1 /* $OpenBSD: proc.c,v 1.19 2015/12/07 12:33:08 reyk Exp $ */ 2 3 /* 4 * Copyright (c) 2010 - 2014 Reyk Floeter <reyk@openbsd.org> 5 * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@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/socket.h> 23 #include <sys/wait.h> 24 25 #include <stdio.h> 26 #include <stdlib.h> 27 #include <unistd.h> 28 #include <string.h> 29 #include <errno.h> 30 #include <signal.h> 31 #include <pwd.h> 32 #include <event.h> 33 #include <imsg.h> 34 35 #include "snmpd.h" 36 37 void proc_open(struct privsep *, struct privsep_proc *, 38 struct privsep_proc *, size_t); 39 void proc_close(struct privsep *); 40 int proc_ispeer(struct privsep_proc *, unsigned int, enum privsep_procid); 41 void proc_shutdown(struct privsep_proc *); 42 void proc_sig_handler(int, short, void *); 43 void proc_range(struct privsep *, enum privsep_procid, int *, int *); 44 int proc_dispatch_null(int, struct privsep_proc *, struct imsg *); 45 46 int 47 proc_ispeer(struct privsep_proc *procs, unsigned int nproc, 48 enum privsep_procid type) 49 { 50 unsigned int i; 51 52 for (i = 0; i < nproc; i++) 53 if (procs[i].p_id == type) 54 return (1); 55 return (0); 56 } 57 58 void 59 proc_init(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc) 60 { 61 unsigned int i, j, src, dst; 62 struct privsep_pipes *pp; 63 64 /* 65 * Allocate pipes for all process instances (incl. parent) 66 * 67 * - ps->ps_pipes: N:M mapping 68 * N source processes connected to M destination processes: 69 * [src][instances][dst][instances], for example 70 * [PROC_RELAY][3][PROC_CA][3] 71 * 72 * - ps->ps_pp: per-process 1:M part of ps->ps_pipes 73 * Each process instance has a destination array of socketpair fds: 74 * [dst][instances], for example 75 * [PROC_PARENT][0] 76 */ 77 for (src = 0; src < PROC_MAX; src++) { 78 /* Allocate destination array for each process */ 79 if ((ps->ps_pipes[src] = calloc(ps->ps_ninstances, 80 sizeof(struct privsep_pipes))) == NULL) 81 fatal("proc_init: calloc"); 82 83 for (i = 0; i < ps->ps_ninstances; i++) { 84 pp = &ps->ps_pipes[src][i]; 85 86 for (dst = 0; dst < PROC_MAX; dst++) { 87 /* Allocate maximum fd integers */ 88 if ((pp->pp_pipes[dst] = 89 calloc(ps->ps_ninstances, 90 sizeof(int))) == NULL) 91 fatal("proc_init: calloc"); 92 93 /* Mark fd as unused */ 94 for (j = 0; j < ps->ps_ninstances; j++) 95 pp->pp_pipes[dst][j] = -1; 96 } 97 } 98 } 99 100 /* 101 * Setup and run the parent and its children 102 */ 103 privsep_process = PROC_PARENT; 104 ps->ps_instances[PROC_PARENT] = 1; 105 ps->ps_title[PROC_PARENT] = "parent"; 106 ps->ps_pid[PROC_PARENT] = getpid(); 107 ps->ps_pp = &ps->ps_pipes[privsep_process][0]; 108 109 for (i = 0; i < nproc; i++) { 110 /* Default to 1 process instance */ 111 if (ps->ps_instances[procs[i].p_id] < 1) 112 ps->ps_instances[procs[i].p_id] = 1; 113 ps->ps_title[procs[i].p_id] = procs[i].p_title; 114 } 115 116 proc_open(ps, NULL, procs, nproc); 117 118 /* Engage! */ 119 for (i = 0; i < nproc; i++) 120 ps->ps_pid[procs[i].p_id] = (*procs[i].p_init)(ps, &procs[i]); 121 } 122 123 void 124 proc_kill(struct privsep *ps) 125 { 126 