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-rw-r--r--src/crypto/x509/parser.go1193
1 files changed, 1193 insertions, 0 deletions
diff --git a/src/crypto/x509/parser.go b/src/crypto/x509/parser.go
new file mode 100644
index 0000000..6695212
--- /dev/null
+++ b/src/crypto/x509/parser.go
@@ -0,0 +1,1193 @@
+// Copyright 2021 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
+
+import (
+ "bytes"
+ "crypto/dsa"
+ "crypto/ecdh"
+ "crypto/ecdsa"
+ "crypto/ed25519"
+ "crypto/elliptic"
+ "crypto/rsa"
+ "crypto/x509/pkix"
+ "encoding/asn1"
+ "errors"
+ "fmt"
+ "math/big"
+ "net"
+ "net/url"
+ "strconv"
+ "strings"
+ "time"
+ "unicode/utf16"
+ "unicode/utf8"
+
+ "golang.org/x/crypto/cryptobyte"
+ cryptobyte_asn1 "golang.org/x/crypto/cryptobyte/asn1"
+)
+
+// isPrintable reports whether the given b is in the ASN.1 PrintableString set.
+// This is a simplified version of encoding/asn1.isPrintable.
+func isPrintable(b byte) bool {
+ return 'a' <= b && b <= 'z' ||
+ 'A' <= b && b <= 'Z' ||
+ '0' <= b && b <= '9' ||
+ '\'' <= b && b <= ')' ||
+ '+' <= b && b <= '/' ||
+ b == ' ' ||
+ b == ':' ||
+ b == '=' ||
+ b == '?' ||
+ // This is technically not allowed in a PrintableString.
+ // However, x509 certificates with wildcard strings don't
+ // always use the correct string type so we permit it.
+ b == '*' ||
+ // This is not technically allowed either. However, not
+ // only is it relatively common, but there are also a
+ // handful of CA certificates that contain it. At least
+ // one of which will not expire until 2027.
+ b == '&'
+}
+
+// parseASN1String parses the ASN.1 string types T61String, PrintableString,
+// UTF8String, BMPString, IA5String, and NumericString. This is mostly copied
+// from the respective encoding/asn1.parse... methods, rather than just
+// increasing the API surface of that package.
+func parseASN1String(tag cryptobyte_asn1.Tag, value []byte) (string, error) {
+ switch tag {
+ case cryptobyte_asn1.T61String:
+ return string(value), nil
+ case cryptobyte_asn1.PrintableString:
+ for _, b := range value {
+ if !isPrintable(b) {
+ return "", errors.New("invalid PrintableString")
+ }
+ }
+ return string(value), nil
+ case cryptobyte_asn1.UTF8String:
+ if !utf8.Valid(value) {
+ return "", errors.New("invalid UTF-8 string")
+ }
+ return string(value), nil
+ case cryptobyte_asn1.Tag(asn1.TagBMPString):
+ if len(value)%2 != 0 {
+ return "", errors.New("invalid BMPString")
+ }
+
+ // Strip terminator if present.
+ if l := len(value); l >= 2 && value[l-1] == 0 && value[l-2] == 0 {
+ value = value[:l-2]
+ }
+
+ s := make([]uint16, 0, len(value)/2)
+ for len(value) > 0 {
+ s = append(s, uint16(value[0])<<8+uint16(value[1]))
+ value = value[2:]
+ }
+
+ return string(utf16.Decode(s)), nil
+ case cryptobyte_asn1.IA5String:
+ s := string(value)
+ if isIA5String(s) != nil {
+ return "", errors.New("invalid IA5String")
+ }
+ return s, nil
+ case cryptobyte_asn1.Tag(asn1.TagNumericString):
+ for _, b := range value {
+ if !('0' <= b && b <= '9' || b == ' ') {
+ return "", errors.New("invalid NumericString")
+ }
+ }
+ return string(value), nil
+ }
+ return "", fmt.Errorf("unsupported string type: %v", tag)
+}
+
+// parseName parses a DER encoded Name as defined in RFC 5280. We may
+// want to export this function in the future for use in crypto/tls.
