diff options
Diffstat (limited to 'libgo/go/crypto/openpgp/packet/signature.go')
| -rw-r--r-- | libgo/go/crypto/openpgp/packet/signature.go | 558 |
1 files changed, 0 insertions, 558 deletions
diff --git a/libgo/go/crypto/openpgp/packet/signature.go b/libgo/go/crypto/openpgp/packet/signature.go deleted file mode 100644 index 7577e287588..00000000000 --- a/libgo/go/crypto/openpgp/packet/signature.go +++ /dev/null @@ -1,558 +0,0 @@ -// Copyright 2011 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 packet - -import ( - "crypto" - "crypto/dsa" - "crypto/openpgp/error" - "crypto/openpgp/s2k" - "crypto/rand" - "crypto/rsa" - "encoding/binary" - "hash" - "io" - "os" - "strconv" -) - -// Signature represents a signature. See RFC 4880, section 5.2. -type Signature struct { - SigType SignatureType - PubKeyAlgo PublicKeyAlgorithm - Hash crypto.Hash - - // HashSuffix is extra data that is hashed in after the signed data. - HashSuffix []byte - // HashTag contains the first two bytes of the hash for fast rejection - // of bad signed data. - HashTag [2]byte - CreationTime uint32 // Unix epoch time - - RSASignature parsedMPI - DSASigR, DSASigS parsedMPI - - // rawSubpackets contains the unparsed subpackets, in order. - rawSubpackets []outputSubpacket - - // The following are optional so are nil when not included in the - // signature. - - SigLifetimeSecs, KeyLifetimeSecs *uint32 - PreferredSymmetric, PreferredHash, PreferredCompression []uint8 - IssuerKeyId *uint64 - IsPrimaryId *bool - - // FlagsValid is set if any flags were given. See RFC 4880, section - // 5.2.3.21 for details. - FlagsValid bool - FlagCertify, FlagSign, FlagEncryptCommunications, FlagEncryptStorage bool - - outSubpackets []outputSubpacket -} - -func (sig *Signature) parse(r io.Reader) (err os.Error) { - // RFC 4880, section 5.2.3 - var buf [5]byte - _, err = readFull(r, buf[:1]) - if err != nil { - return - } - if buf[0] != 4 { - err = error.UnsupportedError("signature packet version " + strconv.Itoa(int(buf[0]))) - return - } - - _, err = readFull(r, buf[:5]) - if err != nil { - return - } - sig.SigType = SignatureType(buf[0]) - sig.PubKeyAlgo = PublicKeyAlgorithm(buf[1]) - switch sig.PubKeyAlgo { - case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly, PubKeyAlgoDSA: - default: - err = error.UnsupportedError("public key algorithm " + strconv.Itoa(int(sig.PubKeyAlgo))) - return - } - - var ok bool - sig.Hash, ok = s2k.HashIdToHash(buf[2]) - if !ok { - return error.UnsupportedError("hash function " + strconv.Itoa(int(buf[2]))) - } - - hashedSubpacketsLength := int(buf[3])<<8 | int(buf[4]) - l := 6 + hashedSubpacketsLength - sig.HashSuffix = make([]byte, l+6) - sig.HashSuffix[0] = 4 - copy(sig.HashSuffix[1:], buf[:5]) - hashedSubpackets := sig.HashSuffix[6:l] - _, err = readFull(r, hashedSubpackets) - if err != nil { - return - } - // See RFC 4880, section 5.2.4 - trailer := sig.HashSuffix[l:] - trailer[0] = 4 - trailer[1] = 0xff - trailer[2] = uint8(l >> 24) - trailer[3] = uint8(l >> 16) - trailer[4] = uint8(l >> 8) - trailer[5] = uint8(l) - - err = parseSignatureSubpackets(sig, hashedSubpackets, true) - if err != nil { - return - } - - _, err = readFull(r, buf[:2]) - if err != nil { - return - } - unhashedSubpacketsLength := int(buf[0])<<8 | int(buf[1]) - unhashedSubpackets := make([]byte, unhashedSubpacketsLength) - _, err = readFull(r, unhashedSubpackets) - if err != nil { - return - } - err = parseSignatureSubpackets(sig, unhashedSubpackets, false) - if err != nil { - return - } - - _, err = readFull(r, sig.HashTag[:2]) - if err != nil { - return - } - - switch sig.PubKeyAlgo { - case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly: - sig.RSASignature.bytes, sig.RSASignature.bitLength, err = readMPI(r) - case PubKeyAlgoDSA: - sig.DSASigR.bytes, sig.DSASigR.bitLength, err = readMPI(r) - if err == nil { - sig.DSASigS.bytes, sig.DSASigS.bitLength, err = readMPI(r) - } - default: - panic("unreachable") - } - return -} - -// parseSignatureSubpackets parses subpackets of the main signature