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 static int append_iovec(sd_bus_message *m, const void *p, size_t sz) {
  62         assert(m);
  63         assert(p);
  64         assert(sz > 0);
  65
  66         m->iovec[m->n_iovec].iov_base = (void*) p;
  67         m->iovec[m->n_iovec].iov_len = sz;
  68         m->n_iovec++;
  69
  70         return 0;
  71 }
  72
  73 static int bus_message_setup_iovec(sd_bus_message *m) {
  74         struct bus_body_part *part;
  75         unsigned n, i;
  76         int r;
  77
  78         assert(m);
  79         assert(m->sealed);
  80
  81         if (m->n_iovec > 0)
  82                 return 0;
  83
  84         assert(!m->iovec);
  85
  86         n = 1 + m->n_body_parts;
  87         if (n < ELEMENTSOF(m->iovec_fixed))
  88                 m->iovec = m->iovec_fixed;
  89         else {
  90                 m->iovec = new(struct iovec, n);
  91                 if (!m->iovec) {
  92                         r = -ENOMEM;
  93                         goto fail;
  94                 }
  95         }
  96
  97         r = append_iovec(m, m->header, BUS_MESSAGE_BODY_BEGIN(m));
  98         if (r < 0)
  99                 goto fail;
 100
 101         MESSAGE_FOREACH_PART(part, i, m)  {
 102                 r = bus_body_part_map(part);
 103                 if (r < 0)
 104                         goto fail;
 105
 106                 r = append_iovec(m, part->data, part->size);
 107                 if (r < 0)
 108                         goto fail;
 109         }
 110
 111         assert(n == m->n_iovec);
 112
 113         return 0;
 114
 115 fail:
 116         m->poisoned = true;
 117         return r;
 118 }
 119
 120 bool bus_socket_auth_needs_write(sd_bus *b) {
 121
 122         unsigned i;
 123
 124         if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
 125                 return false;
 126
 127         for (i = b->auth_index; i < ELEMENTSOF(b->auth_iovec); i++) {
 128                 struct iovec *j = b->auth_iovec + i;
 129
 130                 if (j->iov_len > 0)
 131                         return true;
 132         }
 133
 134         return false;
 135 }
 136
 137 static int bus_socket_write_auth(sd_bus *b) {
 138         ssize_t k;
 139
 140         assert(b);
 141         assert(b->state == BUS_AUTHENTICATING);
 142
 143         if (!bus_socket_auth_needs_write(b))
 144                 return 0;
 145
 146         if (b->prefer_writev)
 147                 k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
 148         else {
 149                 struct msghdr mh;
 150                 zero(mh);
 151
 152                 mh.msg_iov = b->auth_iovec + b->auth_index;
 153                 mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
 154
 155                 k = sendmsg(b->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
 156                 if (k < 0 && errno == ENOTSOCK) {
 157                         b->prefer_writev = true;
 158                         k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
 159                 }
 160         }
 161
 162         if (k < 0)
 163                 return errno == EAGAIN ? 0 : -errno;
 164
 165         iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k);
 166         return 1;
 167 }
 168
 169 static int bus_socket_auth_verify_client(sd_bus *b) {
 170         char *e, *f, *start;
 171         sd_id128_t peer;
 172         unsigned i;
 173         int r;
 174
 175         assert(b);
 176
 177         /* We expect two response lines: "OK" and possibly
 178          * "AGREE_UNIX_FD" */
 179
 180         e = memmem(b->rbuffer, b->rbuffer_size, "\r\n", 2);
 181         if (!e)
 182                 return 0;
 183
 184         if (b->hello_flags & KDBUS_HELLO_ACCEPT_FD) {
 185                 f = memmem(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2);
 186                 if (!f)
 187                         return 0;
 188
 189                 start = f + 2;
 190         } else {
 191                 f = NULL;
 192                 start = e + 2;
 193         }
 194
 195         /* Nice! We got all the lines we need. First check the OK
 196          * line */
 197
 198         if (e - (char*) b->rbuffer != 3 + 32)
 199                 return -EPERM;
 200
 201         if (memcmp(b->rbuffer, "OK ", 3))
 202                 return -EPERM;
 203
 204         b->auth = b->anonymous_auth ? BUS_AUTH_ANONYMOUS : BUS_AUTH_EXTERNAL;
 205
 206         for (i = 0; i < 32; i += 2) {
 207                 int x, y;
 208
 209                 x = unhexchar(((char*) b->rbuffer)[3 + i]);