pid_t pid; 127 unsigned int i; 128 129 if (privsep_process != PROC_PARENT) 130 return; 131 132 for (i = 0; i < PROC_MAX; i++) { 133 if (ps->ps_pid[i] == 0) 134 continue; 135 killpg(ps->ps_pid[i], SIGTERM); 136 } 137 138 do { 139 pid = waitpid(WAIT_ANY, NULL, 0); 140 } while (pid != -1 || (pid == -1 && errno == EINTR)); 141 142 proc_close(ps); 143 } 144 145 void 146 proc_open(struct privsep *ps, struct privsep_proc *p, 147 struct privsep_proc *procs, size_t nproc) 148 { 149 struct privsep_pipes *pa, *pb; 150 int fds[2]; 151 unsigned int i, j, src, proc; 152 153 if (p == NULL) 154 src = privsep_process; /* parent */ 155 else 156 src = p->p_id; 157 158 /* 159 * Open socket pairs for our peers 160 */ 161 for (proc = 0; proc < nproc; proc++) { 162 procs[proc].p_ps = ps; 163 procs[proc].p_env = ps->ps_env; 164 if (procs[proc].p_cb == NULL) 165 procs[proc].p_cb = proc_dispatch_null; 166 167 for (i = 0; i < ps->ps_instances[src]; i++) { 168 for (j = 0; j < ps->ps_instances[procs[proc].p_id]; 169 j++) { 170 pa = &ps->ps_pipes[src][i]; 171 pb = &ps->ps_pipes[procs[proc].p_id][j]; 172 173 /* Check if fds are already set by peer */ 174 if (pa->pp_pipes[procs[proc].p_id][j] != -1) 175 continue; 176 177 if (socketpair(AF_UNIX, 178 SOCK_STREAM | SOCK_NONBLOCK, 179 PF_UNSPEC, fds) == -1) 180 fatal("socketpair"); 181 182 pa->pp_pipes[procs[proc].p_id][j] = fds[0]; 183 pb->pp_pipes[src][i] = fds[1]; 184 } 185 } 186 } 187 } 188 189 void 190 proc_listen(struct privsep *ps, struct privsep_proc *procs, size_t nproc) 191 { 192 unsigned int i, dst, src, n, m; 193 struct privsep_pipes *pp; 194 195 /* 196 * Close unused pipes 197 */ 198 for (src = 0; src < PROC_MAX; src++) { 199 for (n = 0; n < ps->ps_instances[src]; n++) { 200 /* Ingore current process */ 201 if (src == (unsigned int)privsep_process && 202 n == ps->ps_instance) 203 continue; 204 205 pp = &ps->ps_pipes[src][n]; 206 207 for (dst = 0; dst < PROC_MAX; dst++) { 208 if (src == dst) 209 continue; 210 for (m = 0; m < ps->ps_instances[dst]; m++) { 211 if (pp->pp_pipes[dst][m] == -1) 212 continue; 213 214 /* Close and invalidate fd */ 215 close(pp->pp_pipes[dst][m]); 216 pp->pp_pipes[dst][m] = -1; 217 } 218 } 219 } 220 } 221 222 src = privsep_process; 223 ps->ps_pp = pp = &ps->ps_pipes[src][ps->ps_instance]; 224 225 /* 226 * Listen on appropriate pipes 227 */ 228 for (i = 0; i < nproc; i++) { 229 dst = procs[i].p_id; 230 231 if (src == dst) 232 fatal("proc_listen: cannot peer with oneself"); 233 234 if ((ps->ps_ievs[dst] = calloc(ps->ps_instances[dst], 235 sizeof(struct imsgev))) == NULL) 236 fatal("proc_open"); 237 238 for (n = 0; n < ps->ps_instances[dst]; n++) { 239 if (pp->pp_pipes[dst][n] == -1) 240 continue; 241 242 imsg_init(&(ps->ps_ievs[dst][n].ibuf), 243 pp->pp_pipes[dst][n]); 244 ps->ps_ievs[dst][n].handler = proc_dispatch; 245 ps->ps_ievs[dst][n].events = EV_READ; 246 ps->ps_ievs[dst][n].proc = &procs[i]; 247 ps->ps_ievs[dst][n].data = &ps->ps_ievs[dst][n]; 248 procs[i].p_instance = n; 249 250 event_set(&(ps->ps_ievs[dst][n].ev), 251 ps->ps_ievs[dst][n].ibuf.fd, 252 ps->ps_ievs[dst][n].events, 253 