packet. See -// RFC 4880, section 5.2.3.1. -func parseSignatureSubpackets(sig *Signature, subpackets []byte, isHashed bool) (err os.Error) { - for len(subpackets) > 0 { - subpackets, err = parseSignatureSubpacket(sig, subpackets, isHashed) - if err != nil { - return - } - } - - if sig.CreationTime == 0 { - err = error.StructuralError("no creation time in signature") - } - - return -} - -type signatureSubpacketType uint8 - -const ( - creationTimeSubpacket signatureSubpacketType = 2 - signatureExpirationSubpacket signatureSubpacketType = 3 - keyExpirySubpacket signatureSubpacketType = 9 - prefSymmetricAlgosSubpacket signatureSubpacketType = 11 - issuerSubpacket signatureSubpacketType = 16 - prefHashAlgosSubpacket signatureSubpacketType = 21 - prefCompressionSubpacket signatureSubpacketType = 22 - primaryUserIdSubpacket signatureSubpacketType = 25 - keyFlagsSubpacket signatureSubpacketType = 27 -) - -// parseSignatureSubpacket parses a single subpacket. len(subpacket) is >= 1. -func parseSignatureSubpacket(sig *Signature, subpacket []byte, isHashed bool) (rest []byte, err os.Error) { - // RFC 4880, section 5.2.3.1 - var ( - length uint32 - packetType signatureSubpacketType - isCritical bool - ) - switch { - case subpacket[0] < 192: - length = uint32(subpacket[0]) - subpacket = subpacket[1:] - case subpacket[0] < 255: - if len(subpacket) < 2 { - goto Truncated - } - length = uint32(subpacket[0]-192)<<8 + uint32(subpacket[1]) + 192 - subpacket = subpacket[2:] - default: - if len(subpacket) < 5 { - goto Truncated - } - length = uint32(subpacket[1])<<24 | - uint32(subpacket[2])<<16 | - uint32(subpacket[3])<<8 | - uint32(subpacket[4]) - subpacket = subpacket[5:] - } - if length > uint32(len(subpacket)) { - goto Truncated - } - rest = subpacket[length:] - subpacket = subpacket[:length] - if len(subpacket) == 0 { - err = error.StructuralError("zero length signature subpacket") - return - } - packetType = signatureSubpacketType(subpacket[0] & 0x7f) - isCritical = subpacket[0]&0x80 == 0x80 - subpacket = subpacket[1:] - sig.rawSubpackets = append(sig.rawSubpackets, outputSubpacket{isHashed, packetType, isCritical, subpacket}) - switch packetType { - case creationTimeSubpacket: - if !isHashed { - err = error.StructuralError("signature creation time in non-hashed area") - return - } - if len(subpacket) != 4 { - err = error.StructuralError("signature creation time not four bytes") - return - } - sig.CreationTime = binary.BigEndian.Uint32(subpacket) - case signatureExpirationSubpacket: - // Signature expiration time, section 5.2.3.10 - if !isHashed { - return - } - if len(subpacket) != 4 { - err = error.StructuralError("expiration subpacket with bad length") - return - } - sig.SigLifetimeSecs = new(uint32) - *sig.SigLifetimeSecs = binary.BigEndian.Uint32(subpacket) - case keyExpirySubpacket: - // Key expiration time, section 5.2.3.6 - if !isHashed { - return - } - if len(subpacket) != 4 { - err = error.StructuralError("key expiration subpacket with bad length") - return - } - sig.KeyLifetimeSecs = new(uint32) - *sig.KeyLifetimeSecs = binary.BigEndian.Uint32(subpacket) - case prefSymmetricAlgosSubpacket: - // Preferred symmetric algorithms, section 5.2.3.7 - if !isHashed { - return - } - sig.PreferredSymmetric = make([]byte, len(subpacket)) - copy(sig.PreferredSymmetric, subpacket) - case issuerSubpacket: - // Issuer, section 5.2.3.5 - if len(subpacket) != 8 { - err = error.StructuralError("issuer subpacket with bad length") - return - } - sig.IssuerKeyId = new(uint64) - *sig.IssuerKeyId = binary.BigEndian.Uint64(subpacket) - case prefHashAlgosSubpacket: - // Preferred hash algorithms, section 5.2.3.8 - if !isHashed { - return - } - sig.PreferredHash = make([]byte, len(subpacket)) - copy(sig.PreferredHash, subpacket) - case prefCompressionSubpacket: - // Preferred compression algorithms, section 5.2.3.9 - if !isHashed { - return - } - sig.PreferredCompression = make([]byte, len(subpacket)) - copy(sig.PreferredCompression, subpacket) - case primaryUserIdSubpacket: - // Primary