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_FETCH_PACK	got-fetch-pack
47 #define GOT_PROG_INDEX_PACK	got-index-pack
48 #define GOT_PROG_SEND_PACK	got-send-pack
49 
50 #define GOT_STRINGIFY(x) #x
51 #define GOT_STRINGVAL(x) GOT_STRINGIFY(x)
52 
53 /* Paths to helper programs in libexec directory */
54 #define GOT_PATH_PROG_READ_OBJECT \
55 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_OBJECT)
56 #define GOT_PATH_PROG_READ_TREE \
57 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_TREE)
58 #define GOT_PATH_PROG_READ_COMMIT \
59 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_COMMIT)
60 #define GOT_PATH_PROG_READ_BLOB \
61 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_BLOB)
62 #define GOT_PATH_PROG_READ_TAG \
63 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_TAG)
64 #define GOT_PATH_PROG_READ_PACK \
65 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_PACK)
66 #define GOT_PATH_PROG_READ_GITCONFIG \
67 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_GITCONFIG)
68 #define GOT_PATH_PROG_FETCH_PACK \
69 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_FETCH_PACK)
70 #define GOT_PATH_PROG_SEND_PACK \
71 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_SEND_PACK)
72 #define GOT_PATH_PROG_INDEX_PACK \
73 	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_INDEX_PACK)
74 
75 struct got_privsep_child {
76 	int imsg_fd;
77 	pid_t pid;
78 	struct imsgbuf *ibuf;
79 };
80 
81 enum got_imsg_type {
82 	/* An error occured while processing a request. */
83 	GOT_IMSG_ERROR,
84 
85 	/* Stop the child process. */
86 	GOT_IMSG_STOP,
87 
88 	/*
89 	 * Messages concerned with read access to objects in a repository.
90 	 * Object and pack files are opened by the main process, where
91 	 * data may be read as a byte string but without any interpretation.
92 	 * Decompression and parsing of object and pack files occurs in a
93 	 * separate process which runs under pledge("stdio recvfd").
94 	 * This sandboxes our own repository parsing code, as well as zlib.
95 	 */
96 	GOT_IMSG_OBJECT_REQUEST,
97 	GOT_IMSG_OBJECT,
98 	GOT_IMSG_COMMIT_REQUEST,
99 	GOT_IMSG_COMMIT,
100 	GOT_IMSG_COMMIT_LOGMSG,
101 	GOT_IMSG_TREE_REQUEST,
102 	GOT_IMSG_TREE,
103 	GOT_IMSG_TREE_ENTRY,
104 	GOT_IMSG_BLOB_REQUEST,
105 	GOT_IMSG_BLOB_OUTFD,
106 	GOT_IMSG_BLOB,
107 	GOT_IMSG_TAG_REQUEST,
108 	GOT_IMSG_TAG,
109 	GOT_IMSG_TAG_TAGMSG,
110 
111 	/* Messages related to networking. */
112 	GOT_IMSG_FETCH_REQUEST,
113 	GOT_IMSG_FETCH_HAVE_REF,
114 	GOT_IMSG_FETCH_WANTED_BRANCH,
115 	GOT_IMSG_FETCH_OUTFD,
116 	GOT_IMSG_FETCH_SYMREFS,
117 	GOT_IMSG_FETCH_REF,
118 	GOT_IMSG_FETCH_SERVER_PROGRESS,
119 	GOT_IMSG_FETCH_DOWNLOAD_PROGRESS,
120 	GOT_IMSG_FETCH_DONE,
121 	GOT_IMSG_IDXPACK_REQUEST,
122 	GOT_IMSG_IDXPACK_OUTFD,
123 	GOT_IMSG_IDXPACK_PROGRESS,
124 	GOT_IMSG_IDXPACK_DONE,
