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Switch to keybase go-crypto (for some elliptic curve key) + test (#1925)

* Switch to keybase go-crypto (for some elliptic curve key) + test

* Use assert.NoError 

and add a little more context to failing test description

* Use assert.(No)Error everywhere 🌈

and assert.Error in place of .Nil/.NotNil
This commit is contained in:
Antoine GIRARD 2017-06-14 02:43:43 +02:00 committed by Lunny Xiao
parent 5e92b82ac6
commit 274149dd14
56 changed files with 10621 additions and 925 deletions

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// 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 (
"compress/bzip2"
"compress/flate"
"compress/zlib"
"io"
"strconv"
"github.com/keybase/go-crypto/openpgp/errors"
)
// Compressed represents a compressed OpenPGP packet. The decompressed contents
// will contain more OpenPGP packets. See RFC 4880, section 5.6.
type Compressed struct {
Body io.Reader
}
const (
NoCompression = flate.NoCompression
BestSpeed = flate.BestSpeed
BestCompression = flate.BestCompression
DefaultCompression = flate.DefaultCompression
)
// CompressionConfig contains compressor configuration settings.
type CompressionConfig struct {
// Level is the compression level to use. It must be set to
// between -1 and 9, with -1 causing the compressor to use the
// default compression level, 0 causing the compressor to use
// no compression and 1 to 9 representing increasing (better,
// slower) compression levels. If Level is less than -1 or
// more then 9, a non-nil error will be returned during
// encryption. See the constants above for convenient common
// settings for Level.
Level int
}
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
}
// compressedWriterCloser represents the serialized compression stream
// header and the compressor. Its Close() method ensures that both the
// compressor and serialized stream header are closed. Its Write()
// method writes to the compressor.
type compressedWriteCloser struct {
sh io.Closer // Stream Header
c io.WriteCloser // Compressor
}
func (cwc compressedWriteCloser) Write(p []byte) (int, error) {
return cwc.c.Write(p)
}
func (cwc compressedWriteCloser) Close() (err error) {
err = cwc.c.Close()
if err != nil {
return err
}
return cwc.sh.Close()
}
// 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
}

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// Copyright 2012 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/rand"
"io"
"time"
)
// Config collects a number of parameters along with sensible defaults.
// A nil *Config is valid and results in all default values.
type Config struct {
// Rand provides the source of entropy.
// If nil, the crypto/rand Reader is used.
Rand io.Reader
// DefaultHash is the default hash function to be used.
// If zero, SHA-256 is used.
DefaultHash crypto.Hash
// DefaultCipher is the cipher to be used.
// If zero, AES-128 is used.
DefaultCipher CipherFunction
// Time returns the current time as the number of seconds since the
// epoch. If Time is nil, time.Now is used.
Time func() time.Time
// DefaultCompressionAlgo is the compression algorithm to be
// applied to the plaintext before encryption. If zero, no
// compression is done.
DefaultCompressionAlgo CompressionAlgo
// CompressionConfig configures the compression settings.
CompressionConfig *CompressionConfig
// S2KCount is only used for symmetric encryption. It
// determines the strength of the passphrase stretching when
// the said passphrase is hashed to produce a key. S2KCount
// should be between 1024 and 65011712, inclusive. If Config
// is nil or S2KCount is 0, the value 65536 used. Not all
// values in the above range can be represented. S2KCount will
// be rounded up to the next representable value if it cannot
// be encoded exactly. When set, it is strongly encrouraged to
// use a value that is at least 65536. See RFC 4880 Section
// 3.7.1.3.
S2KCount int
// RSABits is the number of bits in new RSA keys made with NewEntity.
// If zero, then 2048 bit keys are created.
RSABits int
// ReuseSignatures tells us to reuse existing Signatures
// on serialized output.
ReuseSignaturesOnSerialize bool
}
func (c *Config) Random() io.Reader {
if c == nil || c.Rand == nil {
return rand.Reader
}
return c.Rand
}
func (c *Config) Hash() crypto.Hash {
if c == nil || uint(c.DefaultHash) == 0 {
return crypto.SHA256
}
return c.DefaultHash
}
func (c *Config) Cipher() CipherFunction {
if c == nil || uint8(c.DefaultCipher) == 0 {
return CipherAES128
}
return c.DefaultCipher
}
func (c *Config) Now() time.Time {
if c == nil || c.Time == nil {
return time.Now()
}
return c.Time()
}
func (c *Config) Compression() CompressionAlgo {
if c == nil {
return CompressionNone
}
return c.DefaultCompressionAlgo
}
func (c *Config) PasswordHashIterations() int {
if c == nil || c.S2KCount == 0 {
return 0
}
return c.S2KCount
}
func (c *Config) ReuseSignatures() bool {
return c != nil && c.ReuseSignaturesOnSerialize
}

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package packet
import (
"bytes"
"io"
"math/big"
"github.com/keybase/go-crypto/openpgp/ecdh"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/openpgp/s2k"
)
// ECDHKdfParams generates KDF parameters sequence for given
// PublicKey. See https://tools.ietf.org/html/rfc6637#section-8
func ECDHKdfParams(pub *PublicKey) []byte {
buf := new(bytes.Buffer)
oid := pub.ec.oid
buf.WriteByte(byte(len(oid)))
buf.Write(oid)
buf.WriteByte(18) // ECDH TYPE
pub.ecdh.serialize(buf)
buf.WriteString("Anonymous Sender ")
buf.Write(pub.Fingerprint[:])
return buf.Bytes()
}
func decryptKeyECDH(priv *PrivateKey, X, Y *big.Int, C []byte) (out []byte, err error) {
ecdhpriv, ok := priv.PrivateKey.(*ecdh.PrivateKey)
if !ok {
return nil, errors.InvalidArgumentError("bad internal ECDH key")
}
Sx := ecdhpriv.DecryptShared(X, Y)
kdfParams := ECDHKdfParams(&priv.PublicKey)
hash, ok := s2k.HashIdToHash(byte(priv.ecdh.KdfHash))
if !ok {
return nil, errors.InvalidArgumentError("invalid hash id in private key")
}
key := ecdhpriv.KDF(Sx, kdfParams, hash)
keySize := CipherFunction(priv.ecdh.KdfAlgo).KeySize()
decrypted, err := ecdh.AESKeyUnwrap(key[:keySize], C)
if err != nil {
return nil, err
}
// We have to "read ahead" to discover real length of the
// encryption key and properly unpad buffer.
cipherFunc := CipherFunction(decrypted[0])
// +3 bytes = 1-byte cipher id and checksum 2-byte checksum.
out = ecdh.UnpadBuffer(decrypted, cipherFunc.KeySize()+3)
if out == nil {
return nil, errors.InvalidArgumentError("invalid padding while ECDH")
}
return out, nil
}
func serializeEncryptedKeyECDH(w io.Writer, rand io.Reader, header [10]byte, pub *PublicKey, keyBlock []byte) error {
ecdhpub := pub.PublicKey.(*ecdh.PublicKey)
kdfParams := ECDHKdfParams(pub)
hash, ok := s2k.HashIdToHash(byte(pub.ecdh.KdfHash))
if !ok {
return errors.InvalidArgumentError("invalid hash id in private key")
}
kdfKeySize := CipherFunction(pub.ecdh.KdfAlgo).KeySize()
Vx, Vy, C, err := ecdhpub.Encrypt(rand, kdfParams, keyBlock, hash, kdfKeySize)
if err != nil {
return err
}
mpis, mpiBitLen := ecdh.Marshal(ecdhpub.Curve, Vx, Vy)
packetLen := len(header) /* header length in bytes */
packetLen += 2 /* mpi length in bits */ + len(mpis)
packetLen += 1 /* ciphertext size in bytes */ + len(C)
err = serializeHeader(w, packetTypeEncryptedKey, packetLen)
if err != nil {
return err
}
_, err = w.Write(header[:])
if err != nil {
return err
}
_, err = w.Write([]byte{byte(mpiBitLen >> 8), byte(mpiBitLen)})
if err != nil {
return err
}
_, err = w.Write(mpis[:])
if err != nil {
return err
}
w.Write([]byte{byte(len(C))})
w.Write(C[:])
return nil
}

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// 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 (
"encoding/binary"
"io"
"math/big"
"strconv"
"github.com/keybase/go-crypto/openpgp/ecdh"
"github.com/keybase/go-crypto/openpgp/elgamal"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/rsa"
)
const encryptedKeyVersion = 3
// EncryptedKey represents a public-key encrypted session key. See RFC 4880,
// section 5.1.
type EncryptedKey struct {
KeyId uint64
Algo PublicKeyAlgorithm
CipherFunc CipherFunction // only valid after a successful Decrypt
Key []byte // only valid after a successful Decrypt
encryptedMPI1, encryptedMPI2 parsedMPI
ecdh_C []byte
}
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)
case PubKeyAlgoECDH:
e.encryptedMPI1.bytes, e.encryptedMPI1.bitLength, err = readMPI(r)
if err != nil {
return err
}
_, err = readFull(r, buf[:1]) // read C len (1 byte)
if err != nil {
return err
}
e.ecdh_C = make([]byte, int(buf[0]))
_, err = readFull(r, e.ecdh_C)
}
if err != nil {
return err
}
_, err = consumeAll(r)
return err
}
func checksumKeyMaterial(key []byte) uint16 {
var checksum uint16
for _, v := range key {
checksum += uint16(v)
}
return checksum
}
// Decrypt decrypts an encrypted session key with the given private key. The
// private key must have been decrypted first.
// If config is nil, sensible defaults will be used.
func (e *EncryptedKey) Decrypt(priv *PrivateKey, config *Config) error {
var err error
var b []byte
// TODO(agl): use session key decryption routines here to avoid
// padding oracle attacks.
switch priv.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
b, err = rsa.DecryptPKCS1v15(config.Random(), priv.PrivateKey.(*rsa.PrivateKey), e.encryptedMPI1.bytes)
case PubKeyAlgoElGamal:
c1 := new(big.Int).SetBytes(e.encryptedMPI1.bytes)
c2 := new(big.Int).SetBytes(e.encryptedMPI2.bytes)
b, err = elgamal.Decrypt(priv.PrivateKey.(*elgamal.PrivateKey), c1, c2)
case PubKeyAlgoECDH:
// Note: Unmarshal checks if point is on the curve.
c1, c2 := ecdh.Unmarshal(priv.PrivateKey.(*ecdh.PrivateKey).Curve, e.encryptedMPI1.bytes)
if c1 == nil {
return errors.InvalidArgumentError("failed to parse EC point for encryption key")
}
b, err = decryptKeyECDH(priv, c1, c2, e.ecdh_C)
default:
err = errors.InvalidArgumentError("cannot decrypted encrypted session key with private key of type " + strconv.Itoa(int(priv.PubKeyAlgo)))
}
if err != nil {
return err
}
e.CipherFunc = CipherFunction(b[0])
e.Key = b[1 : len(b)-2]
expectedChecksum := uint16(b[len(b)-2])<<8 | uint16(b[len(b)-1])
checksum := checksumKeyMaterial(e.Key)
if checksum != expectedChecksum {
return errors.StructuralError("EncryptedKey checksum incorrect")
}
return nil
}
// Serialize writes the encrypted key packet, e, to w.
func (e *EncryptedKey) Serialize(w io.Writer) error {
var mpiLen int
switch e.Algo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
mpiLen = 2 + len(e.encryptedMPI1.bytes)
case PubKeyAlgoElGamal:
mpiLen = 2 + len(e.encryptedMPI1.bytes) + 2 + len(e.encryptedMPI2.bytes)
default:
return errors.InvalidArgumentError("don't know how to serialize encrypted key type " + strconv.Itoa(int(e.Algo)))
}
serializeHeader(w, packetTypeEncryptedKey, 1 /* version */ +8 /* key id */ +1 /* algo */ +mpiLen)
w.Write([]byte{encryptedKeyVersion})
binary.Write(w, binary.BigEndian, e.KeyId)
w.Write([]byte{byte(e.Algo)})
switch e.Algo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
writeMPIs(w, e.encryptedMPI1)
case PubKeyAlgoElGamal:
writeMPIs(w, e.encryptedMPI1, e.encryptedMPI2)
default:
panic("internal error")
}
return nil
}
// 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 PubKeyAlgoECDH:
return serializeEncryptedKeyECDH(w, config.Random(), buf, pub, 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)))
}
func serializeEncryptedKeyRSA(w io.Writer, rand io.Reader, header [10]byte, pub *rsa.PublicKey, keyBlock []byte) error {
cipherText, err := rsa.EncryptPKCS1v15(rand, pub, keyBlock)
if err != nil {
return errors.InvalidArgumentError("RSA encryption failed: " + err.Error())
}
packetLen := 10 /* header length */ + 2 /* mpi size */ + len(cipherText)
err = serializeHeader(w, packetTypeEncryptedKey, packetLen)
if err != nil {
return err
}
_, err = w.Write(header[:])
if err != nil {
return err
}
return writeMPI(w, 8*uint16(len(cipherText)), cipherText)
}
func serializeEncryptedKeyElGamal(w io.Writer, rand io.Reader, header [10]byte, pub *elgamal.PublicKey, keyBlock []byte) error {
c1, c2, err := elgamal.Encrypt(rand, pub, keyBlock)
if err != nil {
return errors.InvalidArgumentError("ElGamal encryption failed: " + err.Error())
}
packetLen := 10 /* header length */
packetLen += 2 /* mpi size */ + (c1.BitLen()+7)/8
packetLen += 2 /* mpi size */ + (c2.BitLen()+7)/8
err = serializeHeader(w, packetTypeEncryptedKey, packetLen)
if err != nil {
return err
}
_, err = w.Write(header[:])
if err != nil {
return err
}
err = writeBig(w, c1)
if err != nil {
return err
}
return writeBig(w, c2)
}

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// 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 (
"encoding/binary"
"io"
)
// LiteralData represents an encrypted file. See RFC 4880, section 5.9.
type LiteralData struct {
IsBinary bool
FileName string
Time uint32 // Unix epoch time. Either creation time or modification time. 0 means undefined.
Body io.Reader
}
// ForEyesOnly returns whether the contents of the LiteralData have been marked
// as especially sensitive.
func (l *LiteralData) ForEyesOnly() bool {
return l.FileName == "_CONSOLE"
}
func (l *LiteralData) parse(r io.Reader) (err error) {
var buf [256]byte
_, err = readFull(r, buf[:2])
if err != nil {
return
}
l.IsBinary = buf[0] == 'b'
fileNameLen := int(buf[1])
_, err = readFull(r, buf[:fileNameLen])
if err != nil {
return
}
l.FileName = string(buf[:fileNameLen])
_, err = readFull(r, buf[:4])
if err != nil {
return
}
l.Time = binary.BigEndian.Uint32(buf[:4])
l.Body = r
return
}
// SerializeLiteral serializes a literal data packet to w and returns a
// WriteCloser to which the data itself can be written and which MUST be closed
// on completion. The fileName is truncated to 255 bytes.
func SerializeLiteral(w io.WriteCloser, isBinary bool, fileName string, time uint32) (plaintext io.WriteCloser, err error) {
var buf [4]byte
buf[0] = 't'
if isBinary {
buf[0] = 'b'
}
if len(fileName) > 255 {
fileName = fileName[:255]
}
buf[1] = byte(len(fileName))
inner, err := serializeStreamHeader(w, packetTypeLiteralData)
if err != nil {
return
}
_, err = inner.Write(buf[:2])
if err != nil {
return
}
_, err = inner.Write([]byte(fileName))
if err != nil {
return
}
binary.BigEndian.PutUint32(buf[:], time)
_, err = inner.Write(buf[:])
if err != nil {
return
}
plaintext = inner
return
}

