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_DONE,
114 	GOT_IMSG_IDXPACK_REQUEST,
115 	GOT_IMSG_IDXPACK_DONE,
116 
117 	/* Messages related to pack files. */
118 	GOT_IMSG_PACKIDX,
119 	GOT_IMSG_PACK,
120 	GOT_IMSG_PACKED_OBJECT_REQUEST,
121 	GOT_IMSG_COMMIT_TRAVERSAL_REQUEST,
122 	GOT_IMSG_TRAVERSED_COMMITS,
123 	GOT_IMSG_COMMIT_TRAVERSAL_DONE,
124 
125 	/* Message sending file descriptor to a temporary file. */
126 	GOT_IMSG_TMPFD,
127 
128 	/* Messages related to gitconfig files. */
129 	GOT_IMSG_GITCONFIG_PARSE_REQUEST,
130 	GOT_IMSG_GITCONFIG_REPOSITORY_FORMAT_VERSION_REQUEST,
131 	GOT_IMSG_GITCONFIG_AUTHOR_NAME_REQUEST,
132 	GOT_IMSG_GITCONFIG_AUTHOR_EMAIL_REQUEST,
133 	GOT_IMSG_GITCONFIG_REMOTES_REQUEST,
134 	GOT_IMSG_GITCONFIG_INT_VAL,
135 	GOT_IMSG_GITCONFIG_STR_VAL,
136 	GOT_IMSG_GITCONFIG_REMOTES,
137 	GOT_IMSG_GITCONFIG_REMOTE,
138 	GOT_IMSG_GITCONFIG_OWNER_REQUEST,
139 	GOT_IMSG_GITCONFIG_OWNER,
140 };
141 
142 /* Structure for GOT_IMSG_ERROR. */
143 struct got_imsg_error {
144 	int code; /* an error code from got_error.h */
145 	int errno_code; /* in case code equals GOT_ERR_ERRNO */
146 } __attribute__((__packed__));
147 
148 /*
149  * Structure for GOT_IMSG_TREE_REQUEST and GOT_IMSG_OBJECT data.
150  */
151 struct got_imsg_object {
152 	uint8_t id[SHA1_DIGEST_LENGTH];
153 
154 	/* These fields are the same as in struct got_object. */
155 	int type;
156 	int flags;
157 	size_t hdrlen;
158 	size_t size;
159 	off_t pack_offset;
160 	int pack_idx;
161 }  __attribute__((__packed__));
162 
163 /* Structure for GOT_IMSG_COMMIT data. */
164 struct got_imsg_commit_object {
165 	uint8_t tree_id[SHA1_DIGEST_LENGTH];
166 	size_t author_len;
167 	time_t author_time;
168 	time_t author_gmtoff;
169 	size_t committer_len;
170 	time_t committer_time;
171 	time_t committer_gmtoff;
172 	size_t logmsg_len;
173 	int nparents;
174 
175 	/*
176 	 * Followed by author_len + committer_len data bytes
177 	 */
178 
179 	/* Followed by 'nparents' SHA1_DIGEST_LENGTH length strings */
180 
181 	/*
182 	 * Followed by 'logmsg_len' bytes of commit log message data in
183 	 * one or more GOT_IMSG_COMMIT_LOGMSG messages.
184 	 */
185 } __attribute__((__packed__));
186 
187 
188 /* Structure for GOT_IMSG_TREE_ENTRY. */
189 struct got_imsg_tree_entry {
190 	char id[SHA1_DIGEST_LENGTH];
191 	mode_t mode;
192 	/* Followed by entry's name in remaining data of imsg buffer. */
193 } __attribute__((__packed__));
194 
195 /* Structure for GOT_IMSG_TREE_OBJECT_REPLY data. */
196 struct got_imsg_tree_object {
197 	int nentries; /* This many TREE_ENTRY messages follow. */
198 };
199 
200 /* Structure for GOT_IMSG_BLOB. */
201 struct got_imsg_blob {
202 	size_t size;
203 	size_t hdrlen;
204 
205 	/*
206 	 * If size <= GOT_PRIVSEP_INLINE_BLOB_DATA_MAX, blob data follows
207 	 * in the imsg buffer. Otherwise, blob data has been written to a
208 	 * file descriptor passed via the GOT_IMSG_BLOB_OUTFD imsg.
