1 /*
2  * Copyright (c) 2022 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "got_compat.h"
18 
19 #define GOTD_UNIX_SOCKET "/var/run/gotd.sock"
20 #define GOTD_UNIX_SOCKET_BACKLOG 10
21 #define GOTD_USER	"_gotd"
22 #define GOTD_CONF_PATH	"/etc/gotd.conf"
23 #define GOTD_EMPTY_PATH	"/var/empty"
24 
25 #define GOTD_MAXCLIENTS		1024
26 #define GOTD_MAX_CONN_PER_UID	4
27 #define GOTD_FD_RESERVE		5
28 #define GOTD_FD_NEEDED		6
29 #define GOTD_FILENO_MSG_PIPE	3
30 
31 #define GOTD_DEFAULT_REQUEST_TIMEOUT	3600
32 
33 /* Client hash tables need some extra room. */
34 #define GOTD_CLIENT_TABLE_SIZE (GOTD_MAXCLIENTS * 4)
35 
36 enum gotd_procid {
37 	PROC_GOTD	= 0,
38 	PROC_LISTEN,
39 	PROC_AUTH,
40 	PROC_SESSION_READ,
41 	PROC_SESSION_WRITE,
42 	PROC_REPO_READ,
43 	PROC_REPO_WRITE,
44 	PROC_GITWRAPPER,
45 	PROC_MAX,
46 };
47 
48 struct gotd_imsgev {
49 	struct imsgbuf	 ibuf;
50 	void		(*handler)(int, short, void *);
51 	void		*handler_arg;
52 	struct event	 ev;
53 	short		 events;
54 };
55 
56 enum gotd_access {
57 	GOTD_ACCESS_PERMITTED = 1,
58 	GOTD_ACCESS_DENIED
59 };
60 
61 struct gotd_access_rule {
62 	STAILQ_ENTRY(gotd_access_rule) entry;
63 
64 	enum gotd_access access;
65 
66 	int authorization;
67 #define GOTD_AUTH_READ		0x1
68 #define GOTD_AUTH_WRITE		0x2
69 
70 	char *identifier;
71 };
72 STAILQ_HEAD(gotd_access_rule_list, gotd_access_rule);
73 
74 struct gotd_repo {
75 	TAILQ_ENTRY(gotd_repo)	 entry;
76 
77 	char name[NAME_MAX];
78 	char path[PATH_MAX];
79 
80 	struct gotd_access_rule_list rules;
81 	struct got_pathlist_head protected_tag_namespaces;
82 	struct got_pathlist_head protected_branch_namespaces;
83 	struct got_pathlist_head protected_branches;
84 };
85 TAILQ_HEAD(gotd_repolist, gotd_repo);
86 
87 enum gotd_session_state {
88 	GOTD_STATE_EXPECT_LIST_REFS,
89 	GOTD_STATE_EXPECT_CAPABILITIES,
90 	GOTD_STATE_EXPECT_WANT,
91 	GOTD_STATE_EXPECT_REF_UPDATE,
92 	GOTD_STATE_EXPECT_MORE_REF_UPDATES,
93 	GOTD_STATE_EXPECT_HAVE,
94 	GOTD_STATE_EXPECT_PACKFILE,
95 	GOTD_STATE_EXPECT_DONE,
96 	GOTD_STATE_DONE,
97 };
98 
99 struct gotd_client_capability {
100 	char *key;
101 	char *value;
102 };
103 
104 struct gotd_object_id_array {
105 	struct got_object_id		**ids;
106 	size_t				 nalloc;
107 	size_t				 nids;
108 };
109 
110 struct gotd_uid_connection_limit {
111 	uid_t uid;
112 	int max_connections;
113 };
114 
115 struct gotd_child_proc;
116 
117 struct gotd {
118 	pid_t pid;
119 	char unix_socket_path[PATH_MAX];
120 	char user_name[32];
121 	struct gotd_repolist repos;
122 	int nrepos;
123 	struct gotd_child_proc *listen_proc;
124 	struct timeval request_timeout;
125 	struct timeval auth_timeout;
126 	struct gotd_uid_connection_limit *connection_limits;
127 	size_t nconnection_limits;
128 
129 	char *argv0;
130 	const char *confpath;
131 	int daemonize;
132 	int verbosity;
133 };
134 
135 enum gotd_imsg_type {
136 	/* An error occured while processing a request. */
137 	GOTD_IMSG_ERROR,
138 
139 	/* Commands used by gotctl(8). */
140 	GOTD_IMSG_INFO,
141 	GOTD_IMSG_INFO_REPO,
142 	GOTD_IMSG_INFO_CLIENT,
143 	GOTD_IMSG_STOP,
144 
145 	/* Request a list of references. */
146 	GOTD_IMSG_LIST_REFS,
147 	GOTD_IMSG_LIST_REFS_INTERNAL,
148 
149 	/* References. */
150 	GOTD_IMSG_REFLIST,
151 	GOTD_IMSG_REF,
152 	GOTD_IMSG_SYMREF,
153 
154 	/* Git protocol capabilities. */
155 	GOTD_IMSG_CAPABILITIES,
156 	GOTD_IMSG_CAPABILITY,
157 
158 	/* Git protocol chatter. */
159 	GOTD_IMSG_WANT,		/* The client wants an object. */
160 	GOTD_IMSG_HAVE,		/* The client has an object. */
161 	GOTD_IMSG_ACK,		/* The server has an object or a reference. */
