func parseCertificate(in *certificate) (*Certificate, error) {
out := new(Certificate)
out.Raw = in.Raw
out.RawTBSCertificate = in.TBSCertificate.Raw
out.RawSubjectPublicKeyInfo = in.TBSCertificate.PublicKey.Raw
out.RawSubject = in.TBSCertificate.Subject.FullBytes
out.RawIssuer = in.TBSCertificate.Issuer.FullBytes
out.Signature = in.SignatureValue.RightAlign()
out.SignatureAlgorithm =
getSignatureAlgorithmFromOID(in.TBSCertificate.SignatureAlgorithm.Algorithm)
out.PublicKeyAlgorithm =
getPublicKeyAlgorithmFromOID(in.TBSCertificate.PublicKey.Algorithm.Algorithm)
var err error
out.PublicKey, err = parsePublicKey(out.PublicKeyAlgorithm, &in.TBSCertificate.PublicKey)
if err != nil {
return nil, err
}
if in.TBSCertificate.SerialNumber.Sign() < 0 {
return nil, errors.New("negative serial number")
}
out.Version = in.TBSCertificate.Version + 1
out.SerialNumber = in.TBSCertificate.SerialNumber
var issuer, subject pkix.RDNSequence
if _, err := asn1.Unmarshal(in.TBSCertificate.Subject.FullBytes, &subject); err != nil {
return nil, err
}
if _, err := asn1.Unmarshal(in.TBSCertificate.Issuer.FullBytes, &issuer); err != nil {
return nil, err
}
out.Issuer.FillFromRDNSequence(&issuer)
out.Subject.FillFromRDNSequence(&subject)
out.NotBefore = in.TBSCertificate.Validity.NotBefore
out.NotAfter = in.TBSCertificate.Validity.NotAfter
for _, e := range in.TBSCertificate.Extensions {
if len(e.Id) == 4 && e.Id[0] == 2 && e.Id[1] == 5 && e.Id[2] == 29 {
switch e.Id[3] {
case 15:
// RFC 5280, 4.2.1.3
var usageBits asn1.BitString
_, err := asn1.Unmarshal(e.Value, &usageBits)
if err == nil {
var usage int
for i := 0; i < 9; i++ {
if usageBits.At(i) != 0 {
usage |= 1 << uint(i)
}
}
out.KeyUsage = KeyUsage(usage)
continue
}
case 19:
// RFC 5280, 4.2.1.9
var constraints basicConstraints
_, err := asn1.Unmarshal(e.Value, &constraints)
if err == nil {
out.BasicConstraintsValid = true
out.IsCA = constraints.IsCA
out.MaxPathLen = constraints.MaxPathLen
continue
}
case 17:
// RFC 5280, 4.2.1.6
// SubjectAltName ::= GeneralNames
//
// GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName
//
// GeneralName ::= CHOICE {
// otherName [0] OtherName,
// rfc822Name [1] IA5String,
// dNSName [2] IA5String,
// x400Address [3] ORAddress,
// directoryName [4] Name,
// ediPartyName [5] EDIPartyName,
// uniformResourceIdentifier [6] IA5String,
// iPAddress [7] OCTET STRING,
// registeredID [8] OBJECT IDENTIFIER }
var seq asn1.RawValue
_, err := asn1.Unmarshal(e.Value, &seq)
if err != nil {
return nil, err
}
if !seq.IsCompound || seq.Tag != 16 || seq.Class != 0 {
return nil, asn1.StructuralError{Msg: "bad SAN sequence"}
}
parsedName := false
rest := seq.Bytes
for len(rest) > 0 {
var v asn1.RawValue
rest, err = asn1.Unmarshal(rest, &v)
if err != nil {
return nil, err
}
switch v.Tag {
case 1:
out.EmailAddresses = append(out.EmailAddresses, string(v.Bytes))
parsedName = true
case 2:
out.DNSNames = append(out.DNSNames, string(v.Bytes))
parsedName = true
}
}
if parsedName {
continue
}
// If we didn't parse any of the names then we
// fall through to the critical check below.
