src/libsystemd-bus/bus-socket.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2013 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <endian.h>
  23 #include <assert.h>
  24 #include <stdlib.h>
  25 #include <unistd.h>
  26 #include <sys/poll.h>
  27 #include <byteswap.h>
  28
  29 #include "util.h"
  30 #include "macro.h"
  31 #include "missing.h"
  32 #include "strv.h"
  33 #include "utf8.h"
  34 #include "sd-daemon.h"
  35
  36 #include "sd-bus.h"
  37 #include "bus-socket.h"
  38 #include "bus-internal.h"
  39 #include "bus-message.h"
  40
  41 static void iovec_advance(struct iovec iov[], unsigned *idx, size_t size) {
  42
  43         while (size > 0) {
  44                 struct iovec *i = iov + *idx;
  45
  46                 if (i->iov_len > size) {
  47                         i->iov_base = (uint8_t*) i->iov_base + size;
  48                         i->iov_len -= size;
  49                         return;
  50                 }
  51
  52                 size -= i->iov_len;
  53
  54                 i->iov_base = NULL;
  55                 i->iov_len = 0;
  56
  57                 (*idx) ++;
  58         }
  59 }
  60
  61 bool bus_socket_auth_needs_write(sd_bus *b) {
  62
  63         unsigned i;
  64
  65         if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
  66                 return false;
  67
  68         for (i = b->auth_index; i < ELEMENTSOF(b->auth_iovec); i++) {
  69                 struct iovec *j = b->auth_iovec + i;
  70
  71                 if (j->iov_len > 0)
  72                         return true;
  73         }
  74
  75         return false;
  76 }
  77
  78 static int bus_socket_write_auth(sd_bus *b) {
  79         ssize_t k;
  80
  81         assert(b);
  82         assert(b->state == BUS_AUTHENTICATING);
  83
  84         if (!bus_socket_auth_needs_write(b))
  85                 return 0;
  86
  87         if (b->prefer_writev)
  88                 k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
  89         else {
  90                 struct msghdr mh;
  91                 zero(mh);
  92
  93                 mh.msg_iov = b->auth_iovec + b->auth_index;
  94                 mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
  95
  96                 k = sendmsg(b->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
  97                 if (k < 0 && errno == ENOTSOCK) {
  98                         b->prefer_writev = true;
  99                         k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
 100                 }
 101         }
 102
 103         if (k < 0)
 104                 return errno == EAGAIN ? 0 : -errno;
 105
 106         iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k);
 107         return 1;
 108 }
 109
 110 static int bus_socket_auth_verify_client(sd_bus *b) {
 111         char *e, *f, *start;
 112         sd_id128_t peer;
 113         unsigned i;
 114         int r;
 115
 116         assert(b);
 117
 118         /* We expect two response lines: "OK" and possibly
 119          * "AGREE_UNIX_FD" */
 120
 121         e = memmem(b->rbuffer, b->rbuffer_size, "\r\n", 2);
 122         if (!e)
 123                 return 0;
 124
 125         if (b->negotiate_fds) {
 126                 f = memmem(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2);
 127                 if (!f)
 128                         return 0;
 129
 130                 start = f + 2;
 131         } else {
 132                 f = NULL;
 133                 start = e + 2;
 134         }
 135
 136         /* Nice! We got all the lines we need. First check the OK
 137          * line */
 138
 139         if (e - (char*) b->rbuffer != 3 + 32)
 140                 return -EPERM;
 141
 142         if (memcmp(b->rbuffer, "OK ", 3))
 143                 return -EPERM;
 144
 145         b->auth = b->anonymous_auth ? BUS_AUTH_ANONYMOUS : BUS_AUTH_EXTERNAL;
 146
 147         for (i = 0; i < 32; i += 2) {
 148                 int x, y;
 149
 150                 x = unhexchar(((char*) b->rbuffer)[3 + i]);
 151                 y = unhexchar(((char*) b->rbuffer)[3 + i + 1]);
 152
 153                 if (x < 0 || y < 0)
 154                         return -EINVAL;
 155
 156                 peer.bytes[i/2] = ((uint8_t) x << 4 | (uint8_t) y);
 157         }
 158
 159         if (!sd_id128_equal(b->server_id, SD_ID128_NULL) &&
 160             !sd_id128_equal(b->server_id, peer))
 161                 return -EPERM;
 162
 163         b->server_id = peer;
 164