 210                 y = unhexchar(((char*) b->rbuffer)[3 + i + 1]);
 211
 212                 if (x < 0 || y < 0)
 213                         return -EINVAL;
 214
 215                 peer.bytes[i/2] = ((uint8_t) x << 4 | (uint8_t) y);
 216         }
 217
 218         if (!sd_id128_equal(b->server_id, SD_ID128_NULL) &&
 219             !sd_id128_equal(b->server_id, peer))
 220                 return -EPERM;
 221
 222         b->server_id = peer;
 223
 224         /* And possibly check the second line, too */
 225
 226         if (f)
 227                 b->can_fds =
 228                         (f - e == sizeof("\r\nAGREE_UNIX_FD") - 1) &&
 229                         memcmp(e + 2, "AGREE_UNIX_FD", sizeof("AGREE_UNIX_FD") - 1) == 0;
 230
 231         b->rbuffer_size -= (start - (char*) b->rbuffer);
 232         memmove(b->rbuffer, start, b->rbuffer_size);
 233
 234         r = bus_start_running(b);
 235         if (r < 0)
 236                 return r;
 237
 238         return 1;
 239 }
 240
 241 static bool line_equals(const char *s, size_t m, const char *line) {
 242         size_t l;
 243
 244         l = strlen(line);
 245         if (l != m)
 246                 return false;
 247
 248         return memcmp(s, line, l) == 0;
 249 }
 250
 251 static bool line_begins(const char *s, size_t m, const char *word) {
 252         size_t l;
 253
 254         l = strlen(word);
 255         if (m < l)
 256                 return false;
 257
 258         if (memcmp(s, word, l) != 0)
 259                 return false;
 260
 261         return m == l || (m > l && s[l] == ' ');
 262 }
 263
 264 static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
 265         _cleanup_free_ char *token = NULL;
 266
 267         if (!b->anonymous_auth)
 268                 return 0;
 269
 270         if (l <= 0)
 271                 return 1;
 272
 273         assert(p[0] == ' ');
 274         p++; l--;
 275
 276         if (l % 2 != 0)
 277                 return 0;
 278         token = unhexmem(p, l);
 279         if (!token)
 280                 return -ENOMEM;
 281
 282         if (memchr(token, 0, l/2))
 283                 return 0;
 284
 285         return !!utf8_is_valid(token);
 286 }
 287
 288 static int verify_external_token(sd_bus *b, const char *p, size_t l) {
 289         _cleanup_free_ char *token = NULL;
 290         uid_t u;
 291         int r;
 292
 293         /* We don't do any real authentication here. Instead, we if
 294          * the owner of this bus wanted authentication he should have
 295          * checked SO_PEERCRED before even creating the bus object. */
 296
 297         if (!b->anonymous_auth && !b->ucred_valid)
 298                 return 0;
 299
 300         if (l <= 0)
 301                 return 1;
 302
 303         assert(p[0] == ' ');
 304         p++; l--;
 305
 306         if (l % 2 != 0)
 307                 return 0;
 308
 309         token = unhexmem(p, l);
 310         if (!token)
 311                 return -ENOMEM;
 312
 313         if (memchr(token, 0, l/2))
 314                 return 0;
 315
 316         r = parse_uid(token, &u);
 317         if (r < 0)
 318                 return 0;
 319
 320         /* We ignore the passed value if anonymous authentication is
 321          * on anyway. */
 322         if (!b->anonymous_auth && u != b->ucred.uid)
 323                 return 0;
 324
 325         return 1;
 326 }
 327
 328 static int bus_socket_auth_write(sd_bus *b, const char *t) {
 329         char *p;
 330         size_t l;
 331
 332         assert(b);
 333         assert(t);
 334
 335         /* We only make use of the first iovec */
 336         assert(b->auth_index == 0 || b->auth_index == 1);
 337
 338         l = strlen(t);
 339         p = malloc(b->auth_iovec[0].iov_len + l);
 340         if (!p)
 341                 return -ENOMEM;
 342
 343         memcpy(p, b->auth_iovec[0].iov_base, b->auth_iovec[0].iov_len);
 344         memcpy(p + b->auth_iovec[0].iov_len, t, l);
 345
 346         b->auth_iovec[0].iov_base = p;
 347         b->auth_iovec[0].iov_len += l;
 348
 349         free(b->auth_buffer);
 350         b->auth_buffer = p;
 351         b->auth_index = 0;
 352         return 0;
 353 }
 354
 355 static int bus_socket_auth_write_ok(sd_bus *b) {
 356         char t[3 + 32 + 2 + 1];
 357
 358         assert(b);
 359
 360         snprintf(t, sizeof(t), "OK " SD_ID128_FORMAT_STR "\r\n", SD_ID128_FORMAT_VAL(b->server_id));
 361         char_array_0(t);
 362
 363         return bus_socket_auth_write(b, t);
 364 }
 365
 366 static int bus_socket_auth_verify_server(sd_bus *b) {
 367         char *e;
