Ejemplo n.º 1
0
func (pk *PublicKeyV3) parse(r io.Reader) (err error) {
	// RFC 4880, section 5.5.2
	var buf [8]byte
	if _, err = readFull(r, buf[:]); err != nil {
		return
	}
	if buf[0] < 2 || buf[0] > 3 {
		return errors.UnsupportedError("public key version")
	}
	pk.CreationTime = time.Unix(int64(uint32(buf[1])<<24|uint32(buf[2])<<16|uint32(buf[3])<<8|uint32(buf[4])), 0)
	pk.DaysToExpire = binary.BigEndian.Uint16(buf[5:7])
	pk.PubKeyAlgo = PublicKeyAlgorithm(buf[7])
	switch pk.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
		err = pk.parseRSA(r)
	default:
		err = errors.UnsupportedError("public key type: " + strconv.Itoa(int(pk.PubKeyAlgo)))
	}
	if err != nil {
		return
	}

	pk.setFingerPrintAndKeyId()
	return
}
Ejemplo n.º 2
0
func (pk *PrivateKey) parse(r io.Reader) (err error) {
	err = (&pk.PublicKey).parse(r)
	if err != nil {
		return
	}
	var buf [1]byte
	_, err = readFull(r, buf[:])
	if err != nil {
		return
	}

	s2kType := buf[0]

	switch s2kType {
	case 0:
		pk.s2k = nil
		pk.Encrypted = false
	case 254, 255:
		_, err = readFull(r, buf[:])
		if err != nil {
			return
		}
		pk.cipher = CipherFunction(buf[0])
		pk.Encrypted = true
		pk.s2k, err = s2k.Parse(r)
		if err != nil {
			return
		}
		if s2kType == 254 {
			pk.sha1Checksum = true
		}
	default:
		return errors.UnsupportedError("deprecated s2k function in private key")
	}

	if pk.Encrypted {
		blockSize := pk.cipher.blockSize()
		if blockSize == 0 {
			return errors.UnsupportedError("unsupported cipher in private key: " + strconv.Itoa(int(pk.cipher)))
		}
		pk.iv = make([]byte, blockSize)
		_, err = readFull(r, pk.iv)
		if err != nil {
			return
		}
	}

	pk.encryptedData, err = ioutil.ReadAll(r)
	if err != nil {
		return
	}

	if !pk.Encrypted {
		return pk.parsePrivateKey(pk.encryptedData)
	}

	return
}
Ejemplo n.º 3
0
// Encode returns a WriteCloser which will clear-sign a message with privateKey
// and write it to w. If config is nil, sensible defaults are used.
func Encode(w io.Writer, privateKey *packet.PrivateKey, config *packet.Config) (plaintext io.WriteCloser, err error) {
	if privateKey.Encrypted {
		return nil, errors.InvalidArgumentError("signing key is encrypted")
	}

	hashType := config.Hash()
	name := nameOfHash(hashType)
	if len(name) == 0 {
		return nil, errors.UnsupportedError("unknown hash type: " + strconv.Itoa(int(hashType)))
	}

	if !hashType.Available() {
		return nil, errors.UnsupportedError("unsupported hash type: " + strconv.Itoa(int(hashType)))
	}
	h := hashType.New()

	buffered := bufio.NewWriter(w)
	// start has a \n at the beginning that we don't want here.
	if _, err = buffered.Write(start[1:]); err != nil {
		return
	}
	if err = buffered.WriteByte(lf); err != nil {
		return
	}
	if _, err = buffered.WriteString("Hash: "); err != nil {
		return
	}
	if _, err = buffered.WriteString(name); err != nil {
		return
	}
	if err = buffered.WriteByte(lf); err != nil {
		return
	}
	if err = buffered.WriteByte(lf); err != nil {
		return
	}

	plaintext = &dashEscaper{
		buffered: buffered,
		h:        h,
		hashType: hashType,

		atBeginningOfLine: true,
		isFirstLine:       true,

		byteBuf: make([]byte, 1),

		privateKey: privateKey,
		config:     config,
	}

	return
}
Ejemplo n.º 4
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// hashForSignature returns a pair of hashes that can be used to verify a
// signature. The signature may specify that the contents of the signed message
// should be preprocessed (i.e. to normalize line endings). Thus this function
// returns two hashes. The second should be used to hash the message itself and
// performs any needed preprocessing.
func hashForSignature(hashId crypto.Hash, sigType packet.SignatureType) (hash.Hash, hash.Hash, error) {
	if !hashId.Available() {
		return nil, nil, errors.UnsupportedError("hash not available: " + strconv.Itoa(int(hashId)))
	}
	h := hashId.New()

