Merge branch 'jc/git-gui-has-maintainer'
[git/git.git] / gpg-interface.c
1 #include "cache.h"
2 #include "config.h"
3 #include "run-command.h"
4 #include "strbuf.h"
5 #include "gpg-interface.h"
6 #include "sigchain.h"
7 #include "tempfile.h"
8
9 static char *configured_signing_key;
10 struct gpg_format {
11 const char *name;
12 const char *program;
13 const char **verify_args;
14 const char **sigs;
15 };
16
17 static const char *openpgp_verify_args[] = {
18 "--keyid-format=long",
19 NULL
20 };
21 static const char *openpgp_sigs[] = {
22 "-----BEGIN PGP SIGNATURE-----",
23 "-----BEGIN PGP MESSAGE-----",
24 NULL
25 };
26
27 static const char *x509_verify_args[] = {
28 NULL
29 };
30 static const char *x509_sigs[] = {
31 "-----BEGIN SIGNED MESSAGE-----",
32 NULL
33 };
34
35 static struct gpg_format gpg_format[] = {
36 { .name = "openpgp", .program = "gpg",
37 .verify_args = openpgp_verify_args,
38 .sigs = openpgp_sigs
39 },
40 { .name = "x509", .program = "gpgsm",
41 .verify_args = x509_verify_args,
42 .sigs = x509_sigs
43 },
44 };
45
46 static struct gpg_format *use_format = &gpg_format[0];
47
48 static 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
58 static 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 }
68
69 void signature_check_clear(struct signature_check *sigc)
70 {
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);
76 FREE_AND_NULL(sigc->fingerprint);
77 FREE_AND_NULL(sigc->primary_key_fingerprint);
78 }
79
80 /* An exclusive status -- only one of them can appear in output */
81 #define GPG_STATUS_EXCLUSIVE (1<<0)
82 /* The status includes key identifier */
83 #define GPG_STATUS_KEYID (1<<1)
84 /* The status includes user identifier */
85 #define GPG_STATUS_UID (1<<2)
86 /* The status includes key fingerprints */
87 #define GPG_STATUS_FINGERPRINT (1<<3)
88
89 /* Short-hand for standard exclusive *SIG status with keyid & UID */
90 #define GPG_STATUS_STDSIG (GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID|GPG_STATUS_UID)
91
92 static struct {
93 char result;
94 const char *check;
95 unsigned int flags;
96 } sigcheck_gpg_status[] = {
97 { 'G', "GOODSIG ", GPG_STATUS_STDSIG },
98 { 'B', "BADSIG ", GPG_STATUS_STDSIG },
99 { 'U', "TRUST_NEVER", 0 },
100 { 'U', "TRUST_UNDEFINED", 0 },
101 { 'E', "ERRSIG ", GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID },
102 { 'X', "EXPSIG ", GPG_STATUS_STDSIG },
103 { 'Y', "EXPKEYSIG ", GPG_STATUS_STDSIG },
104 { 'R', "REVKEYSIG ", GPG_STATUS_STDSIG },
105 { 0, "VALIDSIG ", GPG_STATUS_FINGERPRINT },
106 };
107
108 static void parse_gpg_output(struct signature_check *sigc)
109 {
110 const char *buf = sigc->gpg_status;
111 const char *line, *next;
112 int i, j;
113 int seen_exclusive_status = 0;
114
115 /* Iterate over all lines */
116 for (line = buf; *line; line = strchrnul(line+1, '\n')) {
117 while (*line == '\n')
118 line++;
119 if (!*line)
120 break;
121
122 /* Skip lines that don't start with GNUPG status */
