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 <siphash.h>
 25 2b3d32a1 2022-12-30 thomas #include <stdint.h>
 26 2b3d32a1 2022-12-30 thomas #include <stdio.h>
 27 2b3d32a1 2022-12-30 thomas #include <stdlib.h>
 28 2b3d32a1 2022-12-30 thomas #include <string.h>
 29 2b3d32a1 2022-12-30 thomas #include <imsg.h>
 30 2b3d32a1 2022-12-30 thomas #include <limits.h>
 31 2b3d32a1 2022-12-30 thomas #include <sha1.h>
 32 2b3d32a1 2022-12-30 thomas #include <signal.h>
 33 2b3d32a1 2022-12-30 thomas #include <unistd.h>
 34 2b3d32a1 2022-12-30 thomas 
 35 2b3d32a1 2022-12-30 thomas #include "got_error.h"
 36 2b3d32a1 2022-12-30 thomas 
 37 2b3d32a1 2022-12-30 thomas #include "gotd.h"
 38 2b3d32a1 2022-12-30 thomas #include "log.h"
 39 2b3d32a1 2022-12-30 thomas #include "listen.h"
 40 2b3d32a1 2022-12-30 thomas 
 41 2b3d32a1 2022-12-30 thomas #ifndef nitems
 42 2b3d32a1 2022-12-30 thomas #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
 43 2b3d32a1 2022-12-30 thomas #endif
 44 2b3d32a1 2022-12-30 thomas 
 45 2b3d32a1 2022-12-30 thomas struct gotd_listen_client {
 46 2b3d32a1 2022-12-30 thomas 	STAILQ_ENTRY(gotd_listen_client)	 entry;
 47 2b3d32a1 2022-12-30 thomas 	uint32_t			 id;
 48 2b3d32a1 2022-12-30 thomas 	int				 fd;
 49 ba63ab46 2023-01-02 thomas 	uid_t				 euid;
 50 2b3d32a1 2022-12-30 thomas };
 51 2b3d32a1 2022-12-30 thomas STAILQ_HEAD(gotd_listen_clients, gotd_listen_client);
 52 2b3d32a1 2022-12-30 thomas 
 53 2b3d32a1 2022-12-30 thomas static struct gotd_listen_clients gotd_listen_clients[GOTD_CLIENT_TABLE_SIZE];
 54 2b3d32a1 2022-12-30 thomas static SIPHASH_KEY clients_hash_key;
 55 2b3d32a1 2022-12-30 thomas static volatile int listen_client_cnt;
 56 2b3d32a1 2022-12-30 thomas static int inflight;
 57 2b3d32a1 2022-12-30 thomas 
 58 ba63ab46 2023-01-02 thomas struct gotd_uid_connection_counter {
 59 ba63ab46 2023-01-02 thomas 	STAILQ_ENTRY(gotd_uid_connection_counter) entry;
 60 ba63ab46 2023-01-02 thomas 	uid_t euid;
 61 ba63ab46 2023-01-02 thomas 	int nconnections;
 62 ba63ab46 2023-01-02 thomas };
 63 ba63ab46 2023-01-02 thomas STAILQ_HEAD(gotd_client_uids, gotd_uid_connection_counter);
 64 ba63ab46 2023-01-02 thomas static struct gotd_client_uids gotd_client_uids[GOTD_CLIENT_TABLE_SIZE];
 65 ba63ab46 2023-01-02 thomas static SIPHASH_KEY uid_hash_key;
 66 ba63ab46 2023-01-02 thomas 
 67 2b3d32a1 2022-12-30 thomas static struct {
 68 2b3d32a1 2022-12-30 thomas 	pid_t pid;
 69 2b3d32a1 2022-12-30 thomas 	const char *title;
 70 2b3d32a1 2022-12-30 thomas 	int fd;
 71 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev iev;
 72 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev pause;
 73 0781db0e 2023-01-06 thomas 	struct gotd_uid_connection_limit *connection_limits;
 74 0781db0e 2023-01-06 thomas 	size_t nconnection_limits;
 75 2b3d32a1 2022-12-30 thomas } gotd_listen;
 76 2b3d32a1 2022-12-30 thomas 
 77 2b3d32a1 2022-12-30 thomas static int inflight;
 78 2b3d32a1 2022-12-30 thomas 
 79 2b3d32a1 2022-12-30 thomas static void listen_shutdown(void);
 80 2b3d32a1 2022-12-30 thomas 
 81 2b3d32a1 2022-12-30 thomas static void
 82 2b3d32a1 2022-12-30 thomas listen_sighdlr(int sig, short event, void *arg)
 83 2b3d32a1 2022-12-30 thomas {
 84 2b3d32a1 2022-12-30 thomas 	/*
 85 2b3d32a1 2022-12-30 thomas 	 * Normal signal handler rules don't apply because libevent
 86 2b3d32a1 2022-12-30 thomas 	 * decouples for us.
