bsd/kern/kpi_socketfilter.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_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 License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <sys/kpi_socketfilter.h>
  30
  31 #include <sys/socket.h>
  32 #include <sys/param.h>
  33 #include <sys/errno.h>
  34 #include <sys/malloc.h>
  35 #include <sys/protosw.h>
  36 #include <kern/locks.h>
  37 #include <net/kext_net.h>
  38
  39 static struct socket_filter_list        sock_filter_head;
  40 static lck_mtx_t                                        *sock_filter_lock = 0;
  41
  42 static void     sflt_detach_private(struct socket_filter_entry *entry, int unregistering);
  43
  44 __private_extern__ void
  45 sflt_init(void)
  46 {
  47         lck_grp_attr_t  *grp_attrib = 0;
  48         lck_attr_t              *lck_attrib = 0;
  49         lck_grp_t               *lck_group = 0;
  50
  51         TAILQ_INIT(&sock_filter_head);
  52
  53         /* Allocate a spin lock */
  54         grp_attrib = lck_grp_attr_alloc_init();
  55         lck_grp_attr_setdefault(grp_attrib);
  56         lck_group = lck_grp_alloc_init("socket filter lock", grp_attrib);
  57         lck_grp_attr_free(grp_attrib);
  58         lck_attrib = lck_attr_alloc_init();
  59         lck_attr_setdefault(lck_attrib);
  60         lck_attr_setdebug(lck_attrib);
  61         sock_filter_lock = lck_mtx_alloc_init(lck_group, lck_attrib);
  62         lck_grp_free(lck_group);
  63         lck_attr_free(lck_attrib);
  64 }
  65
  66 __private_extern__ void
  67 sflt_initsock(
  68         struct socket *so)
  69 {
  70         struct protosw *proto = so->so_proto;
  71         struct socket_filter *filter;
  72
  73         if (TAILQ_FIRST(&proto->pr_filter_head) != NULL) {
  74                 lck_mtx_lock(sock_filter_lock);
  75                 TAILQ_FOREACH(filter, &proto->pr_filter_head, sf_protosw_next) {
  76                         sflt_attach_private(so, filter, 0, 0);
  77                 }
  78                 lck_mtx_unlock(sock_filter_lock);
  79         }
  80 }
  81
  82 __private_extern__ void
  83 sflt_termsock(
  84         struct socket *so)
  85 {
  86         struct socket_filter_entry *filter;
  87         struct socket_filter_entry *filter_next;
  88
  89         for (filter = so->so_filt; filter; filter = filter_next) {
  90                 filter_next = filter->sfe_next_onsocket;
  91                 sflt_detach_private(filter, 0);
  92         }
  93         so->so_filt = NULL;
  94 }
  95
  96 __private_extern__ void
  97 sflt_use(
  98         struct socket *so)
  99 {
 100         so->so_filteruse++;
 101 }
 102
 103 __private_extern__ void
 104 sflt_unuse(
 105         struct socket *so)
 106 {
 107         so->so_filteruse--;
 108         if (so->so_filteruse == 0) {
 109                 struct socket_filter_entry *filter;
 110                 struct socket_filter_entry *next_filter;
 111                 // search for detaching filters
 112                 for (filter = so->so_filt; filter; filter = next_filter) {
 113                         next_filter = filter->sfe_next_onsocket;
 114
 115                         if (filter->sfe_flags & SFEF_DETACHUSEZERO) {
 116                                 sflt_detach_private(filter, 0);
 117                         }
 118                 }
 119         }
 120 }
 121
 122 __private_extern__ void
 123 sflt_notify(
 124         struct socket   *so,
 125         sflt_event_t    event,
 126         void                    *param)
 127 {
 128         struct socket_filter_entry      *filter;
 129         int                                                     filtered = 0;
 130
 131         for (filter = so->so_filt; filter;
 132                  filter = filter->sfe_next_onsocket) {
 133                 if (filter->sfe_filter->sf_filter.sf_notify) {
 134                         if (filtered == 0) {
 135                                 filtered = 1;
 136                                 sflt_use(so);
 137                                 socket_unlock(so, 0);
 138                         }
 139                         filter->sfe_filter->sf_filter.sf_notify(
 140                                 filter->sfe_cookie, so, event, param);
 141                 }
 142         }
 143
 144         if (filtered != 0) {
 145                 socket_lock(so, 0);
 146                 sflt_unuse(so);
 147         }
 148 }
 149
 150 __private_extern__ int
 151 sflt_data_in(
 152         struct socket                   *so,
 153         const struct sockaddr   *from,
 154         mbuf_t                                  *data,
 155         mbuf_t                                  *control,
 156         sflt_data_flag_t                flags,
 157         int                                             *filtered)
 158 {
 159         struct socket_filter_entry      *filter;
 160         int                                                     error = 0;
 161         int                                                     filtered_storage;
 162
 163         if (filtered == NULL)
 164                 filtered = &filtered_storage;
 165         *filtered = 0;
 166
 167         for (filter = so->so_filt; filter && (error == 0);
 168                  filter = filter->sfe_next_onsocket) {
 169                 if (filter->sfe_filter->sf_filter.sf_data_in) {
 170                         if (*filtered == 0) {
 171                                 *filtered = 1;
 172                                 sflt_use(so);
 173                                 socket_unlock(so, 0);
 174                         }
 175                         error = filter->sfe_filter->sf_filter.sf_data_in(
 176                                                 filter->sfe_cookie, so, from, data, control, flags);
 177                 }
 178         }
 179
 180         if (*filtered != 0) {
 181                 socket_lock(so, 0);
 182                 sflt_unuse(so);
 183         }
 184
 185         return error;
 186 }
 187
 188 /* sflt_attach_private
 189  *
 190  * Assumptions: If filter is not NULL, socket_filter_lock is held.
