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