 87 2b3d32a1 2022-12-30 thomas 	 */
 88 2b3d32a1 2022-12-30 thomas 
 89 2b3d32a1 2022-12-30 thomas 	switch (sig) {
 90 2b3d32a1 2022-12-30 thomas 	case SIGHUP:
 91 2b3d32a1 2022-12-30 thomas 		break;
 92 2b3d32a1 2022-12-30 thomas 	case SIGUSR1:
 93 2b3d32a1 2022-12-30 thomas 		break;
 94 2b3d32a1 2022-12-30 thomas 	case SIGTERM:
 95 2b3d32a1 2022-12-30 thomas 	case SIGINT:
 96 2b3d32a1 2022-12-30 thomas 		listen_shutdown();
 97 2b3d32a1 2022-12-30 thomas 		/* NOTREACHED */
 98 2b3d32a1 2022-12-30 thomas 		break;
 99 2b3d32a1 2022-12-30 thomas 	default:
100 2b3d32a1 2022-12-30 thomas 		fatalx("unexpected signal");
101 2b3d32a1 2022-12-30 thomas 	}
102 2b3d32a1 2022-12-30 thomas }
103 2b3d32a1 2022-12-30 thomas 
104 2b3d32a1 2022-12-30 thomas static uint64_t
105 2b3d32a1 2022-12-30 thomas client_hash(uint32_t client_id)
106 2b3d32a1 2022-12-30 thomas {
107 2b3d32a1 2022-12-30 thomas 	return SipHash24(&clients_hash_key, &client_id, sizeof(client_id));
108 2b3d32a1 2022-12-30 thomas }
109 2b3d32a1 2022-12-30 thomas 
110 2b3d32a1 2022-12-30 thomas static void
111 2b3d32a1 2022-12-30 thomas add_client(struct gotd_listen_client *client)
112 2b3d32a1 2022-12-30 thomas {
113 2b3d32a1 2022-12-30 thomas 	uint64_t slot = client_hash(client->id) % nitems(gotd_listen_clients);
114 2b3d32a1 2022-12-30 thomas 	STAILQ_INSERT_HEAD(&gotd_listen_clients[slot], client, entry);
115 2b3d32a1 2022-12-30 thomas 	listen_client_cnt++;
116 2b3d32a1 2022-12-30 thomas }
117 2b3d32a1 2022-12-30 thomas 
118 2b3d32a1 2022-12-30 thomas static struct gotd_listen_client *
119 2b3d32a1 2022-12-30 thomas find_client(uint32_t client_id)
120 2b3d32a1 2022-12-30 thomas {
121 2b3d32a1 2022-12-30 thomas 	uint64_t slot;
122 2b3d32a1 2022-12-30 thomas 	struct gotd_listen_client *c;
123 2b3d32a1 2022-12-30 thomas 
124 2b3d32a1 2022-12-30 thomas 	slot = client_hash(client_id) % nitems(gotd_listen_clients);
125 2b3d32a1 2022-12-30 thomas 	STAILQ_FOREACH(c, &gotd_listen_clients[slot], entry) {
126 2b3d32a1 2022-12-30 thomas 		if (c->id == client_id)
127 2b3d32a1 2022-12-30 thomas 			return c;
128 2b3d32a1 2022-12-30 thomas 	}
129 2b3d32a1 2022-12-30 thomas 
130 2b3d32a1 2022-12-30 thomas 	return NULL;
131 2b3d32a1 2022-12-30 thomas }
132 2b3d32a1 2022-12-30 thomas 
133 2b3d32a1 2022-12-30 thomas static uint32_t
134 2b3d32a1 2022-12-30 thomas get_client_id(void)
135 2b3d32a1 2022-12-30 thomas {
136 2b3d32a1 2022-12-30 thomas 	int duplicate = 0;
137 2b3d32a1 2022-12-30 thomas 	uint32_t id;
138 2b3d32a1 2022-12-30 thomas 
139 2b3d32a1 2022-12-30 thomas 	do {
140 2b3d32a1 2022-12-30 thomas 		id = arc4random();
141 2b3d32a1 2022-12-30 thomas 		duplicate = (find_client(id) != NULL);
142 2b3d32a1 2022-12-30 thomas 	} while (duplicate || id == 0);
143 2b3d32a1 2022-12-30 thomas 
144 2b3d32a1 2022-12-30 thomas 	return id;
145 ba63ab46 2023-01-02 thomas }
146 ba63ab46 2023-01-02 thomas 
147 ba63ab46 2023-01-02 thomas static uint64_t
148 ba63ab46 2023-01-02 thomas uid_hash(uid_t euid)
149 ba63ab46 2023-01-02 thomas {
150 ba63ab46 2023-01-02 thomas 	return SipHash24(&uid_hash_key, &euid, sizeof(euid));
151 ba63ab46 2023-01-02 thomas }
152 ba63ab46 2023-01-02 thomas 
153 ba63ab46 2023-01-02 thomas static void
