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 };
248 struct got_imsg_fetch_have_refs {
249 	size_t n_have_refs;
250 	/* Followed by n_have_refs times of got_imsg_fetch_have_ref data. */
251 };
252 
253 /* Structures for GOT_IMSG_FETCH_SYMREFS data. */
254 struct got_imsg_fetch_symref {
255 	size_t name_len;
256 	size_t target_len;
257 
258 	/*
259 	 * Followed by name_len + target_len data bytes.
260 	 */
261 } __attribute__((__packed__));
262 
263 struct got_imsg_fetch_symrefs {
264 	size_t nsymrefs;
265 
266 	/* Followed by nsymrefs times of got_imsg_fetch_symref data. */
267 } __attribute__((__packed__));
268 
269 /* Structure for GOT_IMSG_FETCH_REF data. */
270 struct got_imsg_fetch_ref {
271 	/* Describes a reference which will be fetched. */
272 	uint8_t refid[SHA1_DIGEST_LENGTH];
273 	/* Followed by reference name in remaining data of imsg buffer. */
274 };
275 
276 /* Structure for GOT_IMSG_FETCH_DOWNLOAD_PROGRESS data. */
277 struct got_imsg_fetch_download_progress {
278 	/* Number of packfile data bytes downloaded so far. */
279 	off_t packfile_bytes;
280 };
281 
282 /* Structure for GOT_IMSG_IDXPACK_REQUEST data. */
283 struct got_imsg_index_pack_request {
284 	uint8_t pack_hash[SHA1_DIGEST_LENGTH];
285 } __attribute__((__packed__));
286 
287 /* Structure for GOT_IMSG_IDXPACK_PROGRESS data. */
288 struct got_imsg_index_pack_progress {
289 	/* Total number of objects in pack file. */
290 	int nobj_total;
291 
292 	/* Number of objects indexed so far. */
293 	int nobj_indexed;
294 
295 	/* Number of non-deltified objects in pack file. */
296 	int nobj_loose;
297 
298 	/* Number of deltified objects resolved so far. */
299 	int nobj_resolved;
300 };
301 
302 /* Structure for GOT_IMSG_PACKIDX. */
303 struct got_imsg_packidx {
304 	size_t len;
305 	/* Additionally, a file desciptor is passed via imsg. */
306 };
307 
308 /* Structure for GOT_IMSG_PACK. */
309 struct got_imsg_pack {
310 	char path_packfile[PATH_MAX];
311 	size_t filesize;
312 	/* Additionally, a file desciptor is passed via imsg. */
313 } __attribute__((__packed__));
314 
315 /*
316  * Structure for GOT_IMSG_PACKED_OBJECT_REQUEST data.
317  */
318 struct got_imsg_packed_object {
319 	uint8_t id[SHA1_DIGEST_LENGTH];
320 	int idx;
321 } __attribute__((__packed__));
322 
323 /* Structure for GOT_IMSG_COMMIT_TRAVERSAL_REQUEST  */
324 struct got_imsg_commit_traversal_request {
325 	uint8_t id[SHA1_DIGEST_LENGTH];
326 	int idx;
327 	size_t path_len;
328 	/* Followed by path_len bytes of path data */
329 } __attribute__((__packed__));
330 
331 /* Structure for GOT_IMSG_TRAVERSED_COMMITS  */
332 struct got_imsg_traversed_commits {
333 	size_t ncommits;
334 	/* Followed by ncommit IDs of SHA1_DIGEST_LENGTH each */
335 } __attribute__((__packed__));
336 
337 /*
338  * Structure for GOT_IMSG_GITCONFIG_REMOTE data.
339  */
340 struct got_imsg_remote {
341 	size_t name_len;
342 	size_t url_len;
343 
344 	/* Followed by name_len + url_len data bytes. */
345 };
346 
347 /*
348  * Structure for GOT_IMSG_GITCONFIG_REMOTES data.