User ID, section 5.2.3.19 - if !isHashed { - return - } - if len(subpacket) != 1 { - err = error.StructuralError("primary user id subpacket with bad length") - return - } - sig.IsPrimaryId = new(bool) - if subpacket[0] > 0 { - *sig.IsPrimaryId = true - } - case keyFlagsSubpacket: - // Key flags, section 5.2.3.21 - if !isHashed { - return - } - if len(subpacket) == 0 { - err = error.StructuralError("empty key flags subpacket") - return - } - sig.FlagsValid = true - if subpacket[0]&1 != 0 { - sig.FlagCertify = true - } - if subpacket[0]&2 != 0 { - sig.FlagSign = true - } - if subpacket[0]&4 != 0 { - sig.FlagEncryptCommunications = true - } - if subpacket[0]&8 != 0 { - sig.FlagEncryptStorage = true - } - - default: - if isCritical { - err = error.UnsupportedError("unknown critical signature subpacket type " + strconv.Itoa(int(packetType))) - return - } - } - return - -Truncated: - err = error.StructuralError("signature subpacket truncated") - return -} - -// subpacketLengthLength returns the length, in bytes, of an encoded length value. -func subpacketLengthLength(length int) int { - if length < 192 { - return 1 - } - if length < 16320 { - return 2 - } - return 5 -} - -// serializeSubpacketLength marshals the given length into to. -func serializeSubpacketLength(to []byte, length int) int { - if length < 192 { - to[0] = byte(length) - return 1 - } - if length < 16320 { - length -= 192 - to[0] = byte(length >> 8) - to[1] = byte(length) - return 2 - } - to[0] = 255 - to[1] = byte(length >> 24) - to[2] = byte(length >> 16) - to[3] = byte(length >> 8) - to[4] = byte(length) - return 5 -} - -// subpacketsLength returns the serialized length, in bytes, of the given -// subpackets. -func subpacketsLength(subpackets []outputSubpacket, hashed bool) (length int) { - for _, subpacket := range subpackets { - if subpacket.hashed == hashed { - length += subpacketLengthLength(len(subpacket.contents) + 1) - length += 1 // type byte - length += len(subpacket.contents) - } - } - return -} - -// serializeSubpackets marshals the given subpackets into to. -func serializeSubpackets(to []byte, subpackets []outputSubpacket, hashed bool) { - for _, subpacket := range subpackets { - if subpacket.hashed == hashed { - n := serializeSubpacketLength(to, len(subpacket.contents)+1) - to[n] = byte(subpacket.subpacketType) - to = to[1+n:] - n = copy(to, subpacket.contents) - to = to[n:] - } - } - return -} - -// buildHashSuffix constructs the HashSuffix member of sig in preparation for signing. -func (sig *Signature) buildHashSuffix() (err os.Error) { - hashedSubpacketsLen := subpacketsLength(sig.outSubpackets, true) - - var ok bool - l := 6 + hashedSubpacketsLen - sig.HashSuffix = make([]byte, l+6) - sig.HashSuffix[0] = 4 - sig.HashSuffix[1] = uint8(sig.SigType) - sig.HashSuffix[2] = uint8(sig.PubKeyAlgo) - sig.HashSuffix[3], ok = s2k.HashToHashId(sig.Hash) - if !ok { - sig.HashSuffix = nil - return error.InvalidArgumentError("hash cannot be represented in OpenPGP: " + strconv.Itoa(int(sig.Hash))) - } - sig.HashSuffix[4] = byte(hashedSubpacketsLen >> 8) - sig.HashSuffix[5] = byte(hashedSubpacketsLen) - serializeSubpackets(sig.HashSuffix[6:l], sig.outSubpackets, true) - trailer := sig.HashSuffix[l:] - trailer[0] = 4 - trailer[1] = 0xff - trailer[2] = byte(l >> 24) - trailer[3] = byte(l >> 16) - trailer[4] = byte(l >> 8) - trailer[5] = byte(l) - return -} - -func (sig *Signature) signPrepareHash(h hash.Hash) (digest []byte, err os.Error) { - err = sig.buildHashSuffix() - if err != nil { - return - } - - h.Write(sig.HashSuffix) - digest = h.Sum() - copy(sig.HashTag[:], digest) - return -} - -// Sign signs a message with a private key. The hash, h, must contain -// the hash of the message to be signed and will be mutated by this function. -// On success, the signature is stored in sig. Call Serialize to write it out. -func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey) (err os.Error) { - sig.outSubpackets = sig.buildSubpackets() - digest, err := sig.signPrepareHash(h) - if err != nil { - return - } - - switch priv.PubKeyAlgo { - case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly: - sig.RSASignature.bytes, err = rsa.SignPKCS1v15(rand.Reader, priv.PrivateKey.