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_OUTFD,
114 	GOT_IMSG_FETCH_SYMREFS,
115 	GOT_IMSG_FETCH_REF,
116 	GOT_IMSG_FETCH_SERVER_PROGRESS,
117 	GOT_IMSG_FETCH_DOWNLOAD_PROGRESS,
118 	GOT_IMSG_FETCH_DONE,
119 	GOT_IMSG_IDXPACK_REQUEST,
120 	GOT_IMSG_IDXPACK_OUTFD,
121 	GOT_IMSG_IDXPACK_PROGRESS,
122 	GOT_IMSG_IDXPACK_DONE,
123 
124 	/* Messages related to pack files. */
125 	GOT_IMSG_PACKIDX,
126 	GOT_IMSG_PACK,
127 	GOT_IMSG_PACKED_OBJECT_REQUEST,
128 	GOT_IMSG_COMMIT_TRAVERSAL_REQUEST,
129 	GOT_IMSG_TRAVERSED_COMMITS,
130 	GOT_IMSG_COMMIT_TRAVERSAL_DONE,
131 
132 	/* Message sending file descriptor to a temporary file. */
133 	GOT_IMSG_TMPFD,
134 
135 	/* Messages related to gitconfig files. */
136 	GOT_IMSG_GITCONFIG_PARSE_REQUEST,
137 	GOT_IMSG_GITCONFIG_REPOSITORY_FORMAT_VERSION_REQUEST,
138 	GOT_IMSG_GITCONFIG_AUTHOR_NAME_REQUEST,
139 	GOT_IMSG_GITCONFIG_AUTHOR_EMAIL_REQUEST,
140 	GOT_IMSG_GITCONFIG_REMOTES_REQUEST,
141 	GOT_IMSG_GITCONFIG_INT_VAL,
142 	GOT_IMSG_GITCONFIG_STR_VAL,
143 	GOT_IMSG_GITCONFIG_REMOTES,
144 	GOT_IMSG_GITCONFIG_REMOTE,
145 	GOT_IMSG_GITCONFIG_OWNER_REQUEST,
146 	GOT_IMSG_GITCONFIG_OWNER,
147 };
148 
149 /* Structure for GOT_IMSG_ERROR. */
150 struct got_imsg_error {
151 	int code; /* an error code from got_error.h */
152 	int errno_code; /* in case code equals GOT_ERR_ERRNO */
153 } __attribute__((__packed__));
154 
155 /*
156  * Structure for GOT_IMSG_TREE_REQUEST and GOT_IMSG_OBJECT data.
157  */
158 struct got_imsg_object {
159 	uint8_t id[SHA1_DIGEST_LENGTH];
160 
161 	/* These fields are the same as in struct got_object. */
162 	int type;
163 	int flags;
164 	size_t hdrlen;
165 	size_t size;
166 	off_t pack_offset;
167 	int pack_idx;
168 }  __attribute__((__packed__));
169 
170 /* Structure for GOT_IMSG_COMMIT data. */
171 struct got_imsg_commit_object {
172 	uint8_t tree_id[SHA1_DIGEST_LENGTH];
173 	size_t author_len;
174 	time_t author_time;
175 	time_t author_gmtoff;
176 	size_t committer_len;
177 	time_t committer_time;
178 	time_t committer_gmtoff;
179 	size_t logmsg_len;
180 	int nparents;
181 
182 	/*
183 	 * Followed by author_len + committer_len data bytes
184 	 */
185 
186 	/* Followed by 'nparents' SHA1_DIGEST_LENGTH length strings */
187 
188 	/*
189 	 * Followed by 'logmsg_len' bytes of commit log message data in
190 	 * one or more GOT_IMSG_COMMIT_LOGMSG messages.
