gpg-interface.c: support getting key fingerprint via %GF format
[git/git.git] / gpg-interface.c
CommitLineData
2f47eae2 1#include "cache.h"
b2141fc1 2#include "config.h"
2f47eae2
JH
3#include "run-command.h"
4#include "strbuf.h"
5#include "gpg-interface.h"
6#include "sigchain.h"
4322353b 7#include "tempfile.h"
2f47eae2
JH
8
9static char *configured_signing_key;
58af57e1
HS
10struct gpg_format {
11 const char *name;
12 const char *program;
13 const char **verify_args;
14 const char **sigs;
15};
16
17static const char *openpgp_verify_args[] = {
18 "--keyid-format=long",
19 NULL
20};
21static const char *openpgp_sigs[] = {
22 "-----BEGIN PGP SIGNATURE-----",
23 "-----BEGIN PGP MESSAGE-----",
24 NULL
25};
26
1e7adb97
HS
27static const char *x509_verify_args[] = {
28 NULL
29};
30static const char *x509_sigs[] = {
31 "-----BEGIN SIGNED MESSAGE-----",
32 NULL
33};
34
58af57e1
HS
35static struct gpg_format gpg_format[] = {
36 { .name = "openpgp", .program = "gpg",
37 .verify_args = openpgp_verify_args,
38 .sigs = openpgp_sigs
39 },
1e7adb97
HS
40 { .name = "x509", .program = "gpgsm",
41 .verify_args = x509_verify_args,
42 .sigs = x509_sigs
43 },
58af57e1
HS
44};
45
46static struct gpg_format *use_format = &gpg_format[0];
2f47eae2 47
58af57e1
HS
48static struct gpg_format *get_format_by_name(const char *str)
49{
50 int i;
51
52 for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
53 if (!strcmp(gpg_format[i].name, str))
54 return gpg_format + i;
55 return NULL;
56}
57
58static struct gpg_format *get_format_by_sig(const char *sig)
59{
60 int i, j;
61
62 for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
63 for (j = 0; gpg_format[i].sigs[j]; j++)
64 if (starts_with(sig, gpg_format[i].sigs[j]))
65 return gpg_format + i;
66 return NULL;
67}
d7c67668 68
01e57b5d
MG
69void signature_check_clear(struct signature_check *sigc)
70{
88ce3ef6
ÆAB
71 FREE_AND_NULL(sigc->payload);
72 FREE_AND_NULL(sigc->gpg_output);
73 FREE_AND_NULL(sigc->gpg_status);
74 FREE_AND_NULL(sigc->signer);
75 FREE_AND_NULL(sigc->key);
3daaaabe 76 FREE_AND_NULL(sigc->fingerprint);
01e57b5d
MG
77}
78
da6cf1b3
MG
79/* An exclusive status -- only one of them can appear in output */
80#define GPG_STATUS_EXCLUSIVE (1<<0)
0b11a84e
MG
81/* The status includes key identifier */
82#define GPG_STATUS_KEYID (1<<1)
83/* The status includes user identifier */
84#define GPG_STATUS_UID (1<<2)
3daaaabe
MG
85/* The status includes key fingerprints */
86#define GPG_STATUS_FINGERPRINT (1<<3)
0b11a84e
MG
87
88/* Short-hand for standard exclusive *SIG status with keyid & UID */
89#define GPG_STATUS_STDSIG (GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID|GPG_STATUS_UID)
da6cf1b3 90
a50e7ca3
JH
91static struct {
92 char result;
93 const char *check;
da6cf1b3 94 unsigned int flags;
a50e7ca3 95} sigcheck_gpg_status[] = {
0b11a84e
MG
96 { 'G', "GOODSIG ", GPG_STATUS_STDSIG },
97 { 'B', "BADSIG ", GPG_STATUS_STDSIG },
da6cf1b3
MG
98 { 'U', "TRUST_NEVER", 0 },
99 { 'U', "TRUST_UNDEFINED", 0 },
0b11a84e
MG
100 { 'E', "ERRSIG ", GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID },
101 { 'X', "EXPSIG ", GPG_STATUS_STDSIG },
102 { 'Y', "EXPKEYSIG ", GPG_STATUS_STDSIG },
103 { 'R', "REVKEYSIG ", GPG_STATUS_STDSIG },
3daaaabe 104 { 0, "VALIDSIG ", GPG_STATUS_FINGERPRINT },
