bsd/kern/kpi_socketfilter.c

   1 /*
   2  * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 #include <sys/kpi_socketfilter.h>
  32
  33 #include <sys/socket.h>
  34 #include <sys/param.h>
  35 #include <sys/errno.h>
  36 #include <sys/malloc.h>
  37 #include <sys/protosw.h>
  38 #include <kern/locks.h>
  39 #include <net/kext_net.h>
  40
  41 static struct socket_filter_list        sock_filter_head;
  42 static lck_mtx_t                                        *sock_filter_lock = 0;
  43
  44 static void     sflt_detach_private(struct socket_filter_entry *entry, int unregistering);
  45
  46 __private_extern__ void
  47 sflt_init(void)
  48 {
  49         lck_grp_attr_t  *grp_attrib = 0;
  50         lck_attr_t              *lck_attrib = 0;
  51         lck_grp_t               *lck_group = 0;
  52
  53         TAILQ_INIT(&sock_filter_head);
  54
  55         /* Allocate a spin lock */
  56         grp_attrib = lck_grp_attr_alloc_init();
  57         lck_grp_attr_setdefault(grp_attrib);
  58         lck_group = lck_grp_alloc_init("socket filter lock", grp_attrib);
  59         lck_grp_attr_free(grp_attrib);
  60         lck_attrib = lck_attr_alloc_init();
  61         lck_attr_setdefault(lck_attrib);
  62         lck_attr_setdebug(lck_attrib);
  63         sock_filter_lock = lck_mtx_alloc_init(lck_group, lck_attrib);
  64         lck_grp_free(lck_group);
  65         lck_attr_free(lck_attrib);
  66 }
  67
  68 __private_extern__ void
  69 sflt_initsock(
  70         struct socket *so)
  71 {
  72         struct protosw *proto = so->so_proto;
  73         struct socket_filter *filter;
  74
  75         if (TAILQ_FIRST(&proto->pr_filter_head) != NULL) {
  76                 lck_mtx_lock(sock_filter_lock);
  77                 TAILQ_FOREACH(filter, &proto->pr_filter_head, sf_protosw_next) {
  78                         sflt_attach_private(so, filter, 0, 0);
  79                 }
  80                 lck_mtx_unlock(sock_filter_lock);
  81         }
  82 }
  83
  84 __private_extern__ void
  85 sflt_termsock(
  86         struct socket *so)
  87 {
  88         struct socket_filter_entry *filter;
  89         struct socket_filter_entry *filter_next;
  90
  91         for (filter = so->so_filt; filter; filter = filter_next) {
  92                 filter_next = filter->sfe_next_onsocket;
  93                 sflt_detach_private(filter, 0);
  94         }
  95         so->so_filt = NULL;
  96 }
  97
  98 __private_extern__ void
  99 sflt_use(
 100         struct socket *so)
 101 {
 102         so->so_filteruse++;
 103 }
 104
 105 __private_extern__ void
 106 sflt_unuse(
 107         struct socket *so)
 108 {
 109         so->so_filteruse--;
 110         if (so->so_filteruse == 0) {
 111                 struct socket_filter_entry *filter;
 112                 struct socket_filter_entry *next_filter;
 113                 // search for detaching filters
 114                 for (filter = so->so_filt; filter; filter = next_filter) {
 115                         next_filter = filter->sfe_next_onsocket;
 116
 117                         if (filter->sfe_flags & SFEF_DETACHUSEZERO) {
 118                                 sflt_detach_private(filter, 0);
 119                         }
 120                 }
 121         }
 122 }
 123
 124 __private_extern__ void
 125 sflt_notify(
 126         struct socket   *so,
 127         sflt_event_t    event,
 128         void                    *param)
 129 {
 130         struct socket_filter_entry      *filter;
 131         int                                                     filtered = 0;
 132
 133         for (filter = so->so_filt; filter;
 134                  filter = filter->sfe_next_onsocket) {
 135                 if (filter->sfe_filter->sf_filter.sf_notify) {
 136                         if (filtered == 0) {
 137                                 filtered = 1;
 138                                 sflt_use(so);
 139                                 socket_unlock(so, 0);
 140                         }
 141                         filter->sfe_filter->sf_filter.sf_notify(
 142                                 filter->sfe_cookie, so, event, param);
 143                 }
 144         }
 145
 146         if (filtered != 0) {
 147                 socket_lock(so, 0);
 148                 sflt_unuse(so);
 149         }
 150 }
 151
 152 __private_extern__ int
 153 sflt_data_in(
 154         struct socket                   *so,
 155         const struct sockaddr   *from,
 156         mbuf_t                                  *data,
 157         mbuf_t                                  *control,
 158         sflt_data_flag_t                flags,
