kcm/connect.c

   1 /*
   2  * Copyright (c) 1997-2005 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "kcm_locl.h"
  35
  36 RCSID("$Id$");
  37
  38 struct descr {
  39     int s;
  40     int type;
  41     char *path;
  42     unsigned char *buf;
  43     size_t size;
  44     size_t len;
  45     time_t timeout;
  46     struct sockaddr_storage __ss;
  47     struct sockaddr *sa;
  48     socklen_t sock_len;
  49     kcm_client peercred;
  50 };
  51
  52 static void
  53 init_descr(struct descr *d)
  54 {
  55     memset(d, 0, sizeof(*d));
  56     d->sa = (struct sockaddr *)&d->__ss;
  57     d->s = -1;
  58 }
  59
  60 /*
  61  * re-initialize all `n' ->sa in `d'.
  62  */
  63
  64 static void
  65 reinit_descrs (struct descr *d, int n)
  66 {
  67     int i;
  68
  69     for (i = 0; i < n; ++i)
  70         d[i].sa = (struct sockaddr *)&d[i].__ss;
  71 }
  72
  73 /*
  74  * Update peer credentials from socket.
  75  *
  76  * SCM_CREDS can only be updated the first time there is read data to
  77  * read from the filedescriptor, so if we read do it before this
  78  * point, the cred data might not be is not there yet.
  79  */
  80
  81 static int
  82 update_client_creds(int s, kcm_client *peer)
  83 {
  84 #ifdef GETPEERUCRED
  85     /* Solaris 10 */
  86     {
  87         ucred_t *peercred;
  88
  89         if (getpeerucred(s, &peercred) != 0) {
  90             peer->uid = ucred_geteuid(peercred);
  91             peer->gid = ucred_getegid(peercred);
  92             peer->pid = 0;
  93             ucred_free(peercred);
  94             return 0;
  95         }
  96     }
  97 #endif
  98 #ifdef GETPEEREID
  99     /* FreeBSD, OpenBSD */
 100     {
 101         uid_t uid;
 102         gid_t gid;
 103
 104         if (getpeereid(s, &uid, &gid) == 0) {
 105             peer->uid = uid;
 106             peer->gid = gid;
 107             peer->pid = 0;
 108             return 0;
 109         }
 110     }
 111 #endif
 112 #ifdef SO_PEERCRED
 113     /* Linux */
 114     {
 115         struct ucred pc;
 116         socklen_t pclen = sizeof(pc);
 117
 118         if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, (void *)&pc, &pclen) == 0) {
 119             peer->uid = pc.uid;
 120             peer->gid = pc.gid;
 121             peer->pid = pc.pid;
 122             return 0;
 123         }
 124     }
 125 #endif
 126 #if defined(LOCAL_PEERCRED) && defined(XUCRED_VERSION)
 127     {
 128         struct xucred peercred;
 129         socklen_t peercredlen = sizeof(peercred);
 130
 131         if (getsockopt(s, LOCAL_PEERCRED, 1,
 132                        (void *)&peercred, &peercredlen) == 0
 133             && peercred.cr_version == XUCRED_VERSION)
 134         {
 135             peer->uid = peercred.cr_uid;
 136             peer->gid = peercred.cr_gid;
 137             peer->pid = 0;
 138             return 0;
 139         }
 140     }
 141 #endif
 142 #if defined(SOCKCREDSIZE) && defined(SCM_CREDS)
 143     /* NetBSD */
 144     if (peer->uid == -1) {
 145         struct msghdr msg;
 146         socklen_t crmsgsize;
 147         void *crmsg;
 148         struct cmsghdr *cmp;
 149         struct sockcred *sc;
 150
 151         memset(&msg, 0, sizeof(msg));
 152         crmsgsize = CMSG_SPACE(SOCKCREDSIZE(NGROUPS));
 153         if (crmsgsize == 0)
 154             return 1 ;
 155
 156         crmsg = malloc(crmsgsize);
 157         if (crmsg == NULL)
 158             goto failed_scm_creds;
 159
 160         memset(crmsg, 0, crmsgsize);
 161