 165         /* And possibly check the second line, too */
 166
 167         if (f)
 168                 b->can_fds =
 169                         (f - e == sizeof("\r\nAGREE_UNIX_FD") - 1) &&
 170                         memcmp(e + 2, "AGREE_UNIX_FD", sizeof("AGREE_UNIX_FD") - 1) == 0;
 171
 172         b->rbuffer_size -= (start - (char*) b->rbuffer);
 173         memmove(b->rbuffer, start, b->rbuffer_size);
 174
 175         r = bus_start_running(b);
 176         if (r < 0)
 177                 return r;
 178
 179         return 1;
 180 }
 181
 182 static bool line_equals(const char *s, size_t m, const char *line) {
 183         size_t l;
 184
 185         l = strlen(line);
 186         if (l != m)
 187                 return false;
 188
 189         return memcmp(s, line, l) == 0;
 190 }
 191
 192 static bool line_begins(const char *s, size_t m, const char *word) {
 193         size_t l;
 194
 195         l = strlen(word);
 196         if (m < l)
 197                 return false;
 198
 199         if (memcmp(s, word, l) != 0)
 200                 return false;
 201
 202         return m == l || (m > l && s[l] == ' ');
 203 }
 204
 205 static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
 206         _cleanup_free_ char *token = NULL;
 207
 208         if (!b->anonymous_auth)
 209                 return 0;
 210
 211         if (l <= 0)
 212                 return 1;
 213
 214         assert(p[0] == ' ');
 215         p++; l--;
 216
 217         if (l % 2 != 0)
 218                 return 0;
 219         token = unhexmem(p, l);
 220         if (!token)
 221                 return -ENOMEM;
 222
 223         if (memchr(token, 0, l/2))
 224                 return 0;
 225
 226         return !!utf8_is_valid(token);
 227 }
 228
 229 static int verify_external_token(sd_bus *b, const char *p, size_t l) {
 230         _cleanup_free_ char *token = NULL;
 231         uid_t u;
 232         int r;
 233
 234         /* We don't do any real authentication here. Instead, we if
 235          * the owner of this bus wanted authentication he should have
 236          * checked SO_PEERCRED before even creating the bus object. */
 237
 238         if (!b->anonymous_auth && !b->ucred_valid)
 239                 return 0;
 240
 241         if (l <= 0)
 242                 return 1;
 243
 244         assert(p[0] == ' ');
 245         p++; l--;
 246
 247         if (l % 2 != 0)
 248                 return 0;
 249
 250         token = unhexmem(p, l);
 251         if (!token)
 252                 return -ENOMEM;
 253
 254         if (memchr(token, 0, l/2))
 255                 return 0;
 256
 257         r = parse_uid(token, &u);
 258         if (r < 0)
 259                 return 0;
 260
 261         /* We ignore the passed value if anonymous authentication is
 262          * on anyway. */
 263         if (!b->anonymous_auth && u != b->ucred.uid)
 264                 return 0;
 265
 266         return 1;
 267 }
 268
 269 static int bus_socket_auth_write(sd_bus *b, const char *t) {
 270         char *p;
 271         size_t l;
 272
 273         assert(b);
 274         assert(t);
 275
 276         /* We only make use of the first iovec */
 277         assert(b->auth_index == 0 || b->auth_index == 1);
 278
 279         l = strlen(t);
 280         p = malloc(b->auth_iovec[0].iov_len + l);
 281         if (!p)
 282                 return -ENOMEM;
 283
 284         memcpy(p, b->auth_iovec[0].iov_base, b->auth_iovec[0].iov_len);
 285         memcpy(p + b->auth_iovec[0].iov_len, t, l);
 286
 287         b->auth_iovec[0].iov_base = p;
 288         b->auth_iovec[0].iov_len += l;
 289
 290         free(b->auth_buffer);
 291         b->auth_buffer = p;
 292         b->auth_index = 0;
 293         return 0;
 294 }
 295
 296 static int bus_socket_auth_write_ok(sd_bus *b) {
 297         char t[3 + 32 + 2 + 1];
 298
 299         assert(b);
 300
 301         snprintf(t, sizeof(t), "OK " SD_ID128_FORMAT_STR "\r\n", SD_ID128_FORMAT_VAL(b->server_id));
 302         char_array_0(t);
 303
 304         return bus_socket_auth_write(b, t);
 305 }
 306
 307 static int bus_socket_auth_verify_server(sd_bus *b) {
 308         char *e;
 309         const char *line;
 310         size_t l;
 311         bool processed = false;
 312         int r;
 313
 314         assert(b);
 315
 316         if (b->rbuffer_size < 1)
 317                 return 0;
 318
 319         /* First char must be a NUL byte */
 320         if (*(char*) b->rbuffer != 0)
 321                 return -EIO;
 322
