1 2b3d32a1 2022-12-30 thomas /*
  2 2b3d32a1 2022-12-30 thomas  * Copyright (c) 2022 Stefan Sperling <stsp@openbsd.org>
  3 2b3d32a1 2022-12-30 thomas  *
  4 2b3d32a1 2022-12-30 thomas  * Permission to use, copy, modify, and distribute this software for any
  5 2b3d32a1 2022-12-30 thomas  * purpose with or without fee is hereby granted, provided that the above
  6 2b3d32a1 2022-12-30 thomas  * copyright notice and this permission notice appear in all copies.
  7 2b3d32a1 2022-12-30 thomas  *
  8 2b3d32a1 2022-12-30 thomas  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 2b3d32a1 2022-12-30 thomas  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 2b3d32a1 2022-12-30 thomas  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 2b3d32a1 2022-12-30 thomas  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 2b3d32a1 2022-12-30 thomas  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 2b3d32a1 2022-12-30 thomas  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 2b3d32a1 2022-12-30 thomas  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 2b3d32a1 2022-12-30 thomas  */
 16 2b3d32a1 2022-12-30 thomas 
 17 2b3d32a1 2022-12-30 thomas #include <sys/types.h>
 18 2b3d32a1 2022-12-30 thomas #include <sys/queue.h>
 19 2b3d32a1 2022-12-30 thomas #include <sys/socket.h>
 20 2b3d32a1 2022-12-30 thomas #include <sys/uio.h>
 21 2b3d32a1 2022-12-30 thomas 
 22 2b3d32a1 2022-12-30 thomas #include <errno.h>
 23 2b3d32a1 2022-12-30 thomas #include <event.h>
 24 2b3d32a1 2022-12-30 thomas #include <stdint.h>
 25 2b3d32a1 2022-12-30 thomas #include <stdio.h>
 26 2b3d32a1 2022-12-30 thomas #include <stdlib.h>
 27 2b3d32a1 2022-12-30 thomas #include <string.h>
 28 2b3d32a1 2022-12-30 thomas #include <imsg.h>
 29 2b3d32a1 2022-12-30 thomas #include <limits.h>
 30 2b3d32a1 2022-12-30 thomas #include <signal.h>
 31 2b3d32a1 2022-12-30 thomas #include <unistd.h>
 32 2b3d32a1 2022-12-30 thomas 
 33 2b3d32a1 2022-12-30 thomas #include "got_error.h"
 34 6d7eb4f7 2023-04-04 thomas #include "got_path.h"
 35 2b3d32a1 2022-12-30 thomas 
 36 621b8de0 2023-08-23 thomas #include "got_compat.h"
 37 621b8de0 2023-08-23 thomas 
 38 2b3d32a1 2022-12-30 thomas #include "gotd.h"
 39 2b3d32a1 2022-12-30 thomas #include "log.h"
 40 2b3d32a1 2022-12-30 thomas #include "listen.h"
 41 2b3d32a1 2022-12-30 thomas 
 42 2b3d32a1 2022-12-30 thomas #ifndef nitems
 43 2b3d32a1 2022-12-30 thomas #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
 44 2b3d32a1 2022-12-30 thomas #endif
 45 2b3d32a1 2022-12-30 thomas 
 46 2b3d32a1 2022-12-30 thomas struct gotd_listen_client {
 47 2b3d32a1 2022-12-30 thomas 	STAILQ_ENTRY(gotd_listen_client)	 entry;
 48 2b3d32a1 2022-12-30 thomas 	uint32_t			 id;
 49 2b3d32a1 2022-12-30 thomas 	int				 fd;
 50 ba63ab46 2023-01-02 thomas 	uid_t				 euid;
 51 2b3d32a1 2022-12-30 thomas };
 52 2b3d32a1 2022-12-30 thomas STAILQ_HEAD(gotd_listen_clients, gotd_listen_client);
 53 2b3d32a1 2022-12-30 thomas 
 54 2b3d32a1 2022-12-30 thomas static struct gotd_listen_clients gotd_listen_clients[GOTD_CLIENT_TABLE_SIZE];
 55 2b3d32a1 2022-12-30 thomas static SIPHASH_KEY clients_hash_key;
 56 2b3d32a1 2022-12-30 thomas static volatile int listen_client_cnt;
 57 2b3d32a1 2022-12-30 thomas static int inflight;
 58 2b3d32a1 2022-12-30 thomas 
 59 ba63ab46 2023-01-02 thomas struct gotd_uid_connection_counter {