+func parseName(raw cryptobyte.String) (*pkix.RDNSequence, error) {
+ if !raw.ReadASN1(&raw, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: invalid RDNSequence")
+ }
+
+ var rdnSeq pkix.RDNSequence
+ for !raw.Empty() {
+ var rdnSet pkix.RelativeDistinguishedNameSET
+ var set cryptobyte.String
+ if !raw.ReadASN1(&set, cryptobyte_asn1.SET) {
+ return nil, errors.New("x509: invalid RDNSequence")
+ }
+ for !set.Empty() {
+ var atav cryptobyte.String
+ if !set.ReadASN1(&atav, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: invalid RDNSequence: invalid attribute")
+ }
+ var attr pkix.AttributeTypeAndValue
+ if !atav.ReadASN1ObjectIdentifier(&attr.Type) {
+ return nil, errors.New("x509: invalid RDNSequence: invalid attribute type")
+ }
+ var rawValue cryptobyte.String
+ var valueTag cryptobyte_asn1.Tag
+ if !atav.ReadAnyASN1(&rawValue, &valueTag) {
+ return nil, errors.New("x509: invalid RDNSequence: invalid attribute value")
+ }
+ var err error
+ attr.Value, err = parseASN1String(valueTag, rawValue)
+ if err != nil {
+ return nil, fmt.Errorf("x509: invalid RDNSequence: invalid attribute value: %s", err)
+ }
+ rdnSet = append(rdnSet, attr)
+ }
+
+ rdnSeq = append(rdnSeq, rdnSet)
+ }
+
+ return &rdnSeq, nil
+}
+
+func parseAI(der cryptobyte.String) (pkix.AlgorithmIdentifier, error) {
+ ai := pkix.AlgorithmIdentifier{}
+ if !der.ReadASN1ObjectIdentifier(&ai.Algorithm) {
+ return ai, errors.New("x509: malformed OID")
+ }
+ if der.Empty() {
+ return ai, nil
+ }
+ var params cryptobyte.String
+ var tag cryptobyte_asn1.Tag
+ if !der.ReadAnyASN1Element(&params, &tag) {
+ return ai, errors.New("x509: malformed parameters")
+ }
+ ai.Parameters.Tag = int(tag)
+ ai.Parameters.FullBytes = params
+ return ai, nil
+}
+
+func parseTime(der *cryptobyte.String) (time.Time, error) {
+ var t time.Time
+ switch {
+ case der.PeekASN1Tag(cryptobyte_asn1.UTCTime):
+ if !der.ReadASN1UTCTime(&t) {
+ return t, errors.New("x509: malformed UTCTime")
+ }
+ case der.PeekASN1Tag(cryptobyte_asn1.GeneralizedTime):
+ if !der.ReadASN1GeneralizedTime(&t) {
+ return t, errors.New("x509: malformed GeneralizedTime")
+ }
+ default:
+ return t, errors.New("x509: unsupported time format")
+ }
+ return t, nil
+}
+
+func parseValidity(der cryptobyte.String) (time.Time, time.Time, error) {
+ notBefore, err := parseTime(&der)
+ if err != nil {
+ return time.Time{}, time.Time{}, err
+ }
+ notAfter, err := parseTime(&der)
+ if err != nil {
+ return time.Time{}, time.Time{}, err
+ }
+
+ return notBefore, notAfter, nil
+}
+
+func parseExtension(der cryptobyte.String) (pkix.Extension, error) {
+ var ext pkix.Extension
+ if !der.ReadASN1ObjectIdentifier(&ext.Id) {
+ return ext, errors.New("x509: malformed extension OID field")
+ }
+ if der.PeekASN1Tag(cryptobyte_asn1.BOOLEAN) {
+ if !der.ReadASN1Boolean(&ext.Critical) {
+ return ext, errors.New("x509: malformed extension critical field")
+ }
+ }
+ var val cryptobyte.String
+ if !der.ReadASN1(&val, cryptobyte_asn1.OCTET_STRING) {
+ return ext, errors.New("x509: malformed extension value field")
+ }
+ ext.Value = val
+ return ext, nil
+}
+
+func parsePublicKey(keyData *publicKeyInfo) (any, error) {
+ oid := keyData.Algorithm.Algorithm
+ params := keyData.Algorithm.Parameters
+ der := cryptobyte.String(keyData.PublicKey.RightAlign())
+ switch {
+ case oid.Equal(oidPublicKeyRSA):
+ // RSA public keys must have a NULL in the parameters.
+ // See RFC 3279, Section 2.3.1.
+ if !bytes.Equal(params.FullBytes, asn1.NullBytes) {
+ return nil, errors.New("x509: RSA key missing NULL parameters")
+ }
+
+ p := &pkcs1PublicKey{N: new(big.Int)}
+ if !der.ReadASN1(&der, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: invalid RSA public key")
+ }
+ if !der.ReadASN1Integer(p.N) {
+ return nil, errors.New("x509: invalid RSA modulus")
+ }
+ if !der.ReadASN1Integer(&p.E) {
+ return nil, errors.New("x509: invalid RSA public exponent")
+ }
+
+ if p.N.Sign() <= 0 {
+ return nil, errors.New("x509: RSA modulus is not a positive number")
+ }
+ if p.E <= 0 {
+ return nil, errors.New("x509: RSA public exponent is not a positive number")
+ }
+
+ pub := &rsa.PublicKey{
+ E: p.E,
+ N: p.N,
+ }
+ return pub, nil
+ case oid.Equal(oidPublicKeyECDSA):
+ paramsDer := cryptobyte.String(params.FullBytes)
+ namedCurveOID := new(asn1.ObjectIdentifier)
+ if !paramsDer.ReadASN1ObjectIdentifier(namedCurveOID) {
+ return nil, errors.New("x509: invalid ECDSA parameters")
+ }
+ namedCurve := namedCurveFromOID(*namedCurveOID)
+ if namedCurve == nil {
+ return nil, errors.New("x509: unsupported elliptic curve")
+ }
+ x, y := elliptic.Unmarshal(namedCurve, der)
+ if x == nil {
+ return nil, errors.New("x509: failed to unmarshal elliptic curve point")
+ }
+ pub := &ecdsa.PublicKey{
+ Curve: namedCurve,
+ X: x,
+ Y: y,
+ }
+ return pub, nil
+ case oid.Equal(oidPublicKeyEd25519):
+ // RFC 8410, Section 3
+ // > For all of the OIDs, the parameters MUST be absent.
+ if len(params.FullBytes) != 0 {
+ return nil, errors.New("x509: Ed25519 key encoded with illegal parameters")
+ }
+ if len(der) != ed25519.PublicKeySize {
+ return nil, errors.New("x509: wrong Ed25519 public key size")
+ }
+ return ed25519.PublicKey(der), nil
+ case oid.Equal(oidPublicKeyX25519):
+ // RFC 8410, Section 3
+ // > For all of the OIDs, the parameters MUST be absent.
