Merge branch 'mm/push-social-engineering-attack-doc' into next
[git] / send-pack.c
1 #include "builtin.h"
2 #include "commit.h"
3 #include "refs.h"
4 #include "pkt-line.h"
5 #include "sideband.h"
6 #include "run-command.h"
7 #include "remote.h"
8 #include "connect.h"
9 #include "send-pack.h"
10 #include "quote.h"
11 #include "transport.h"
12 #include "version.h"
13 #include "sha1-array.h"
14 #include "gpg-interface.h"
15 #include "cache.h"
16
17 int option_parse_push_signed(const struct option *opt,
18                              const char *arg, int unset)
19 {
20         if (unset) {
21                 *(int *)(opt->value) = SEND_PACK_PUSH_CERT_NEVER;
22                 return 0;
23         }
24         switch (git_parse_maybe_bool(arg)) {
25         case 1:
26                 *(int *)(opt->value) = SEND_PACK_PUSH_CERT_ALWAYS;
27                 return 0;
28         case 0:
29                 *(int *)(opt->value) = SEND_PACK_PUSH_CERT_NEVER;
30                 return 0;
31         }
32         if (!strcasecmp("if-asked", arg)) {
33                 *(int *)(opt->value) = SEND_PACK_PUSH_CERT_IF_ASKED;
34                 return 0;
35         }
36         die("bad %s argument: %s", opt->long_name, arg);
37 }
38
39 static void feed_object(const unsigned char *sha1, FILE *fh, int negative)
40 {
41         if (negative && !has_sha1_file(sha1))
42                 return;
43
44         if (negative)
45                 putc('^', fh);
46         fputs(sha1_to_hex(sha1), fh);
47         putc('\n', fh);
48 }
49
50 /*
51  * Make a pack stream and spit it out into file descriptor fd
52  */
53 static int pack_objects(int fd, struct ref *refs, struct sha1_array *extra, struct send_pack_args *args)
54 {
55         /*
56          * The child becomes pack-objects --revs; we feed
57          * the revision parameters to it via its stdin and
58          * let its stdout go back to the other end.
59          */
60         const char *argv[] = {
61                 "pack-objects",
62                 "--all-progress-implied",
63                 "--revs",
64                 "--stdout",
65                 NULL,
66                 NULL,
67                 NULL,
68                 NULL,
69                 NULL,
70                 NULL,
71         };
72         struct child_process po = CHILD_PROCESS_INIT;
73         FILE *po_in;
74         int i;
75
76         i = 4;
77         if (args->use_thin_pack)
78                 argv[i++] = "--thin";
79         if (args->use_ofs_delta)
80                 argv[i++] = "--delta-base-offset";
81         if (args->quiet || !args->progress)
82                 argv[i++] = "-q";
83         if (args->progress)
84                 argv[i++] = "--progress";
85         if (is_repository_shallow())
86                 argv[i++] = "--shallow";
87         po.argv = argv;
88         po.in = -1;
89         po.out = args->stateless_rpc ? -1 : fd;
90         po.git_cmd = 1;
91         if (start_command(&po))
92                 die_errno("git pack-objects failed");
93
94         /*
95          * We feed the pack-objects we just spawned with revision
96          * parameters by writing to the pipe.