 162         msg.msg_control = crmsg;
 163         msg.msg_controllen = crmsgsize;
 164
 165         if (recvmsg(s, &msg, 0) < 0) {
 166             free(crmsg);
 167             goto failed_scm_creds;
 168         }
 169
 170         if (msg.msg_controllen == 0 || (msg.msg_flags & MSG_CTRUNC) != 0) {
 171             free(crmsg);
 172             goto failed_scm_creds;
 173         }
 174
 175         cmp = CMSG_FIRSTHDR(&msg);
 176         if (cmp->cmsg_level != SOL_SOCKET || cmp->cmsg_type != SCM_CREDS) {
 177             free(crmsg);
 178             goto failed_scm_creds;
 179         }
 180
 181         sc = (struct sockcred *)(void *)CMSG_DATA(cmp);
 182
 183         peer->uid = sc->sc_euid;
 184         peer->gid = sc->sc_egid;
 185         peer->pid = 0;
 186
 187         free(crmsg);
 188         return 0;
 189     } else {
 190         /* we already got the cred, just return it */
 191         return 0;
 192     }
 193  failed_scm_creds:
 194 #endif
 195     krb5_warn(kcm_context, errno, "failed to determine peer identity");
 196     return 1;
 197 }
 198
 199
 200 /*
 201  * Create the socket (family, type, port) in `d'
 202  */
 203
 204 static void
 205 init_socket(struct descr *d)
 206 {
 207     struct sockaddr_un un;
 208     struct sockaddr *sa = (struct sockaddr *)&un;
 209     krb5_socklen_t sa_size = sizeof(un);
 210
 211     init_descr (d);
 212
 213     un.sun_family = AF_UNIX;
 214
 215     if (socket_path != NULL)
 216         d->path = socket_path;
 217     else
 218         d->path = _PATH_KCM_SOCKET;
 219
 220     strlcpy(un.sun_path, d->path, sizeof(un.sun_path));
 221
 222     d->s = socket(AF_UNIX, SOCK_STREAM, 0);
 223     if (d->s < 0){
 224         krb5_warn(kcm_context, errno, "socket(%d, %d, 0)", AF_UNIX, SOCK_STREAM);
 225         d->s = -1;
 226         return;
 227     }
 228 #if defined(HAVE_SETSOCKOPT) && defined(SOL_SOCKET) && defined(SO_REUSEADDR)
 229     {
 230         int one = 1;
 231         setsockopt(d->s, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof(one));
 232     }
 233 #endif
 234 #ifdef LOCAL_CREDS
 235     {
 236         int one = 1;
 237         setsockopt(d->s, 0, LOCAL_CREDS, (void *)&one, sizeof(one));
 238     }
 239 #endif
 240
 241     d->type = SOCK_STREAM;
 242
 243     unlink(d->path);
 244
 245     if (bind(d->s, sa, sa_size) < 0) {
 246         krb5_warn(kcm_context, errno, "bind %s", un.sun_path);
 247         close(d->s);
 248         d->s = -1;
 249         return;
 250     }
 251
 252     if (listen(d->s, SOMAXCONN) < 0) {
 253         krb5_warn(kcm_context, errno, "listen %s", un.sun_path);
 254         close(d->s);
 255         d->s = -1;
 256         return;
 257     }
 258
 259     chmod(d->path, 0777);
 260
 261     return;
 262 }
 263
 264 /*
 265  * Allocate descriptors for all the sockets that we should listen on
 266  * and return the number of them.
 267  */
 268
 269 static int
 270 init_sockets(struct descr **desc)
 271 {
 272     struct descr *d;
 273     size_t num = 0;
 274
 275     d = (struct descr *)malloc(sizeof(*d));
 276     if (d == NULL) {
 277         krb5_errx(kcm_context, 1, "malloc failed");
 278     }
 279
 280     init_socket(d);
 281     if (d->s != -1) {
 282         kcm_log(5, "listening on domain socket %s", d->path);
 283         num++;
 284     }
 285
 286     reinit_descrs (d, num);
 287     *desc = d;
 288
 289     return num;
 290 }
 291
 292 /*
 293  * handle the request in `buf, len', from `addr' (or `from' as a string),
 294  * sending a reply in `reply'.