 323         if (b->rbuffer_size < 3)
 324                 return 0;
 325
 326         /* Begin with the first line */
 327         if (b->auth_rbegin <= 0)
 328                 b->auth_rbegin = 1;
 329
 330         for (;;) {
 331                 /* Check if line is complete */
 332                 line = (char*) b->rbuffer + b->auth_rbegin;
 333                 e = memmem(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2);
 334                 if (!e)
 335                         return processed;
 336
 337                 l = e - line;
 338
 339                 if (line_begins(line, l, "AUTH ANONYMOUS")) {
 340
 341                         r = verify_anonymous_token(b, line + 14, l - 14);
 342                         if (r < 0)
 343                                 return r;
 344                         if (r == 0)
 345                                 r = bus_socket_auth_write(b, "REJECTED\r\n");
 346                         else {
 347                                 b->auth = BUS_AUTH_ANONYMOUS;
 348                                 r = bus_socket_auth_write_ok(b);
 349                         }
 350
 351                 } else if (line_begins(line, l, "AUTH EXTERNAL")) {
 352
 353                         r = verify_external_token(b, line + 13, l - 13);
 354                         if (r < 0)
 355                                 return r;
 356                         if (r == 0)
 357                                 r = bus_socket_auth_write(b, "REJECTED\r\n");
 358                         else {
 359                                 b->auth = BUS_AUTH_EXTERNAL;
 360                                 r = bus_socket_auth_write_ok(b);
 361                         }
 362
 363                 } else if (line_begins(line, l, "AUTH"))
 364                         r = bus_socket_auth_write(b, "REJECTED EXTERNAL ANONYMOUS\r\n");
 365                 else if (line_equals(line, l, "CANCEL") ||
 366                          line_begins(line, l, "ERROR")) {
 367
 368                         b->auth = _BUS_AUTH_INVALID;
 369                         r = bus_socket_auth_write(b, "REJECTED\r\n");
 370
 371                 } else if (line_equals(line, l, "BEGIN")) {
 372
 373                         if (b->auth == _BUS_AUTH_INVALID)
 374                                 r = bus_socket_auth_write(b, "ERROR\r\n");
 375                         else {
 376                                 /* We can't leave from the auth phase
 377                                  * before we haven't written
 378                                  * everything queued, so let's check
 379                                  * that */
 380
 381                                 if (bus_socket_auth_needs_write(b))
 382                                         return 1;
 383
 384                                 b->rbuffer_size -= (e + 2 - (char*) b->rbuffer);
 385                                 memmove(b->rbuffer, e + 2, b->rbuffer_size);
 386                                 return bus_start_running(b);
 387                         }
 388
 389                 } else if (line_begins(line, l, "DATA")) {
 390
 391                         if (b->auth == _BUS_AUTH_INVALID)
 392                                 r = bus_socket_auth_write(b, "ERROR\r\n");
 393                         else {
 394                                 if (b->auth == BUS_AUTH_ANONYMOUS)
 395                                         r = verify_anonymous_token(b, line + 4, l - 4);
 396                                 else
 397                                         r = verify_external_token(b, line + 4, l - 4);
 398
 399                                 if (r < 0)
 400                                         return r;
 401                                 if (r == 0) {
 402                                         b->auth = _BUS_AUTH_INVALID;
 403                                         r = bus_socket_auth_write(b, "REJECTED\r\n");
 404                                 } else
 405                                         r = bus_socket_auth_write_ok(b);
 406                         }
 407                 } else if (line_equals(line, l, "NEGOTIATE_UNIX_FD")) {
 408                         if (b->auth == _BUS_AUTH_INVALID || !b->negotiate_fds)
 409                                 r = bus_socket_auth_write(b, "ERROR\r\n");
 410                         else {
 411                                 b->can_fds = true;
 412                                 r = bus_socket_auth_write(b, "AGREE_UNIX_FD\r\n");