125 
126 	/* Messages related to pack files. */
127 	GOT_IMSG_PACKIDX,
128 	GOT_IMSG_PACK,
129 	GOT_IMSG_PACKED_OBJECT_REQUEST,
130 	GOT_IMSG_COMMIT_TRAVERSAL_REQUEST,
131 	GOT_IMSG_TRAVERSED_COMMITS,
132 	GOT_IMSG_COMMIT_TRAVERSAL_DONE,
133 
134 	/* Message sending file descriptor to a temporary file. */
135 	GOT_IMSG_TMPFD,
136 
137 	/* Messages related to gitconfig files. */
138 	GOT_IMSG_GITCONFIG_PARSE_REQUEST,
139 	GOT_IMSG_GITCONFIG_REPOSITORY_FORMAT_VERSION_REQUEST,
140 	GOT_IMSG_GITCONFIG_AUTHOR_NAME_REQUEST,
141 	GOT_IMSG_GITCONFIG_AUTHOR_EMAIL_REQUEST,
142 	GOT_IMSG_GITCONFIG_REMOTES_REQUEST,
143 	GOT_IMSG_GITCONFIG_INT_VAL,
144 	GOT_IMSG_GITCONFIG_STR_VAL,
145 	GOT_IMSG_GITCONFIG_REMOTES,
146 	GOT_IMSG_GITCONFIG_REMOTE,
147 	GOT_IMSG_GITCONFIG_OWNER_REQUEST,
148 	GOT_IMSG_GITCONFIG_OWNER,
149 };
150 
151 /* Structure for GOT_IMSG_ERROR. */
152 struct got_imsg_error {
153 	int code; /* an error code from got_error.h */
154 	int errno_code; /* in case code equals GOT_ERR_ERRNO */
155 } __attribute__((__packed__));
156 
157 /*
158  * Structure for GOT_IMSG_TREE_REQUEST and GOT_IMSG_OBJECT data.
159  */
160 struct got_imsg_object {
161 	uint8_t id[SHA1_DIGEST_LENGTH];
162 
163 	/* These fields are the same as in struct got_object. */
164 	int type;
165 	int flags;
166 	size_t hdrlen;
167 	size_t size;
168 	off_t pack_offset;
169 	int pack_idx;
170 }  __attribute__((__packed__));
171 
172 /* Structure for GOT_IMSG_COMMIT data. */
173 struct got_imsg_commit_object {
174 	uint8_t tree_id[SHA1_DIGEST_LENGTH];
175 	size_t author_len;
176 	time_t author_time;
177 	time_t author_gmtoff;
178 	size_t committer_len;
179 	time_t committer_time;
180 	time_t committer_gmtoff;
181 	size_t logmsg_len;
182 	int nparents;
183 
184 	/*
185 	 * Followed by author_len + committer_len data bytes
186 	 */
187 
188 	/* Followed by 'nparents' SHA1_DIGEST_LENGTH length strings */
189 
190 	/*
191 	 * Followed by 'logmsg_len' bytes of commit log message data in
192 	 * one or more GOT_IMSG_COMMIT_LOGMSG messages.
193 	 */
194 } __attribute__((__packed__));
195 
196 
197 /* Structure for GOT_IMSG_TREE_ENTRY. */
198 struct got_imsg_tree_entry {
199 	char id[SHA1_DIGEST_LENGTH];
200 	mode_t mode;
201 	/* Followed by entry's name in remaining data of imsg buffer. */
202 } __attribute__((__packed__));
203 
204 /* Structure for GOT_IMSG_TREE_OBJECT_REPLY data. */
205 struct got_imsg_tree_object {
206 	int nentries; /* This many TREE_ENTRY messages follow. */
207 };
208 
209 /* Structure for GOT_IMSG_BLOB. */
210 struct got_imsg_blob {
211 	size_t size;
212 	size_t hdrlen;
213 
214 	/*
215 	 * If size <= GOT_PRIVSEP_INLINE_BLOB_DATA_MAX, blob data follows
216 	 * in the imsg buffer. Otherwise, blob data has been written to a
217 	 * file descriptor passed via the GOT_IMSG_BLOB_OUTFD imsg.
