]>
Commit | Line | Data |
---|---|---|
1 | #include "git-compat-util.h" | |
2 | #include "commit.h" | |
3 | #include "config.h" | |
4 | #include "date.h" | |
5 | #include "gettext.h" | |
6 | #include "run-command.h" | |
7 | #include "strbuf.h" | |
8 | #include "dir.h" | |
9 | #include "ident.h" | |
10 | #include "gpg-interface.h" | |
11 | #include "path.h" | |
12 | #include "sigchain.h" | |
13 | #include "tempfile.h" | |
14 | #include "alias.h" | |
15 | ||
16 | static int git_gpg_config(const char *, const char *, | |
17 | const struct config_context *, void *); | |
18 | ||
19 | static void gpg_interface_lazy_init(void) | |
20 | { | |
21 | static int done; | |
22 | ||
23 | if (done) | |
24 | return; | |
25 | done = 1; | |
26 | git_config(git_gpg_config, NULL); | |
27 | } | |
28 | ||
29 | static char *configured_signing_key; | |
30 | static const char *ssh_default_key_command, *ssh_allowed_signers, *ssh_revocation_file; | |
31 | static enum signature_trust_level configured_min_trust_level = TRUST_UNDEFINED; | |
32 | ||
33 | struct gpg_format { | |
34 | const char *name; | |
35 | const char *program; | |
36 | const char **verify_args; | |
37 | const char **sigs; | |
38 | int (*verify_signed_buffer)(struct signature_check *sigc, | |
39 | struct gpg_format *fmt, | |
40 | const char *signature, | |
41 | size_t signature_size); | |
42 | int (*sign_buffer)(struct strbuf *buffer, struct strbuf *signature, | |
43 | const char *signing_key); | |
44 | const char *(*get_default_key)(void); | |
45 | const char *(*get_key_id)(void); | |
46 | }; | |
47 | ||
48 | static const char *openpgp_verify_args[] = { | |
49 | "--keyid-format=long", | |
50 | NULL | |
51 | }; | |
52 | static const char *openpgp_sigs[] = { | |
53 | "-----BEGIN PGP SIGNATURE-----", | |
54 | "-----BEGIN PGP MESSAGE-----", | |
55 | NULL | |
56 | }; | |
57 | ||
58 | static const char *x509_verify_args[] = { | |
59 | NULL | |
60 | }; | |
61 | static const char *x509_sigs[] = { | |
62 | "-----BEGIN SIGNED MESSAGE-----", | |
63 | NULL | |
64 | }; | |
65 | ||
66 | static const char *ssh_verify_args[] = { NULL }; | |
67 | static const char *ssh_sigs[] = { | |
68 | "-----BEGIN SSH SIGNATURE-----", | |
69 | NULL | |
70 | }; | |
71 | ||
72 | static int verify_gpg_signed_buffer(struct signature_check *sigc, | |
73 | struct gpg_format *fmt, | |
74 | const char *signature, | |
75 | size_t signature_size); | |
76 | static int verify_ssh_signed_buffer(struct signature_check *sigc, | |
77 | struct gpg_format *fmt, | |
78 | const char *signature, | |
79 | size_t signature_size); | |
80 | static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature, | |
81 | const char *signing_key); | |
82 | static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature, | |
83 | const char *signing_key); | |
84 | ||
85 | static const char *get_default_ssh_signing_key(void); | |
86 | ||
87 | static const char *get_ssh_key_id(void); | |
88 | ||
89 | static struct gpg_format gpg_format[] = { | |
90 | { | |
91 | .name = "openpgp", | |
92 | .program = "gpg", | |
93 | .verify_args = openpgp_verify_args, | |
94 | .sigs = openpgp_sigs, | |
95 | .verify_signed_buffer = verify_gpg_signed_buffer, | |
96 | .sign_buffer = sign_buffer_gpg, | |
97 | .get_default_key = NULL, | |
98 | .get_key_id = NULL, | |
99 | }, | |
100 | { | |
101 | .name = "x509", | |
102 | .program = "gpgsm", | |
103 | .verify_args = x509_verify_args, | |
104 | .sigs = x509_sigs, | |
105 | .verify_signed_buffer = verify_gpg_signed_buffer, | |
106 | .sign_buffer = sign_buffer_gpg, | |
107 | .get_default_key = NULL, | |
108 | .get_key_id = NULL, | |
109 | }, | |
110 | { | |
111 | .name = "ssh", | |
112 | .program = "ssh-keygen", | |
113 | .verify_args = ssh_verify_args, | |
114 | .sigs = ssh_sigs, | |
115 | .verify_signed_buffer = verify_ssh_signed_buffer, | |
116 | .sign_buffer = sign_buffer_ssh, | |
117 | .get_default_key = get_default_ssh_signing_key, | |
118 | .get_key_id = get_ssh_key_id, | |
119 | }, | |
120 | }; | |
121 | ||
122 | static struct gpg_format *use_format = &gpg_format[0]; | |
123 | ||
124 | static struct gpg_format *get_format_by_name(const char *str) | |
125 | { | |
126 | int i; | |
127 | ||
128 | for (i = 0; i < ARRAY_SIZE(gpg_format); i++) | |
129 | if (!strcmp(gpg_format[i].name, str)) | |
130 | return gpg_format + i; | |
131 | return NULL; | |
132 | } | |
133 | ||
134 | static struct gpg_format *get_format_by_sig(const char *sig) | |
135 | { | |
136 | int i, j; | |
137 | ||
138 | for (i = 0; i < ARRAY_SIZE(gpg_format); i++) | |
139 | for (j = 0; gpg_format[i].sigs[j]; j++) | |
140 | if (starts_with(sig, gpg_format[i].sigs[j])) | |
141 | return gpg_format + i; | |
142 | return NULL; | |
143 | } | |
144 | ||
145 | void signature_check_clear(struct signature_check *sigc) | |
146 | { | |
147 | FREE_AND_NULL(sigc->payload); | |
148 | FREE_AND_NULL(sigc->output); | |