154 ba63ab46 2023-01-02 thomas add_uid_connection_counter(struct gotd_uid_connection_counter *counter)
155 ba63ab46 2023-01-02 thomas {
156 ba63ab46 2023-01-02 thomas 	uint64_t slot = uid_hash(counter->euid) % nitems(gotd_client_uids);
157 ba63ab46 2023-01-02 thomas 	STAILQ_INSERT_HEAD(&gotd_client_uids[slot], counter, entry);
158 ba63ab46 2023-01-02 thomas }
159 ba63ab46 2023-01-02 thomas 
160 ba63ab46 2023-01-02 thomas static void
161 ba63ab46 2023-01-02 thomas remove_uid_connection_counter(struct gotd_uid_connection_counter *counter)
162 ba63ab46 2023-01-02 thomas {
163 ba63ab46 2023-01-02 thomas 	uint64_t slot = uid_hash(counter->euid) % nitems(gotd_client_uids);
164 ba63ab46 2023-01-02 thomas 	STAILQ_REMOVE(&gotd_client_uids[slot], counter,
165 ba63ab46 2023-01-02 thomas 	    gotd_uid_connection_counter, entry);
166 ba63ab46 2023-01-02 thomas }
167 ba63ab46 2023-01-02 thomas 
168 ba63ab46 2023-01-02 thomas static struct gotd_uid_connection_counter *
169 ba63ab46 2023-01-02 thomas find_uid_connection_counter(uid_t euid)
170 ba63ab46 2023-01-02 thomas {
171 ba63ab46 2023-01-02 thomas 	uint64_t slot;
172 ba63ab46 2023-01-02 thomas 	struct gotd_uid_connection_counter *c;
173 ba63ab46 2023-01-02 thomas 
174 ba63ab46 2023-01-02 thomas 	slot = uid_hash(euid) % nitems(gotd_client_uids);
175 ba63ab46 2023-01-02 thomas 	STAILQ_FOREACH(c, &gotd_client_uids[slot], entry) {
176 ba63ab46 2023-01-02 thomas 		if (c->euid == euid)
177 ba63ab46 2023-01-02 thomas 			return c;
178 0781db0e 2023-01-06 thomas 	}
179 0781db0e 2023-01-06 thomas 
180 0781db0e 2023-01-06 thomas 	return NULL;
181 0781db0e 2023-01-06 thomas }
182 0781db0e 2023-01-06 thomas 
183 0781db0e 2023-01-06 thomas struct gotd_uid_connection_limit *
184 0781db0e 2023-01-06 thomas gotd_find_uid_connection_limit(struct gotd_uid_connection_limit *limits,
185 0781db0e 2023-01-06 thomas     size_t nlimits, uid_t uid)
186 0781db0e 2023-01-06 thomas {
187 0781db0e 2023-01-06 thomas 	/* This array is always sorted to allow for binary search. */
188 0781db0e 2023-01-06 thomas 	int i, left = 0, right = nlimits - 1;
189 0781db0e 2023-01-06 thomas 
190 0781db0e 2023-01-06 thomas 	while (left <= right) {
191 0781db0e 2023-01-06 thomas 		i = ((left + right) / 2);
192 0781db0e 2023-01-06 thomas 		if (limits[i].uid == uid)
193 0781db0e 2023-01-06 thomas 			return &limits[i];
194 0781db0e 2023-01-06 thomas 		if (limits[i].uid > uid)
195 0781db0e 2023-01-06 thomas 			left = i + 1;
196 0781db0e 2023-01-06 thomas 		else
197 0781db0e 2023-01-06 thomas 			right = i - 1;
198 ba63ab46 2023-01-02 thomas 	}
199 ba63ab46 2023-01-02 thomas 
200 ba63ab46 2023-01-02 thomas 	return NULL;
201 2b3d32a1 2022-12-30 thomas }
202 2b3d32a1 2022-12-30 thomas 
203 2b3d32a1 2022-12-30 thomas static const struct got_error *
204 2b3d32a1 2022-12-30 thomas disconnect(struct gotd_listen_client *client)
205 2b3d32a1 2022-12-30 thomas {
206 ba63ab46 2023-01-02 thomas 	struct gotd_uid_connection_counter *counter;
207 2b3d32a1 2022-12-30 thomas 	uint64_t slot;
208 2b3d32a1 2022-12-30 thomas 	int client_fd;
209 2b3d32a1 2022-12-30 thomas 
210 2b3d32a1 2022-12-30 thomas 	log_debug("client on fd %d disconnecting", client->fd);
211 2b3d32a1 2022-12-30 thomas 
212 2b3d32a1 2022-12-30 thomas 	slot = client_hash(client->id) % nitems(gotd_listen_clients);