+ if len(params.FullBytes) != 0 {
+ return nil, errors.New("x509: X25519 key encoded with illegal parameters")
+ }
+ return ecdh.X25519().NewPublicKey(der)
+ case oid.Equal(oidPublicKeyDSA):
+ y := new(big.Int)
+ if !der.ReadASN1Integer(y) {
+ return nil, errors.New("x509: invalid DSA public key")
+ }
+ pub := &dsa.PublicKey{
+ Y: y,
+ Parameters: dsa.Parameters{
+ P: new(big.Int),
+ Q: new(big.Int),
+ G: new(big.Int),
+ },
+ }
+ paramsDer := cryptobyte.String(params.FullBytes)
+ if !paramsDer.ReadASN1(&paramsDer, cryptobyte_asn1.SEQUENCE) ||
+ !paramsDer.ReadASN1Integer(pub.Parameters.P) ||
+ !paramsDer.ReadASN1Integer(pub.Parameters.Q) ||
+ !paramsDer.ReadASN1Integer(pub.Parameters.G) {
+ return nil, errors.New("x509: invalid DSA parameters")
+ }
+ if pub.Y.Sign() <= 0 || pub.Parameters.P.Sign() <= 0 ||
+ pub.Parameters.Q.Sign() <= 0 || pub.Parameters.G.Sign() <= 0 {
+ return nil, errors.New("x509: zero or negative DSA parameter")
+ }
+ return pub, nil
+ default:
+ return nil, errors.New("x509: unknown public key algorithm")
+ }
+}
+
+func parseKeyUsageExtension(der cryptobyte.String) (KeyUsage, error) {
+ var usageBits asn1.BitString
+ if !der.ReadASN1BitString(&usageBits) {
+ return 0, errors.New("x509: invalid key usage")
+ }
+
+ var usage int
+ for i := 0; i < 9; i++ {
+ if usageBits.At(i) != 0 {
+ usage |= 1 << uint(i)
+ }
+ }
+ return KeyUsage(usage), nil
+}
+
+func parseBasicConstraintsExtension(der cryptobyte.String) (bool, int, error) {
+ var isCA bool
+ if !der.ReadASN1(&der, cryptobyte_asn1.SEQUENCE) {
+ return false, 0, errors.New("x509: invalid basic constraints")
+ }
+ if der.PeekASN1Tag(cryptobyte_asn1.BOOLEAN) {
+ if !der.ReadASN1Boolean(&isCA) {
+ return false, 0, errors.New("x509: invalid basic constraints")
+ }
+ }
+ maxPathLen := -1
+ if der.PeekASN1Tag(cryptobyte_asn1.INTEGER) {
+ if !der.ReadASN1Integer(&maxPathLen) {
+ return false, 0, errors.New("x509: invalid basic constraints")
+ }
+ }
+
+ // TODO: map out.MaxPathLen to 0 if it has the -1 default value? (Issue 19285)
+ return isCA, maxPathLen, nil
+}
+
+func forEachSAN(der cryptobyte.String, callback func(tag int, data []byte) error) error {
+ if !der.ReadASN1(&der, cryptobyte_asn1.SEQUENCE) {
+ return errors.New("x509: invalid subject alternative names")
+ }
+ for !der.Empty() {
+ var san cryptobyte.String
+ var tag cryptobyte_asn1.Tag
+ if !der.ReadAnyASN1(&san, &tag) {
+ return errors.New("x509: invalid subject alternative name")
+ }
+ if err := callback(int(tag^0x80), san); err != nil {
+ return err
+ }
+ }
+
+ return nil
+}
+
+func parseSANExtension(der cryptobyte.String) (dnsNames, emailAddresses []string, ipAddresses []net.IP, uris []*url.URL, err error) {
+ err = forEachSAN(der, func(tag int, data []byte) error {
+ switch tag {
+ case nameTypeEmail:
+ email := string(data)
+ if err := isIA5String(email); err != nil {
+ return errors.New("x509: SAN rfc822Name is malformed")
+ }
+ emailAddresses = append(emailAddresses, email)
+ case nameTypeDNS:
+ name := string(data)
+ if err := isIA5String(name); err != nil {
+ return errors.New("x509: SAN dNSName is malformed")
+ }
+ dnsNames = append(dnsNames, string(name))
+ case nameTypeURI:
+ uriStr := string(data)
+ if err := isIA5String(uriStr); err != nil {
+ return errors.New("x509: SAN uniformResourceIdentifier is malformed")
+ }
+ uri, err := url.Parse(uriStr)
+ if err != nil {
+ return fmt.Errorf("x509: cannot parse URI %q: %s", uriStr, err)
+ }
+ if len(uri.Host) > 0 {
+ if _, ok := domainToReverseLabels(uri.Host); !ok {
+ return fmt.Errorf("x509: cannot parse URI %q: invalid domain", uriStr)
+ }
+ }
+ uris = append(uris, uri)
+ case nameTypeIP:
+ switch len(data) {
+ case net.IPv4len, net.IPv6len:
+ ipAddresses = append(ipAddresses, data)
+ default:
+ return errors.New("x509: cannot parse IP address of length " + strconv.Itoa(len(data)))
+ }
+ }
+
+ return nil
+ })
+
+ return
+}
+
+func parseExtKeyUsageExtension(der cryptobyte.String) ([]ExtKeyUsage, []asn1.ObjectIdentifier, error) {
+ var extKeyUsages []ExtKeyUsage
+ var unknownUsages []asn1.ObjectIdentifier
+ if !der.ReadASN1(&der, cryptobyte_asn1.SEQUENCE) {
+ return nil, nil, errors.New("x509: invalid extended key usages")
+ }
+ for !der.Empty() {
+ var eku asn1.ObjectIdentifier
+ if !der.ReadASN1ObjectIdentifier(&eku) {
+ return nil, nil, errors.New("x509: invalid extended key usages")
+ }
+ if extKeyUsage, ok := extKeyUsageFromOID(eku); ok {
+ extKeyUsages = append(extKeyUsages, extKeyUsage)
+ } else {
+ unknownUsages = append(unknownUsages, eku)
+ }
+ }
+ return extKeyUsages, unknownUsages, nil
+}
+
+func parseCertificatePoliciesExtension(der cryptobyte.String) ([]asn1.ObjectIdentifier, error) {
+ var oids []asn1.ObjectIdentifier
+ if !der.ReadASN1(&der, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: invalid certificate policies")
+ }
+ for !der.Empty() {
+ var cp cryptobyte.String
+ if !der.ReadASN1(&cp, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: invalid certificate policies")
+ }
+ var oid asn1.ObjectIdentifier
+ if !cp.ReadASN1ObjectIdentifier(&oid) {
+ return nil, errors.New("x509: invalid certificate policies")
+ }
+ oids = append(oids, oid)
+ }
+
+ return oids, nil
+}
+
+// isValidIPMask reports whether mask consists of zero or more 1 bits, followed by zero bits.