 368         const char *line;
 369         size_t l;
 370         bool processed = false;
 371         int r;
 372
 373         assert(b);
 374
 375         if (b->rbuffer_size < 1)
 376                 return 0;
 377
 378         /* First char must be a NUL byte */
 379         if (*(char*) b->rbuffer != 0)
 380                 return -EIO;
 381
 382         if (b->rbuffer_size < 3)
 383                 return 0;
 384
 385         /* Begin with the first line */
 386         if (b->auth_rbegin <= 0)
 387                 b->auth_rbegin = 1;
 388
 389         for (;;) {
 390                 /* Check if line is complete */
 391                 line = (char*) b->rbuffer + b->auth_rbegin;
 392                 e = memmem(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2);
 393                 if (!e)
 394                         return processed;
 395
 396                 l = e - line;
 397
 398                 if (line_begins(line, l, "AUTH ANONYMOUS")) {
 399
 400                         r = verify_anonymous_token(b, line + 14, l - 14);
 401                         if (r < 0)
 402                                 return r;
 403                         if (r == 0)
 404                                 r = bus_socket_auth_write(b, "REJECTED\r\n");
 405                         else {
 406                                 b->auth = BUS_AUTH_ANONYMOUS;
 407                                 r = bus_socket_auth_write_ok(b);
 408                         }
 409
 410                 } else if (line_begins(line, l, "AUTH EXTERNAL")) {
 411
 412                         r = verify_external_token(b, line + 13, l - 13);
 413                         if (r < 0)
 414                                 return r;
 415                         if (r == 0)
 416                                 r = bus_socket_auth_write(b, "REJECTED\r\n");
 417                         else {
 418                                 b->auth = BUS_AUTH_EXTERNAL;
 419                                 r = bus_socket_auth_write_ok(b);
 420                         }
 421
 422                 } else if (line_begins(line, l, "AUTH"))
 423                         r = bus_socket_auth_write(b, "REJECTED EXTERNAL ANONYMOUS\r\n");
 424                 else if (line_equals(line, l, "CANCEL") ||
 425                          line_begins(line, l, "ERROR")) {
 426
 427                         b->auth = _BUS_AUTH_INVALID;
 428                         r = bus_socket_auth_write(b, "REJECTED\r\n");
 429
 430                 } else if (line_equals(line, l, "BEGIN")) {
 431
 432                         if (b->auth == _BUS_AUTH_INVALID)
 433                                 r = bus_socket_auth_write(b, "ERROR\r\n");
 434                         else {
 435                                 /* We can't leave from the auth phase
 436                                  * before we haven't written
 437                                  * everything queued, so let's check
 438                                  * that */
 439
 440                                 if (bus_socket_auth_needs_write(b))
 441                                         return 1;
 442
 443                                 b->rbuffer_size -= (e + 2 - (char*) b->rbuffer);
 444                                 memmove(b->rbuffer, e + 2, b->rbuffer_size);
 445                                 return bus_start_running(b);
 446                         }
 447
 448                 } else if (line_begins(line, l, "DATA")) {
 449
 450                         if (b->auth == _BUS_AUTH_INVALID)
 451                                 r = bus_socket_auth_write(b, "ERROR\r\n");
 452                         else {
 453                                 if (b->auth == BUS_AUTH_ANONYMOUS)
 454                                         r = verify_anonymous_token(b, line + 4, l - 4);
 455                                 else
 456                                         r = verify_external_token(b, line + 4, l - 4);
 457
 458                                 if (r < 0)
 459                                         return r;
 460                                 if (r == 0) {
 461                                         b->auth = _BUS_AUTH_INVALID;
 462                                         r = bus_socket_auth_write(b, "REJECTED\r\n");
 463                                 } else
 464                                         r = bus_socket_auth_write_ok(b);
 465                         }
 466                 } else if (line_equals(line, l, "NEGOTIATE_UNIX_FD")) {
 467                         if (b->auth == _BUS_AUTH_INVALID || !(b->hello_flags & KDBUS_HELLO_ACCEPT_FD))
