.CertificateList{ + TBSCertList: tbsCertList, + SignatureAlgorithm: signatureAlgorithm, + 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") + } + + var hashFunc crypto.Hash + var sigAlgo pkix.AlgorithmIdentifier + hashFunc, sigAlgo, err = signingParamsForPublicKey(key.Public(), 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 + } + + // 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 + } + tbsCSR.Raw = tbsCSRContents + + signed := tbsCSRContents + if hashFunc != 0 { + h := hashFunc.New() + h.Write(signed) + signed = h.Sum(nil) + } + + var signature []byte + signature, err = key.Sign(rand, signed, hashFunc) + if err != nil { + return + } + + return asn1.Marshal(certificateRequest{ + TBSCSR: tbsCSR, + SignatureAlgorithm: sigAlgo, + 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 + out.PublicKey, err = parsePublicKey(out.PublicKeyAlgorithm, &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) +} + +// RevocationList contains the fields used to create an X.509 v2 Certificate +// Revocation list with CreateRevocationList. +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 + + // RevokedCertificates is used to populate the revokedCertificates + // sequence in the CRL, it may be empty. RevokedCertificates may be nil, + // in which case an empty CRL will be created. + 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 +} + +// 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") + } + + hashFunc, signatureAlgorithm, err := signingParamsForPublicKey(priv.Public(), template.SignatureAlgorithm) + if err != nil { + return nil, err + } + + // Force revocation times to UTC per RFC 5280. + revokedCertsUTC := make([]pkix.RevokedCertificate, len(template.RevokedCertificates)) + for i, rc := range template.RevokedCertificates { + rc.RevocationTime = rc.RevocationTime.UTC() + revokedCertsUTC[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 + } + + tbsCertList := pkix.TBSCertificateList{ + Version: 1, // v2 + Signature: signatureAlgorithm, + Issuer: issuer.Subject.ToRDNSequence(), + ThisUpdate: template.ThisUpdate.UTC(), + NextUpdate: template.NextUpdate.UTC(), + Extensions: []pkix.Extension{ + { + Id: oidExtensionAuthorityKeyId, + Value: aki, + }, + { + Id: oidExtensionCRLNumber, + Value: crlNum, + }, + }, + } + if len(revokedCertsUTC) > 0 { + tbsCertList.RevokedCertificates = revokedCertsUTC + } + + if len(template.ExtraExtensions) > 0 { + tbsCertList.Extensions = append(tbsCertList.Extensions, template.ExtraExtensions...) + } + + tbsCertListContents, err := asn1.Marshal(tbsCertList) + if err != nil { + return nil, err + } + + input := tbsCertListContents + if hashFunc != 0 { + h := hashFunc.New() + h.Write(tbsCertListContents) + input = h.Sum(nil) + } + var signerOpts crypto.SignerOpts = hashFunc + if template.SignatureAlgorithm.isRSAPSS() { + signerOpts = &rsa.PSSOptions{ + SaltLength: rsa.PSSSaltLengthEqualsHash, + Hash: hashFunc, + } + } + + signature, err := priv.Sign(rand, input, signerOpts) + if err != nil { + return nil, err + } + + return asn1.Marshal(pkix.CertificateList{ + TBSCertList: tbsCertList, + SignatureAlgorithm: signatureAlgorithm, + 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) +} |