 60 ba63ab46 2023-01-02 thomas 	STAILQ_ENTRY(gotd_uid_connection_counter) entry;
 61 ba63ab46 2023-01-02 thomas 	uid_t euid;
 62 ba63ab46 2023-01-02 thomas 	int nconnections;
 63 ba63ab46 2023-01-02 thomas };
 64 ba63ab46 2023-01-02 thomas STAILQ_HEAD(gotd_client_uids, gotd_uid_connection_counter);
 65 ba63ab46 2023-01-02 thomas static struct gotd_client_uids gotd_client_uids[GOTD_CLIENT_TABLE_SIZE];
 66 ba63ab46 2023-01-02 thomas static SIPHASH_KEY uid_hash_key;
 67 ba63ab46 2023-01-02 thomas 
 68 2b3d32a1 2022-12-30 thomas static struct {
 69 2b3d32a1 2022-12-30 thomas 	pid_t pid;
 70 2b3d32a1 2022-12-30 thomas 	const char *title;
 71 2b3d32a1 2022-12-30 thomas 	int fd;
 72 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev iev;
 73 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev pause;
 74 0781db0e 2023-01-06 thomas 	struct gotd_uid_connection_limit *connection_limits;
 75 0781db0e 2023-01-06 thomas 	size_t nconnection_limits;
 76 2b3d32a1 2022-12-30 thomas } gotd_listen;
 77 2b3d32a1 2022-12-30 thomas 
 78 2b3d32a1 2022-12-30 thomas static int inflight;
 79 2b3d32a1 2022-12-30 thomas 
 80 2b3d32a1 2022-12-30 thomas static void listen_shutdown(void);
 81 2b3d32a1 2022-12-30 thomas 
 82 2b3d32a1 2022-12-30 thomas static void
 83 2b3d32a1 2022-12-30 thomas listen_sighdlr(int sig, short event, void *arg)
 84 2b3d32a1 2022-12-30 thomas {
 85 2b3d32a1 2022-12-30 thomas 	/*
 86 2b3d32a1 2022-12-30 thomas 	 * Normal signal handler rules don't apply because libevent
 87 2b3d32a1 2022-12-30 thomas 	 * decouples for us.
 88 2b3d32a1 2022-12-30 thomas 	 */
 89 2b3d32a1 2022-12-30 thomas 
 90 2b3d32a1 2022-12-30 thomas 	switch (sig) {
 91 2b3d32a1 2022-12-30 thomas 	case SIGHUP:
 92 2b3d32a1 2022-12-30 thomas 		break;
 93 2b3d32a1 2022-12-30 thomas 	case SIGUSR1:
 94 2b3d32a1 2022-12-30 thomas 		break;
 95 2b3d32a1 2022-12-30 thomas 	case SIGTERM:
 96 2b3d32a1 2022-12-30 thomas 	case SIGINT:
 97 2b3d32a1 2022-12-30 thomas 		listen_shutdown();
 98 2b3d32a1 2022-12-30 thomas 		/* NOTREACHED */
 99 2b3d32a1 2022-12-30 thomas 		break;
100 2b3d32a1 2022-12-30 thomas 	default:
101 2b3d32a1 2022-12-30 thomas 		fatalx("unexpected signal");
102 2b3d32a1 2022-12-30 thomas 	}
103 2b3d32a1 2022-12-30 thomas }
104 2b3d32a1 2022-12-30 thomas 
105 2b3d32a1 2022-12-30 thomas static uint64_t
106 2b3d32a1 2022-12-30 thomas client_hash(uint32_t client_id)
107 2b3d32a1 2022-12-30 thomas {
108 2b3d32a1 2022-12-30 thomas 	return SipHash24(&clients_hash_key, &client_id, sizeof(client_id));
109 2b3d32a1 2022-12-30 thomas }
110 2b3d32a1 2022-12-30 thomas 
111 2b3d32a1 2022-12-30 thomas static void
112 2b3d32a1 2022-12-30 thomas add_client(struct gotd_listen_client *client)
113 2b3d32a1 2022-12-30 thomas {
114 2b3d32a1 2022-12-30 thomas 	uint64_t slot = client_hash(client->id) % nitems(gotd_listen_clients);
115 2b3d32a1 2022-12-30 thomas 	STAILQ_INSERT_HEAD(&gotd_listen_clients[slot], client, entry);
116 2b3d32a1 2022-12-30 thomas 	listen_client_cnt++;
117 2b3d32a1 2022-12-30 thomas }
118 2b3d32a1 2022-12-30 thomas 
119 2b3d32a1 2022-12-30 thomas static struct gotd_listen_client *
120 2b3d32a1 2022-12-30 thomas find_client(uint32_t client_id)
121 2b3d32a1 2022-12-30 thomas {
122 2b3d32a1 2022-12-30 thomas 	uint64_t slot;
123 2b3d32a1 2022-12-30 thomas 	struct gotd_listen_client *c;
124 2b3d32a1 2022-12-30 thomas 
125 2b3d32a1 2022-12-30 thomas 	slot = client_hash(client_id) % nitems(gotd_listen_clients);