	switch sigType {
	case packet.SigTypeBinary:
		return h, h, nil
	case packet.SigTypeText:
		return h, NewCanonicalTextHash(h), nil
	}

	return nil, nil, errors.UnsupportedError("unsupported signature type: " + strconv.Itoa(int(sigType)))
}
Ejemplo n.º 5
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// parseRSA parses RSA public key material from the given Reader. See RFC 4880,
// section 5.5.2.
func (pk *PublicKeyV3) parseRSA(r io.Reader) (err error) {
	if pk.n.bytes, pk.n.bitLength, err = readMPI(r); err != nil {
		return
	}
	if pk.e.bytes, pk.e.bitLength, err = readMPI(r); err != nil {
		return
	}

	// RFC 4880 Section 12.2 requires the low 8 bytes of the
	// modulus to form the key id.
	if len(pk.n.bytes) < 8 {
		return errors.StructuralError("v3 public key modulus is too short")
	}
	if len(pk.e.bytes) > 3 {
		err = errors.UnsupportedError("large public exponent")
		return
	}
	rsa := &rsa.PublicKey{N: new(big.Int).SetBytes(pk.n.bytes)}
	for i := 0; i < len(pk.e.bytes); i++ {
		rsa.E <<= 8
		rsa.E |= int(pk.e.bytes[i])
	}
	pk.PublicKey = rsa
	return
}
Ejemplo n.º 6
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// parseRSA parses RSA public key material from the given Reader. See RFC 4880,
// section 5.5.2.
func (pk *PublicKey) parseRSA(r io.Reader) (err error) {
	pk.n.bytes, pk.n.bitLength, err = readMPI(r)
	if err != nil {
		return
	}
	pk.e.bytes, pk.e.bitLength, err = readMPI(r)
	if err != nil {
		return
	}

	if len(pk.e.bytes) > 3 {
		err = errors.UnsupportedError("large public exponent")
		return
	}
	rsa := &rsa.PublicKey{
		N: new(big.Int).SetBytes(pk.n.bytes),
		E: 0,
	}
	for i := 0; i < len(pk.e.bytes); i++ {
		rsa.E <<= 8
		rsa.E |= int(pk.e.bytes[i])
	}
	pk.PublicKey = rsa
	return
}
Ejemplo n.º 7
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// SerializeCompressed serializes a compressed data packet to w and
// returns a WriteCloser to which the literal data packets themselves
// can be written and which MUST be closed on completion. If cc is
// nil, sensible defaults will be used to configure the compression
// algorithm.
func SerializeCompressed(w io.WriteCloser, algo CompressionAlgo, cc *CompressionConfig) (literaldata io.WriteCloser, err error) {
	compressed, err := serializeStreamHeader(w, packetTypeCompressed)
	if err != nil {
		return
	}

	_, err = compressed.Write([]byte{uint8(algo)})
	if err != nil {
		return
	}

	level := DefaultCompression
	if cc != nil {
		level = cc.Level
	}

	var compressor io.WriteCloser
	switch algo {
	case CompressionZIP:
		compressor, err = flate.NewWriter(compressed, level)
	case CompressionZLIB:
		compressor, err = zlib.NewWriterLevel(compressed, level)
	default:
		s := strconv.Itoa(int(algo))
		err = errors.UnsupportedError("Unsupported compression algorithm: " + s)
	}
	if err != nil {
		return
	}

	literaldata = compressedWriteCloser{compressed, compressor}

	return
}
Ejemplo n.º 8
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// 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.
// If config is nil, sensible defaults will be used.
func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey, config *Config) (err 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(config.Random(), priv.PrivateKey.(*rsa.PrivateKey), sig.Hash, digest)
		sig.RSASignature.bitLength = uint16(8 * len(sig.RSASignature.bytes))
	case PubKeyAlgoDSA:
		dsaPriv := priv.PrivateKey.(*dsa.PrivateKey)