123 if (!skip_prefix(line, "[GNUPG:] ", &line))
124 continue;
125
126 /* Iterate over all search strings */
127 for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
128 if (skip_prefix(line, sigcheck_gpg_status[i].check, &line)) {
129 if (sigcheck_gpg_status[i].flags & GPG_STATUS_EXCLUSIVE) {
130 if (seen_exclusive_status++)
131 goto found_duplicate_status;
132 }
133
134 if (sigcheck_gpg_status[i].result)
135 sigc->result = sigcheck_gpg_status[i].result;
136 /* Do we have key information? */
137 if (sigcheck_gpg_status[i].flags & GPG_STATUS_KEYID) {
138 next = strchrnul(line, ' ');
139 free(sigc->key);
140 sigc->key = xmemdupz(line, next - line);
141 /* Do we have signer information? */
142 if (*next && (sigcheck_gpg_status[i].flags & GPG_STATUS_UID)) {
143 line = next + 1;
144 next = strchrnul(line, '\n');
145 free(sigc->signer);
146 sigc->signer = xmemdupz(line, next - line);
147 }
148 }
149 /* Do we have fingerprint? */
150 if (sigcheck_gpg_status[i].flags & GPG_STATUS_FINGERPRINT) {
151 next = strchrnul(line, ' ');
152 free(sigc->fingerprint);
153 sigc->fingerprint = xmemdupz(line, next - line);
154
155 /* Skip interim fields */
156 for (j = 9; j > 0; j--) {
157 if (!*next)
158 break;
159 line = next + 1;
160 next = strchrnul(line, ' ');
161 }
162
163 next = strchrnul(line, '\n');
164 free(sigc->primary_key_fingerprint);
165 sigc->primary_key_fingerprint = xmemdupz(line, next - line);
166 }
167
168 break;
169 }
170 }
171 }
172 return;
173
174 found_duplicate_status:
175 /*
176 * GOODSIG, BADSIG etc. can occur only once for each signature.
177 * Therefore, if we had more than one then we're dealing with multiple
178 * signatures. We don't support them currently, and they're rather
179 * hard to create, so something is likely fishy and we should reject
180 * them altogether.
181 */
182 sigc->result = 'E';
183 /* Clear partial data to avoid confusion */
184 FREE_AND_NULL(sigc->primary_key_fingerprint);
185 FREE_AND_NULL(sigc->fingerprint);
186 FREE_AND_NULL(sigc->signer);
187 FREE_AND_NULL(sigc->key);
188 }
189
190 int check_signature(const char *payload, size_t plen, const char *signature,
191 size_t slen, struct signature_check *sigc)
192 {
193 struct strbuf gpg_output = STRBUF_INIT;
194 struct strbuf gpg_status = STRBUF_INIT;
195 int status;
196
197 sigc->result = 'N';
198
199 status = verify_signed_buffer(payload, plen, signature, slen,
200 &gpg_output, &gpg_status);
201 if (status && !gpg_output.len)
202 goto out;
203 sigc->payload = xmemdupz(payload, plen);
204 sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
205 sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
206 parse_gpg_output(sigc);
207 status |= sigc->result != 'G' && sigc->result != 'U';
208
209 out:
210 strbuf_release(&gpg_status);
211 strbuf_release(&gpg_output);
212
213 return !!status;
214 }
215
216 void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
217 {
218 const char *output = flags & GPG_VERIFY_RAW ?