 159         int                                             *filtered)
 160 {
 161         struct socket_filter_entry      *filter;
 162         int                                                     error = 0;
 163         int                                                     filtered_storage;
 164
 165         if (filtered == NULL)
 166                 filtered = &filtered_storage;
 167         *filtered = 0;
 168
 169         for (filter = so->so_filt; filter && (error == 0);
 170                  filter = filter->sfe_next_onsocket) {
 171                 if (filter->sfe_filter->sf_filter.sf_data_in) {
 172                         if (*filtered == 0) {
 173                                 *filtered = 1;
 174                                 sflt_use(so);
 175                                 socket_unlock(so, 0);
 176                         }
 177                         error = filter->sfe_filter->sf_filter.sf_data_in(
 178                                                 filter->sfe_cookie, so, from, data, control, flags);
 179                 }
 180         }
 181
 182         if (*filtered != 0) {
 183                 socket_lock(so, 0);
 184                 sflt_unuse(so);
 185         }
 186
 187         return error;
 188 }
 189
 190 /* sflt_attach_private
 191  *
 192  * Assumptions: If filter is not NULL, socket_filter_lock is held.
 193  */
 194
 195 __private_extern__ int
 196 sflt_attach_private(
 197         struct socket *so,
 198         struct socket_filter *filter,
 199         sflt_handle                     handle,
 200         int sock_locked)
 201 {
 202         struct socket_filter_entry *entry = NULL;
 203         int didlock = 0;
 204         int error = 0;
 205
 206         if (filter == NULL) {
 207                 /* Find the filter by the handle */
 208                 lck_mtx_lock(sock_filter_lock);
 209                 didlock = 1;
 210
 211                 TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 212                         if (filter->sf_filter.sf_handle == handle)
 213                                 break;
 214                 }
 215         }
 216
 217         if (filter == NULL)
 218                 error = ENOENT;
 219
 220         if (error == 0) {
 221                 /* allocate the socket filter entry */
 222                 MALLOC(entry, struct socket_filter_entry *, sizeof(*entry), M_IFADDR, M_WAITOK);
 223                 if (entry == NULL) {
 224                         error = ENOMEM;
 225                 }
 226         }
 227
 228         if (error == 0) {
 229                 /* Initialize the socket filter entry and call the attach function */
 230                 entry->sfe_filter = filter;
 231                 entry->sfe_socket = so;
 232                 entry->sfe_cookie = NULL;
 233                 entry->sfe_flags = 0;
 234                 if (entry->sfe_filter->sf_filter.sf_attach) {
 235                         filter->sf_usecount++;
 236
 237                         if (sock_locked)
 238                                 socket_unlock(so, 0);
 239                         error = entry->sfe_filter->sf_filter.sf_attach(&entry->sfe_cookie, so);
 240                         if (sock_locked)
 241                                 socket_lock(so, 0);
 242
 243                         filter->sf_usecount--;
 244
 245                         /* If the attach function returns an error, this filter is not attached */
 246                         if (error) {
 247                                 FREE(entry, M_IFADDR);
 248                                 entry = NULL;
 249                         }
 250                 }
 251         }
 252
 253         if (error == 0) {
 254                 /* Put the entry in the socket list */
 255                 entry->sfe_next_onsocket = so->so_filt;
 256                 so->so_filt = entry;
 257
 258                 /* Put the entry in the filter list */
 259                 entry->sfe_next_onfilter = filter->sf_entry_head;
 260                 filter->sf_entry_head = entry;
 261
 262                 /* Incremenet the parent filter's usecount */
 263                 filter->sf_usecount++;
 264         }
 265
 266         if (didlock) {
 267                 lck_mtx_unlock(sock_filter_lock);
 268         }
 269
 270         return error;
 271 }
 272
 273
 274 /* sflt_detach_private
 275  *
 276  * Assumptions: if you pass 0 in for the second parameter, you are holding the
 277  * socket lock for the socket the entry is attached to. If you pass 1 in for
 278  * the second parameter, it is assumed that the entry is not on the filter's
 279  * list and the socket lock is not held.
