gotwebd/sockets.c

   1 /*
   2  * Copyright (c) 2016, 2019, 2020-2021 Tracey Emery <tracey@traceyemery.net>
   3  * Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
   4  * Copyright (c) 2013 David Gwynne <dlg@openbsd.org>
   5  * Copyright (c) 2013 Florian Obser <florian@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 "got_compat.h"
  21
  22 #include <sys/param.h>
  23 #include <sys/ioctl.h>
  24 #include <sys/queue.h>
  25 #include <sys/wait.h>
  26 #include <sys/uio.h>
  27 #include <sys/resource.h>
  28 #include <sys/socket.h>
  29 #include <sys/stat.h>
  30 #include <sys/time.h>
  31 #include <sys/types.h>
  32 #include <sys/mman.h>
  33 #include <sys/un.h>
  34
  35 #include <net/if.h>
  36 #include <netinet/in.h>
  37
  38 #include <errno.h>
  39 #include <event.h>
  40 #include <fcntl.h>
  41 #include <ifaddrs.h>
  42 #include <limits.h>
  43 #include <netdb.h>
  44 #include <poll.h>
  45 #include <pwd.h>
  46 #include <stddef.h>
  47 #include <stdio.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include <unistd.h>
  51
  52 #include "got_error.h"
  53 #include "got_opentemp.h"
  54 #include "got_reference.h"
  55 #include "got_repository.h"
  56 #include "got_privsep.h"
  57
  58 #include "gotwebd.h"
  59 #include "log.h"
  60 #include "tmpl.h"
  61
  62 #define SOCKS_BACKLOG 5
  63 #define MAXIMUM(a, b)   (((a) > (b)) ? (a) : (b))
  64
  65 volatile int client_cnt;
  66
  67 static struct timeval   timeout = { TIMEOUT_DEFAULT, 0 };
  68
  69 static void      sockets_sighdlr(int, short, void *);
  70 static void      sockets_shutdown(void);
  71 static void      sockets_launch(void);
  72 static void      sockets_accept_paused(int, short, void *);
  73 static void      sockets_rlimit(int);
  74
  75 static void      sockets_dispatch_main(int, short, void *);
  76 static int       sockets_unix_socket_listen(struct gotwebd *, struct socket *);
  77 static int       sockets_create_socket(struct address *);
  78 static int       sockets_accept_reserve(int, struct sockaddr *, socklen_t *,
  79                     int, volatile int *);
  80
  81 static struct socket *sockets_conf_new_socket(struct gotwebd *,
  82                     int, struct address *);
  83
  84 int cgi_inflight = 0;
  85
  86 void
  87 sockets(struct gotwebd *env, int fd)
  88 {
  89         struct event     sighup, sigint, sigusr1, sigchld, sigterm;
  90
  91         event_init();
  92
  93         sockets_rlimit(-1);
  94
  95         if ((env->iev_parent = malloc(sizeof(*env->iev_parent))) == NULL)
  96                 fatal("malloc");
  97         if (imsgbuf_init(&env->iev_parent->ibuf, fd) == -1)
  98                 fatal("imsgbuf_init");
  99         imsgbuf_allow_fdpass(&env->iev_parent->ibuf);
 100         env->iev_parent->handler = sockets_dispatch_main;
 101         env->iev_parent->data = env->iev_parent;
 102         event_set(&env->iev_parent->ev, fd, EV_READ, sockets_dispatch_main,
 103             env->iev_parent);
 104         event_add(&env->iev_parent->ev, NULL);
 105
 106         signal(SIGPIPE, SIG_IGN);
 107
 108         signal_set(&sighup, SIGHUP, sockets_sighdlr, env);
 109         signal_add(&sighup, NULL);
 110         signal_set(&sigint, SIGINT, sockets_sighdlr, env);
 111         signal_add(&sigint, NULL);
 112         signal_set(&sigusr1, SIGUSR1, sockets_sighdlr, env);
 113         signal_add(&sigusr1, NULL);
 114         signal_set(&sigchld, SIGCHLD, sockets_sighdlr, env);
 115         signal_add(&sigchld, NULL);
 116         signal_set(&sigterm, SIGTERM, sockets_sighdlr, env);
 117         signal_add(&sigterm, NULL);
 118
 119 #ifndef PROFILE
 120         if (pledge("stdio rpath inet recvfd proc exec sendfd unveil",
 121             NULL) == -1)
 122                 fatal("pledge");
 123 #endif
 124
 125         event_dispatch();
 126         sockets_shutdown();
 127 }
 128
 129 void
 130 sockets_parse_sockets(struct gotwebd *env)
 131 {
 132         struct address *a;
 133         struct socket *new_sock = NULL;
 134         int sock_id = 1;
 135
 136         TAILQ_FOREACH(a, &env->addresses, entry) {
 137                 new_sock = sockets_conf_new_socket(env, sock_id, a);