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// Copyright 2010 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.
// OpenPGP CFB Mode. http://tools.ietf.org/html/rfc4880#section-13.9
package packet
import (
"crypto/cipher"
)
type ocfbEncrypter struct {
b cipher.Block
fre []byte
outUsed int
}
// An OCFBResyncOption determines if the "resynchronization step" of OCFB is
// performed.
type OCFBResyncOption bool
const (
OCFBResync OCFBResyncOption = true
OCFBNoResync OCFBResyncOption = false
)
// NewOCFBEncrypter returns a cipher.Stream which encrypts data with OpenPGP's
// cipher feedback mode using the given cipher.Block, and an initial amount of
// ciphertext. randData must be random bytes and be the same length as the
// cipher.Block's block size. Resync determines if the "resynchronization step"
// from RFC 4880, 13.9 step 7 is performed. Different parts of OpenPGP vary on
// this point.
func NewOCFBEncrypter(block cipher.Block, randData []byte, resync OCFBResyncOption) (cipher.Stream, []byte) {
blockSize := block.BlockSize()
if len(randData) != blockSize {
return nil, nil
}
x := &ocfbEncrypter{
b: block,
fre: make([]byte, blockSize),
outUsed: 0,
}
prefix := make([]byte, blockSize+2)
block.Encrypt(x.fre, x.fre)
for i := 0; i < blockSize; i++ {
prefix[i] = randData[i] ^ x.fre[i]
}
block.Encrypt(x.fre, prefix[:blockSize])
prefix[blockSize] = x.fre[0] ^ randData[blockSize-2]
prefix[blockSize+1] = x.fre[1] ^ randData[blockSize-1]
if resync {
block.Encrypt(x.fre, prefix[2:])
} else {
x.fre[0] = prefix[blockSize]
x.fre[1] = prefix[blockSize+1]
x.outUsed = 2
}
return x, prefix
}
func (x *ocfbEncrypter) XORKeyStream(dst, src []byte) {
for i := 0; i < len(src); i++ {
if x.outUsed == len(x.fre) {
x.b.Encrypt(x.fre, x.fre)
x.outUsed = 0
}
x.fre[x.outUsed] ^= src[i]
dst[i] = x.fre[x.outUsed]
x.outUsed++
}
}
type ocfbDecrypter struct {
b cipher.Block
fre []byte
outUsed int
}
// NewOCFBDecrypter returns a cipher.Stream which decrypts data with OpenPGP's
// cipher feedback mode using the given cipher.Block. Prefix must be the first
// blockSize + 2 bytes of the ciphertext, where blockSize is the cipher.Block's
// block size. If an incorrect key is detected then nil is returned. On
// successful exit, blockSize+2 bytes of decrypted data are written into
// prefix. Resync determines if the "resynchronization step" from RFC 4880,
// 13.9 step 7 is performed. Different parts of OpenPGP vary on this point.
func NewOCFBDecrypter(block cipher.Block, prefix []byte, resync OCFBResyncOption) cipher.Stream {
blockSize := block.BlockSize()
if len(prefix) != blockSize+2 {
return nil
}
x := &ocfbDecrypter{
b: block,
fre: make([]byte, blockSize),
outUsed: 0,
}
prefixCopy := make([]byte, len(prefix))
copy(prefixCopy, prefix)
block.Encrypt(x.fre, x.fre)
for i := 0; i < blockSize; i++ {
prefixCopy[i] ^= x.fre[i]
}
block.Encrypt(x.fre, prefix[:blockSize])
prefixCopy[blockSize] ^= x.fre[0]
prefixCopy[blockSize+1] ^= x.fre[1]
if prefixCopy[blockSize-2] != prefixCopy[blockSize] ||
prefixCopy[blockSize-1] != prefixCopy[blockSize+1] {
return nil
}
if resync {
block.Encrypt(x.fre, prefix[2:])
} else {
x.fre[0] = prefix[blockSize]
x.fre[1] = prefix[blockSize+1]
x.outUsed = 2
}
copy(prefix, prefixCopy)
return x
}
func (x *ocfbDecrypter) XORKeyStream(dst, src []byte) {
for i := 0; i < len(src); i++ {
if x.outUsed == len(x.fre) {
x.b.Encrypt(x.fre, x.fre)
x.outUsed = 0
}
c := src[i]
dst[i] = x.fre[x.outUsed] ^ src[i]
x.fre[x.outUsed] = c
x.outUsed++
}
}

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// 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"
"encoding/binary"
"io"
"strconv"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/openpgp/s2k"
)
// OnePassSignature represents a one-pass signature packet. See RFC 4880,
// section 5.4.
type OnePassSignature struct {
SigType SignatureType
Hash crypto.Hash
PubKeyAlgo PublicKeyAlgorithm
KeyId uint64
IsLast bool
}
const onePassSignatureVersion = 3
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
}
// 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
}

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// Copyright 2012 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 (
"bytes"
"io"
"io/ioutil"
"github.com/keybase/go-crypto/openpgp/errors"
)
// OpaquePacket represents an OpenPGP packet as raw, unparsed data. This is
// useful for splitting and storing the original packet contents separately,
// handling unsupported packet types or accessing parts of the packet not yet
// implemented by this package.
type OpaquePacket struct {
// Packet type
Tag uint8
// Reason why the packet was parsed opaquely
Reason error
// Binary contents of the packet data
Contents []byte
}
func (op *OpaquePacket) parse(r io.Reader) (err error) {
op.Contents, err = ioutil.ReadAll(r)
return
}
// Serialize marshals the packet to a writer in its original form, including
// the packet header.
func (op *OpaquePacket) Serialize(w io.Writer) (err error) {
err = serializeHeader(w, packetType(op.Tag), len(op.Contents))
if err == nil {
_, err = w.Write(op.Contents)
}
return
}
// Parse attempts to parse the opaque contents into a structure supported by
// this package. If the packet is not known then the result will be another
// OpaquePacket.
func (op *OpaquePacket) Parse() (p Packet, err error) {
hdr := bytes.NewBuffer(nil)
err = serializeHeader(hdr, packetType(op.Tag), len(op.Contents))
if err != nil {
op.Reason = err
return op, err
}
p, err = Read(io.MultiReader(hdr, bytes.NewBuffer(op.Contents)))
if err != nil {
op.Reason = err
p = op
}
return
}
// OpaqueReader reads OpaquePackets from an io.Reader.
type OpaqueReader struct {
r io.Reader
}
func NewOpaqueReader(r io.Reader) *OpaqueReader {
return &OpaqueReader{r: r}
}
// Read the next OpaquePacket.
func (or *OpaqueReader) Next() (op *OpaquePacket, err error) {
tag, _, contents, err := readHeader(or.r)
if err != nil {
return
}
op = &OpaquePacket{Tag: uint8(tag), Reason: err}
err = op.parse(contents)
if err != nil {
consumeAll(contents)
}
return
}
// OpaqueSubpacket represents an unparsed OpenPGP subpacket,
// as found in signature and user attribute packets.
type OpaqueSubpacket struct {
SubType uint8
Contents []byte
}
// OpaqueSubpackets extracts opaque, unparsed OpenPGP subpackets from
// their byte representation.
func OpaqueSubpackets(contents []byte) (result []*OpaqueSubpacket, err error) {
var (
subHeaderLen int
subPacket *OpaqueSubpacket
)
for len(contents) > 0 {
subHeaderLen, subPacket, err = nextSubpacket(contents)
if err != nil {
break
}
result = append(result, subPacket)
contents = contents[subHeaderLen+len(subPacket.Contents):]
}
return
}
func nextSubpacket(contents []byte) (subHeaderLen int, subPacket *OpaqueSubpacket, err error) {
// RFC 4880, section 5.2.3.1
var subLen uint32
if len(contents) < 1 {
goto Truncated
}
subPacket = &OpaqueSubpacket{}
switch {
case contents[0] < 192:
subHeaderLen = 2 // 1 length byte, 1 subtype byte
if len(contents) < subHeaderLen {
goto Truncated
}
subLen = uint32(contents[0])
contents = contents[1:]
case contents[0] < 255:
subHeaderLen = 3 // 2 length bytes, 1 subtype
if len(contents) < subHeaderLen {
goto Truncated
}
subLen = uint32(contents[0]-192)<<8 + uint32(contents[1]) + 192
contents = contents[2:]
default:
subHeaderLen = 6 // 5 length bytes, 1 subtype
if len(contents) < subHeaderLen {
goto Truncated
}
subLen = uint32(contents[1])<<24 |
uint32(contents[2])<<16 |
uint32(contents[3])<<8 |
uint32(contents[4])
contents = contents[5:]
}
if subLen > uint32(len(contents)) || subLen == 0 {
goto Truncated
}
subPacket.SubType = contents[0]
subPacket.Contents = contents[1:subLen]
return
Truncated:
err = errors.StructuralError("subpacket truncated")
return
}
func (osp *OpaqueSubpacket) Serialize(w io.Writer) (err error) {
buf := make([]byte, 6)
n := serializeSubpacketLength(buf, len(osp.Contents)+1)
buf[n] = osp.SubType
if _, err = w.Write(buf[:n+1]); err != nil {
return
}
_, err = w.Write(osp.Contents)
return
}