 280  */
 281
 282 static void
 283 sflt_detach_private(
 284         struct socket_filter_entry *entry,
 285         int     unregistering)
 286 {
 287         struct socket *so = entry->sfe_socket;
 288         struct socket_filter_entry **next_ptr;
 289         int                             detached = 0;
 290         int                             found = 0;
 291
 292         if (unregistering) {
 293                 socket_lock(entry->sfe_socket, 0);
 294         }
 295
 296         /*
 297          * Attempt to find the entry on the filter's list and
 298          * remove it. This prevents a filter detaching at the
 299          * same time from attempting to remove the same entry.
 300          */
 301         lck_mtx_lock(sock_filter_lock);
 302         if (!unregistering) {
 303                 if ((entry->sfe_flags & SFEF_UNREGISTERING) != 0) {
 304                         /*
 305                          * Another thread is unregistering the filter, we need to
 306                          * avoid detaching the filter here so the socket won't go
 307                          * away.
 308                          */
 309                         lck_mtx_unlock(sock_filter_lock);
 310                         return;
 311                 }
 312                 for (next_ptr = &entry->sfe_filter->sf_entry_head; *next_ptr;
 313                          next_ptr = &((*next_ptr)->sfe_next_onfilter)) {
 314                         if (*next_ptr == entry) {
 315                                 found = 1;
 316                                 *next_ptr = entry->sfe_next_onfilter;
 317                                 break;
 318                         }
 319                 }
 320
 321                 if (!found && (entry->sfe_flags & SFEF_DETACHUSEZERO) == 0) {
 322                         lck_mtx_unlock(sock_filter_lock);
 323                         return;
 324                 }
 325         }
 326         else {
 327                 /*
 328                  * Clear the removing flag. We will perform the detach here or
 329                  * request a delayed deatch.
 330                  */
 331                 entry->sfe_flags &= ~SFEF_UNREGISTERING;
 332         }
 333
 334         if (entry->sfe_socket->so_filteruse != 0) {
 335                 entry->sfe_flags |= SFEF_DETACHUSEZERO;
 336                 lck_mtx_unlock(sock_filter_lock);
 337                 return;
 338         }
 339         else {
 340                 /*
 341                  * Check if we are removing the last attached filter and
 342                  * the parent filter is being unregistered.
 343                  */
 344                 entry->sfe_filter->sf_usecount--;
 345                 if ((entry->sfe_filter->sf_usecount == 0) &&
 346                         (entry->sfe_filter->sf_flags & SFF_DETACHING) != 0)
 347                         detached = 1;
 348         }
 349         lck_mtx_unlock(sock_filter_lock);
 350
 351         /* Remove from the socket list */
 352         for (next_ptr = &entry->sfe_socket->so_filt; *next_ptr;
 353                  next_ptr = &((*next_ptr)->sfe_next_onsocket)) {
 354                 if (*next_ptr == entry) {
 355                         *next_ptr = entry->sfe_next_onsocket;
 356                         break;
 357                 }
 358         }
 359
 360         if (entry->sfe_filter->sf_filter.sf_detach)
 361                 entry->sfe_filter->sf_filter.sf_detach(entry->sfe_cookie, entry->sfe_socket);
 362
 363         if (detached && entry->sfe_filter->sf_filter.sf_unregistered) {
 364                 entry->sfe_filter->sf_filter.sf_unregistered(entry->sfe_filter->sf_filter.sf_handle);
 365                 FREE(entry->sfe_filter, M_IFADDR);
 366         }
 367
 368         if (unregistering)
 369                 socket_unlock(entry->sfe_socket, 1);
 370
 371         FREE(entry, M_IFADDR);
 372 }
 373
 374 errno_t
 375 sflt_attach(
 376         socket_t        socket,
 377         sflt_handle     handle)
 378 {
 379         if (socket == NULL || handle == 0)
 380                 return EINVAL;
 381