126 2b3d32a1 2022-12-30 thomas 	STAILQ_FOREACH(c, &gotd_listen_clients[slot], entry) {
127 2b3d32a1 2022-12-30 thomas 		if (c->id == client_id)
128 2b3d32a1 2022-12-30 thomas 			return c;
129 2b3d32a1 2022-12-30 thomas 	}
130 2b3d32a1 2022-12-30 thomas 
131 2b3d32a1 2022-12-30 thomas 	return NULL;
132 2b3d32a1 2022-12-30 thomas }
133 2b3d32a1 2022-12-30 thomas 
134 2b3d32a1 2022-12-30 thomas static uint32_t
135 2b3d32a1 2022-12-30 thomas get_client_id(void)
136 2b3d32a1 2022-12-30 thomas {
137 2b3d32a1 2022-12-30 thomas 	int duplicate = 0;
138 2b3d32a1 2022-12-30 thomas 	uint32_t id;
139 2b3d32a1 2022-12-30 thomas 
140 2b3d32a1 2022-12-30 thomas 	do {
141 2b3d32a1 2022-12-30 thomas 		id = arc4random();
142 2b3d32a1 2022-12-30 thomas 		duplicate = (find_client(id) != NULL);
143 2b3d32a1 2022-12-30 thomas 	} while (duplicate || id == 0);
144 2b3d32a1 2022-12-30 thomas 
145 2b3d32a1 2022-12-30 thomas 	return id;
146 ba63ab46 2023-01-02 thomas }
147 ba63ab46 2023-01-02 thomas 
148 ba63ab46 2023-01-02 thomas static uint64_t
149 ba63ab46 2023-01-02 thomas uid_hash(uid_t euid)
150 ba63ab46 2023-01-02 thomas {
151 ba63ab46 2023-01-02 thomas 	return SipHash24(&uid_hash_key, &euid, sizeof(euid));
152 ba63ab46 2023-01-02 thomas }
153 ba63ab46 2023-01-02 thomas 
154 ba63ab46 2023-01-02 thomas static void
155 ba63ab46 2023-01-02 thomas add_uid_connection_counter(struct gotd_uid_connection_counter *counter)
156 ba63ab46 2023-01-02 thomas {
157 ba63ab46 2023-01-02 thomas 	uint64_t slot = uid_hash(counter->euid) % nitems(gotd_client_uids);
158 ba63ab46 2023-01-02 thomas 	STAILQ_INSERT_HEAD(&gotd_client_uids[slot], counter, entry);
159 ba63ab46 2023-01-02 thomas }
160 ba63ab46 2023-01-02 thomas 
161 ba63ab46 2023-01-02 thomas static void
162 ba63ab46 2023-01-02 thomas remove_uid_connection_counter(struct gotd_uid_connection_counter *counter)
163 ba63ab46 2023-01-02 thomas {
164 ba63ab46 2023-01-02 thomas 	uint64_t slot = uid_hash(counter->euid) % nitems(gotd_client_uids);
165 ba63ab46 2023-01-02 thomas 	STAILQ_REMOVE(&gotd_client_uids[slot], counter,
166 ba63ab46 2023-01-02 thomas 	    gotd_uid_connection_counter, entry);
167 ba63ab46 2023-01-02 thomas }
168 ba63ab46 2023-01-02 thomas 
169 ba63ab46 2023-01-02 thomas static struct gotd_uid_connection_counter *
170 ba63ab46 2023-01-02 thomas find_uid_connection_counter(uid_t euid)
171 ba63ab46 2023-01-02 thomas {
172 ba63ab46 2023-01-02 thomas 	uint64_t slot;
173 ba63ab46 2023-01-02 thomas 	struct gotd_uid_connection_counter *c;
174 ba63ab46 2023-01-02 thomas 
175 ba63ab46 2023-01-02 thomas 	slot = uid_hash(euid) % nitems(gotd_client_uids);
176 ba63ab46 2023-01-02 thomas 	STAILQ_FOREACH(c, &gotd_client_uids[slot], entry) {
177 ba63ab46 2023-01-02 thomas 		if (c->euid == euid)
178 ba63ab46 2023-01-02 thomas 			return c;
179 ba63ab46 2023-01-02 thomas 	}
180 ba63ab46 2023-01-02 thomas 
181 ba63ab46 2023-01-02 thomas 	return NULL;
182 2b3d32a1 2022-12-30 thomas }
183 2b3d32a1 2022-12-30 thomas 
184 2b3d32a1 2022-12-30 thomas static const struct got_error *
185 2b3d32a1 2022-12-30 thomas disconnect(struct gotd_listen_client *client)
186 2b3d32a1 2022-12-30 thomas {
187 ba63ab46 2023-01-02 thomas 	struct gotd_uid_connection_counter *counter;
188 2b3d32a1 2022-12-30 thomas 	uint64_t slot;
189 2b3d32a1 2022-12-30 thomas 	int client_fd;
190 2b3d32a1 2022-12-30 thomas 