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@ -0,0 +1,563 @@
// 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 implements parsing and serialization of OpenPGP packets, as
// specified in RFC 4880.
package packet // import "github.com/keybase/go-crypto/openpgp/packet"
import (
"bufio"
"crypto/aes"
"crypto/cipher"
"crypto/des"
"crypto/elliptic"
"io"
"math/big"
"github.com/keybase/go-crypto/cast5"
"github.com/keybase/go-crypto/openpgp/errors"
)
// readFull is the same as io.ReadFull except that reading zero bytes returns
// ErrUnexpectedEOF rather than EOF.
func readFull(r io.Reader, buf []byte) (n int, err error) {
n, err = io.ReadFull(r, buf)
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return
}
// readLength reads an OpenPGP length from r. See RFC 4880, section 4.2.2.
func readLength(r io.Reader) (length int64, isPartial bool, err error) {
var buf [4]byte
_, err = readFull(r, buf[:1])
if err != nil {
return
}
switch {
case buf[0] < 192:
length = int64(buf[0])
case buf[0] < 224:
length = int64(buf[0]-192) << 8
_, err = readFull(r, buf[0:1])
if err != nil {
return
}
length += int64(buf[0]) + 192
case buf[0] < 255:
length = int64(1) << (buf[0] & 0x1f)
isPartial = true
default:
_, err = readFull(r, buf[0:4])
if err != nil {
return
}
length = int64(buf[0])<<24 |
int64(buf[1])<<16 |
int64(buf[2])<<8 |
int64(buf[3])
}
return
}
// partialLengthReader wraps an io.Reader and handles OpenPGP partial lengths.
// The continuation lengths are parsed and removed from the stream and EOF is
// returned at the end of the packet. See RFC 4880, section 4.2.2.4.
type partialLengthReader struct {
r io.Reader
remaining int64
isPartial bool
}
func (r *partialLengthReader) Read(p []byte) (n int, err error) {
for r.remaining == 0 {
if !r.isPartial {
return 0, io.EOF
}
r.remaining, r.isPartial, err = readLength(r.r)
if err != nil {
return 0, err
}
}
toRead := int64(len(p))
if toRead > r.remaining {
toRead = r.remaining
}
n, err = r.r.Read(p[:int(toRead)])
r.remaining -= int64(n)
if n < int(toRead) && err == io.EOF {
err = io.ErrUnexpectedEOF
}
return
}
// partialLengthWriter writes a stream of data using OpenPGP partial lengths.
// See RFC 4880, section 4.2.2.4.
type partialLengthWriter struct {
w io.WriteCloser
lengthByte [1]byte
}
func (w *partialLengthWriter) Write(p []byte) (n int, err error) {
for len(p) > 0 {
for power := uint(14); power < 32; power-- {
l := 1 << power
if len(p) >= l {
w.lengthByte[0] = 224 + uint8(power)
_, err = w.w.Write(w.lengthByte[:])
if err != nil {
return
}
var m int
m, err = w.w.Write(p[:l])
n += m
if err != nil {
return
}
p = p[l:]
break
}
}
}
return
}
func (w *partialLengthWriter) Close() error {
w.lengthByte[0] = 0
_, err := w.w.Write(w.lengthByte[:])
if err != nil {
return err
}
return w.w.Close()
}
// A spanReader is an io.LimitReader, but it returns ErrUnexpectedEOF if the
// underlying Reader returns EOF before the limit has been reached.
type spanReader struct {
r io.Reader
n int64
}
func (l *spanReader) Read(p []byte) (n int, err error) {
if l.n <= 0 {
return 0, io.EOF
}
if int64(len(p)) > l.n {
p = p[0:l.n]
}
n, err = l.r.Read(p)
l.n -= int64(n)
if l.n > 0 && err == io.EOF {
err = io.ErrUnexpectedEOF
}
return
}
// readHeader parses a packet header and returns an io.Reader which will return
// the contents of the packet. See RFC 4880, section 4.2.
func readHeader(r io.Reader) (tag packetType, length int64, contents io.Reader, err error) {
var buf [4]byte
_, err = io.ReadFull(r, buf[:1])
if err != nil {
return
}
if buf[0]&0x80 == 0 {
err = errors.StructuralError("tag byte does not have MSB set")
return
}
if buf[0]&0x40 == 0 {
// Old format packet
tag = packetType((buf[0] & 0x3f) >> 2)
lengthType := buf[0] & 3
if lengthType == 3 {
length = -1
contents = r
return
}
lengthBytes := 1 << lengthType
_, err = readFull(r, buf[0:lengthBytes])
if err != nil {
return
}
for i := 0; i < lengthBytes; i++ {
length <<= 8
length |= int64(buf[i])
}
contents = &spanReader{r, length}
return
}
// New format packet
tag = packetType(buf[0] & 0x3f)
length, isPartial, err := readLength(r)
if err != nil {
return
}
if isPartial {
contents = &partialLengthReader{
remaining: length,
isPartial: true,
r: r,
}
length = -1
} else {
contents = &spanReader{r, length}
}
return
}
// serializeHeader writes an OpenPGP packet header to w. See RFC 4880, section
// 4.2.
func serializeHeader(w io.Writer, ptype packetType, length int) (err error) {
var buf [6]byte
var n int
buf[0] = 0x80 | 0x40 | byte(ptype)
if length < 192 {
buf[1] = byte(length)
n = 2
} else if length < 8384 {
length -= 192
buf[1] = 192 + byte(length>>8)
buf[2] = byte(length)
n = 3
} else {
buf[1] = 255
buf[2] = byte(length >> 24)
buf[3] = byte(length >> 16)
buf[4] = byte(length >> 8)
buf[5] = byte(length)
n = 6
}
_, err = w.Write(buf[:n])
return
}
// serializeStreamHeader writes an OpenPGP packet header to w where the
// length of the packet is unknown. It returns a io.WriteCloser which can be
// used to write the contents of the packet. See RFC 4880, section 4.2.
func serializeStreamHeader(w io.WriteCloser, ptype packetType) (out io.WriteCloser, err error) {
var buf [1]byte
buf[0] = 0x80 | 0x40 | byte(ptype)
_, err = w.Write(buf[:])
if err != nil {
return
}
out = &partialLengthWriter{w: w}
return
}
// Packet represents an OpenPGP packet. Users are expected to try casting
// instances of this interface to specific packet types.
type Packet interface {
parse(io.Reader) error
}
// consumeAll reads from the given Reader until error, returning the number of
// bytes read.
func consumeAll(r io.Reader) (n int64, err error) {
var m int
var buf [1024]byte
for {
m, err = r.Read(buf[:])
n += int64(m)
if err == io.EOF {
err = nil
return
}
if err != nil {
return
}
}
panic("unreachable")
}
// packetType represents the numeric ids of the different OpenPGP packet types. See
// http://www.iana.org/assignments/pgp-parameters/pgp-parameters.xhtml#pgp-parameters-2
type packetType uint8
const (
packetTypeEncryptedKey packetType = 1
packetTypeSignature packetType = 2
packetTypeSymmetricKeyEncrypted packetType = 3
packetTypeOnePassSignature packetType = 4
packetTypePrivateKey packetType = 5
packetTypePublicKey packetType = 6
packetTypePrivateSubkey packetType = 7
packetTypeCompressed packetType = 8
packetTypeSymmetricallyEncrypted packetType = 9
packetTypeLiteralData packetType = 11
packetTypeUserId packetType = 13
packetTypePublicSubkey packetType = 14
packetTypeUserAttribute packetType = 17
packetTypeSymmetricallyEncryptedMDC packetType = 18
)
// peekVersion detects the version of a public key packet about to
// be read. A bufio.Reader at the original position of the io.Reader
// is returned.
func peekVersion(r io.Reader) (bufr *bufio.Reader, ver byte, err error) {
bufr = bufio.NewReader(r)
var verBuf []byte
if verBuf, err = bufr.Peek(1); err != nil {
return
}
ver = verBuf[0]
return
}
// Read reads a single OpenPGP packet from the given io.Reader. If there is an
// error parsing a packet, the whole packet is consumed from the input.
func Read(r io.Reader) (p Packet, err error) {
tag, _, contents, err := readHeader(r)
if err != nil {
return
}
switch tag {
case packetTypeEncryptedKey:
p = new(EncryptedKey)
case packetTypeSignature:
var version byte
// Detect signature version
if contents, version, err = peekVersion(contents); err != nil {
return
}
if version < 4 {
p = new(SignatureV3)
} else {
p = new(Signature)
}
case packetTypeSymmetricKeyEncrypted:
p = new(SymmetricKeyEncrypted)
case packetTypeOnePassSignature:
p = new(OnePassSignature)
case packetTypePrivateKey, packetTypePrivateSubkey:
pk := new(PrivateKey)
if tag == packetTypePrivateSubkey {
pk.IsSubkey = true
}
p = pk
case packetTypePublicKey, packetTypePublicSubkey:
var version byte
if contents, version, err = peekVersion(contents); err != nil {
return
}
isSubkey := tag == packetTypePublicSubkey
if version < 4 {
p = &PublicKeyV3{IsSubkey: isSubkey}
} else {
p = &PublicKey{IsSubkey: isSubkey}
}
case packetTypeCompressed:
p = new(Compressed)
case packetTypeSymmetricallyEncrypted:
p = new(SymmetricallyEncrypted)
case packetTypeLiteralData:
p = new(LiteralData)
case packetTypeUserId:
p = new(UserId)
case packetTypeUserAttribute:
p = new(UserAttribute)
case packetTypeSymmetricallyEncryptedMDC:
se := new(SymmetricallyEncrypted)
se.MDC = true
p = se
default:
err = errors.UnknownPacketTypeError(tag)
}
if p != nil {
err = p.parse(contents)
}
if err != nil {
consumeAll(contents)
}
return
}
// SignatureType represents the different semantic meanings of an OpenPGP
// signature. See RFC 4880, section 5.2.1.
type SignatureType uint8
const (
SigTypeBinary SignatureType = 0
SigTypeText = 1
SigTypeGenericCert = 0x10
SigTypePersonaCert = 0x11
SigTypeCasualCert = 0x12
SigTypePositiveCert = 0x13
SigTypeSubkeyBinding = 0x18
SigTypePrimaryKeyBinding = 0x19
SigTypeDirectSignature = 0x1F
SigTypeKeyRevocation = 0x20
SigTypeSubkeyRevocation = 0x28
SigTypeIdentityRevocation = 0x30
)
// PublicKeyAlgorithm represents the different public key system specified for
// OpenPGP. See
// http://www.iana.org/assignments/pgp-parameters/pgp-parameters.xhtml#pgp-parameters-12
type PublicKeyAlgorithm uint8
const (
PubKeyAlgoRSA PublicKeyAlgorithm = 1
PubKeyAlgoRSAEncryptOnly PublicKeyAlgorithm = 2
PubKeyAlgoRSASignOnly PublicKeyAlgorithm = 3
PubKeyAlgoElGamal PublicKeyAlgorithm = 16
PubKeyAlgoDSA PublicKeyAlgorithm = 17
// RFC 6637, Section 5.
PubKeyAlgoECDH PublicKeyAlgorithm = 18
PubKeyAlgoECDSA PublicKeyAlgorithm = 19
// RFC -1
PubKeyAlgoEdDSA PublicKeyAlgorithm = 22
)
// CanEncrypt returns true if it's possible to encrypt a message to a public
// key of the given type.
func (pka PublicKeyAlgorithm) CanEncrypt() bool {
switch pka {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoElGamal, PubKeyAlgoECDH:
return true
}
return false
}
// CanSign returns true if it's possible for a public key of the given type to
// sign a message.
func (pka PublicKeyAlgorithm) CanSign() bool {
switch pka {
case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly, PubKeyAlgoDSA, PubKeyAlgoECDSA, PubKeyAlgoEdDSA:
return true
}
return false
}
// CipherFunction represents the different block ciphers specified for OpenPGP. See
// http://www.iana.org/assignments/pgp-parameters/pgp-parameters.xhtml#pgp-parameters-13
type CipherFunction uint8
const (
Cipher3DES CipherFunction = 2
CipherCAST5 CipherFunction = 3
CipherAES128 CipherFunction = 7
CipherAES192 CipherFunction = 8
CipherAES256 CipherFunction = 9
)
// KeySize returns the key size, in bytes, of cipher.
func (cipher CipherFunction) KeySize() int {
switch cipher {
case Cipher3DES:
return 24
case CipherCAST5:
return cast5.KeySize
case CipherAES128:
return 16
case CipherAES192:
return 24
case CipherAES256:
return 32
}
return 0
}
// blockSize returns the block size, in bytes, of cipher.
func (cipher CipherFunction) blockSize() int {
switch cipher {
case Cipher3DES:
return des.BlockSize
case CipherCAST5:
return 8
case CipherAES128, CipherAES192, CipherAES256:
return 16
}
return 0
}
// new returns a fresh instance of the given cipher.
func (cipher CipherFunction) new(key []byte) (block cipher.Block) {
switch cipher {
case Cipher3DES:
block, _ = des.NewTripleDESCipher(key)
case CipherCAST5:
block, _ = cast5.NewCipher(key)
case CipherAES128, CipherAES192, CipherAES256:
block, _ = aes.NewCipher(key)
}
return
}
// readMPI reads a big integer from r. The bit length returned is the bit
// length that was specified in r. This is preserved so that the integer can be
// reserialized exactly.
func readMPI(r io.Reader) (mpi []byte, bitLength uint16, err error) {
var buf [2]byte
_, err = readFull(r, buf[0:])
if err != nil {
return
}
bitLength = uint16(buf[0])<<8 | uint16(buf[1])
numBytes := (int(bitLength) + 7) / 8
mpi = make([]byte, numBytes)
_, err = readFull(r, mpi)
return
}
// mpiLength returns the length of the given *big.Int when serialized as an
// MPI.
func mpiLength(n *big.Int) (mpiLengthInBytes int) {
mpiLengthInBytes = 2 /* MPI length */
mpiLengthInBytes += (n.BitLen() + 7) / 8
return
}
// writeMPI serializes a big integer to w.
func writeMPI(w io.Writer, bitLength uint16, mpiBytes []byte) (err error) {
_, err = w.Write([]byte{byte(bitLength >> 8), byte(bitLength)})
if err == nil {
_, err = w.Write(mpiBytes)
}
return
}
func WritePaddedBigInt(w io.Writer, length int, X *big.Int) (n int, err error) {
bytes := X.Bytes()
n1, err := w.Write(make([]byte, length-len(bytes)))
if err != nil {
return n1, err
}
n2, err := w.Write(bytes)
if err != nil {
return n2, err
}
return (n1 + n2), err
}
// Minimum number of bytes to fit the curve coordinates. All
// coordinates have to be 0-padded to this length.
func mpiPointByteLength(curve elliptic.Curve) int {
return (curve.Params().P.BitLen() + 7) / 8
}
// writeBig serializes a *big.Int to w.
func writeBig(w io.Writer, i *big.Int) error {
return writeMPI(w, uint16(i.BitLen()), i.Bytes())
}
// CompressionAlgo Represents the different compression algorithms
// supported by OpenPGP (except for BZIP2, which is not currently
// supported). See Section 9.3 of RFC 4880.
type CompressionAlgo uint8
const (
CompressionNone CompressionAlgo = 0
CompressionZIP CompressionAlgo = 1
CompressionZLIB CompressionAlgo = 2
)

