1 /* $OpenBSD: control.c,v 1.65 2012/07/09 09:57:53 gilles Exp $ */ 2 3 /* 4 * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org> 5 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include <sys/types.h> 21 #include <sys/queue.h> 22 #include <sys/tree.h> 23 #include <sys/param.h> 24 #include <sys/stat.h> 25 #include <sys/socket.h> 26 #include <sys/un.h> 27 28 #include <err.h> 29 #include <errno.h> 30 #include <event.h> 31 #include <fcntl.h> 32 #include <imsg.h> 33 #include <pwd.h> 34 #include <signal.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <unistd.h> 39 40 #include "smtpd.h" 41 #include "log.h" 42 43 #define CONTROL_BACKLOG 5 44 45 /* control specific headers */ 46 struct { 47 struct event ev; 48 int fd; 49 } control_state; 50 51 void control_imsg(struct imsgev *, struct imsg *); 52 __dead void control_shutdown(void); 53 int control_init(void); 54 void control_listen(void); 55 void control_cleanup(void); 56 void control_accept(int, short, void *); 57 struct ctl_conn *control_connbyfd(int); 58 void control_close(int); 59 void control_sig_handler(int, short, void *); 60 void control_dispatch_ext(int, short, void *); 61 62 struct ctl_connlist ctl_conns; 63 64 void 65 control_imsg(struct imsgev *iev, struct imsg *imsg) 66 { 67 struct ctl_conn *c; 68 69 log_imsg(PROC_CONTROL, iev->proc, imsg); 70 71 if (iev->proc == PROC_SMTP) { 72 switch (imsg->hdr.type) { 73 case IMSG_SMTP_ENQUEUE: 74 c = control_connbyfd(imsg->hdr.peerid); 75 if (c == NULL) 76 return; 77 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, 78 imsg->fd, NULL, 0); 79 return; 80 } 81 } 82 83 errx(1, "control_imsg: unexpected %s imsg", 84 imsg_to_str(imsg->hdr.type)); 85 } 86 87 void 88 control_sig_handler(int sig, short event, void *p) 89 { 90 switch (sig) { 91 case SIGINT: 92 case SIGTERM: 93 control_shutdown(); 94 break; 95 default: 96 fatalx("control_sig_handler: unexpected signal"); 97 } 98 } 99 100 101 pid_t 102 control(void) 103 { 104 struct sockaddr_un sun; 105 int fd; 106 mode_t old_umask; 107 pid_t pid; 108 struct passwd *pw; 109 struct event ev_sigint; 110 struct event ev_sigterm; 111 struct peer peers [] = { 112 { PROC_SCHEDULER, imsg_dispatch }, 113 { PROC_QUEUE, imsg_dispatch }, 114 { PROC_SMTP, imsg_dispatch }, 115 { PROC_MFA, imsg_dispatch }, 116 { PROC_PARENT, imsg_dispatch }, 117 }; 118 119 switch (pid = fork()) { 120 case -1: 121 fatal("control: cannot fork"); 122 case 0: 123 break; 124 default: 125 return (pid); 126 } 127 128 purge_config(PURGE_EVERYTHING); 129 130 pw = env->sc_pw; 131 132 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 133 fatal("control: socket"); 134 135 bzero(&sun, sizeof(sun)); 136 sun.sun_family = AF_UNIX; 137 if (strlcpy(sun.sun_path, SMTPD_SOCKET, 138 sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) 139 fatal("control: socket name too long"); 140 141 if (connect(fd, (struct sockaddr *)&sun, sizeof(sun)) == 0) 142 fatalx("control socket already listening"); 143 144 if (unlink(SMTPD_SOCKET) == -1) 145 if (errno != ENOENT) 146 fatal("control: cannot unlink socket"); 147 148 old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH); 