ps->ps_ievs[dst][n].handler, 254 ps->ps_ievs[dst][n].data); 255 event_add(&(ps->ps_ievs[dst][n].ev), NULL); 256 } 257 } 258 } 259 260 void 261 proc_close(struct privsep *ps) 262 { 263 unsigned int dst, n; 264 struct privsep_pipes *pp; 265 266 if (ps == NULL) 267 return; 268 269 pp = ps->ps_pp; 270 271 for (dst = 0; dst < PROC_MAX; dst++) { 272 if (ps->ps_ievs[dst] == NULL) 273 continue; 274 275 for (n = 0; n < ps->ps_instances[dst]; n++) { 276 if (pp->pp_pipes[dst][n] == -1) 277 continue; 278 279 /* Cancel the fd, close and invalidate the fd */ 280 event_del(&(ps->ps_ievs[dst][n].ev)); 281 imsg_clear(&(ps->ps_ievs[dst][n].ibuf)); 282 close(pp->pp_pipes[dst][n]); 283 pp->pp_pipes[dst][n] = -1; 284 } 285 free(ps->ps_ievs[dst]); 286 } 287 } 288 289 void 290 proc_shutdown(struct privsep_proc *p) 291 { 292 struct privsep *ps = p->p_ps; 293 294 if (p->p_id == PROC_CONTROL && ps) 295 control_cleanup(&ps->ps_csock); 296 297 if (p->p_shutdown != NULL) 298 (*p->p_shutdown)(); 299 300 proc_close(ps); 301 302 log_info("%s exiting, pid %d", p->p_title, getpid()); 303 304 _exit(0); 305 } 306 307 void 308 proc_sig_handler(int sig, short event, void *arg) 309 { 310 struct privsep_proc *p = arg; 311 312 switch (sig) { 313 case SIGINT: 314 case SIGTERM: 315 proc_shutdown(p); 316 break; 317 case SIGCHLD: 318 case SIGHUP: 319 case SIGPIPE: 320 case SIGUSR1: 321 /* ignore */ 322 break; 323 default: 324 fatalx("proc_sig_handler: unexpected signal"); 325 /* NOTREACHED */ 326 } 327 } 328 329 pid_t 330 proc_run(struct privsep *ps, struct privsep_proc *p, 331 struct privsep_proc *procs, unsigned int nproc, 332 void (*run)(struct privsep *, struct privsep_proc *, void *), void *arg) 333 { 334 pid_t pid; 335 struct passwd *pw; 336 const char *root; 337 struct control_sock *rcs; 338 unsigned int n; 339 340 if (ps->ps_noaction) 341 return (0); 342 343 proc_open(ps, p, procs, nproc); 344 345 /* Fork child handlers */ 346 switch (pid = fork()) { 347 case -1: 348 fatal("proc_run: cannot fork"); 349 case 0: 350 log_procinit(p->p_title); 351 352 /* Set the process group of the current process */ 353 setpgid(0, 0); 354 break; 355 default: 356 return (pid); 357 } 358 359 pw = ps->ps_pw; 360 361 if (p->p_id == PROC_CONTROL && ps->ps_instance == 0) { 362 if (control_init(ps, &ps->ps_csock) == -1) 363 fatalx(__func__); 364 TAILQ_FOREACH(rcs, &ps->ps_rcsocks, cs_entry) 365 if (control_init(ps, rcs) == -1) 366 fatalx(__func__); 367 } 368 369 /* Change root directory */ 370 if (p->p_chroot != NULL) 371 root = p->p_chroot; 372 else 373 root = pw->pw_dir; 374 375 if (chroot(root) == -1) 376 fatal("proc_run: chroot"); 377 if (chdir("/") == -1) 378 fatal("proc_run: chdir(\"/\")"); 379 380 privsep_process = p->p_id; 381 382 setproctitle("%s", p->p_title); 383 384 if (setgroups(1, &pw->pw_gid) || 385 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) || 386 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) 387 fatal("proc_run: cannot drop privileges"); 388 389 /* Fork child handlers */ 390 for (n = 1; n < ps->ps_instances[p->p_id]; n++) { 391 if (fork() == 0) { 392 ps->ps_instance = p->p_instance = n; 393 