191 2b3d32a1 2022-12-30 thomas 	log_debug("client on fd %d disconnecting", client->fd);
192 2b3d32a1 2022-12-30 thomas 
193 2b3d32a1 2022-12-30 thomas 	slot = client_hash(client->id) % nitems(gotd_listen_clients);
194 2b3d32a1 2022-12-30 thomas 	STAILQ_REMOVE(&gotd_listen_clients[slot], client,
195 2b3d32a1 2022-12-30 thomas 	    gotd_listen_client, entry);
196 ba63ab46 2023-01-02 thomas 
197 ba63ab46 2023-01-02 thomas 	counter = find_uid_connection_counter(client->euid);
198 ba63ab46 2023-01-02 thomas 	if (counter) {
199 ba63ab46 2023-01-02 thomas 		if (counter->nconnections > 0)
200 ba63ab46 2023-01-02 thomas 			counter->nconnections--;
201 ba63ab46 2023-01-02 thomas 		if (counter->nconnections == 0) {
202 ba63ab46 2023-01-02 thomas 			remove_uid_connection_counter(counter);
203 ba63ab46 2023-01-02 thomas 			free(counter);
204 ba63ab46 2023-01-02 thomas 		}
205 ba63ab46 2023-01-02 thomas 	}
206 ba63ab46 2023-01-02 thomas 
207 2b3d32a1 2022-12-30 thomas 	client_fd = client->fd;
208 2b3d32a1 2022-12-30 thomas 	free(client);
209 2b3d32a1 2022-12-30 thomas 	inflight--;
210 2b3d32a1 2022-12-30 thomas 	listen_client_cnt--;
211 2b3d32a1 2022-12-30 thomas 	if (close(client_fd) == -1)
212 2b3d32a1 2022-12-30 thomas 		return got_error_from_errno("close");
213 2b3d32a1 2022-12-30 thomas 
214 2b3d32a1 2022-12-30 thomas 	return NULL;
215 2b3d32a1 2022-12-30 thomas }
216 2b3d32a1 2022-12-30 thomas 
217 2b3d32a1 2022-12-30 thomas static int
218 2b3d32a1 2022-12-30 thomas accept_reserve(int fd, struct sockaddr *addr, socklen_t *addrlen,
219 2b3d32a1 2022-12-30 thomas     int reserve, volatile int *counter)
220 2b3d32a1 2022-12-30 thomas {
221 2b3d32a1 2022-12-30 thomas 	int ret;
222 621b8de0 2023-08-23 thomas 	int sock_flags = SOCK_NONBLOCK;
223 2b3d32a1 2022-12-30 thomas 
224 621b8de0 2023-08-23 thomas #ifdef SOCK_CLOEXEC
225 621b8de0 2023-08-23 thomas 	sock_flags |= SOCK_CLOEXEC;
226 621b8de0 2023-08-23 thomas #endif
227 621b8de0 2023-08-23 thomas 
228 2b3d32a1 2022-12-30 thomas 	if (getdtablecount() + reserve +
229 2b3d32a1 2022-12-30 thomas 	    ((*counter + 1) * GOTD_FD_NEEDED) >= getdtablesize()) {
230 2b3d32a1 2022-12-30 thomas 		log_debug("inflight fds exceeded");
231 2b3d32a1 2022-12-30 thomas 		errno = EMFILE;
232 2b3d32a1 2022-12-30 thomas 		return -1;
233 2b3d32a1 2022-12-30 thomas 	}
234 621b8de0 2023-08-23 thomas #ifdef __APPLE__
235 621b8de0 2023-08-23 thomas 	/* TA:  silence warning from GCC. */
236 621b8de0 2023-08-23 thomas 	(void)sock_flags;
237 621b8de0 2023-08-23 thomas 	ret = accept(fd, addr, addrlen);
238 621b8de0 2023-08-23 thomas #else
239 621b8de0 2023-08-23 thomas 	ret = accept4(fd, addr, addrlen, sock_flags);
240 621b8de0 2023-08-23 thomas #endif
241 2b3d32a1 2022-12-30 thomas 
242 621b8de0 2023-08-23 thomas 	if (ret > -1) {
243 2b3d32a1 2022-12-30 thomas 		(*counter)++;
244 2b3d32a1 2022-12-30 thomas 	}
245 2b3d32a1 2022-12-30 thomas 
246 2b3d32a1 2022-12-30 thomas 	return ret;
247 2b3d32a1 2022-12-30 thomas }
248 2b3d32a1 2022-12-30 thomas 
249 2b3d32a1 2022-12-30 thomas static void
250 2b3d32a1 2022-12-30 thomas gotd_accept_paused(int fd, short event, void *arg)
251 2b3d32a1 2022-12-30 thomas {
252 2b3d32a1 2022-12-30 thomas 	event_add(&gotd_listen.iev.ev, NULL);
253 2b3d32a1 2022-12-30 thomas }
254 2b3d32a1 2022-12-30 thomas 
255 2b3d32a1 2022-12-30 thomas static void
256 2b3d32a1 2022-12-30 thomas gotd_accept(int fd, short event, void *arg)