191 	 */
192 } __attribute__((__packed__));
193 
194 
195 /* Structure for GOT_IMSG_TREE_ENTRY. */
196 struct got_imsg_tree_entry {
197 	char id[SHA1_DIGEST_LENGTH];
198 	mode_t mode;
199 	/* Followed by entry's name in remaining data of imsg buffer. */
200 } __attribute__((__packed__));
201 
202 /* Structure for GOT_IMSG_TREE_OBJECT_REPLY data. */
203 struct got_imsg_tree_object {
204 	int nentries; /* This many TREE_ENTRY messages follow. */
205 };
206 
207 /* Structure for GOT_IMSG_BLOB. */
208 struct got_imsg_blob {
209 	size_t size;
210 	size_t hdrlen;
211 
212 	/*
213 	 * If size <= GOT_PRIVSEP_INLINE_BLOB_DATA_MAX, blob data follows
214 	 * in the imsg buffer. Otherwise, blob data has been written to a
215 	 * file descriptor passed via the GOT_IMSG_BLOB_OUTFD imsg.
216 	 */
217 #define GOT_PRIVSEP_INLINE_BLOB_DATA_MAX \
218 	(MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof(struct got_imsg_blob))
219 };
220 
221 
222 /* Structure for GOT_IMSG_TAG data. */
223 struct got_imsg_tag_object {
224 	uint8_t id[SHA1_DIGEST_LENGTH];
225 	int obj_type;
226 	size_t tag_len;
227 	size_t tagger_len;
228 	time_t tagger_time;
229 	time_t tagger_gmtoff;
230 	size_t tagmsg_len;
231 
232 	/*
233 	 * Followed by tag_len + tagger_len data bytes
234 	 */
235 
236 	/*
237 	 * Followed by 'tagmsg_len' bytes of tag message data in
238 	 * one or more GOT_IMSG_TAG_TAGMSG messages.
239 	 */
240 } __attribute__((__packed__));
241 
242 /* Structures for GOT_IMSG_FETCH_REQUEST data. */
243 struct got_imsg_fetch_have_ref {
244 	uint8_t id[SHA1_DIGEST_LENGTH];
245 	size_t name_len;
246 	/* Followed by name_len data bytes. */
247 } __attribute__((__packed__));
248 
249 struct got_imsg_fetch_request {
250 	int fetch_all_branches;
251 	size_t n_have_refs;
252 	/* Followed by n_have_refs times of got_imsg_fetch_have_ref data. */
253 } __attribute__((__packed__));
254 
255 /* Structures for GOT_IMSG_FETCH_SYMREFS data. */
256 struct got_imsg_fetch_symref {
257 	size_t name_len;
258 	size_t target_len;
259 
260 	/*
261 	 * Followed by name_len + target_len data bytes.
262 	 */
263 } __attribute__((__packed__));
264 
265 struct got_imsg_fetch_symrefs {
266 	size_t nsymrefs;
267 
268 	/* Followed by nsymrefs times of got_imsg_fetch_symref data. */
269 } __attribute__((__packed__));
270 
271 /* Structure for GOT_IMSG_FETCH_REF data. */
272 struct got_imsg_fetch_ref {
273 	/* Describes a reference which will be fetched. */
274 	uint8_t refid[SHA1_DIGEST_LENGTH];
275 	/* Followed by reference name in remaining data of imsg buffer. */
276 };
277 
278 /* Structure for GOT_IMSG_FETCH_DOWNLOAD_PROGRESS data. */
279 struct got_imsg_fetch_download_progress {
280 	/* Number of packfile data bytes downloaded so far. */
281 	off_t packfile_bytes;
282 };
283 
284 /* Structure for GOT_IMSG_IDXPACK_REQUEST data. */
285 struct got_imsg_index_pack_request {
286 	uint8_t pack_hash[SHA1_DIGEST_LENGTH];
287 } __attribute__((__packed__));
288 
289 /* Structure for GOT_IMSG_IDXPACK_PROGRESS data. */
290 struct got_imsg_index_pack_progress {
291 	/* Total number of objects in pack file. */
292 	int nobj_total;
293 
294 	/* Number of objects indexed so far. */
295 	int nobj_indexed;
296 
297 	/* Number of non-deltified objects in pack file. */
298 	int nobj_loose;
299 
300 	/* Number of deltified objects resolved so far. */
301 	int nobj_resolved;
302 };
303 
304 /* Structure for GOT_IMSG_PACKIDX. */
305 struct got_imsg_packidx {
306 	size_t len;
307 	/* Additionally, a file desciptor is passed via imsg. */
308 };
309 
310 /* Structure for GOT_IMSG_PACK. */
311 struct got_imsg_pack {
312 	char path_packfile[PATH_MAX];
313 	size_t filesize;
314 	/* Additionally, a file desciptor is passed via imsg. */
315 } __attribute__((__packed__));
316 
317 /*
318  * Structure for GOT_IMSG_PACKED_OBJECT_REQUEST data.