		// Need to truncate hashBytes to match FIPS 186-3 section 4.6.
		subgroupSize := (dsaPriv.Q.BitLen() + 7) / 8
		if len(digest) > subgroupSize {
			digest = digest[:subgroupSize]
		}
		r, s, err := dsa.Sign(config.Random(), dsaPriv, 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 = errors.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo)))
	}

	return
}
Ejemplo n.º 9
0
func (f *ecdsaKey) newECDSA() (*ecdsa.PublicKey, error) {
	var c elliptic.Curve
	if bytes.Equal(f.oid, oidCurveP256) {
		c = elliptic.P256()
	} else if bytes.Equal(f.oid, oidCurveP384) {
		c = elliptic.P384()
	} else if bytes.Equal(f.oid, oidCurveP521) {
		c = elliptic.P521()
	} else {
		return nil, errors.UnsupportedError(fmt.Sprintf("unsupported oid: %x", f.oid))
	}
	x, y := elliptic.Unmarshal(c, f.p.bytes)
	if x == nil {
		return nil, errors.UnsupportedError("failed to parse EC point")
	}
	return &ecdsa.PublicKey{Curve: c, X: x, Y: y}, nil
}
Ejemplo n.º 10
0
func (pk *PublicKey) parse(r io.Reader) (err error) {
	// RFC 4880, section 5.5.2
	var buf [6]byte
	_, err = readFull(r, buf[:])
	if err != nil {
		return
	}
	if buf[0] != 4 {
		return errors.UnsupportedError("public key version")
	}
	pk.CreationTime = time.Unix(int64(uint32(buf[1])<<24|uint32(buf[2])<<16|uint32(buf[3])<<8|uint32(buf[4])), 0)
	pk.PubKeyAlgo = PublicKeyAlgorithm(buf[5])
	switch pk.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
		err = pk.parseRSA(r)
	case PubKeyAlgoDSA:
		err = pk.parseDSA(r)
	case PubKeyAlgoElGamal:
		err = pk.parseElGamal(r)
	case PubKeyAlgoECDSA:
		pk.ec = new(ecdsaKey)
		if err = pk.ec.parse(r); err != nil {
			return err
		}
		pk.PublicKey, err = pk.ec.newECDSA()
	case PubKeyAlgoECDH:
		pk.ec = new(ecdsaKey)
		if err = pk.ec.parse(r); err != nil {
			return
		}
		pk.ecdh = new(ecdhKdf)
		if err = pk.ecdh.parse(r); err != nil {
			return
		}
		// The ECDH key is stored in an ecdsa.PublicKey for convenience.
		pk.PublicKey, err = pk.ec.newECDSA()
	default:
		err = errors.UnsupportedError("public key type: " + strconv.Itoa(int(pk.PubKeyAlgo)))
	}
	if err != nil {
		return
	}

	pk.setFingerPrintAndKeyId()
	return
}
Ejemplo n.º 11
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// Parse reads a binary specification for a string-to-key transformation from r
// and returns a function which performs that transform.
func Parse(r io.Reader) (f func(out, in []byte), err error) {
	var buf [9]byte

	_, err = io.ReadFull(r, buf[:2])
	if err != nil {
		return
	}

	hash, ok := HashIdToHash(buf[1])
	if !ok {
		return nil, errors.UnsupportedError("hash for S2K function: " + strconv.Itoa(int(buf[1])))
	}
	if !hash.Available() {
		return nil, errors.UnsupportedError("hash not available: " + strconv.Itoa(int(hash)))
	}
	h := hash.New()

	switch buf[0] {
	case 0:
		f := func(out, in []byte) {
			Simple(out, h, in)
		}
		return f, nil
	case 1:
		_, err = io.ReadFull(r, buf[:8])
		if err != nil {
			return
		}
		f := func(out, in []byte) {
			Salted(out, h, in, buf[:8])
		}
		return f, nil
	case 3:
		_, err = io.ReadFull(r, buf[:9])
		if err != nil {
			return
		}
		count := decodeCount(buf[8])
		f := func(out, in []byte) {
			Iterated(out, h, in, buf[:8], count)
		}
		return f, nil
	}