219 sigc->gpg_status : sigc->gpg_output;
220
221 if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
222 fputs(sigc->payload, stdout);
223
224 if (output)
225 fputs(output, stderr);
226 }
227
228 size_t parse_signature(const char *buf, size_t size)
229 {
230 size_t len = 0;
231 size_t match = size;
232 while (len < size) {
233 const char *eol;
234
235 if (get_format_by_sig(buf + len))
236 match = len;
237
238 eol = memchr(buf + len, '\n', size - len);
239 len += eol ? eol - (buf + len) + 1 : size - len;
240 }
241 return match;
242 }
243
244 void set_signing_key(const char *key)
245 {
246 free(configured_signing_key);
247 configured_signing_key = xstrdup(key);
248 }
249
250 int git_gpg_config(const char *var, const char *value, void *cb)
251 {
252 struct gpg_format *fmt = NULL;
253 char *fmtname = NULL;
254
255 if (!strcmp(var, "user.signingkey")) {
256 if (!value)
257 return config_error_nonbool(var);
258 set_signing_key(value);
259 return 0;
260 }
261
262 if (!strcmp(var, "gpg.format")) {
263 if (!value)
264 return config_error_nonbool(var);
265 fmt = get_format_by_name(value);
266 if (!fmt)
267 return error("unsupported value for %s: %s",
268 var, value);
269 use_format = fmt;
270 return 0;
271 }
272
273 if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
274 fmtname = "openpgp";
275
276 if (!strcmp(var, "gpg.x509.program"))
277 fmtname = "x509";
278
279 if (fmtname) {
280 fmt = get_format_by_name(fmtname);
281 return git_config_string(&fmt->program, var, value);
282 }
283
284 return 0;
285 }
286
287 const char *get_signing_key(void)
288 {
289 if (configured_signing_key)
290 return configured_signing_key;
291 return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
292 }
293
294 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
295 {
296 struct child_process gpg = CHILD_PROCESS_INIT;
297 int ret;
298 size_t i, j, bottom;
299 struct strbuf gpg_status = STRBUF_INIT;
300
301 argv_array_pushl(&gpg.args,
302 use_format->program,
303 "--status-fd=2",
304 "-bsau", signing_key,
305 NULL);
306
307 bottom = signature->len;
308
309 /*
310 * When the username signingkey is bad, program could be terminated
311 * because gpg exits without reading and then write gets SIGPIPE.
312 */
313 sigchain_push(SIGPIPE, SIG_IGN);
314 ret = pipe_command(&gpg, buffer->buf, buffer->len,
315 signature, 1024, &gpg_status, 0);
316 sigchain_pop(SIGPIPE);
317
318 ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
319 strbuf_release(&gpg_status);
320 if (ret)
321 return error(_("gpg failed to sign the data"));
322
323 /* Strip CR from the line endings, in case we are on Windows. */
324 for (i = j = bottom; i < signature->len; i++)
325 if (signature->buf[i] != '\r') {
326 if (i != j)
327 signature->buf[j] = signature->buf[i];
328 j++;
329 }
330 strbuf_setlen(signature, j);
331
332 return 0;
333 }
334
335 int verify_signed_buffer(const char *payload, size_t payload_size,
336 const char *signature, size_t signature_size,
337 struct strbuf *gpg_output, struct strbuf *gpg_status)
338 {
339 struct child_process gpg = CHILD_PROCESS_INIT;
340 struct gpg_format *fmt;
341 struct tempfile *temp;
342 int ret;
343 struct strbuf buf = STRBUF_INIT;
344
345 temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
346 if (!temp)
347 return error_errno(_("could not create temporary file"));
348 if (write_in_full(temp->fd, signature, signature_size) < 0 ||
349 close_tempfile_gently(temp) < 0) {
350 error_errno(_("failed writing detached signature to '%s'"),
351 temp->filename.buf);
352 delete_tempfile(&temp);
353 return -1;
354 }
355
356 fmt = get_format_by_sig(signature);
357 if (!fmt)
358 BUG("bad signature '%s'", signature);
359
360 argv_array_push(&gpg.args, fmt->program);
361 argv_array_pushv(&gpg.args, fmt->verify_args);
362 argv_array_pushl(&gpg.args,
363 "--status-fd=1",
364 "--verify", temp->filename.buf, "-",
365 NULL);
366
367 if (!gpg_status)
368 gpg_status = &buf;
369
370 sigchain_push(SIGPIPE, SIG_IGN);
371 ret = pipe_command(&gpg, payload, payload_size,
372 gpg_status, 0, gpg_output, 0);
373 sigchain_pop(SIGPIPE);
374
375 delete_tempfile(&temp);
376
377 ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
378 strbuf_release(&buf); /* no matter it was used or not */
379
380 return ret;
381 }