 138                 if (new_sock) {
 139                         sock_id++;
 140                         TAILQ_INSERT_TAIL(&env->sockets,
 141                             new_sock, entry);
 142                 }
 143         }
 144 }
 145
 146 static struct socket *
 147 sockets_conf_new_socket(struct gotwebd *env, int id, struct address *a)
 148 {
 149         struct socket *sock;
 150         struct address *acp;
 151
 152         if ((sock = calloc(1, sizeof(*sock))) == NULL)
 153                 fatalx("%s: calloc", __func__);
 154
 155         sock->conf.id = id;
 156         sock->fd = -1;
 157         sock->conf.af_type = a->ss.ss_family;
 158
 159         if (a->ss.ss_family == AF_UNIX) {
 160                 struct sockaddr_un *sun;
 161
 162                 sun = (struct sockaddr_un *)&a->ss;
 163                 if (strlcpy(sock->conf.unix_socket_name, sun->sun_path,
 164                     sizeof(sock->conf.unix_socket_name)) >=
 165                     sizeof(sock->conf.unix_socket_name))
 166                         fatalx("unix socket path too long: %s", sun->sun_path);
 167         }
 168
 169         sock->conf.fcgi_socket_port = a->port;
 170
 171         acp = &sock->conf.addr;
 172
 173         memcpy(&acp->ss, &a->ss, sizeof(acp->ss));
 174         acp->slen = a->slen;
 175         acp->ai_family = a->ai_family;
 176         acp->ai_socktype = a->ai_socktype;
 177         acp->ai_protocol = a->ai_protocol;
 178         acp->port = a->port;
 179         if (*a->ifname != '\0') {
 180                 if (strlcpy(acp->ifname, a->ifname,
 181                     sizeof(acp->ifname)) >= sizeof(acp->ifname)) {
 182                         fatalx("%s: interface name truncated",
 183                             __func__);
 184                 }
 185         }
 186
 187         return (sock);
 188 }
 189
 190 static void
 191 sockets_launch(void)
 192 {
 193         struct socket *sock;
 194         struct server *srv;
 195         const struct got_error *error;
 196
 197         TAILQ_FOREACH(sock, &gotwebd_env->sockets, entry) {
 198                 log_info("%s: configuring socket %d (%d)", __func__,
 199                     sock->conf.id, sock->fd);
 200
 201                 event_set(&sock->ev, sock->fd, EV_READ | EV_PERSIST,
 202                     sockets_socket_accept, sock);
 203
 204                 if (event_add(&sock->ev, NULL))
 205                         fatalx("event add sock");
 206
 207                 evtimer_set(&sock->pause, sockets_accept_paused, sock);
 208
 209                 log_info("%s: running socket listener %d", __func__,
 210                     sock->conf.id);
 211         }
 212
 213         TAILQ_FOREACH(srv, &gotwebd_env->servers, entry) {
 214                 if (unveil(srv->repos_path, "r") == -1)
 215                         fatal("unveil %s", srv->repos_path);
 216         }
 217
 218         error = got_privsep_unveil_exec_helpers();
 219         if (error)
 220                 fatal("%s", error->msg);
 221
 222         if (unveil(NULL, NULL) == -1)
 223                 fatal("unveil");
 224 }
 225
 226 void
 227 sockets_purge(struct gotwebd *env)
 228 {
 229         struct socket *sock, *tsock;
 230
 231         /* shutdown and remove sockets */
 232         TAILQ_FOREACH_SAFE(sock, &env->sockets, entry, tsock) {
 233                 if (event_initialized(&sock->ev))
 234                         event_del(&sock->ev);
 235                 if (evtimer_initialized(&sock->evt))
 236                         evtimer_del(&sock->evt);
 237                 if (evtimer_initialized(&sock->pause))
 238                         evtimer_del(&sock->pause);
 239                 if (sock->fd != -1)
 240                         close(sock->fd);
 241                 TAILQ_REMOVE(&env->sockets, sock, entry);
 242                 free(sock);
 243         }
 244 }
 245
 246 static void
 247 sockets_dispatch_main(int fd, short event, void *arg)
 248 {
 249         struct imsgev           *iev = arg;
 250         struct imsgbuf          *ibuf;
 251         struct imsg              imsg;
 252         struct gotwebd          *env = gotwebd_env;
 253         ssize_t                  n;
