/usr/share/gocode/src/golang.org/x/crypto/openpgp/packet/signature_v3.go is in golang-golang-x-crypto-dev 1:0.0~git20170629.0.5ef0053-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 | // 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
}
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