 413                         }
 414                 } else
 415                         r = bus_socket_auth_write(b, "ERROR\r\n");
 416
 417                 if (r < 0)
 418                         return r;
 419
 420                 b->auth_rbegin = e + 2 - (char*) b->rbuffer;
 421
 422                 processed = true;
 423         }
 424 }
 425
 426 static int bus_socket_auth_verify(sd_bus *b) {
 427         assert(b);
 428
 429         if (b->is_server)
 430                 return bus_socket_auth_verify_server(b);
 431         else
 432                 return bus_socket_auth_verify_client(b);
 433 }
 434
 435 static int bus_socket_read_auth(sd_bus *b) {
 436         struct msghdr mh;
 437         struct iovec iov;
 438         size_t n;
 439         ssize_t k;
 440         int r;
 441         void *p;
 442         union {
 443                 struct cmsghdr cmsghdr;
 444                 uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
 445                             CMSG_SPACE(sizeof(struct ucred)) +
 446                             CMSG_SPACE(NAME_MAX)]; /*selinux label */
 447         } control;
 448         struct cmsghdr *cmsg;
 449         bool handle_cmsg = false;
 450
 451         assert(b);
 452         assert(b->state == BUS_AUTHENTICATING);
 453
 454         r = bus_socket_auth_verify(b);
 455         if (r != 0)
 456                 return r;
 457
 458         n = MAX(256u, b->rbuffer_size * 2);
 459
 460         if (n > BUS_AUTH_SIZE_MAX)
 461                 n = BUS_AUTH_SIZE_MAX;
 462
 463         if (b->rbuffer_size >= n)
 464                 return -ENOBUFS;
 465
 466         p = realloc(b->rbuffer, n);
 467         if (!p)
 468                 return -ENOMEM;
 469
 470         b->rbuffer = p;
 471
 472         zero(iov);
 473         iov.iov_base = (uint8_t*) b->rbuffer + b->rbuffer_size;
 474         iov.iov_len = n - b->rbuffer_size;
 475
 476         if (b->prefer_readv)
 477                 k = readv(b->input_fd, &iov, 1);
 478         else {
 479                 zero(mh);
 480                 mh.msg_iov = &iov;
 481                 mh.msg_iovlen = 1;
 482                 mh.msg_control = &control;
 483                 mh.msg_controllen = sizeof(control);
 484
 485                 k = recvmsg(b->input_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
 486                 if (k < 0 && errno == ENOTSOCK) {
 487                         b->prefer_readv = true;
 488                         k = readv(b->input_fd, &iov, 1);
 489                 } else
 490                         handle_cmsg = true;
 491         }
 492         if (k < 0)
 493                 return errno == EAGAIN ? 0 : -errno;
 494         if (k == 0)
 495                 return -ECONNRESET;
 496
 497         b->rbuffer_size += k;
 498
 499         if (handle_cmsg) {
 500                 for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
 501                         if (cmsg->cmsg_level == SOL_SOCKET &&
 502                             cmsg->cmsg_type == SCM_RIGHTS) {
 503                                 int j;
 504
 505                                 /* Whut? We received fds during the auth
 506                                  * protocol? Somebody is playing games with
 507                                  * us. Close them all, and fail */
 508                                 j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
 509                                 close_many((int*) CMSG_DATA(cmsg), j);
 510                                 return -EIO;
 511
 512                         } else if (cmsg->cmsg_level == SOL_SOCKET &&
 513                                    cmsg->cmsg_type == SCM_CREDENTIALS &&
 514                                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
 515
 516                                 /* Ignore bogus data, which we might
 517                                  * get on socketpair() sockets */
 518                                 if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) {
 519                                         memcpy(&b->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
 520                                         b->ucred_valid = true;
 521                                 }
 522
 523                         } else if (cmsg->cmsg_level == SOL_SOCKET &&
 524                                    cmsg->cmsg_type == SCM_SECURITY) {
 525
 526                                 size_t l;
 527
 528                                 l = cmsg->cmsg_len - CMSG_LEN(0);