97          */
98         po_in = xfdopen(po.in, "w");
99         for (i = 0; i < extra->nr; i++)
100                 feed_object(extra->sha1[i], po_in, 1);
101
102         while (refs) {
103                 if (!is_null_oid(&refs->old_oid))
104                         feed_object(refs->old_oid.hash, po_in, 1);
105                 if (!is_null_oid(&refs->new_oid))
106                         feed_object(refs->new_oid.hash, po_in, 0);
107                 refs = refs->next;
108         }
109
110         fflush(po_in);
111         if (ferror(po_in))
112                 die_errno("error writing to pack-objects");
113         fclose(po_in);
114
115         if (args->stateless_rpc) {
116                 char *buf = xmalloc(LARGE_PACKET_MAX);
117                 while (1) {
118                         ssize_t n = xread(po.out, buf, LARGE_PACKET_MAX);
119                         if (n <= 0)
120                                 break;
121                         send_sideband(fd, -1, buf, n, LARGE_PACKET_MAX);
122                 }
123                 free(buf);
124                 close(po.out);
125                 po.out = -1;
126         }
127
128         if (finish_command(&po))
129                 return -1;
130         return 0;
131 }
132
133 static int receive_status(int in, struct ref *refs)
134 {
135         struct ref *hint;
136         int ret = 0;
137         char *line = packet_read_line(in, NULL);
138         if (!starts_with(line, "unpack "))
139                 return error("did not receive remote status");
140         if (strcmp(line, "unpack ok")) {
141                 error("unpack failed: %s", line + 7);
142                 ret = -1;
143         }
144         hint = NULL;
145         while (1) {
146                 char *refname;
147                 char *msg;
148                 line = packet_read_line(in, NULL);
149                 if (!line)
150                         break;
151                 if (!starts_with(line, "ok ") && !starts_with(line, "ng ")) {
152                         error("invalid ref status from remote: %s", line);
153                         ret = -1;
154                         break;
155                 }
156
157                 refname = line + 3;
158                 msg = strchr(refname, ' ');
159                 if (msg)
160                         *msg++ = '\0';
161
162                 /* first try searching at our hint, falling back to all refs */
163                 if (hint)
164                         hint = find_ref_by_name(hint, refname);
165                 if (!hint)
166                         hint = find_ref_by_name(refs, refname);
167                 if (!hint) {
168                         warning("remote reported status on unknown ref: %s",
169                                         refname);
170                         continue;
171                 }
172                 if (hint->status != REF_STATUS_EXPECTING_REPORT) {
173                         warning("remote reported status on unexpected ref: %s",
174                                         refname);
175                         continue;
176                 }
177
178                 if (line[0] == 'o' && line[1] == 'k')
179                         hint->status = REF_STATUS_OK;
180                 else {
181                         hint->status = REF_STATUS_REMOTE_REJECT;
182                         ret = -1;
183                 }
184                 hint->remote_status = xstrdup_or_null(msg);
185                 /* start our next search from the next ref */
186                 hint = hint->next;
187         }
188         return ret;
189 }
190
191 static int sideband_demux(int in, int out, void *data)
192 {
193         int *fd = data, ret;
194 #ifdef NO_PTHREADS
195         close(fd[1]);
196 #endif
197         ret = recv_sideband("send-pack", fd[0], out);
198         close(out);
199         return ret;
200 }
201
202 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
203 {
204         struct strbuf *sb = cb;
205         if (graft->nr_parent == -1)
206                 packet_buf_write(sb, "shallow %s\n", oid_to_hex(&graft->oid));
207         return 0;
208 }
209
210 static void advertise_shallow_grafts_buf(struct strbuf *sb)
211 {
212         if (!is_repository_shallow())
213                 return;
214         for_each_commit_graft(advertise_shallow_grafts_cb, sb);
215 }
216
217 #define CHECK_REF_NO_PUSH -1
218 #define CHECK_REF_STATUS_REJECTED -2
219 #define CHECK_REF_UPTODATE -3
220 static int check_to_send_update(const struct ref *ref, const struct send_pack_args *args)
221 {
222         if (!ref->peer_ref && !args->send_mirror)
223                 return CHECK_REF_NO_PUSH;
224
225         /* Check for statuses set by set_ref_status_for_push() */
226         switch (ref->status) {
227         case REF_STATUS_REJECT_NONFASTFORWARD:
228         case REF_STATUS_REJECT_ALREADY_EXISTS:
229         case REF_STATUS_REJECT_FETCH_FIRST:
230         case REF_STATUS_REJECT_NEEDS_FORCE:
231         case REF_STATUS_REJECT_STALE:
232         case REF_STATUS_REJECT_NODELETE:
233                 return CHECK_REF_STATUS_REJECTED;
234         case REF_STATUS_UPTODATE:
235                 return CHECK_REF_UPTODATE;
236         default:
237                 return 0;
238         }
239 }
240
241 /*
242  * the beginning of the next line, or the end of buffer.
243  *
244  * NEEDSWORK: perhaps move this to git-compat-util.h or somewhere and
245  * convert many similar uses found by "git grep -A4 memchr".