149 | FREE_AND_NULL(sigc->gpg_status); | |
150 | FREE_AND_NULL(sigc->signer); | |
151 | FREE_AND_NULL(sigc->key); | |
152 | FREE_AND_NULL(sigc->fingerprint); | |
153 | FREE_AND_NULL(sigc->primary_key_fingerprint); | |
154 | } | |
155 | ||
156 | /* An exclusive status -- only one of them can appear in output */ | |
157 | #define GPG_STATUS_EXCLUSIVE (1<<0) | |
158 | /* The status includes key identifier */ | |
159 | #define GPG_STATUS_KEYID (1<<1) | |
160 | /* The status includes user identifier */ | |
161 | #define GPG_STATUS_UID (1<<2) | |
162 | /* The status includes key fingerprints */ | |
163 | #define GPG_STATUS_FINGERPRINT (1<<3) | |
164 | /* The status includes trust level */ | |
165 | #define GPG_STATUS_TRUST_LEVEL (1<<4) | |
166 | ||
167 | /* Short-hand for standard exclusive *SIG status with keyid & UID */ | |
168 | #define GPG_STATUS_STDSIG (GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID|GPG_STATUS_UID) | |
169 | ||
170 | static struct { | |
171 | char result; | |
172 | const char *check; | |
173 | unsigned int flags; | |
174 | } sigcheck_gpg_status[] = { | |
175 | { 'G', "GOODSIG ", GPG_STATUS_STDSIG }, | |
176 | { 'B', "BADSIG ", GPG_STATUS_STDSIG }, | |
177 | { 'E', "ERRSIG ", GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID }, | |
178 | { 'X', "EXPSIG ", GPG_STATUS_STDSIG }, | |
179 | { 'Y', "EXPKEYSIG ", GPG_STATUS_STDSIG }, | |
180 | { 'R', "REVKEYSIG ", GPG_STATUS_STDSIG }, | |
181 | { 0, "VALIDSIG ", GPG_STATUS_FINGERPRINT }, | |
182 | { 0, "TRUST_", GPG_STATUS_TRUST_LEVEL }, | |
183 | }; | |
184 | ||
185 | /* Keep the order same as enum signature_trust_level */ | |
186 | static struct sigcheck_gpg_trust_level { | |
187 | const char *key; | |
188 | const char *display_key; | |
189 | enum signature_trust_level value; | |
190 | } sigcheck_gpg_trust_level[] = { | |
191 | { "UNDEFINED", "undefined", TRUST_UNDEFINED }, | |
192 | { "NEVER", "never", TRUST_NEVER }, | |
193 | { "MARGINAL", "marginal", TRUST_MARGINAL }, | |
194 | { "FULLY", "fully", TRUST_FULLY }, | |
195 | { "ULTIMATE", "ultimate", TRUST_ULTIMATE }, | |
196 | }; | |
197 | ||
198 | static void replace_cstring(char **field, const char *line, const char *next) | |
199 | { | |
200 | free(*field); | |
201 | ||
202 | if (line && next) | |
203 | *field = xmemdupz(line, next - line); | |
204 | else | |
205 | *field = NULL; | |
206 | } | |
207 | ||
208 | static int parse_gpg_trust_level(const char *level, | |
209 | enum signature_trust_level *res) | |
210 | { | |
211 | size_t i; | |
212 | ||
213 | for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_trust_level); i++) { | |
214 | if (!strcmp(sigcheck_gpg_trust_level[i].key, level)) { | |
215 | *res = sigcheck_gpg_trust_level[i].value; | |
216 | return 0; | |
217 | } | |
218 | } | |
219 | return 1; | |
220 | } | |
221 | ||
222 | static void parse_gpg_output(struct signature_check *sigc) | |
223 | { | |
224 | const char *buf = sigc->gpg_status; | |
225 | const char *line, *next; | |
226 | int i, j; | |
227 | int seen_exclusive_status = 0; | |
228 | ||
229 | /* Iterate over all lines */ | |
230 | for (line = buf; *line; line = strchrnul(line+1, '\n')) { | |
231 | while (*line == '\n') | |
232 | line++; | |
233 | if (!*line) | |
234 | break; | |
235 | ||
236 | /* Skip lines that don't start with GNUPG status */ | |
237 | if (!skip_prefix(line, "[GNUPG:] ", &line)) | |
238 | continue; | |
239 | ||
240 | /* Iterate over all search strings */ | |
241 | for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) { | |
242 | if (skip_prefix(line, sigcheck_gpg_status[i].check, &line)) { | |
243 | /* | |
244 | * GOODSIG, BADSIG etc. can occur only once for | |
245 | * each signature. Therefore, if we had more | |
246 | * than one then we're dealing with multiple | |
247 | * signatures. We don't support them | |
248 | * currently, and they're rather hard to | |
249 | * create, so something is likely fishy and we | |
250 | * should reject them altogether. | |
251 | */ | |
252 | if (sigcheck_gpg_status[i].flags & GPG_STATUS_EXCLUSIVE) { | |
253 | if (seen_exclusive_status++) | |
254 | goto error; | |
255 | } | |
256 | ||
257 | if (sigcheck_gpg_status[i].result) | |
258 | sigc->result = sigcheck_gpg_status[i].result; | |
259 | /* Do we have key information? */ | |
260 | if (sigcheck_gpg_status[i].flags & GPG_STATUS_KEYID) { | |
261 | next = strchrnul(line, ' '); | |
262 | replace_cstring(&sigc->key, line, next); | |
263 | /* Do we have signer information? */ | |
264 | if (*next && (sigcheck_gpg_status[i].flags & GPG_STATUS_UID)) { | |
265 | line = next + 1; | |
266 | next = strchrnul(line, '\n'); | |
267 | replace_cstring(&sigc->signer, line, next); | |
268 | } | |
269 | } | |
270 | ||
271 | /* Do we have trust level? */ | |
272 | if (sigcheck_gpg_status[i].flags & GPG_STATUS_TRUST_LEVEL) { | |
273 | /* | |
