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author | Péter Szilágyi <peterke@gmail.com> | 2016-11-03 00:22:53 +0800 |
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committer | Péter Szilágyi <peterke@gmail.com> | 2016-11-03 16:32:57 +0800 |
commit | bad0de0dcbae82d96f68d1eec1701042d5dfa985 (patch) | |
tree | 7b6e585f47a0c4bb9f6e3a17d549ca1d0ddbd642 /vendor/golang.org/x/crypto/openpgp/packet/public_key_v3.go | |
parent | 3b62c145f8d699767e13770d1bb21d07c2ba9b46 (diff) | |
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vendor: pull in azure sdk and openpgp signer
Diffstat (limited to 'vendor/golang.org/x/crypto/openpgp/packet/public_key_v3.go')
-rw-r--r-- | vendor/golang.org/x/crypto/openpgp/packet/public_key_v3.go | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/openpgp/packet/public_key_v3.go b/vendor/golang.org/x/crypto/openpgp/packet/public_key_v3.go new file mode 100644 index 000000000..26337f5aa --- /dev/null +++ b/vendor/golang.org/x/crypto/openpgp/packet/public_key_v3.go @@ -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" + "crypto/rsa" + "encoding/binary" + "fmt" + "hash" + "io" + "math/big" + "strconv" + "time" + + "golang.org/x/crypto/openpgp/errors" +) + +// 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) > 3 { + err = errors.UnsupportedError("large public exponent") + return + } + rsa := &rsa.PublicKey{N: new(big.Int).SetBytes(pk.n.bytes)} + for i := 0; i < len(pk.e.bytes); i++ { + rsa.E <<= 8 + rsa.E |= int(pk.e.bytes[i]) + } + pk.PublicKey = rsa + return +} + +// 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 +} |