162 	GOTD_IMSG_NAK,		/* The server does not have an object/ref. */
163 	GOTD_IMSG_REF_UPDATE,	/* The client wants to update a reference. */
164 	GOTD_IMSG_REF_DELETE,	/* The client wants to delete a reference. */
165 	GOTD_IMSG_FLUSH,	/* The client sent a flush packet. */
166 	GOTD_IMSG_DONE,		/* The client is done chatting. */
167 
168 	/* Sending or receiving a pack file. */
169 	GOTD_IMSG_SEND_PACKFILE, /* The server is sending a pack file. */
170 	GOTD_IMSG_RECV_PACKFILE, /* The server is receiving a pack file. */
171 	GOTD_IMSG_PACKIDX_FILE,  /* Temporary file handle for new pack index. */
172 	GOTD_IMSG_PACKFILE_PIPE, /* Pipe to send/receive a pack file stream. */
173 	GOTD_IMSG_PACKFILE_PROGRESS, /* Progress reporting. */
174 	GOTD_IMSG_PACKFILE_READY, /* Pack file is ready to be sent. */
175 	GOTD_IMSG_PACKFILE_STATUS, /* Received pack success/failure status. */
176 	GOTD_IMSG_PACKFILE_INSTALL, /* Received pack file can be installed. */
177 	GOTD_IMSG_PACKFILE_DONE, /* Pack file has been sent/received. */
178 
179 	/* Reference updates. */
180 	GOTD_IMSG_REF_UPDATES_START, /* Ref updates starting. */
181 	GOTD_IMSG_REF_UPDATE_OK, /* Update went OK. */
182 	GOTD_IMSG_REF_UPDATE_NG, /* Update was not good. */
183 	GOTD_IMSG_REFS_UPDATED, /* The server proccessed all ref updates. */
184 
185 	/* Client connections. */
186 	GOTD_IMSG_DISCONNECT,
187 	GOTD_IMSG_CONNECT,
188 
189 	/* Child process management. */
190 	GOTD_IMSG_CLIENT_SESSION_READY,
191 	GOTD_IMSG_REPO_CHILD_READY,
192 	GOTD_IMSG_CONNECT_REPO_CHILD,
193 
194 	/* Auth child process. */
195 	GOTD_IMSG_AUTHENTICATE,
196 	GOTD_IMSG_ACCESS_GRANTED,
197 };
198 
199 /* Structure for GOTD_IMSG_ERROR. */
200 struct gotd_imsg_error {
201 	int code; /* an error code from got_error.h */
202 	int errno_code; /* in case code equals GOT_ERR_ERRNO */
203 	uint32_t client_id;
204 	char msg[GOT_ERR_MAX_MSG_SIZE];
205 } __attribute__((__packed__));
206 
207 /* Structure for GOTD_IMSG_INFO. */
208 struct gotd_imsg_info {
209 	pid_t pid;
210 	int verbosity;
211 	int nrepos;
212 	int nclients;
213 
214 	/* Followed by nrepos GOTD_IMSG_INFO_REPO messages. */
215 	/* Followed by nclients GOTD_IMSG_INFO_CLIENT messages. */
216 };
217 
218 /* Structure for GOTD_IMSG_INFO_REPO. */
219 struct gotd_imsg_info_repo {
220 	char repo_name[NAME_MAX];
221 	char repo_path[PATH_MAX];
222 };
223 
224 /* Structure for GOTD_IMSG_INFO_CLIENT */
225 struct gotd_imsg_info_client {
226 	uid_t euid;
227 	gid_t egid;
228 	char repo_name[NAME_MAX];
229 	int is_writing;
230 	pid_t session_child_pid;
231 	pid_t repo_child_pid;
232 };
233 
234 /* Structure for GOTD_IMSG_LIST_REFS. */
235 struct gotd_imsg_list_refs {
236 	char repo_name[NAME_MAX];
237 	int client_is_reading; /* 1 if reading, 0 if writing */
238 };
239 
240 /* Structure for GOTD_IMSG_LIST_REFS_INTERNAL. */
241 struct gotd_imsg_list_refs_internal {
242 	uint32_t client_id;
243 };
244 
245 /* Structure for GOTD_IMSG_REFLIST. */
246 struct gotd_imsg_reflist {
247 	size_t nrefs;
248 
249 	/* Followed by nrefs times of gotd_imsg_ref/gotd_imsg_symref data. */
250 } __attribute__((__packed__));
251 
252 /* Structure for GOTD_IMSG_REF data. */
253 struct gotd_imsg_ref {
254 	uint8_t id[SHA1_DIGEST_LENGTH];
255 	size_t name_len;
256 	/* Followed by name_len data bytes. */
257 } __attribute__((__packed__));
258 
259 /* Structure for GOTD_IMSG_SYMREF data. */
260 struct gotd_imsg_symref {
261 	size_t name_len;
262 	size_t target_len;
263 	uint8_t target_id[SHA1_DIGEST_LENGTH];
264 
265 	/*
266 	 * Followed by name_len + target_len data bytes.