274 | * GPG v1 and v2 differs in how the | |
275 | * TRUST_ lines are written. Some | |
276 | * trust lines contain no additional | |
277 | * space-separated information for v1. | |
278 | */ | |
279 | size_t trust_size = strcspn(line, " \n"); | |
280 | char *trust = xmemdupz(line, trust_size); | |
281 | ||
282 | if (parse_gpg_trust_level(trust, &sigc->trust_level)) { | |
283 | free(trust); | |
284 | goto error; | |
285 | } | |
286 | free(trust); | |
287 | } | |
288 | ||
289 | /* Do we have fingerprint? */ | |
290 | if (sigcheck_gpg_status[i].flags & GPG_STATUS_FINGERPRINT) { | |
291 | const char *limit; | |
292 | char **field; | |
293 | ||
294 | next = strchrnul(line, ' '); | |
295 | replace_cstring(&sigc->fingerprint, line, next); | |
296 | ||
297 | /* | |
298 | * Skip interim fields. The search is | |
299 | * limited to the same line since only | |
300 | * OpenPGP signatures has a field with | |
301 | * the primary fingerprint. | |
302 | */ | |
303 | limit = strchrnul(line, '\n'); | |
304 | for (j = 9; j > 0; j--) { | |
305 | if (!*next || limit <= next) | |
306 | break; | |
307 | line = next + 1; | |
308 | next = strchrnul(line, ' '); | |
309 | } | |
310 | ||
311 | field = &sigc->primary_key_fingerprint; | |
312 | if (!j) { | |
313 | next = strchrnul(line, '\n'); | |
314 | replace_cstring(field, line, next); | |
315 | } else { | |
316 | replace_cstring(field, NULL, NULL); | |
317 | } | |
318 | } | |
319 | ||
320 | break; | |
321 | } | |
322 | } | |
323 | } | |
324 | return; | |
325 | ||
326 | error: | |
327 | sigc->result = 'E'; | |
328 | /* Clear partial data to avoid confusion */ | |
329 | FREE_AND_NULL(sigc->primary_key_fingerprint); | |
330 | FREE_AND_NULL(sigc->fingerprint); | |
331 | FREE_AND_NULL(sigc->signer); | |
332 | FREE_AND_NULL(sigc->key); | |
333 | } | |
334 | ||
335 | static int verify_gpg_signed_buffer(struct signature_check *sigc, | |
336 | struct gpg_format *fmt, | |
337 | const char *signature, | |
338 | size_t signature_size) | |
339 | { | |
340 | struct child_process gpg = CHILD_PROCESS_INIT; | |
341 | struct tempfile *temp; | |
342 | int ret; | |
343 | struct strbuf gpg_stdout = STRBUF_INIT; | |
344 | struct strbuf gpg_stderr = STRBUF_INIT; | |
345 | ||
346 | temp = mks_tempfile_t(".git_vtag_tmpXXXXXX"); | |
347 | if (!temp) | |
348 | return error_errno(_("could not create temporary file")); | |
349 | if (write_in_full(temp->fd, signature, signature_size) < 0 || | |
350 | close_tempfile_gently(temp) < 0) { | |
351 | error_errno(_("failed writing detached signature to '%s'"), | |
352 | temp->filename.buf); | |
353 | delete_tempfile(&temp); | |
354 | return -1; | |
355 | } | |
356 | ||
357 | strvec_push(&gpg.args, fmt->program); | |
358 | strvec_pushv(&gpg.args, fmt->verify_args); | |
359 | strvec_pushl(&gpg.args, | |
360 | "--status-fd=1", | |
361 | "--verify", temp->filename.buf, "-", | |
362 | NULL); | |
363 | ||
364 | sigchain_push(SIGPIPE, SIG_IGN); | |
365 | ret = pipe_command(&gpg, sigc->payload, sigc->payload_len, &gpg_stdout, 0, | |
366 | &gpg_stderr, 0); | |
367 | sigchain_pop(SIGPIPE); | |
368 | ||
369 | delete_tempfile(&temp); | |
370 | ||
371 | ret |= !strstr(gpg_stdout.buf, "\n[GNUPG:] GOODSIG "); | |
372 | sigc->output = strbuf_detach(&gpg_stderr, NULL); | |
373 | sigc->gpg_status = strbuf_detach(&gpg_stdout, NULL); | |
374 | ||
375 | parse_gpg_output(sigc); | |
376 | ||
377 | strbuf_release(&gpg_stdout); | |
378 | strbuf_release(&gpg_stderr); | |
379 | ||
380 | return ret; | |
381 | } | |
382 | ||
383 | static void parse_ssh_output(struct signature_check *sigc) | |
384 | { | |
385 | const char *line, *principal, *search; | |
386 | char *to_free; | |
387 | char *key = NULL; | |
388 | ||
389 | /* | |
390 | * ssh-keygen output should be: | |
391 | * Good "git" signature for PRINCIPAL with RSA key SHA256:FINGERPRINT | |
392 | * | |
393 | * or for valid but unknown keys: | |
394 | * Good "git" signature with RSA key SHA256:FINGERPRINT | |
395 | * | |
396 | * Note that "PRINCIPAL" can contain whitespace, "RSA" and | |
397 | * "SHA256" part could be a different token that names of | |
398 | * the algorithms used, and "FINGERPRINT" is a hexadecimal | |
399 | * string. By finding the last occurence of " with ", we can | |
400 | * reliably parse out the PRINCIPAL. | |
401 | */ | |
402 | sigc->result = 'B'; | |
403 | sigc->trust_level = TRUST_NEVER; | |
404 | ||
405 | line = to_free = xmemdupz(sigc->output, strcspn(sigc->output, "\n")); | |
406 | ||
407 | if (skip_prefix(line, "Good \"git\" signature for ", &line)) { | |
408 | /* Search for the last "with" to get the full principal */ | |
409 | principal = line; | |
410 | do { | |
411 | search = strstr(line, " with "); | |
412 | if (search) | |
413 | line = search + 1; | |
414 | } while (search != NULL); | |
415 | if (line == principal) | |
416 | goto cleanup; | |
417 | ||