+func isValidIPMask(mask []byte) bool {
+ seenZero := false
+
+ for _, b := range mask {
+ if seenZero {
+ if b != 0 {
+ return false
+ }
+
+ continue
+ }
+
+ switch b {
+ case 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe:
+ seenZero = true
+ case 0xff:
+ default:
+ return false
+ }
+ }
+
+ return true
+}
+
+func parseNameConstraintsExtension(out *Certificate, e pkix.Extension) (unhandled bool, err error) {
+ // 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)
+
+ outer := cryptobyte.String(e.Value)
+ var toplevel, permitted, excluded cryptobyte.String
+ var havePermitted, haveExcluded bool
+ if !outer.ReadASN1(&toplevel, cryptobyte_asn1.SEQUENCE) ||
+ !outer.Empty() ||
+ !toplevel.ReadOptionalASN1(&permitted, &havePermitted, cryptobyte_asn1.Tag(0).ContextSpecific().Constructed()) ||
+ !toplevel.ReadOptionalASN1(&excluded, &haveExcluded, cryptobyte_asn1.Tag(1).ContextSpecific().Constructed()) ||
+ !toplevel.Empty() {
+ return false, errors.New("x509: invalid NameConstraints extension")
+ }
+
+ if !havePermitted && !haveExcluded || len(permitted) == 0 && len(excluded) == 0 {
+ // From RFC 5280, Section 4.2.1.10:
+ // “either the permittedSubtrees field
+ // or the excludedSubtrees MUST be
+ // present”
+ return false, errors.New("x509: empty name constraints extension")
+ }
+
+ getValues := func(subtrees cryptobyte.String) (dnsNames []string, ips []*net.IPNet, emails, uriDomains []string, err error) {
+ for !subtrees.Empty() {
+ var seq, value cryptobyte.String
+ var tag cryptobyte_asn1.Tag
+ if !subtrees.ReadASN1(&seq, cryptobyte_asn1.SEQUENCE) ||
+ !seq.ReadAnyASN1(&value, &tag) {
+ return nil, nil, nil, nil, fmt.Errorf("x509: invalid NameConstraints extension")
+ }
+
+ var (
+ dnsTag = cryptobyte_asn1.Tag(2).ContextSpecific()
+ emailTag = cryptobyte_asn1.Tag(1).ContextSpecific()
+ ipTag = cryptobyte_asn1.Tag(7).ContextSpecific()
+ uriTag = cryptobyte_asn1.Tag(6).ContextSpecific()
+ )
+
+ switch tag {
+ case dnsTag:
+ domain := string(value)
+ if err := isIA5String(domain); err != nil {
+ return nil, nil, nil, nil, errors.New("x509: invalid constraint value: " + err.Error())
+ }
+
+ trimmedDomain := domain
+ if len(trimmedDomain) > 0 && trimmedDomain[0] == '.' {
+ // constraints can have a leading
+ // period to exclude the domain
+ // itself, but that's not valid in a
+ // normal domain name.
+ trimmedDomain = trimmedDomain[1:]
+ }
+ if _, ok := domainToReverseLabels(trimmedDomain); !ok {
+ return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse dnsName constraint %q", domain)
+ }
+ dnsNames = append(dnsNames, domain)
+
+ case ipTag:
+ l := len(value)
+ var ip, mask []byte
+
+ switch l {
+ case 8:
+ ip = value[:4]
+ mask = value[4:]
+
+ case 32:
+ ip = value[:16]
+ mask = value[16:]
+
+ default:
+ return nil, nil, nil, nil, fmt.Errorf("x509: IP constraint contained value of length %d", l)
+ }
+
+ if !isValidIPMask(mask) {
+ return nil, nil, nil, nil, fmt.Errorf("x509: IP constraint contained invalid mask %x", mask)
+ }
+
+ ips = append(ips, &net.IPNet{IP: net.IP(ip), Mask: net.IPMask(mask)})
+
+ case emailTag:
+ constraint := string(value)
+ if err := isIA5String(constraint); err != nil {
+ return nil, nil, nil, nil, errors.New("x509: invalid constraint value: " + err.Error())
+ }
+
+ // If the constraint contains an @ then
+ // it specifies an exact mailbox name.