break; 394 } 395 } 396 397 #ifdef DEBUG 398 log_debug("%s: %s %d/%d, pid %d", __func__, p->p_title, 399 ps->ps_instance + 1, ps->ps_instances[p->p_id], getpid()); 400 #endif 401 402 event_init(); 403 404 signal_set(&ps->ps_evsigint, SIGINT, proc_sig_handler, p); 405 signal_set(&ps->ps_evsigterm, SIGTERM, proc_sig_handler, p); 406 signal_set(&ps->ps_evsigchld, SIGCHLD, proc_sig_handler, p); 407 signal_set(&ps->ps_evsighup, SIGHUP, proc_sig_handler, p); 408 signal_set(&ps->ps_evsigpipe, SIGPIPE, proc_sig_handler, p); 409 signal_set(&ps->ps_evsigusr1, SIGUSR1, proc_sig_handler, p); 410 411 signal_add(&ps->ps_evsigint, NULL); 412 signal_add(&ps->ps_evsigterm, NULL); 413 signal_add(&ps->ps_evsigchld, NULL); 414 signal_add(&ps->ps_evsighup, NULL); 415 signal_add(&ps->ps_evsigpipe, NULL); 416 signal_add(&ps->ps_evsigusr1, NULL); 417 418 proc_listen(ps, procs, nproc); 419 420 if (p->p_id == PROC_CONTROL && ps->ps_instance == 0) { 421 TAILQ_INIT(&ctl_conns); 422 if (control_listen(&ps->ps_csock) == -1) 423 fatalx(__func__); 424 TAILQ_FOREACH(rcs, &ps->ps_rcsocks, cs_entry) 425 if (control_listen(rcs) == -1) 426 fatalx(__func__); 427 } 428 429 if (run != NULL) 430 run(ps, p, arg); 431 432 event_dispatch(); 433 434 proc_shutdown(p); 435 436 return (0); 437 } 438 439 void 440 proc_dispatch(int fd, short event, void *arg) 441 { 442 struct imsgev *iev = arg; 443 struct privsep_proc *p = iev->proc; 444 struct privsep *ps = p->p_ps; 445 struct imsgbuf *ibuf; 446 struct imsg imsg; 447 ssize_t n; 448 int verbose; 449 const char *title; 450 451 title = ps->ps_title[privsep_process]; 452 ibuf = &iev->ibuf; 453 454 if (event & EV_READ) { 455 if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN) 456 fatal(__func__); 457 if (n == 0) { 458 /* this pipe is dead, so remove the event handler */ 459 event_del(&iev->ev); 460 event_loopexit(NULL); 461 return; 462 } 463 } 464 465 if (event & EV_WRITE) { 466 if (msgbuf_write(&ibuf->w) <= 0 && errno != EAGAIN) 467 fatal(__func__); 468 } 469 470 for (;;) { 471 if ((n = imsg_get(ibuf, &imsg)) == -1) 472 fatal(__func__); 473 if (n == 0) 474 break; 475 476 #if DEBUG > 1 477 log_debug("%s: %s %d got imsg %d from %s %d", 478 __func__, title, ps->ps_instance + 1, 479 imsg.hdr.type, p->p_title, p->p_instance); 480 #endif 481 482 /* 483 * Check the message with the program callback 484 */ 485 if ((p->p_cb)(fd, p, &imsg) == 0) { 486 /* Message was handled by the callback, continue */ 487 imsg_free(&imsg); 488 continue; 489 } 490 491 /* 492 * Generic message handling 493 */ 494 switch (imsg.hdr.type) { 495 case IMSG_CTL_VERBOSE: 496 IMSG_SIZE_CHECK(&imsg, &verbose); 497 memcpy(&verbose, imsg.data, sizeof(verbose)); 498 log_verbose(verbose); 499 break; 500 default: 501 log_warnx("%s: %s %d got invalid imsg %d from %s %d", 502 __func__, title, ps->ps_instance + 1, 503 imsg.hdr.type, p->p_title, p->p_instance); 504 fatalx(__func__); 505 } 506 imsg_free(&imsg); 507 } 508 imsg_event_add(iev); 509 } 510 511 int 512 proc_dispatch_null(int fd, struct privsep_proc *p, struct imsg *imsg) 513 { 514 return (-1); 515 } 516 517 /* 518 * imsg helper functions 