sign_buffer: use pipe_command
[git/git.git] / gpg-interface.c
CommitLineData
2f47eae2
JH
1#include "cache.h"
2#include "run-command.h"
3#include "strbuf.h"
4#include "gpg-interface.h"
5#include "sigchain.h"
4322353b 6#include "tempfile.h"
2f47eae2
JH
7
8static char *configured_signing_key;
0c5e70f0 9static const char *gpg_program = "gpg";
2f47eae2 10
d7c67668
JH
11#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
12#define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
13
01e57b5d
MG
14void signature_check_clear(struct signature_check *sigc)
15{
71c214c8 16 free(sigc->payload);
01e57b5d
MG
17 free(sigc->gpg_output);
18 free(sigc->gpg_status);
19 free(sigc->signer);
20 free(sigc->key);
71c214c8 21 sigc->payload = NULL;
01e57b5d
MG
22 sigc->gpg_output = NULL;
23 sigc->gpg_status = NULL;
24 sigc->signer = NULL;
25 sigc->key = NULL;
26}
27
a50e7ca3
JH
28static struct {
29 char result;
30 const char *check;
31} sigcheck_gpg_status[] = {
32 { 'G', "\n[GNUPG:] GOODSIG " },
33 { 'B', "\n[GNUPG:] BADSIG " },
34 { 'U', "\n[GNUPG:] TRUST_NEVER" },
35 { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
36};
37
38void parse_gpg_output(struct signature_check *sigc)
39{
40 const char *buf = sigc->gpg_status;
41 int i;
42
43 /* Iterate over all search strings */
44 for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
45 const char *found, *next;
46
47 if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
48 found = strstr(buf, sigcheck_gpg_status[i].check);
49 if (!found)
50 continue;
51 found += strlen(sigcheck_gpg_status[i].check);
52 }
53 sigc->result = sigcheck_gpg_status[i].result;
54 /* The trust messages are not followed by key/signer information */
55 if (sigc->result != 'U') {
56 sigc->key = xmemdupz(found, 16);
57 found += 17;
58 next = strchrnul(found, '\n');
59 sigc->signer = xmemdupz(found, next - found);
60 }
61 }
62}
63
434060ec 64int check_signature(const char *payload, size_t plen, const char *signature,
a4cc18f2 65 size_t slen, struct signature_check *sigc)
66{
67 struct strbuf gpg_output = STRBUF_INIT;
68 struct strbuf gpg_status = STRBUF_INIT;
69 int status;
70
71 sigc->result = 'N';
72
73 status = verify_signed_buffer(payload, plen, signature, slen,
74 &gpg_output, &gpg_status);
75 if (status && !gpg_output.len)
76 goto out;
77 sigc->payload = xmemdupz(payload, plen);
78 sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
79 sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
80 parse_gpg_output(sigc);
81
82 out:
83 strbuf_release(&gpg_status);
84 strbuf_release(&gpg_output);
434060ec 85
86 return sigc->result != 'G' && sigc->result != 'U';
a4cc18f2 87}
88
ca194d50 89void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
90{
aeff29dd 91 const char *output = flags & GPG_VERIFY_RAW ?
92 sigc->gpg_status : sigc->gpg_output;
93
ca194d50 94 if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
95 fputs(sigc->payload, stdout);
96
aeff29dd 97 if (output)
98 fputs(output, stderr);
ca194d50 99}
100
d7c67668
JH
101/*
102 * Look at GPG signed content (e.g. a signed tag object), whose
103 * payload is followed by a detached signature on it. Return the
104 * offset where the embedded detached signature begins, or the end of
105 * the data when there is no such signature.
