1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  * Copyright (c) 2019, Ori Bernstein <ori@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 /*
19  * All code runs under the same UID but sensitive code paths are
20  * run in a separate process with tighter pledge(2) promises.
21  * Data is communicated between processes via imsg_flush(3) and imsg_read(3).
22  * This behaviour is transparent to users of the library.
23  *
24  * We generally transmit data in imsg buffers, split across several messages
25  * if necessary. File descriptors are used in cases where this is impractical,
26  * such as when accessing pack files or when transferring large blobs.
27  *
28  * We exec(2) after a fork(2). Parts of our library functionality are
29  * accessible via separate executables in a libexec directory.
30  */
31 
32 #define GOT_IMSG_FD_CHILD (STDERR_FILENO + 1)
33 
34 #ifndef GOT_LIBEXECDIR
35 #define GOT_LIBEXECDIR /usr/libexec
36 #endif
37 
38 /* Names of helper programs in libexec directory */
39 #define GOT_PROG_READ_OBJECT	got-read-object
40 #define GOT_PROG_READ_TREE	got-read-tree
41 #define GOT_PROG_READ_COMMIT	got-read-commit
42 #define GOT_PROG_READ_BLOB	got-read-blob
43 #define GOT_PROG_READ_TAG	got-read-tag
44 #define GOT_PROG_READ_PACK	got-read-pack
45 #define GOT_PROG_READ_GITCONFIG	got-read-gitconfig
46 #define GOT_PROG_READ_GOTCONFIG	got-read-gotconfig
47 #define GOT_PROG_FETCH_PACK	got-fetch-pack
48 #define GOT_PROG_INDEX_PACK	got-index-pack
49 #define GOT_PROG_SEND_PACK	got-send-pack
50 
51 #define GOT_STRINGIFY(x) #x
52 #define GOT_STRINGVAL(x) GOT_STRINGIFY(x)
53 
54 /* Paths to helper programs in libexec directory */
55 #define GOT_PATH_PROG_READ_OBJECT \
56 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_OBJECT)
57 #define GOT_PATH_PROG_READ_TREE \
58 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_TREE)
59 #define GOT_PATH_PROG_READ_COMMIT \
60 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_COMMIT)
61 #define GOT_PATH_PROG_READ_BLOB \
62 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_BLOB)
63 #define GOT_PATH_PROG_READ_TAG \
64 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_TAG)
65 #define GOT_PATH_PROG_READ_PACK \
66 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_PACK)
67 #define GOT_PATH_PROG_READ_GITCONFIG \
68 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_GITCONFIG)
69 #define GOT_PATH_PROG_READ_GOTCONFIG \
70 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_GOTCONFIG)
71 #define GOT_PATH_PROG_FETCH_PACK \
72 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_FETCH_PACK)
73 #define GOT_PATH_PROG_SEND_PACK \
74 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_SEND_PACK)
75 #define GOT_PATH_PROG_INDEX_PACK \
76 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_INDEX_PACK)
77 
78 struct got_privsep_child {
79 	int imsg_fd;
80 	pid_t pid;
81 	struct imsgbuf *ibuf;
82 };
83 
84 enum got_imsg_type {
85 	/* An error occured while processing a request. */
86 	GOT_IMSG_ERROR,
87 
88 	/* Stop the child process. */
89 	GOT_IMSG_STOP,
90 
91 	/*
92 	 * Messages concerned with read access to objects in a repository.
93 	 * Object and pack files are opened by the main process, where
94 	 * data may be read as a byte string but without any interpretation.
95 	 * Decompression and parsing of object and pack files occurs in a
96 	 * separate process which runs under pledge("stdio recvfd").
97 	 * This sandboxes our own repository parsing code, as well as zlib.