149 if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) { 150 (void)umask(old_umask); 151 fatal("control: bind"); 152 } 153 (void)umask(old_umask); 154 155 if (chmod(SMTPD_SOCKET, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH) == -1) { 156 (void)unlink(SMTPD_SOCKET); 157 fatal("control: chmod"); 158 } 159 160 session_socket_blockmode(fd, BM_NONBLOCK); 161 control_state.fd = fd; 162 163 if (chroot(pw->pw_dir) == -1) 164 fatal("control: chroot"); 165 if (chdir("/") == -1) 166 fatal("control: chdir(\"/\")"); 167 168 smtpd_process = PROC_CONTROL; 169 setproctitle("%s", env->sc_title[smtpd_process]); 170 171 if (setgroups(1, &pw->pw_gid) || 172 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) || 173 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) 174 fatal("control: cannot drop privileges"); 175 176 imsg_callback = control_imsg; 177 event_init(); 178 179 signal_set(&ev_sigint, SIGINT, control_sig_handler, NULL); 180 signal_set(&ev_sigterm, SIGTERM, control_sig_handler, NULL); 181 signal_add(&ev_sigint, NULL); 182 signal_add(&ev_sigterm, NULL); 183 signal(SIGPIPE, SIG_IGN); 184 signal(SIGHUP, SIG_IGN); 185 186 TAILQ_INIT(&ctl_conns); 187 188 config_pipes(peers, nitems(peers)); 189 config_peers(peers, nitems(peers)); 190 control_listen(); 191 192 if (event_dispatch() < 0) 193 fatal("event_dispatch"); 194 control_shutdown(); 195 196 return (0); 197 } 198 199 void 200 control_shutdown(void) 201 { 202 log_info("control process exiting"); 203 _exit(0); 204 } 205 206 void 207 control_listen(void) 208 { 209 int avail = availdesc(); 210 211 if (listen(control_state.fd, CONTROL_BACKLOG) == -1) 212 fatal("control_listen"); 213 avail--; 214 215 event_set(&control_state.ev, control_state.fd, EV_READ|EV_PERSIST, 216 control_accept, NULL); 217 event_add(&control_state.ev, NULL); 218 219 /* guarantee 2 fds to each accepted client */ 220 if ((env->sc_maxconn = avail / 2) < 1) 221 fatalx("control_listen: fd starvation"); 222 } 223 224 void 225 control_cleanup(void) 226 { 227 (void)unlink(SMTPD_SOCKET); 228 } 229 230 /* ARGSUSED */ 231 void 232 control_accept(int listenfd, short event, void *arg) 233 { 234 int connfd; 235 socklen_t len; 236 struct sockaddr_un sun; 237 struct ctl_conn *c; 238 239 len = sizeof(sun); 240 if ((connfd = accept(listenfd, (struct sockaddr *)&sun, &len)) == -1) { 241 if (errno == EINTR || errno == ECONNABORTED) 242 return; 243 fatal("control_accept: accept"); 244 } 245 246 session_socket_blockmode(connfd, BM_NONBLOCK); 247 248 if ((c = calloc(1, sizeof(*c))) == NULL) 249 fatal(NULL); 250 imsg_init(&c->iev.ibuf, connfd); 251 c->iev.handler = control_dispatch_ext; 252 c->iev.events = EV_READ; 253 event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events, 254 c->iev.handler, NULL); 255 event_add(&c->iev.ev, NULL); 256 TAILQ_INSERT_TAIL(&ctl_conns, c, entry); 257 258 if (stat_increment(STATS_CONTROL_SESSION) >= env->sc_maxconn) { 259 log_warnx("ctl client limit hit, disabling new connections"); 260 event_del(&control_state.ev); 261 } 262 } 263 264 struct ctl_conn * 265 control_connbyfd(int fd) 266 { 267 