267 	 */
268 } __attribute__((__packed__));
269 
270 /* Structure for GOTD_IMSG_CAPABILITIES data. */
271 struct gotd_imsg_capabilities {
272 	size_t ncapabilities;
273 
274 	/*
275 	 * Followed by ncapabilities * GOTD_IMSG_CAPABILITY.
276 	 */
277 } __attribute__((__packed__));
278 
279 /* Structure for GOTD_IMSG_CAPABILITY data. */
280 struct gotd_imsg_capability {
281 	size_t key_len;
282 	size_t value_len;
283 
284 	/*
285 	 * Followed by key_len + value_len data bytes.
286 	 */
287 } __attribute__((__packed__));
288 
289 /* Structure for GOTD_IMSG_WANT data. */
290 struct gotd_imsg_want {
291 	uint8_t object_id[SHA1_DIGEST_LENGTH];
292 	uint32_t client_id;
293 } __attribute__((__packed__));
294 
295 /* Structure for GOTD_IMSG_HAVE data. */
296 struct gotd_imsg_have {
297 	uint8_t object_id[SHA1_DIGEST_LENGTH];
298 	uint32_t client_id;
299 } __attribute__((__packed__));
300 
301 /* Structure for GOTD_IMSG_ACK data. */
302 struct gotd_imsg_ack {
303 	uint8_t object_id[SHA1_DIGEST_LENGTH];
304 	uint32_t client_id;
305 } __attribute__((__packed__));
306 
307 /* Structure for GOTD_IMSG_NAK data. */
308 struct gotd_imsg_nak {
309 	uint8_t object_id[SHA1_DIGEST_LENGTH];
310 	uint32_t client_id;
311 } __attribute__((__packed__));
312 
313 /* Structure for GOTD_IMSG_PACKFILE_STATUS data. */
314 struct gotd_imsg_packfile_status {
315 	size_t reason_len;
316 
317 	/* Followed by reason_len data bytes. */
318 } __attribute__((__packed__));
319 
320 
321 /* Structure for GOTD_IMSG_REF_UPDATE data. */
322 struct gotd_imsg_ref_update {
323 	uint8_t old_id[SHA1_DIGEST_LENGTH];
324 	uint8_t new_id[SHA1_DIGEST_LENGTH];
325 	int ref_is_new;
326 	int delete_ref;
327 	uint32_t client_id;
328 	size_t name_len;
329 
330 	/* Followed by name_len data bytes. */
331 } __attribute__((__packed__));
332 
333 /* Structure for GOTD_IMSG_REF_UPDATES_START data. */
334 struct gotd_imsg_ref_updates_start {
335 	int nref_updates;
336 	uint32_t client_id;
337 
338 	/* Followed by nref_updates GOT_IMSG_REF_UPDATE_OK/NG messages. */
339 };
340 
341 /* Structure for GOTD_IMSG_REF_UPDATE_OK data. */
342 struct gotd_imsg_ref_update_ok {
343 	uint8_t old_id[SHA1_DIGEST_LENGTH];
344 	uint8_t new_id[SHA1_DIGEST_LENGTH];
345 	int ref_is_new;
346 	uint32_t client_id;
347 	size_t name_len;
348 
349 	/* Followed by name_len data bytes. */
350 } __attribute__((__packed__));
351 
352 /* Structure for GOTD_IMSG_REF_UPDATE_NG data. */
353 struct gotd_imsg_ref_update_ng {
354 	uint8_t old_id[SHA1_DIGEST_LENGTH];
355 	uint8_t new_id[SHA1_DIGEST_LENGTH];
356 	uint32_t client_id;
357 	size_t name_len;
358 	size_t reason_len;
359 
360 	/* Followed by name_len + reason_len data bytes. */
361 } __attribute__((__packed__));
362 
363 /* Structure for GOTD_IMSG_SEND_PACKFILE data. */
364 struct gotd_imsg_send_packfile {
365 	uint32_t client_id;
366 	int report_progress;
367 
368 	/* delta cache file is sent as a file descriptor */
369 
370 	/* followed by two GOTD_IMSG_PACKFILE_PIPE messages */
371 };
372 
373 /* Structure for GOTD_IMSG_RECV_PACKFILE data. */
374 struct gotd_imsg_recv_packfile {
375 	uint32_t client_id;
376 	int report_status;
377 
378 	/* pack destination temp file is sent as a file descriptor */
379 };
380 
381 /* Structure for GOTD_IMSG_PACKFILE_PIPE data. */
382 struct gotd_imsg_packfile_pipe {
383 	uint32_t client_id;
384 };
385 
386 /* Structure for GOTD_IMSG_PACKIDX_FILE data. */
387 struct gotd_imsg_packidx_file {
388 	uint32_t client_id;
389 };
390 
391 
392 /*
393  * Structure for GOTD_IMSG_PACKFILE_PROGRESS and
394  * GOTD_IMSG_PACKFILE_READY data.