 468                                 r = bus_socket_auth_write(b, "ERROR\r\n");
 469                         else {
 470                                 b->can_fds = true;
 471                                 r = bus_socket_auth_write(b, "AGREE_UNIX_FD\r\n");
 472                         }
 473                 } else
 474                         r = bus_socket_auth_write(b, "ERROR\r\n");
 475
 476                 if (r < 0)
 477                         return r;
 478
 479                 b->auth_rbegin = e + 2 - (char*) b->rbuffer;
 480
 481                 processed = true;
 482         }
 483 }
 484
 485 static int bus_socket_auth_verify(sd_bus *b) {
 486         assert(b);
 487
 488         if (b->is_server)
 489                 return bus_socket_auth_verify_server(b);
 490         else
 491                 return bus_socket_auth_verify_client(b);
 492 }
 493
 494 static int bus_socket_read_auth(sd_bus *b) {
 495         struct msghdr mh;
 496         struct iovec iov;
 497         size_t n;
 498         ssize_t k;
 499         int r;
 500         void *p;
 501         union {
 502                 struct cmsghdr cmsghdr;
 503                 uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
 504                             CMSG_SPACE(sizeof(struct ucred)) +
 505                             CMSG_SPACE(NAME_MAX)]; /*selinux label */
 506         } control;
 507         struct cmsghdr *cmsg;
 508         bool handle_cmsg = false;
 509
 510         assert(b);
 511         assert(b->state == BUS_AUTHENTICATING);
 512
 513         r = bus_socket_auth_verify(b);
 514         if (r != 0)
 515                 return r;
 516
 517         n = MAX(256u, b->rbuffer_size * 2);
 518
 519         if (n > BUS_AUTH_SIZE_MAX)
 520                 n = BUS_AUTH_SIZE_MAX;
 521
 522         if (b->rbuffer_size >= n)
 523                 return -ENOBUFS;
 524
 525         p = realloc(b->rbuffer, n);
 526         if (!p)
 527                 return -ENOMEM;
 528
 529         b->rbuffer = p;
 530
 531         zero(iov);
 532         iov.iov_base = (uint8_t*) b->rbuffer + b->rbuffer_size;
 533         iov.iov_len = n - b->rbuffer_size;
 534
 535         if (b->prefer_readv)
 536                 k = readv(b->input_fd, &iov, 1);
 537         else {
 538                 zero(mh);
 539                 mh.msg_iov = &iov;
 540                 mh.msg_iovlen = 1;
 541                 mh.msg_control = &control;
 542                 mh.msg_controllen = sizeof(control);
 543
 544                 k = recvmsg(b->input_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
 545                 if (k < 0 && errno == ENOTSOCK) {
 546                         b->prefer_readv = true;
 547                         k = readv(b->input_fd, &iov, 1);
 548                 } else
 549                         handle_cmsg = true;
 550         }
 551         if (k < 0)
 552                 return errno == EAGAIN ? 0 : -errno;
 553         if (k == 0)
 554                 return -ECONNRESET;
 555
 556         b->rbuffer_size += k;
 557
 558         if (handle_cmsg) {
 559                 for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
 560                         if (cmsg->cmsg_level == SOL_SOCKET &&
 561                             cmsg->cmsg_type == SCM_RIGHTS) {
 562                                 int j;
 563
 564                                 /* Whut? We received fds during the auth
 565                                  * protocol? Somebody is playing games with
 566                                  * us. Close them all, and fail */
 567                                 j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
 568                                 close_many((int*) CMSG_DATA(cmsg), j);
 569                                 return -EIO;
 570
 571                         } else if (cmsg->cmsg_level == SOL_SOCKET &&
 572                                    cmsg->cmsg_type == SCM_CREDENTIALS &&
 573                                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
 574
 575                                 /* Ignore bogus data, which we might
 576                                  * get on socketpair() sockets */
 577                                 if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) {
 578                                         memcpy(&b->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
 579                                         b->ucred_valid = true;
 580                                 }
 581
 582                         } else if (cmsg->cmsg_level == SOL_SOCKET &&
 583                                    cmsg->cmsg_type == SCM_SECURITY) {