257 2b3d32a1 2022-12-30 thomas {
258 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev *iev = arg;
259 2b3d32a1 2022-12-30 thomas 	struct sockaddr_storage ss;
260 2b3d32a1 2022-12-30 thomas 	struct timeval backoff;
261 2b3d32a1 2022-12-30 thomas 	socklen_t len;
262 2b3d32a1 2022-12-30 thomas 	int s = -1;
263 2b3d32a1 2022-12-30 thomas 	struct gotd_listen_client *client = NULL;
264 ba63ab46 2023-01-02 thomas 	struct gotd_uid_connection_counter *counter = NULL;
265 2b3d32a1 2022-12-30 thomas 	struct gotd_imsg_connect iconn;
266 0bcde4c8 2022-12-30 thomas 	uid_t euid;
267 0bcde4c8 2022-12-30 thomas 	gid_t egid;
268 2b3d32a1 2022-12-30 thomas 
269 2b3d32a1 2022-12-30 thomas 	backoff.tv_sec = 1;
270 2b3d32a1 2022-12-30 thomas 	backoff.tv_usec = 0;
271 2b3d32a1 2022-12-30 thomas 
272 2b3d32a1 2022-12-30 thomas 	if (event_add(&gotd_listen.iev.ev, NULL) == -1) {
273 2b3d32a1 2022-12-30 thomas 		log_warn("event_add");
274 2b3d32a1 2022-12-30 thomas 		return;
275 2b3d32a1 2022-12-30 thomas 	}
276 2b3d32a1 2022-12-30 thomas 	if (event & EV_TIMEOUT)
277 2b3d32a1 2022-12-30 thomas 		return;
278 2b3d32a1 2022-12-30 thomas 
279 2b3d32a1 2022-12-30 thomas 	len = sizeof(ss);
280 2b3d32a1 2022-12-30 thomas 
281 2b3d32a1 2022-12-30 thomas 	/* Other backoff conditions apart from EMFILE/ENFILE? */
282 2b3d32a1 2022-12-30 thomas 	s = accept_reserve(fd, (struct sockaddr *)&ss, &len, GOTD_FD_RESERVE,
283 2b3d32a1 2022-12-30 thomas 	    &inflight);
284 2b3d32a1 2022-12-30 thomas 	if (s == -1) {
285 2b3d32a1 2022-12-30 thomas 		switch (errno) {
286 2b3d32a1 2022-12-30 thomas 		case EINTR:
287 2b3d32a1 2022-12-30 thomas 		case EWOULDBLOCK:
288 2b3d32a1 2022-12-30 thomas 		case ECONNABORTED:
289 2b3d32a1 2022-12-30 thomas 			return;
290 2b3d32a1 2022-12-30 thomas 		case EMFILE:
291 2b3d32a1 2022-12-30 thomas 		case ENFILE:
292 2b3d32a1 2022-12-30 thomas 			event_del(&gotd_listen.iev.ev);
293 2b3d32a1 2022-12-30 thomas 			evtimer_add(&gotd_listen.pause.ev, &backoff);
294 2b3d32a1 2022-12-30 thomas 			return;
295 2b3d32a1 2022-12-30 thomas 		default:
296 2b3d32a1 2022-12-30 thomas 			log_warn("accept");
297 2b3d32a1 2022-12-30 thomas 			return;
298 2b3d32a1 2022-12-30 thomas 		}
299 2b3d32a1 2022-12-30 thomas 	}
300 2b3d32a1 2022-12-30 thomas 
301 2b3d32a1 2022-12-30 thomas 	if (listen_client_cnt >= GOTD_MAXCLIENTS)
302 0bcde4c8 2022-12-30 thomas 		goto err;
303 0bcde4c8 2022-12-30 thomas 
304 0bcde4c8 2022-12-30 thomas 	if (getpeereid(s, &euid, &egid) == -1) {
305 0bcde4c8 2022-12-30 thomas 		log_warn("getpeerid");
306 2b3d32a1 2022-12-30 thomas 		goto err;
307 0bcde4c8 2022-12-30 thomas 	}
308 2b3d32a1 2022-12-30 thomas 
309 ba63ab46 2023-01-02 thomas 	counter = find_uid_connection_counter(euid);
310 ba63ab46 2023-01-02 thomas 	if (counter == NULL) {
311 ba63ab46 2023-01-02 thomas 		counter = calloc(1, sizeof(*counter));
312 ba63ab46 2023-01-02 thomas 		if (counter == NULL) {
313 ba63ab46 2023-01-02 thomas 			log_warn("%s: calloc", __func__);
314 ba63ab46 2023-01-02 thomas 			goto err;
315 ba63ab46 2023-01-02 thomas 		}
316 ba63ab46 2023-01-02 thomas 		counter->euid = euid;
317 ba63ab46 2023-01-02 thomas 		counter->nconnections = 1;
318 ba63ab46 2023-01-02 thomas 		add_uid_connection_counter(counter);
319 ba63ab46 2023-01-02 thomas 	} else {
320 0781db0e 2023-01-06 thomas 		int max_connections = GOTD_MAX_CONN_PER_UID;