218 	 */
219 #define GOT_PRIVSEP_INLINE_BLOB_DATA_MAX \
220 	(MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof(struct got_imsg_blob))
221 };
222 
223 
224 /* Structure for GOT_IMSG_TAG data. */
225 struct got_imsg_tag_object {
226 	uint8_t id[SHA1_DIGEST_LENGTH];
227 	int obj_type;
228 	size_t tag_len;
229 	size_t tagger_len;
230 	time_t tagger_time;
231 	time_t tagger_gmtoff;
232 	size_t tagmsg_len;
233 
234 	/*
235 	 * Followed by tag_len + tagger_len data bytes
236 	 */
237 
238 	/*
239 	 * Followed by 'tagmsg_len' bytes of tag message data in
240 	 * one or more GOT_IMSG_TAG_TAGMSG messages.
241 	 */
242 } __attribute__((__packed__));
243 
244 /* Structure for GOT_IMSG_FETCH_HAVE_REF data. */
245 struct got_imsg_fetch_have_ref {
246 	uint8_t id[SHA1_DIGEST_LENGTH];
247 	size_t name_len;
248 	/* Followed by name_len data bytes. */
249 } __attribute__((__packed__));
250 
251 /* Structure for GOT_IMSG_FETCH_WANTED_BRANCH data. */
252 struct got_imsg_fetch_wanted_branch {
253 	size_t name_len;
254 	/* Followed by name_len data bytes. */
255 } __attribute__((__packed__));
256 
257 /* Structure for GOT_IMSG_FETCH_REQUEST data. */
258 struct got_imsg_fetch_request {
259 	int fetch_all_branches;
260 	int list_refs_only;
261 	size_t n_have_refs;
262 	size_t n_wanted_branches;
263 	/* Followed by n_have_refs GOT_IMSG_FETCH_HAVE_REF messages. */
264 	/* Followed by n_wanted_branches times GOT_IMSG_FETCH_WANTED_BRANCH. */
265 } __attribute__((__packed__));
266 
267 /* Structures for GOT_IMSG_FETCH_SYMREFS data. */
268 struct got_imsg_fetch_symref {
269 	size_t name_len;
270 	size_t target_len;
271 
272 	/*
273 	 * Followed by name_len + target_len data bytes.
274 	 */
275 } __attribute__((__packed__));
276 
277 struct got_imsg_fetch_symrefs {
278 	size_t nsymrefs;
279 
280 	/* Followed by nsymrefs times of got_imsg_fetch_symref data. */
281 } __attribute__((__packed__));
282 
283 /* Structure for GOT_IMSG_FETCH_REF data. */
284 struct got_imsg_fetch_ref {
285 	/* Describes a reference which will be fetched. */
286 	uint8_t refid[SHA1_DIGEST_LENGTH];
287 	/* Followed by reference name in remaining data of imsg buffer. */
288 };
289 
290 /* Structure for GOT_IMSG_FETCH_DOWNLOAD_PROGRESS data. */
291 struct got_imsg_fetch_download_progress {
292 	/* Number of packfile data bytes downloaded so far. */
293 	off_t packfile_bytes;
294 };
295 
296 /* Structure for GOT_IMSG_IDXPACK_REQUEST data. */
297 struct got_imsg_index_pack_request {
298 	uint8_t pack_hash[SHA1_DIGEST_LENGTH];
299 } __attribute__((__packed__));
300 
301 /* Structure for GOT_IMSG_IDXPACK_PROGRESS data. */
302 struct got_imsg_index_pack_progress {
303 	/* Total number of objects in pack file. */
304 	int nobj_total;
305 
306 	/* Number of objects indexed so far. */
307 	int nobj_indexed;
308 
309 	/* Number of non-deltified objects in pack file. */
310 	int nobj_loose;
311 
312 	/* Number of deltified objects resolved so far. */
313 	int nobj_resolved;
314 };
315 
316 /* Structure for GOT_IMSG_PACKIDX. */
317 struct got_imsg_packidx {
318 	size_t len;
319 	/* Additionally, a file desciptor is passed via imsg. */
320 };
321 
322 /* Structure for GOT_IMSG_PACK. */
323 struct got_imsg_pack {
324 	char path_packfile[PATH_MAX];
325 	size_t filesize;
326 	/* Additionally, a file desciptor is passed via imsg. */
327 } __attribute__((__packed__));
328 
329 /*
330  * Structure for GOT_IMSG_PACKED_OBJECT_REQUEST data.