	return nil, errors.UnsupportedError("S2K function")
}
Ejemplo n.º 12
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// SerializeSymmetricKeyEncrypted serializes a symmetric key packet to w. The
// packet contains a random session key, encrypted by a key derived from the
// given passphrase. The session key is returned and must be passed to
// SerializeSymmetricallyEncrypted.
// If config is nil, sensible defaults will be used.
func SerializeSymmetricKeyEncrypted(w io.Writer, passphrase []byte, config *Config) (key []byte, err error) {
	cipherFunc := config.Cipher()
	keySize := cipherFunc.KeySize()
	if keySize == 0 {
		return nil, errors.UnsupportedError("unknown cipher: " + strconv.Itoa(int(cipherFunc)))
	}

	s2kBuf := new(bytes.Buffer)
	keyEncryptingKey := make([]byte, keySize)
	// s2k.Serialize salts and stretches the passphrase, and writes the
	// resulting key to keyEncryptingKey and the s2k descriptor to s2kBuf.
	err = s2k.Serialize(s2kBuf, keyEncryptingKey, config.Random(), passphrase, &s2k.Config{Hash: config.Hash(), S2KCount: config.PasswordHashIterations()})
	if err != nil {
		return
	}
	s2kBytes := s2kBuf.Bytes()

	packetLength := 2 /* header */ + len(s2kBytes) + 1 /* cipher type */ + keySize
	err = serializeHeader(w, packetTypeSymmetricKeyEncrypted, packetLength)
	if err != nil {
		return
	}

	var buf [2]byte
	buf[0] = symmetricKeyEncryptedVersion
	buf[1] = byte(cipherFunc)
	_, err = w.Write(buf[:])
	if err != nil {
		return
	}
	_, err = w.Write(s2kBytes)
	if err != nil {
		return
	}

	sessionKey := make([]byte, keySize)
	_, err = io.ReadFull(config.Random(), sessionKey)
	if err != nil {
		return
	}
	iv := make([]byte, cipherFunc.blockSize())
	c := cipher.NewCFBEncrypter(cipherFunc.new(keyEncryptingKey), iv)
	encryptedCipherAndKey := make([]byte, keySize+1)
	c.XORKeyStream(encryptedCipherAndKey, buf[1:])
	c.XORKeyStream(encryptedCipherAndKey[1:], sessionKey)
	_, err = w.Write(encryptedCipherAndKey)
	if err != nil {
		return
	}

	key = sessionKey
	return
}
Ejemplo n.º 13
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// readSignedMessage reads a possibly signed message if mdin is non-zero then
// that structure is updated and returned. Otherwise a fresh MessageDetails is
// used.
func readSignedMessage(packets *packet.Reader, mdin *MessageDetails, keyring KeyRing) (md *MessageDetails, err error) {
	if mdin == nil {
		mdin = new(MessageDetails)
	}
	md = mdin

	var p packet.Packet
	var h hash.Hash
	var wrappedHash hash.Hash
FindLiteralData:
	for {
		p, err = packets.Next()
		if err != nil {
			return nil, err
		}
		switch p := p.(type) {
		case *packet.Compressed:
			if err := packets.Push(p.Body); err != nil {
				return nil, err
			}
		case *packet.OnePassSignature:
			if !p.IsLast {
				return nil, errors.UnsupportedError("nested signatures")
			}

			h, wrappedHash, err = hashForSignature(p.Hash, p.SigType)
			if err != nil {
				md = nil
				return
			}

			md.IsSigned = true
			md.SignedByKeyId = p.KeyId
			keys := keyring.KeysByIdUsage(p.KeyId, packet.KeyFlagSign)
			if len(keys) > 0 {
				md.SignedBy = &keys[0]
			}
		case *packet.LiteralData:
			md.LiteralData = p
			break FindLiteralData
		}
	}

	if md.SignedBy != nil {
		md.UnverifiedBody = &signatureCheckReader{packets, h, wrappedHash, md}
	} else if md.decrypted != nil {
		md.UnverifiedBody = checkReader{md}
	} else {
		md.UnverifiedBody = md.LiteralData.Body
	}

	return md, nil
}
Ejemplo n.º 14
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func keyRevocationHash(pk signingKey, hashFunc crypto.Hash) (h hash.Hash, err error) {
	if !hashFunc.Available() {
		return nil, errors.UnsupportedError("hash function")
	}
	h = hashFunc.New()