 295  */
 296
 297 static int
 298 process_request(unsigned char *buf,
 299                 size_t len,
 300                 krb5_data *reply,
 301                 kcm_client *client)
 302 {
 303     krb5_data request;
 304
 305     if (len < 4) {
 306         kcm_log(1, "malformed request from process %d (too short)",
 307                 client->pid);
 308         return -1;
 309     }
 310
 311     if (buf[0] != KCM_PROTOCOL_VERSION_MAJOR ||
 312         buf[1] != KCM_PROTOCOL_VERSION_MINOR) {
 313         kcm_log(1, "incorrect protocol version %d.%d from process %d",
 314                 buf[0], buf[1], client->pid);
 315         return -1;
 316     }
 317
 318     buf += 2;
 319     len -= 2;
 320
 321     /* buf is now pointing at opcode */
 322
 323     request.data = buf;
 324     request.length = len;
 325
 326     return kcm_dispatch(kcm_context, client, &request, reply);
 327 }
 328
 329 /*
 330  * Handle the request in `buf, len' to socket `d'
 331  */
 332
 333 static void
 334 do_request(void *buf, size_t len, struct descr *d)
 335 {
 336     krb5_error_code ret;
 337     krb5_data reply;
 338
 339     reply.length = 0;
 340
 341     ret = process_request(buf, len, &reply, &d->peercred);
 342     if (reply.length != 0) {
 343         unsigned char len[4];
 344         struct msghdr msghdr;
 345         struct iovec iov[2];
 346
 347         kcm_log(5, "sending %lu bytes to process %d",
 348                 (unsigned long)reply.length,
 349                 (int)d->peercred.pid);
 350
 351         memset (&msghdr, 0, sizeof(msghdr));
 352         msghdr.msg_name       = NULL;
 353         msghdr.msg_namelen    = 0;
 354         msghdr.msg_iov        = iov;
 355         msghdr.msg_iovlen     = sizeof(iov)/sizeof(*iov);
 356 #if 0
 357         msghdr.msg_control    = NULL;
 358         msghdr.msg_controllen = 0;
 359 #endif
 360
 361         len[0] = (reply.length >> 24) & 0xff;
 362         len[1] = (reply.length >> 16) & 0xff;
 363         len[2] = (reply.length >> 8) & 0xff;
 364         len[3] = reply.length & 0xff;
 365
 366         iov[0].iov_base       = (void*)len;
 367         iov[0].iov_len        = 4;
 368         iov[1].iov_base       = reply.data;
 369         iov[1].iov_len        = reply.length;
 370
 371         if (sendmsg (d->s, &msghdr, 0) < 0) {
 372             kcm_log (0, "sendmsg(%d): %d %s", (int)d->peercred.pid,
 373                      errno, strerror(errno));
 374             krb5_data_free(&reply);
 375             return;
 376         }
 377
 378         krb5_data_free(&reply);
 379     }
 380
 381     if (ret) {
 382         kcm_log(0, "Failed processing %lu byte request from process %d",
 383                 (unsigned long)len, d->peercred.pid);
 384     }
 385 }
 386
 387 static void
 388 clear_descr(struct descr *d)
 389 {
 390     if(d->buf)
 391         memset(d->buf, 0, d->size);
 392     d->len = 0;
 393     if(d->s != -1)
 394         close(d->s);
 395     d->s = -1;
 396 }
 397
 398 #define STREAM_TIMEOUT 4
 399
 400 /*
 401  * accept a new stream connection on `d[parent]' and store it in `d[child]'
 402  */
 403
 404 static void
 405 add_new_stream (struct descr *d, int parent, int child)
 406 {
 407     int s;
 408
 409     if (child == -1)
 410         return;
 411
 412     d[child].peercred.pid = -1;
 413     d[child].peercred.uid = -1;
 414     d[child].peercred.gid = -1;
 415
 416     d[child].sock_len = sizeof(d[child].__ss);
 417     s = accept(d[parent].s, d[child].sa, &d[child].sock_len);
 418     if(s < 0) {
 419         krb5_warn(kcm_context, errno, "accept");
 420         return;
 421     }
 422
 423     if (s >= FD_SETSIZE) {
 424         krb5_warnx(kcm_context, "socket FD too large");
 425         close (s);
 426         return;
 427     }
 428
 429     d[child].s = s;
 430     d[child].timeout = time(NULL) + STREAM_TIMEOUT;
 431     d[child].type = SOCK_STREAM;
 432 }
 433
 434 /*
 435  * Grow `d' to handle at least `n'.