319  */
320 struct got_imsg_packed_object {
321 	uint8_t id[SHA1_DIGEST_LENGTH];
322 	int idx;
323 } __attribute__((__packed__));
324 
325 /* Structure for GOT_IMSG_COMMIT_TRAVERSAL_REQUEST  */
326 struct got_imsg_commit_traversal_request {
327 	uint8_t id[SHA1_DIGEST_LENGTH];
328 	int idx;
329 	size_t path_len;
330 	/* Followed by path_len bytes of path data */
331 } __attribute__((__packed__));
332 
333 /* Structure for GOT_IMSG_TRAVERSED_COMMITS  */
334 struct got_imsg_traversed_commits {
335 	size_t ncommits;
336 	/* Followed by ncommit IDs of SHA1_DIGEST_LENGTH each */
337 } __attribute__((__packed__));
338 
339 /*
340  * Structure for GOT_IMSG_GITCONFIG_REMOTE data.
341  */
342 struct got_imsg_remote {
343 	size_t name_len;
344 	size_t url_len;
345 	int mirror_references;
346 
347 	/* Followed by name_len + url_len data bytes. */
348 };
349 
350 /*
351  * Structure for GOT_IMSG_GITCONFIG_REMOTES data.
352  */
353 struct got_imsg_remotes {
354 	int nremotes; /* This many GOT_IMSG_GITCONFIG_REMOTE messages follow. */
355 };
356 
357 struct got_remote_repo;
358 struct got_pack;
359 struct got_packidx;
360 struct got_pathlist_head;
361 
362 const struct got_error *got_send_ack(pid_t);
363 const struct got_error *got_privsep_wait_for_child(pid_t);
364 const struct got_error *got_privsep_send_stop(int);
365 const struct got_error *got_privsep_recv_imsg(struct imsg *, struct imsgbuf *,
366     size_t);
367 void got_privsep_send_error(struct imsgbuf *, const struct got_error *);
368 const struct got_error *got_privsep_send_ack(struct imsgbuf *);
369 const struct got_error *got_privsep_wait_ack(struct imsgbuf *);
370 const struct got_error *got_privsep_send_obj_req(struct imsgbuf *, int);
371 const struct got_error *got_privsep_send_commit_req(struct imsgbuf *, int,
372     struct got_object_id *, int);
373 const struct got_error *got_privsep_send_tree_req(struct imsgbuf *, int,
374     struct got_object_id *, int);
375 const struct got_error *got_privsep_send_tag_req(struct imsgbuf *, int,
376     struct got_object_id *, int);
377 const struct got_error *got_privsep_send_blob_req(struct imsgbuf *, int,
378     struct got_object_id *, int);
379 const struct got_error *got_privsep_send_blob_outfd(struct imsgbuf *, int);
380 const struct got_error *got_privsep_send_tmpfd(struct imsgbuf *, int);
381 const struct got_error *got_privsep_send_obj(struct imsgbuf *,
382     struct got_object *);
383 const struct got_error *got_privsep_send_index_pack_req(struct imsgbuf *,
384     uint8_t *, int);
385 const struct got_error *got_privsep_send_index_pack_outfd(struct imsgbuf *,
386     int);
387 const struct got_error *got_privsep_send_index_pack_progress(struct imsgbuf *,
388     int, int, int, int);
389 const struct got_error *got_privsep_send_index_pack_done(struct imsgbuf *);
390 const struct got_error *got_privsep_recv_index_progress(int *, int *, int *,
391     int *, int *, struct imsgbuf *ibuf);
392 const struct got_error *got_privsep_send_fetch_req(struct imsgbuf *, int,
393     struct got_pathlist_head *, int);
394 const struct got_error *got_privsep_send_fetch_outfd(struct imsgbuf *, int);
395 const struct got_error *got_privsep_send_fetch_symrefs(struct imsgbuf *,
396     struct got_pathlist_head *);
397 const struct got_error *got_privsep_send_fetch_ref(struct imsgbuf *,
398     struct got_object_id *, const char *);
399 const struct got_error *got_privsep_send_fetch_server_progress(struct imsgbuf *,
400     const char *, size_t);
401 const struct got_error *got_privsep_send_fetch_download_progress(struct imsgbuf *,