	// RFC 4880, section 5.2.4
	pk.SerializeSignaturePrefix(h)
	pk.serializeWithoutHeaders(h)

	return
}
Ejemplo n.º 15
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func (f *ecdhKdf) parse(r io.Reader) (err error) {
	buf := make([]byte, 1)
	if _, err = readFull(r, buf); err != nil {
		return
	}
	kdfLen := int(buf[0])
	if kdfLen < 3 {
		return errors.UnsupportedError("Unsupported ECDH KDF length: " + strconv.Itoa(kdfLen))
	}
	buf = make([]byte, kdfLen)
	if _, err = readFull(r, buf); err != nil {
		return
	}
	reserved := int(buf[0])
	f.KdfHash = kdfHashFunction(buf[1])
	f.KdfAlgo = kdfAlgorithm(buf[2])
	if reserved != 0x01 {
		return errors.UnsupportedError("Unsupported KDF reserved field: " + strconv.Itoa(reserved))
	}
	return
}
Ejemplo n.º 16
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func (ske *SymmetricKeyEncrypted) parse(r io.Reader) error {
	// RFC 4880, section 5.3.
	var buf [2]byte
	if _, err := readFull(r, buf[:]); err != nil {
		return err
	}
	if buf[0] != symmetricKeyEncryptedVersion {
		return errors.UnsupportedError("SymmetricKeyEncrypted version")
	}
	ske.CipherFunc = CipherFunction(buf[1])

	if ske.CipherFunc.KeySize() == 0 {
		return errors.UnsupportedError("unknown cipher: " + strconv.Itoa(int(buf[1])))
	}

	var err error
	ske.s2k, err = s2k.Parse(r)
	if err != nil {
		return err
	}

	encryptedKey := make([]byte, maxSessionKeySizeInBytes)
	// The session key may follow. We just have to try and read to find
	// out. If it exists then we limit it to maxSessionKeySizeInBytes.
	n, err := readFull(r, encryptedKey)
	if err != nil && err != io.ErrUnexpectedEOF {
		return err
	}

	if n != 0 {
		if n == maxSessionKeySizeInBytes {
			return errors.UnsupportedError("oversized encrypted session key")
		}
		ske.encryptedKey = encryptedKey[:n]
	}

	return nil
}
Ejemplo n.º 17
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// parseOID reads the OID for the curve as defined in RFC 6637, Section 9.
func parseOID(r io.Reader) (oid []byte, err error) {
	buf := make([]byte, maxOIDLength)
	if _, err = readFull(r, buf[:1]); err != nil {
		return
	}
	oidLen := buf[0]
	if int(oidLen) > len(buf) {
		err = errors.UnsupportedError("invalid oid length: " + strconv.Itoa(int(oidLen)))
		return
	}
	oid = buf[:oidLen]
	_, err = readFull(r, oid)
	return
}
Ejemplo n.º 18
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func (ops *OnePassSignature) parse(r io.Reader) (err error) {
	var buf [13]byte

	_, err = readFull(r, buf[:])
	if err != nil {
		return
	}
	if buf[0] != onePassSignatureVersion {
		err = errors.UnsupportedError("one-pass-signature packet version " + strconv.Itoa(int(buf[0])))
	}

	var ok bool
	ops.Hash, ok = s2k.HashIdToHash(buf[2])
	if !ok {
		return errors.UnsupportedError("hash function: " + strconv.Itoa(int(buf[2])))
	}

	ops.SigType = SignatureType(buf[1])
	ops.PubKeyAlgo = PublicKeyAlgorithm(buf[3])
	ops.KeyId = binary.BigEndian.Uint64(buf[4:12])
	ops.IsLast = buf[12] != 0
	return
}
Ejemplo n.º 19
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// userIdSignatureV3Hash returns a Hash of the message that needs to be signed
// to assert that pk is a valid key for id.
func userIdSignatureV3Hash(id string, pk signingKey, hfn crypto.Hash) (h hash.Hash, err error) {
	if !hfn.Available() {
		return nil, errors.UnsupportedError("hash function")
	}
	h = hfn.New()