98 	 */
99 	GOT_IMSG_OBJECT_REQUEST,
100 	GOT_IMSG_OBJECT,
101 	GOT_IMSG_COMMIT_REQUEST,
102 	GOT_IMSG_COMMIT,
103 	GOT_IMSG_COMMIT_LOGMSG,
104 	GOT_IMSG_TREE_REQUEST,
105 	GOT_IMSG_TREE,
106 	GOT_IMSG_TREE_ENTRY,
107 	GOT_IMSG_BLOB_REQUEST,
108 	GOT_IMSG_BLOB_OUTFD,
109 	GOT_IMSG_BLOB,
110 	GOT_IMSG_TAG_REQUEST,
111 	GOT_IMSG_TAG,
112 	GOT_IMSG_TAG_TAGMSG,
113 
114 	/* Messages related to networking. */
115 	GOT_IMSG_FETCH_REQUEST,
116 	GOT_IMSG_FETCH_HAVE_REF,
117 	GOT_IMSG_FETCH_WANTED_BRANCH,
118 	GOT_IMSG_FETCH_WANTED_REF,
119 	GOT_IMSG_FETCH_OUTFD,
120 	GOT_IMSG_FETCH_SYMREFS,
121 	GOT_IMSG_FETCH_REF,
122 	GOT_IMSG_FETCH_SERVER_PROGRESS,
123 	GOT_IMSG_FETCH_DOWNLOAD_PROGRESS,
124 	GOT_IMSG_FETCH_DONE,
125 	GOT_IMSG_IDXPACK_REQUEST,
126 	GOT_IMSG_IDXPACK_OUTFD,
127 	GOT_IMSG_IDXPACK_PROGRESS,
128 	GOT_IMSG_IDXPACK_DONE,
129 
130 	/* Messages related to pack files. */
131 	GOT_IMSG_PACKIDX,
132 	GOT_IMSG_PACK,
133 	GOT_IMSG_PACKED_OBJECT_REQUEST,
134 	GOT_IMSG_COMMIT_TRAVERSAL_REQUEST,
135 	GOT_IMSG_TRAVERSED_COMMITS,
136 	GOT_IMSG_COMMIT_TRAVERSAL_DONE,
137 
138 	/* Message sending file descriptor to a temporary file. */
139 	GOT_IMSG_TMPFD,
140 
141 	/* Messages related to gitconfig files. */
142 	GOT_IMSG_GITCONFIG_PARSE_REQUEST,
143 	GOT_IMSG_GITCONFIG_REPOSITORY_FORMAT_VERSION_REQUEST,
144 	GOT_IMSG_GITCONFIG_AUTHOR_NAME_REQUEST,
145 	GOT_IMSG_GITCONFIG_AUTHOR_EMAIL_REQUEST,
146 	GOT_IMSG_GITCONFIG_REMOTES_REQUEST,
147 	GOT_IMSG_GITCONFIG_INT_VAL,
148 	GOT_IMSG_GITCONFIG_STR_VAL,
149 	GOT_IMSG_GITCONFIG_REMOTES,
150 	GOT_IMSG_GITCONFIG_REMOTE,
151 	GOT_IMSG_GITCONFIG_OWNER_REQUEST,
152 	GOT_IMSG_GITCONFIG_OWNER,
153 
154 	/* Messages related to gotconfig files. */
155 	GOT_IMSG_GOTCONFIG_PARSE_REQUEST,
156 	GOT_IMSG_GOTCONFIG_AUTHOR_REQUEST,
157 	GOT_IMSG_GOTCONFIG_REMOTES_REQUEST,
158 	GOT_IMSG_GOTCONFIG_INT_VAL,
159 	GOT_IMSG_GOTCONFIG_STR_VAL,
160 	GOT_IMSG_GOTCONFIG_REMOTES,
161 	GOT_IMSG_GOTCONFIG_REMOTE,
162 };
163 
164 /* Structure for GOT_IMSG_ERROR. */
165 struct got_imsg_error {
166 	int code; /* an error code from got_error.h */
167 	int errno_code; /* in case code equals GOT_ERR_ERRNO */
168 } __attribute__((__packed__));
169 
170 /*
171  * Structure for GOT_IMSG_TREE_REQUEST and GOT_IMSG_OBJECT data.
172  */
173 struct got_imsg_object {
174 	uint8_t id[SHA1_DIGEST_LENGTH];
175 
176 	/* These fields are the same as in struct got_object. */
177 	int type;
178 	int flags;
179 	size_t hdrlen;
180 	size_t size;
181 	off_t pack_offset;
182 	int pack_idx;
183 }  __attribute__((__packed__));
184 
185 /* Structure for GOT_IMSG_COMMIT data. */
186 struct got_imsg_commit_object {
187 	uint8_t tree_id[SHA1_DIGEST_LENGTH];
188 	size_t author_len;
189 	time_t author_time;
190 	time_t author_gmtoff;
191 	size_t committer_len;
192 	time_t committer_time;
193 	time_t committer_gmtoff;
194 	size_t logmsg_len;
195 	int nparents;
196 
197 	/*
198 	 * Followed by author_len + committer_len data bytes
199 	 */
200 
201 	/* Followed by 'nparents' SHA1_DIGEST_LENGTH length strings */
202 
203 	/*
204 	 * Followed by 'logmsg_len' bytes of commit log message data in
205 	 * one or more GOT_IMSG_COMMIT_LOGMSG messages.