 254         int                      shut = 0;
 255
 256         ibuf = &iev->ibuf;
 257
 258         if (event & EV_READ) {
 259                 if ((n = imsgbuf_read(ibuf)) == -1)
 260                         fatal("imsgbuf_read error");
 261                 if (n == 0)     /* Connection closed */
 262                         shut = 1;
 263         }
 264         if (event & EV_WRITE) {
 265                 if (imsgbuf_write(ibuf) == -1)
 266                         fatal("imsgbuf_write");
 267         }
 268
 269         for (;;) {
 270                 if ((n = imsg_get(ibuf, &imsg)) == -1)
 271                         fatal("imsg_get");
 272                 if (n == 0)     /* No more messages. */
 273                         break;
 274
 275                 switch (imsg.hdr.type) {
 276                 case IMSG_CFG_SRV:
 277                         config_getserver(env, &imsg);
 278                         break;
 279                 case IMSG_CFG_SOCK:
 280                         config_getsock(env, &imsg);
 281                         break;
 282                 case IMSG_CFG_FD:
 283                         config_getfd(env, &imsg);
 284                         break;
 285                 case IMSG_CFG_DONE:
 286                         config_getcfg(env, &imsg);
 287                         break;
 288                 case IMSG_CTL_START:
 289                         sockets_launch();
 290                         break;
 291                 default:
 292                         fatalx("%s: unknown imsg type %d", __func__,
 293                             imsg.hdr.type);
 294                 }
 295
 296                 imsg_free(&imsg);
 297         }
 298
 299         if (!shut)
 300                 imsg_event_add(iev);
 301         else {
 302                 /* This pipe is dead.  Remove its event handler */
 303                 event_del(&iev->ev);
 304                 event_loopexit(NULL);
 305         }
 306 }
 307
 308 static void
 309 sockets_sighdlr(int sig, short event, void *arg)
 310 {
 311         switch (sig) {
 312         case SIGHUP:
 313                 log_info("%s: ignoring SIGHUP", __func__);
 314                 break;
 315         case SIGPIPE:
 316                 log_info("%s: ignoring SIGPIPE", __func__);
 317                 break;
 318         case SIGUSR1:
 319                 log_info("%s: ignoring SIGUSR1", __func__);
 320                 break;
 321         case SIGCHLD:
 322                 break;
 323         case SIGINT:
 324         case SIGTERM:
 325                 sockets_shutdown();
 326                 break;
 327         default:
 328                 log_info("SIGNAL: %d", sig);
 329                 fatalx("unexpected signal");
 330         }
 331 }
 332
 333 static void
 334 sockets_shutdown(void)
 335 {
 336         sockets_purge(gotwebd_env);
 337
 338         /* clean servers */
 339         while (!TAILQ_EMPTY(&gotwebd_env->servers)) {
 340                 struct server *srv;
 341
 342                 srv = TAILQ_FIRST(&gotwebd_env->servers);
 343                 TAILQ_REMOVE(&gotwebd_env->servers, srv, entry);
 344                 free(srv);
 345         }
 346
 347         while (!TAILQ_EMPTY(&gotwebd_env->addresses)) {
 348                 struct address *h;
 349
 350                 h = TAILQ_FIRST(&gotwebd_env->addresses);
 351                 TAILQ_REMOVE(&gotwebd_env->addresses, h, entry);
 352                 free(h);
 353         }
 354
 355         imsgbuf_clear(&gotwebd_env->iev_parent->ibuf);
 356         free(gotwebd_env->iev_parent);
 357         free(gotwebd_env);
 358
 359         exit(0);
 360 }
 361
 362 int
 363 sockets_privinit(struct gotwebd *env, struct socket *sock)
 364 {
 365         if (sock->conf.af_type == AF_UNIX) {
 366                 log_info("%s: initializing unix socket %s", __func__,
 367                     sock->conf.unix_socket_name);
 368                 sock->fd = sockets_unix_socket_listen(env, sock);
 369                 if (sock->fd == -1)
 370                         return -1;
 371         }
 372
 373         if (sock->conf.af_type == AF_INET || sock->conf.af_type == AF_INET6) {
 374                 log_info("%s: initializing %s FCGI socket on port %d",