209 	 */
210 #define GOT_PRIVSEP_INLINE_BLOB_DATA_MAX \
211 	(MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof(struct got_imsg_blob))
212 };
213 
214 
215 /* Structure for GOT_IMSG_TAG data. */
216 struct got_imsg_tag_object {
217 	uint8_t id[SHA1_DIGEST_LENGTH];
218 	int obj_type;
219 	size_t tag_len;
220 	size_t tagger_len;
221 	time_t tagger_time;
222 	time_t tagger_gmtoff;
223 	size_t tagmsg_len;
224 
225 	/*
226 	 * Followed by tag_len + tagger_len data bytes
227 	 */
228 
229 	/*
230 	 * Followed by 'tagmsg_len' bytes of tag message data in
231 	 * one or more GOT_IMSG_TAG_TAGMSG messages.
232 	 */
233 } __attribute__((__packed__));
234 
235 /* Structure for GOT_IMSG_PACKIDX. */
236 struct got_imsg_packidx {
237 	size_t len;
238 	/* Additionally, a file desciptor is passed via imsg. */
239 };
240 
241 /* Structure for GOT_IMSG_PACK. */
242 struct got_imsg_pack {
243 	char path_packfile[PATH_MAX];
244 	size_t filesize;
245 	/* Additionally, a file desciptor is passed via imsg. */
246 } __attribute__((__packed__));
247 
248 /*
249  * Structure for GOT_IMSG_PACKED_OBJECT_REQUEST data.
250  */
251 struct got_imsg_packed_object {
252 	uint8_t id[SHA1_DIGEST_LENGTH];
253 	int idx;
254 } __attribute__((__packed__));
255 
256 /* Structure for GOT_IMSG_COMMIT_TRAVERSAL_REQUEST  */
257 struct got_imsg_commit_traversal_request {
258 	uint8_t id[SHA1_DIGEST_LENGTH];
259 	int idx;
260 	size_t path_len;
261 	/* Followed by path_len bytes of path data */
262 } __attribute__((__packed__));
263 
264 /* Structure for GOT_IMSG_TRAVERSED_COMMITS  */
265 struct got_imsg_traversed_commits {
266 	size_t ncommits;
267 	/* Followed by ncommit IDs of SHA1_DIGEST_LENGTH each */
268 } __attribute__((__packed__));
269 
270 /*
271  * Structure for GOT_IMSG_GITCONFIG_REMOTE data.
272  */
273 struct got_imsg_remote {
274 	size_t name_len;
275 	size_t url_len;
276 
277 	/* Followed by name_len + url_len data bytes. */
278 };
279 
280 /*
281  * Structure for GOT_IMSG_GITCONFIG_REMOTES data.
282  */
283 struct got_imsg_remotes {
284 	int nremotes; /* This many GOT_IMSG_GITCONFIG_REMOTE messages follow. */
285 };
286 
287 struct got_remote_repo;
288 struct got_pack;
289 struct got_packidx;
290 struct got_pathlist_head;
291 
292 const struct got_error *got_send_ack(pid_t);
293 const struct got_error *got_privsep_wait_for_child(pid_t);
294 const struct got_error *got_privsep_send_stop(int);
295 const struct got_error *got_privsep_recv_imsg(struct imsg *, struct imsgbuf *,
296     size_t);
297 void got_privsep_send_error(struct imsgbuf *, const struct got_error *);
298 const struct got_error *got_privsep_send_ack(struct imsgbuf *);
299 const struct got_error *got_privsep_wait_ack(struct imsgbuf *);
300 const struct got_error *got_privsep_send_obj_req(struct imsgbuf *, int);
301 const struct got_error *got_privsep_send_commit_req(struct imsgbuf *, int,
302     struct got_object_id *, int);
303 const struct got_error *got_privsep_send_tree_req(struct imsgbuf *, int,
304     struct got_object_id *, int);
305 const struct got_error *got_privsep_send_tag_req(struct imsgbuf *, int,
306     struct got_object_id *, int);
307 const struct got_error *got_privsep_send_blob_req(struct imsgbuf *, int,
308     struct got_object_id *, int);
309 const struct got_error *got_privsep_send_blob_outfd(struct imsgbuf *, int);
310 const struct got_error *got_privsep_send_tmpfd(struct imsgbuf *, int);
311 const struct got_error *got_privsep_send_obj(struct imsgbuf *,
312     struct got_object *);
313 const struct got_error *got_privsep_send_index_pack_req(struct imsgbuf *, int,
314     struct got_object_id *);