206 	 */
207 } __attribute__((__packed__));
208 
209 
210 /* Structure for GOT_IMSG_TREE_ENTRY. */
211 struct got_imsg_tree_entry {
212 	char id[SHA1_DIGEST_LENGTH];
213 	mode_t mode;
214 	/* Followed by entry's name in remaining data of imsg buffer. */
215 } __attribute__((__packed__));
216 
217 /* Structure for GOT_IMSG_TREE_OBJECT_REPLY data. */
218 struct got_imsg_tree_object {
219 	int nentries; /* This many TREE_ENTRY messages follow. */
220 };
221 
222 /* Structure for GOT_IMSG_BLOB. */
223 struct got_imsg_blob {
224 	size_t size;
225 	size_t hdrlen;
226 
227 	/*
228 	 * If size <= GOT_PRIVSEP_INLINE_BLOB_DATA_MAX, blob data follows
229 	 * in the imsg buffer. Otherwise, blob data has been written to a
230 	 * file descriptor passed via the GOT_IMSG_BLOB_OUTFD imsg.
231 	 */
232 #define GOT_PRIVSEP_INLINE_BLOB_DATA_MAX \
233 	(MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof(struct got_imsg_blob))
234 };
235 
236 
237 /* Structure for GOT_IMSG_TAG data. */
238 struct got_imsg_tag_object {
239 	uint8_t id[SHA1_DIGEST_LENGTH];
240 	int obj_type;
241 	size_t tag_len;
242 	size_t tagger_len;
243 	time_t tagger_time;
244 	time_t tagger_gmtoff;
245 	size_t tagmsg_len;
246 
247 	/*
248 	 * Followed by tag_len + tagger_len data bytes
249 	 */
250 
251 	/*
252 	 * Followed by 'tagmsg_len' bytes of tag message data in
253 	 * one or more GOT_IMSG_TAG_TAGMSG messages.
254 	 */
255 } __attribute__((__packed__));
256 
257 /* Structure for GOT_IMSG_FETCH_HAVE_REF data. */
258 struct got_imsg_fetch_have_ref {
259 	uint8_t id[SHA1_DIGEST_LENGTH];
260 	size_t name_len;
261 	/* Followed by name_len data bytes. */
262 } __attribute__((__packed__));
263 
264 /* Structure for GOT_IMSG_FETCH_WANTED_BRANCH data. */
265 struct got_imsg_fetch_wanted_branch {
266 	size_t name_len;
267 	/* Followed by name_len data bytes. */
268 } __attribute__((__packed__));
269 
270 /* Structure for GOT_IMSG_FETCH_WANTED_REF data. */
271 struct got_imsg_fetch_wanted_ref {
272 	size_t name_len;
273 	/* Followed by name_len data bytes. */
274 } __attribute__((__packed__));
275 
276 /* Structure for GOT_IMSG_FETCH_REQUEST data. */
277 struct got_imsg_fetch_request {
278 	int fetch_all_branches;
279 	int list_refs_only;
280 	int verbosity;
281 	size_t n_have_refs;
282 	size_t n_wanted_branches;
283 	size_t n_wanted_refs;
284 	/* Followed by n_have_refs GOT_IMSG_FETCH_HAVE_REF messages. */
285 	/* Followed by n_wanted_branches times GOT_IMSG_FETCH_WANTED_BRANCH. */
286 	/* Followed by n_wanted_refs times GOT_IMSG_FETCH_WANTED_REF. */
287 } __attribute__((__packed__));
288 
289 /* Structures for GOT_IMSG_FETCH_SYMREFS data. */
290 struct got_imsg_fetch_symref {
291 	size_t name_len;
292 	size_t target_len;
293 
294 	/*
295 	 * Followed by name_len + target_len data bytes.