case 30:
// RFC 5280, 4.2.1.10
// NameConstraints ::= SEQUENCE {
// permittedSubtrees [0] GeneralSubtrees OPTIONAL,
// excludedSubtrees [1] GeneralSubtrees OPTIONAL }
//
// GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree
//
// GeneralSubtree ::= SEQUENCE {
// base GeneralName,
// minimum [0] BaseDistance DEFAULT 0,
// maximum [1] BaseDistance OPTIONAL }
//
// BaseDistance ::= INTEGER (0..MAX)
var constraints nameConstraints
_, err := asn1.Unmarshal(e.Value, &constraints)
if err != nil {
return nil, err
}
if len(constraints.Excluded) > 0 && e.Critical {
return out, UnhandledCriticalExtension{}
}
for _, subtree := range constraints.Permitted {
if subtree.Min > 0 || subtree.Max > 0 || len(subtree.Name) == 0 {
if e.Critical {
return out, UnhandledCriticalExtension{}
}
continue
}
out.PermittedDNSDomains = append(out.PermittedDNSDomains, subtree.Name)
}
continue
case 35:
// RFC 5280, 4.2.1.1
var a authKeyId
_, err = asn1.Unmarshal(e.Value, &a)
if err != nil {
return nil, err
}
out.AuthorityKeyId = a.Id
continue
case 37:
// RFC 5280, 4.2.1.12. Extended Key Usage
// id-ce-extKeyUsage OBJECT IDENTIFIER ::= { id-ce 37 }
//
// ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
//
// KeyPurposeId ::= OBJECT IDENTIFIER
var keyUsage []asn1.ObjectIdentifier
_, err = asn1.Unmarshal(e.Value, &keyUsage)
if err != nil {
return nil, err
}
for _, u := range keyUsage {
switch {
case u.Equal(oidExtKeyUsageAny):
out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageAny)
case u.Equal(oidExtKeyUsageServerAuth):
out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageServerAuth)
case u.Equal(oidExtKeyUsageClientAuth):
out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageClientAuth)
case u.Equal(oidExtKeyUsageCodeSigning):
out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageCodeSigning)
case u.Equal(oidExtKeyUsageEmailProtection):
out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageEmailProtection)
case u.Equal(oidExtKeyUsageTimeStamping):
out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageTimeStamping)
case u.Equal(oidExtKeyUsageOCSPSigning):
out.ExtKeyUsage = append(out.ExtKeyUsage, ExtKeyUsageOCSPSigning)
default:
out.UnknownExtKeyUsage = append(out.UnknownExtKeyUsage, u)
}
}
continue
case 14:
// RFC 5280, 4.2.1.2
var keyid []byte
_, err = asn1.Unmarshal(e.Value, &keyid)
if err != nil {
return nil, err
}
out.SubjectKeyId = keyid
continue
case 32:
// RFC 5280 4.2.1.4: Certificate Policies
var policies []policyInformation
if _, err = asn1.Unmarshal(e.Value, &policies); err != nil {
return nil, err
}
out.PolicyIdentifiers = make([]asn1.ObjectIdentifier, len(policies))
for i, policy := range policies {
out.PolicyIdentifiers[i] = policy.Policy
}
}
}
if e.Critical {
return out, UnhandledCriticalExtension{}
}
}
return out, nil
}
func parseCertificate(in *certificate) (*Certificate, error) {
out := new(Certificate)
out.Raw = in.Raw
out.RawTBSCertificate = in.TBSCertificate.Raw
out.RawSubjectPublicKeyInfo = in.TBSCertificate.PublicKey.Raw
out.RawSubject = in.TBSCertificate.Subject.FullBytes