 529                                 if (l > 0) {
 530                                         memcpy(&b->label, CMSG_DATA(cmsg), l);
 531                                         b->label[l] = 0;
 532                                 }
 533                         }
 534                 }
 535         }
 536
 537         r = bus_socket_auth_verify(b);
 538         if (r != 0)
 539                 return r;
 540
 541         return 1;
 542 }
 543
 544 static int bus_socket_setup(sd_bus *b) {
 545         int enable;
 546         socklen_t l;
 547
 548         assert(b);
 549
 550         /* Enable SO_PASSCRED + SO_PASSEC. We try this on any
 551          * socket, just in case. */
 552         enable = !b->bus_client;
 553         setsockopt(b->input_fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable));
 554         setsockopt(b->input_fd, SOL_SOCKET, SO_PASSSEC, &enable, sizeof(enable));
 555
 556         /* Increase the buffers to a MB */
 557         fd_inc_rcvbuf(b->input_fd, 1024*1024);
 558         fd_inc_sndbuf(b->output_fd, 1024*1024);
 559
 560         /* Get the peer for socketpair() sockets */
 561         l = sizeof(b->ucred);
 562         if (getsockopt(b->input_fd, SOL_SOCKET, SO_PEERCRED, &b->ucred, &l) >= 0 && l >= sizeof(b->ucred))
 563                 b->ucred_valid = b->ucred.pid > 0;
 564
 565         return 0;
 566 }
 567
 568 static int bus_socket_start_auth_client(sd_bus *b) {
 569         size_t l;
 570         const char *auth_suffix, *auth_prefix;
 571
 572         assert(b);
 573
 574         if (b->anonymous_auth) {
 575                 auth_prefix = "\0AUTH ANONYMOUS ";
 576
 577                 /* For ANONYMOUS auth we send some arbitrary "trace" string */
 578                 l = 9;
 579                 b->auth_buffer = hexmem("anonymous", l);
 580         } else {
 581                 char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
 582
 583                 auth_prefix = "\0AUTH EXTERNAL ";
 584
 585                 snprintf(text, sizeof(text), "%lu", (unsigned long) geteuid());
 586                 char_array_0(text);
 587
 588                 l = strlen(text);
 589                 b->auth_buffer = hexmem(text, l);
 590         }
 591
 592         if (!b->auth_buffer)
 593                 return -ENOMEM;
 594
 595         if (b->negotiate_fds)
 596                 auth_suffix = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
 597         else
 598                 auth_suffix = "\r\nBEGIN\r\n";
 599
 600         b->auth_iovec[0].iov_base = (void*) auth_prefix;
 601         b->auth_iovec[0].iov_len = 1 + strlen(auth_prefix + 1);
 602         b->auth_iovec[1].iov_base = (void*) b->auth_buffer;
 603         b->auth_iovec[1].iov_len = l * 2;
 604         b->auth_iovec[2].iov_base = (void*) auth_suffix;
 605         b->auth_iovec[2].iov_len = strlen(auth_suffix);
 606
 607         return bus_socket_write_auth(b);
 608 }
 609
 610 static int bus_socket_start_auth(sd_bus *b) {
 611         assert(b);
 612
 613         b->state = BUS_AUTHENTICATING;
 614         b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_DEFAULT_TIMEOUT;
 615
 616         if (sd_is_socket(b->input_fd, AF_UNIX, 0, 0) <= 0)
 617                 b->negotiate_fds = false;
 618
 619         if (b->output_fd != b->input_fd)
 620                 if (sd_is_socket(b->output_fd, AF_UNIX, 0, 0) <= 0)
 621                         b->negotiate_fds = false;
 622
 623         if (b->is_server)
 624                 return bus_socket_read_auth(b);
 625         else
 626                 return bus_socket_start_auth_client(b);
 627 }
 628
 629 int bus_socket_connect(sd_bus *b) {
 630         int r;
 631
 632         assert(b);
 633         assert(b->input_fd < 0);
 634         assert(b->output_fd < 0);
 635         assert(b->sockaddr.sa.sa_family != AF_UNSPEC);
 636
 637         b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 638         if (b->input_fd < 0)
 639                 return -errno;
 640
 641         b->output_fd = b->input_fd;
 642
 643         r = bus_socket_setup(b);
 644         if (r < 0)
 645                 return r;
 646
 647         r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
 648         if (r < 0) {
 649                 if (errno == EINPROGRESS)
 650                         return 1;
 651
 652                 return -errno;
 653         }
 654
 655         return bus_socket_start_auth(b);
 656 }
 657
 658 int bus_socket_exec(sd_bus *b) {
 659         int s[2], r;
 660         pid_t pid;