246  */
247 static const char *next_line(const char *line, size_t len)
248 {
249         const char *nl = memchr(line, '\n', len);
250         if (!nl)
251                 return line + len; /* incomplete line */
252         return nl + 1;
253 }
254
255 static int generate_push_cert(struct strbuf *req_buf,
256                               const struct ref *remote_refs,
257                               struct send_pack_args *args,
258                               const char *cap_string,
259                               const char *push_cert_nonce)
260 {
261         const struct ref *ref;
262         struct string_list_item *item;
263         char *signing_key = xstrdup(get_signing_key());
264         const char *cp, *np;
265         struct strbuf cert = STRBUF_INIT;
266         int update_seen = 0;
267
268         strbuf_addstr(&cert, "certificate version 0.1\n");
269         strbuf_addf(&cert, "pusher %s ", signing_key);
270         datestamp(&cert);
271         strbuf_addch(&cert, '\n');
272         if (args->url && *args->url) {
273                 char *anon_url = transport_anonymize_url(args->url);
274                 strbuf_addf(&cert, "pushee %s\n", anon_url);
275                 free(anon_url);
276         }
277         if (push_cert_nonce[0])
278                 strbuf_addf(&cert, "nonce %s\n", push_cert_nonce);
279         if (args->push_options)
280                 for_each_string_list_item(item, args->push_options)
281                         strbuf_addf(&cert, "push-option %s\n", item->string);
282         strbuf_addstr(&cert, "\n");
283
284         for (ref = remote_refs; ref; ref = ref->next) {
285                 if (check_to_send_update(ref, args) < 0)
286                         continue;
287                 update_seen = 1;
288                 strbuf_addf(&cert, "%s %s %s\n",
289                             oid_to_hex(&ref->old_oid),
290                             oid_to_hex(&ref->new_oid),
291                             ref->name);
292         }
293         if (!update_seen)
294                 goto free_return;
295
296         if (sign_buffer(&cert, &cert, signing_key))
297                 die(_("failed to sign the push certificate"));
298
299         packet_buf_write(req_buf, "push-cert%c%s", 0, cap_string);
300         for (cp = cert.buf; cp < cert.buf + cert.len; cp = np) {
301                 np = next_line(cp, cert.buf + cert.len - cp);
302                 packet_buf_write(req_buf,
303                                  "%.*s", (int)(np - cp), cp);
304         }
305         packet_buf_write(req_buf, "push-cert-end\n");
306
307 free_return:
308         free(signing_key);
309         strbuf_release(&cert);
310         return update_seen;
311 }
312
313
314 static int atomic_push_failure(struct send_pack_args *args,
315                                struct ref *remote_refs,
316                                struct ref *failing_ref)
317 {
318         struct ref *ref;
319         /* Mark other refs as failed */
320         for (ref = remote_refs; ref; ref = ref->next) {
321                 if (!ref->peer_ref && !args->send_mirror)
322                         continue;
323
324                 switch (ref->status) {
325                 case REF_STATUS_EXPECTING_REPORT:
326                         ref->status = REF_STATUS_ATOMIC_PUSH_FAILED;
327                         continue;
328                 default:
329                         break; /* do nothing */
330                 }
331         }
332         return error("atomic push failed for ref %s. status: %d\n",
333                      failing_ref->name, failing_ref->status);
334 }
335
336 #define NONCE_LEN_LIMIT 256
337
338 static void reject_invalid_nonce(const char *nonce, int len)
339 {
340         int i = 0;
341
342         if (NONCE_LEN_LIMIT <= len)
343                 die("the receiving end asked to sign an invalid nonce <%.*s>",
344                     len, nonce);
345
346         for (i = 0; i < len; i++) {
347                 int ch = nonce[i] & 0xFF;
348                 if (isalnum(ch) ||
349                     ch == '-' || ch == '.' ||
350                     ch == '/' || ch == '+' ||
351                     ch == '=' || ch == '_')
352                         continue;
353                 die("the receiving end asked to sign an invalid nonce <%.*s>",
354                     len, nonce);
355         }
356 }
357
358 int send_pack(struct send_pack_args *args,
359               int fd[], struct child_process *conn,
360               struct ref *remote_refs,
361               struct sha1_array *extra_have)
362 {
363         int in = fd[0];
364         int out = fd[1];
365         struct strbuf req_buf = STRBUF_INIT;
366         struct strbuf cap_buf = STRBUF_INIT;
367         struct ref *ref;
368         int need_pack_data = 0;
369         int allow_deleting_refs = 0;