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// 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 (
"bytes"
"crypto/cipher"
"crypto/dsa"
"crypto/ecdsa"
"crypto/sha1"
"fmt"
"io"
"io/ioutil"
"math/big"
"strconv"
"time"
"github.com/keybase/go-crypto/ed25519"
"github.com/keybase/go-crypto/openpgp/ecdh"
"github.com/keybase/go-crypto/openpgp/elgamal"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/openpgp/s2k"
"github.com/keybase/go-crypto/rsa"
)
// PrivateKey represents a possibly encrypted private key. See RFC 4880,
// section 5.5.3.
type PrivateKey struct {
PublicKey
Encrypted bool // if true then the private key is unavailable until Decrypt has been called.
encryptedData []byte
cipher CipherFunction
s2k func(out, in []byte)
PrivateKey interface{} // An *rsa.PrivateKey or *dsa.PrivateKey.
sha1Checksum bool
iv []byte
s2kHeader []byte
}
type EdDSAPrivateKey struct {
PrivateKey
seed parsedMPI
}
func (e *EdDSAPrivateKey) Sign(digest []byte) (R, S []byte, err error) {
r := bytes.NewReader(e.seed.bytes)
publicKey, privateKey, err := ed25519.GenerateKey(r)
if err != nil {
return nil, nil, err
}
if !bytes.Equal(publicKey, e.PublicKey.edk.p.bytes[1:]) { // [1:] because [0] is 0x40 mpi header
return nil, nil, errors.UnsupportedError("EdDSA: Private key does not match public key.")
}
sig := ed25519.Sign(privateKey, digest)
sigLen := ed25519.SignatureSize / 2
return sig[:sigLen], sig[sigLen:], nil
}
func NewRSAPrivateKey(currentTime time.Time, priv *rsa.PrivateKey) *PrivateKey {
pk := new(PrivateKey)
pk.PublicKey = *NewRSAPublicKey(currentTime, &priv.PublicKey)
pk.PrivateKey = priv
return pk
}
func NewDSAPrivateKey(currentTime time.Time, priv *dsa.PrivateKey) *PrivateKey {
pk := new(PrivateKey)
pk.PublicKey = *NewDSAPublicKey(currentTime, &priv.PublicKey)
pk.PrivateKey = priv
return pk
}
func NewElGamalPrivateKey(currentTime time.Time, priv *elgamal.PrivateKey) *PrivateKey {
pk := new(PrivateKey)
pk.PublicKey = *NewElGamalPublicKey(currentTime, &priv.PublicKey)
pk.PrivateKey = priv
return pk
}
func NewECDSAPrivateKey(currentTime time.Time, priv *ecdsa.PrivateKey) *PrivateKey {
pk := new(PrivateKey)
pk.PublicKey = *NewECDSAPublicKey(currentTime, &priv.PublicKey)
pk.PrivateKey = priv
return pk
}
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
}
// S2K == nil implies that we got a "GNU Dummy" S2K. For instance,
// because our master secret key is on a USB key in a vault somewhere.
// In that case, there is no further data to consume here.
if pk.s2k == nil {
pk.Encrypted = false
return
}
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
}
func mod64kHash(d []byte) uint16 {
var h uint16
for _, b := range d {
h += uint16(b)
}
return h
}
// Encrypt is the counterpart to the Decrypt() method below. It encrypts
// the private key with the provided passphrase. If config is nil, then
// the standard, and sensible, defaults apply.
//
// A key will be derived from the given passphrase using S2K Specifier
// Type 3 (Iterated + Salted, see RFC-4880 Sec. 3.7.1.3). This choice
// is hardcoded in s2k.Serialize(). S2KCount is hardcoded to 0, which is
// equivalent to 65536. And the hash algorithm for key-derivation can be
// set with config. The encrypted PrivateKey, using the algorithm specified
// in config (if provided), is written out to the encryptedData member.
// When Serialize() is called, this encryptedData member will be
// serialized, using S2K Usage value of 254, and thus SHA1 checksum.
func (pk *PrivateKey) Encrypt(passphrase []byte, config *Config) (err error) {
if pk.PrivateKey == nil {
return errors.InvalidArgumentError("there is no private key to encrypt")
}
pk.sha1Checksum = true
pk.cipher = config.Cipher()
s2kConfig := s2k.Config{
Hash: config.Hash(),
S2KCount: 0,
}
s2kBuf := bytes.NewBuffer(nil)
derivedKey := make([]byte, pk.cipher.KeySize())
err = s2k.Serialize(s2kBuf, derivedKey, config.Random(), passphrase, &s2kConfig)
if err != nil {
return err
}
pk.s2kHeader = s2kBuf.Bytes()
// No good way to set pk.s2k but to call s2k.Parse(),
// even though we have all the information here, but
// most of the functions needed are private to s2k.
pk.s2k, err = s2k.Parse(s2kBuf)
pk.iv = make([]byte, pk.cipher.blockSize())
if _, err = config.Random().Read(pk.iv); err != nil {
return err
}
privateKeyBuf := bytes.NewBuffer(nil)
if err = pk.serializePrivateKey(privateKeyBuf); err != nil {
return err
}
checksum := sha1.Sum(privateKeyBuf.Bytes())
if _, err = privateKeyBuf.Write(checksum[:]); err != nil {
return err
}
pkData := privateKeyBuf.Bytes()
block := pk.cipher.new(derivedKey)
pk.encryptedData = make([]byte, len(pkData))
cfb := cipher.NewCFBEncrypter(block, pk.iv)
cfb.XORKeyStream(pk.encryptedData, pkData)
pk.Encrypted = true
return nil
}
func (pk *PrivateKey) Serialize(w io.Writer) (err error) {
buf := bytes.NewBuffer(nil)
err = pk.PublicKey.serializeWithoutHeaders(buf)
if err != nil {
return
}
privateKeyBuf := bytes.NewBuffer(nil)
if pk.PrivateKey == nil {
_, err = buf.Write([]byte{
254, // SHA-1 Convention
9, // Encryption scheme (AES256)
101, // GNU Extensions
2, // Hash value (SHA1)
'G', 'N', 'U', // "GNU" as a string
1, // Extension type 1001 (minus 1000)
})
} else if pk.Encrypted {
_, err = buf.Write([]byte{
254, // SHA-1 Convention
byte(pk.cipher), // Encryption scheme
})
if err != nil {
return err
}
if _, err = buf.Write(pk.s2kHeader); err != nil {
return err
}
if _, err = buf.Write(pk.iv); err != nil {
return err
}
if _, err = privateKeyBuf.Write(pk.encryptedData); err != nil {
return err
}
} else {
buf.WriteByte(0 /* no encryption */)
if err = pk.serializePrivateKey(privateKeyBuf); err != nil {
return err
}
}
ptype := packetTypePrivateKey
contents := buf.Bytes()
privateKeyBytes := privateKeyBuf.Bytes()
if pk.IsSubkey {
ptype = packetTypePrivateSubkey
}
totalLen := len(contents) + len(privateKeyBytes)
if !pk.Encrypted {
totalLen += 2
}
err = serializeHeader(w, ptype, totalLen)
if err != nil {
return
}
_, err = w.Write(contents)
if err != nil {
return
}
_, err = w.Write(privateKeyBytes)
if err != nil {
return
}
if len(privateKeyBytes) > 0 && !pk.Encrypted {
checksum := mod64kHash(privateKeyBytes)
var checksumBytes [2]byte
checksumBytes[0] = byte(checksum >> 8)
checksumBytes[1] = byte(checksum)
_, err = w.Write(checksumBytes[:])
}
return
}
func (pk *PrivateKey) serializePrivateKey(w io.Writer) (err error) {
switch priv := pk.PrivateKey.(type) {
case *rsa.PrivateKey:
err = serializeRSAPrivateKey(w, priv)
case *dsa.PrivateKey:
err = serializeDSAPrivateKey(w, priv)
case *elgamal.PrivateKey:
err = serializeElGamalPrivateKey(w, priv)
case *ecdsa.PrivateKey:
err = serializeECDSAPrivateKey(w, priv)
case *ecdh.PrivateKey:
err = serializeECDHPrivateKey(w, priv)
case *EdDSAPrivateKey:
err = serializeEdDSAPrivateKey(w, priv)
default:
err = errors.InvalidArgumentError("unknown private key type")
}
return err
}
func serializeRSAPrivateKey(w io.Writer, priv *rsa.PrivateKey) error {
err := writeBig(w, priv.D)
if err != nil {
return err
}
err = writeBig(w, priv.Primes[1])
if err != nil {
return err
}
err = writeBig(w, priv.Primes[0])
if err != nil {
return err
}
return writeBig(w, priv.Precomputed.Qinv)
}
func serializeDSAPrivateKey(w io.Writer, priv *dsa.PrivateKey) error {
return writeBig(w, priv.X)
}
func serializeElGamalPrivateKey(w io.Writer, priv *elgamal.PrivateKey) error {
return writeBig(w, priv.X)
}
func serializeECDSAPrivateKey(w io.Writer, priv *ecdsa.PrivateKey) error {
return writeBig(w, priv.D)
}
func serializeECDHPrivateKey(w io.Writer, priv *ecdh.PrivateKey) error {
return writeBig(w, priv.X)
}
func serializeEdDSAPrivateKey(w io.Writer, priv *EdDSAPrivateKey) error {
return writeMPI(w, priv.seed.bitLength, priv.seed.bytes)
}
// Decrypt decrypts an encrypted private key using a passphrase.
func (pk *PrivateKey) Decrypt(passphrase []byte) error {
if !pk.Encrypted {
return nil
}
// For GNU Dummy S2K, there's no key here, so don't do anything.
if pk.s2k == nil {
return nil
}
key := make([]byte, pk.cipher.KeySize())
pk.s2k(key, passphrase)
block := pk.cipher.new(key)
cfb := cipher.NewCFBDecrypter(block, pk.iv)
data := make([]byte, len(pk.encryptedData))
cfb.XORKeyStream(data, pk.encryptedData)
if pk.sha1Checksum {
if len(data) < sha1.Size {
return errors.StructuralError("truncated private key data")
}
h := sha1.New()
h.Write(data[:len(data)-sha1.Size])
sum := h.Sum(nil)
if !bytes.Equal(sum, data[len(data)-sha1.Size:]) {
return errors.StructuralError("private key checksum failure")
}
data = data[:len(data)-sha1.Size]
} else {
if len(data) < 2 {
return errors.StructuralError("truncated private key data")
}
var sum uint16
for i := 0; i < len(data)-2; i++ {
sum += uint16(data[i])
}
if data[len(data)-2] != uint8(sum>>8) ||
data[len(data)-1] != uint8(sum) {
return errors.StructuralError("private key checksum failure")
}
data = data[:len(data)-2]
}
return pk.parsePrivateKey(data)
}
func (pk *PrivateKey) parsePrivateKey(data []byte) (err error) {
switch pk.PublicKey.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly, PubKeyAlgoRSAEncryptOnly:
return pk.parseRSAPrivateKey(data)
case PubKeyAlgoDSA:
return pk.parseDSAPrivateKey(data)
case PubKeyAlgoElGamal:
return pk.parseElGamalPrivateKey(data)
case PubKeyAlgoECDSA:
return pk.parseECDSAPrivateKey(data)
case PubKeyAlgoECDH:
return pk.parseECDHPrivateKey(data)
case PubKeyAlgoEdDSA:
return pk.parseEdDSAPrivateKey(data)
}
panic("impossible")
}
func (pk *PrivateKey) parseRSAPrivateKey(data []byte) (err error) {
rsaPub := pk.PublicKey.PublicKey.(*rsa.PublicKey)
rsaPriv := new(rsa.PrivateKey)
rsaPriv.PublicKey = *rsaPub
buf := bytes.NewBuffer(data)
d, _, err := readMPI(buf)
if err != nil {
return
}
p, _, err := readMPI(buf)
if err != nil {
return
}
q, _, err := readMPI(buf)
if err != nil {
return
}
rsaPriv.D = new(big.Int).SetBytes(d)
rsaPriv.Primes = make([]*big.Int, 2)
rsaPriv.Primes[0] = new(big.Int).SetBytes(p)
rsaPriv.Primes[1] = new(big.Int).SetBytes(q)
if err := rsaPriv.Validate(); err != nil {
return err
}
rsaPriv.Precompute()
pk.PrivateKey = rsaPriv
pk.Encrypted = false
pk.encryptedData = nil
return nil
}
func (pk *PrivateKey) parseDSAPrivateKey(data []byte) (err error) {
dsaPub := pk.PublicKey.PublicKey.(*dsa.PublicKey)
dsaPriv := new(dsa.PrivateKey)
dsaPriv.PublicKey = *dsaPub
buf := bytes.NewBuffer(data)
x, _, err := readMPI(buf)
if err != nil {
return
}
dsaPriv.X = new(big.Int).SetBytes(x)
pk.PrivateKey = dsaPriv
pk.Encrypted = false
pk.encryptedData = nil
return nil
}
func (pk *PrivateKey) parseElGamalPrivateKey(data []byte) (err error) {
pub := pk.PublicKey.PublicKey.(*elgamal.PublicKey)
priv := new(elgamal.PrivateKey)
priv.PublicKey = *pub
buf := bytes.NewBuffer(data)
x, _, err := readMPI(buf)
if err != nil {
return
}
priv.X = new(big.Int).SetBytes(x)
pk.PrivateKey = priv
pk.Encrypted = false
pk.encryptedData = nil
return nil
}
func (pk *PrivateKey) parseECDHPrivateKey(data []byte) (err error) {
pub := pk.PublicKey.PublicKey.(*ecdh.PublicKey)
priv := new(ecdh.PrivateKey)
priv.PublicKey = *pub
buf := bytes.NewBuffer(data)
d, _, err := readMPI(buf)
if err != nil {
return
}
priv.X = new(big.Int).SetBytes(d)
pk.PrivateKey = priv
pk.Encrypted = false
pk.encryptedData = nil
return nil
}
func (pk *PrivateKey) parseECDSAPrivateKey(data []byte) (err error) {
ecdsaPub := pk.PublicKey.PublicKey.(*ecdsa.PublicKey)
ecdsaPriv := new(ecdsa.PrivateKey)
ecdsaPriv.PublicKey = *ecdsaPub
buf := bytes.NewBuffer(data)
d, _, err := readMPI(buf)
if err != nil {
return
}
ecdsaPriv.D = new(big.Int).SetBytes(d)
pk.PrivateKey = ecdsaPriv
pk.Encrypted = false
pk.encryptedData = nil
return nil
}
func (pk *PrivateKey) parseEdDSAPrivateKey(data []byte) (err error) {
eddsaPriv := new(EdDSAPrivateKey)
eddsaPriv.PublicKey = pk.PublicKey
buf := bytes.NewBuffer(data)
eddsaPriv.seed.bytes, eddsaPriv.seed.bitLength, err = readMPI(buf)
if err != nil {
return err
}
if bLen := len(eddsaPriv.seed.bytes); bLen != 32 { // 32 bytes private part of ed25519 key.
return errors.UnsupportedError(fmt.Sprintf("Unexpected EdDSA private key length: %d", bLen))
}
pk.PrivateKey = eddsaPriv
pk.Encrypted = false
pk.encryptedData = nil
return nil
}