 436  * Return != 0 if fails
 437  */
 438
 439 static int
 440 grow_descr (struct descr *d, size_t n)
 441 {
 442     if (d->size - d->len < n) {
 443         unsigned char *tmp;
 444         size_t grow;
 445
 446         grow = max(1024, d->len + n);
 447         if (d->size + grow > max_request) {
 448             kcm_log(0, "Request exceeds max request size (%lu bytes).",
 449                     (unsigned long)d->size + grow);
 450             clear_descr(d);
 451             return -1;
 452         }
 453         tmp = realloc (d->buf, d->size + grow);
 454         if (tmp == NULL) {
 455             kcm_log(0, "Failed to re-allocate %lu bytes.",
 456                     (unsigned long)d->size + grow);
 457             clear_descr(d);
 458             return -1;
 459         }
 460         d->size += grow;
 461         d->buf = tmp;
 462     }
 463     return 0;
 464 }
 465
 466 /*
 467  * Handle incoming data to the stream socket in `d[index]'
 468  */
 469
 470 static void
 471 handle_stream(struct descr *d, int index, int min_free)
 472 {
 473     unsigned char buf[1024];
 474     int n;
 475     int ret = 0;
 476
 477     if (d[index].timeout == 0) {
 478         add_new_stream (d, index, min_free);
 479         return;
 480     }
 481
 482     if (update_client_creds(d[index].s, &d[index].peercred)) {
 483         krb5_warnx(kcm_context, "failed to update peer identity");
 484         clear_descr(d + index);
 485         return;
 486     }
 487
 488     if (d[index].peercred.uid == -1) {
 489         krb5_warnx(kcm_context, "failed to determine peer identity");
 490         clear_descr (d + index);
 491         return;
 492     }
 493
 494     n = recvfrom(d[index].s, buf, sizeof(buf), 0, NULL, NULL);
 495     if (n < 0) {
 496         krb5_warn(kcm_context, errno, "recvfrom");
 497         return;
 498     } else if (n == 0) {
 499         krb5_warnx(kcm_context, "connection closed before end of data "
 500                    "after %lu bytes from process %ld",
 501                    (unsigned long) d[index].len, (long) d[index].peercred.pid);
 502         clear_descr (d + index);
 503         return;
 504     }
 505     if (grow_descr (&d[index], n))
 506         return;
 507     memcpy(d[index].buf + d[index].len, buf, n);
 508     d[index].len += n;
 509     if (d[index].len > 4) {
 510         krb5_storage *sp;
 511         int32_t len;
 512
 513         sp = krb5_storage_from_mem(d[index].buf, d[index].len);
 514         if (sp == NULL) {
 515             kcm_log (0, "krb5_storage_from_mem failed");
 516             ret = -1;
 517         } else {
 518             krb5_ret_int32(sp, &len);
 519             krb5_storage_free(sp);
 520             if (d[index].len - 4 >= len) {
 521                 memmove(d[index].buf, d[index].buf + 4, d[index].len - 4);
 522                 ret = 1;
 523             } else
 524                 ret = 0;
 525         }
 526     }
 527     if (ret < 0)
 528         return;
 529     else if (ret == 1) {
 530         do_request(d[index].buf, d[index].len, &d[index]);
 531         clear_descr(d + index);
 532     }
 533 }
 534
 535 #ifdef HAVE_DOOR_CREATE
 536
 537 static void
 538 kcm_door_server(void  *cookie, char *argp, size_t arg_size,
 539                 door_desc_t *dp, uint_t n_desc)
 540 {
 541     kcm_client peercred;
 542     door_cred_t cred;
 543     krb5_error_code ret;
 544     krb5_data reply;
 545     size_t length;
 546     char *p;
 547
 548     reply.length = 0;
 549
 550     p = NULL;
 551     length = 0;
 552
 553     if (door_cred(&cred) != 0) {
 554         kcm_log(0, "door_cred failed with %s", strerror(errno));
 555         goto out;
 556     }
 557
 558     peercred.uid = cred.dc_euid;
 559     peercred.gid = cred.dc_egid;
 560     peercred.pid = cred.dc_pid;
 561
 562     ret = process_request((unsigned char*)argp, arg_size, &reply, &peercred);
 563     if (reply.length != 0) {