struct ctl_conn *c; 268 269 for (c = TAILQ_FIRST(&ctl_conns); c != NULL && c->iev.ibuf.fd != fd; 270 c = TAILQ_NEXT(c, entry)) 271 ; /* nothing */ 272 273 return (c); 274 } 275 276 void 277 control_close(int fd) 278 { 279 struct ctl_conn *c; 280 281 if ((c = control_connbyfd(fd)) == NULL) { 282 log_warn("control_close: fd %d: not found", fd); 283 return; 284 } 285 TAILQ_REMOVE(&ctl_conns, c, entry); 286 event_del(&c->iev.ev); 287 imsg_clear(&c->iev.ibuf); 288 close(fd); 289 free(c); 290 291 if (stat_decrement(STATS_CONTROL_SESSION) < env->sc_maxconn && 292 !event_pending(&control_state.ev, EV_READ, NULL)) { 293 log_warnx("re-enabling ctl connections"); 294 event_add(&control_state.ev, NULL); 295 } 296 } 297 298 /* ARGSUSED */ 299 void 300 control_dispatch_ext(int fd, short event, void *arg) 301 { 302 struct ctl_conn *c; 303 struct imsg imsg; 304 int n; 305 uid_t euid; 306 gid_t egid; 307 308 if (getpeereid(fd, &euid, &egid) == -1) 309 fatal("getpeereid"); 310 311 if ((c = control_connbyfd(fd)) == NULL) { 312 log_warn("control_dispatch_ext: fd %d: not found", fd); 313 return; 314 } 315 316 if (event & EV_READ) { 317 if ((n = imsg_read(&c->iev.ibuf)) == -1 || n == 0) { 318 control_close(fd); 319 return; 320 } 321 } 322 323 if (event & EV_WRITE) { 324 if (msgbuf_write(&c->iev.ibuf.w) < 0) { 325 control_close(fd); 326 return; 327 } 328 } 329 330 for (;;) { 331 if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) { 332 control_close(fd); 333 return; 334 } 335 336 if (n == 0) 337 break; 338 339 switch (imsg.hdr.type) { 340 case IMSG_SMTP_ENQUEUE: 341 if (env->sc_flags & (SMTPD_SMTP_PAUSED | 342 SMTPD_CONFIGURING | SMTPD_EXITING)) { 343 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 344 NULL, 0); 345 break; 346 } 347 imsg_compose_event(env->sc_ievs[PROC_SMTP], 348 IMSG_SMTP_ENQUEUE, fd, 0, -1, &euid, sizeof(euid)); 349 break; 350 case IMSG_STATS: 351 if (euid) 352 goto badcred; 353 imsg_compose_event(&c->iev, IMSG_STATS, 0, 0, -1, 354 env->stats, sizeof(struct stats)); 355 break; 356 case IMSG_CTL_SHUTDOWN: 357 /* NEEDS_FIX */ 358 log_debug("received shutdown request"); 359 360 if (euid) 361 goto badcred; 362 363 if (env->sc_flags & SMTPD_EXITING) { 364 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 365 NULL, 0); 366 break; 367 } 368 env->sc_flags |= SMTPD_EXITING; 369 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 370 break; 371 case IMSG_CTL_VERBOSE: { 372 int verbose; 373 374 if (euid) 375 goto badcred; 376 377 if (IMSG_DATA_SIZE(&imsg) != sizeof(verbose)) 378 goto badcred; 379 380 memcpy(&verbose, imsg.data, sizeof(verbose)); 381 log_verbose(verbose); 382 imsg_compose_event(env->sc_ievs[PROC_PARENT], IMSG_CTL_VERBOSE, 383 0, 0, -1, &verbose, sizeof(verbose)); 384 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 385 break; 386 } 387 case IMSG_QUEUE_PAUSE_MDA: 388 if (euid) 389 goto badcred; 390 391 if (env->sc_flags & SMTPD_MDA_PAUSED) { 392 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 393 NULL, 0); 394 break; 395 } 396 env->sc_flags |= SMTPD_MDA_PAUSED; 397 imsg_compose_event(env->sc_ievs[PROC_QUEUE], 398 IMSG_QUEUE_PAUSE_MDA, 