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         struct event_base *evb;
  91
  92         evb = event_init();
  93
  94         sockets_rlimit(-1);
  95
  96         if ((env->iev_parent = malloc(sizeof(*env->iev_parent))) == NULL)
  97                 fatal("malloc");
  98         if (imsgbuf_init(&env->iev_parent->ibuf, fd) == -1)
  99                 fatal("imsgbuf_init");
 100         imsgbuf_allow_fdpass(&env->iev_parent->ibuf);
 101         env->iev_parent->handler = sockets_dispatch_main;
 102         env->iev_parent->data = env->iev_parent;
 103         event_set(&env->iev_parent->ev, fd, EV_READ, sockets_dispatch_main,
 104             env->iev_parent);
 105         event_add(&env->iev_parent->ev, NULL);
 106
 107         signal(SIGPIPE, SIG_IGN);
 108
 109         signal_set(&sighup, SIGHUP, sockets_sighdlr, env);
 110         signal_add(&sighup, NULL);
 111         signal_set(&sigint, SIGINT, sockets_sighdlr, env);
 112         signal_add(&sigint, NULL);
 113         signal_set(&sigusr1, SIGUSR1, sockets_sighdlr, env);
 114         signal_add(&sigusr1, NULL);
 115         signal_set(&sigchld, SIGCHLD, sockets_sighdlr, env);
 116         signal_add(&sigchld, NULL);
 117         signal_set(&sigterm, SIGTERM, sockets_sighdlr, env);
 118         signal_add(&sigterm, NULL);
 119
 120 #ifndef PROFILE
 121         if (pledge("stdio rpath inet recvfd proc exec sendfd unveil",
 122             NULL) == -1)
 123                 fatal("pledge");
 124 #endif
 125
 126         event_dispatch();
 127         event_base_free(evb);
 128         sockets_shutdown();
 129 }
 130
 131 void
 132 sockets_parse_sockets(struct gotwebd *env)
 133 {
 134         struct address *a;
 135         struct socket *new_sock = NULL;
 136         int sock_id = 1;
 137
 138         TAILQ_FOREACH(a, &env->addresses, entry) {
 139                 new_sock = sockets_conf_new_socket(env, sock_id, a);
 140                 if (new_sock) {
 141                         sock_id++;
 142                         TAILQ_INSERT_TAIL(&env->sockets,
 143                             new_sock, entry);
 144                 }
 145         }
 146 }
 147
 148 static struct socket *
 149 sockets_conf_new_socket(struct gotwebd *env, int id, struct address *a)
 150 {
 151         struct socket *sock;
 152         struct address *acp;
 153
 154         if ((sock = calloc(1, sizeof(*sock))) == NULL)
 155                 fatalx("%s: calloc", __func__);
 156
 157         sock->conf.id = id;
 158         sock->fd = -1;
 159         sock->conf.af_type = a->ss.ss_family;
 160
 161         if (a->ss.ss_family == AF_UNIX) {
 162                 struct sockaddr_un *sun;
 163
 164                 sun = (struct sockaddr_un *)&a->ss;
 165                 if (strlcpy(sock->conf.unix_socket_name, sun->sun_path,
 166                     sizeof(sock->conf.unix_socket_name)) >=
 167                     sizeof(sock->conf.unix_socket_name))
 168                         fatalx("unix socket path too long: %s", sun->sun_path);
 169         }
 170
 171         sock->conf.fcgi_socket_port = a->port;
 172
 173         acp = &sock->conf.addr;
 174
 175         memcpy(&acp->ss, &a->ss, sizeof(acp->ss));
 176         acp->slen = a->slen;
 177         acp->ai_family = a->ai_family;
 178         acp->ai_socktype = a->ai_socktype;
 179         acp->ai_protocol = a->ai_protocol;
 180         acp->port = a->port;
 181         if (*a->ifname != '\0') {
 182                 if (strlcpy(acp->ifname, a->ifname,
 183                     sizeof(acp->ifname)) >= sizeof(acp->ifname)) {
 184                         fatalx("%s: interface name truncated",
 185                             __func__);
 186                 }
 187         }
 188