370         int status_report = 0;
371         int use_sideband = 0;
372         int quiet_supported = 0;
373         int agent_supported = 0;
374         int use_atomic = 0;
375         int atomic_supported = 0;
376         int use_push_options = 0;
377         int push_options_supported = 0;
378         unsigned cmds_sent = 0;
379         int ret;
380         struct async demux;
381         const char *push_cert_nonce = NULL;
382
383         /* Does the other end support the reporting? */
384         if (server_supports("report-status"))
385                 status_report = 1;
386         if (server_supports("delete-refs"))
387                 allow_deleting_refs = 1;
388         if (server_supports("ofs-delta"))
389                 args->use_ofs_delta = 1;
390         if (server_supports("side-band-64k"))
391                 use_sideband = 1;
392         if (server_supports("quiet"))
393                 quiet_supported = 1;
394         if (server_supports("agent"))
395                 agent_supported = 1;
396         if (server_supports("no-thin"))
397                 args->use_thin_pack = 0;
398         if (server_supports("atomic"))
399                 atomic_supported = 1;
400         if (server_supports("push-options"))
401                 push_options_supported = 1;
402
403         if (args->push_cert != SEND_PACK_PUSH_CERT_NEVER) {
404                 int len;
405                 push_cert_nonce = server_feature_value("push-cert", &len);
406                 if (push_cert_nonce) {
407                         reject_invalid_nonce(push_cert_nonce, len);
408                         push_cert_nonce = xmemdupz(push_cert_nonce, len);
409                 } else if (args->push_cert == SEND_PACK_PUSH_CERT_ALWAYS) {
410                         die(_("the receiving end does not support --signed push"));
411                 } else if (args->push_cert == SEND_PACK_PUSH_CERT_IF_ASKED) {
412                         warning(_("not sending a push certificate since the"
413                                   " receiving end does not support --signed"
414                                   " push"));
415                 }
416         }
417
418         if (!remote_refs) {
419                 fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
420                         "Perhaps you should specify a branch such as 'master'.\n");
421                 return 0;
422         }
423         if (args->atomic && !atomic_supported)
424                 die(_("the receiving end does not support --atomic push"));
425
426         use_atomic = atomic_supported && args->atomic;
427
428         if (args->push_options && !push_options_supported)
429                 die(_("the receiving end does not support push options"));
430
431         use_push_options = push_options_supported && args->push_options;
432
433         if (status_report)
434                 strbuf_addstr(&cap_buf, " report-status");
435         if (use_sideband)
436                 strbuf_addstr(&cap_buf, " side-band-64k");
437         if (quiet_supported && (args->quiet || !args->progress))
438                 strbuf_addstr(&cap_buf, " quiet");
439         if (use_atomic)
440                 strbuf_addstr(&cap_buf, " atomic");
441         if (use_push_options)
442                 strbuf_addstr(&cap_buf, " push-options");
443         if (agent_supported)
444                 strbuf_addf(&cap_buf, " agent=%s", git_user_agent_sanitized());
445
446         /*
447          * NEEDSWORK: why does delete-refs have to be so specific to
448          * send-pack machinery that set_ref_status_for_push() cannot
449          * set this bit for us???
450          */
451         for (ref = remote_refs; ref; ref = ref->next)
452                 if (ref->deletion && !allow_deleting_refs)
453                         ref->status = REF_STATUS_REJECT_NODELETE;
454
455         if (!args->dry_run)
456                 advertise_shallow_grafts_buf(&req_buf);
457
458         if (!args->dry_run && push_cert_nonce)
459                 cmds_sent = generate_push_cert(&req_buf, remote_refs, args,
460                                                cap_buf.buf, push_cert_nonce);
461
462         /*
463          * Clear the status for each ref and see if we need to send
464          * the pack data.
465          */
466         for (ref = remote_refs; ref; ref = ref->next) {
467                 switch (check_to_send_update(ref, args)) {
468                 case 0: /* no error */
469                         break;
470                 case CHECK_REF_STATUS_REJECTED:
471                         /*
472                          * When we know the server would reject a ref update if
473                          * we were to send it and we're trying to send the refs
474                          * atomically, abort the whole operation.