418 | /* Valid signature and known principal */ | |
419 | sigc->result = 'G'; | |
420 | sigc->trust_level = TRUST_FULLY; | |
421 | sigc->signer = xmemdupz(principal, line - principal - 1); | |
422 | } else if (skip_prefix(line, "Good \"git\" signature with ", &line)) { | |
423 | /* Valid signature, but key unknown */ | |
424 | sigc->result = 'G'; | |
425 | sigc->trust_level = TRUST_UNDEFINED; | |
426 | } else { | |
427 | goto cleanup; | |
428 | } | |
429 | ||
430 | key = strstr(line, "key "); | |
431 | if (key) { | |
432 | sigc->fingerprint = xstrdup(strstr(line, "key ") + 4); | |
433 | sigc->key = xstrdup(sigc->fingerprint); | |
434 | } else { | |
435 | /* | |
436 | * Output did not match what we expected | |
437 | * Treat the signature as bad | |
438 | */ | |
439 | sigc->result = 'B'; | |
440 | } | |
441 | ||
442 | cleanup: | |
443 | free(to_free); | |
444 | } | |
445 | ||
446 | static int verify_ssh_signed_buffer(struct signature_check *sigc, | |
447 | struct gpg_format *fmt, | |
448 | const char *signature, | |
449 | size_t signature_size) | |
450 | { | |
451 | struct child_process ssh_keygen = CHILD_PROCESS_INIT; | |
452 | struct tempfile *buffer_file; | |
453 | int ret = -1; | |
454 | const char *line; | |
455 | char *principal; | |
456 | struct strbuf ssh_principals_out = STRBUF_INIT; | |
457 | struct strbuf ssh_principals_err = STRBUF_INIT; | |
458 | struct strbuf ssh_keygen_out = STRBUF_INIT; | |
459 | struct strbuf ssh_keygen_err = STRBUF_INIT; | |
460 | struct strbuf verify_time = STRBUF_INIT; | |
461 | const struct date_mode verify_date_mode = { | |
462 | .type = DATE_STRFTIME, | |
463 | .strftime_fmt = "%Y%m%d%H%M%S", | |
464 | /* SSH signing key validity has no timezone information - Use the local timezone */ | |
465 | .local = 1, | |
466 | }; | |
467 | ||
468 | if (!ssh_allowed_signers) { | |
469 | error(_("gpg.ssh.allowedSignersFile needs to be configured and exist for ssh signature verification")); | |
470 | return -1; | |
471 | } | |
472 | ||
473 | buffer_file = mks_tempfile_t(".git_vtag_tmpXXXXXX"); | |
474 | if (!buffer_file) | |
475 | return error_errno(_("could not create temporary file")); | |
476 | if (write_in_full(buffer_file->fd, signature, signature_size) < 0 || | |
477 | close_tempfile_gently(buffer_file) < 0) { | |
478 | error_errno(_("failed writing detached signature to '%s'"), | |
479 | buffer_file->filename.buf); | |
480 | delete_tempfile(&buffer_file); | |
481 | return -1; | |
482 | } | |
483 | ||
484 | if (sigc->payload_timestamp) | |
485 | strbuf_addf(&verify_time, "-Overify-time=%s", | |
486 | show_date(sigc->payload_timestamp, 0, verify_date_mode)); | |
487 | ||
488 | /* Find the principal from the signers */ | |
489 | strvec_pushl(&ssh_keygen.args, fmt->program, | |
490 | "-Y", "find-principals", | |
491 | "-f", ssh_allowed_signers, | |
492 | "-s", buffer_file->filename.buf, | |
493 | verify_time.buf, | |
494 | NULL); | |
495 | ret = pipe_command(&ssh_keygen, NULL, 0, &ssh_principals_out, 0, | |
496 | &ssh_principals_err, 0); | |
497 | if (ret && strstr(ssh_principals_err.buf, "usage:")) { | |
498 | error(_("ssh-keygen -Y find-principals/verify is needed for ssh signature verification (available in openssh version 8.2p1+)")); | |
499 | goto out; | |
500 | } | |
501 | if (ret || !ssh_principals_out.len) { | |
502 | /* | |
503 | * We did not find a matching principal in the allowedSigners | |
504 | * Check without validation | |
505 | */ | |
506 | child_process_init(&ssh_keygen); | |
507 | strvec_pushl(&ssh_keygen.args, fmt->program, | |
508 | "-Y", "check-novalidate", | |
509 | "-n", "git", | |
510 | "-s", buffer_file->filename.buf, | |
511 | verify_time.buf, | |
512 | NULL); | |
513 | pipe_command(&ssh_keygen, sigc->payload, sigc->payload_len, | |
514 | &ssh_keygen_out, 0, &ssh_keygen_err, 0); | |
515 | ||
516 | /* | |
517 | * Fail on unknown keys | |
518 | * we still call check-novalidate to display the signature info | |
519 | */ | |
520 | ret = -1; | |
521 | } else { | |
522 | /* Check every principal we found (one per line) */ | |
523 | const char *next; | |
524 | for (line = ssh_principals_out.buf; | |
525 | *line; | |
526 | line = next) { | |
527 | const char *end_of_text; | |
528 | ||
529 | next = end_of_text = strchrnul(line, '\n'); | |
530 | ||
531 | /* Did we find a LF, and did we have CR before it? */ | |
532 | if (*end_of_text && | |
533 | line < end_of_text && | |
534 | end_of_text[-1] == '\r') | |
535 | end_of_text--; | |
536 | ||
537 | /* Unless we hit NUL, skip over the LF we found */ | |
538 | if (*next) | |
539 | next++; | |
540 | ||
541 | /* Not all lines are data. Skip empty ones */ | |
542 | if (line == end_of_text) | |
543 | continue; | |
544 | ||
545 | /* We now know we have an non-empty line. Process it */ | |
546 | principal = xmemdupz(line, end_of_text - line); | |
547 | ||