(*rsa.PrivateKey), sig.Hash, digest) - sig.RSASignature.bitLength = uint16(8 * len(sig.RSASignature.bytes)) - case PubKeyAlgoDSA: - r, s, err := dsa.Sign(rand.Reader, priv.PrivateKey.(*dsa.PrivateKey), digest) - if err == nil { - sig.DSASigR.bytes = r.Bytes() - sig.DSASigR.bitLength = uint16(8 * len(sig.DSASigR.bytes)) - sig.DSASigS.bytes = s.Bytes() - sig.DSASigS.bitLength = uint16(8 * len(sig.DSASigS.bytes)) - } - default: - err = error.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo))) - } - - return -} - -// SignUserId computes a signature from priv, asserting that pub is a valid -// key for the identity id. On success, the signature is stored in sig. Call -// Serialize to write it out. -func (sig *Signature) SignUserId(id string, pub *PublicKey, priv *PrivateKey) os.Error { - h, err := userIdSignatureHash(id, pub, sig) - if err != nil { - return nil - } - return sig.Sign(h, priv) -} - -// SignKey computes a signature from priv, asserting that pub is a subkey. On -// success, the signature is stored in sig. Call Serialize to write it out. -func (sig *Signature) SignKey(pub *PublicKey, priv *PrivateKey) os.Error { - h, err := keySignatureHash(&priv.PublicKey, pub, sig) - if err != nil { - return err - } - return sig.Sign(h, priv) -} - -// Serialize marshals sig to w. SignRSA or SignDSA must have been called first. -func (sig *Signature) Serialize(w io.Writer) (err os.Error) { - if len(sig.outSubpackets) == 0 { - sig.outSubpackets = sig.rawSubpackets - } - if sig.RSASignature.bytes == nil && sig.DSASigR.bytes == nil { - return error.InvalidArgumentError("Signature: need to call SignRSA or SignDSA before Serialize") - } - - sigLength := 0 - switch sig.PubKeyAlgo { - case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly: - sigLength = 2 + len(sig.RSASignature.bytes) - case PubKeyAlgoDSA: - sigLength = 2 + len(sig.DSASigR.bytes) - sigLength += 2 + len(sig.DSASigS.bytes) - default: - panic("impossible") - } - - unhashedSubpacketsLen := subpacketsLength(sig.outSubpackets, false) - length := len(sig.HashSuffix) - 6 /* trailer not included */ + - 2 /* length of unhashed subpackets */ + unhashedSubpacketsLen + - 2 /* hash tag */ + sigLength - err = serializeHeader(w, packetTypeSignature, length) - if err != nil { - return - } - - _, err = w.Write(sig.HashSuffix[:len(sig.HashSuffix)-6]) - if err != nil { - return - } - - unhashedSubpackets := make([]byte, 2+unhashedSubpacketsLen) - unhashedSubpackets[0] = byte(unhashedSubpacketsLen >> 8) - unhashedSubpackets[1] = byte(unhashedSubpacketsLen) - serializeSubpackets(unhashedSubpackets[2:], sig.outSubpackets, false) - - _, err = w.Write(unhashedSubpackets) - if err != nil { - return - } - _, err = w.Write(sig.HashTag[:]) - if err != nil { - return - } - - switch sig.PubKeyAlgo { - case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly: - err = writeMPIs(w, sig.RSASignature) - case PubKeyAlgoDSA: - err = writeMPIs(w, sig.DSASigR, sig.DSASigS) - default: - panic("impossible") - } - return -} - -// outputSubpacket represents a subpacket to be marshaled. -type outputSubpacket struct { - hashed bool // true if this subpacket is in the hashed area. - subpacketType signatureSubpacketType - isCritical bool - contents []byte -} - -func (sig *Signature) buildSubpackets() (subpackets []outputSubpacket) { - creationTime := make([]byte, 4) - creationTime[0] = byte(sig.CreationTime >> 24) - creationTime[1] = byte(sig.CreationTime >> 16) - creationTime[2] = byte(sig.CreationTime >> 8) - creationTime[3] = byte(sig.CreationTime) - subpackets = append(subpackets, outputSubpacket{true, creationTimeSubpacket, false, creationTime}) - - if sig.IssuerKeyId != nil { - keyId := make([]byte, 8) - binary.BigEndian.PutUint64(keyId, *sig.IssuerKeyId) - subpackets = append(subpackets, outputSubpacket{true, issuerSubpacket, false, keyId}) - } - - return -} |