331  */
332 struct got_imsg_packed_object {
333 	uint8_t id[SHA1_DIGEST_LENGTH];
334 	int idx;
335 } __attribute__((__packed__));
336 
337 /* Structure for GOT_IMSG_COMMIT_TRAVERSAL_REQUEST  */
338 struct got_imsg_commit_traversal_request {
339 	uint8_t id[SHA1_DIGEST_LENGTH];
340 	int idx;
341 	size_t path_len;
342 	/* Followed by path_len bytes of path data */
343 } __attribute__((__packed__));
344 
345 /* Structure for GOT_IMSG_TRAVERSED_COMMITS  */
346 struct got_imsg_traversed_commits {
347 	size_t ncommits;
348 	/* Followed by ncommit IDs of SHA1_DIGEST_LENGTH each */
349 } __attribute__((__packed__));
350 
351 /*
352  * Structure for GOT_IMSG_GITCONFIG_REMOTE data.
353  */
354 struct got_imsg_remote {
355 	size_t name_len;
356 	size_t url_len;
357 	int mirror_references;
358 
359 	/* Followed by name_len + url_len data bytes. */
360 } __attribute__((__packed__));
361 
362 /*
363  * Structure for GOT_IMSG_GITCONFIG_REMOTES data.
364  */
365 struct got_imsg_remotes {
366 	int nremotes; /* This many GOT_IMSG_GITCONFIG_REMOTE messages follow. */
367 };
368 
369 struct got_remote_repo;
370 struct got_pack;
371 struct got_packidx;
372 struct got_pathlist_head;
373 
374 const struct got_error *got_send_ack(pid_t);
375 const struct got_error *got_privsep_wait_for_child(pid_t);
376 const struct got_error *got_privsep_send_stop(int);
377 const struct got_error *got_privsep_recv_imsg(struct imsg *, struct imsgbuf *,
378     size_t);
379 void got_privsep_send_error(struct imsgbuf *, const struct got_error *);
380 const struct got_error *got_privsep_send_ack(struct imsgbuf *);
381 const struct got_error *got_privsep_wait_ack(struct imsgbuf *);
382 const struct got_error *got_privsep_send_obj_req(struct imsgbuf *, int);
383 const struct got_error *got_privsep_send_commit_req(struct imsgbuf *, int,
384     struct got_object_id *, int);
385 const struct got_error *got_privsep_send_tree_req(struct imsgbuf *, int,
386     struct got_object_id *, int);
387 const struct got_error *got_privsep_send_tag_req(struct imsgbuf *, int,
388     struct got_object_id *, int);
389 const struct got_error *got_privsep_send_blob_req(struct imsgbuf *, int,
390     struct got_object_id *, int);
391 const struct got_error *got_privsep_send_blob_outfd(struct imsgbuf *, int);
392 const struct got_error *got_privsep_send_tmpfd(struct imsgbuf *, int);
393 const struct got_error *got_privsep_send_obj(struct imsgbuf *,
394     struct got_object *);
395 const struct got_error *got_privsep_send_index_pack_req(struct imsgbuf *,
396     uint8_t *, int);
397 const struct got_error *got_privsep_send_index_pack_outfd(struct imsgbuf *,
398     int);
399 const struct got_error *got_privsep_send_index_pack_progress(struct imsgbuf *,
400     int, int, int, int);
401 const struct got_error *got_privsep_send_index_pack_done(struct imsgbuf *);
402 const struct got_error *got_privsep_recv_index_progress(int *, int *, int *,
403     int *, int *, struct imsgbuf *ibuf);
404 const struct got_error *got_privsep_send_fetch_req(struct imsgbuf *, int,
405     struct got_pathlist_head *, int, struct got_pathlist_head *, int);
406 const struct got_error *got_privsep_send_fetch_outfd(struct imsgbuf *, int);
407 const struct got_error *got_privsep_send_fetch_symrefs(struct imsgbuf *,
408     struct got_pathlist_head *);
409 const struct got_error *got_privsep_send_fetch_ref(struct imsgbuf *,
410     struct got_object_id *, const char *);
411 const struct got_error *got_privsep_send_fetch_server_progress(struct imsgbuf *,
412     const char *, size_t);