 375                     __func__, sock->conf.af_type == AF_INET ? "inet" : "inet6",
 376                     sock->conf.fcgi_socket_port);
 377                 sock->fd = sockets_create_socket(&sock->conf.addr);
 378                 if (sock->fd == -1)
 379                         return -1;
 380         }
 381
 382         return 0;
 383 }
 384
 385 static int
 386 sockets_unix_socket_listen(struct gotwebd *env, struct socket *sock)
 387 {
 388         int u_fd = -1;
 389         mode_t old_umask, mode;
 390         int flags = SOCK_STREAM | SOCK_NONBLOCK;
 391
 392 #ifdef SOCK_CLOEXEC
 393         flags |= SOCK_CLOEXEC;
 394 #endif
 395
 396         u_fd = socket(AF_UNIX, flags, 0);
 397         if (u_fd == -1) {
 398                 log_warn("%s: socket", __func__);
 399                 return -1;
 400         }
 401
 402         if (unlink(sock->conf.unix_socket_name) == -1) {
 403                 if (errno != ENOENT) {
 404                         log_warn("%s: unlink %s", __func__,
 405                             sock->conf.unix_socket_name);
 406                         close(u_fd);
 407                         return -1;
 408                 }
 409         }
 410
 411         old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
 412         mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP;
 413
 414         if (bind(u_fd, (struct sockaddr *)&sock->conf.addr.ss,
 415             sock->conf.addr.slen) == -1) {
 416                 log_warn("%s: bind: %s", __func__, sock->conf.unix_socket_name);
 417                 close(u_fd);
 418                 (void)umask(old_umask);
 419                 return -1;
 420         }
 421
 422         (void)umask(old_umask);
 423
 424         if (chmod(sock->conf.unix_socket_name, mode) == -1) {
 425                 log_warn("%s: chmod", __func__);
 426                 close(u_fd);
 427                 (void)unlink(sock->conf.unix_socket_name);
 428                 return -1;
 429         }
 430
 431         if (chown(sock->conf.unix_socket_name, env->pw->pw_uid,
 432             env->pw->pw_gid) == -1) {
 433                 log_warn("%s: chown", __func__);
 434                 close(u_fd);
 435                 (void)unlink(sock->conf.unix_socket_name);
 436                 return -1;
 437         }
 438
 439         if (listen(u_fd, SOCKS_BACKLOG) == -1) {
 440                 log_warn("%s: listen", __func__);
 441                 return -1;
 442         }
 443
 444         return u_fd;
 445 }
 446
 447 static int
 448 sockets_create_socket(struct address *a)
 449 {
 450         int fd = -1, o_val = 1, flags;
 451
 452         fd = socket(a->ai_family, a->ai_socktype, a->ai_protocol);
 453         if (fd == -1)
 454                 return -1;
 455
 456         log_debug("%s: opened socket (%d) for %s", __func__,
 457             fd, a->ifname);
 458
 459         if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &o_val,
 460             sizeof(int)) == -1) {
 461                 log_warn("%s: setsockopt error", __func__);
 462                 close(fd);
 463                 return -1;
 464         }
 465
 466         /* non-blocking */
 467         flags = fcntl(fd, F_GETFL);
 468         flags |= O_NONBLOCK;
 469         if (fcntl(fd, F_SETFL, flags) == -1) {
 470                 log_warn("%s: could not enable non-blocking I/O", __func__);
 471                 close(fd);
 472                 return -1;
 473         }
 474
 475         if (bind(fd, (struct sockaddr *)&a->ss, a->slen) == -1) {
 476                 close(fd);
 477                 log_warn("%s: can't bind to port %d", __func__, a->port);
 478                 return -1;
 479         }
 480
 481         if (listen(fd, SOMAXCONN) == -1) {
 482                 log_warn("%s, unable to listen on socket", __func__);
 483                 close(fd);
 484                 return -1;
 485         }
 486
 487         return (fd);
 488 }
 489
 490 static int
 491 sockets_accept_reserve(int sockfd, struct sockaddr *addr, socklen_t *addrlen,
 492     int reserve, volatile int *counter)
 493 {
 494         int ret;
 495
 496         if (getdtablecount() + reserve +