 189         return (sock);
 190 }
 191
 192 static void
 193 sockets_launch(void)
 194 {
 195         struct socket *sock;
 196         struct server *srv;
 197         const struct got_error *error;
 198
 199         TAILQ_FOREACH(sock, &gotwebd_env->sockets, entry) {
 200                 log_info("%s: configuring socket %d (%d)", __func__,
 201                     sock->conf.id, sock->fd);
 202
 203                 event_set(&sock->ev, sock->fd, EV_READ | EV_PERSIST,
 204                     sockets_socket_accept, sock);
 205
 206                 if (event_add(&sock->ev, NULL))
 207                         fatalx("event add sock");
 208
 209                 evtimer_set(&sock->pause, sockets_accept_paused, sock);
 210
 211                 log_info("%s: running socket listener %d", __func__,
 212                     sock->conf.id);
 213         }
 214
 215         TAILQ_FOREACH(srv, &gotwebd_env->servers, entry) {
 216                 if (unveil(srv->repos_path, "r") == -1)
 217                         fatal("unveil %s", srv->repos_path);
 218         }
 219
 220         error = got_privsep_unveil_exec_helpers();
 221         if (error)
 222                 fatal("%s", error->msg);
 223
 224         if (unveil(NULL, NULL) == -1)
 225                 fatal("unveil");
 226 }
 227
 228 void
 229 sockets_purge(struct gotwebd *env)
 230 {
 231         struct socket *sock, *tsock;
 232
 233         /* shutdown and remove sockets */
 234         TAILQ_FOREACH_SAFE(sock, &env->sockets, entry, tsock) {
 235                 if (event_initialized(&sock->ev))
 236                         event_del(&sock->ev);
 237                 if (evtimer_initialized(&sock->evt))
 238                         evtimer_del(&sock->evt);
 239                 if (evtimer_initialized(&sock->pause))
 240                         evtimer_del(&sock->pause);
 241                 if (sock->fd != -1)
 242                         close(sock->fd);
 243                 TAILQ_REMOVE(&env->sockets, sock, entry);
 244                 free(sock);
 245         }
 246 }
 247
 248 static void
 249 sockets_dispatch_main(int fd, short event, void *arg)
 250 {
 251         struct imsgev           *iev = arg;
 252         struct imsgbuf          *ibuf;
 253         struct imsg              imsg;
 254         struct gotwebd          *env = gotwebd_env;
 255         ssize_t                  n;
 256         int                      shut = 0;
 257
 258         ibuf = &iev->ibuf;
 259
 260         if (event & EV_READ) {
 261                 if ((n = imsgbuf_read(ibuf)) == -1)
 262                         fatal("imsgbuf_read error");
 263                 if (n == 0)     /* Connection closed */
 264                         shut = 1;
 265         }
 266         if (event & EV_WRITE) {
 267                 if (imsgbuf_write(ibuf) == -1)
 268                         fatal("imsgbuf_write");
 269         }
 270
 271         for (;;) {
 272                 if ((n = imsg_get(ibuf, &imsg)) == -1)
 273                         fatal("imsg_get");
 274                 if (n == 0)     /* No more messages. */
 275                         break;
 276
 277                 switch (imsg.hdr.type) {
 278                 case IMSG_CFG_SRV:
 279                         config_getserver(env, &imsg);
 280                         break;
 281                 case IMSG_CFG_SOCK:
 282                         config_getsock(env, &imsg);
 283                         break;
 284                 case IMSG_CFG_FD:
 285                         config_getfd(env, &imsg);
 286                         break;
 287                 case IMSG_CFG_DONE:
 288                         config_getcfg(env, &imsg);
 289                         break;
 290                 case IMSG_CTL_START:
 291                         sockets_launch();
 292                         break;
 293                 default:
 294                         fatalx("%s: unknown imsg type %d", __func__,
 295                             imsg.hdr.type);
 296                 }
 297
 298                 imsg_free(&imsg);
 299         }
 300
 301         if (!shut)
 302                 imsg_event_add(iev);
 303         else {
 304                 /* This pipe is dead.  Remove its event handler */
 305                 event_del(&iev->ev);
 306                 event_loopexit(NULL);
 307         }
 308 }
 309
 310 static void
 311 sockets_sighdlr(int sig, short event, void *arg)
 312 {
 313         switch (sig) {
 314         case SIGHUP:
 315                 log_info("%s: ignoring SIGHUP", __func__);
 316                 break;
 317         case SIGPIPE:
 318                 log_info("%s: ignoring SIGPIPE", __func__);
 319                 break;
 320         case SIGUSR1:
 321                 log_info("%s: ignoring SIGUSR1", __func__);
 322                 break;
 323         case SIGCHLD:
 324                 break;
 325         case SIGINT:
 326         case SIGTERM:
 327                 sockets_shutdown();
 328                 break;
 329         default:
 330                 log_info("SIGNAL: %d", sig);
 331                 fatalx("unexpected signal");
 332         }
 333 }
 334
 335 static void
 336 sockets_shutdown(void)
 337 {
 338         sockets_purge(gotwebd_env);
 339
 340         /* clean servers */
 341         while (!TAILQ_EMPTY(&gotwebd_env->servers)) {
 342                 struct server *srv;
 343
 344                 srv = TAILQ_FIRST(&gotwebd_env->servers);
 345                 TAILQ_REMOVE(&gotwebd_env->servers, srv, entry);
 346                 free(srv);
 347         }
 348
 349         while (!TAILQ_EMPTY(&gotwebd_env->addresses)) {
 350                 struct address *h;
 351
 352                 h = TAILQ_FIRST(&gotwebd_env->addresses);
 353                 TAILQ_REMOVE(&gotwebd_env->addresses, h, entry);
 354                 free(h);
 355         }
 356
 357         imsgbuf_clear(&gotwebd_env->iev_parent->ibuf);
 358         free(gotwebd_env->iev_parent);
 359         free(gotwebd_env);
 360
 361         exit(0);
 362 }
 363
 364 int
 365 sockets_privinit(struct gotwebd *env, struct socket *sock)
 366 {
 367         if (sock->conf.af_type == AF_UNIX) {
 368                 log_info("%s: initializing unix socket %s", __func__,
 369                     sock->conf.unix_socket_name);
 370                 sock->fd = sockets_unix_socket_listen(env, sock);
 371                 if (sock->fd == -1)
 372                         return -1;
 373         }
 374
 375         if (sock->conf.af_type == AF_INET || sock->conf.af_type == AF_INET6) {
 376                 log_info("%s: initializing %s FCGI socket on port %d",
 377                     __func__, sock->conf.af_type == AF_INET ? "inet" : "inet6",
 378                     sock->conf.fcgi_socket_port);
 379                 sock->fd = sockets_create_socket(&sock->conf.addr);
 380                 if (sock->fd == -1)
 381                         return -1;
 382         }
 383
 384         return 0;
 385 }
 386
 387 static int
 388 sockets_unix_socket_listen(struct gotwebd *env, struct socket *sock)
 389 {
 390         int u_fd = -1;
 391         mode_t old_umask, mode;
 392         int flags = SOCK_STREAM | SOCK_NONBLOCK;
 393
 394 #ifdef SOCK_CLOEXEC
 395         flags |= SOCK_CLOEXEC;
 396 #endif
 397
 398         u_fd = socket(AF_UNIX, flags, 0);
 399         if (u_fd == -1) {
 400                 log_warn("%s: socket", __func__);
 401                 return -1;
 402         }
 403
 404         if (unlink(sock->conf.unix_socket_name) == -1) {