475                          */
476                         if (use_atomic)
477                                 return atomic_push_failure(args, remote_refs, ref);
478                         /* Fallthrough for non atomic case. */
479                 default:
480                         continue;
481                 }
482                 if (!ref->deletion)
483                         need_pack_data = 1;
484
485                 if (args->dry_run || !status_report)
486                         ref->status = REF_STATUS_OK;
487                 else
488                         ref->status = REF_STATUS_EXPECTING_REPORT;
489         }
490
491         /*
492          * Finally, tell the other end!
493          */
494         for (ref = remote_refs; ref; ref = ref->next) {
495                 char *old_hex, *new_hex;
496
497                 if (args->dry_run || push_cert_nonce)
498                         continue;
499
500                 if (check_to_send_update(ref, args) < 0)
501                         continue;
502
503                 old_hex = oid_to_hex(&ref->old_oid);
504                 new_hex = oid_to_hex(&ref->new_oid);
505                 if (!cmds_sent) {
506                         packet_buf_write(&req_buf,
507                                          "%s %s %s%c%s",
508                                          old_hex, new_hex, ref->name, 0,
509                                          cap_buf.buf);
510                         cmds_sent = 1;
511                 } else {
512                         packet_buf_write(&req_buf, "%s %s %s",
513                                          old_hex, new_hex, ref->name);
514                 }
515         }
516
517         if (args->stateless_rpc) {
518                 if (!args->dry_run && (cmds_sent || is_repository_shallow())) {
519                         packet_buf_flush(&req_buf);
520                         send_sideband(out, -1, req_buf.buf, req_buf.len, LARGE_PACKET_MAX);
521                 }
522         } else {
523                 write_or_die(out, req_buf.buf, req_buf.len);
524                 packet_flush(out);
525         }
526         strbuf_release(&req_buf);
527         strbuf_release(&cap_buf);
528
529         if (use_push_options) {
530                 struct string_list_item *item;
531                 struct strbuf sb = STRBUF_INIT;
532
533                 for_each_string_list_item(item, args->push_options)
534                         packet_buf_write(&sb, "%s", item->string);
535
536                 write_or_die(out, sb.buf, sb.len);
537                 packet_flush(out);
538                 strbuf_release(&sb);
539         }
540
541         if (use_sideband && cmds_sent) {
542                 memset(&demux, 0, sizeof(demux));
543                 demux.proc = sideband_demux;
544                 demux.data = fd;
545                 demux.out = -1;
546                 demux.isolate_sigpipe = 1;
547                 if (start_async(&demux))
548                         die("send-pack: unable to fork off sideband demultiplexer");
549                 in = demux.out;
550         }
551
552         if (need_pack_data && cmds_sent) {
553                 if (pack_objects(out, remote_refs, extra_have, args) < 0) {
554                         for (ref = remote_refs; ref; ref = ref->next)
555                                 ref->status = REF_STATUS_NONE;
556                         if (args->stateless_rpc)
557                                 close(out);
558                         if (git_connection_is_socket(conn))
559                                 shutdown(fd[0], SHUT_WR);
560                         if (use_sideband) {
561                                 close(demux.out);
562                                 finish_async(&demux);
563                         }
564                         fd[1] = -1;
565                         return -1;
566                 }
567                 if (!args->stateless_rpc)
568                         /* Closed by pack_objects() via start_command() */
569                         fd[1] = -1;
570         }
571         if (args->stateless_rpc && cmds_sent)
572                 packet_flush(out);
573
574         if (status_report && cmds_sent)
575                 ret = receive_status(in, remote_refs);
576         else
577                 ret = 0;
578         if (args->stateless_rpc)
579                 packet_flush(out);
580
581         if (use_sideband && cmds_sent) {
582                 close(demux.out);
583                 if (finish_async(&demux)) {
584                         error("error in sideband demultiplexer");
585                         ret = -1;
586                 }
587         }
588
589         if (ret < 0)
590                 return ret;
591
592         if (args->porcelain)
593                 return 0;
594
595         for (ref = remote_refs; ref; ref = ref->next) {
596                 switch (ref->status) {
597                 case REF_STATUS_NONE:
598                 case REF_STATUS_UPTODATE:
599                 case REF_STATUS_OK:
600                         break;
601                 default:
602                         return -1;
603                 }
604         }
605         return 0;
606 }