548 | child_process_init(&ssh_keygen); | |
549 | strbuf_release(&ssh_keygen_out); | |
550 | strbuf_release(&ssh_keygen_err); | |
551 | strvec_push(&ssh_keygen.args, fmt->program); | |
552 | /* | |
553 | * We found principals | |
554 | * Try with each until we find a match | |
555 | */ | |
556 | strvec_pushl(&ssh_keygen.args, "-Y", "verify", | |
557 | "-n", "git", | |
558 | "-f", ssh_allowed_signers, | |
559 | "-I", principal, | |
560 | "-s", buffer_file->filename.buf, | |
561 | verify_time.buf, | |
562 | NULL); | |
563 | ||
564 | if (ssh_revocation_file) { | |
565 | if (file_exists(ssh_revocation_file)) { | |
566 | strvec_pushl(&ssh_keygen.args, "-r", | |
567 | ssh_revocation_file, NULL); | |
568 | } else { | |
569 | warning(_("ssh signing revocation file configured but not found: %s"), | |
570 | ssh_revocation_file); | |
571 | } | |
572 | } | |
573 | ||
574 | sigchain_push(SIGPIPE, SIG_IGN); | |
575 | ret = pipe_command(&ssh_keygen, sigc->payload, sigc->payload_len, | |
576 | &ssh_keygen_out, 0, &ssh_keygen_err, 0); | |
577 | sigchain_pop(SIGPIPE); | |
578 | ||
579 | FREE_AND_NULL(principal); | |
580 | ||
581 | if (!ret) | |
582 | ret = !starts_with(ssh_keygen_out.buf, "Good"); | |
583 | ||
584 | if (!ret) | |
585 | break; | |
586 | } | |
587 | } | |
588 | ||
589 | strbuf_stripspace(&ssh_keygen_out, NULL); | |
590 | strbuf_stripspace(&ssh_keygen_err, NULL); | |
591 | /* Add stderr outputs to show the user actual ssh-keygen errors */ | |
592 | strbuf_add(&ssh_keygen_out, ssh_principals_err.buf, ssh_principals_err.len); | |
593 | strbuf_add(&ssh_keygen_out, ssh_keygen_err.buf, ssh_keygen_err.len); | |
594 | sigc->output = strbuf_detach(&ssh_keygen_out, NULL); | |
595 | sigc->gpg_status = xstrdup(sigc->output); | |
596 | ||
597 | parse_ssh_output(sigc); | |
598 | ||
599 | out: | |
600 | if (buffer_file) | |
601 | delete_tempfile(&buffer_file); | |
602 | strbuf_release(&ssh_principals_out); | |
603 | strbuf_release(&ssh_principals_err); | |
604 | strbuf_release(&ssh_keygen_out); | |
605 | strbuf_release(&ssh_keygen_err); | |
606 | strbuf_release(&verify_time); | |
607 | ||
608 | return ret; | |
609 | } | |
610 | ||
611 | static int parse_payload_metadata(struct signature_check *sigc) | |
612 | { | |
613 | const char *ident_line = NULL; | |
614 | size_t ident_len; | |
615 | struct ident_split ident; | |
616 | const char *signer_header; | |
617 | ||
618 | switch (sigc->payload_type) { | |
619 | case SIGNATURE_PAYLOAD_COMMIT: | |
620 | signer_header = "committer"; | |
621 | break; | |
622 | case SIGNATURE_PAYLOAD_TAG: | |
623 | signer_header = "tagger"; | |
624 | break; | |
625 | case SIGNATURE_PAYLOAD_UNDEFINED: | |
626 | case SIGNATURE_PAYLOAD_PUSH_CERT: | |
627 | /* Ignore payloads we don't want to parse */ | |
628 | return 0; | |
629 | default: | |
630 | BUG("invalid value for sigc->payload_type"); | |
631 | } | |
632 | ||
633 | ident_line = find_commit_header(sigc->payload, signer_header, &ident_len); | |
634 | if (!ident_line || !ident_len) | |
635 | return 1; | |
636 | ||
637 | if (split_ident_line(&ident, ident_line, ident_len)) | |
638 | return 1; | |
639 | ||
640 | if (!sigc->payload_timestamp && ident.date_begin && ident.date_end) | |
641 | sigc->payload_timestamp = parse_timestamp(ident.date_begin, NULL, 10); | |
642 | ||
643 | return 0; | |
644 | } | |
645 | ||
646 | int check_signature(struct signature_check *sigc, | |
647 | const char *signature, size_t slen) | |
648 | { | |
649 | struct gpg_format *fmt; | |
650 | int status; | |
651 | ||
652 | gpg_interface_lazy_init(); | |
653 | ||
654 | sigc->result = 'N'; | |
655 | sigc->trust_level = TRUST_UNDEFINED; | |
656 | ||
657 | fmt = get_format_by_sig(signature); | |
658 | if (!fmt) | |
659 | die(_("bad/incompatible signature '%s'"), signature); | |
660 | ||
661 | if (parse_payload_metadata(sigc)) | |
662 | return 1; | |
663 | ||
664 | status = fmt->verify_signed_buffer(sigc, fmt, signature, slen); | |
665 | ||
666 | if (status && !sigc->output) | |
667 | return !!status; | |
668 | ||
669 | status |= sigc->result != 'G'; | |
670 | status |= sigc->trust_level < configured_min_trust_level; | |
671 | ||
672 | return !!status; | |
673 | } | |
674 | ||
675 | void print_signature_buffer(const struct signature_check *sigc, unsigned flags) | |
676 | { | |
677 | const char *output = flags & GPG_VERIFY_RAW ? sigc->gpg_status : | |
678 | sigc->output; | |
679 | ||
680 | if (flags & GPG_VERIFY_VERBOSE && sigc->payload) | |
681 | fwrite(sigc->payload, 1, sigc->payload_len, stdout); | |
682 | ||
683 | if (output) | |
684 | fputs(output, stderr); | |
685 | } | |
686 | ||
687 | size_t parse_signed_buffer(const char *buf, size_t size) | |
688 | { | |
689 | size_t len = 0; | |
690 | size_t match = size; | |
691 | while (len < size) { | |
692 | const char *eol; | |
693 | ||
694 | if (get_format_by_sig(buf + len)) | |