349  */
350 struct got_imsg_remotes {
351 	int nremotes; /* This many GOT_IMSG_GITCONFIG_REMOTE messages follow. */
352 };
353 
354 struct got_remote_repo;
355 struct got_pack;
356 struct got_packidx;
357 struct got_pathlist_head;
358 
359 const struct got_error *got_send_ack(pid_t);
360 const struct got_error *got_privsep_wait_for_child(pid_t);
361 const struct got_error *got_privsep_send_stop(int);
362 const struct got_error *got_privsep_recv_imsg(struct imsg *, struct imsgbuf *,
363     size_t);
364 void got_privsep_send_error(struct imsgbuf *, const struct got_error *);
365 const struct got_error *got_privsep_send_ack(struct imsgbuf *);
366 const struct got_error *got_privsep_wait_ack(struct imsgbuf *);
367 const struct got_error *got_privsep_send_obj_req(struct imsgbuf *, int);
368 const struct got_error *got_privsep_send_commit_req(struct imsgbuf *, int,
369     struct got_object_id *, int);
370 const struct got_error *got_privsep_send_tree_req(struct imsgbuf *, int,
371     struct got_object_id *, int);
372 const struct got_error *got_privsep_send_tag_req(struct imsgbuf *, int,
373     struct got_object_id *, int);
374 const struct got_error *got_privsep_send_blob_req(struct imsgbuf *, int,
375     struct got_object_id *, int);
376 const struct got_error *got_privsep_send_blob_outfd(struct imsgbuf *, int);
377 const struct got_error *got_privsep_send_tmpfd(struct imsgbuf *, int);
378 const struct got_error *got_privsep_send_obj(struct imsgbuf *,
379     struct got_object *);
380 const struct got_error *got_privsep_send_index_pack_req(struct imsgbuf *,
381     uint8_t *, int);
382 const struct got_error *got_privsep_send_index_pack_outfd(struct imsgbuf *,
383     int);
384 const struct got_error *got_privsep_send_index_pack_progress(struct imsgbuf *,
385     int, int, int, int);
386 const struct got_error *got_privsep_send_index_pack_done(struct imsgbuf *);
387 const struct got_error *got_privsep_recv_index_progress(int *, int *, int *,
388     int *, int *, struct imsgbuf *ibuf);
389 const struct got_error *got_privsep_send_fetch_req(struct imsgbuf *, int,
390     struct got_pathlist_head *);
391 const struct got_error *got_privsep_send_fetch_outfd(struct imsgbuf *, int);
392 const struct got_error *got_privsep_send_fetch_symrefs(struct imsgbuf *,
393     struct got_pathlist_head *);
394 const struct got_error *got_privsep_send_fetch_ref(struct imsgbuf *,
395     struct got_object_id *, const char *);
396 const struct got_error *got_privsep_send_fetch_server_progress(struct imsgbuf *,
397     const char *, size_t);
398 const struct got_error *got_privsep_send_fetch_download_progress(struct imsgbuf *,
399     off_t);
400 const struct got_error *got_privsep_recv_fetch_progress(int *,
401     struct got_object_id **, char **, struct got_pathlist_head *,
402     char **, off_t *, struct imsgbuf *);
403 const struct got_error *got_privsep_send_fetch_done(struct imsgbuf *,
404     struct got_object_id);
405 const struct got_error *got_privsep_get_imsg_obj(struct got_object **,
406     struct imsg *, struct imsgbuf *);
407 const struct got_error *got_privsep_recv_obj(struct got_object **,
408     struct imsgbuf *);
409 const struct got_error *got_privsep_send_commit(struct imsgbuf *,
410     struct got_commit_object *);
411 const struct got_error *got_privsep_recv_commit(struct got_commit_object **,
412     struct imsgbuf *);
413 const struct got_error *got_privsep_recv_tree(struct got_tree_object **,
414     struct imsgbuf *);
415 const struct got_error *got_privsep_send_tree(struct imsgbuf *,
416     struct got_pathlist_head *, int);
417 const struct got_error *got_privsep_send_blob(struct imsgbuf *, size_t, size_t,
418     const uint8_t *);
419 const struct got_error *got_privsep_recv_blob(uint8_t **, size_t *, size_t *,
420     struct imsgbuf *);
421 const struct got_error *got_privsep_send_tag(struct imsgbuf *,
422     struct got_tag_object *);
423 const struct got_error *got_privsep_recv_tag(struct got_tag_object **,
424     struct imsgbuf *);
425 const struct got_error *got_privsep_init_pack_child(struct imsgbuf *,
426     struct got_pack *, struct got_packidx *);
427 const struct got_error *got_privsep_send_packed_obj_req(struct imsgbuf *, int,
428     struct got_object_id *);
429 const struct got_error *got_privsep_send_pack_child_ready(struct imsgbuf *);
430 
431 const struct got_error *got_privsep_send_gitconfig_parse_req(struct imsgbuf *,
432     int);
433 const struct got_error *
434     got_privsep_send_gitconfig_repository_format_version_req(struct imsgbuf *);
435 const struct got_error *got_privsep_send_gitconfig_author_name_req(
436     struct imsgbuf *);
437 const struct got_error *got_privsep_send_gitconfig_author_email_req(
438     struct imsgbuf *);
439 const struct got_error *got_privsep_send_gitconfig_remotes_req(
440     struct imsgbuf *);
441 const struct got_error *got_privsep_send_gitconfig_owner_req(struct imsgbuf *);
442 const struct got_error *got_privsep_send_gitconfig_str(struct imsgbuf *,
443     const char *);
444 const struct got_error *got_privsep_recv_gitconfig_str(char **,
445     struct imsgbuf *);
446 const struct got_error *got_privsep_send_gitconfig_int(struct imsgbuf *, int);
447 const struct got_error *got_privsep_recv_gitconfig_int(int *, struct imsgbuf *);
448 const struct got_error *got_privsep_send_gitconfig_remotes(struct imsgbuf *,
449     struct got_remote_repo *, int);
450 const struct got_error *got_privsep_recv_gitconfig_remotes(
451     struct got_remote_repo **, int *, struct imsgbuf *);
452 
453 const struct got_error *got_privsep_send_commit_traversal_request(
454     struct imsgbuf *, struct got_object_id *, int, const char *);
455 const struct got_error *got_privsep_recv_traversed_commits(
456     struct got_commit_object **, struct got_object_id **,
457     struct got_object_id_queue *, struct imsgbuf *);
458 const struct got_error *got_privsep_send_traversed_commits(
459     struct got_object_id *, size_t, struct imsgbuf *);
460 const struct got_error *got_privsep_send_commit_traversal_done(
461     struct imsgbuf *);
462 
463 void got_privsep_exec_child(int[2], const char *, const char *);