 584
 585                                 size_t l;
 586
 587                                 l = cmsg->cmsg_len - CMSG_LEN(0);
 588                                 if (l > 0) {
 589                                         memcpy(&b->label, CMSG_DATA(cmsg), l);
 590                                         b->label[l] = 0;
 591                                 }
 592                         }
 593                 }
 594         }
 595
 596         r = bus_socket_auth_verify(b);
 597         if (r != 0)
 598                 return r;
 599
 600         return 1;
 601 }
 602
 603 int bus_socket_setup(sd_bus *b) {
 604         int enable;
 605         socklen_t l;
 606
 607         assert(b);
 608
 609         /* Enable SO_PASSCRED + SO_PASSEC. We try this on any
 610          * socket, just in case. */
 611         enable = !b->bus_client;
 612         setsockopt(b->input_fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable));
 613
 614         enable = !b->bus_client && (b->hello_flags & KDBUS_HELLO_ATTACH_SECLABEL);
 615         setsockopt(b->input_fd, SOL_SOCKET, SO_PASSSEC, &enable, sizeof(enable));
 616
 617         /* Increase the buffers to a MB */
 618         fd_inc_rcvbuf(b->input_fd, 1024*1024);
 619         fd_inc_sndbuf(b->output_fd, 1024*1024);
 620
 621         /* Get the peer for socketpair() sockets */
 622         l = sizeof(b->ucred);
 623         if (getsockopt(b->input_fd, SOL_SOCKET, SO_PEERCRED, &b->ucred, &l) >= 0 && l >= sizeof(b->ucred))
 624                 b->ucred_valid = b->ucred.pid > 0;
 625
 626         return 0;
 627 }
 628
 629 static int bus_socket_start_auth_client(sd_bus *b) {
 630         size_t l;
 631         const char *auth_suffix, *auth_prefix;
 632
 633         assert(b);
 634
 635         if (b->anonymous_auth) {
 636                 auth_prefix = "\0AUTH ANONYMOUS ";
 637
 638                 /* For ANONYMOUS auth we send some arbitrary "trace" string */
 639                 l = 9;
 640                 b->auth_buffer = hexmem("anonymous", l);
 641         } else {
 642                 char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
 643
 644                 auth_prefix = "\0AUTH EXTERNAL ";
 645
 646                 snprintf(text, sizeof(text), "%lu", (unsigned long) geteuid());
 647                 char_array_0(text);
 648
 649                 l = strlen(text);
 650                 b->auth_buffer = hexmem(text, l);
 651         }
 652
 653         if (!b->auth_buffer)
 654                 return -ENOMEM;
 655
 656         if (b->hello_flags & KDBUS_HELLO_ACCEPT_FD)
 657                 auth_suffix = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
 658         else
 659                 auth_suffix = "\r\nBEGIN\r\n";
 660
 661         b->auth_iovec[0].iov_base = (void*) auth_prefix;
 662         b->auth_iovec[0].iov_len = 1 + strlen(auth_prefix + 1);
 663         b->auth_iovec[1].iov_base = (void*) b->auth_buffer;
 664         b->auth_iovec[1].iov_len = l * 2;
 665         b->auth_iovec[2].iov_base = (void*) auth_suffix;
 666         b->auth_iovec[2].iov_len = strlen(auth_suffix);
 667
 668         return bus_socket_write_auth(b);
 669 }
 670
 671 int bus_socket_start_auth(sd_bus *b) {
 672         assert(b);
 673
 674         b->state = BUS_AUTHENTICATING;
 675         b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_DEFAULT_TIMEOUT;
 676
 677         if (sd_is_socket(b->input_fd, AF_UNIX, 0, 0) <= 0)
 678                 b->hello_flags &= ~KDBUS_HELLO_ACCEPT_FD;
 679
 680         if (b->output_fd != b->input_fd)
 681                 if (sd_is_socket(b->output_fd, AF_UNIX, 0, 0) <= 0)
 682                         b->hello_flags &= ~KDBUS_HELLO_ACCEPT_FD;
 683
 684         if (b->is_server)
 685                 return bus_socket_read_auth(b);
 686         else
 687                 return bus_socket_start_auth_client(b);
 688 }
 689
 690 int bus_socket_connect(sd_bus *b) {
 691         int r;
 692
 693         assert(b);
 694         assert(b->input_fd < 0);
 695         assert(b->output_fd < 0);
 696         assert(b->sockaddr.sa.sa_family != AF_UNSPEC);
 697
 698         b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 699         if (b->input_fd < 0)
 700                 return -errno;
 701
 702         b->output_fd = b->input_fd;
 703
 704         r = bus_socket_setup(b);
 705         if (r < 0)
 706                 return r;
 707
 708         r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
 709         if (r < 0) {
 710                 if (errno == EINPROGRESS)
 711                         return 1;
 712
 713                 return -errno;
