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