	// RFC 4880, section 5.2.4
	pk.SerializeSignaturePrefix(h)
	pk.serializeWithoutHeaders(h)

	h.Write([]byte(id))

	return
}
Ejemplo n.º 20
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func (se *SymmetricallyEncrypted) parse(r io.Reader) error {
	if se.MDC {
		// See RFC 4880, section 5.13.
		var buf [1]byte
		_, err := readFull(r, buf[:])
		if err != nil {
			return err
		}
		if buf[0] != symmetricallyEncryptedVersion {
			return errors.UnsupportedError("unknown SymmetricallyEncrypted version")
		}
	}
	se.contents = r
	return nil
}
Ejemplo n.º 21
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// Serialize marshals sig to w. Sign, SignUserId or SignKey must have been
// called first.
func (sig *SignatureV3) Serialize(w io.Writer) (err error) {
	buf := make([]byte, 8)

	// Write the sig type and creation time
	buf[0] = byte(sig.SigType)
	binary.BigEndian.PutUint32(buf[1:5], uint32(sig.CreationTime.Unix()))
	if _, err = w.Write(buf[:5]); err != nil {
		return
	}

	// Write the issuer long key ID
	binary.BigEndian.PutUint64(buf[:8], sig.IssuerKeyId)
	if _, err = w.Write(buf[:8]); err != nil {
		return
	}

	// Write public key algorithm, hash ID, and hash value
	buf[0] = byte(sig.PubKeyAlgo)
	hashId, ok := s2k.HashToHashId(sig.Hash)
	if !ok {
		return errors.UnsupportedError(fmt.Sprintf("hash function %v", sig.Hash))
	}
	buf[1] = hashId
	copy(buf[2:4], sig.HashTag[:])
	if _, err = w.Write(buf[:4]); err != nil {
		return
	}

	if sig.RSASignature.bytes == nil && sig.DSASigR.bytes == nil {
		return errors.InvalidArgumentError("Signature: need to call Sign, SignUserId or SignKey before Serialize")
	}

	switch sig.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
		err = writeMPIs(w, sig.RSASignature)
	case PubKeyAlgoDSA:
		err = writeMPIs(w, sig.DSASigR, sig.DSASigS)
	default:
		panic("impossible")
	}
	return
}
Ejemplo n.º 22
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// Decrypt returns a ReadCloser, from which the decrypted contents of the
// packet can be read. An incorrect key can, with high probability, be detected
// immediately and this will result in a KeyIncorrect error being returned.
func (se *SymmetricallyEncrypted) Decrypt(c CipherFunction, key []byte) (io.ReadCloser, error) {
	keySize := c.KeySize()
	if keySize == 0 {
		return nil, errors.UnsupportedError("unknown cipher: " + strconv.Itoa(int(c)))
	}
	if len(key) != keySize {
		return nil, errors.InvalidArgumentError("SymmetricallyEncrypted: incorrect key length")
	}

	if se.prefix == nil {
		se.prefix = make([]byte, c.blockSize()+2)
		_, err := readFull(se.contents, se.prefix)
		if err != nil {
			return nil, err
		}
	} else if len(se.prefix) != c.blockSize()+2 {
		return nil, errors.InvalidArgumentError("can't try ciphers with different block lengths")
	}

	ocfbResync := OCFBResync
	if se.MDC {
		// MDC packets use a different form of OCFB mode.
		ocfbResync = OCFBNoResync
	}

	s := NewOCFBDecrypter(c.new(key), se.prefix, ocfbResync)
	if s == nil {
		return nil, errors.ErrKeyIncorrect
	}

	plaintext := cipher.StreamReader{S: s, R: se.contents}

	if se.MDC {
		// MDC packets have an embedded hash that we need to check.
		h := sha1.New()
		h.Write(se.prefix)
		return &seMDCReader{in: plaintext, h: h}, nil
	}

	// Otherwise, we just need to wrap plaintext so that it's a valid ReadCloser.
	return seReader{plaintext}, nil
}
Ejemplo n.º 23
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func (c *Compressed) parse(r io.Reader) error {
	var buf [1]byte
	_, err := readFull(r, buf[:])
	if err != nil {
		return err
	}

	switch buf[0] {
	case 1:
		c.Body = flate.NewReader(r)
	case 2:
		c.Body, err = zlib.NewReader(r)
	case 3:
		c.Body = bzip2.NewReader(r)
	default:
		err = errors.UnsupportedError("unknown compression algorithm: " + strconv.Itoa(int(buf[0])))
	}