 714         }
 715
 716         return bus_socket_start_auth(b);
 717 }
 718
 719 int bus_socket_exec(sd_bus *b) {
 720         int s[2], r;
 721         pid_t pid;
 722
 723         assert(b);
 724         assert(b->input_fd < 0);
 725         assert(b->output_fd < 0);
 726         assert(b->exec_path);
 727
 728         r = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s);
 729         if (r < 0)
 730                 return -errno;
 731
 732         pid = fork();
 733         if (pid < 0) {
 734                 close_pipe(s);
 735                 return -errno;
 736         }
 737         if (pid == 0) {
 738                 /* Child */
 739
 740                 reset_all_signal_handlers();
 741
 742                 close_all_fds(s+1, 1);
 743
 744                 assert_se(dup3(s[1], STDIN_FILENO, 0) == STDIN_FILENO);
 745                 assert_se(dup3(s[1], STDOUT_FILENO, 0) == STDOUT_FILENO);
 746
 747                 if (s[1] != STDIN_FILENO && s[1] != STDOUT_FILENO)
 748                         close_nointr_nofail(s[1]);
 749
 750                 fd_cloexec(STDIN_FILENO, false);
 751                 fd_cloexec(STDOUT_FILENO, false);
 752                 fd_nonblock(STDIN_FILENO, false);
 753                 fd_nonblock(STDOUT_FILENO, false);
 754
 755                 if (b->exec_argv)
 756                         execvp(b->exec_path, b->exec_argv);
 757                 else {
 758                         const char *argv[] = { b->exec_path, NULL };
 759                         execvp(b->exec_path, (char**) argv);
 760                 }
 761
 762                 _exit(EXIT_FAILURE);
 763         }
 764
 765         close_nointr_nofail(s[1]);
 766         b->output_fd = b->input_fd = s[0];
 767
 768         return bus_socket_start_auth(b);
 769 }
 770
 771 int bus_socket_take_fd(sd_bus *b) {
 772         int  r;
 773         assert(b);
 774
 775         r = bus_socket_setup(b);
 776         if (r < 0)
 777                 return r;
 778
 779         return bus_socket_start_auth(b);
 780 }
 781
 782 int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) {
 783         struct iovec *iov;
 784         ssize_t k;
 785         size_t n;
 786         unsigned j;
 787         int r;
 788
 789         assert(bus);
 790         assert(m);
 791         assert(idx);
 792         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 793
 794         if (*idx >= BUS_MESSAGE_SIZE(m))
 795                 return 0;
 796
 797         r = bus_message_setup_iovec(m);
 798         if (r < 0)
 799                 return r;
 800
 801         n = m->n_iovec * sizeof(struct iovec);
 802         iov = alloca(n);
 803         memcpy(iov, m->iovec, n);
 804
 805         j = 0;
 806         iovec_advance(iov, &j, *idx);
 807
 808         if (bus->prefer_writev)
 809                 k = writev(bus->output_fd, iov, m->n_iovec);
 810         else {
 811                 struct msghdr mh;
 812                 zero(mh);
 813
 814                 if (m->n_fds > 0) {
 815                         struct cmsghdr *control;
 816                         control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds));
 817
 818                         mh.msg_control = control;
 819                         control->cmsg_level = SOL_SOCKET;
 820                         control->cmsg_type = SCM_RIGHTS;
 821                         mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds);
 822                         memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds);
 823                 }
 824
 825                 mh.msg_iov = iov;
 826                 mh.msg_iovlen = m->n_iovec;
 827
 828                 k = sendmsg(bus->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
 829                 if (k < 0 && errno == ENOTSOCK) {
 830                         bus->prefer_writev = true;
 831                         k = writev(bus->output_fd, iov, m->n_iovec);
 832                 }
 833         }
 834
 835         if (k < 0)
 836                 return errno == EAGAIN ? 0 : -errno;
 837
 838         *idx += (size_t) k;
 839         return 1;
 840 }
 841
 842 static int bus_socket_read_message_need(sd_bus *bus, size_t *need) {
 843         uint32_t a, b;
 844         uint8_t e;
 845         uint64_t sum;
 846
 847         assert(bus);
 848         assert(need);
 849         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 850
 851         if (bus->rbuffer_size < sizeof(struct bus_header)) {
 852                 *need = sizeof(struct bus_header) + 8;
 853
 854                 /* Minimum message size:
 855                  *