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@ -0,0 +1,930 @@
// 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 (
"bytes"
"crypto"
"crypto/dsa"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/sha1"
_ "crypto/sha256"
_ "crypto/sha512"
"encoding/binary"
"fmt"
"hash"
"io"
"math/big"
"strconv"
"time"
"github.com/keybase/go-crypto/brainpool"
"github.com/keybase/go-crypto/curve25519"
"github.com/keybase/go-crypto/ed25519"
"github.com/keybase/go-crypto/openpgp/ecdh"
"github.com/keybase/go-crypto/openpgp/elgamal"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/rsa"
)
var (
// NIST curve P-256
oidCurveP256 []byte = []byte{0x2A, 0x86, 0x48, 0xCE, 0x3D, 0x03, 0x01, 0x07}
// NIST curve P-384
oidCurveP384 []byte = []byte{0x2B, 0x81, 0x04, 0x00, 0x22}
// NIST curve P-521
oidCurveP521 []byte = []byte{0x2B, 0x81, 0x04, 0x00, 0x23}
// Brainpool curve P-256r1
oidCurveP256r1 []byte = []byte{0x2B, 0x24, 0x03, 0x03, 0x02, 0x08, 0x01, 0x01, 0x07}
// Brainpool curve P-384r1
oidCurveP384r1 []byte = []byte{0x2B, 0x24, 0x03, 0x03, 0x02, 0x08, 0x01, 0x01, 0x0B}
// Brainpool curve P-512r1
oidCurveP512r1 []byte = []byte{0x2B, 0x24, 0x03, 0x03, 0x02, 0x08, 0x01, 0x01, 0x0D}
// EdDSA
oidEdDSA []byte = []byte{0x2B, 0x06, 0x01, 0x04, 0x01, 0xDA, 0x47, 0x0F, 0x01}
// cv25519
oidCurve25519 []byte = []byte{0x2B, 0x06, 0x01, 0x04, 0x01, 0x97, 0x55, 0x01, 0x05, 0x01}
)
const maxOIDLength = 10
// ecdsaKey stores the algorithm-specific fields for ECDSA keys.
// as defined in RFC 6637, Section 9.
type ecdsaKey struct {
// oid contains the OID byte sequence identifying the elliptic curve used
oid []byte
// p contains the elliptic curve point that represents the public key
p parsedMPI
}
type edDSAkey struct {
ecdsaKey
}
func copyFrontFill(dst, src []byte, length int) int {
if srcLen := len(src); srcLen < length {
return copy(dst[length-srcLen:], src[:])
} else {
return copy(dst[:], src[:])
}
}
func (e *edDSAkey) Verify(payload []byte, r parsedMPI, s parsedMPI) bool {
const halfSigSize = ed25519.SignatureSize / 2
var sig [ed25519.SignatureSize]byte
// NOTE: The first byte is 0x40 - MPI header
// TODO: Maybe clean the code up and use 0x40 as a header when
// reading and keep only actual number in p field. Find out how
// other MPIs are stored.
key := e.p.bytes[1:]
// Note: it may happen that R + S do not form 64-byte signature buffer that
// ed25519 expects, but because we copy it over to an array of exact size,
// we will always pass correctly sized slice to Verify. Slice too short
// would make ed25519 panic().
copyFrontFill(sig[:halfSigSize], r.bytes, halfSigSize)
copyFrontFill(sig[halfSigSize:], s.bytes, halfSigSize)
return ed25519.Verify(key, payload, sig[:])
}
// 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
}
func (f *ecdsaKey) parse(r io.Reader) (err error) {
if f.oid, err = parseOID(r); err != nil {
return err
}
f.p.bytes, f.p.bitLength, err = readMPI(r)
return err
}
func (f *ecdsaKey) serialize(w io.Writer) (err error) {
buf := make([]byte, maxOIDLength+1)
buf[0] = byte(len(f.oid))
copy(buf[1:], f.oid)
if _, err = w.Write(buf[:len(f.oid)+1]); err != nil {
return
}
return writeMPIs(w, f.p)
}
func getCurveByOid(oid []byte) elliptic.Curve {
switch {
case bytes.Equal(oid, oidCurveP256):
return elliptic.P256()
case bytes.Equal(oid, oidCurveP384):
return elliptic.P384()
case bytes.Equal(oid, oidCurveP521):
return elliptic.P521()
case bytes.Equal(oid, oidCurveP256r1):
return brainpool.P256r1()
case bytes.Equal(oid, oidCurveP384r1):
return brainpool.P384r1()
case bytes.Equal(oid, oidCurveP512r1):
return brainpool.P512r1()
case bytes.Equal(oid, oidCurve25519):
return curve25519.Cv25519()
default:
return nil
}
}
func (f *ecdsaKey) newECDSA() (*ecdsa.PublicKey, error) {
var c = getCurveByOid(f.oid)
// Curve25519 should not be used in ECDSA.
if c == nil || bytes.Equal(f.oid, oidCurve25519) {
return nil, errors.UnsupportedError(fmt.Sprintf("unsupported oid: %x", f.oid))
}
// Note: Unmarshal already checks if point is on curve.
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
}
func (f *ecdsaKey) newECDH() (*ecdh.PublicKey, error) {
var c = getCurveByOid(f.oid)
if c == nil {
return nil, errors.UnsupportedError(fmt.Sprintf("unsupported oid: %x", f.oid))
}
// ecdh.Unmarshal handles unmarshaling for all curve types. It
// also checks if point is on curve.
x, y := ecdh.Unmarshal(c, f.p.bytes)
if x == nil {
return nil, errors.UnsupportedError("failed to parse EC point")
}
return &ecdh.PublicKey{Curve: c, X: x, Y: y}, nil
}
func (f *ecdsaKey) byteLen() int {
return 1 + len(f.oid) + 2 + len(f.p.bytes)
}
type kdfHashFunction byte
type kdfAlgorithm byte
// ecdhKdf stores key derivation function parameters
// used for ECDH encryption. See RFC 6637, Section 9.
type ecdhKdf struct {
KdfHash kdfHashFunction
KdfAlgo kdfAlgorithm
}
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
}
func (f *ecdhKdf) serialize(w io.Writer) (err error) {
buf := make([]byte, 4)
// See RFC 6637, Section 9, Algorithm-Specific Fields for ECDH keys.
buf[0] = byte(0x03) // Length of the following fields
buf[1] = byte(0x01) // Reserved for future extensions, must be 1 for now
buf[2] = byte(f.KdfHash)
buf[3] = byte(f.KdfAlgo)
_, err = w.Write(buf[:])
return
}
func (f *ecdhKdf) byteLen() int {
return 4
}
// PublicKey represents an OpenPGP public key. See RFC 4880, section 5.5.2.
type PublicKey struct {
CreationTime time.Time
PubKeyAlgo PublicKeyAlgorithm
PublicKey interface{} // *rsa.PublicKey, *dsa.PublicKey or *ecdsa.PublicKey
Fingerprint [20]byte
KeyId uint64
IsSubkey bool
n, e, p, q, g, y parsedMPI
// RFC 6637 fields
ec *ecdsaKey
ecdh *ecdhKdf
// EdDSA fields (no RFC available), uses ecdsa scaffolding
edk *edDSAkey
}
// signingKey provides a convenient abstraction over signature verification
// for v3 and v4 public keys.
type signingKey interface {
SerializeSignaturePrefix(io.Writer)
serializeWithoutHeaders(io.Writer) error
}
func FromBig(n *big.Int) parsedMPI {
return parsedMPI{
bytes: n.Bytes(),
bitLength: uint16(n.BitLen()),
}
}
func FromBytes(bytes []byte) parsedMPI {
return parsedMPI{
bytes: bytes,
bitLength: uint16(8 * len(bytes)),
}
}
// NewRSAPublicKey returns a PublicKey that wraps the given rsa.PublicKey.
func NewRSAPublicKey(creationTime time.Time, pub *rsa.PublicKey) *PublicKey {
pk := &PublicKey{
CreationTime: creationTime,
PubKeyAlgo: PubKeyAlgoRSA,
PublicKey: pub,
n: FromBig(pub.N),
e: FromBig(big.NewInt(int64(pub.E))),
}
pk.setFingerPrintAndKeyId()
return pk
}
// NewDSAPublicKey returns a PublicKey that wraps the given dsa.PublicKey.
func NewDSAPublicKey(creationTime time.Time, pub *dsa.PublicKey) *PublicKey {
pk := &PublicKey{
CreationTime: creationTime,
PubKeyAlgo: PubKeyAlgoDSA,
PublicKey: pub,
p: FromBig(pub.P),
q: FromBig(pub.Q),
g: FromBig(pub.G),
y: FromBig(pub.Y),
}
pk.setFingerPrintAndKeyId()
return pk
}
// check EdDSA public key material.
// There is currently no RFC for it, but it doesn't mean it's not
// implemented or in use.
func (e *edDSAkey) check() error {
if !bytes.Equal(e.oid, oidEdDSA) {
return errors.UnsupportedError(fmt.Sprintf("Bad OID for EdDSA key: %v", e.oid))
}
if bLen := len(e.p.bytes); bLen != 33 { // 32 bytes for ed25519 key and 1 byte for 0x40 header
return errors.UnsupportedError(fmt.Sprintf("Unexpected EdDSA public key length: %d", bLen))
}
return nil
}
// NewElGamalPublicKey returns a PublicKey that wraps the given elgamal.PublicKey.
func NewElGamalPublicKey(creationTime time.Time, pub *elgamal.PublicKey) *PublicKey {
pk := &PublicKey{
CreationTime: creationTime,
PubKeyAlgo: PubKeyAlgoElGamal,
PublicKey: pub,
p: FromBig(pub.P),
g: FromBig(pub.G),
y: FromBig(pub.Y),
}
pk.setFingerPrintAndKeyId()
return pk
}
func NewECDSAPublicKey(creationTime time.Time, pub *ecdsa.PublicKey) *PublicKey {
pk := &PublicKey{
CreationTime: creationTime,
PubKeyAlgo: PubKeyAlgoECDSA,
PublicKey: pub,
ec: new(ecdsaKey),
}
switch pub.Curve {
case elliptic.P256():
pk.ec.oid = oidCurveP256
case elliptic.P384():
pk.ec.oid = oidCurveP384
case elliptic.P521():
pk.ec.oid = oidCurveP521
case brainpool.P256r1():
pk.ec.oid = oidCurveP256r1
case brainpool.P384r1():
pk.ec.oid = oidCurveP384r1
case brainpool.P512r1():
pk.ec.oid = oidCurveP512r1
}
pk.ec.p.bytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)
pk.ec.p.bitLength = uint16(8 * len(pk.ec.p.bytes))
pk.setFingerPrintAndKeyId()
return pk
}
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 PubKeyAlgoEdDSA:
pk.edk = new(edDSAkey)
if err = pk.edk.parse(r); err != nil {
return err
}
err = pk.edk.check()
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
}
pk.PublicKey, err = pk.ec.newECDH()
default:
err = errors.UnsupportedError("public key type: " + strconv.Itoa(int(pk.PubKeyAlgo)))
}
if err != nil {
return
}
pk.setFingerPrintAndKeyId()
return
}
func (pk *PublicKey) setFingerPrintAndKeyId() {
// RFC 4880, section 12.2
fingerPrint := sha1.New()
pk.SerializeSignaturePrefix(fingerPrint)
pk.serializeWithoutHeaders(fingerPrint)
copy(pk.Fingerprint[:], fingerPrint.Sum(nil))
pk.KeyId = binary.BigEndian.Uint64(pk.Fingerprint[12:20])
}
// 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) > 7 {
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 |= int64(pk.e.bytes[i])
}
pk.PublicKey = rsa
return
}
// parseDSA parses DSA public key material from the given Reader. See RFC 4880,
// section 5.5.2.
func (pk *PublicKey) parseDSA(r io.Reader) (err error) {
pk.p.bytes, pk.p.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.q.bytes, pk.q.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.g.bytes, pk.g.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.y.bytes, pk.y.bitLength, err = readMPI(r)
if err != nil {
return
}
dsa := new(dsa.PublicKey)
dsa.P = new(big.Int).SetBytes(pk.p.bytes)
dsa.Q = new(big.Int).SetBytes(pk.q.bytes)
dsa.G = new(big.Int).SetBytes(pk.g.bytes)
dsa.Y = new(big.Int).SetBytes(pk.y.bytes)
pk.PublicKey = dsa
return
}
// parseElGamal parses ElGamal public key material from the given Reader. See
// RFC 4880, section 5.5.2.
func (pk *PublicKey) parseElGamal(r io.Reader) (err error) {
pk.p.bytes, pk.p.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.g.bytes, pk.g.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.y.bytes, pk.y.bitLength, err = readMPI(r)
if err != nil {
return
}
elgamal := new(elgamal.PublicKey)
elgamal.P = new(big.Int).SetBytes(pk.p.bytes)
elgamal.G = new(big.Int).SetBytes(pk.g.bytes)
elgamal.Y = new(big.Int).SetBytes(pk.y.bytes)
pk.PublicKey = elgamal
return
}
// SerializeSignaturePrefix writes the prefix for this public key to the given Writer.
// The prefix is used when calculating a signature over this public key. See
// RFC 4880, section 5.2.4.
func (pk *PublicKey) SerializeSignaturePrefix(h io.Writer) {
var pLength uint16
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
pLength += 2 + uint16(len(pk.n.bytes))
pLength += 2 + uint16(len(pk.e.bytes))
case PubKeyAlgoDSA:
pLength += 2 + uint16(len(pk.p.bytes))
pLength += 2 + uint16(len(pk.q.bytes))
pLength += 2 + uint16(len(pk.g.bytes))
pLength += 2 + uint16(len(pk.y.bytes))
case PubKeyAlgoElGamal:
pLength += 2 + uint16(len(pk.p.bytes))
pLength += 2 + uint16(len(pk.g.bytes))
pLength += 2 + uint16(len(pk.y.bytes))
case PubKeyAlgoECDSA:
pLength += uint16(pk.ec.byteLen())
case PubKeyAlgoECDH:
pLength += uint16(pk.ec.byteLen())
pLength += uint16(pk.ecdh.byteLen())
case PubKeyAlgoEdDSA:
pLength += uint16(pk.edk.byteLen())
default:
panic("unknown public key algorithm")
}
pLength += 6
h.Write([]byte{0x99, byte(pLength >> 8), byte(pLength)})
return
}
func (pk *PublicKey) Serialize(w io.Writer) (err error) {
length := 6 // 6 byte header
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
length += 2 + len(pk.n.bytes)
length += 2 + len(pk.e.bytes)
case PubKeyAlgoDSA:
length += 2 + len(pk.p.bytes)
length += 2 + len(pk.q.bytes)
length += 2 + len(pk.g.bytes)
length += 2 + len(pk.y.bytes)
case PubKeyAlgoElGamal:
length += 2 + len(pk.p.bytes)
length += 2 + len(pk.g.bytes)
length += 2 + len(pk.y.bytes)
case PubKeyAlgoECDSA:
length += pk.ec.byteLen()
case PubKeyAlgoECDH:
length += pk.ec.byteLen()
length += pk.ecdh.byteLen()
case PubKeyAlgoEdDSA:
length += pk.edk.byteLen()
default:
panic("unknown public key algorithm")
}
packetType := packetTypePublicKey
if pk.IsSubkey {
packetType = packetTypePublicSubkey
}
err = serializeHeader(w, packetType, length)
if err != nil {
return
}
return pk.serializeWithoutHeaders(w)
}
// serializeWithoutHeaders marshals the PublicKey to w in the form of an
// OpenPGP public key packet, not including the packet header.
func (pk *PublicKey) serializeWithoutHeaders(w io.Writer) (err error) {
var buf [6]byte
buf[0] = 4
t := uint32(pk.CreationTime.Unix())
buf[1] = byte(t >> 24)
buf[2] = byte(t >> 16)
buf[3] = byte(t >> 8)
buf[4] = byte(t)
buf[5] = byte(pk.PubKeyAlgo)
_, err = w.Write(buf[:])
if err != nil {
return
}
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
return writeMPIs(w, pk.n, pk.e)
case PubKeyAlgoDSA:
return writeMPIs(w, pk.p, pk.q, pk.g, pk.y)
case PubKeyAlgoElGamal:
return writeMPIs(w, pk.p, pk.g, pk.y)
case PubKeyAlgoECDSA:
return pk.ec.serialize(w)
case PubKeyAlgoEdDSA:
return pk.edk.serialize(w)
case PubKeyAlgoECDH:
if err = pk.ec.serialize(w); err != nil {
return
}
return pk.ecdh.serialize(w)
}
return errors.InvalidArgumentError("bad public-key algorithm")
}
// CanSign returns true iff this public key can generate signatures
func (pk *PublicKey) CanSign() bool {
return pk.PubKeyAlgo != PubKeyAlgoRSAEncryptOnly && pk.PubKeyAlgo != PubKeyAlgoElGamal
}
// VerifySignature returns nil iff sig is a valid signature, made by this
// public key, of the data hashed into signed. signed is mutated by this call.
func (pk *PublicKey) VerifySignature(signed hash.Hash, sig *Signature) (err error) {
if !pk.CanSign() {
return errors.InvalidArgumentError("public key cannot generate signatures")
}
signed.Write(sig.HashSuffix)
hashBytes := signed.Sum(nil)
// NOTE(maxtaco) 2016-08-22
//
// We used to do this:
//
// if hashBytes[0] != sig.HashTag[0] || hashBytes[1] != sig.HashTag[1] {
// return errors.SignatureError("hash tag doesn't match")
// }
//
// But don't do anything in this case. Some GPGs generate bad
// 2-byte hash prefixes, but GPG also doesn't seem to care on
// import. See BrentMaxwell's key. I think it's safe to disable
// this check!
if pk.PubKeyAlgo != sig.PubKeyAlgo {
return errors.InvalidArgumentError("public key and signature use different algorithms")
}
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
rsaPublicKey, _ := pk.PublicKey.(*rsa.PublicKey)
err = rsa.VerifyPKCS1v15(rsaPublicKey, sig.Hash, hashBytes, sig.RSASignature.bytes)
if err != nil {
return errors.SignatureError("RSA verification failure")
}
return nil
case PubKeyAlgoDSA:
dsaPublicKey, _ := pk.PublicKey.(*dsa.PublicKey)
// Need to truncate hashBytes to match FIPS 186-3 section 4.6.
subgroupSize := (dsaPublicKey.Q.BitLen() + 7) / 8
if len(hashBytes) > subgroupSize {
hashBytes = hashBytes[:subgroupSize]
}
if !dsa.Verify(dsaPublicKey, hashBytes, new(big.Int).SetBytes(sig.DSASigR.bytes), new(big.Int).SetBytes(sig.DSASigS.bytes)) {
return errors.SignatureError("DSA verification failure")
}
return nil
case PubKeyAlgoECDSA:
ecdsaPublicKey := pk.PublicKey.(*ecdsa.PublicKey)
if !ecdsa.Verify(ecdsaPublicKey, hashBytes, new(big.Int).SetBytes(sig.ECDSASigR.bytes), new(big.Int).SetBytes(sig.ECDSASigS.bytes)) {
return errors.SignatureError("ECDSA verification failure")
}
return nil
case PubKeyAlgoEdDSA:
if !pk.edk.Verify(hashBytes, sig.EdDSASigR, sig.EdDSASigS) {
return errors.SignatureError("EdDSA verification failure")
}
return nil
default:
return errors.SignatureError("Unsupported public key algorithm used in signature")
}
panic("unreachable")
}
// VerifySignatureV3 returns nil iff sig is a valid signature, made by this
// public key, of the data hashed into signed. signed is mutated by this call.
func (pk *PublicKey) VerifySignatureV3(signed hash.Hash, sig *SignatureV3) (err error) {
if !pk.CanSign() {
return errors.InvalidArgumentError("public key cannot generate signatures")
}
suffix := make([]byte, 5)
suffix[0] = byte(sig.SigType)
binary.BigEndian.PutUint32(suffix[1:], uint32(sig.CreationTime.Unix()))
signed.Write(suffix)
hashBytes := signed.Sum(nil)
if hashBytes[0] != sig.HashTag[0] || hashBytes[1] != sig.HashTag[1] {
return errors.SignatureError("hash tag doesn't match")
}
if pk.PubKeyAlgo != sig.PubKeyAlgo {
return errors.InvalidArgumentError("public key and signature use different algorithms")
}
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
rsaPublicKey := pk.PublicKey.(*rsa.PublicKey)
if err = rsa.VerifyPKCS1v15(rsaPublicKey, sig.Hash, hashBytes, sig.RSASignature.bytes); err != nil {
return errors.SignatureError("RSA verification failure")
}
return
case PubKeyAlgoDSA:
dsaPublicKey := pk.PublicKey.(*dsa.PublicKey)
// Need to truncate hashBytes to match FIPS 186-3 section 4.6.
subgroupSize := (dsaPublicKey.Q.BitLen() + 7) / 8
if len(hashBytes) > subgroupSize {
hashBytes = hashBytes[:subgroupSize]
}
if !dsa.Verify(dsaPublicKey, hashBytes, new(big.Int).SetBytes(sig.DSASigR.bytes), new(big.Int).SetBytes(sig.DSASigS.bytes)) {
return errors.SignatureError("DSA verification failure")
}
return nil
default:
panic("shouldn't happen")
}
panic("unreachable")
}
// keySignatureHash returns a Hash of the message that needs to be signed for
// pk to assert a subkey relationship to signed.
func keySignatureHash(pk, signed signingKey, hashFunc crypto.Hash) (h hash.Hash, err error) {
if !hashFunc.Available() {
return nil, errors.UnsupportedError("hash function")
}
h = hashFunc.New()
updateKeySignatureHash(pk, signed, h)
return
}
// updateKeySignatureHash does the actual hash updates for keySignatureHash.
func updateKeySignatureHash(pk, signed signingKey, h hash.Hash) {
// RFC 4880, section 5.2.4
pk.SerializeSignaturePrefix(h)
pk.serializeWithoutHeaders(h)
signed.SerializeSignaturePrefix(h)
signed.serializeWithoutHeaders(h)
}
// VerifyKeySignature returns nil iff sig is a valid signature, made by this
// public key, of signed.
func (pk *PublicKey) VerifyKeySignature(signed *PublicKey, sig *Signature) error {
h, err := keySignatureHash(pk, signed, sig.Hash)
if err != nil {
return err
}
if err = pk.VerifySignature(h, sig); err != nil {
return err
}
if sig.FlagSign {
// BUG(maxtaco)
//
// We should check for more than FlagsSign here, because if
// you read keys.go, we can sometimes use signing subkeys even if they're
// not explicitly flagged as such. However, so doing fails lots of currently
// working tests, so I'm not going to do much here.
//
// In other words, we should have this disjunction in the condition above:
//
// || (!sig.FlagsValid && pk.PubKeyAlgo.CanSign()) {
//
// Signing subkeys must be cross-signed. See
// https://www.gnupg.org/faq/subkey-cross-certify.html.
if sig.EmbeddedSignature == nil {
return errors.StructuralError("signing subkey is missing cross-signature")
}
// Verify the cross-signature. This is calculated over the same
// data as the main signature, so we cannot just recursively
// call signed.VerifyKeySignature(...)
if h, err = keySignatureHash(pk, signed, sig.EmbeddedSignature.Hash); err != nil {
return errors.StructuralError("error while hashing for cross-signature: " + err.Error())
}
if err := signed.VerifySignature(h, sig.EmbeddedSignature); err != nil {
return errors.StructuralError("error while verifying cross-signature: " + err.Error())
}
}
return nil
}
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
}
// VerifyRevocationSignature returns nil iff sig is a valid signature, made by this
// public key.
func (pk *PublicKey) VerifyRevocationSignature(revokedKey *PublicKey, sig *Signature) (err error) {
h, err := keyRevocationHash(revokedKey, sig.Hash)
if err != nil {
return err
}
return pk.VerifySignature(h, sig)
}
type teeHash struct {
h hash.Hash
}
func (t teeHash) Write(b []byte) (n int, err error) {
fmt.Printf("hash -> %s %+v\n", string(b), b)
return t.h.Write(b)
}
func (t teeHash) Sum(b []byte) []byte { return t.h.Sum(b) }
func (t teeHash) Reset() { t.h.Reset() }
func (t teeHash) Size() int { return t.h.Size() }
func (t teeHash) BlockSize() int { return t.h.BlockSize() }
// 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()
updateUserIdSignatureHash(id, pk, h)
return
}
// updateUserIdSignatureHash does the actual hash updates for
// userIdSignatureHash.
func updateUserIdSignatureHash(id string, pk *PublicKey, h hash.Hash) {
// 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
}
// VerifyUserIdSignature returns nil iff sig is a valid signature, made by this
// public key, that id is the identity of pub.
func (pk *PublicKey) VerifyUserIdSignature(id string, pub *PublicKey, sig *Signature) (err error) {
h, err := userIdSignatureHash(id, pub, sig.Hash)
if err != nil {
return err
}
return pk.VerifySignature(h, sig)
}
// VerifyUserIdSignatureV3 returns nil iff sig is a valid signature, made by this
// public key, that id is the identity of pub.
func (pk *PublicKey) VerifyUserIdSignatureV3(id string, pub *PublicKey, sig *SignatureV3) (err error) {
h, err := userIdSignatureV3Hash(id, pub, sig.Hash)
if err != nil {
return err
}
return pk.VerifySignatureV3(h, sig)
}
// KeyIdString returns the public key's fingerprint in capital hex
// (e.g. "6C7EE1B8621CC013").
func (pk *PublicKey) KeyIdString() string {
return fmt.Sprintf("%X", pk.Fingerprint[12:20])
}
// KeyIdShortString returns the short form of public key's fingerprint
// in capital hex, as shown by gpg --list-keys (e.g. "621CC013").
func (pk *PublicKey) KeyIdShortString() string {
return fmt.Sprintf("%X", pk.Fingerprint[16:20])
}
// A parsedMPI is used to store the contents of a big integer, along with the
// bit length that was specified in the original input. This allows the MPI to
// be reserialized exactly.
type parsedMPI struct {
bytes []byte
bitLength uint16
}
// writeMPIs is a utility function for serializing several big integers to the
// given Writer.
func writeMPIs(w io.Writer, mpis ...parsedMPI) (err error) {
for _, mpi := range mpis {
err = writeMPI(w, mpi.bitLength, mpi.bytes)
if err != nil {
return
}
}
return
}
// BitLength returns the bit length for the given public key. Used for
// displaying key information, actual buffers and BigInts inside may
// have non-matching different size if the key is invalid.
func (pk *PublicKey) BitLength() (bitLength uint16, err error) {
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
bitLength = pk.n.bitLength
case PubKeyAlgoDSA:
bitLength = pk.p.bitLength
case PubKeyAlgoElGamal:
bitLength = pk.p.bitLength
case PubKeyAlgoECDH:
ecdhPublicKey := pk.PublicKey.(*ecdh.PublicKey)
bitLength = uint16(ecdhPublicKey.Curve.Params().BitSize)
case PubKeyAlgoECDSA:
ecdsaPublicKey := pk.PublicKey.(*ecdsa.PublicKey)
bitLength = uint16(ecdsaPublicKey.Curve.Params().BitSize)
case PubKeyAlgoEdDSA:
// EdDSA only support ed25519 curves right now, just return
// the length. Also, we don't have any PublicKey.Curve object
// to look the size up from.
bitLength = 256
default:
err = errors.InvalidArgumentError("bad public-key algorithm")
}
return
}

