diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/openpgp/packet/signature_v3.go')
-rw-r--r-- | vendor/golang.org/x/crypto/openpgp/packet/signature_v3.go | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/openpgp/packet/signature_v3.go b/vendor/golang.org/x/crypto/openpgp/packet/signature_v3.go new file mode 100644 index 000000000..6edff8893 --- /dev/null +++ b/vendor/golang.org/x/crypto/openpgp/packet/signature_v3.go @@ -0,0 +1,146 @@ +// 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" + + "golang.org/x/crypto/openpgp/errors" + "golang.org/x/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 +} |