 564         p = alloca(reply.length); /* XXX don't use alloca */
 565         if (p) {
 566             memcpy(p, reply.data, reply.length);
 567             length = reply.length;
 568         }
 569         krb5_data_free(&reply);
 570     }
 571
 572  out:
 573     door_return(p, length, NULL, 0);
 574 }
 575
 576 static void
 577 kcm_setup_door(void)
 578 {
 579     int fd, ret;
 580     char *path;
 581
 582     fd = door_create(kcm_door_server, NULL, 0);
 583     if (fd < 0)
 584         krb5_err(kcm_context, 1, errno, "Failed to create door");
 585
 586     if (door_path != NULL)
 587         path = door_path;
 588     else
 589         path = _PATH_KCM_DOOR;
 590
 591     unlink(path);
 592     ret = open(path, O_RDWR | O_CREAT, 0666);
 593     if (ret < 0)
 594         krb5_err(kcm_context, 1, errno, "Failed to create/open door");
 595     close(ret);
 596
 597     ret = fattach(fd, path);
 598     if (ret < 0)
 599         krb5_err(kcm_context, 1, errno, "Failed to attach door");
 600
 601 }
 602 #endif /* HAVE_DOOR_CREATE */
 603
 604
 605 void
 606 kcm_loop(void)
 607 {
 608     struct descr *d;
 609     unsigned int ndescr;
 610
 611 #ifdef HAVE_DOOR_CREATE
 612     kcm_setup_door();
 613 #endif
 614
 615     ndescr = init_sockets(&d);
 616     if (ndescr <= 0) {
 617         krb5_warnx(kcm_context, "No sockets!");
 618 #ifndef HAVE_DOOR_CREATE
 619         exit(1);
 620 #endif
 621     }
 622     while (exit_flag == 0){
 623         struct timeval tmout;
 624         fd_set fds;
 625         int min_free = -1;
 626         int max_fd = 0;
 627         int i;
 628
 629         FD_ZERO(&fds);
 630         for(i = 0; i < ndescr; i++) {
 631             if (d[i].s >= 0){
 632                 if(d[i].type == SOCK_STREAM &&
 633                    d[i].timeout && d[i].timeout < time(NULL)) {
 634                     kcm_log(1, "Stream connection from %d expired after %lu bytes",
 635                             d[i].peercred.pid, (unsigned long)d[i].len);
 636                     clear_descr(&d[i]);
 637                     continue;
 638                 }
 639                 if (max_fd < d[i].s)
 640                     max_fd = d[i].s;
 641                 if (max_fd >= FD_SETSIZE)
 642                     krb5_errx(kcm_context, 1, "fd too large");
 643                 FD_SET(d[i].s, &fds);
 644             } else if (min_free < 0 || i < min_free)
 645                 min_free = i;
 646         }
 647         if (min_free == -1) {
 648             struct descr *tmp;
 649             tmp = realloc(d, (ndescr + 4) * sizeof(*d));
 650             if(tmp == NULL)
 651                 krb5_warnx(kcm_context, "No memory");
 652             else {
 653                 d = tmp;
 654                 reinit_descrs (d, ndescr);
 655                 memset(d + ndescr, 0, 4 * sizeof(*d));
 656                 for(i = ndescr; i < ndescr + 4; i++)
 657                     init_descr (&d[i]);
 658                 min_free = ndescr;
 659                 ndescr += 4;
 660             }
 661         }
 662
 663         tmout.tv_sec = STREAM_TIMEOUT;
 664         tmout.tv_usec = 0;
 665         switch (select(max_fd + 1, &fds, 0, 0, &tmout)){
 666         case 0:
 667             kcm_run_events(kcm_context, time(NULL));
 668             break;
 669         case -1:
 670             if (errno != EINTR)
 671                 krb5_warn(kcm_context, errno, "select");
 672             break;
 673         default:
 674             for(i = 0; i < ndescr; i++) {
 675                 if(d[i].s >= 0 && FD_ISSET(d[i].s, &fds)) {
 676                     if (d[i].type == SOCK_STREAM)
 677                         handle_stream(d, i, min_free);
 678                 }
 679             }
 680             kcm_run_events(kcm_context, time(NULL));
 681             break;
 682         }
 683     }
 684     if (d->path != NULL)
 685         unlink(d->path);
 686     free(d);
 687 }
 688