213 2b3d32a1 2022-12-30 thomas 	STAILQ_REMOVE(&gotd_listen_clients[slot], client,
214 2b3d32a1 2022-12-30 thomas 	    gotd_listen_client, entry);
215 ba63ab46 2023-01-02 thomas 
216 ba63ab46 2023-01-02 thomas 	counter = find_uid_connection_counter(client->euid);
217 ba63ab46 2023-01-02 thomas 	if (counter) {
218 ba63ab46 2023-01-02 thomas 		if (counter->nconnections > 0)
219 ba63ab46 2023-01-02 thomas 			counter->nconnections--;
220 ba63ab46 2023-01-02 thomas 		if (counter->nconnections == 0) {
221 ba63ab46 2023-01-02 thomas 			remove_uid_connection_counter(counter);
222 ba63ab46 2023-01-02 thomas 			free(counter);
223 ba63ab46 2023-01-02 thomas 		}
224 ba63ab46 2023-01-02 thomas 	}
225 ba63ab46 2023-01-02 thomas 
226 2b3d32a1 2022-12-30 thomas 	client_fd = client->fd;
227 2b3d32a1 2022-12-30 thomas 	free(client);
228 2b3d32a1 2022-12-30 thomas 	inflight--;
229 2b3d32a1 2022-12-30 thomas 	listen_client_cnt--;
230 2b3d32a1 2022-12-30 thomas 	if (close(client_fd) == -1)
231 2b3d32a1 2022-12-30 thomas 		return got_error_from_errno("close");
232 2b3d32a1 2022-12-30 thomas 
233 2b3d32a1 2022-12-30 thomas 	return NULL;
234 2b3d32a1 2022-12-30 thomas }
235 2b3d32a1 2022-12-30 thomas 
236 2b3d32a1 2022-12-30 thomas static int
237 2b3d32a1 2022-12-30 thomas accept_reserve(int fd, struct sockaddr *addr, socklen_t *addrlen,
238 2b3d32a1 2022-12-30 thomas     int reserve, volatile int *counter)
239 2b3d32a1 2022-12-30 thomas {
240 2b3d32a1 2022-12-30 thomas 	int ret;
241 2b3d32a1 2022-12-30 thomas 
242 2b3d32a1 2022-12-30 thomas 	if (getdtablecount() + reserve +
243 2b3d32a1 2022-12-30 thomas 	    ((*counter + 1) * GOTD_FD_NEEDED) >= getdtablesize()) {
244 2b3d32a1 2022-12-30 thomas 		log_debug("inflight fds exceeded");
245 2b3d32a1 2022-12-30 thomas 		errno = EMFILE;
246 2b3d32a1 2022-12-30 thomas 		return -1;
247 2b3d32a1 2022-12-30 thomas 	}
248 2b3d32a1 2022-12-30 thomas 
249 2b3d32a1 2022-12-30 thomas 	if ((ret = accept4(fd, addr, addrlen,
250 2b3d32a1 2022-12-30 thomas 	    SOCK_NONBLOCK | SOCK_CLOEXEC)) > -1) {
251 2b3d32a1 2022-12-30 thomas 		(*counter)++;
252 2b3d32a1 2022-12-30 thomas 	}
253 2b3d32a1 2022-12-30 thomas 
254 2b3d32a1 2022-12-30 thomas 	return ret;
255 2b3d32a1 2022-12-30 thomas }
256 2b3d32a1 2022-12-30 thomas 
257 2b3d32a1 2022-12-30 thomas static void
258 2b3d32a1 2022-12-30 thomas gotd_accept_paused(int fd, short event, void *arg)
259 2b3d32a1 2022-12-30 thomas {
260 2b3d32a1 2022-12-30 thomas 	event_add(&gotd_listen.iev.ev, NULL);
261 2b3d32a1 2022-12-30 thomas }
262 2b3d32a1 2022-12-30 thomas 
263 2b3d32a1 2022-12-30 thomas static void
264 2b3d32a1 2022-12-30 thomas gotd_accept(int fd, short event, void *arg)
265 2b3d32a1 2022-12-30 thomas {
266 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev *iev = arg;
267 2b3d32a1 2022-12-30 thomas 	struct sockaddr_storage ss;
268 2b3d32a1 2022-12-30 thomas 	struct timeval backoff;
269 2b3d32a1 2022-12-30 thomas 	socklen_t len;
270 2b3d32a1 2022-12-30 thomas 	int s = -1;
271 2b3d32a1 2022-12-30 thomas 	struct gotd_listen_client *client = NULL;
272 ba63ab46 2023-01-02 thomas 	struct gotd_uid_connection_counter *counter = NULL;
273 2b3d32a1 2022-12-30 thomas 	struct gotd_imsg_connect iconn;