321 0781db0e 2023-01-06 thomas 		struct gotd_uid_connection_limit *limit;
322 0781db0e 2023-01-06 thomas 
323 0781db0e 2023-01-06 thomas 		limit = gotd_find_uid_connection_limit(
324 0781db0e 2023-01-06 thomas 		    gotd_listen.connection_limits,
325 0781db0e 2023-01-06 thomas 		    gotd_listen.nconnection_limits, euid);
326 0781db0e 2023-01-06 thomas 		if (limit)
327 0781db0e 2023-01-06 thomas 			max_connections = limit->max_connections;
328 0781db0e 2023-01-06 thomas 
329 0781db0e 2023-01-06 thomas 		if (counter->nconnections >= max_connections) {
330 ba63ab46 2023-01-02 thomas 			log_warnx("maximum connections exceeded for uid %d",
331 ba63ab46 2023-01-02 thomas 			    euid);
332 ba63ab46 2023-01-02 thomas 			goto err;
333 ba63ab46 2023-01-02 thomas 		}
334 ba63ab46 2023-01-02 thomas 		counter->nconnections++;
335 ba63ab46 2023-01-02 thomas 	}
336 ba63ab46 2023-01-02 thomas 
337 2b3d32a1 2022-12-30 thomas 	client = calloc(1, sizeof(*client));
338 2b3d32a1 2022-12-30 thomas 	if (client == NULL) {
339 2b3d32a1 2022-12-30 thomas 		log_warn("%s: calloc", __func__);
340 2b3d32a1 2022-12-30 thomas 		goto err;
341 2b3d32a1 2022-12-30 thomas 	}
342 2b3d32a1 2022-12-30 thomas 	client->id = get_client_id();
343 2b3d32a1 2022-12-30 thomas 	client->fd = s;
344 ba63ab46 2023-01-02 thomas 	client->euid = euid;
345 2b3d32a1 2022-12-30 thomas 	s = -1;
346 2b3d32a1 2022-12-30 thomas 	add_client(client);
347 0bcde4c8 2022-12-30 thomas 	log_debug("%s: new client connected on fd %d uid %d gid %d", __func__,
348 0bcde4c8 2022-12-30 thomas 	    client->fd, euid, egid);
349 2b3d32a1 2022-12-30 thomas 
350 2b3d32a1 2022-12-30 thomas 	memset(&iconn, 0, sizeof(iconn));
351 2b3d32a1 2022-12-30 thomas 	iconn.client_id = client->id;
352 0bcde4c8 2022-12-30 thomas 	iconn.euid = euid;
353 0bcde4c8 2022-12-30 thomas 	iconn.egid = egid;
354 2b3d32a1 2022-12-30 thomas 	s = dup(client->fd);
355 2b3d32a1 2022-12-30 thomas 	if (s == -1) {
356 2b3d32a1 2022-12-30 thomas 		log_warn("%s: dup", __func__);
357 2b3d32a1 2022-12-30 thomas 		goto err;
358 2b3d32a1 2022-12-30 thomas 	}
359 2b3d32a1 2022-12-30 thomas 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_CONNECT, PROC_LISTEN, s,
360 2b3d32a1 2022-12-30 thomas 	    &iconn, sizeof(iconn)) == -1) {
361 2b3d32a1 2022-12-30 thomas 		log_warn("imsg compose CONNECT");
362 2b3d32a1 2022-12-30 thomas 		goto err;
363 2b3d32a1 2022-12-30 thomas 	}
364 2b3d32a1 2022-12-30 thomas 
365 2b3d32a1 2022-12-30 thomas 	return;
366 2b3d32a1 2022-12-30 thomas err:
367 2b3d32a1 2022-12-30 thomas 	inflight--;
368 2b3d32a1 2022-12-30 thomas 	if (client)
369 2b3d32a1 2022-12-30 thomas 		disconnect(client);
370 2b3d32a1 2022-12-30 thomas 	if (s != -1)
371 2b3d32a1 2022-12-30 thomas 		close(s);
372 2b3d32a1 2022-12-30 thomas }
373 2b3d32a1 2022-12-30 thomas 
374 2b3d32a1 2022-12-30 thomas static const struct got_error *
375 2b3d32a1 2022-12-30 thomas recv_disconnect(struct imsg *imsg)
376 2b3d32a1 2022-12-30 thomas {
377 2b3d32a1 2022-12-30 thomas 	struct gotd_imsg_disconnect idisconnect;
378 2b3d32a1 2022-12-30 thomas 	size_t datalen;
379 2b3d32a1 2022-12-30 thomas 	struct gotd_listen_client *client = NULL;
380 2b3d32a1 2022-12-30 thomas 
381 2b3d32a1 2022-12-30 thomas 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
382 2b3d32a1 2022-12-30 thomas 	if (datalen != sizeof(idisconnect))
383 2b3d32a1 2022-12-30 thomas 		return got_error(GOT_ERR_PRIVSEP_LEN);
