-
-
Notifications
You must be signed in to change notification settings - Fork 152
/
pgp.go
261 lines (216 loc) · 6.82 KB
/
pgp.go
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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
package sign
import (
"bytes"
"crypto"
"errors"
"fmt"
"io"
"os"
"strconv"
"unicode"
"github.com/ProtonMail/go-crypto/openpgp"
"github.com/ProtonMail/go-crypto/openpgp/clearsign"
"github.com/ProtonMail/go-crypto/openpgp/packet"
"github.com/goreleaser/nfpm/v2"
)
// PGPSigner returns a PGP signer that creates a detached non-ASCII-armored
// signature and is compatible with rpmpack's signature API.
func PGPSigner(keyFile, passphrase string) func([]byte) ([]byte, error) {
return PGPSignerWithKeyID(keyFile, passphrase, nil)
}
// PGPSignerWithKeyID returns a PGP signer that creates a detached non-ASCII-armored
// signature and is compatible with rpmpack's signature API.
func PGPSignerWithKeyID(keyFile, passphrase string, hexKeyId *string) func([]byte) ([]byte, error) {
return func(data []byte) ([]byte, error) {
keyId, err := parseKeyID(hexKeyId)
if err != nil {
return nil, fmt.Errorf("%v is not a valid key id: %w", hexKeyId, err)
}
key, err := readSigningKey(keyFile, passphrase)
if err != nil {
return nil, &nfpm.ErrSigningFailure{Err: err}
}
var signature bytes.Buffer
err = openpgp.DetachSign(&signature, key, bytes.NewReader(data), &packet.Config{
SigningKeyId: keyId,
DefaultHash: crypto.SHA256,
})
if err != nil {
return nil, &nfpm.ErrSigningFailure{Err: err}
}
return signature.Bytes(), nil
}
}
// PGPArmoredDetachSign creates an ASCII-armored detached signature.
func PGPArmoredDetachSign(message io.Reader, keyFile, passphrase string) ([]byte, error) {
return PGPArmoredDetachSignWithKeyID(message, keyFile, passphrase, nil)
}
// PGPArmoredDetachSignWithKeyID creates an ASCII-armored detached signature.
func PGPArmoredDetachSignWithKeyID(message io.Reader, keyFile, passphrase string, hexKeyId *string) ([]byte, error) {
keyId, err := parseKeyID(hexKeyId)
if err != nil {
return nil, fmt.Errorf("%v is not a valid key id: %w", hexKeyId, err)
}
key, err := readSigningKey(keyFile, passphrase)
if err != nil {
return nil, fmt.Errorf("armored detach sign: %w", err)
}
var signature bytes.Buffer
err = openpgp.ArmoredDetachSign(&signature, key, message, &packet.Config{
SigningKeyId: keyId,
DefaultHash: crypto.SHA256,
})
if err != nil {
return nil, fmt.Errorf("armored detach sign: %w", err)
}
return signature.Bytes(), nil
}
func PGPClearSignWithKeyID(message io.Reader, keyFile, passphrase string, hexKeyId *string) ([]byte, error) {
keyId, err := parseKeyID(hexKeyId)
if err != nil {
return nil, fmt.Errorf("%v is not a valid key id: %w", hexKeyId, err)
}
key, err := readSigningKey(keyFile, passphrase)
if err != nil {
return nil, fmt.Errorf("clear sign: %w", err)
}
var signature bytes.Buffer
writeCloser, err := clearsign.Encode(&signature, key.PrivateKey, &packet.Config{
SigningKeyId: keyId,
DefaultHash: crypto.SHA256,
})
if err != nil {
return nil, fmt.Errorf("clear sign: %w", err)
}
if _, err := io.Copy(writeCloser, message); err != nil {
return nil, fmt.Errorf("clear sign: %w", err)
}
if err := writeCloser.Close(); err != nil {
return nil, fmt.Errorf("clear sign: %w", err)
}
return signature.Bytes(), nil
}
// PGPVerify is exported for use in tests and verifies an ASCII-armored or non-ASCII-armored
// signature using an ASCII-armored or non-ASCII-armored public key file. The signer
// identity is not explicitly checked, other that the obvious fact that the signer's key must
// be in the armoredPubKeyFile.