106 */
107size_t parse_signature(const char *buf, unsigned long size)
108{
109 char *eol;
110 size_t len = 0;
111 while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
112 !starts_with(buf + len, PGP_MESSAGE)) {
113 eol = memchr(buf + len, '\n', size - len);
114 len += eol ? eol - (buf + len) + 1 : size - len;
115 }
116 return len;
117}
118
2f47eae2
JH
119void set_signing_key(const char *key)
120{
121 free(configured_signing_key);
122 configured_signing_key = xstrdup(key);
123}
124
125int git_gpg_config(const char *var, const char *value, void *cb)
126{
127 if (!strcmp(var, "user.signingkey")) {
0c5e70f0
JH
128 set_signing_key(value);
129 }
130 if (!strcmp(var, "gpg.program")) {
2f47eae2
JH
131 if (!value)
132 return config_error_nonbool(var);
0c5e70f0 133 gpg_program = xstrdup(value);
2f47eae2
JH
134 }
135 return 0;
136}
137
138const char *get_signing_key(void)
139{
140 if (configured_signing_key)
141 return configured_signing_key;
f9bc573f 142 return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
2f47eae2
JH
143}
144
145/*
146 * Create a detached signature for the contents of "buffer" and append
147 * it after "signature"; "buffer" and "signature" can be the same
148 * strbuf instance, which would cause the detached signature appended
149 * at the end.
150 */
151int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
152{
d3180279 153 struct child_process gpg = CHILD_PROCESS_INIT;
0581b546 154 int ret;
2f47eae2
JH
155 size_t i, j, bottom;
156
aedb5dc3
JK
157 argv_array_pushl(&gpg.args,
158 gpg_program,
159 "-bsau", signing_key,
160 NULL);
2f47eae2 161
0581b546 162 bottom = signature->len;
2f47eae2
JH
163
164 /*
165 * When the username signingkey is bad, program could be terminated
166 * because gpg exits without reading and then write gets SIGPIPE.
167 */
168 sigchain_push(SIGPIPE, SIG_IGN);
0581b546
JK
169 ret = pipe_command(&gpg, buffer->buf, buffer->len,
170 signature, 1024, NULL, 0);
2f47eae2
JH
171 sigchain_pop(SIGPIPE);
172
0581b546 173 if (ret || signature->len == bottom)
2f47eae2
JH
174 return error(_("gpg failed to sign the data"));
175
176 /* Strip CR from the line endings, in case we are on Windows. */
177 for (i = j = bottom; i < signature->len; i++)
178 if (signature->buf[i] != '\r') {
179 if (i != j)
180 signature->buf[j] = signature->buf[i];
181 j++;
182 }
183 strbuf_setlen(signature, j);
184
185 return 0;
186}
187
188/*
189 * Run "gpg" to see if the payload matches the detached signature.
e3f55e07 190 * gpg_output, when set, receives the diagnostic output from GPG.
b60b7566 191 * gpg_status, when set, receives the status output from GPG.
2f47eae2
JH
192 */
193int verify_signed_buffer(const char *payload, size_t payload_size,
194 const char *signature, size_t signature_size,
9cc4ac8f 195 struct strbuf *gpg_output, struct strbuf *gpg_status)
2f47eae2 196{
d3180279 197 struct child_process gpg = CHILD_PROCESS_INIT;
4322353b 198 static struct tempfile temp;
2f47eae2 199 int fd, ret;
b60b7566 200 struct strbuf buf = STRBUF_INIT;
2f47eae2 201
4322353b 202 fd = mks_tempfile_t(&temp, ".git_vtag_tmpXXXXXX");
2f47eae2 203 if (fd < 0)
4322353b
JK
204 return error_errno(_("could not create temporary file"));
205 if (write_in_full(fd, signature, signature_size) < 0) {
206 error_errno(_("failed writing detached signature to '%s'"),
207 temp.filename.buf);
208 delete_tempfile(&temp);
209 return -1;
210 }
2f47eae2
JH
211 close(fd);
212
aedb5dc3
JK
213 argv_array_pushl(&gpg.args,
214 gpg_program,
215 "--status-fd=1",
4322353b 216 "--verify", temp.filename.buf, "-",
aedb5dc3 217 NULL);
2f47eae2 218
c752fcc8
JK
219 if (!gpg_status)
220 gpg_status = &buf;
b60b7566 221
0d2b664e
JK
222 sigchain_push(SIGPIPE, SIG_IGN);
223 ret = pipe_command(&gpg, payload, payload_size,
224 gpg_status, 0, gpg_output, 0);
d281b45d 225 sigchain_pop(SIGPIPE);
2f47eae2 226
4322353b 227 delete_tempfile(&temp);
2f47eae2 228
c752fcc8 229 ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
9cc4ac8f 230 strbuf_release(&buf); /* no matter it was used or not */
b60b7566 231
2f47eae2
JH
232 return ret;
233}