274 0bcde4c8 2022-12-30 thomas 	uid_t euid;
275 0bcde4c8 2022-12-30 thomas 	gid_t egid;
276 2b3d32a1 2022-12-30 thomas 
277 2b3d32a1 2022-12-30 thomas 	backoff.tv_sec = 1;
278 2b3d32a1 2022-12-30 thomas 	backoff.tv_usec = 0;
279 2b3d32a1 2022-12-30 thomas 
280 2b3d32a1 2022-12-30 thomas 	if (event_add(&gotd_listen.iev.ev, NULL) == -1) {
281 2b3d32a1 2022-12-30 thomas 		log_warn("event_add");
282 2b3d32a1 2022-12-30 thomas 		return;
283 2b3d32a1 2022-12-30 thomas 	}
284 2b3d32a1 2022-12-30 thomas 	if (event & EV_TIMEOUT)
285 2b3d32a1 2022-12-30 thomas 		return;
286 2b3d32a1 2022-12-30 thomas 
287 2b3d32a1 2022-12-30 thomas 	len = sizeof(ss);
288 2b3d32a1 2022-12-30 thomas 
289 2b3d32a1 2022-12-30 thomas 	/* Other backoff conditions apart from EMFILE/ENFILE? */
290 2b3d32a1 2022-12-30 thomas 	s = accept_reserve(fd, (struct sockaddr *)&ss, &len, GOTD_FD_RESERVE,
291 2b3d32a1 2022-12-30 thomas 	    &inflight);
292 2b3d32a1 2022-12-30 thomas 	if (s == -1) {
293 2b3d32a1 2022-12-30 thomas 		switch (errno) {
294 2b3d32a1 2022-12-30 thomas 		case EINTR:
295 2b3d32a1 2022-12-30 thomas 		case EWOULDBLOCK:
296 2b3d32a1 2022-12-30 thomas 		case ECONNABORTED:
297 2b3d32a1 2022-12-30 thomas 			return;
298 2b3d32a1 2022-12-30 thomas 		case EMFILE:
299 2b3d32a1 2022-12-30 thomas 		case ENFILE:
300 2b3d32a1 2022-12-30 thomas 			event_del(&gotd_listen.iev.ev);
301 2b3d32a1 2022-12-30 thomas 			evtimer_add(&gotd_listen.pause.ev, &backoff);
302 2b3d32a1 2022-12-30 thomas 			return;
303 2b3d32a1 2022-12-30 thomas 		default:
304 2b3d32a1 2022-12-30 thomas 			log_warn("accept");
305 2b3d32a1 2022-12-30 thomas 			return;
306 2b3d32a1 2022-12-30 thomas 		}
307 2b3d32a1 2022-12-30 thomas 	}
308 2b3d32a1 2022-12-30 thomas 
309 2b3d32a1 2022-12-30 thomas 	if (listen_client_cnt >= GOTD_MAXCLIENTS)
310 0bcde4c8 2022-12-30 thomas 		goto err;
311 0bcde4c8 2022-12-30 thomas 
312 0bcde4c8 2022-12-30 thomas 	if (getpeereid(s, &euid, &egid) == -1) {
313 0bcde4c8 2022-12-30 thomas 		log_warn("getpeerid");
314 2b3d32a1 2022-12-30 thomas 		goto err;
315 0bcde4c8 2022-12-30 thomas 	}
316 2b3d32a1 2022-12-30 thomas 
317 ba63ab46 2023-01-02 thomas 	counter = find_uid_connection_counter(euid);
318 ba63ab46 2023-01-02 thomas 	if (counter == NULL) {
319 ba63ab46 2023-01-02 thomas 		counter = calloc(1, sizeof(*counter));
320 ba63ab46 2023-01-02 thomas 		if (counter == NULL) {
321 ba63ab46 2023-01-02 thomas 			log_warn("%s: calloc", __func__);
322 ba63ab46 2023-01-02 thomas 			goto err;
323 ba63ab46 2023-01-02 thomas 		}
324 ba63ab46 2023-01-02 thomas 		counter->euid = euid;
325 ba63ab46 2023-01-02 thomas 		counter->nconnections = 1;
326 ba63ab46 2023-01-02 thomas 		add_uid_connection_counter(counter);
327 ba63ab46 2023-01-02 thomas 	} else {
328 0781db0e 2023-01-06 thomas 		int max_connections = GOTD_MAX_CONN_PER_UID;
329 0781db0e 2023-01-06 thomas 		struct gotd_uid_connection_limit *limit;
330 0781db0e 2023-01-06 thomas 
331 0781db0e 2023-01-06 thomas 		limit = gotd_find_uid_connection_limit(
332 0781db0e 2023-01-06 thomas 		    gotd_listen.connection_limits,
333 0781db0e 2023-01-06 thomas 		    gotd_listen.nconnection_limits, euid);
334 0781db0e 2023-01-06 thomas 		if (limit)
335 0781db0e 2023-01-06 thomas 			max_connections = limit->max_connections;