413 const struct got_error *got_privsep_send_fetch_download_progress(struct imsgbuf *,
414     off_t);
415 const struct got_error *got_privsep_recv_fetch_progress(int *,
416     struct got_object_id **, char **, struct got_pathlist_head *,
417     char **, off_t *, struct imsgbuf *);
418 const struct got_error *got_privsep_send_fetch_done(struct imsgbuf *,
419     struct got_object_id);
420 const struct got_error *got_privsep_get_imsg_obj(struct got_object **,
421     struct imsg *, struct imsgbuf *);
422 const struct got_error *got_privsep_recv_obj(struct got_object **,
423     struct imsgbuf *);
424 const struct got_error *got_privsep_send_commit(struct imsgbuf *,
425     struct got_commit_object *);
426 const struct got_error *got_privsep_recv_commit(struct got_commit_object **,
427     struct imsgbuf *);
428 const struct got_error *got_privsep_recv_tree(struct got_tree_object **,
429     struct imsgbuf *);
430 const struct got_error *got_privsep_send_tree(struct imsgbuf *,
431     struct got_pathlist_head *, int);
432 const struct got_error *got_privsep_send_blob(struct imsgbuf *, size_t, size_t,
433     const uint8_t *);
434 const struct got_error *got_privsep_recv_blob(uint8_t **, size_t *, size_t *,
435     struct imsgbuf *);
436 const struct got_error *got_privsep_send_tag(struct imsgbuf *,
437     struct got_tag_object *);
438 const struct got_error *got_privsep_recv_tag(struct got_tag_object **,
439     struct imsgbuf *);
440 const struct got_error *got_privsep_init_pack_child(struct imsgbuf *,
441     struct got_pack *, struct got_packidx *);
442 const struct got_error *got_privsep_send_packed_obj_req(struct imsgbuf *, int,
443     struct got_object_id *);
444 const struct got_error *got_privsep_send_pack_child_ready(struct imsgbuf *);
445 
446 const struct got_error *got_privsep_send_gitconfig_parse_req(struct imsgbuf *,
447     int);
448 const struct got_error *
449     got_privsep_send_gitconfig_repository_format_version_req(struct imsgbuf *);
450 const struct got_error *got_privsep_send_gitconfig_author_name_req(
451     struct imsgbuf *);
452 const struct got_error *got_privsep_send_gitconfig_author_email_req(
453     struct imsgbuf *);
454 const struct got_error *got_privsep_send_gitconfig_remotes_req(
455     struct imsgbuf *);
456 const struct got_error *got_privsep_send_gitconfig_owner_req(struct imsgbuf *);
457 const struct got_error *got_privsep_send_gitconfig_str(struct imsgbuf *,
458     const char *);
459 const struct got_error *got_privsep_recv_gitconfig_str(char **,
460     struct imsgbuf *);
461 const struct got_error *got_privsep_send_gitconfig_int(struct imsgbuf *, int);
462 const struct got_error *got_privsep_recv_gitconfig_int(int *, struct imsgbuf *);
463 const struct got_error *got_privsep_send_gitconfig_remotes(struct imsgbuf *,
464     struct got_remote_repo *, int);
465 const struct got_error *got_privsep_recv_gitconfig_remotes(
466     struct got_remote_repo **, int *, struct imsgbuf *);
467 
468 const struct got_error *got_privsep_send_commit_traversal_request(
469     struct imsgbuf *, struct got_object_id *, int, const char *);
470 const struct got_error *got_privsep_recv_traversed_commits(
471     struct got_commit_object **, struct got_object_id **,
472     struct got_object_id_queue *, struct imsgbuf *);
473 const struct got_error *got_privsep_send_traversed_commits(
474     struct got_object_id *, size_t, struct imsgbuf *);
475 const struct got_error *got_privsep_send_commit_traversal_done(
476     struct imsgbuf *);
477 
478 void got_privsep_exec_child(int[2], const char *, const char *);