695 | match = len; | |
696 | ||
697 | eol = memchr(buf + len, '\n', size - len); | |
698 | len += eol ? eol - (buf + len) + 1 : size - len; | |
699 | } | |
700 | return match; | |
701 | } | |
702 | ||
703 | int parse_signature(const char *buf, size_t size, struct strbuf *payload, struct strbuf *signature) | |
704 | { | |
705 | size_t match = parse_signed_buffer(buf, size); | |
706 | if (match != size) { | |
707 | strbuf_add(payload, buf, match); | |
708 | remove_signature(payload); | |
709 | strbuf_add(signature, buf + match, size - match); | |
710 | return 1; | |
711 | } | |
712 | return 0; | |
713 | } | |
714 | ||
715 | void set_signing_key(const char *key) | |
716 | { | |
717 | gpg_interface_lazy_init(); | |
718 | ||
719 | free(configured_signing_key); | |
720 | configured_signing_key = xstrdup(key); | |
721 | } | |
722 | ||
723 | static int git_gpg_config(const char *var, const char *value, | |
724 | const struct config_context *ctx UNUSED, | |
725 | void *cb UNUSED) | |
726 | { | |
727 | struct gpg_format *fmt = NULL; | |
728 | char *fmtname = NULL; | |
729 | char *trust; | |
730 | int ret; | |
731 | ||
732 | if (!strcmp(var, "user.signingkey")) { | |
733 | if (!value) | |
734 | return config_error_nonbool(var); | |
735 | set_signing_key(value); | |
736 | return 0; | |
737 | } | |
738 | ||
739 | if (!strcmp(var, "gpg.format")) { | |
740 | if (!value) | |
741 | return config_error_nonbool(var); | |
742 | fmt = get_format_by_name(value); | |
743 | if (!fmt) | |
744 | return error(_("invalid value for '%s': '%s'"), | |
745 | var, value); | |
746 | use_format = fmt; | |
747 | return 0; | |
748 | } | |
749 | ||
750 | if (!strcmp(var, "gpg.mintrustlevel")) { | |
751 | if (!value) | |
752 | return config_error_nonbool(var); | |
753 | ||
754 | trust = xstrdup_toupper(value); | |
755 | ret = parse_gpg_trust_level(trust, &configured_min_trust_level); | |
756 | free(trust); | |
757 | ||
758 | if (ret) | |
759 | return error(_("invalid value for '%s': '%s'"), | |
760 | var, value); | |
761 | return 0; | |
762 | } | |
763 | ||
764 | if (!strcmp(var, "gpg.ssh.defaultkeycommand")) | |
765 | return git_config_string(&ssh_default_key_command, var, value); | |
766 | ||
767 | if (!strcmp(var, "gpg.ssh.allowedsignersfile")) | |
768 | return git_config_pathname(&ssh_allowed_signers, var, value); | |
769 | ||
770 | if (!strcmp(var, "gpg.ssh.revocationfile")) | |
771 | return git_config_pathname(&ssh_revocation_file, var, value); | |
772 | ||
773 | if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program")) | |
774 | fmtname = "openpgp"; | |
775 | ||
776 | if (!strcmp(var, "gpg.x509.program")) | |
777 | fmtname = "x509"; | |
778 | ||
779 | if (!strcmp(var, "gpg.ssh.program")) | |
780 | fmtname = "ssh"; | |
781 | ||
782 | if (fmtname) { | |
783 | fmt = get_format_by_name(fmtname); | |
784 | return git_config_string(&fmt->program, var, value); | |
785 | } | |
786 | ||
787 | return 0; | |
788 | } | |
789 | ||
790 | /* | |
791 | * Returns 1 if `string` contains a literal ssh key, 0 otherwise | |
792 | * `key` will be set to the start of the actual key if a prefix is present. | |
793 | */ | |
794 | static int is_literal_ssh_key(const char *string, const char **key) | |
795 | { | |
796 | if (skip_prefix(string, "key::", key)) | |
797 | return 1; | |
798 | if (starts_with(string, "ssh-")) { | |
799 | *key = string; | |
800 | return 1; | |
801 | } | |
802 | return 0; | |
803 | } | |
804 | ||
805 | static char *get_ssh_key_fingerprint(const char *signing_key) | |
806 | { | |
807 | struct child_process ssh_keygen = CHILD_PROCESS_INIT; | |
808 | int ret = -1; | |
809 | struct strbuf fingerprint_stdout = STRBUF_INIT; | |
810 | struct strbuf **fingerprint; | |
811 | char *fingerprint_ret; | |
812 | const char *literal_key = NULL; | |
813 | ||
814 | /* | |
815 | * With SSH Signing this can contain a filename or a public key | |
816 | * For textual representation we usually want a fingerprint | |
817 | */ | |
818 | if (is_literal_ssh_key(signing_key, &literal_key)) { | |
819 | strvec_pushl(&ssh_keygen.args, "ssh-keygen", "-lf", "-", NULL); | |
820 | ret = pipe_command(&ssh_keygen, literal_key, | |
821 | strlen(literal_key), &fingerprint_stdout, 0, | |
822 | NULL, 0); | |
823 | } else { | |
824 | strvec_pushl(&ssh_keygen.args, "ssh-keygen", "-lf", | |
825 | configured_signing_key, NULL); | |
826 | ret = pipe_command(&ssh_keygen, NULL, 0, &fingerprint_stdout, 0, | |
827 | NULL, 0); | |
828 | } | |
829 | ||
830 | if (!!ret) | |
831 | die_errno(_("failed to get the ssh fingerprint for key '%s'"), | |
832 | signing_key); | |
833 | ||
834 | fingerprint = strbuf_split_max(&fingerprint_stdout, ' ', 3); | |
835 | if (!fingerprint[1]) | |
836 | die_errno(_("failed to get the ssh fingerprint for key '%s'"), | |
837 | signing_key); | |
838 | ||
839 | fingerprint_ret = strbuf_detach(fingerprint[1], NULL); | |