 382         return sflt_attach_private(socket, NULL, handle, 0);
 383 }
 384
 385 errno_t
 386 sflt_detach(
 387         socket_t        socket,
 388         sflt_handle     handle)
 389 {
 390         struct socket_filter_entry      *filter;
 391         errno_t result = 0;
 392
 393         if (socket == NULL || handle == 0)
 394                 return EINVAL;
 395
 396         socket_lock(socket, 1);
 397
 398         for (filter = socket->so_filt; filter;
 399                  filter = filter->sfe_next_onsocket) {
 400                 if (filter->sfe_filter->sf_filter.sf_handle == handle)
 401                         break;
 402         }
 403
 404         if (filter != NULL) {
 405                 sflt_detach_private(filter, 0);
 406         }
 407         else {
 408                 socket->so_filt = NULL;
 409                 result = ENOENT;
 410         }
 411
 412         socket_unlock(socket, 1);
 413
 414         return result;
 415 }
 416
 417
 418 errno_t
 419 sflt_register(
 420         const struct sflt_filter        *filter,
 421         int                                                     domain,
 422         int                                                     type,
 423         int                                                     protocol)
 424 {
 425         struct socket_filter *sock_filt = NULL;
 426         struct socket_filter *match = NULL;
 427         int error = 0;
 428         struct protosw *pr = pffindproto(domain, protocol, type);
 429
 430         if (pr == NULL) return ENOENT;
 431
 432         if (filter->sf_attach == NULL || filter->sf_detach == NULL) return EINVAL;
 433         if (filter->sf_handle == 0) return EINVAL;
 434         if (filter->sf_name == NULL) return EINVAL;
 435
 436         /* Allocate the socket filter */
 437         MALLOC(sock_filt, struct socket_filter*, sizeof(*sock_filt), M_IFADDR, M_WAITOK);
 438         if (sock_filt == NULL) {
 439                 return ENOBUFS;
 440         }
 441
 442         bzero(sock_filt, sizeof(*sock_filt));
 443         sock_filt->sf_filter = *filter;
 444
 445         lck_mtx_lock(sock_filter_lock);
 446         /* Look for an existing entry */
 447         TAILQ_FOREACH(match, &sock_filter_head, sf_global_next) {
 448                 if (match->sf_filter.sf_handle == sock_filt->sf_filter.sf_handle) {
 449                         break;
 450                 }
 451         }
 452
 453         /* Add the entry only if there was no existing entry */
 454         if (match == NULL) {
 455                 TAILQ_INSERT_TAIL(&sock_filter_head, sock_filt, sf_global_next);
 456                 if ((sock_filt->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 457                         TAILQ_INSERT_TAIL(&pr->pr_filter_head, sock_filt, sf_protosw_next);
 458                         sock_filt->sf_proto = pr;
 459                 }
 460         }
 461         lck_mtx_unlock(sock_filter_lock);
 462
 463         if (match != NULL) {
 464                 FREE(sock_filt, M_IFADDR);
 465                 return EEXIST;
 466         }
 467
 468         return error;
 469 }
 470
 471 errno_t
 472 sflt_unregister(
 473         sflt_handle handle)
 474 {
 475         struct socket_filter *filter;
 476         struct socket_filter_entry *entry_head = NULL;
 477         struct socket_filter_entry *next_entry = NULL;
 478
 479         /* Find the entry and remove it from the global and protosw lists */
 480         lck_mtx_lock(sock_filter_lock);
 481         TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 482                 if (filter->sf_filter.sf_handle == handle)
 483                         break;
 484         }
 485
 486         if (filter) {
 487                 TAILQ_REMOVE(&sock_filter_head, filter, sf_global_next);
 488                 if ((filter->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 489                         TAILQ_REMOVE(&filter->sf_proto->pr_filter_head, filter, sf_protosw_next);
 490                 }
 491                 entry_head = filter->sf_entry_head;
 492                 filter->sf_entry_head = NULL;