384 2b3d32a1 2022-12-30 thomas 	memcpy(&idisconnect, imsg->data, sizeof(idisconnect));
385 2b3d32a1 2022-12-30 thomas 
386 2b3d32a1 2022-12-30 thomas 	log_debug("client disconnecting");
387 2b3d32a1 2022-12-30 thomas 
388 2b3d32a1 2022-12-30 thomas 	client = find_client(idisconnect.client_id);
389 2b3d32a1 2022-12-30 thomas 	if (client == NULL)
390 2b3d32a1 2022-12-30 thomas 		return got_error(GOT_ERR_CLIENT_ID);
391 2b3d32a1 2022-12-30 thomas 
392 2b3d32a1 2022-12-30 thomas 	return disconnect(client);
393 2b3d32a1 2022-12-30 thomas }
394 2b3d32a1 2022-12-30 thomas 
395 2b3d32a1 2022-12-30 thomas static void
396 2b3d32a1 2022-12-30 thomas listen_dispatch(int fd, short event, void *arg)
397 2b3d32a1 2022-12-30 thomas {
398 2b3d32a1 2022-12-30 thomas 	const struct got_error *err = NULL;
399 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev *iev = arg;
400 2b3d32a1 2022-12-30 thomas 	struct imsgbuf *ibuf = &iev->ibuf;
401 2b3d32a1 2022-12-30 thomas 	struct imsg imsg;
402 2b3d32a1 2022-12-30 thomas 	ssize_t n;
403 2b3d32a1 2022-12-30 thomas 	int shut = 0;
404 2b3d32a1 2022-12-30 thomas 
405 2b3d32a1 2022-12-30 thomas 	if (event & EV_READ) {
406 2b3d32a1 2022-12-30 thomas 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
407 2b3d32a1 2022-12-30 thomas 			fatal("imsg_read error");
408 2b3d32a1 2022-12-30 thomas 		if (n == 0)	/* Connection closed. */
409 2b3d32a1 2022-12-30 thomas 			shut = 1;
410 2b3d32a1 2022-12-30 thomas 	}
411 2b3d32a1 2022-12-30 thomas 
412 2b3d32a1 2022-12-30 thomas 	if (event & EV_WRITE) {
413 2b3d32a1 2022-12-30 thomas 		n = msgbuf_write(&ibuf->w);
414 2b3d32a1 2022-12-30 thomas 		if (n == -1 && errno != EAGAIN)
415 2b3d32a1 2022-12-30 thomas 			fatal("msgbuf_write");
416 2b3d32a1 2022-12-30 thomas 		if (n == 0)	/* Connection closed. */
417 2b3d32a1 2022-12-30 thomas 			shut = 1;
418 2b3d32a1 2022-12-30 thomas 	}
419 2b3d32a1 2022-12-30 thomas 
420 2b3d32a1 2022-12-30 thomas 	for (;;) {
421 2b3d32a1 2022-12-30 thomas 		if ((n = imsg_get(ibuf, &imsg)) == -1)
422 2b3d32a1 2022-12-30 thomas 			fatal("%s: imsg_get", __func__);
423 2b3d32a1 2022-12-30 thomas 		if (n == 0)	/* No more messages. */
424 2b3d32a1 2022-12-30 thomas 			break;
425 2b3d32a1 2022-12-30 thomas 
426 2b3d32a1 2022-12-30 thomas 		switch (imsg.hdr.type) {
427 2b3d32a1 2022-12-30 thomas 		case GOTD_IMSG_DISCONNECT:
428 2b3d32a1 2022-12-30 thomas 			err = recv_disconnect(&imsg);
429 2b3d32a1 2022-12-30 thomas 			if (err)
430 5330ab76 2023-02-17 thomas 				log_warnx("disconnect: %s", err->msg);
431 2b3d32a1 2022-12-30 thomas 			break;
432 2b3d32a1 2022-12-30 thomas 		default:
433 5330ab76 2023-02-17 thomas 			log_debug("unexpected imsg %d", imsg.hdr.type);
434 2b3d32a1 2022-12-30 thomas 			break;
435 2b3d32a1 2022-12-30 thomas 		}
436 2b3d32a1 2022-12-30 thomas 
437 2b3d32a1 2022-12-30 thomas 		imsg_free(&imsg);
438 2b3d32a1 2022-12-30 thomas 	}
439 2b3d32a1 2022-12-30 thomas 
440 2b3d32a1 2022-12-30 thomas 	if (!shut) {
441 2b3d32a1 2022-12-30 thomas 		gotd_imsg_event_add(iev);
442 2b3d32a1 2022-12-30 thomas 	} else {
443 2b3d32a1 2022-12-30 thomas 		/* This pipe is dead. Remove its event handler */
444 2b3d32a1 2022-12-30 thomas 		event_del(&iev->ev);
445 2b3d32a1 2022-12-30 thomas 		event_loopexit(NULL);
446 2b3d32a1 2022-12-30 thomas 	}
447 2b3d32a1 2022-12-30 thomas }
448 2b3d32a1 2022-12-30 thomas 