out.RawIssuer = in.TBSCertificate.Issuer.FullBytes
out.Signature = in.SignatureValue.RightAlign()
out.SignatureAlgorithm =
getSignatureAlgorithmFromOID(in.TBSCertificate.SignatureAlgorithm.Algorithm)
out.PublicKeyAlgorithm =
getPublicKeyAlgorithmFromOID(in.TBSCertificate.PublicKey.Algorithm.Algorithm)
var err error
out.PublicKey, err = parsePublicKey(out.PublicKeyAlgorithm, &in.TBSCertificate.PublicKey)
if err != nil {
return nil, err
}
if in.TBSCertificate.SerialNumber.Sign() < 0 {
return nil, errors.New("x509: negative serial number")
}
out.Version = in.TBSCertificate.Version + 1
out.SerialNumber = in.TBSCertificate.SerialNumber
var issuer, subject pkix.RDNSequence
if _, err := asn1.Unmarshal(in.TBSCertificate.Subject.FullBytes, &subject); err != nil {
return nil, err
}
if _, err := asn1.Unmarshal(in.TBSCertificate.Issuer.FullBytes, &issuer); err != nil {
return nil, err
}
out.Issuer.FillFromRDNSequence(&issuer)
out.Subject.FillFromRDNSequence(&subject)
out.NotBefore = in.TBSCertificate.Validity.NotBefore
out.NotAfter = in.TBSCertificate.Validity.NotAfter
for _, e := range in.TBSCertificate.Extensions {
out.Extensions = append(out.Extensions, e)
if len(e.Id) == 4 && e.Id[0] == 2 && e.Id[1] == 5 && e.Id[2] == 29 {
switch e.Id[3] {
case 15:
// RFC 5280, 4.2.1.3
var usageBits asn1.BitString
_, err := asn1.Unmarshal(e.Value, &usageBits)
if err == nil {
var usage int
for i := 0; i < 9; i++ {
if usageBits.At(i) != 0 {
usage |= 1 << uint(i)
}
}
out.KeyUsage = KeyUsage(usage)
continue
}
case 19:
// RFC 5280, 4.2.1.9
var constraints basicConstraints
_, err := asn1.Unmarshal(e.Value, &constraints)
if err == nil {
out.BasicConstraintsValid = true
out.IsCA = constraints.IsCA
out.MaxPathLen = constraints.MaxPathLen
continue
}
case 17:
// RFC 5280, 4.2.1.6
// SubjectAltName ::= GeneralNames
//
// GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName
//
// GeneralName ::= CHOICE {
// otherName [0] OtherName,
// rfc822Name [1] IA5String,
// dNSName [2] IA5String,
// x400Address [3] ORAddress,
// directoryName [4] Name,
// ediPartyName [5] EDIPartyName,
// uniformResourceIdentifier [6] IA5String,
// iPAddress [7] OCTET STRING,
// registeredID [8] OBJECT IDENTIFIER }
var seq asn1.RawValue
_, err := asn1.Unmarshal(e.Value, &seq)
if err != nil {
return nil, err
}
if !seq.IsCompound || seq.Tag != 16 || seq.Class != 0 {
return nil, asn1.StructuralError{Msg: "bad SAN sequence"}
}
parsedName := false
rest := seq.Bytes
for len(rest) > 0 {
var v asn1.RawValue
rest, err = asn1.Unmarshal(rest, &v)
if err != nil {
return nil, err
}
switch v.Tag {
case 1:
out.EmailAddresses = append(out.EmailAddresses, string(v.Bytes))
parsedName = true
case 2:
out.DNSNames = append(out.DNSNames, string(v.Bytes))
parsedName = true
case 7:
switch len(v.Bytes) {
case net.IPv4len, net.IPv6len:
out.IPAddresses = append(out.IPAddresses, v.Bytes)
default:
return nil, errors.New("x509: certificate contained IP address of length " + strconv.Itoa(len(v.Bytes)))
}
}
}
if parsedName {
continue
}
// If we didn't parse any of the names then we
// fall through to the critical check below.