296 	 */
297 } __attribute__((__packed__));
298 
299 struct got_imsg_fetch_symrefs {
300 	size_t nsymrefs;
301 
302 	/* Followed by nsymrefs times of got_imsg_fetch_symref data. */
303 } __attribute__((__packed__));
304 
305 /* Structure for GOT_IMSG_FETCH_REF data. */
306 struct got_imsg_fetch_ref {
307 	/* Describes a reference which will be fetched. */
308 	uint8_t refid[SHA1_DIGEST_LENGTH];
309 	/* Followed by reference name in remaining data of imsg buffer. */
310 };
311 
312 /* Structure for GOT_IMSG_FETCH_DOWNLOAD_PROGRESS data. */
313 struct got_imsg_fetch_download_progress {
314 	/* Number of packfile data bytes downloaded so far. */
315 	off_t packfile_bytes;
316 };
317 
318 /* Structure for GOT_IMSG_IDXPACK_REQUEST data. */
319 struct got_imsg_index_pack_request {
320 	uint8_t pack_hash[SHA1_DIGEST_LENGTH];
321 } __attribute__((__packed__));
322 
323 /* Structure for GOT_IMSG_IDXPACK_PROGRESS data. */
324 struct got_imsg_index_pack_progress {
325 	/* Total number of objects in pack file. */
326 	int nobj_total;
327 
328 	/* Number of objects indexed so far. */
329 	int nobj_indexed;
330 
331 	/* Number of non-deltified objects in pack file. */
332 	int nobj_loose;
333 
334 	/* Number of deltified objects resolved so far. */
335 	int nobj_resolved;
336 };
337 
338 /* Structure for GOT_IMSG_PACKIDX. */
339 struct got_imsg_packidx {
340 	size_t len;
341 	/* Additionally, a file desciptor is passed via imsg. */
342 };
343 
344 /* Structure for GOT_IMSG_PACK. */
345 struct got_imsg_pack {
346 	char path_packfile[PATH_MAX];
347 	size_t filesize;
348 	/* Additionally, a file desciptor is passed via imsg. */
349 } __attribute__((__packed__));
350 
351 /*
352  * Structure for GOT_IMSG_PACKED_OBJECT_REQUEST data.
353  */
354 struct got_imsg_packed_object {
355 	uint8_t id[SHA1_DIGEST_LENGTH];
356 	int idx;
357 } __attribute__((__packed__));
358 
359 /* Structure for GOT_IMSG_COMMIT_TRAVERSAL_REQUEST  */
360 struct got_imsg_commit_traversal_request {
361 	uint8_t id[SHA1_DIGEST_LENGTH];
362 	int idx;
363 	size_t path_len;
364 	/* Followed by path_len bytes of path data */
365 } __attribute__((__packed__));
366 
367 /* Structure for GOT_IMSG_TRAVERSED_COMMITS  */
368 struct got_imsg_traversed_commits {
369 	size_t ncommits;
370 	/* Followed by ncommit IDs of SHA1_DIGEST_LENGTH each */
371 } __attribute__((__packed__));
372 
373 /*
374  * Structure for GOT_IMSG_GITCONFIG_REMOTE data.
375  */
376 struct got_imsg_remote {
377 	size_t name_len;
378 	size_t url_len;
379 	int mirror_references;
380 
381 	/* Followed by name_len + url_len data bytes. */
382 } __attribute__((__packed__));
383 
384 /*
385  * Structure for GOT_IMSG_GITCONFIG_REMOTES data.
386  */
387 struct got_imsg_remotes {
388 	int nremotes; /* This many GOT_IMSG_GITCONFIG_REMOTE messages follow. */
389 };
390 
391 struct got_remote_repo;
392 struct got_pack;
393 struct got_packidx;
394 struct got_pathlist_head;
395 
396 const struct got_error *got_send_ack(pid_t);
397 const struct got_error *got_privsep_wait_for_child(pid_t);
398 const struct got_error *got_privsep_flush_imsg(struct imsgbuf *);
399 const struct got_error *got_privsep_send_stop(int);
400 const struct got_error *got_privsep_recv_imsg(struct imsg *, struct imsgbuf *,
401     size_t);
402 void got_privsep_send_error(struct imsgbuf *, const struct got_error *);
403 const struct got_error *got_privsep_send_ack(struct imsgbuf *);
404 const struct got_error *got_privsep_wait_ack(struct imsgbuf *);
405 const struct got_error *got_privsep_send_obj_req(struct imsgbuf *, int);
406 const struct got_error *got_privsep_send_commit_req(struct imsgbuf *, int,
407     struct got_object_id *, int);
408 const struct got_error *got_privsep_send_tree_req(struct imsgbuf *, int,
409     struct got_object_id *, int);
410 const struct got_error *got_privsep_send_tag_req(struct imsgbuf *, int,
411     struct got_object_id *, int);
412 const struct got_error *got_privsep_send_blob_req(struct imsgbuf *, int,
413     struct got_object_id *, int);
414 const struct got_error *got_privsep_send_blob_outfd(struct imsgbuf *, int);