336 0781db0e 2023-01-06 thomas 
337 0781db0e 2023-01-06 thomas 		if (counter->nconnections >= max_connections) {
338 ba63ab46 2023-01-02 thomas 			log_warnx("maximum connections exceeded for uid %d",
339 ba63ab46 2023-01-02 thomas 			    euid);
340 ba63ab46 2023-01-02 thomas 			goto err;
341 ba63ab46 2023-01-02 thomas 		}
342 ba63ab46 2023-01-02 thomas 		counter->nconnections++;
343 ba63ab46 2023-01-02 thomas 	}
344 ba63ab46 2023-01-02 thomas 
345 2b3d32a1 2022-12-30 thomas 	client = calloc(1, sizeof(*client));
346 2b3d32a1 2022-12-30 thomas 	if (client == NULL) {
347 2b3d32a1 2022-12-30 thomas 		log_warn("%s: calloc", __func__);
348 2b3d32a1 2022-12-30 thomas 		goto err;
349 2b3d32a1 2022-12-30 thomas 	}
350 2b3d32a1 2022-12-30 thomas 	client->id = get_client_id();
351 2b3d32a1 2022-12-30 thomas 	client->fd = s;
352 ba63ab46 2023-01-02 thomas 	client->euid = euid;
353 2b3d32a1 2022-12-30 thomas 	s = -1;
354 2b3d32a1 2022-12-30 thomas 	add_client(client);
355 0bcde4c8 2022-12-30 thomas 	log_debug("%s: new client connected on fd %d uid %d gid %d", __func__,
356 0bcde4c8 2022-12-30 thomas 	    client->fd, euid, egid);
357 2b3d32a1 2022-12-30 thomas 
358 2b3d32a1 2022-12-30 thomas 	memset(&iconn, 0, sizeof(iconn));
359 2b3d32a1 2022-12-30 thomas 	iconn.client_id = client->id;
360 0bcde4c8 2022-12-30 thomas 	iconn.euid = euid;
361 0bcde4c8 2022-12-30 thomas 	iconn.egid = egid;
362 2b3d32a1 2022-12-30 thomas 	s = dup(client->fd);
363 2b3d32a1 2022-12-30 thomas 	if (s == -1) {
364 2b3d32a1 2022-12-30 thomas 		log_warn("%s: dup", __func__);
365 2b3d32a1 2022-12-30 thomas 		goto err;
366 2b3d32a1 2022-12-30 thomas 	}
367 2b3d32a1 2022-12-30 thomas 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_CONNECT, PROC_LISTEN, s,
368 2b3d32a1 2022-12-30 thomas 	    &iconn, sizeof(iconn)) == -1) {
369 2b3d32a1 2022-12-30 thomas 		log_warn("imsg compose CONNECT");
370 2b3d32a1 2022-12-30 thomas 		goto err;
371 2b3d32a1 2022-12-30 thomas 	}
372 2b3d32a1 2022-12-30 thomas 
373 2b3d32a1 2022-12-30 thomas 	return;
374 2b3d32a1 2022-12-30 thomas err:
375 2b3d32a1 2022-12-30 thomas 	inflight--;
376 2b3d32a1 2022-12-30 thomas 	if (client)
377 2b3d32a1 2022-12-30 thomas 		disconnect(client);
378 2b3d32a1 2022-12-30 thomas 	if (s != -1)
379 2b3d32a1 2022-12-30 thomas 		close(s);
380 2b3d32a1 2022-12-30 thomas }
381 2b3d32a1 2022-12-30 thomas 
382 2b3d32a1 2022-12-30 thomas static const struct got_error *
383 2b3d32a1 2022-12-30 thomas recv_disconnect(struct imsg *imsg)
384 2b3d32a1 2022-12-30 thomas {
385 2b3d32a1 2022-12-30 thomas 	struct gotd_imsg_disconnect idisconnect;
386 2b3d32a1 2022-12-30 thomas 	size_t datalen;
387 2b3d32a1 2022-12-30 thomas 	struct gotd_listen_client *client = NULL;
388 2b3d32a1 2022-12-30 thomas 
389 2b3d32a1 2022-12-30 thomas 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
390 2b3d32a1 2022-12-30 thomas 	if (datalen != sizeof(idisconnect))
391 2b3d32a1 2022-12-30 thomas 		return got_error(GOT_ERR_PRIVSEP_LEN);
392 2b3d32a1 2022-12-30 thomas 	memcpy(&idisconnect, imsg->data, sizeof(idisconnect));
393 2b3d32a1 2022-12-30 thomas 
394 2b3d32a1 2022-12-30 thomas 	log_debug("client disconnecting");
395 2b3d32a1 2022-12-30 thomas 