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@ -0,0 +1,280 @@
// Copyright 2013 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/md5"
"encoding/binary"
"fmt"
"hash"
"io"
"math/big"
"strconv"
"time"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/rsa"
)
// PublicKeyV3 represents older, version 3 public keys. These keys are less secure and
// should not be used for signing or encrypting. They are supported here only for
// parsing version 3 key material and validating signatures.
// See RFC 4880, section 5.5.2.
type PublicKeyV3 struct {
CreationTime time.Time
DaysToExpire uint16
PubKeyAlgo PublicKeyAlgorithm
PublicKey *rsa.PublicKey
Fingerprint [16]byte
KeyId uint64
IsSubkey bool
n, e parsedMPI
}
// newRSAPublicKeyV3 returns a PublicKey that wraps the given rsa.PublicKey.
// Included here for testing purposes only. RFC 4880, section 5.5.2:
// "an implementation MUST NOT generate a V3 key, but MAY accept it."
func newRSAPublicKeyV3(creationTime time.Time, pub *rsa.PublicKey) *PublicKeyV3 {
pk := &PublicKeyV3{
CreationTime: creationTime,
PublicKey: pub,
n: FromBig(pub.N),
e: FromBig(big.NewInt(int64(pub.E))),
}
pk.setFingerPrintAndKeyId()
return pk
}
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
}
func (pk *PublicKeyV3) setFingerPrintAndKeyId() {
// RFC 4880, section 12.2
fingerPrint := md5.New()
fingerPrint.Write(pk.n.bytes)
fingerPrint.Write(pk.e.bytes)
fingerPrint.Sum(pk.Fingerprint[:0])
pk.KeyId = binary.BigEndian.Uint64(pk.n.bytes[len(pk.n.bytes)-8:])
}
// 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) > 7 {
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 |= int64(pk.e.bytes[i])
}
pk.PublicKey = rsa
return
}
// SerializeSignaturePrefix writes the prefix for this public key to the given Writer.
// The prefix is used when calculating a signature over this public key. See
// RFC 4880, section 5.2.4.
func (pk *PublicKeyV3) SerializeSignaturePrefix(w io.Writer) {
var pLength uint16
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
pLength += 2 + uint16(len(pk.n.bytes))
pLength += 2 + uint16(len(pk.e.bytes))
default:
panic("unknown public key algorithm")
}
pLength += 6
w.Write([]byte{0x99, byte(pLength >> 8), byte(pLength)})
return
}
func (pk *PublicKeyV3) Serialize(w io.Writer) (err error) {
length := 8 // 8 byte header
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
length += 2 + len(pk.n.bytes)
length += 2 + len(pk.e.bytes)
default:
panic("unknown public key algorithm")
}
packetType := packetTypePublicKey
if pk.IsSubkey {
packetType = packetTypePublicSubkey
}
if err = serializeHeader(w, packetType, length); err != nil {
return
}
return pk.serializeWithoutHeaders(w)
}
// serializeWithoutHeaders marshals the PublicKey to w in the form of an
// OpenPGP public key packet, not including the packet header.
func (pk *PublicKeyV3) serializeWithoutHeaders(w io.Writer) (err error) {
var buf [8]byte
// Version 3
buf[0] = 3
// Creation time
t := uint32(pk.CreationTime.Unix())
buf[1] = byte(t >> 24)
buf[2] = byte(t >> 16)
buf[3] = byte(t >> 8)
buf[4] = byte(t)
// Days to expire
buf[5] = byte(pk.DaysToExpire >> 8)
buf[6] = byte(pk.DaysToExpire)
// Public key algorithm
buf[7] = byte(pk.PubKeyAlgo)
if _, err = w.Write(buf[:]); err != nil {
return
}
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
return writeMPIs(w, pk.n, pk.e)
}
return errors.InvalidArgumentError("bad public-key algorithm")
}
// CanSign returns true iff this public key can generate signatures
func (pk *PublicKeyV3) CanSign() bool {
return pk.PubKeyAlgo != PubKeyAlgoRSAEncryptOnly
}
// VerifySignatureV3 returns nil iff sig is a valid signature, made by this
// public key, of the data hashed into signed. signed is mutated by this call.
func (pk *PublicKeyV3) VerifySignatureV3(signed hash.Hash, sig *SignatureV3) (err error) {
if !pk.CanSign() {
return errors.InvalidArgumentError("public key cannot generate signatures")
}
suffix := make([]byte, 5)
suffix[0] = byte(sig.SigType)
binary.BigEndian.PutUint32(suffix[1:], uint32(sig.CreationTime.Unix()))
signed.Write(suffix)
hashBytes := signed.Sum(nil)
if hashBytes[0] != sig.HashTag[0] || hashBytes[1] != sig.HashTag[1] {
return errors.SignatureError("hash tag doesn't match")
}
if pk.PubKeyAlgo != sig.PubKeyAlgo {
return errors.InvalidArgumentError("public key and signature use different algorithms")
}
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
if err = rsa.VerifyPKCS1v15(pk.PublicKey, sig.Hash, hashBytes, sig.RSASignature.bytes); err != nil {
return errors.SignatureError("RSA verification failure")
}
return
default:
// V3 public keys only support RSA.
panic("shouldn't happen")
}
panic("unreachable")
}
// VerifyUserIdSignatureV3 returns nil iff sig is a valid signature, made by this
// public key, that id is the identity of pub.
func (pk *PublicKeyV3) VerifyUserIdSignatureV3(id string, pub *PublicKeyV3, sig *SignatureV3) (err error) {
h, err := userIdSignatureV3Hash(id, pk, sig.Hash)
if err != nil {
return err
}
return pk.VerifySignatureV3(h, sig)
}
// VerifyKeySignatureV3 returns nil iff sig is a valid signature, made by this
// public key, of signed.
func (pk *PublicKeyV3) VerifyKeySignatureV3(signed *PublicKeyV3, sig *SignatureV3) (err error) {
h, err := keySignatureHash(pk, signed, sig.Hash)
if err != nil {
return err
}
return pk.VerifySignatureV3(h, sig)
}
// 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
}
// KeyIdString returns the public key's fingerprint in capital hex
// (e.g. "6C7EE1B8621CC013").
func (pk *PublicKeyV3) KeyIdString() string {
return fmt.Sprintf("%X", pk.KeyId)
}
// KeyIdShortString returns the short form of public key's fingerprint
// in capital hex, as shown by gpg --list-keys (e.g. "621CC013").
func (pk *PublicKeyV3) KeyIdShortString() string {
return fmt.Sprintf("%X", pk.KeyId&0xFFFFFFFF)
}
// BitLength returns the bit length for the given public key.
func (pk *PublicKeyV3) BitLength() (bitLength uint16, err error) {
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
bitLength = pk.n.bitLength
default:
err = errors.InvalidArgumentError("bad public-key algorithm")
}
return
}

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@ -0,0 +1,76 @@
// 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 (
"io"
"github.com/keybase/go-crypto/openpgp/errors"
)
// Reader reads packets from an io.Reader and allows packets to be 'unread' so
// that they result from the next call to Next.
type Reader struct {
q []Packet
readers []io.Reader
}
// New io.Readers are pushed when a compressed or encrypted packet is processed
// and recursively treated as a new source of packets. However, a carefully
// crafted packet can trigger an infinite recursive sequence of packets. See
// http://mumble.net/~campbell/misc/pgp-quine
// https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2013-4402
// This constant limits the number of recursive packets that may be pushed.
const maxReaders = 32
// Next returns the most recently unread Packet, or reads another packet from
// the top-most io.Reader. Unknown packet types are skipped.
func (r *Reader) Next() (p Packet, err error) {
if len(r.q) > 0 {
p = r.q[len(r.q)-1]
r.q = r.q[:len(r.q)-1]
return
}
for len(r.readers) > 0 {
p, err = Read(r.readers[len(r.readers)-1])
if err == nil {
return
}
if err == io.EOF {
r.readers = r.readers[:len(r.readers)-1]
continue
}
if _, ok := err.(errors.UnknownPacketTypeError); !ok {
return nil, err
}
}
return nil, io.EOF
}
// Push causes the Reader to start reading from a new io.Reader. When an EOF
// error is seen from the new io.Reader, it is popped and the Reader continues
// to read from the next most recent io.Reader. Push returns a StructuralError
// if pushing the reader would exceed the maximum recursion level, otherwise it
// returns nil.
func (r *Reader) Push(reader io.Reader) (err error) {
if len(r.readers) >= maxReaders {
return errors.StructuralError("too many layers of packets")
}
r.readers = append(r.readers, reader)
return nil
}
// Unread causes the given Packet to be returned from the next call to Next.
func (r *Reader) Unread(p Packet) {
r.q = append(r.q, p)
}
func NewReader(r io.Reader) *Reader {
return &Reader{
q: nil,
readers: []io.Reader{r},
}
}