415 const struct got_error *got_privsep_send_tmpfd(struct imsgbuf *, int);
416 const struct got_error *got_privsep_send_obj(struct imsgbuf *,
417     struct got_object *);
418 const struct got_error *got_privsep_send_index_pack_req(struct imsgbuf *,
419     uint8_t *, int);
420 const struct got_error *got_privsep_send_index_pack_outfd(struct imsgbuf *,
421     int);
422 const struct got_error *got_privsep_recv_index_progress(int *, int *, int *,
423     int *, int *, struct imsgbuf *ibuf);
424 const struct got_error *got_privsep_send_fetch_req(struct imsgbuf *, int,
425     struct got_pathlist_head *, int, struct got_pathlist_head *,
426     struct got_pathlist_head *, int, int);
427 const struct got_error *got_privsep_send_fetch_outfd(struct imsgbuf *, int);
428 const struct got_error *got_privsep_recv_fetch_progress(int *,
429     struct got_object_id **, char **, struct got_pathlist_head *, char **,
430     off_t *, uint8_t *, struct imsgbuf *);
431 const struct got_error *got_privsep_get_imsg_obj(struct got_object **,
432     struct imsg *, struct imsgbuf *);
433 const struct got_error *got_privsep_recv_obj(struct got_object **,
434     struct imsgbuf *);
435 const struct got_error *got_privsep_send_commit(struct imsgbuf *,
436     struct got_commit_object *);
437 const struct got_error *got_privsep_recv_commit(struct got_commit_object **,
438     struct imsgbuf *);
439 const struct got_error *got_privsep_recv_tree(struct got_tree_object **,
440     struct imsgbuf *);
441 const struct got_error *got_privsep_send_tree(struct imsgbuf *,
442     struct got_pathlist_head *, int);
443 const struct got_error *got_privsep_send_blob(struct imsgbuf *, size_t, size_t,
444     const uint8_t *);
445 const struct got_error *got_privsep_recv_blob(uint8_t **, size_t *, size_t *,
446     struct imsgbuf *);
447 const struct got_error *got_privsep_send_tag(struct imsgbuf *,
448     struct got_tag_object *);
449 const struct got_error *got_privsep_recv_tag(struct got_tag_object **,
450     struct imsgbuf *);
451 const struct got_error *got_privsep_init_pack_child(struct imsgbuf *,
452     struct got_pack *, struct got_packidx *);
453 const struct got_error *got_privsep_send_packed_obj_req(struct imsgbuf *, int,
454     struct got_object_id *);
455 const struct got_error *got_privsep_send_pack_child_ready(struct imsgbuf *);
456 
457 const struct got_error *got_privsep_send_gitconfig_parse_req(struct imsgbuf *,
458     int);
459 const struct got_error *
460     got_privsep_send_gitconfig_repository_format_version_req(struct imsgbuf *);
461 const struct got_error *got_privsep_send_gitconfig_author_name_req(
462     struct imsgbuf *);
463 const struct got_error *got_privsep_send_gitconfig_author_email_req(
464     struct imsgbuf *);
465 const struct got_error *got_privsep_send_gitconfig_remotes_req(
466     struct imsgbuf *);
467 const struct got_error *got_privsep_send_gitconfig_owner_req(struct imsgbuf *);
468 const struct got_error *got_privsep_recv_gitconfig_str(char **,
469     struct imsgbuf *);
470 const struct got_error *got_privsep_recv_gitconfig_int(int *, struct imsgbuf *);
471 const struct got_error *got_privsep_recv_gitconfig_remotes(
472     struct got_remote_repo **, int *, struct imsgbuf *);
473 
474 const struct got_error *got_privsep_send_gotconfig_parse_req(struct imsgbuf *,
475     int);
476 const struct got_error *got_privsep_send_gotconfig_author_req(struct imsgbuf *);
477 const struct got_error *got_privsep_send_gotconfig_remotes_req(
478     struct imsgbuf *);
479 const struct got_error *got_privsep_recv_gotconfig_str(char **,
480     struct imsgbuf *);
481 const struct got_error *got_privsep_recv_gotconfig_remotes(
482     struct got_remote_repo **, int *, struct imsgbuf *);
483 
484 const struct got_error *got_privsep_send_commit_traversal_request(
485     struct imsgbuf *, struct got_object_id *, int, const char *);
486 const struct got_error *got_privsep_recv_traversed_commits(
487     struct got_commit_object **, struct got_object_id **,
488     struct got_object_id_queue *, struct imsgbuf *);
489 
490 void got_privsep_exec_child(int[2], const char *, const char *);