+ if strings.Contains(constraint, "@") {
+ if _, ok := parseRFC2821Mailbox(constraint); !ok {
+ return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse rfc822Name constraint %q", constraint)
+ }
+ } else {
+ // Otherwise it's a domain name.
+ domain := constraint
+ if len(domain) > 0 && domain[0] == '.' {
+ domain = domain[1:]
+ }
+ if _, ok := domainToReverseLabels(domain); !ok {
+ return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse rfc822Name constraint %q", constraint)
+ }
+ }
+ emails = append(emails, constraint)
+
+ case uriTag:
+ domain := string(value)
+ if err := isIA5String(domain); err != nil {
+ return nil, nil, nil, nil, errors.New("x509: invalid constraint value: " + err.Error())
+ }
+
+ if net.ParseIP(domain) != nil {
+ return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse URI constraint %q: cannot be IP address", domain)
+ }
+
+ trimmedDomain := domain
+ if len(trimmedDomain) > 0 && trimmedDomain[0] == '.' {
+ // constraints can have a leading
+ // period to exclude the domain itself,
+ // but that's not valid in a normal
+ // domain name.
+ trimmedDomain = trimmedDomain[1:]
+ }
+ if _, ok := domainToReverseLabels(trimmedDomain); !ok {
+ return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse URI constraint %q", domain)
+ }
+ uriDomains = append(uriDomains, domain)
+
+ default:
+ unhandled = true
+ }
+ }
+
+ return dnsNames, ips, emails, uriDomains, nil
+ }
+
+ if out.PermittedDNSDomains, out.PermittedIPRanges, out.PermittedEmailAddresses, out.PermittedURIDomains, err = getValues(permitted); err != nil {
+ return false, err
+ }
+ if out.ExcludedDNSDomains, out.ExcludedIPRanges, out.ExcludedEmailAddresses, out.ExcludedURIDomains, err = getValues(excluded); err != nil {
+ return false, err
+ }
+ out.PermittedDNSDomainsCritical = e.Critical
+
+ return unhandled, nil
+}
+
+func processExtensions(out *Certificate) error {
+ var err error
+ for _, e := range out.Extensions {
+ unhandled := false
+
+ if len(e.Id) == 4 && e.Id[0] == 2 && e.Id[1] == 5 && e.Id[2] == 29 {
+ switch e.Id[3] {
+ case 15:
+ out.KeyUsage, err = parseKeyUsageExtension(e.Value)
+ if err != nil {
+ return err
+ }
+ case 19:
+ out.IsCA, out.MaxPathLen, err = parseBasicConstraintsExtension(e.Value)
+ if err != nil {
+ return err
+ }
+ out.BasicConstraintsValid = true
+ out.MaxPathLenZero = out.MaxPathLen == 0
+ case 17:
+ out.DNSNames, out.EmailAddresses, out.IPAddresses, out.URIs, err = parseSANExtension(e.Value)
+ if err != nil {
+ return err
+ }
+
+ if len(out.DNSNames) == 0 && len(out.EmailAddresses) == 0 && len(out.IPAddresses) == 0 && len(out.URIs) == 0 {
+ // If we didn't parse anything then we do the critical check, below.
+ unhandled = true
+ }
+
+ case 30:
+ unhandled, err = parseNameConstraintsExtension(out, e)
+ if err != nil {
+ return err
+ }
+
+ case 31:
+ // RFC 5280, 4.2.1.13
+
+ // 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 }
+ val := cryptobyte.String(e.Value)
+ if !val.ReadASN1(&val, cryptobyte_asn1.SEQUENCE) {
+ return errors.New("x509: invalid CRL distribution points")
+ }
+ for !val.Empty() {
+ var dpDER cryptobyte.String
+ if !val.ReadASN1(&dpDER, cryptobyte_asn1.SEQUENCE) {
+ return errors.New("x509: invalid CRL distribution point")
+ }
+ var dpNameDER cryptobyte.String
+ var dpNamePresent bool
+ if !dpDER.ReadOptionalASN1(&dpNameDER, &dpNamePresent, cryptobyte_asn1.Tag(0).Constructed().ContextSpecific()) {
+ return errors.New("x509: invalid CRL distribution point")
+ }
+ if !dpNamePresent {
+ continue
+ }
+ if !dpNameDER.ReadASN1(&dpNameDER, cryptobyte_asn1.Tag(0).Constructed().ContextSpecific()) {
+ return errors.New("x509: invalid CRL distribution point")
+ }
+ for !dpNameDER.Empty() {
+ if !dpNameDER.PeekASN1Tag(cryptobyte_asn1.Tag(6).ContextSpecific()) {
+ break
+ }
+ var uri cryptobyte.String
+ if !dpNameDER.ReadASN1(&uri, cryptobyte_asn1.Tag(6).ContextSpecific()) {
+ return errors.New("x509: invalid CRL distribution point")
+ }
+ out.CRLDistributionPoints = append(out.CRLDistributionPoints, string(uri))
+ }
+ }
+
+ case 35:
+ // RFC 5280, 4.2.1.1
+ val := cryptobyte.String(e.Value)
+ var akid cryptobyte.String
+ if !val.ReadASN1(&akid, cryptobyte_asn1.SEQUENCE) {
+ return errors.New("x509: invalid authority key identifier")
+ }
+ if akid.PeekASN1Tag(cryptobyte_asn1.Tag(0).ContextSpecific()) {
+ if !akid.ReadASN1(&akid, cryptobyte_asn1.Tag(0).ContextSpecific()) {
+ return errors.New("x509: invalid authority key identifier")
+ }
+ out.AuthorityKeyId = akid
+ }
+ case 37:
+ out.ExtKeyUsage, out.UnknownExtKeyUsage, err = parseExtKeyUsageExtension(e.Value)
+ if err != nil {
+ return err
+ }
+ case 14:
+ // RFC 5280, 4.2.1.2
+ val := cryptobyte.String(e.Value)
+ var skid cryptobyte.String
+ if !val.ReadASN1(&skid, cryptobyte_asn1.OCTET_STRING) {
+ return errors.New("x509: invalid subject key identifier")
+ }
+ out.SubjectKeyId = skid
+ case 32:
+ out.PolicyIdentifiers, err = parseCertificatePoliciesExtension(e.Value)
+ if err != nil {
+ return err
+ }
+ default:
+ // Unknown extensions are recorded if critical.