case 30:
// RFC 5280, 4.2.1.10
// NameConstraints ::= SEQUENCE {
// permittedSubtrees [0] GeneralSubtrees OPTIONAL,
// excludedSubtrees [1] GeneralSubtrees OPTIONAL }
//
// GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree
//
// GeneralSubtree ::= SEQUENCE {
// base GeneralName,
// minimum [0] BaseDistance DEFAULT 0,
// maximum [1] BaseDistance OPTIONAL }
//
// BaseDistance ::= INTEGER (0..MAX)
var constraints nameConstraints
_, err := asn1.Unmarshal(e.Value, &constraints)
if err != nil {
return nil, err
}
if len(constraints.Excluded) > 0 && e.Critical {
return out, UnhandledCriticalExtension{}
}
for _, subtree := range constraints.Permitted {
if len(subtree.Name) == 0 {
if e.Critical {
return out, UnhandledCriticalExtension{}
}
continue
}
out.PermittedDNSDomains = append(out.PermittedDNSDomains, subtree.Name)
}
continue
case 31:
// RFC 5280, 4.2.1.14
// CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint
//
// DistributionPoint ::= SEQUENCE {
// distributionPoint [0] DistributionPointName OPTIONAL,
// reasons [1] ReasonFlags OPTIONAL,
// cRLIssuer [2] GeneralNames OPTIONAL }
//
// DistributionPointName ::= CHOICE {
// fullName [0] GeneralNames,
// nameRelativeToCRLIssuer [1] RelativeDistinguishedName }
var cdp []distributionPoint
_, err := asn1.Unmarshal(e.Value, &cdp)
if err != nil {
return nil, err
}
for _, dp := range cdp {
var n asn1.RawValue
_, err = asn1.Unmarshal(dp.DistributionPoint.FullName.Bytes, &n)
if err != nil {
return nil, err
}
if n.Tag == 6 {
out.CRLDistributionPoints = append(out.CRLDistributionPoints, string(n.Bytes))
}
}
continue
case 35:
// RFC 5280, 4.2.1.1
var a authKeyId
_, err = asn1.Unmarshal(e.Value, &a)
if err != nil {
return nil, err
}
out.AuthorityKeyId = a.Id
continue
case 37:
// RFC 5280, 4.2.1.12. Extended Key Usage
// id-ce-extKeyUsage OBJECT IDENTIFIER ::= { id-ce 37 }
//
// ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
//
// KeyPurposeId ::= OBJECT IDENTIFIER
var keyUsage []asn1.ObjectIdentifier
_, err = asn1.Unmarshal(e.Value, &keyUsage)
if err != nil {
return nil, err
}
for _, u := range keyUsage {
if extKeyUsage, ok := extKeyUsageFromOID(u); ok {
out.ExtKeyUsage = append(out.ExtKeyUsage, extKeyUsage)
} else {
out.UnknownExtKeyUsage = append(out.UnknownExtKeyUsage, u)
}
}
continue
case 14:
// RFC 5280, 4.2.1.2
var keyid []byte
_, err = asn1.Unmarshal(e.Value, &keyid)
if err != nil {
return nil, err
}
out.SubjectKeyId = keyid
continue
case 32:
// RFC 5280 4.2.1.4: Certificate Policies
var policies []policyInformation
if _, err = asn1.Unmarshal(e.Value, &policies); err != nil {
return nil, err
}
out.PolicyIdentifiers = make([]asn1.ObjectIdentifier, len(policies))
for i, policy := range policies {
out.PolicyIdentifiers[i] = policy.Policy
}
}
} else if e.Id.Equal(oidExtensionAuthorityInfoAccess) {
// RFC 5280 4.2.2.1: Authority Information Access
var aia []authorityInfoAccess
if _, err = asn1.Unmarshal(e.Value, &aia); err != nil {
return nil, err
}
for _, v := range aia {
// GeneralName: uniformResourceIdentifier [6] IA5String
if v.Location.Tag != 6 {
continue
}
if v.Method.Equal(oidAuthorityInfoAccessOcsp) {
out.OCSPServer = append(out.OCSPServer, string(v.Location.Bytes))
} else if v.Method.Equal(oidAuthorityInfoAccessIssuers) {
out.IssuingCertificateURL = append(out.IssuingCertificateURL, string(v.Location.Bytes))
}
}
}
if e.Critical {
return out, UnhandledCriticalExtension{}
}
}
return out, nil
}