 661
 662         assert(b);
 663         assert(b->input_fd < 0);
 664         assert(b->output_fd < 0);
 665         assert(b->exec_path);
 666
 667         r = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s);
 668         if (r < 0)
 669                 return -errno;
 670
 671         pid = fork();
 672         if (pid < 0) {
 673                 close_pipe(s);
 674                 return -errno;
 675         }
 676         if (pid == 0) {
 677                 /* Child */
 678
 679                 reset_all_signal_handlers();
 680
 681                 close_all_fds(s+1, 1);
 682
 683                 assert_se(dup3(s[1], STDIN_FILENO, 0) == STDIN_FILENO);
 684                 assert_se(dup3(s[1], STDOUT_FILENO, 0) == STDOUT_FILENO);
 685
 686                 if (s[1] != STDIN_FILENO && s[1] != STDOUT_FILENO)
 687                         close_nointr_nofail(s[1]);
 688
 689                 fd_cloexec(STDIN_FILENO, false);
 690                 fd_cloexec(STDOUT_FILENO, false);
 691                 fd_nonblock(STDIN_FILENO, false);
 692                 fd_nonblock(STDOUT_FILENO, false);
 693
 694                 if (b->exec_argv)
 695                         execvp(b->exec_path, b->exec_argv);
 696                 else {
 697                         const char *argv[] = { b->exec_path, NULL };
 698                         execvp(b->exec_path, (char**) argv);
 699                 }
 700
 701                 _exit(EXIT_FAILURE);
 702         }
 703
 704         close_nointr_nofail(s[1]);
 705         b->output_fd = b->input_fd = s[0];
 706
 707         return bus_socket_start_auth(b);
 708 }
 709
 710 int bus_socket_take_fd(sd_bus *b) {
 711         int  r;
 712         assert(b);
 713
 714         r = bus_socket_setup(b);
 715         if (r < 0)
 716                 return r;
 717
 718         return bus_socket_start_auth(b);
 719 }
 720
 721 int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) {
 722         struct iovec *iov;
 723         ssize_t k;
 724         size_t n;
 725         unsigned j;
 726
 727         assert(bus);
 728         assert(m);
 729         assert(idx);
 730         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 731
 732         if (*idx >= m->size)
 733                 return 0;
 734
 735         n = m->n_iovec * sizeof(struct iovec);
 736         iov = alloca(n);
 737         memcpy(iov, m->iovec, n);
 738
 739         j = 0;
 740         iovec_advance(iov, &j, *idx);
 741
 742         if (bus->prefer_writev)
 743                 k = writev(bus->output_fd, iov, m->n_iovec);
 744         else {
 745                 struct msghdr mh;
 746                 zero(mh);
 747
 748                 if (m->n_fds > 0) {
 749                         struct cmsghdr *control;
 750                         control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds));
 751
 752                         mh.msg_control = control;
 753                         control->cmsg_level = SOL_SOCKET;
 754                         control->cmsg_type = SCM_RIGHTS;
 755                         mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds);
 756                         memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds);
 757                 }
 758
 759                 mh.msg_iov = iov;
 760                 mh.msg_iovlen = m->n_iovec;
 761
 762                 k = sendmsg(bus->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
 763                 if (k < 0 && errno == ENOTSOCK) {
 764                         bus->prefer_writev = true;
 765                         k = writev(bus->output_fd, iov, m->n_iovec);
 766                 }
 767         }
 768
 769         if (k < 0)
 770                 return errno == EAGAIN ? 0 : -errno;
 771
 772         *idx += (size_t) k;
 773         return 1;
 774 }
 775
 776 static int bus_socket_read_message_need(sd_bus *bus, size_t *need) {
 777         uint32_t a, b;
 778         uint8_t e;
 779         uint64_t sum;
 780
 781         assert(bus);
 782         assert(need);
 783         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 784
 785         if (bus->rbuffer_size < sizeof(struct bus_header)) {
 786                 *need = sizeof(struct bus_header) + 8;
 787
 788                 /* Minimum message size:
 789                  *
 790                  * Header +
 791                  *
 792                  *  Method Call: +2 string headers
 793                  *       Signal: +3 string headers
 794                  * Method Error: +1 string headers