449 2b3d32a1 2022-12-30 thomas void
450 0781db0e 2023-01-06 thomas listen_main(const char *title, int gotd_socket,
451 0781db0e 2023-01-06 thomas     struct gotd_uid_connection_limit *connection_limits,
452 0781db0e 2023-01-06 thomas     size_t nconnection_limits)
453 2b3d32a1 2022-12-30 thomas {
454 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev iev;
455 2b3d32a1 2022-12-30 thomas 	struct event evsigint, evsigterm, evsighup, evsigusr1;
456 56409302 2023-01-02 thomas 
457 56409302 2023-01-02 thomas 	arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
458 ba63ab46 2023-01-02 thomas 	arc4random_buf(&uid_hash_key, sizeof(uid_hash_key));
459 2b3d32a1 2022-12-30 thomas 
460 2b3d32a1 2022-12-30 thomas 	gotd_listen.title = title;
461 2b3d32a1 2022-12-30 thomas 	gotd_listen.pid = getpid();
462 2b3d32a1 2022-12-30 thomas 	gotd_listen.fd = gotd_socket;
463 0781db0e 2023-01-06 thomas 	gotd_listen.connection_limits = connection_limits;
464 0781db0e 2023-01-06 thomas 	gotd_listen.nconnection_limits = nconnection_limits;
465 2b3d32a1 2022-12-30 thomas 
466 2b3d32a1 2022-12-30 thomas 	signal_set(&evsigint, SIGINT, listen_sighdlr, NULL);
467 2b3d32a1 2022-12-30 thomas 	signal_set(&evsigterm, SIGTERM, listen_sighdlr, NULL);
468 2b3d32a1 2022-12-30 thomas 	signal_set(&evsighup, SIGHUP, listen_sighdlr, NULL);
469 2b3d32a1 2022-12-30 thomas 	signal_set(&evsigusr1, SIGUSR1, listen_sighdlr, NULL);
470 2b3d32a1 2022-12-30 thomas 	signal(SIGPIPE, SIG_IGN);
471 2b3d32a1 2022-12-30 thomas 
472 2b3d32a1 2022-12-30 thomas 	signal_add(&evsigint, NULL);
473 2b3d32a1 2022-12-30 thomas 	signal_add(&evsigterm, NULL);
474 2b3d32a1 2022-12-30 thomas 	signal_add(&evsighup, NULL);
475 2b3d32a1 2022-12-30 thomas 	signal_add(&evsigusr1, NULL);
476 2b3d32a1 2022-12-30 thomas 
477 2b3d32a1 2022-12-30 thomas 	imsg_init(&iev.ibuf, GOTD_FILENO_MSG_PIPE);
478 2b3d32a1 2022-12-30 thomas 	iev.handler = listen_dispatch;
479 2b3d32a1 2022-12-30 thomas 	iev.events = EV_READ;
480 2b3d32a1 2022-12-30 thomas 	iev.handler_arg = NULL;
481 2b3d32a1 2022-12-30 thomas 	event_set(&iev.ev, iev.ibuf.fd, EV_READ, listen_dispatch, &iev);
482 2b3d32a1 2022-12-30 thomas 	if (event_add(&iev.ev, NULL) == -1)
483 2b3d32a1 2022-12-30 thomas 		fatalx("event add");
484 2b3d32a1 2022-12-30 thomas 
485 2b3d32a1 2022-12-30 thomas 	event_set(&gotd_listen.iev.ev, gotd_listen.fd, EV_READ | EV_PERSIST,
486 2b3d32a1 2022-12-30 thomas 	    gotd_accept, &iev);
487 2b3d32a1 2022-12-30 thomas 	if (event_add(&gotd_listen.iev.ev, NULL))
488 2b3d32a1 2022-12-30 thomas 		fatalx("event add");
489 2b3d32a1 2022-12-30 thomas 	evtimer_set(&gotd_listen.pause.ev, gotd_accept_paused, NULL);
490 2b3d32a1 2022-12-30 thomas 
491 2b3d32a1 2022-12-30 thomas 	event_dispatch();
492 2b3d32a1 2022-12-30 thomas 
493 2b3d32a1 2022-12-30 thomas 	listen_shutdown();
494 2b3d32a1 2022-12-30 thomas }
495 2b3d32a1 2022-12-30 thomas 
496 2b3d32a1 2022-12-30 thomas static void
497 2b3d32a1 2022-12-30 thomas listen_shutdown(void)
498 2b3d32a1 2022-12-30 thomas {
499 5330ab76 2023-02-17 thomas 	log_debug("shutting down");
500 2b3d32a1 2022-12-30 thomas 
501 0781db0e 2023-01-06 thomas 	free(gotd_listen.connection_limits);
502 2b3d32a1 2022-12-30 thomas 	if (gotd_listen.fd != -1)
503 2b3d32a1 2022-12-30 thomas 		close(gotd_listen.fd);
504 2b3d32a1 2022-12-30 thomas 
505 2b3d32a1 2022-12-30 thomas 	exit(0);
506 2b3d32a1 2022-12-30 thomas }