395  */
396 struct gotd_imsg_packfile_progress {
397 	uint32_t client_id;
398 	int ncolored;
399 	int nfound;
400 	int ntrees;
401 	off_t packfile_size;
402 	int ncommits;
403 	int nobj_total;
404 	int nobj_deltify;
405 	int nobj_written;
406 };
407 
408 /* Structure for GOTD_IMSG_PACKFILE_INSTALL. */
409 struct gotd_imsg_packfile_install {
410 	uint32_t client_id;
411 	uint8_t pack_sha1[SHA1_DIGEST_LENGTH];
412 };
413 
414 /* Structure for GOTD_IMSG_PACKFILE_DONE data. */
415 struct gotd_imsg_packfile_done {
416 	uint32_t client_id;
417 };
418 
419 /* Structure for GOTD_IMSG_DISCONNECT data. */
420 struct gotd_imsg_disconnect {
421 	uint32_t client_id;
422 };
423 
424 /* Structure for GOTD_IMSG_CONNECT. */
425 struct gotd_imsg_connect {
426 	uint32_t client_id;
427 	uid_t euid;
428 	gid_t egid;
429 };
430 
431 /* Structure for GOTD_IMSG_CONNECT_REPO_CHILD. */
432 struct gotd_imsg_connect_repo_child {
433 	uint32_t client_id;
434 	enum gotd_procid proc_id;
435 
436 	/* repo child imsg pipe is passed via imsg fd */
437 };
438 
439 /* Structure for GOTD_IMSG_AUTHENTICATE. */
440 struct gotd_imsg_auth {
441 	uid_t euid;
442 	gid_t egid;
443 	int required_auth;
444 	uint32_t client_id;
445 };
446 
447 int parse_config(const char *, enum gotd_procid, struct gotd *);
448 struct gotd_repo *gotd_find_repo_by_name(const char *, struct gotd *);
449 struct gotd_repo *gotd_find_repo_by_path(const char *, struct gotd *);
450 struct gotd_uid_connection_limit *gotd_find_uid_connection_limit(
451     struct gotd_uid_connection_limit *limits, size_t nlimits, uid_t uid);
452 int gotd_parseuid(const char *s, uid_t *uid);
453 
454 /* imsg.c */
455 const struct got_error *gotd_imsg_flush(struct imsgbuf *);
456 const struct got_error *gotd_imsg_recv(struct imsg *, struct imsgbuf *, size_t);
457 const struct got_error *gotd_imsg_poll_recv(struct imsg *, struct imsgbuf *,
458     size_t);
459 const struct got_error *gotd_imsg_recv_error(uint32_t *client_id,
460     struct imsg *imsg);
461 int gotd_imsg_send_error(struct imsgbuf *ibuf, uint32_t, uint32_t,
462     const struct got_error *);
463 int gotd_imsg_send_error_event(struct gotd_imsgev *, uint32_t, uint32_t,
464     const struct got_error *);
465 void gotd_imsg_event_add(struct gotd_imsgev *);
466 int gotd_imsg_compose_event(struct gotd_imsgev *, uint16_t, uint32_t, int,
467     void *, uint16_t);
468 int gotd_imsg_forward(struct gotd_imsgev *, struct imsg *, int);
469 
470 void gotd_imsg_send_ack(struct got_object_id *, struct imsgbuf *,
471     uint32_t, pid_t);
472 void gotd_imsg_send_nak(struct got_object_id *, struct imsgbuf *,
473     uint32_t, pid_t);