 497             ((*counter + 1) * FD_NEEDED) >= getdtablesize()) {
 498                 log_warnx("inflight fds exceeded");
 499                 errno = EMFILE;
 500                 return -1;
 501         }
 502 /* TA:  This needs fixing upstream. */
 503 #ifdef __APPLE__
 504         ret = accept(sockfd, addr, addrlen);
 505 #else
 506         ret = accept4(sockfd, addr, addrlen, SOCK_NONBLOCK | SOCK_CLOEXEC);
 507 #endif
 508
 509         if (ret > -1) {
 510                 (*counter)++;
 511                 log_debug("inflight incremented, now %d", *counter);
 512         }
 513
 514         return ret;
 515 }
 516
 517 static void
 518 sockets_accept_paused(int fd, short events, void *arg)
 519 {
 520         struct socket *sock = (struct socket *)arg;
 521
 522         event_add(&sock->ev, NULL);
 523 }
 524
 525 void
 526 sockets_socket_accept(int fd, short event, void *arg)
 527 {
 528         struct socket *sock = (struct socket *)arg;
 529         struct sockaddr_storage ss;
 530         struct timeval backoff;
 531         struct request *c = NULL;
 532         socklen_t len;
 533         int s;
 534
 535         backoff.tv_sec = 1;
 536         backoff.tv_usec = 0;
 537
 538         event_add(&sock->ev, NULL);
 539         if (event & EV_TIMEOUT)
 540                 return;
 541
 542         len = sizeof(ss);
 543
 544         s = sockets_accept_reserve(fd, (struct sockaddr *)&ss, &len,
 545             FD_RESERVE, &cgi_inflight);
 546
 547         if (s == -1) {
 548                 switch (errno) {
 549                 case EINTR:
 550                 case EWOULDBLOCK:
 551                 case ECONNABORTED:
 552                         return;
 553                 case EMFILE:
 554                 case ENFILE:
 555                         event_del(&sock->ev);
 556                         evtimer_add(&sock->pause, &backoff);
 557                         return;
 558                 default:
 559                         log_warn("%s: accept", __func__);
 560                 }
 561         }
 562
 563         if (client_cnt > GOTWEBD_MAXCLIENTS)
 564                 goto err;
 565
 566         c = calloc(1, sizeof(struct request));
 567         if (c == NULL) {
 568                 log_warn("%s", __func__);
 569                 close(s);
 570                 cgi_inflight--;
 571                 return;
 572         }
 573
 574         c->tp = template(c, &fcgi_write, c->outbuf, sizeof(c->outbuf));
 575         if (c->tp == NULL) {
 576                 log_warn("%s", __func__);
 577                 close(s);
 578                 cgi_inflight--;
 579                 free(c);
 580                 return;
 581         }
 582
 583         c->fd = s;
 584         c->sock = sock;
 585         memcpy(c->priv_fd, gotwebd_env->priv_fd, sizeof(c->priv_fd));
 586         c->buf_pos = 0;
 587         c->buf_len = 0;
 588         c->request_started = 0;
 589         c->sock->client_status = CLIENT_CONNECT;
 590
 591         event_set(&c->ev, s, EV_READ|EV_PERSIST, fcgi_request, c);
 592         event_add(&c->ev, NULL);
 593
 594         evtimer_set(&c->tmo, fcgi_timeout, c);
 595         evtimer_add(&c->tmo, &timeout);
 596
 597         client_cnt++;
 598
 599         return;
 600 err:
 601         cgi_inflight--;
 602         close(s);
 603         if (c != NULL)
 604                 free(c);
 605 }
 606
 607 static void
 608 sockets_rlimit(int maxfd)
 609 {
 610         struct rlimit rl;
 611
 612         if (getrlimit(RLIMIT_NOFILE, &rl) == -1)
 613                 fatal("%s: failed to get resource limit", __func__);
 614         log_info("%s: max open files %llu", __func__,
 615             (unsigned long long)rl.rlim_max);
 616
 617         /*
 618          * Allow the maximum number of open file descriptors for this
 619          * login class (which should be the class "daemon" by default).
 620          */
 621         if (maxfd == -1)
 622                 rl.rlim_cur = rl.rlim_max;
 623         else
 624                 rl.rlim_cur = MAXIMUM(rl.rlim_max, (rlim_t)maxfd);
 625         if (setrlimit(RLIMIT_NOFILE, &rl) == -1)
 626                 fatal("%s: failed to set resource limit", __func__);
 627 }