840 | strbuf_list_free(fingerprint); | |
841 | strbuf_release(&fingerprint_stdout); | |
842 | return fingerprint_ret; | |
843 | } | |
844 | ||
845 | /* Returns the first public key from an ssh-agent to use for signing */ | |
846 | static const char *get_default_ssh_signing_key(void) | |
847 | { | |
848 | struct child_process ssh_default_key = CHILD_PROCESS_INIT; | |
849 | int ret = -1; | |
850 | struct strbuf key_stdout = STRBUF_INIT, key_stderr = STRBUF_INIT; | |
851 | struct strbuf **keys; | |
852 | char *key_command = NULL; | |
853 | const char **argv; | |
854 | int n; | |
855 | char *default_key = NULL; | |
856 | const char *literal_key = NULL; | |
857 | ||
858 | if (!ssh_default_key_command) | |
859 | die(_("either user.signingkey or gpg.ssh.defaultKeyCommand needs to be configured")); | |
860 | ||
861 | key_command = xstrdup(ssh_default_key_command); | |
862 | n = split_cmdline(key_command, &argv); | |
863 | ||
864 | if (n < 0) | |
865 | die("malformed build-time gpg.ssh.defaultKeyCommand: %s", | |
866 | split_cmdline_strerror(n)); | |
867 | ||
868 | strvec_pushv(&ssh_default_key.args, argv); | |
869 | ret = pipe_command(&ssh_default_key, NULL, 0, &key_stdout, 0, | |
870 | &key_stderr, 0); | |
871 | ||
872 | if (!ret) { | |
873 | keys = strbuf_split_max(&key_stdout, '\n', 2); | |
874 | if (keys[0] && is_literal_ssh_key(keys[0]->buf, &literal_key)) { | |
875 | /* | |
876 | * We only use `is_literal_ssh_key` here to check validity | |
877 | * The prefix will be stripped when the key is used. | |
878 | */ | |
879 | default_key = strbuf_detach(keys[0], NULL); | |
880 | } else { | |
881 | warning(_("gpg.ssh.defaultKeyCommand succeeded but returned no keys: %s %s"), | |
882 | key_stderr.buf, key_stdout.buf); | |
883 | } | |
884 | ||
885 | strbuf_list_free(keys); | |
886 | } else { | |
887 | warning(_("gpg.ssh.defaultKeyCommand failed: %s %s"), | |
888 | key_stderr.buf, key_stdout.buf); | |
889 | } | |
890 | ||
891 | free(key_command); | |
892 | free(argv); | |
893 | strbuf_release(&key_stdout); | |
894 | ||
895 | return default_key; | |
896 | } | |
897 | ||
898 | static const char *get_ssh_key_id(void) { | |
899 | return get_ssh_key_fingerprint(get_signing_key()); | |
900 | } | |
901 | ||
902 | /* Returns a textual but unique representation of the signing key */ | |
903 | const char *get_signing_key_id(void) | |
904 | { | |
905 | gpg_interface_lazy_init(); | |
906 | ||
907 | if (use_format->get_key_id) { | |
908 | return use_format->get_key_id(); | |
909 | } | |
910 | ||
911 | /* GPG/GPGSM only store a key id on this variable */ | |
912 | return get_signing_key(); | |
913 | } | |
914 | ||
915 | const char *get_signing_key(void) | |
916 | { | |
917 | gpg_interface_lazy_init(); | |
918 | ||
919 | if (configured_signing_key) | |
920 | return configured_signing_key; | |
921 | if (use_format->get_default_key) { | |
922 | return use_format->get_default_key(); | |
923 | } | |
924 | ||
925 | return git_committer_info(IDENT_STRICT | IDENT_NO_DATE); | |
926 | } | |
927 | ||
928 | const char *gpg_trust_level_to_str(enum signature_trust_level level) | |
929 | { | |
930 | struct sigcheck_gpg_trust_level *trust; | |
931 | ||
932 | if (level < 0 || level >= ARRAY_SIZE(sigcheck_gpg_trust_level)) | |
933 | BUG("invalid trust level requested %d", level); | |
934 | ||
935 | trust = &sigcheck_gpg_trust_level[level]; | |
936 | if (trust->value != level) | |
937 | BUG("sigcheck_gpg_trust_level[] unsorted"); | |
938 | ||
939 | return sigcheck_gpg_trust_level[level].display_key; | |
940 | } | |
941 | ||
942 | int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key) | |
943 | { | |
944 | gpg_interface_lazy_init(); | |
945 | ||
946 | return use_format->sign_buffer(buffer, signature, signing_key); | |
947 | } | |
948 | ||
949 | /* | |
950 | * Strip CR from the line endings, in case we are on Windows. | |
951 | * NEEDSWORK: make it trim only CRs before LFs and rename | |
952 | */ | |
953 | static void remove_cr_after(struct strbuf *buffer, size_t offset) | |
954 | { | |
955 | size_t i, j; | |
956 | ||
957 | for (i = j = offset; i < buffer->len; i++) { | |
958 | if (buffer->buf[i] != '\r') { | |
959 | if (i != j) | |
960 | buffer->buf[j] = buffer->buf[i]; | |
961 | j++; | |
962 | } | |
963 | } | |
964 | strbuf_setlen(buffer, j); | |
965 | } | |
966 | ||
967 | static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature, | |
968 | const char *signing_key) | |
969 | { | |
970 | struct child_process gpg = CHILD_PROCESS_INIT; | |
971 | int ret; | |
972 | size_t bottom; | |
973 | const char *cp; | |
974 | struct strbuf gpg_status = STRBUF_INIT; | |
975 | ||
976 | strvec_pushl(&gpg.args, | |
977 | use_format->program, | |
978 | "--status-fd=2", | |
979 | "-bsau", signing_key, | |
980 | NULL); | |
981 | ||
982 | bottom = signature->len; | |
983 | ||