 493                 filter->sf_flags |= SFF_DETACHING;
 494
 495                 for (next_entry = entry_head; next_entry;
 496                          next_entry = next_entry->sfe_next_onfilter) {
 497                         socket_lock(next_entry->sfe_socket, 1);
 498                         next_entry->sfe_flags |= SFEF_UNREGISTERING;
 499                         socket_unlock(next_entry->sfe_socket, 0);       /* Radar 4201550: prevents the socket from being deleted while being unregistered */
 500                 }
 501         }
 502
 503         lck_mtx_unlock(sock_filter_lock);
 504
 505         if (filter == NULL)
 506                 return ENOENT;
 507
 508         /* We need to detach the filter from any sockets it's attached to */
 509         if (entry_head == 0) {
 510                 if (filter->sf_filter.sf_unregistered)
 511                         filter->sf_filter.sf_unregistered(filter->sf_filter.sf_handle);
 512         } else {
 513                 while (entry_head) {
 514                         next_entry = entry_head->sfe_next_onfilter;
 515                         sflt_detach_private(entry_head, 1);
 516                         entry_head = next_entry;
 517                 }
 518         }
 519
 520         return 0;
 521 }
 522
 523 errno_t
 524 sock_inject_data_in(
 525         socket_t so,
 526         const struct sockaddr* from,
 527         mbuf_t data,
 528         mbuf_t control,
 529         sflt_data_flag_t flags)
 530 {
 531         int error = 0;
 532         if (so == NULL || data == NULL) return EINVAL;
 533
 534         if (flags & sock_data_filt_flag_oob) {
 535                 return ENOTSUP;
 536         }
 537
 538         socket_lock(so, 1);
 539
 540         if (from) {
 541                 if (sbappendaddr(&so->so_rcv, (struct sockaddr*)from, data,
 542                                                  control, NULL))
 543                         sorwakeup(so);
 544                 goto done;
 545         }
 546
 547         if (control) {
 548                 if (sbappendcontrol(&so->so_rcv, data, control, NULL))
 549                         sorwakeup(so);
 550                 goto done;
 551         }
 552
 553         if (flags & sock_data_filt_flag_record) {
 554                 if (control || from) {
 555                         error = EINVAL;
 556                         goto done;
 557                 }
 558                 if (sbappendrecord(&so->so_rcv, (struct mbuf*)data))
 559                         sorwakeup(so);
 560                 goto done;
 561         }
 562
 563         if (sbappend(&so->so_rcv, data))
 564                 sorwakeup(so);
 565 done:
 566         socket_unlock(so, 1);
 567         return error;
 568 }
 569
 570 errno_t
 571 sock_inject_data_out(
 572         socket_t so,
 573         const struct sockaddr* to,
 574         mbuf_t data,
 575         mbuf_t control,
 576         sflt_data_flag_t flags)
 577 {
 578         int     sosendflags = 0;
 579         if (flags & sock_data_filt_flag_oob) sosendflags = MSG_OOB;
 580         return sosend(so, (const struct sockaddr*)to, NULL,
 581                                   data, control, sosendflags);
 582 }
 583
 584 sockopt_dir
 585 sockopt_direction(
 586         sockopt_t       sopt)
 587 {
 588         return (sopt->sopt_dir == SOPT_GET) ? sockopt_get : sockopt_set;
 589 }
 590
 591 int
 592 sockopt_level(
 593         sockopt_t       sopt)
 594 {
 595         return sopt->sopt_level;
 596 }
 597
 598 int
 599 sockopt_name(
 600         sockopt_t       sopt)
 601 {
 602         return sopt->sopt_name;
 603 }
 604
 605 size_t
 606 sockopt_valsize(
 607         sockopt_t       sopt)
 608 {
 609         return sopt->sopt_valsize;
 610 }
 611
 612 errno_t
 613 sockopt_copyin(
 614         sockopt_t       sopt,
 615         void *data,
 616         size_t  len)
 617 {
 618         return sooptcopyin(sopt, data, len, len);
 619 }
 620
 621 errno_t
 622 sockopt_copyout(
 623         sockopt_t       sopt,
 624         void *data,
 625         size_t  len)
 626 {
 627         return sooptcopyout(sopt, data, len);
 628 }