 856                  * Header +
 857                  *
 858                  *  Method Call: +2 string headers
 859                  *       Signal: +3 string headers
 860                  * Method Error: +1 string headers
 861                  *               +1 uint32 headers
 862                  * Method Reply: +1 uint32 headers
 863                  *
 864                  * A string header is at least 9 bytes
 865                  * A uint32 header is at least 8 bytes
 866                  *
 867                  * Hence the minimum message size of a valid message
 868                  * is header + 8 bytes */
 869
 870                 return 0;
 871         }
 872
 873         a = ((const uint32_t*) bus->rbuffer)[1];
 874         b = ((const uint32_t*) bus->rbuffer)[3];
 875
 876         e = ((const uint8_t*) bus->rbuffer)[0];
 877         if (e == SD_BUS_LITTLE_ENDIAN) {
 878                 a = le32toh(a);
 879                 b = le32toh(b);
 880         } else if (e == SD_BUS_BIG_ENDIAN) {
 881                 a = be32toh(a);
 882                 b = be32toh(b);
 883         } else
 884                 return -EBADMSG;
 885
 886         sum = (uint64_t) sizeof(struct bus_header) + (uint64_t) ALIGN_TO(b, 8) + (uint64_t) a;
 887         if (sum >= BUS_MESSAGE_SIZE_MAX)
 888                 return -ENOBUFS;
 889
 890         *need = (size_t) sum;
 891         return 0;
 892 }
 893
 894 static int bus_socket_make_message(sd_bus *bus, size_t size, sd_bus_message **m) {
 895         sd_bus_message *t;
 896         void *b;
 897         int r;
 898
 899         assert(bus);
 900         assert(m);
 901         assert(bus->rbuffer_size >= size);
 902         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 903
 904         if (bus->rbuffer_size > size) {
 905                 b = memdup((const uint8_t*) bus->rbuffer + size,
 906                            bus->rbuffer_size - size);
 907                 if (!b)
 908                         return -ENOMEM;
 909         } else
 910                 b = NULL;
 911
 912         r = bus_message_from_malloc(bus->rbuffer, size,
 913                                     bus->fds, bus->n_fds,
 914                                     bus->ucred_valid ? &bus->ucred : NULL,
 915                                     bus->label[0] ? bus->label : NULL,
 916                                     &t);
 917         if (r < 0) {
 918                 free(b);
 919                 return r;
 920         }
 921
 922         bus->rbuffer = b;
 923         bus->rbuffer_size -= size;
 924
 925         bus->fds = NULL;
 926         bus->n_fds = 0;
 927
 928         *m = t;
 929         return 1;
 930 }
 931
 932 int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
 933         struct msghdr mh;
 934         struct iovec iov;
 935         ssize_t k;
 936         size_t need;
 937         int r;
 938         void *b;
 939         union {
 940                 struct cmsghdr cmsghdr;
 941                 uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
 942                             CMSG_SPACE(sizeof(struct ucred)) +
 943                             CMSG_SPACE(NAME_MAX)]; /*selinux label */
 944         } control;
 945         struct cmsghdr *cmsg;
 946         bool handle_cmsg = false;
 947
 948         assert(bus);
 949         assert(m);
 950         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 951
 952         r = bus_socket_read_message_need(bus, &need);
 953         if (r < 0)
 954                 return r;
 955
 956         if (bus->rbuffer_size >= need)
 957                 return bus_socket_make_message(bus, need, m);
 958
 959         b = realloc(bus->rbuffer, need);
 960         if (!b)
 961                 return -ENOMEM;
 962
 963         bus->rbuffer = b;
 964
 965         zero(iov);
 966         iov.iov_base = (uint8_t*) bus->rbuffer + bus->rbuffer_size;
 967         iov.iov_len = need - bus->rbuffer_size;
 968
 969         if (bus->prefer_readv)
 970                 k = readv(bus->input_fd, &iov, 1);
 971         else {
 972                 zero(mh);
 973                 mh.msg_iov = &iov;
 974                 mh.msg_iovlen = 1;
 975                 mh.msg_control = &control;
 976                 mh.msg_controllen = sizeof(control);
 977
 978                 k = recvmsg(bus->input_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
 979                 if (k < 0 && errno == ENOTSOCK) {
 980                         bus->prefer_readv = true;
 981                         k = readv(bus->input_fd, &iov, 1);
 982                 } else
 983                         handle_cmsg = true;