396 2b3d32a1 2022-12-30 thomas 	client = find_client(idisconnect.client_id);
397 2b3d32a1 2022-12-30 thomas 	if (client == NULL)
398 2b3d32a1 2022-12-30 thomas 		return got_error(GOT_ERR_CLIENT_ID);
399 2b3d32a1 2022-12-30 thomas 
400 2b3d32a1 2022-12-30 thomas 	return disconnect(client);
401 2b3d32a1 2022-12-30 thomas }
402 2b3d32a1 2022-12-30 thomas 
403 2b3d32a1 2022-12-30 thomas static void
404 2b3d32a1 2022-12-30 thomas listen_dispatch(int fd, short event, void *arg)
405 2b3d32a1 2022-12-30 thomas {
406 2b3d32a1 2022-12-30 thomas 	const struct got_error *err = NULL;
407 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev *iev = arg;
408 2b3d32a1 2022-12-30 thomas 	struct imsgbuf *ibuf = &iev->ibuf;
409 2b3d32a1 2022-12-30 thomas 	struct imsg imsg;
410 2b3d32a1 2022-12-30 thomas 	ssize_t n;
411 2b3d32a1 2022-12-30 thomas 	int shut = 0;
412 2b3d32a1 2022-12-30 thomas 
413 2b3d32a1 2022-12-30 thomas 	if (event & EV_READ) {
414 2b3d32a1 2022-12-30 thomas 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
415 2b3d32a1 2022-12-30 thomas 			fatal("imsg_read error");
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 	if (event & EV_WRITE) {
421 2b3d32a1 2022-12-30 thomas 		n = msgbuf_write(&ibuf->w);
422 2b3d32a1 2022-12-30 thomas 		if (n == -1 && errno != EAGAIN)
423 2b3d32a1 2022-12-30 thomas 			fatal("msgbuf_write");
424 2b3d32a1 2022-12-30 thomas 		if (n == 0)	/* Connection closed. */
425 2b3d32a1 2022-12-30 thomas 			shut = 1;
426 2b3d32a1 2022-12-30 thomas 	}
427 2b3d32a1 2022-12-30 thomas 
428 2b3d32a1 2022-12-30 thomas 	for (;;) {
429 2b3d32a1 2022-12-30 thomas 		if ((n = imsg_get(ibuf, &imsg)) == -1)
430 2b3d32a1 2022-12-30 thomas 			fatal("%s: imsg_get", __func__);
431 2b3d32a1 2022-12-30 thomas 		if (n == 0)	/* No more messages. */
432 2b3d32a1 2022-12-30 thomas 			break;
433 2b3d32a1 2022-12-30 thomas 
434 2b3d32a1 2022-12-30 thomas 		switch (imsg.hdr.type) {
435 2b3d32a1 2022-12-30 thomas 		case GOTD_IMSG_DISCONNECT:
436 2b3d32a1 2022-12-30 thomas 			err = recv_disconnect(&imsg);
437 2b3d32a1 2022-12-30 thomas 			if (err)
438 2b3d32a1 2022-12-30 thomas 				log_warnx("%s: disconnect: %s",
439 2b3d32a1 2022-12-30 thomas 				    gotd_listen.title, err->msg);
440 2b3d32a1 2022-12-30 thomas 			break;
441 2b3d32a1 2022-12-30 thomas 		default:
442 2b3d32a1 2022-12-30 thomas 			log_debug("%s: unexpected imsg %d", gotd_listen.title,
443 2b3d32a1 2022-12-30 thomas 			    imsg.hdr.type);
444 2b3d32a1 2022-12-30 thomas 			break;
445 2b3d32a1 2022-12-30 thomas 		}
446 2b3d32a1 2022-12-30 thomas 
447 2b3d32a1 2022-12-30 thomas 		imsg_free(&imsg);
448 2b3d32a1 2022-12-30 thomas 	}
449 2b3d32a1 2022-12-30 thomas 
450 2b3d32a1 2022-12-30 thomas 	if (!shut) {
451 2b3d32a1 2022-12-30 thomas 		gotd_imsg_event_add(iev);
452 2b3d32a1 2022-12-30 thomas 	} else {
453 2b3d32a1 2022-12-30 thomas 		/* This pipe is dead. Remove its event handler */
454 2b3d32a1 2022-12-30 thomas 		event_del(&iev->ev);
455 2b3d32a1 2022-12-30 thomas 		event_loopexit(NULL);
456 2b3d32a1 2022-12-30 thomas 	}
457 2b3d32a1 2022-12-30 thomas }
458 2b3d32a1 2022-12-30 thomas 
459 2b3d32a1 2022-12-30 thomas void
460 0781db0e 2023-01-06 thomas listen_main(const char *title, int gotd_socket,
461 0781db0e 2023-01-06 thomas     struct gotd_uid_connection_limit *connection_limits,