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@ -0,0 +1,880 @@
// 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 (
"bytes"
"crypto"
"crypto/dsa"
"crypto/ecdsa"
"encoding/binary"
"hash"
"io"
"strconv"
"time"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/openpgp/s2k"
"github.com/keybase/go-crypto/rsa"
)
const (
// See RFC 4880, section 5.2.3.21 for details.
KeyFlagCertify = 1 << iota
KeyFlagSign
KeyFlagEncryptCommunications
KeyFlagEncryptStorage
)
// Signer can be implemented by application code to do actual signing.
type Signer interface {
hash.Hash
Sign(sig *Signature) error
KeyId() uint64
PublicKeyAlgo() PublicKeyAlgorithm
}
// RevocationKey represents designated revoker packet. See RFC 4880
// section 5.2.3.15 for details.
type RevocationKey struct {
Class byte
PublicKeyAlgo PublicKeyAlgorithm
Fingerprint []byte
}
// KeyFlagBits holds boolean whether any usage flags were provided in
// the signature and BitField with KeyFlag* flags.
type KeyFlagBits struct {
Valid bool
BitField byte
}
// 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 time.Time
RSASignature parsedMPI
DSASigR, DSASigS parsedMPI
ECDSASigR, ECDSASigS parsedMPI
EdDSASigR, EdDSASigS 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
PreferredKeyServer string
IssuerKeyId *uint64
IsPrimaryId *bool
IssuerFingerprint []byte
// 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
// RevocationReason is set if this signature has been revoked.
// See RFC 4880, section 5.2.3.23 for details.
RevocationReason *uint8
RevocationReasonText string
// PolicyURI is optional. See RFC 4880, Section 5.2.3.20 for details
PolicyURI string
// Regex is a regex that can match a PGP UID. See RFC 4880, 5.2.3.14 for details
Regex string
// MDC is set if this signature has a feature packet that indicates
// support for MDC subpackets.
MDC bool
// EmbeddedSignature, if non-nil, is a signature of the parent key, by
// this key. This prevents an attacker from claiming another's signing
// subkey as their own.
EmbeddedSignature *Signature
// StubbedOutCriticalError is not fail-stop, since it shouldn't break key parsing
// when appearing in WoT-style cross signatures. But it should prevent a signature
// from being applied to a primary or subkey.
StubbedOutCriticalError error
// DesignaterRevoker will be present if this signature certifies a
// designated revoking key id (3rd party key that can sign
// revocation for this key).
DesignatedRevoker *RevocationKey
outSubpackets []outputSubpacket
}
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, PubKeyAlgoEdDSA:
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 PubKeyAlgoEdDSA:
sig.EdDSASigR.bytes, sig.EdDSASigR.bitLength, err = readMPI(r)
if err == nil {
sig.EdDSASigS.bytes, sig.EdDSASigS.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
}
// 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 error) {
for len(subpackets) > 0 {
subpackets, err = parseSignatureSubpacket(sig, subpackets, isHashed)
if err != nil {
return
}
}
if sig.CreationTime.IsZero() {
err = errors.StructuralError("no creation time in signature")
}
return
}
type signatureSubpacketType uint8
const (
creationTimeSubpacket signatureSubpacketType = 2
signatureExpirationSubpacket signatureSubpacketType = 3
regularExpressionSubpacket signatureSubpacketType = 6
keyExpirationSubpacket signatureSubpacketType = 9
prefSymmetricAlgosSubpacket signatureSubpacketType = 11
revocationKey signatureSubpacketType = 12
issuerSubpacket signatureSubpacketType = 16
prefHashAlgosSubpacket signatureSubpacketType = 21
prefCompressionSubpacket signatureSubpacketType = 22
prefKeyServerSubpacket signatureSubpacketType = 24
primaryUserIdSubpacket signatureSubpacketType = 25
policyURISubpacket signatureSubpacketType = 26
keyFlagsSubpacket signatureSubpacketType = 27
reasonForRevocationSubpacket signatureSubpacketType = 29
featuresSubpacket signatureSubpacketType = 30
embeddedSignatureSubpacket signatureSubpacketType = 32
issuerFingerprint signatureSubpacketType = 33
)
// parseSignatureSubpacket parses a single subpacket. len(subpacket) is >= 1.
func parseSignatureSubpacket(sig *Signature, subpacket []byte, isHashed bool) (rest []byte, err 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 = errors.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 = errors.StructuralError("signature creation time in non-hashed area")
return
}
if len(subpacket) != 4 {
err = errors.StructuralError("signature creation time not four bytes")
return
}
t := binary.BigEndian.Uint32(subpacket)
sig.CreationTime = time.Unix(int64(t), 0)
case signatureExpirationSubpacket:
// Signature expiration time, section 5.2.3.10
if !isHashed {
return
}
if len(subpacket) != 4 {
err = errors.StructuralError("expiration subpacket with bad length")
return
}
sig.SigLifetimeSecs = new(uint32)
*sig.SigLifetimeSecs = binary.BigEndian.Uint32(subpacket)
case keyExpirationSubpacket:
// Key expiration time, section 5.2.3.6
if !isHashed {
return
}
if len(subpacket) != 4 {
err = errors.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 = errors.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 = errors.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 = errors.StructuralError("empty key flags subpacket")
return
}
sig.FlagsValid = true
if subpacket[0]&KeyFlagCertify != 0 {
sig.FlagCertify = true
}
if subpacket[0]&KeyFlagSign != 0 {
sig.FlagSign = true
}
if subpacket[0]&KeyFlagEncryptCommunications != 0 {
sig.FlagEncryptCommunications = true
}
if subpacket[0]&KeyFlagEncryptStorage != 0 {
sig.FlagEncryptStorage = true
}
case reasonForRevocationSubpacket:
// Reason For Revocation, section 5.2.3.23
if !isHashed {
return
}
if len(subpacket) == 0 {
err = errors.StructuralError("empty revocation reason subpacket")
return
}
sig.RevocationReason = new(uint8)
*sig.RevocationReason = subpacket[0]
sig.RevocationReasonText = string(subpacket[1:])
case featuresSubpacket:
// Features subpacket, section 5.2.3.24 specifies a very general
// mechanism for OpenPGP implementations to signal support for new
// features. In practice, the subpacket is used exclusively to
// indicate support for MDC-protected encryption.
sig.MDC = len(subpacket) >= 1 && subpacket[0]&1 == 1
case embeddedSignatureSubpacket:
// Only usage is in signatures that cross-certify
// signing subkeys. section 5.2.3.26 describes the
// format, with its usage described in section 11.1
if sig.EmbeddedSignature != nil {
err = errors.StructuralError("Cannot have multiple embedded signatures")
return
}
sig.EmbeddedSignature = new(Signature)
// Embedded signatures are required to be v4 signatures see
// section 12.1. However, we only parse v4 signatures in this
// file anyway.
if err := sig.EmbeddedSignature.parse(bytes.NewBuffer(subpacket)); err != nil {
return nil, err
}
if sigType := sig.EmbeddedSignature.SigType; sigType != SigTypePrimaryKeyBinding {
return nil, errors.StructuralError("cross-signature has unexpected type " + strconv.Itoa(int(sigType)))
}
case policyURISubpacket:
// See RFC 4880, Section 5.2.3.20
sig.PolicyURI = string(subpacket[:])
case regularExpressionSubpacket:
sig.Regex = string(subpacket[:])
if isCritical {
sig.StubbedOutCriticalError = errors.UnsupportedError("regex support is stubbed out")
}
case prefKeyServerSubpacket:
sig.PreferredKeyServer = string(subpacket[:])
case issuerFingerprint:
// The first byte is how many bytes the fingerprint is, but we'll just
// read until the end of the subpacket, so we'll ignore it.
sig.IssuerFingerprint = append([]byte{}, subpacket[1:]...)
case revocationKey:
// Authorizes the specified key to issue revocation signatures
// for a key.
// TODO: Class octet must have bit 0x80 set. If the bit 0x40
// is set, then this means that the revocation information is
// sensitive.
sig.DesignatedRevoker = &RevocationKey{
Class: subpacket[0],
PublicKeyAlgo: PublicKeyAlgorithm(subpacket[1]),
Fingerprint: append([]byte{}, subpacket[2:]...),
}
default:
if isCritical {
err = errors.UnsupportedError("unknown critical signature subpacket type " + strconv.Itoa(int(packetType)))
return
}
}
return
Truncated:
err = errors.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 {
// RFC 4880, Section 4.2.2.
if length < 192 {
to[0] = byte(length)
return 1
}
if length < 16320 {
length -= 192
to[0] = byte((length >> 8) + 192)
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
}
// KeyExpired returns whether sig is a self-signature of a key that has
// expired.
func (sig *Signature) KeyExpired(currentTime time.Time) bool {
if sig.KeyLifetimeSecs == nil {
return false
}
expiry := sig.CreationTime.Add(time.Duration(*sig.KeyLifetimeSecs) * time.Second)
return currentTime.After(expiry)
}
// ExpiresBeforeOther checks if other signature has expiration at
// later date than sig.
func (sig *Signature) ExpiresBeforeOther(other *Signature) bool {
if sig.KeyLifetimeSecs == nil {
// This sig never expires, or has infinitely long expiration
// time.
return false
} else if other.KeyLifetimeSecs == nil {
// This sig expires at some non-infinite point, but the other
// sig never expires.
return true
}
getExpiryDate := func(s *Signature) time.Time {
return s.CreationTime.Add(time.Duration(*s.KeyLifetimeSecs) * time.Second)
}
return getExpiryDate(other).After(getExpiryDate(sig))
}
// buildHashSuffix constructs the HashSuffix member of sig in preparation for signing.
func (sig *Signature) buildHashSuffix() (err 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 errors.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 error) {
err = sig.buildHashSuffix()
if err != nil {
return
}
h.Write(sig.HashSuffix)
digest = h.Sum(nil)
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.
// If config is nil, sensible defaults will be used.
func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey, config *Config) (err error) {
signer, hashIsSigner := h.(Signer)
if !hashIsSigner && (priv == nil || priv.PrivateKey == nil) {
err = errors.InvalidArgumentError("attempting to sign with nil PrivateKey")
return
}
sig.outSubpackets = sig.buildSubpackets()
digest, err := sig.signPrepareHash(h)
if err != nil {
return
}
if hashIsSigner {
err = signer.Sign(sig)
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))
}
case PubKeyAlgoECDSA:
r, s, err := ecdsa.Sign(config.Random(), priv.PrivateKey.(*ecdsa.PrivateKey), digest)
if err == nil {
sig.ECDSASigR = FromBig(r)
sig.ECDSASigS = FromBig(s)
}
case PubKeyAlgoEdDSA:
r, s, err := priv.PrivateKey.(*EdDSAPrivateKey).Sign(digest)
if err == nil {
sig.EdDSASigR = FromBytes(r)
sig.EdDSASigS = FromBytes(s)
}
default:
err = errors.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.
// If config is nil, sensible defaults will be used.
func (sig *Signature) SignUserId(id string, pub *PublicKey, priv *PrivateKey, config *Config) error {
h, err := userIdSignatureHash(id, pub, sig.Hash)
if err != nil {
return err
}
return sig.Sign(h, priv, config)
}
// SignUserIdWithSigner 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.
// If config is nil, sensible defaults will be used.
func (sig *Signature) SignUserIdWithSigner(id string, pub *PublicKey, s Signer, config *Config) error {
updateUserIdSignatureHash(id, pub, s)
return sig.Sign(s, nil, config)
}
// 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.
// If config is nil, sensible defaults will be used.
func (sig *Signature) SignKey(pub *PublicKey, priv *PrivateKey, config *Config) error {
h, err := keySignatureHash(&priv.PublicKey, pub, sig.Hash)
if err != nil {
return err
}
return sig.Sign(h, priv, config)
}
// SignKeyWithSigner computes a signature using s, asserting that
// signeePubKey is a subkey. 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) SignKeyWithSigner(signeePubKey *PublicKey, signerPubKey *PublicKey, s Signer, config *Config) error {
updateKeySignatureHash(signerPubKey, signeePubKey, s)
return sig.Sign(s, nil, config)
}
// Serialize marshals sig to w. Sign, SignUserId or SignKey must have been
// called first.
func (sig *Signature) Serialize(w io.Writer) (err error) {
if len(sig.outSubpackets) == 0 {
sig.outSubpackets = sig.rawSubpackets
}
if sig.RSASignature.bytes == nil &&
sig.DSASigR.bytes == nil &&
sig.ECDSASigR.bytes == nil &&
sig.EdDSASigR.bytes == nil {
return errors.InvalidArgumentError("Signature: need to call Sign, SignUserId or SignKey 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)
case PubKeyAlgoEdDSA:
sigLength = 2 + len(sig.EdDSASigR.bytes)
sigLength += 2 + len(sig.EdDSASigS.bytes)
case PubKeyAlgoECDSA:
sigLength = 2 + len(sig.ECDSASigR.bytes)
sigLength += 2 + len(sig.ECDSASigS.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)
case PubKeyAlgoEdDSA:
err = writeMPIs(w, sig.EdDSASigR, sig.EdDSASigS)
case PubKeyAlgoECDSA:
err = writeMPIs(w, sig.ECDSASigR, sig.ECDSASigS)
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)
binary.BigEndian.PutUint32(creationTime, uint32(sig.CreationTime.Unix()))
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})
}
if sig.SigLifetimeSecs != nil && *sig.SigLifetimeSecs != 0 {
sigLifetime := make([]byte, 4)
binary.BigEndian.PutUint32(sigLifetime, *sig.SigLifetimeSecs)
subpackets = append(subpackets, outputSubpacket{true, signatureExpirationSubpacket, true, sigLifetime})
}
// Key flags may only appear in self-signatures or certification signatures.
if sig.FlagsValid {
subpackets = append(subpackets, outputSubpacket{true, keyFlagsSubpacket, false, []byte{sig.GetKeyFlags().BitField}})
}
// The following subpackets may only appear in self-signatures
if sig.KeyLifetimeSecs != nil && *sig.KeyLifetimeSecs != 0 {
keyLifetime := make([]byte, 4)
binary.BigEndian.PutUint32(keyLifetime, *sig.KeyLifetimeSecs)
subpackets = append(subpackets, outputSubpacket{true, keyExpirationSubpacket, true, keyLifetime})
}
if sig.IsPrimaryId != nil && *sig.IsPrimaryId {
subpackets = append(subpackets, outputSubpacket{true, primaryUserIdSubpacket, false, []byte{1}})
}
if len(sig.PreferredSymmetric) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefSymmetricAlgosSubpacket, false, sig.PreferredSymmetric})
}
if len(sig.PreferredHash) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefHashAlgosSubpacket, false, sig.PreferredHash})
}
if len(sig.PreferredCompression) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefCompressionSubpacket, false, sig.PreferredCompression})
}
return
}
func (sig *Signature) GetKeyFlags() (ret KeyFlagBits) {
if !sig.FlagsValid {
return ret
}
ret.Valid = true
if sig.FlagCertify {
ret.BitField |= KeyFlagCertify
}
if sig.FlagSign {
ret.BitField |= KeyFlagSign
}
if sig.FlagEncryptCommunications {
ret.BitField |= KeyFlagEncryptCommunications
}
if sig.FlagEncryptStorage {
ret.BitField |= KeyFlagEncryptStorage
}
return ret
}
func (f *KeyFlagBits) HasFlagCertify() bool {
return f.BitField&KeyFlagCertify != 0
}
func (f *KeyFlagBits) HasFlagSign() bool {
return f.BitField&KeyFlagSign != 0
}
func (f *KeyFlagBits) HasFlagEncryptCommunications() bool {
return f.BitField&KeyFlagEncryptCommunications != 0
}
func (f *KeyFlagBits) HasFlagEncryptStorage() bool {
return f.BitField&KeyFlagEncryptStorage != 0
}
func (f *KeyFlagBits) Merge(other KeyFlagBits) {
if other.Valid {
f.Valid = true
f.BitField |= other.BitField
}
}