 984         }
 985         if (k < 0)
 986                 return errno == EAGAIN ? 0 : -errno;
 987         if (k == 0)
 988                 return -ECONNRESET;
 989
 990         bus->rbuffer_size += k;
 991
 992         if (handle_cmsg) {
 993                 for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
 994                         if (cmsg->cmsg_level == SOL_SOCKET &&
 995                             cmsg->cmsg_type == SCM_RIGHTS) {
 996                                 int n, *f;
 997
 998                                 n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
 999
1000                                 if (!bus->can_fds) {
1001                                         /* Whut? We received fds but this
1002                                          * isn't actually enabled? Close them,
1003                                          * and fail */
1004
1005                                         close_many((int*) CMSG_DATA(cmsg), n);
1006                                         return -EIO;
1007                                 }
1008
1009                                 f = realloc(bus->fds, sizeof(int) + (bus->n_fds + n));
1010                                 if (!f) {
1011                                         close_many((int*) CMSG_DATA(cmsg), n);
1012                                         return -ENOMEM;
1013                                 }
1014
1015                                 memcpy(f + bus->n_fds, CMSG_DATA(cmsg), n * sizeof(int));
1016                                 bus->fds = f;
1017                                 bus->n_fds += n;
1018                         } else if (cmsg->cmsg_level == SOL_SOCKET &&
1019                                    cmsg->cmsg_type == SCM_CREDENTIALS &&
1020                                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
1021
1022                                 /* Ignore bogus data, which we might
1023                                  * get on socketpair() sockets */
1024                                 if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) {
1025                                         memcpy(&bus->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
1026                                         bus->ucred_valid = true;
1027                                 }
1028
1029                         } else if (cmsg->cmsg_level == SOL_SOCKET &&
1030                                    cmsg->cmsg_type == SCM_SECURITY) {
1031
1032                                 size_t l;
1033                                 l = cmsg->cmsg_len - CMSG_LEN(0);
1034                                 if (l > 0) {
1035                                         memcpy(&bus->label, CMSG_DATA(cmsg), l);
1036                                         bus->label[l] = 0;
1037                                 }
1038                         }
1039                 }
1040         }
1041
1042         r = bus_socket_read_message_need(bus, &need);
1043         if (r < 0)
1044                 return r;
1045
1046         if (bus->rbuffer_size >= need)
1047                 return bus_socket_make_message(bus, need, m);
1048
1049         return 1;
1050 }
1051
1052 int bus_socket_process_opening(sd_bus *b) {
1053         int error = 0;
1054         socklen_t slen = sizeof(error);
1055         struct pollfd p = {
1056                 .fd = b->output_fd,
1057                 .events = POLLOUT,
1058         };
1059         int r;
1060
1061         assert(b->state == BUS_OPENING);
1062
1063         r = poll(&p, 1, 0);
1064         if (r < 0)
1065                 return -errno;
1066
1067         if (!(p.revents & (POLLOUT|POLLERR|POLLHUP)))
1068                 return 0;
1069
1070         r = getsockopt(b->output_fd, SOL_SOCKET, SO_ERROR, &error, &slen);
1071         if (r < 0)
1072                 b->last_connect_error = errno;
1073         else if (error != 0)
1074                 b->last_connect_error = error;
1075         else if (p.revents & (POLLERR|POLLHUP))
1076                 b->last_connect_error = ECONNREFUSED;
1077         else
1078                 return bus_socket_start_auth(b);
1079
1080         return bus_next_address(b);
1081 }
1082
1083 int bus_socket_process_authenticating(sd_bus *b) {
1084         int r;
1085
1086         assert(b);
1087         assert(b->state == BUS_AUTHENTICATING);
1088
1089         if (now(CLOCK_MONOTONIC) >= b->auth_timeout)
1090                 return -ETIMEDOUT;
1091
1092         r = bus_socket_write_auth(b);
1093         if (r != 0)
1094                 return r;
1095
1096         return bus_socket_read_auth(b);
1097 }