a50e7ca3
JH
105};
106
fbd0f166 107static void parse_gpg_output(struct signature_check *sigc)
a50e7ca3
JH
108{
109 const char *buf = sigc->gpg_status;
da6cf1b3 110 const char *line, *next;
a50e7ca3 111 int i;
da6cf1b3
MG
112 int seen_exclusive_status = 0;
113
114 /* Iterate over all lines */
115 for (line = buf; *line; line = strchrnul(line+1, '\n')) {
116 while (*line == '\n')
117 line++;
118 /* Skip lines that don't start with GNUPG status */
119 if (!skip_prefix(line, "[GNUPG:] ", &line))
120 continue;
121
122 /* Iterate over all search strings */
123 for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
124 if (skip_prefix(line, sigcheck_gpg_status[i].check, &line)) {
125 if (sigcheck_gpg_status[i].flags & GPG_STATUS_EXCLUSIVE) {
126 if (++seen_exclusive_status > 1)
127 goto found_duplicate_status;
128 }
129
3daaaabe
MG
130 if (sigcheck_gpg_status[i].result)
131 sigc->result = sigcheck_gpg_status[i].result;
0b11a84e
MG
132 /* Do we have key information? */
133 if (sigcheck_gpg_status[i].flags & GPG_STATUS_KEYID) {
da6cf1b3
MG
134 next = strchrnul(line, ' ');
135 free(sigc->key);
136 sigc->key = xmemdupz(line, next - line);
0b11a84e
MG
137 /* Do we have signer information? */
138 if (*next && (sigcheck_gpg_status[i].flags & GPG_STATUS_UID)) {
da6cf1b3
MG
139 line = next + 1;
140 next = strchrnul(line, '\n');
141 free(sigc->signer);
142 sigc->signer = xmemdupz(line, next - line);
143 }
144 }
3daaaabe
MG
145 /* Do we have fingerprint? */
146 if (sigcheck_gpg_status[i].flags & GPG_STATUS_FINGERPRINT) {
147 next = strchrnul(line, ' ');
148 free(sigc->fingerprint);
149 sigc->fingerprint = xmemdupz(line, next - line);
150 }
da6cf1b3
MG
151
152 break;
661a1806 153 }
a50e7ca3
JH
154 }
155 }
da6cf1b3
MG
156 return;
157
158found_duplicate_status:
159 /*
160 * GOODSIG, BADSIG etc. can occur only once for each signature.
161 * Therefore, if we had more than one then we're dealing with multiple
162 * signatures. We don't support them currently, and they're rather
163 * hard to create, so something is likely fishy and we should reject
164 * them altogether.
165 */
166 sigc->result = 'E';
167 /* Clear partial data to avoid confusion */
3daaaabe 168 FREE_AND_NULL(sigc->fingerprint);
da6cf1b3
MG
169 FREE_AND_NULL(sigc->signer);
170 FREE_AND_NULL(sigc->key);
a50e7ca3
JH
171}
172
434060ec 173int check_signature(const char *payload, size_t plen, const char *signature,
a4cc18f2 174 size_t slen, struct signature_check *sigc)
175{
176 struct strbuf gpg_output = STRBUF_INIT;
177 struct strbuf gpg_status = STRBUF_INIT;
178 int status;
179
180 sigc->result = 'N';
181
182 status = verify_signed_buffer(payload, plen, signature, slen,
183 &gpg_output, &gpg_status);
184 if (status && !gpg_output.len)
185 goto out;
186 sigc->payload = xmemdupz(payload, plen);
187 sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
188 sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
189 parse_gpg_output(sigc);
4e5dc9ca 190 status |= sigc->result != 'G' && sigc->result != 'U';
a4cc18f2 191
192 out:
193 strbuf_release(&gpg_status);
194 strbuf_release(&gpg_output);
434060ec 195
4e5dc9ca 196 return !!status;
a4cc18f2 197}
198
ca194d50 199void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
200{
aeff29dd 201 const char *output = flags & GPG_VERIFY_RAW ?