 795                  *               +1 uint32 headers
 796                  * Method Reply: +1 uint32 headers
 797                  *
 798                  * A string header is at least 9 bytes
 799                  * A uint32 header is at least 8 bytes
 800                  *
 801                  * Hence the minimum message size of a valid message
 802                  * is header + 8 bytes */
 803
 804                 return 0;
 805         }
 806
 807         a = ((const uint32_t*) bus->rbuffer)[1];
 808         b = ((const uint32_t*) bus->rbuffer)[3];
 809
 810         e = ((const uint8_t*) bus->rbuffer)[0];
 811         if (e == SD_BUS_LITTLE_ENDIAN) {
 812                 a = le32toh(a);
 813                 b = le32toh(b);
 814         } else if (e == SD_BUS_BIG_ENDIAN) {
 815                 a = be32toh(a);
 816                 b = be32toh(b);
 817         } else
 818                 return -EBADMSG;
 819
 820         sum = (uint64_t) sizeof(struct bus_header) + (uint64_t) ALIGN_TO(b, 8) + (uint64_t) a;
 821         if (sum >= BUS_MESSAGE_SIZE_MAX)
 822                 return -ENOBUFS;
 823
 824         *need = (size_t) sum;
 825         return 0;
 826 }
 827
 828 static int bus_socket_make_message(sd_bus *bus, size_t size, sd_bus_message **m) {
 829         sd_bus_message *t;
 830         void *b;
 831         int r;
 832
 833         assert(bus);
 834         assert(m);
 835         assert(bus->rbuffer_size >= size);
 836         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 837
 838         if (bus->rbuffer_size > size) {
 839                 b = memdup((const uint8_t*) bus->rbuffer + size,
 840                            bus->rbuffer_size - size);
 841                 if (!b)
 842                         return -ENOMEM;
 843         } else
 844                 b = NULL;
 845
 846         r = bus_message_from_malloc(bus->rbuffer, size,
 847                                     bus->fds, bus->n_fds,
 848                                     bus->ucred_valid ? &bus->ucred : NULL,
 849                                     bus->label[0] ? bus->label : NULL,
 850                                     &t);
 851         if (r < 0) {
 852                 free(b);
 853                 return r;
 854         }
 855
 856         bus->rbuffer = b;
 857         bus->rbuffer_size -= size;
 858
 859         bus->fds = NULL;
 860         bus->n_fds = 0;
 861
 862         *m = t;
 863         return 1;
 864 }
 865
 866 int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
 867         struct msghdr mh;
 868         struct iovec iov;
 869         ssize_t k;
 870         size_t need;
 871         int r;
 872         void *b;
 873         union {
 874                 struct cmsghdr cmsghdr;
 875                 uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
 876                             CMSG_SPACE(sizeof(struct ucred)) +
 877                             CMSG_SPACE(NAME_MAX)]; /*selinux label */
 878         } control;
 879         struct cmsghdr *cmsg;
 880         bool handle_cmsg;
 881
 882         assert(bus);
 883         assert(m);
 884         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 885
 886         r = bus_socket_read_message_need(bus, &need);
 887         if (r < 0)
 888                 return r;
 889
 890         if (bus->rbuffer_size >= need)
 891                 return bus_socket_make_message(bus, need, m);
 892
 893         b = realloc(bus->rbuffer, need);
 894         if (!b)
 895                 return -ENOMEM;
 896
 897         bus->rbuffer = b;
 898
 899         zero(iov);
 900         iov.iov_base = (uint8_t*) bus->rbuffer + bus->rbuffer_size;
 901         iov.iov_len = need - bus->rbuffer_size;
 902
 903         if (bus->prefer_readv)
 904                 k = readv(bus->input_fd, &iov, 1);
 905         else {
 906                 zero(mh);
 907                 mh.msg_iov = &iov;
 908                 mh.msg_iovlen = 1;
 909                 mh.msg_control = &control;
 910                 mh.msg_controllen = sizeof(control);
 911
 912                 k = recvmsg(bus->input_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
 913                 if (k < 0 && errno == ENOTSOCK) {
 914                         bus->prefer_readv = true;
 915                         k = readv(bus->input_fd, &iov, 1);
 916                 } else
 917                         handle_cmsg = true;
 918         }
 919         if (k < 0)
 920                 return errno == EAGAIN ? 0 : -errno;