+ unhandled = true
+ }
+ } else if e.Id.Equal(oidExtensionAuthorityInfoAccess) {
+ // RFC 5280 4.2.2.1: Authority Information Access
+ val := cryptobyte.String(e.Value)
+ if !val.ReadASN1(&val, cryptobyte_asn1.SEQUENCE) {
+ return errors.New("x509: invalid authority info access")
+ }
+ for !val.Empty() {
+ var aiaDER cryptobyte.String
+ if !val.ReadASN1(&aiaDER, cryptobyte_asn1.SEQUENCE) {
+ return errors.New("x509: invalid authority info access")
+ }
+ var method asn1.ObjectIdentifier
+ if !aiaDER.ReadASN1ObjectIdentifier(&method) {
+ return errors.New("x509: invalid authority info access")
+ }
+ if !aiaDER.PeekASN1Tag(cryptobyte_asn1.Tag(6).ContextSpecific()) {
+ continue
+ }
+ if !aiaDER.ReadASN1(&aiaDER, cryptobyte_asn1.Tag(6).ContextSpecific()) {
+ return errors.New("x509: invalid authority info access")
+ }
+ switch {
+ case method.Equal(oidAuthorityInfoAccessOcsp):
+ out.OCSPServer = append(out.OCSPServer, string(aiaDER))
+ case method.Equal(oidAuthorityInfoAccessIssuers):
+ out.IssuingCertificateURL = append(out.IssuingCertificateURL, string(aiaDER))
+ }
+ }
+ } else {
+ // Unknown extensions are recorded if critical.
+ unhandled = true
+ }
+
+ if e.Critical && unhandled {
+ out.UnhandledCriticalExtensions = append(out.UnhandledCriticalExtensions, e.Id)
+ }
+ }
+
+ return nil
+}
+
+func parseCertificate(der []byte) (*Certificate, error) {
+ cert := &Certificate{}
+
+ input := cryptobyte.String(der)
+ // we read the SEQUENCE including length and tag bytes so that
+ // we can populate Certificate.Raw, before unwrapping the
+ // SEQUENCE so it can be operated on
+ if !input.ReadASN1Element(&input, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed certificate")
+ }
+ cert.Raw = input
+ if !input.ReadASN1(&input, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed certificate")
+ }
+
+ var tbs cryptobyte.String
+ // do the same trick again as above to extract the raw
+ // bytes for Certificate.RawTBSCertificate
+ if !input.ReadASN1Element(&tbs, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed tbs certificate")
+ }
+ cert.RawTBSCertificate = tbs
+ if !tbs.ReadASN1(&tbs, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed tbs certificate")
+ }
+
+ if !tbs.ReadOptionalASN1Integer(&cert.Version, cryptobyte_asn1.Tag(0).Constructed().ContextSpecific(), 0) {
+ return nil, errors.New("x509: malformed version")
+ }
+ if cert.Version < 0 {
+ return nil, errors.New("x509: malformed version")
+ }
+ // for backwards compat reasons Version is one-indexed,
+ // rather than zero-indexed as defined in 5280
+ cert.Version++
+ if cert.Version > 3 {
+ return nil, errors.New("x509: invalid version")
+ }
+
+ serial := new(big.Int)
+ if !tbs.ReadASN1Integer(serial) {
+ return nil, errors.New("x509: malformed serial number")
+ }
+ // we ignore the presence of negative serial numbers because
+ // of their prevalence, despite them being invalid
+ // TODO(rolandshoemaker): revisit this decision, there are currently
+ // only 10 trusted certificates with negative serial numbers
+ // according to censys.io.
+ cert.SerialNumber = serial
+
+ var sigAISeq cryptobyte.String
+ if !tbs.ReadASN1(&sigAISeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed signature algorithm identifier")
+ }
+ // Before parsing the inner algorithm identifier, extract
+ // the outer algorithm identifier and make sure that they
+ // match.