462 0781db0e 2023-01-06 thomas     size_t nconnection_limits)
463 2b3d32a1 2022-12-30 thomas {
464 2b3d32a1 2022-12-30 thomas 	struct gotd_imsgev iev;
465 2b3d32a1 2022-12-30 thomas 	struct event evsigint, evsigterm, evsighup, evsigusr1;
466 56409302 2023-01-02 thomas 
467 56409302 2023-01-02 thomas 	arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
468 ba63ab46 2023-01-02 thomas 	arc4random_buf(&uid_hash_key, sizeof(uid_hash_key));
469 2b3d32a1 2022-12-30 thomas 
470 2b3d32a1 2022-12-30 thomas 	gotd_listen.title = title;
471 2b3d32a1 2022-12-30 thomas 	gotd_listen.pid = getpid();
472 2b3d32a1 2022-12-30 thomas 	gotd_listen.fd = gotd_socket;
473 0781db0e 2023-01-06 thomas 	gotd_listen.connection_limits = connection_limits;
474 0781db0e 2023-01-06 thomas 	gotd_listen.nconnection_limits = nconnection_limits;
475 2b3d32a1 2022-12-30 thomas 
476 2b3d32a1 2022-12-30 thomas 	signal_set(&evsigint, SIGINT, listen_sighdlr, NULL);
477 2b3d32a1 2022-12-30 thomas 	signal_set(&evsigterm, SIGTERM, listen_sighdlr, NULL);
478 2b3d32a1 2022-12-30 thomas 	signal_set(&evsighup, SIGHUP, listen_sighdlr, NULL);
479 2b3d32a1 2022-12-30 thomas 	signal_set(&evsigusr1, SIGUSR1, listen_sighdlr, NULL);
480 2b3d32a1 2022-12-30 thomas 	signal(SIGPIPE, SIG_IGN);
481 2b3d32a1 2022-12-30 thomas 
482 2b3d32a1 2022-12-30 thomas 	signal_add(&evsigint, NULL);
483 2b3d32a1 2022-12-30 thomas 	signal_add(&evsigterm, NULL);
484 2b3d32a1 2022-12-30 thomas 	signal_add(&evsighup, NULL);
485 2b3d32a1 2022-12-30 thomas 	signal_add(&evsigusr1, NULL);
486 2b3d32a1 2022-12-30 thomas 
487 2b3d32a1 2022-12-30 thomas 	imsg_init(&iev.ibuf, GOTD_FILENO_MSG_PIPE);
488 2b3d32a1 2022-12-30 thomas 	iev.handler = listen_dispatch;
489 2b3d32a1 2022-12-30 thomas 	iev.events = EV_READ;
490 2b3d32a1 2022-12-30 thomas 	iev.handler_arg = NULL;
491 2b3d32a1 2022-12-30 thomas 	event_set(&iev.ev, iev.ibuf.fd, EV_READ, listen_dispatch, &iev);
492 2b3d32a1 2022-12-30 thomas 	if (event_add(&iev.ev, NULL) == -1)
493 2b3d32a1 2022-12-30 thomas 		fatalx("event add");
494 2b3d32a1 2022-12-30 thomas 
495 2b3d32a1 2022-12-30 thomas 	event_set(&gotd_listen.iev.ev, gotd_listen.fd, EV_READ | EV_PERSIST,
496 2b3d32a1 2022-12-30 thomas 	    gotd_accept, &iev);
497 2b3d32a1 2022-12-30 thomas 	if (event_add(&gotd_listen.iev.ev, NULL))
498 2b3d32a1 2022-12-30 thomas 		fatalx("event add");
499 2b3d32a1 2022-12-30 thomas 	evtimer_set(&gotd_listen.pause.ev, gotd_accept_paused, NULL);
500 2b3d32a1 2022-12-30 thomas 
501 2b3d32a1 2022-12-30 thomas 	event_dispatch();
502 2b3d32a1 2022-12-30 thomas 
503 2b3d32a1 2022-12-30 thomas 	listen_shutdown();
504 2b3d32a1 2022-12-30 thomas }
505 2b3d32a1 2022-12-30 thomas 
506 2b3d32a1 2022-12-30 thomas static void
507 2b3d32a1 2022-12-30 thomas listen_shutdown(void)
508 2b3d32a1 2022-12-30 thomas {
509 2b3d32a1 2022-12-30 thomas 	log_debug("%s: shutting down", gotd_listen.title);
510 2b3d32a1 2022-12-30 thomas 
511 0781db0e 2023-01-06 thomas 	free(gotd_listen.connection_limits);
512 2b3d32a1 2022-12-30 thomas 	if (gotd_listen.fd != -1)
513 2b3d32a1 2022-12-30 thomas 		close(gotd_listen.fd);
514 2b3d32a1 2022-12-30 thomas 
515 2b3d32a1 2022-12-30 thomas 	exit(0);
516 2b3d32a1 2022-12-30 thomas }