	return err
}
Ejemplo n.º 24
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// Serialize marshals the given OnePassSignature to w.
func (ops *OnePassSignature) Serialize(w io.Writer) error {
	var buf [13]byte
	buf[0] = onePassSignatureVersion
	buf[1] = uint8(ops.SigType)
	var ok bool
	buf[2], ok = s2k.HashToHashId(ops.Hash)
	if !ok {
		return errors.UnsupportedError("hash type: " + strconv.Itoa(int(ops.Hash)))
	}
	buf[3] = uint8(ops.PubKeyAlgo)
	binary.BigEndian.PutUint64(buf[4:12], ops.KeyId)
	if ops.IsLast {
		buf[12] = 1
	}

	if err := serializeHeader(w, packetTypeOnePassSignature, len(buf)); err != nil {
		return err
	}
	_, err := w.Write(buf[:])
	return err
}
Ejemplo n.º 25
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// userIdSignatureHash returns a Hash of the message that needs to be signed
// to assert that pk is a valid key for id.
func userIdSignatureHash(id string, pk *PublicKey, hashFunc crypto.Hash) (h hash.Hash, err error) {
	if !hashFunc.Available() {
		return nil, errors.UnsupportedError("hash function")
	}
	h = hashFunc.New()

	// RFC 4880, section 5.2.4
	pk.SerializeSignaturePrefix(h)
	pk.serializeWithoutHeaders(h)

	var buf [5]byte
	buf[0] = 0xb4
	buf[1] = byte(len(id) >> 24)
	buf[2] = byte(len(id) >> 16)
	buf[3] = byte(len(id) >> 8)
	buf[4] = byte(len(id))
	h.Write(buf[:])
	h.Write([]byte(id))

	return
}
Ejemplo n.º 26
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// SerializeEncryptedKey serializes an encrypted key packet to w that contains
// key, encrypted to pub.
// If config is nil, sensible defaults will be used.
func SerializeEncryptedKey(w io.Writer, pub *PublicKey, cipherFunc CipherFunction, key []byte, config *Config) error {
	var buf [10]byte
	buf[0] = encryptedKeyVersion
	binary.BigEndian.PutUint64(buf[1:9], pub.KeyId)
	buf[9] = byte(pub.PubKeyAlgo)

	keyBlock := make([]byte, 1 /* cipher type */ +len(key)+2 /* checksum */)
	keyBlock[0] = byte(cipherFunc)
	copy(keyBlock[1:], key)
	checksum := checksumKeyMaterial(key)
	keyBlock[1+len(key)] = byte(checksum >> 8)
	keyBlock[1+len(key)+1] = byte(checksum)

	switch pub.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
		return serializeEncryptedKeyRSA(w, config.Random(), buf, pub.PublicKey.(*rsa.PublicKey), keyBlock)
	case PubKeyAlgoElGamal:
		return serializeEncryptedKeyElGamal(w, config.Random(), buf, pub.PublicKey.(*elgamal.PublicKey), keyBlock)
	case PubKeyAlgoDSA, PubKeyAlgoRSASignOnly:
		return errors.InvalidArgumentError("cannot encrypt to public key of type " + strconv.Itoa(int(pub.PubKeyAlgo)))
	}

	return errors.UnsupportedError("encrypting a key to public key of type " + strconv.Itoa(int(pub.PubKeyAlgo)))
}
Ejemplo n.º 27
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func (e *EncryptedKey) parse(r io.Reader) (err error) {
	var buf [10]byte
	_, err = readFull(r, buf[:])
	if err != nil {
		return
	}
	if buf[0] != encryptedKeyVersion {
		return errors.UnsupportedError("unknown EncryptedKey version " + strconv.Itoa(int(buf[0])))
	}
	e.KeyId = binary.BigEndian.Uint64(buf[1:9])
	e.Algo = PublicKeyAlgorithm(buf[9])
	switch e.Algo {
	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
		e.encryptedMPI1.bytes, e.encryptedMPI1.bitLength, err = readMPI(r)
	case PubKeyAlgoElGamal:
		e.encryptedMPI1.bytes, e.encryptedMPI1.bitLength, err = readMPI(r)
		if err != nil {
			return
		}
		e.encryptedMPI2.bytes, e.encryptedMPI2.bitLength, err = readMPI(r)
	}
	_, err = consumeAll(r)
	return
}
Ejemplo n.º 28
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// Decrypt attempts to decrypt an encrypted session key and returns the key and
// the cipher to use when decrypting a subsequent Symmetrically Encrypted Data
// packet.
func (ske *SymmetricKeyEncrypted) Decrypt(passphrase []byte) ([]byte, CipherFunction, error) {
	key := make([]byte, ske.CipherFunc.KeySize())
	ske.s2k(key, passphrase)