+ var outerSigAISeq cryptobyte.String
+ if !input.ReadASN1(&outerSigAISeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed algorithm identifier")
+ }
+ if !bytes.Equal(outerSigAISeq, sigAISeq) {
+ return nil, errors.New("x509: inner and outer signature algorithm identifiers don't match")
+ }
+ sigAI, err := parseAI(sigAISeq)
+ if err != nil {
+ return nil, err
+ }
+ cert.SignatureAlgorithm = getSignatureAlgorithmFromAI(sigAI)
+
+ var issuerSeq cryptobyte.String
+ if !tbs.ReadASN1Element(&issuerSeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed issuer")
+ }
+ cert.RawIssuer = issuerSeq
+ issuerRDNs, err := parseName(issuerSeq)
+ if err != nil {
+ return nil, err
+ }
+ cert.Issuer.FillFromRDNSequence(issuerRDNs)
+
+ var validity cryptobyte.String
+ if !tbs.ReadASN1(&validity, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed validity")
+ }
+ cert.NotBefore, cert.NotAfter, err = parseValidity(validity)
+ if err != nil {
+ return nil, err
+ }
+
+ var subjectSeq cryptobyte.String
+ if !tbs.ReadASN1Element(&subjectSeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed issuer")
+ }
+ cert.RawSubject = subjectSeq
+ subjectRDNs, err := parseName(subjectSeq)
+ if err != nil {
+ return nil, err
+ }
+ cert.Subject.FillFromRDNSequence(subjectRDNs)
+
+ var spki cryptobyte.String
+ if !tbs.ReadASN1Element(&spki, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed spki")
+ }
+ cert.RawSubjectPublicKeyInfo = spki
+ if !spki.ReadASN1(&spki, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed spki")
+ }
+ var pkAISeq cryptobyte.String
+ if !spki.ReadASN1(&pkAISeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed public key algorithm identifier")
+ }
+ pkAI, err := parseAI(pkAISeq)
+ if err != nil {
+ return nil, err
+ }
+ cert.PublicKeyAlgorithm = getPublicKeyAlgorithmFromOID(pkAI.Algorithm)
+ var spk asn1.BitString
+ if !spki.ReadASN1BitString(&spk) {
+ return nil, errors.New("x509: malformed subjectPublicKey")
+ }
+ if cert.PublicKeyAlgorithm != UnknownPublicKeyAlgorithm {
+ cert.PublicKey, err = parsePublicKey(&publicKeyInfo{
+ Algorithm: pkAI,
+ PublicKey: spk,
+ })
+ if err != nil {
+ return nil, err
+ }
+ }
+
+ if cert.Version > 1 {
+ if !tbs.SkipOptionalASN1(cryptobyte_asn1.Tag(1).ContextSpecific()) {
+ return nil, errors.New("x509: malformed issuerUniqueID")
+ }
+ if !tbs.SkipOptionalASN1(cryptobyte_asn1.Tag(2).ContextSpecific()) {
+ return nil, errors.New("x509: malformed subjectUniqueID")
+ }
+ if cert.Version == 3 {
+ var extensions cryptobyte.String
+ var present bool
+ if !tbs.ReadOptionalASN1(&extensions, &present, cryptobyte_asn1.Tag(3).Constructed().ContextSpecific()) {
+ return nil, errors.New("x509: malformed extensions")
+ }
+ if present {
+ seenExts := make(map[string]bool)
+ if !extensions.ReadASN1(&extensions, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed extensions")
+ }
+ for !extensions.Empty() {
+ var extension cryptobyte.String
+ if !extensions.ReadASN1(&extension, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed extension")
+ }
+ ext, err := parseExtension(extension)
+ if err != nil {
+ return nil, err
+ }
+ oidStr := ext.Id.String()
+ if seenExts[oidStr] {
+ return nil, errors.New("x509: certificate contains duplicate extensions")
+ }
+ seenExts[oidStr] = true
+ cert.Extensions = append(cert.Extensions, ext)
+ }
+ err = processExtensions(cert)
+ if err != nil {
+ return nil, err
+ }
+ }
+ }
+ }
+
+ var signature asn1.BitString
+ if !input.ReadASN1BitString(&signature) {
+ return nil, errors.New("x509: malformed signature")
+ }
+ cert.Signature = signature.RightAlign()
+
+ return cert, nil
+}
+
+// ParseCertificate parses a single certificate from the given ASN.1 DER data.
+func ParseCertificate(der []byte) (*Certificate, error) {
+ cert, err := parseCertificate(der)
+ if err != nil {
+ return nil, err
+ }
+ if len(der) != len(cert.Raw) {
+ return nil, errors.New("x509: trailing data")
+ }
+ return cert, err
+}
+
+// ParseCertificates parses one or more certificates from the given ASN.1 DER
+// data. The certificates must be concatenated with no intermediate padding.
+func ParseCertificates(der []byte) ([]*Certificate, error) {
+ var certs []*Certificate
+ for len(der) > 0 {
+ cert, err := parseCertificate(der)
+ if err != nil {
+ return nil, err
+ }
+ certs = append(certs, cert)
+ der = der[len(cert.Raw):]
+ }
+ return certs, nil
+}
+
+// The X.509 standards confusingly 1-indexed the version names, but 0-indexed
+// the actual encoded version, so the version for X.509v2 is 1.
+const x509v2Version = 1
+
+// ParseRevocationList parses a X509 v2 Certificate Revocation List from the given
+// ASN.1 DER data.
+func ParseRevocationList(der []byte) (*RevocationList, error) {
+ rl := &RevocationList{}
+
+ input := cryptobyte.String(der)
+ // we read the SEQUENCE including length and tag bytes so that
+ // we can populate RevocationList.Raw, before unwrapping the
+ // SEQUENCE so it can be operated on
+ if !input.ReadASN1Element(&input, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed crl")
+ }
+ rl.Raw = input
+ if !input.ReadASN1(&input, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed crl")
+ }
+
+ var tbs cryptobyte.String
+ // do the same trick again as above to extract the raw
+ // bytes for Certificate.RawTBSCertificate
+ if !input.ReadASN1Element(&tbs, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed tbs crl")
+ }
+ rl.RawTBSRevocationList = tbs
+ if !tbs.ReadASN1(&tbs, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed tbs crl")
+ }
+
+ var version int
+ if !tbs.PeekASN1Tag(cryptobyte_asn1.INTEGER) {
+ return nil, errors.New("x509: unsupported crl version")
+ }
+ if !tbs.ReadASN1Integer(&version) {
+ return nil, errors.New("x509: malformed crl")
+ }
+ if version != x509v2Version {
+ return nil, fmt.Errorf("x509: unsupported crl version: %d", version)
+ }
+
+ var sigAISeq cryptobyte.String
+ if !tbs.ReadASN1(&sigAISeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed signature algorithm identifier")
+ }
+ // Before parsing the inner algorithm identifier, extract
+ // the outer algorithm identifier and make sure that they
+ // match.