 405                 if (errno != ENOENT) {
 406                         log_warn("%s: unlink %s", __func__,
 407                             sock->conf.unix_socket_name);
 408                         close(u_fd);
 409                         return -1;
 410                 }
 411         }
 412
 413         old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
 414         mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP;
 415
 416         if (bind(u_fd, (struct sockaddr *)&sock->conf.addr.ss,
 417             sock->conf.addr.slen) == -1) {
 418                 log_warn("%s: bind: %s", __func__, sock->conf.unix_socket_name);
 419                 close(u_fd);
 420                 (void)umask(old_umask);
 421                 return -1;
 422         }
 423
 424         (void)umask(old_umask);
 425
 426         if (chmod(sock->conf.unix_socket_name, mode) == -1) {
 427                 log_warn("%s: chmod", __func__);
 428                 close(u_fd);
 429                 (void)unlink(sock->conf.unix_socket_name);
 430                 return -1;
 431         }
 432
 433         if (chown(sock->conf.unix_socket_name, env->pw->pw_uid,
 434             env->pw->pw_gid) == -1) {
 435                 log_warn("%s: chown", __func__);
 436                 close(u_fd);
 437                 (void)unlink(sock->conf.unix_socket_name);
 438                 return -1;
 439         }
 440
 441         if (listen(u_fd, SOCKS_BACKLOG) == -1) {
 442                 log_warn("%s: listen", __func__);
 443                 return -1;
 444         }
 445
 446         return u_fd;
 447 }
 448
 449 static int
 450 sockets_create_socket(struct address *a)
 451 {
 452         int fd = -1, o_val = 1, flags;
 453
 454         fd = socket(a->ai_family, a->ai_socktype, a->ai_protocol);
 455         if (fd == -1)
 456                 return -1;
 457
 458         log_debug("%s: opened socket (%d) for %s", __func__,
 459             fd, a->ifname);
 460
 461         if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &o_val,
 462             sizeof(int)) == -1) {
 463                 log_warn("%s: setsockopt error", __func__);
 464                 close(fd);
 465                 return -1;
 466         }
 467
 468         /* non-blocking */
 469         flags = fcntl(fd, F_GETFL);
 470         flags |= O_NONBLOCK;
 471         if (fcntl(fd, F_SETFL, flags) == -1) {
 472                 log_warn("%s: could not enable non-blocking I/O", __func__);
 473                 close(fd);
 474                 return -1;
 475         }
 476
 477         if (bind(fd, (struct sockaddr *)&a->ss, a->slen) == -1) {
 478                 close(fd);
 479                 log_warn("%s: can't bind to port %d", __func__, a->port);
 480                 return -1;
 481         }
 482
 483         if (listen(fd, SOMAXCONN) == -1) {
 484                 log_warn("%s, unable to listen on socket", __func__);
 485                 close(fd);
 486                 return -1;
 487         }
 488
 489         return (fd);
 490 }
 491
 492 static int
 493 sockets_accept_reserve(int sockfd, struct sockaddr *addr, socklen_t *addrlen,
 494     int reserve, volatile int *counter)
 495 {
 496         int ret;
 497
 498         if (getdtablecount() + reserve +
 499             ((*counter + 1) * FD_NEEDED) >= getdtablesize()) {
 500                 log_warnx("inflight fds exceeded");
 501                 errno = EMFILE;
 502                 return -1;
 503         }
 504 /* TA:  This needs fixing upstream. */
 505 #ifdef __APPLE__
 506         ret = accept(sockfd, addr, addrlen);
 507 #else
 508         ret = accept4(sockfd, addr, addrlen, SOCK_NONBLOCK | SOCK_CLOEXEC);
 509 #endif
 510
 511         if (ret > -1) {