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// Copyright 2013 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"
"encoding/binary"
"fmt"
"io"
"strconv"
"time"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/openpgp/s2k"
)
// SignatureV3 represents older version 3 signatures. These signatures are less secure
// than version 4 and should not be used to create new signatures. They are included
// here for backwards compatibility to read and validate with older key material.
// See RFC 4880, section 5.2.2.
type SignatureV3 struct {
SigType SignatureType
CreationTime time.Time
IssuerKeyId uint64
PubKeyAlgo PublicKeyAlgorithm
Hash crypto.Hash
HashTag [2]byte
RSASignature parsedMPI
DSASigR, DSASigS parsedMPI
}
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
}
// 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
}

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// 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 (
"bytes"
"crypto/cipher"
"io"
"strconv"
"github.com/keybase/go-crypto/openpgp/errors"
"github.com/keybase/go-crypto/openpgp/s2k"
)
// This is the largest session key that we'll support. Since no 512-bit cipher
// has even been seriously used, this is comfortably large.
const maxSessionKeySizeInBytes = 64
// SymmetricKeyEncrypted represents a passphrase protected session key. See RFC
// 4880, section 5.3.
type SymmetricKeyEncrypted struct {
CipherFunc CipherFunction
s2k func(out, in []byte)
encryptedKey []byte
}
const symmetricKeyEncryptedVersion = 4
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
}
if ske.s2k == nil {
return errors.UnsupportedError("can't use dummy S2K for symmetric key encryption")
}
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
}
// 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
}
// 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
}

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// 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/cipher"
"crypto/sha1"
"crypto/subtle"
"hash"
"io"
"strconv"
"github.com/keybase/go-crypto/openpgp/errors"
)
// SymmetricallyEncrypted represents a symmetrically encrypted byte string. The
// encrypted contents will consist of more OpenPGP packets. See RFC 4880,
// sections 5.7 and 5.13.
type SymmetricallyEncrypted struct {
MDC bool // true iff this is a type 18 packet and thus has an embedded MAC.
contents io.Reader
prefix []byte
}
const symmetricallyEncryptedVersion = 1
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
}
// 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
}
// seReader wraps an io.Reader with a no-op Close method.
type seReader struct {
in io.Reader
}
func (ser seReader) Read(buf []byte) (int, error) {
return ser.in.Read(buf)
}
func (ser seReader) Close() error {
return nil
}
const mdcTrailerSize = 1 /* tag byte */ + 1 /* length byte */ + sha1.Size
// An seMDCReader wraps an io.Reader, maintains a running hash and keeps hold
// of the most recent 22 bytes (mdcTrailerSize). Upon EOF, those bytes form an
// MDC packet containing a hash of the previous contents which is checked
// against the running hash. See RFC 4880, section 5.13.
type seMDCReader struct {
in io.Reader
h hash.Hash
trailer [mdcTrailerSize]byte
scratch [mdcTrailerSize]byte
trailerUsed int
error bool
eof bool
}
func (ser *seMDCReader) Read(buf []byte) (n int, err error) {
if ser.error {
err = io.ErrUnexpectedEOF
return
}
if ser.eof {
err = io.EOF
return
}
// If we haven't yet filled the trailer buffer then we must do that
// first.
for ser.trailerUsed < mdcTrailerSize {
n, err = ser.in.Read(ser.trailer[ser.trailerUsed:])
ser.trailerUsed += n
if err == io.EOF {
if ser.trailerUsed != mdcTrailerSize {
n = 0
err = io.ErrUnexpectedEOF
ser.error = true
return
}
ser.eof = true
n = 0
return
}
if err != nil {
n = 0
return
}
}
// If it's a short read then we read into a temporary buffer and shift
// the data into the caller's buffer.
if len(buf) <= mdcTrailerSize {
n, err = readFull(ser.in, ser.scratch[:len(buf)])
copy(buf, ser.trailer[:n])
ser.h.Write(buf[:n])
copy(ser.trailer[:], ser.trailer[n:])
copy(ser.trailer[mdcTrailerSize-n:], ser.scratch[:])
if n < len(buf) {
ser.eof = true
err = io.EOF
}
return
}
n, err = ser.in.Read(buf[mdcTrailerSize:])
copy(buf, ser.trailer[:])
ser.h.Write(buf[:n])
copy(ser.trailer[:], buf[n:])
if err == io.EOF {
ser.eof = true
}
return
}
// This is a new-format packet tag byte for a type 19 (MDC) packet.
const mdcPacketTagByte = byte(0x80) | 0x40 | 19
func (ser *seMDCReader) Close() error {
if ser.error {
return errors.SignatureError("error during reading")
}
for !ser.eof {
// We haven't seen EOF so we need to read to the end
var buf [1024]byte
_, err := ser.Read(buf[:])
if err == io.EOF {
break
}
if err != nil {
return errors.SignatureError("error during reading")
}
}
if ser.trailer[0] != mdcPacketTagByte || ser.trailer[1] != sha1.Size {
return errors.SignatureError("MDC packet not found")
}
ser.h.Write(ser.trailer[:2])
final := ser.h.Sum(nil)
if subtle.ConstantTimeCompare(final, ser.trailer[2:]) != 1 {
return errors.SignatureError("hash mismatch")
}
return nil
}
// An seMDCWriter writes through to an io.WriteCloser while maintains a running
// hash of the data written. On close, it emits an MDC packet containing the
// running hash.
type seMDCWriter struct {
w io.WriteCloser
h hash.Hash
}
func (w *seMDCWriter) Write(buf []byte) (n int, err error) {
w.h.Write(buf)
return w.w.Write(buf)
}
func (w *seMDCWriter) Close() (err error) {
var buf [mdcTrailerSize]byte
buf[0] = mdcPacketTagByte
buf[1] = sha1.Size
w.h.Write(buf[:2])
digest := w.h.Sum(nil)
copy(buf[2:], digest)
_, err = w.w.Write(buf[:])
if err != nil {
return
}
return w.w.Close()
}
// noOpCloser is like an ioutil.NopCloser, but for an io.Writer.
type noOpCloser struct {
w io.Writer
}
func (c noOpCloser) Write(data []byte) (n int, err error) {
return c.w.Write(data)
}
func (c noOpCloser) Close() error {
return nil
}
// SerializeSymmetricallyEncrypted serializes a symmetrically encrypted packet
// to w and returns a WriteCloser to which the to-be-encrypted packets can be
// written.
// If config is nil, sensible defaults will be used.
func SerializeSymmetricallyEncrypted(w io.Writer, c CipherFunction, key []byte, config *Config) (contents io.WriteCloser, err error) {
if c.KeySize() != len(key) {
return nil, errors.InvalidArgumentError("SymmetricallyEncrypted.Serialize: bad key length")
}
writeCloser := noOpCloser{w}
ciphertext, err := serializeStreamHeader(writeCloser, packetTypeSymmetricallyEncryptedMDC)
if err != nil {
return
}
_, err = ciphertext.Write([]byte{symmetricallyEncryptedVersion})
if err != nil {
return
}
block := c.new(key)
blockSize := block.BlockSize()
iv := make([]byte, blockSize)
_, err = config.Random().Read(iv)
if err != nil {
return
}
s, prefix := NewOCFBEncrypter(block, iv, OCFBNoResync)
_, err = ciphertext.Write(prefix)
if err != nil {
return
}
plaintext := cipher.StreamWriter{S: s, W: ciphertext}
h := sha1.New()
h.Write(iv)
h.Write(iv[blockSize-2:])
contents = &seMDCWriter{w: plaintext, h: h}
return
}

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// Copyright 2013 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 (
"bytes"
"image"
"image/jpeg"
"io"
"io/ioutil"
)
const UserAttrImageSubpacket = 1
// UserAttribute is capable of storing other types of data about a user
// beyond name, email and a text comment. In practice, user attributes are typically used
// to store a signed thumbnail photo JPEG image of the user.
// See RFC 4880, section 5.12.
type UserAttribute struct {
Contents []*OpaqueSubpacket
}
// NewUserAttributePhoto creates a user attribute packet
// containing the given images.
func NewUserAttributePhoto(photos ...image.Image) (uat *UserAttribute, err error) {
uat = new(UserAttribute)
for _, photo := range photos {
var buf bytes.Buffer
// RFC 4880, Section 5.12.1.
data := []byte{
0x10, 0x00, // Little-endian image header length (16 bytes)
0x01, // Image header version 1
0x01, // JPEG
0, 0, 0, 0, // 12 reserved octets, must be all zero.
0, 0, 0, 0,
0, 0, 0, 0}
if _, err = buf.Write(data); err != nil {
return
}
if err = jpeg.Encode(&buf, photo, nil); err != nil {
return
}
uat.Contents = append(uat.Contents, &OpaqueSubpacket{
SubType: UserAttrImageSubpacket,
Contents: buf.Bytes()})
}
return
}
// NewUserAttribute creates a new user attribute packet containing the given subpackets.
func NewUserAttribute(contents ...*OpaqueSubpacket) *UserAttribute {
return &UserAttribute{Contents: contents}
}
func (uat *UserAttribute) parse(r io.Reader) (err error) {
// RFC 4880, section 5.13
b, err := ioutil.ReadAll(r)
if err != nil {
return
}
uat.Contents, err = OpaqueSubpackets(b)
return
}
// Serialize marshals the user attribute to w in the form of an OpenPGP packet, including
// header.
func (uat *UserAttribute) Serialize(w io.Writer) (err error) {
var buf bytes.Buffer
for _, sp := range uat.Contents {
sp.Serialize(&buf)
}
if err = serializeHeader(w, packetTypeUserAttribute, buf.Len()); err != nil {
return err
}
_, err = w.Write(buf.Bytes())
return
}
// ImageData returns zero or more byte slices, each containing
// JPEG File Interchange Format (JFIF), for each photo in the
// the user attribute packet.
func (uat *UserAttribute) ImageData() (imageData [][]byte) {
for _, sp := range uat.Contents {
if sp.SubType == UserAttrImageSubpacket && len(sp.Contents) > 16 {
imageData = append(imageData, sp.Contents[16:])
}
}
return
}

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// 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 (
"io"
"io/ioutil"
"strings"
)
// UserId contains text that is intended to represent the name and email
// address of the key holder. See RFC 4880, section 5.11. By convention, this
// takes the form "Full Name (Comment) <email@example.com>"
type UserId struct {
Id string // By convention, this takes the form "Full Name (Comment) <email@example.com>" which is split out in the fields below.
Name, Comment, Email string
}
func hasInvalidCharacters(s string) bool {
for _, c := range s {
switch c {
case '(', ')', '<', '>', 0:
return true
}
}
return false
}
// NewUserId returns a UserId or nil if any of the arguments contain invalid
// characters. The invalid characters are '\x00', '(', ')', '<' and '>'
func NewUserId(name, comment, email string) *UserId {
// RFC 4880 doesn't deal with the structure of userid strings; the
// name, comment and email form is just a convention. However, there's
// no convention about escaping the metacharacters and GPG just refuses
// to create user ids where, say, the name contains a '('. We mirror
// this behaviour.
if hasInvalidCharacters(name) || hasInvalidCharacters(comment) || hasInvalidCharacters(email) {
return nil
}
uid := new(UserId)
uid.Name, uid.Comment, uid.Email = name, comment, email
uid.Id = name
if len(comment) > 0 {
if len(uid.Id) > 0 {
uid.Id += " "
}
uid.Id += "("
uid.Id += comment
uid.Id += ")"
}
if len(email) > 0 {
if len(uid.Id) > 0 {
uid.Id += " "
}
uid.Id += "<"
uid.Id += email
uid.Id += ">"
}
return uid
}
func (uid *UserId) parse(r io.Reader) (err error) {
// RFC 4880, section 5.11
b, err := ioutil.ReadAll(r)
if err != nil {
return
}
uid.Id = string(b)
uid.Name, uid.Comment, uid.Email = parseUserId(uid.Id)
return
}
// Serialize marshals uid to w in the form of an OpenPGP packet, including
// header.
func (uid *UserId) Serialize(w io.Writer) error {
err := serializeHeader(w, packetTypeUserId, len(uid.Id))
if err != nil {
return err
}
_, err = w.Write([]byte(uid.Id))
return err
}
// parseUserId extracts the name, comment and email from a user id string that
// is formatted as "Full Name (Comment) <email@example.com>".
func parseUserId(id string) (name, comment, email string) {
var n, c, e struct {
start, end int
}
var state int
for offset, rune := range id {
switch state {
case 0:
// Entering name
n.start = offset
state = 1
fallthrough
case 1:
// In name
if rune == '(' {
state = 2
n.end = offset
} else if rune == '<' {
state = 5
n.end = offset
}
case 2:
// Entering comment
c.start = offset
state = 3
fallthrough
case 3:
// In comment
if rune == ')' {
state = 4
c.end = offset
}
case 4:
// Between comment and email
if rune == '<' {
state = 5
}
case 5:
// Entering email
e.start = offset
state = 6
fallthrough
case 6:
// In email
if rune == '>' {
state = 7
e.end = offset
}
default:
// After email
}
}
switch state {
case 1:
// ended in the name
n.end = len(id)
case 3:
// ended in comment
c.end = len(id)
case 6:
// ended in email
e.end = len(id)
}
name = strings.TrimSpace(id[n.start:n.end])
comment = strings.TrimSpace(id[c.start:c.end])
email = strings.TrimSpace(id[e.start:e.end])
return
}