519 */ 520 521 void 522 imsg_event_add(struct imsgev *iev) 523 { 524 if (iev->handler == NULL) { 525 imsg_flush(&iev->ibuf); 526 return; 527 } 528 529 iev->events = EV_READ; 530 if (iev->ibuf.w.queued) 531 iev->events |= EV_WRITE; 532 533 event_del(&iev->ev); 534 event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data); 535 event_add(&iev->ev, NULL); 536 } 537 538 int 539 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid, 540 pid_t pid, int fd, void *data, uint16_t datalen) 541 { 542 int ret; 543 544 if ((ret = imsg_compose(&iev->ibuf, type, peerid, 545 pid, fd, data, datalen)) == -1) 546 return (ret); 547 imsg_event_add(iev); 548 return (ret); 549 } 550 551 int 552 imsg_composev_event(struct imsgev *iev, uint16_t type, uint32_t peerid, 553 pid_t pid, int fd, const struct iovec *iov, int iovcnt) 554 { 555 int ret; 556 557 if ((ret = imsg_composev(&iev->ibuf, type, peerid, 558 pid, fd, iov, iovcnt)) == -1) 559 return (ret); 560 imsg_event_add(iev); 561 return (ret); 562 } 563 564 void 565 proc_range(struct privsep *ps, enum privsep_procid id, int *n, int *m) 566 { 567 if (*n == -1) { 568 /* Use a range of all target instances */ 569 *n = 0; 570 *m = ps->ps_instances[id]; 571 } else { 572 /* Use only a single slot of the specified peer process */ 573 *m = *n + 1; 574 } 575 } 576 577 int 578 proc_compose_imsg(struct privsep *ps, enum privsep_procid id, int n, 579 uint16_t type, uint32_t peerid, int fd, void *data, uint16_t datalen) 580 { 581 int m; 582 583 proc_range(ps, id, &n, &m); 584 for (; n < m; n++) { 585 if (imsg_compose_event(&ps->ps_ievs[id][n], 586 type, peerid, 0, fd, data, datalen) == -1) 587 return (-1); 588 } 589 590 return (0); 591 } 592 593 int 594 proc_compose(struct privsep *ps, enum privsep_procid id, 595 uint16_t type, void *data, uint16_t datalen) 596 { 597 return (proc_compose_imsg(ps, id, -1, type, -1, -1, data, datalen)); 598 } 599 600 int 601 proc_composev_imsg(struct privsep *ps, enum privsep_procid id, int n, 602 uint16_t type, uint32_t peerid, int fd, const struct iovec *iov, int iovcnt) 603 { 604 int m; 605 606 proc_range(ps, id, &n, &m); 607 for (; n < m; n++) 608 if (imsg_composev_event(&ps->ps_ievs[id][n], 609 type, peerid, 0, fd, iov, iovcnt) == -1) 610 return (-1); 611 612 return (0); 613 } 614 615 int 616 proc_composev(struct privsep *ps, enum privsep_procid id, 617 uint16_t type, const struct iovec *iov, int iovcnt) 618 { 619 return (proc_composev_imsg(ps, id, -1, type, -1, -1, iov, iovcnt)); 620 } 621 622 int 623 proc_forward_imsg(struct privsep *ps, struct imsg *imsg, 624 enum privsep_procid id, int n) 625 { 626 return (proc_compose_imsg(ps, id, n, imsg->hdr.type, 627 imsg->hdr.peerid, imsg->fd, imsg->data, IMSG_DATA_SIZE(imsg))); 628 } 629 630 struct imsgbuf * 631 proc_ibuf(struct privsep *ps, enum privsep_procid id, int n) 632 { 633 int m; 634 635 proc_range(ps, id, &n, &m); 636 return (&ps->ps_ievs[id][n].ibuf); 637 } 638 639 struct imsgev * 640 proc_iev(struct privsep *ps, enum privsep_procid id, int n) 641 { 642 int m; 643 644 proc_range(ps, id, &n, &m); 645 return (&ps->ps_ievs[id][n]); 646 } 647