315 const struct got_error *got_privsep_send_index_pack_done(struct imsgbuf *);
316 const struct got_error *got_privsep_wait_index_pack_done(struct imsgbuf *);
317 const struct got_error *got_privsep_send_fetch_req(struct imsgbuf *, int);
318 const struct got_error *got_privsep_send_fetch_done(struct imsgbuf *,
319     struct got_object_id);
320 const struct got_error *got_privsep_wait_fetch_done(struct imsgbuf *,
321     struct got_object_id*);
322 const struct got_error *got_privsep_get_imsg_obj(struct got_object **,
323     struct imsg *, struct imsgbuf *);
324 const struct got_error *got_privsep_recv_obj(struct got_object **,
325     struct imsgbuf *);
326 const struct got_error *got_privsep_send_commit(struct imsgbuf *,
327     struct got_commit_object *);
328 const struct got_error *got_privsep_recv_commit(struct got_commit_object **,
329     struct imsgbuf *);
330 const struct got_error *got_privsep_recv_tree(struct got_tree_object **,
331     struct imsgbuf *);
332 const struct got_error *got_privsep_send_tree(struct imsgbuf *,
333     struct got_pathlist_head *, int);
334 const struct got_error *got_privsep_send_blob(struct imsgbuf *, size_t, size_t,
335     const uint8_t *);
336 const struct got_error *got_privsep_recv_blob(uint8_t **, size_t *, size_t *,
337     struct imsgbuf *);
338 const struct got_error *got_privsep_send_tag(struct imsgbuf *,
339     struct got_tag_object *);
340 const struct got_error *got_privsep_recv_tag(struct got_tag_object **,
341     struct imsgbuf *);
342 const struct got_error *got_privsep_init_pack_child(struct imsgbuf *,
343     struct got_pack *, struct got_packidx *);
344 const struct got_error *got_privsep_send_packed_obj_req(struct imsgbuf *, int,
345     struct got_object_id *);
346 const struct got_error *got_privsep_send_pack_child_ready(struct imsgbuf *);
347 
348 const struct got_error *got_privsep_send_gitconfig_parse_req(struct imsgbuf *,
349     int);
350 const struct got_error *
351     got_privsep_send_gitconfig_repository_format_version_req(struct imsgbuf *);
352 const struct got_error *got_privsep_send_gitconfig_author_name_req(
353     struct imsgbuf *);
354 const struct got_error *got_privsep_send_gitconfig_author_email_req(
355     struct imsgbuf *);
356 const struct got_error *got_privsep_send_gitconfig_remotes_req(
357     struct imsgbuf *);
358 const struct got_error *got_privsep_send_gitconfig_owner_req(struct imsgbuf *);
359 const struct got_error *got_privsep_send_gitconfig_str(struct imsgbuf *,
360     const char *);
361 const struct got_error *got_privsep_recv_gitconfig_str(char **,
362     struct imsgbuf *);
363 const struct got_error *got_privsep_send_gitconfig_int(struct imsgbuf *, int);
364 const struct got_error *got_privsep_recv_gitconfig_int(int *, struct imsgbuf *);
365 const struct got_error *got_privsep_send_gitconfig_remotes(struct imsgbuf *,
366     struct got_remote_repo *, int);
367 const struct got_error *got_privsep_recv_gitconfig_remotes(
368     struct got_remote_repo **, int *, struct imsgbuf *);
369 
370 const struct got_error *got_privsep_send_commit_traversal_request(
371     struct imsgbuf *, struct got_object_id *, int, const char *);
372 const struct got_error *got_privsep_recv_traversed_commits(
373     struct got_commit_object **, struct got_object_id **,
374     struct got_object_id_queue *, struct imsgbuf *);
375 const struct got_error *got_privsep_send_traversed_commits(
376     struct got_object_id *, size_t, struct imsgbuf *);
377 const struct got_error *got_privsep_send_commit_traversal_done(
378     struct imsgbuf *);
379 
380 void got_privsep_exec_child(int[2], const char *, const char *);