 512                 (*counter)++;
 513                 log_debug("inflight incremented, now %d", *counter);
 514         }
 515
 516         return ret;
 517 }
 518
 519 static void
 520 sockets_accept_paused(int fd, short events, void *arg)
 521 {
 522         struct socket *sock = (struct socket *)arg;
 523
 524         event_add(&sock->ev, NULL);
 525 }
 526
 527 void
 528 sockets_socket_accept(int fd, short event, void *arg)
 529 {
 530         struct socket *sock = (struct socket *)arg;
 531         struct sockaddr_storage ss;
 532         struct timeval backoff;
 533         struct request *c = NULL;
 534         socklen_t len;
 535         int s;
 536
 537         backoff.tv_sec = 1;
 538         backoff.tv_usec = 0;
 539
 540         event_add(&sock->ev, NULL);
 541         if (event & EV_TIMEOUT)
 542                 return;
 543
 544         len = sizeof(ss);
 545
 546         s = sockets_accept_reserve(fd, (struct sockaddr *)&ss, &len,
 547             FD_RESERVE, &cgi_inflight);
 548
 549         if (s == -1) {
 550                 switch (errno) {
 551                 case EINTR:
 552                 case EWOULDBLOCK:
 553                 case ECONNABORTED:
 554                         return;
 555                 case EMFILE:
 556                 case ENFILE:
 557                         event_del(&sock->ev);
 558                         evtimer_add(&sock->pause, &backoff);
 559                         return;
 560                 default:
 561                         log_warn("%s: accept", __func__);
 562                 }
 563         }
 564
 565         if (client_cnt > GOTWEBD_MAXCLIENTS)
 566                 goto err;
 567
 568         c = calloc(1, sizeof(struct request));
 569         if (c == NULL) {
 570                 log_warn("%s", __func__);
 571                 close(s);
 572                 cgi_inflight--;
 573                 return;
 574         }
 575
 576         c->tp = template(c, &fcgi_write, c->outbuf, sizeof(c->outbuf));
 577         if (c->tp == NULL) {
 578                 log_warn("%s", __func__);
 579                 close(s);
 580                 cgi_inflight--;
 581                 free(c);
 582                 return;
 583         }
 584
 585         c->fd = s;
 586         c->sock = sock;
 587         memcpy(c->priv_fd, gotwebd_env->priv_fd, sizeof(c->priv_fd));
 588         c->buf_pos = 0;
 589         c->buf_len = 0;
 590         c->request_started = 0;
 591         c->sock->client_status = CLIENT_CONNECT;
 592
 593         event_set(&c->ev, s, EV_READ|EV_PERSIST, fcgi_request, c);
 594         event_add(&c->ev, NULL);
 595
 596         evtimer_set(&c->tmo, fcgi_timeout, c);
 597         evtimer_add(&c->tmo, &timeout);
 598
 599         client_cnt++;
 600
 601         return;
 602 err:
 603         cgi_inflight--;
 604         close(s);
 605         if (c != NULL)
 606                 free(c);
 607 }
 608
 609 static void
 610 sockets_rlimit(int maxfd)
 611 {
 612         struct rlimit rl;
 613
 614         if (getrlimit(RLIMIT_NOFILE, &rl) == -1)
 615                 fatal("%s: failed to get resource limit", __func__);
 616         log_info("%s: max open files %llu", __func__,
 617             (unsigned long long)rl.rlim_max);
 618
 619         /*
 620          * Allow the maximum number of open file descriptors for this
 621          * login class (which should be the class "daemon" by default).
 622          */
 623         if (maxfd == -1)
 624                 rl.rlim_cur = rl.rlim_max;
 625         else
 626                 rl.rlim_cur = MAXIMUM(rl.rlim_max, (rlim_t)maxfd);
 627         if (setrlimit(RLIMIT_NOFILE, &rl) == -1)
 628                 fatal("%s: failed to set resource limit", __func__);
 629 }