 921         if (k == 0)
 922                 return -ECONNRESET;
 923
 924         bus->rbuffer_size += k;
 925
 926         if (handle_cmsg) {
 927                 for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
 928                         if (cmsg->cmsg_level == SOL_SOCKET &&
 929                             cmsg->cmsg_type == SCM_RIGHTS) {
 930                                 int n, *f;
 931
 932                                 n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
 933
 934                                 if (!bus->can_fds) {
 935                                         /* Whut? We received fds but this
 936                                          * isn't actually enabled? Close them,
 937                                          * and fail */
 938
 939                                         close_many((int*) CMSG_DATA(cmsg), n);
 940                                         return -EIO;
 941                                 }
 942
 943                                 f = realloc(bus->fds, sizeof(int) + (bus->n_fds + n));
 944                                 if (!f) {
 945                                         close_many((int*) CMSG_DATA(cmsg), n);
 946                                         return -ENOMEM;
 947                                 }
 948
 949                                 memcpy(f + bus->n_fds, CMSG_DATA(cmsg), n * sizeof(int));
 950                                 bus->fds = f;
 951                                 bus->n_fds += n;
 952                         } else if (cmsg->cmsg_level == SOL_SOCKET &&
 953                                    cmsg->cmsg_type == SCM_CREDENTIALS &&
 954                                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
 955
 956                                 /* Ignore bogus data, which we might
 957                                  * get on socketpair() sockets */
 958                                 if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) {
 959                                         memcpy(&bus->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
 960                                         bus->ucred_valid = true;
 961                                 }
 962
 963                         } else if (cmsg->cmsg_level == SOL_SOCKET &&
 964                                    cmsg->cmsg_type == SCM_SECURITY) {
 965
 966                                 size_t l;
 967                                 l = cmsg->cmsg_len - CMSG_LEN(0);
 968                                 if (l > 0) {
 969                                         memcpy(&bus->label, CMSG_DATA(cmsg), l);
 970                                         bus->label[l] = 0;
 971                                 }
 972                         }
 973                 }
 974         }
 975
 976         r = bus_socket_read_message_need(bus, &need);
 977         if (r < 0)
 978                 return r;
 979
 980         if (bus->rbuffer_size >= need)
 981                 return bus_socket_make_message(bus, need, m);
 982
 983         return 1;
 984 }
 985
 986 int bus_socket_process_opening(sd_bus *b) {
 987         int error = 0;
 988         socklen_t slen = sizeof(error);
 989         struct pollfd p = {
 990                 .fd = b->output_fd,
 991                 .events = POLLOUT,
 992         };
 993         int r;
 994
 995         assert(b->state == BUS_OPENING);
 996
 997         r = poll(&p, 1, 0);
 998         if (r < 0)
 999                 return -errno;
1000
1001         if (!(p.revents & (POLLOUT|POLLERR|POLLHUP)))
1002                 return 0;
1003
1004         r = getsockopt(b->output_fd, SOL_SOCKET, SO_ERROR, &error, &slen);
1005         if (r < 0)
1006                 b->last_connect_error = errno;
1007         else if (error != 0)
1008                 b->last_connect_error = error;
1009         else if (p.revents & (POLLERR|POLLHUP))
1010                 b->last_connect_error = ECONNREFUSED;
1011         else
1012                 return bus_socket_start_auth(b);
1013
1014         return bus_next_address(b);
1015 }
1016
1017 int bus_socket_process_authenticating(sd_bus *b) {
1018         int r;
1019
1020         assert(b);
1021         assert(b->state == BUS_AUTHENTICATING);
1022
1023         if (now(CLOCK_MONOTONIC) >= b->auth_timeout)
1024                 return -ETIMEDOUT;
1025
1026         r = bus_socket_write_auth(b);
1027         if (r != 0)
1028                 return r;
1029
1030         return bus_socket_read_auth(b);
1031 }