402     off_t);
403 const struct got_error *got_privsep_recv_fetch_progress(int *,
404     struct got_object_id **, char **, struct got_pathlist_head *,
405     char **, off_t *, struct imsgbuf *);
406 const struct got_error *got_privsep_send_fetch_done(struct imsgbuf *,
407     struct got_object_id);
408 const struct got_error *got_privsep_get_imsg_obj(struct got_object **,
409     struct imsg *, struct imsgbuf *);
410 const struct got_error *got_privsep_recv_obj(struct got_object **,
411     struct imsgbuf *);
412 const struct got_error *got_privsep_send_commit(struct imsgbuf *,
413     struct got_commit_object *);
414 const struct got_error *got_privsep_recv_commit(struct got_commit_object **,
415     struct imsgbuf *);
416 const struct got_error *got_privsep_recv_tree(struct got_tree_object **,
417     struct imsgbuf *);
418 const struct got_error *got_privsep_send_tree(struct imsgbuf *,
419     struct got_pathlist_head *, int);
420 const struct got_error *got_privsep_send_blob(struct imsgbuf *, size_t, size_t,
421     const uint8_t *);
422 const struct got_error *got_privsep_recv_blob(uint8_t **, size_t *, size_t *,
423     struct imsgbuf *);
424 const struct got_error *got_privsep_send_tag(struct imsgbuf *,
425     struct got_tag_object *);
426 const struct got_error *got_privsep_recv_tag(struct got_tag_object **,
427     struct imsgbuf *);
428 const struct got_error *got_privsep_init_pack_child(struct imsgbuf *,
429     struct got_pack *, struct got_packidx *);
430 const struct got_error *got_privsep_send_packed_obj_req(struct imsgbuf *, int,
431     struct got_object_id *);
432 const struct got_error *got_privsep_send_pack_child_ready(struct imsgbuf *);
433 
434 const struct got_error *got_privsep_send_gitconfig_parse_req(struct imsgbuf *,
435     int);
436 const struct got_error *
437     got_privsep_send_gitconfig_repository_format_version_req(struct imsgbuf *);
438 const struct got_error *got_privsep_send_gitconfig_author_name_req(
439     struct imsgbuf *);
440 const struct got_error *got_privsep_send_gitconfig_author_email_req(
441     struct imsgbuf *);
442 const struct got_error *got_privsep_send_gitconfig_remotes_req(
443     struct imsgbuf *);
444 const struct got_error *got_privsep_send_gitconfig_owner_req(struct imsgbuf *);
445 const struct got_error *got_privsep_send_gitconfig_str(struct imsgbuf *,
446     const char *);
447 const struct got_error *got_privsep_recv_gitconfig_str(char **,
448     struct imsgbuf *);
449 const struct got_error *got_privsep_send_gitconfig_int(struct imsgbuf *, int);
450 const struct got_error *got_privsep_recv_gitconfig_int(int *, struct imsgbuf *);
451 const struct got_error *got_privsep_send_gitconfig_remotes(struct imsgbuf *,
452     struct got_remote_repo *, int);
453 const struct got_error *got_privsep_recv_gitconfig_remotes(
454     struct got_remote_repo **, int *, struct imsgbuf *);
455 
456 const struct got_error *got_privsep_send_commit_traversal_request(
457     struct imsgbuf *, struct got_object_id *, int, const char *);
458 const struct got_error *got_privsep_recv_traversed_commits(
459     struct got_commit_object **, struct got_object_id **,
460     struct got_object_id_queue *, struct imsgbuf *);
461 const struct got_error *got_privsep_send_traversed_commits(
462     struct got_object_id *, size_t, struct imsgbuf *);
463 const struct got_error *got_privsep_send_commit_traversal_done(
464     struct imsgbuf *);
465 
466 void got_privsep_exec_child(int[2], const char *, const char *);