0, 0, -1, NULL, 0); 399 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 400 break; 401 case IMSG_QUEUE_PAUSE_MTA: 402 if (euid) 403 goto badcred; 404 405 if (env->sc_flags & SMTPD_MTA_PAUSED) { 406 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 407 NULL, 0); 408 break; 409 } 410 env->sc_flags |= SMTPD_MTA_PAUSED; 411 imsg_compose_event(env->sc_ievs[PROC_QUEUE], 412 IMSG_QUEUE_PAUSE_MTA, 0, 0, -1, NULL, 0); 413 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 414 break; 415 case IMSG_SMTP_PAUSE: 416 if (euid) 417 goto badcred; 418 419 if (env->sc_flags & SMTPD_SMTP_PAUSED) { 420 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 421 NULL, 0); 422 break; 423 } 424 env->sc_flags |= SMTPD_SMTP_PAUSED; 425 imsg_compose_event(env->sc_ievs[PROC_SMTP], IMSG_SMTP_PAUSE, 426 0, 0, -1, NULL, 0); 427 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 428 break; 429 case IMSG_QUEUE_RESUME_MDA: 430 if (euid) 431 goto badcred; 432 433 if (! (env->sc_flags & SMTPD_MDA_PAUSED)) { 434 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 435 NULL, 0); 436 break; 437 } 438 env->sc_flags &= ~SMTPD_MDA_PAUSED; 439 imsg_compose_event(env->sc_ievs[PROC_QUEUE], 440 IMSG_QUEUE_RESUME_MDA, 0, 0, -1, NULL, 0); 441 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 442 break; 443 case IMSG_QUEUE_RESUME_MTA: 444 if (euid) 445 goto badcred; 446 447 if (!(env->sc_flags & SMTPD_MTA_PAUSED)) { 448 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 449 NULL, 0); 450 break; 451 } 452 env->sc_flags &= ~SMTPD_MTA_PAUSED; 453 imsg_compose_event(env->sc_ievs[PROC_QUEUE], 454 IMSG_QUEUE_RESUME_MTA, 0, 0, -1, NULL, 0); 455 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 456 break; 457 458 case IMSG_SMTP_RESUME: 459 if (euid) 460 goto badcred; 461 462 if (!(env->sc_flags & SMTPD_SMTP_PAUSED)) { 463 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 464 NULL, 0); 465 break; 466 } 467 env->sc_flags &= ~SMTPD_SMTP_PAUSED; 468 imsg_compose_event(env->sc_ievs[PROC_SMTP], IMSG_SMTP_RESUME, 469 0, 0, -1, NULL, 0); 470 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 471 break; 472 473 case IMSG_SCHEDULER_SCHEDULE: { 474 u_int64_t ullval; 475 476 if (euid) 477 goto badcred; 478 479 ullval = *(u_int64_t *)imsg.data; 480 481 imsg_compose_event(env->sc_ievs[PROC_SCHEDULER], IMSG_SCHEDULER_SCHEDULE, 482 0, 0, -1, &ullval, sizeof(ullval)); 483 484 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 485 break; 486 } 487 488 case IMSG_SCHEDULER_REMOVE: { 489 u_int64_t ullval; 490 491 if (euid) 492 goto badcred; 493 494 ullval = *(u_int64_t *)imsg.data; 495 496 imsg_compose_event(env->sc_ievs[PROC_SCHEDULER], IMSG_SCHEDULER_REMOVE, 497 0, 0, -1, &ullval, sizeof(ullval)); 498 499 imsg_compose_event(&c->iev, IMSG_CTL_OK, 0, 0, -1, NULL, 0); 500 break; 501 } 502 default: 503 log_debug("control_dispatch_ext: " 504 "error handling %s imsg", 505 imsg_to_str(imsg.hdr.type)); 506 break; 507 } 508 imsg_free(&imsg); 509 continue; 510 511 badcred: 512 imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, 513 NULL, 0); 514 } 515 516 imsg_event_add(&c->iev); 517 } 518