984 | /* | |
985 | * When the username signingkey is bad, program could be terminated | |
986 | * because gpg exits without reading and then write gets SIGPIPE. | |
987 | */ | |
988 | sigchain_push(SIGPIPE, SIG_IGN); | |
989 | ret = pipe_command(&gpg, buffer->buf, buffer->len, | |
990 | signature, 1024, &gpg_status, 0); | |
991 | sigchain_pop(SIGPIPE); | |
992 | ||
993 | for (cp = gpg_status.buf; | |
994 | cp && (cp = strstr(cp, "[GNUPG:] SIG_CREATED ")); | |
995 | cp++) { | |
996 | if (cp == gpg_status.buf || cp[-1] == '\n') | |
997 | break; /* found */ | |
998 | } | |
999 | ret |= !cp; | |
1000 | if (ret) { | |
1001 | error(_("gpg failed to sign the data:\n%s"), | |
1002 | gpg_status.len ? gpg_status.buf : "(no gpg output)"); | |
1003 | strbuf_release(&gpg_status); | |
1004 | return -1; | |
1005 | } | |
1006 | strbuf_release(&gpg_status); | |
1007 | ||
1008 | /* Strip CR from the line endings, in case we are on Windows. */ | |
1009 | remove_cr_after(signature, bottom); | |
1010 | ||
1011 | return 0; | |
1012 | } | |
1013 | ||
1014 | static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature, | |
1015 | const char *signing_key) | |
1016 | { | |
1017 | struct child_process signer = CHILD_PROCESS_INIT; | |
1018 | int ret = -1; | |
1019 | size_t bottom, keylen; | |
1020 | struct strbuf signer_stderr = STRBUF_INIT; | |
1021 | struct tempfile *key_file = NULL, *buffer_file = NULL; | |
1022 | char *ssh_signing_key_file = NULL; | |
1023 | struct strbuf ssh_signature_filename = STRBUF_INIT; | |
1024 | const char *literal_key = NULL; | |
1025 | int literal_ssh_key = 0; | |
1026 | ||
1027 | if (!signing_key || signing_key[0] == '\0') | |
1028 | return error( | |
1029 | _("user.signingKey needs to be set for ssh signing")); | |
1030 | ||
1031 | if (is_literal_ssh_key(signing_key, &literal_key)) { | |
1032 | /* A literal ssh key */ | |
1033 | literal_ssh_key = 1; | |
1034 | key_file = mks_tempfile_t(".git_signing_key_tmpXXXXXX"); | |
1035 | if (!key_file) | |
1036 | return error_errno( | |
1037 | _("could not create temporary file")); | |
1038 | keylen = strlen(literal_key); | |
1039 | if (write_in_full(key_file->fd, literal_key, keylen) < 0 || | |
1040 | close_tempfile_gently(key_file) < 0) { | |
1041 | error_errno(_("failed writing ssh signing key to '%s'"), | |
1042 | key_file->filename.buf); | |
1043 | goto out; | |
1044 | } | |
1045 | ssh_signing_key_file = strbuf_detach(&key_file->filename, NULL); | |
1046 | } else { | |
1047 | /* We assume a file */ | |
1048 | ssh_signing_key_file = interpolate_path(signing_key, 1); | |
1049 | } | |
1050 | ||
1051 | buffer_file = mks_tempfile_t(".git_signing_buffer_tmpXXXXXX"); | |
1052 | if (!buffer_file) { | |
1053 | error_errno(_("could not create temporary file")); | |
1054 | goto out; | |
1055 | } | |
1056 | ||
1057 | if (write_in_full(buffer_file->fd, buffer->buf, buffer->len) < 0 || | |
1058 | close_tempfile_gently(buffer_file) < 0) { | |
1059 | error_errno(_("failed writing ssh signing key buffer to '%s'"), | |
1060 | buffer_file->filename.buf); | |
1061 | goto out; | |
1062 | } | |
1063 | ||
1064 | strvec_pushl(&signer.args, use_format->program, | |
1065 | "-Y", "sign", | |
1066 | "-n", "git", | |
1067 | "-f", ssh_signing_key_file, | |
1068 | NULL); | |
1069 | if (literal_ssh_key) | |
1070 | strvec_push(&signer.args, "-U"); | |
1071 | strvec_push(&signer.args, buffer_file->filename.buf); | |
1072 | ||
1073 | sigchain_push(SIGPIPE, SIG_IGN); | |
1074 | ret = pipe_command(&signer, NULL, 0, NULL, 0, &signer_stderr, 0); | |
1075 | sigchain_pop(SIGPIPE); | |
1076 | ||
1077 | if (ret) { | |
1078 | if (strstr(signer_stderr.buf, "usage:")) | |
1079 | error(_("ssh-keygen -Y sign is needed for ssh signing (available in openssh version 8.2p1+)")); | |
1080 | ||
1081 | ret = error("%s", signer_stderr.buf); | |
1082 | goto out; | |
1083 | } | |
1084 | ||
1085 | bottom = signature->len; | |
1086 | ||
1087 | strbuf_addbuf(&ssh_signature_filename, &buffer_file->filename); | |
1088 | strbuf_addstr(&ssh_signature_filename, ".sig"); | |
1089 | if (strbuf_read_file(signature, ssh_signature_filename.buf, 0) < 0) { | |
1090 | ret = error_errno( | |
1091 | _("failed reading ssh signing data buffer from '%s'"), | |
1092 | ssh_signature_filename.buf); | |
1093 | goto out; | |
1094 | } | |
1095 | /* Strip CR from the line endings, in case we are on Windows. */ | |
1096 | remove_cr_after(signature, bottom); | |
1097 | ||
1098 | out: | |
1099 | if (key_file) | |
1100 | delete_tempfile(&key_file); | |
1101 | if (buffer_file) | |
1102 | delete_tempfile(&buffer_file); | |
1103 | if (ssh_signature_filename.len) | |
1104 | unlink_or_warn(ssh_signature_filename.buf); | |
1105 | strbuf_release(&signer_stderr); | |
1106 | strbuf_release(&ssh_signature_filename); | |
1107 | FREE_AND_NULL(ssh_signing_key_file); | |
1108 | return ret; | |
1109 | } |