	if len(ske.encryptedKey) == 0 {
		return key, ske.CipherFunc, nil
	}

	// the IV is all zeros
	iv := make([]byte, ske.CipherFunc.blockSize())
	c := cipher.NewCFBDecrypter(ske.CipherFunc.new(key), iv)
	plaintextKey := make([]byte, len(ske.encryptedKey))
	c.XORKeyStream(plaintextKey, ske.encryptedKey)
	cipherFunc := CipherFunction(plaintextKey[0])
	if cipherFunc.blockSize() == 0 {
		return nil, ske.CipherFunc, errors.UnsupportedError("unknown cipher: " + strconv.Itoa(int(cipherFunc)))
	}
	plaintextKey = plaintextKey[1:]
	if l := len(plaintextKey); l == 0 || l%cipherFunc.blockSize() != 0 {
		return nil, cipherFunc, errors.StructuralError("length of decrypted key not a multiple of block size")
	}

	return plaintextKey, cipherFunc, nil
}
Ejemplo n.º 29
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func (sig *SignatureV3) parse(r io.Reader) (err error) {
	// RFC 4880, section 5.2.2
	var buf [8]byte
	if _, err = readFull(r, buf[:1]); err != nil {
		return
	}
	if buf[0] < 2 || buf[0] > 3 {
		err = errors.UnsupportedError("signature packet version " + strconv.Itoa(int(buf[0])))
		return
	}
	if _, err = readFull(r, buf[:1]); err != nil {
		return
	}
	if buf[0] != 5 {
		err = errors.UnsupportedError(
			"invalid hashed material length " + strconv.Itoa(int(buf[0])))
		return
	}

	// Read hashed material: signature type + creation time
	if _, err = readFull(r, buf[:5]); err != nil {
		return
	}
	sig.SigType = SignatureType(buf[0])
	t := binary.BigEndian.Uint32(buf[1:5])
	sig.CreationTime = time.Unix(int64(t), 0)

	// Eight-octet Key ID of signer.
	if _, err = readFull(r, buf[:8]); err != nil {
		return
	}
	sig.IssuerKeyId = binary.BigEndian.Uint64(buf[:])

	// Public-key and hash algorithm
	if _, err = readFull(r, buf[:2]); err != nil {
		return
	}
	sig.PubKeyAlgo = PublicKeyAlgorithm(buf[0])
	switch sig.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly, PubKeyAlgoDSA:
	default:
		err = errors.UnsupportedError("public key algorithm " + strconv.Itoa(int(sig.PubKeyAlgo)))
		return
	}
	var ok bool
	if sig.Hash, ok = s2k.HashIdToHash(buf[1]); !ok {
		return errors.UnsupportedError("hash function " + strconv.Itoa(int(buf[2])))
	}

	// Two-octet field holding left 16 bits of signed hash value.
	if _, err = readFull(r, sig.HashTag[:2]); err != nil {
		return
	}

	switch sig.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
		sig.RSASignature.bytes, sig.RSASignature.bitLength, err = readMPI(r)
	case PubKeyAlgoDSA:
		if sig.DSASigR.bytes, sig.DSASigR.bitLength, err = readMPI(r); err != nil {
			return
		}
		sig.DSASigS.bytes, sig.DSASigS.bitLength, err = readMPI(r)
	default:
		panic("unreachable")
	}
	return
}
Ejemplo n.º 30
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func (sig *Signature) parse(r io.Reader) (err 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 = errors.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, PubKeyAlgoECDSA:
	default:
		err = errors.UnsupportedError("public key algorithm " + strconv.Itoa(int(sig.PubKeyAlgo)))
		return
	}

	var ok bool
	sig.Hash, ok = s2k.HashIdToHash(buf[2])
	if !ok {
		return errors.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)
		}
	case PubKeyAlgoECDSA:
		sig.ECDSASigR.bytes, sig.ECDSASigR.bitLength, err = readMPI(r)
		if err == nil {
			sig.ECDSASigS.bytes, sig.ECDSASigS.bitLength, err = readMPI(r)
		}
	default:
		panic("unreachable")
	}
	return
}