202 sigc->gpg_status : sigc->gpg_output;
203
ca194d50 204 if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
205 fputs(sigc->payload, stdout);
206
aeff29dd 207 if (output)
208 fputs(output, stderr);
ca194d50 209}
210
e6fa6cde 211size_t parse_signature(const char *buf, size_t size)
d7c67668 212{
d7c67668 213 size_t len = 0;
8b44b2be
JK
214 size_t match = size;
215 while (len < size) {
216 const char *eol;
217
58af57e1 218 if (get_format_by_sig(buf + len))
8b44b2be
JK
219 match = len;
220
221 eol = memchr(buf + len, '\n', size - len);
d7c67668
JH
222 len += eol ? eol - (buf + len) + 1 : size - len;
223 }
8b44b2be 224 return match;
d7c67668
JH
225}
226
2f47eae2
JH
227void set_signing_key(const char *key)
228{
229 free(configured_signing_key);
230 configured_signing_key = xstrdup(key);
231}
232
233int git_gpg_config(const char *var, const char *value, void *cb)
234{
58af57e1
HS
235 struct gpg_format *fmt = NULL;
236 char *fmtname = NULL;
237
2f47eae2 238 if (!strcmp(var, "user.signingkey")) {
1b0eeec3
JK
239 if (!value)
240 return config_error_nonbool(var);
0c5e70f0 241 set_signing_key(value);
1b0eeec3 242 return 0;
0c5e70f0 243 }
1b0eeec3 244
57a8dd75
HS
245 if (!strcmp(var, "gpg.format")) {
246 if (!value)
247 return config_error_nonbool(var);
58af57e1
HS
248 fmt = get_format_by_name(value);
249 if (!fmt)
57a8dd75
HS
250 return error("unsupported value for %s: %s",
251 var, value);
58af57e1
HS
252 use_format = fmt;
253 return 0;
57a8dd75
HS
254 }
255
b02f51b1 256 if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
58af57e1
HS
257 fmtname = "openpgp";
258
1e7adb97
HS
259 if (!strcmp(var, "gpg.x509.program"))
260 fmtname = "x509";
261
58af57e1
HS
262 if (fmtname) {
263 fmt = get_format_by_name(fmtname);
264 return git_config_string(&fmt->program, var, value);
2f47eae2 265 }
1b0eeec3 266
2f47eae2
JH
267 return 0;
268}
269
270const char *get_signing_key(void)
271{
272 if (configured_signing_key)
273 return configured_signing_key;
f9bc573f 274 return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
2f47eae2
JH
275}
276
2f47eae2
JH
277int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
278{
d3180279 279 struct child_process gpg = CHILD_PROCESS_INIT;
0581b546 280 int ret;
2f47eae2 281 size_t i, j, bottom;
efee9553 282 struct strbuf gpg_status = STRBUF_INIT;
2f47eae2 283
aedb5dc3 284 argv_array_pushl(&gpg.args,
58af57e1 285 use_format->program,
efee9553 286 "--status-fd=2",
aedb5dc3
JK
287 "-bsau", signing_key,
288 NULL);
2f47eae2 289
0581b546 290 bottom = signature->len;
2f47eae2
JH
291
292 /*
293 * When the username signingkey is bad, program could be terminated
294 * because gpg exits without reading and then write gets SIGPIPE.
295 */
296 sigchain_push(SIGPIPE, SIG_IGN);
0581b546 297 ret = pipe_command(&gpg, buffer->buf, buffer->len,
efee9553 298 signature, 1024, &gpg_status, 0);
2f47eae2
JH
299 sigchain_pop(SIGPIPE);
300
efee9553
MG
301 ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
302 strbuf_release(&gpg_status);
303 if (ret)
2f47eae2
JH
304 return error(_("gpg failed to sign the data"));
305
306 /* Strip CR from the line endings, in case we are on Windows. */
307 for (i = j = bottom; i < signature->len; i++)
308 if (signature->buf[i] != '\r') {
309 if (i != j)
310 signature->buf[j] = signature->buf[i];
311 j++;
312 }
313 strbuf_setlen(signature, j);
314
315 return 0;
316}
317
2f47eae2
JH
318int verify_signed_buffer(const char *payload, size_t payload_size,
319 const char *signature, size_t signature_size,
9cc4ac8f 320 struct strbuf *gpg_output, struct strbuf *gpg_status)
2f47eae2 321{
d3180279 322 struct child_process gpg = CHILD_PROCESS_INIT;
58af57e1 323 struct gpg_format *fmt;
076aa2cb
JK
324 struct tempfile *temp;
325 int ret;
b60b7566 326 struct strbuf buf = STRBUF_INIT;
2f47eae2 327
076aa2cb
JK
328 temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
329 if (!temp)
4322353b 330 return error_errno(_("could not create temporary file"));
076aa2cb
JK
331 if (write_in_full(temp->fd, signature, signature_size) < 0 ||
332 close_tempfile_gently(temp) < 0) {
4322353b 333 error_errno(_("failed writing detached signature to '%s'"),
076aa2cb 334 temp->filename.buf);
4322353b
JK
335 delete_tempfile(&temp);
336 return -1;
337 }
2f47eae2 338
58af57e1
HS
339 fmt = get_format_by_sig(signature);
340 if (!fmt)
341 BUG("bad signature '%s'", signature);
342
343 argv_array_push(&gpg.args, fmt->program);
344 argv_array_pushv(&gpg.args, fmt->verify_args);
aedb5dc3 345 argv_array_pushl(&gpg.args,
aedb5dc3 346 "--status-fd=1",
076aa2cb 347 "--verify", temp->filename.buf, "-",
aedb5dc3 348 NULL);
2f47eae2 349
c752fcc8
JK
350 if (!gpg_status)
351 gpg_status = &buf;
b60b7566 352
0d2b664e
JK
353 sigchain_push(SIGPIPE, SIG_IGN);
354 ret = pipe_command(&gpg, payload, payload_size,
355 gpg_status, 0, gpg_output, 0);
d281b45d 356 sigchain_pop(SIGPIPE);
2f47eae2 357
4322353b 358 delete_tempfile(&temp);
2f47eae2 359
c752fcc8 360 ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
9cc4ac8f 361 strbuf_release(&buf); /* no matter it was used or not */
b60b7566 362
2f47eae2
JH
363 return ret;
364}