func PGPVerify(message io.Reader, signature []byte, armoredPubKeyFile string) error {
keyFileContent, err := os.ReadFile(armoredPubKeyFile)
if err != nil {
return fmt.Errorf("reading armored public key file: %w", err)
}
var keyring openpgp.EntityList
if isASCII(keyFileContent) {
keyring, err = openpgp.ReadArmoredKeyRing(bytes.NewReader(keyFileContent))
if err != nil {
return fmt.Errorf("decoding armored public key file: %w", err)
}
} else {
keyring, err = openpgp.ReadKeyRing(bytes.NewReader(keyFileContent))
if err != nil {
return fmt.Errorf("decoding public key file: %w", err)
}
}
if isASCII(signature) {
_, err = openpgp.CheckArmoredDetachedSignature(keyring, message, bytes.NewReader(signature), nil)
return err
}
_, err = openpgp.CheckDetachedSignature(keyring, message, bytes.NewReader(signature), nil)
return err
}
func PGPReadMessage(message []byte, armoredPubKeyFile string) error {
keyFileContent, err := os.ReadFile(armoredPubKeyFile)
if err != nil {
return fmt.Errorf("reading armored public key file: %w", err)
}
var keyring openpgp.EntityList
if isASCII(keyFileContent) {
keyring, err = openpgp.ReadArmoredKeyRing(bytes.NewReader(keyFileContent))
if err != nil {
return fmt.Errorf("decoding armored public key file: %w", err)
}
} else {
keyring, err = openpgp.ReadKeyRing(bytes.NewReader(keyFileContent))
if err != nil {
return fmt.Errorf("decoding public key file: %w", err)
}
}
block, _ := clearsign.Decode(message)
_, err = block.VerifySignature(keyring, nil)
return err
}
func parseKeyID(hexKeyId *string) (uint64, error) {
if hexKeyId == nil || *hexKeyId == "" {
return 0, nil
}
result, err := strconv.ParseUint(*hexKeyId, 16, 64)
if err != nil {
return 0, err
}
return result, nil
}
var (
errMoreThanOneKey = errors.New("more than one signing key in keyring")
errNoKeys = errors.New("no signing key in keyring")
errNoPassword = errors.New("key is encrypted but no passphrase was provided")
)
func readSigningKey(keyFile, passphrase string) (*openpgp.Entity, error) {
fileContent, err := os.ReadFile(keyFile)
if err != nil {
return nil, fmt.Errorf("reading PGP key file: %w", err)
}
var entityList openpgp.EntityList
if isASCII(fileContent) {
entityList, err = openpgp.ReadArmoredKeyRing(bytes.NewReader(fileContent))
if err != nil {
return nil, fmt.Errorf("decoding armored PGP keyring: %w", err)
}
} else {
entityList, err = openpgp.ReadKeyRing(bytes.NewReader(fileContent))
if err != nil {
return nil, fmt.Errorf("decoding PGP keyring: %w", err)
}
}
var key *openpgp.Entity
for _, candidate := range entityList {
if candidate.PrivateKey == nil {
continue
}
if !candidate.PrivateKey.CanSign() {
continue
}
if key != nil {
return nil, errMoreThanOneKey
}
key = candidate
}
if key == nil {
return nil, errNoKeys
}
if key.PrivateKey.Encrypted {
if passphrase == "" {
return nil, errNoPassword
}
pw := []byte(passphrase)
err = key.PrivateKey.Decrypt(pw)
if err != nil {
return nil, fmt.Errorf("decrypt secret signing key: %w", err)
}
for _, sub := range key.Subkeys {
if sub.PrivateKey != nil {
if err := sub.PrivateKey.Decrypt(pw); err != nil {
return nil, fmt.Errorf("gopenpgp: error in unlocking sub key: %w", err)
}
}
}
}
return key, nil
}
func isASCII(s []byte) bool {
for i := 0; i < len(s); i++ {
if s[i] > unicode.MaxASCII {
return false
}
}
return true
}