+ var outerSigAISeq cryptobyte.String
+ if !input.ReadASN1(&outerSigAISeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed algorithm identifier")
+ }
+ if !bytes.Equal(outerSigAISeq, sigAISeq) {
+ return nil, errors.New("x509: inner and outer signature algorithm identifiers don't match")
+ }
+ sigAI, err := parseAI(sigAISeq)
+ if err != nil {
+ return nil, err
+ }
+ rl.SignatureAlgorithm = getSignatureAlgorithmFromAI(sigAI)
+
+ var signature asn1.BitString
+ if !input.ReadASN1BitString(&signature) {
+ return nil, errors.New("x509: malformed signature")
+ }
+ rl.Signature = signature.RightAlign()
+
+ var issuerSeq cryptobyte.String
+ if !tbs.ReadASN1Element(&issuerSeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed issuer")
+ }
+ rl.RawIssuer = issuerSeq
+ issuerRDNs, err := parseName(issuerSeq)
+ if err != nil {
+ return nil, err
+ }
+ rl.Issuer.FillFromRDNSequence(issuerRDNs)
+
+ rl.ThisUpdate, err = parseTime(&tbs)
+ if err != nil {
+ return nil, err
+ }
+ if tbs.PeekASN1Tag(cryptobyte_asn1.GeneralizedTime) || tbs.PeekASN1Tag(cryptobyte_asn1.UTCTime) {
+ rl.NextUpdate, err = parseTime(&tbs)
+ if err != nil {
+ return nil, err
+ }
+ }
+
+ if tbs.PeekASN1Tag(cryptobyte_asn1.SEQUENCE) {
+ var revokedSeq cryptobyte.String
+ if !tbs.ReadASN1(&revokedSeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed crl")
+ }
+ for !revokedSeq.Empty() {
+ rce := RevocationListEntry{}
+
+ var certSeq cryptobyte.String
+ if !revokedSeq.ReadASN1Element(&certSeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed crl")
+ }
+ rce.Raw = certSeq
+ if !certSeq.ReadASN1(&certSeq, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed crl")
+ }
+
+ rce.SerialNumber = new(big.Int)
+ if !certSeq.ReadASN1Integer(rce.SerialNumber) {
+ return nil, errors.New("x509: malformed serial number")
+ }
+ rce.RevocationTime, err = parseTime(&certSeq)
+ if err != nil {
+ return nil, err
+ }
+ var extensions cryptobyte.String
+ var present bool
+ if !certSeq.ReadOptionalASN1(&extensions, &present, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed extensions")
+ }
+ if present {
+ for !extensions.Empty() {
+ var extension cryptobyte.String
+ if !extensions.ReadASN1(&extension, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed extension")
+ }
+ ext, err := parseExtension(extension)
+ if err != nil {
+ return nil, err
+ }
+ if ext.Id.Equal(oidExtensionReasonCode) {
+ val := cryptobyte.String(ext.Value)
+ if !val.ReadASN1Enum(&rce.ReasonCode) {
+ return nil, fmt.Errorf("x509: malformed reasonCode extension")
+ }
+ }
+ rce.Extensions = append(rce.Extensions, ext)
+ }
+ }
+
+ rl.RevokedCertificateEntries = append(rl.RevokedCertificateEntries, rce)
+ rcDeprecated := pkix.RevokedCertificate{
+ SerialNumber: rce.SerialNumber,
+ RevocationTime: rce.RevocationTime,
+ Extensions: rce.Extensions,
+ }
+ rl.RevokedCertificates = append(rl.RevokedCertificates, rcDeprecated)
+ }
+ }
+
+ var extensions cryptobyte.String
+ var present bool
+ if !tbs.ReadOptionalASN1(&extensions, &present, cryptobyte_asn1.Tag(0).Constructed().ContextSpecific()) {
+ return nil, errors.New("x509: malformed extensions")
+ }
+ if present {
+ if !extensions.ReadASN1(&extensions, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed extensions")
+ }
+ for !extensions.Empty() {
+ var extension cryptobyte.String
+ if !extensions.ReadASN1(&extension, cryptobyte_asn1.SEQUENCE) {
+ return nil, errors.New("x509: malformed extension")
+ }
+ ext, err := parseExtension(extension)
+ if err != nil {
+ return nil, err
+ }
+ if ext.Id.Equal(oidExtensionAuthorityKeyId) {
+ rl.AuthorityKeyId = ext.Value
+ } else if ext.Id.Equal(oidExtensionCRLNumber) {
+ value := cryptobyte.String(ext.Value)
+ rl.Number = new(big.Int)
+ if !value.ReadASN1Integer(rl.Number) {
+ return nil, errors.New("x509: malformed crl number")
+ }
+ }
+ rl.Extensions = append(rl.Extensions, ext)
+ }
+ }
+
+ return rl, nil
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-10 05:21:06 +0000