 191  */
 192
 193 __private_extern__ int
 194 sflt_attach_private(
 195         struct socket *so,
 196         struct socket_filter *filter,
 197         sflt_handle                     handle,
 198         int sock_locked)
 199 {
 200         struct socket_filter_entry *entry = NULL;
 201         int didlock = 0;
 202         int error = 0;
 203
 204         if (filter == NULL) {
 205                 /* Find the filter by the handle */
 206                 lck_mtx_lock(sock_filter_lock);
 207                 didlock = 1;
 208
 209                 TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 210                         if (filter->sf_filter.sf_handle == handle)
 211                                 break;
 212                 }
 213         }
 214
 215         if (filter == NULL)
 216                 error = ENOENT;
 217
 218         if (error == 0) {
 219                 /* allocate the socket filter entry */
 220                 MALLOC(entry, struct socket_filter_entry *, sizeof(*entry), M_IFADDR, M_WAITOK);
 221                 if (entry == NULL) {
 222                         error = ENOMEM;
 223                 }
 224         }
 225
 226         if (error == 0) {
 227                 /* Initialize the socket filter entry and call the attach function */
 228                 entry->sfe_filter = filter;
 229                 entry->sfe_socket = so;
 230                 entry->sfe_cookie = NULL;
 231                 entry->sfe_flags = 0;
 232                 if (entry->sfe_filter->sf_filter.sf_attach) {
 233                         filter->sf_usecount++;
 234
 235                         if (sock_locked)
 236                                 socket_unlock(so, 0);
 237                         error = entry->sfe_filter->sf_filter.sf_attach(&entry->sfe_cookie, so);
 238                         if (sock_locked)
 239                                 socket_lock(so, 0);
 240
 241                         filter->sf_usecount--;
 242
 243                         /* If the attach function returns an error, this filter is not attached */
 244                         if (error) {
 245                                 FREE(entry, M_IFADDR);
 246                                 entry = NULL;
 247                         }
 248                 }
 249         }
 250
 251         if (error == 0) {
 252                 /* Put the entry in the socket list */
 253                 entry->sfe_next_onsocket = so->so_filt;
 254                 so->so_filt = entry;
 255
 256                 /* Put the entry in the filter list */
 257                 entry->sfe_next_onfilter = filter->sf_entry_head;
 258                 filter->sf_entry_head = entry;
 259
 260                 /* Incremenet the parent filter's usecount */
 261                 filter->sf_usecount++;
 262         }
 263
 264         if (didlock) {
 265                 lck_mtx_unlock(sock_filter_lock);
 266         }
 267
 268         return error;
 269 }
 270
 271
 272 /* sflt_detach_private
 273  *
 274  * Assumptions: if you pass 0 in for the second parameter, you are holding the
 275  * socket lock for the socket the entry is attached to. If you pass 1 in for
 276  * the second parameter, it is assumed that the entry is not on the filter's
 277  * list and the socket lock is not held.
 278  */
 279
 280 static void
 281 sflt_detach_private(
 282         struct socket_filter_entry *entry,
 283         int     unregistering)
 284 {
 285         struct socket *so = entry->sfe_socket;
 286         struct socket_filter_entry **next_ptr;
 287         int                             detached = 0;
 288         int                             found = 0;
 289
 290         if (unregistering) {
 291                 socket_lock(entry->sfe_socket, 0);
 292         }
 293
 294         /*
 295          * Attempt to find the entry on the filter's list and
 296          * remove it. This prevents a filter detaching at the
 297          * same time from attempting to remove the same entry.
 298          */
 299         lck_mtx_lock(sock_filter_lock);
 300         if (!unregistering) {
 301                 if ((entry->sfe_flags & SFEF_UNREGISTERING) != 0) {
 302                         /*
 303                          * Another thread is unregistering the filter, we need to
 304                          * avoid detaching the filter here so the socket won't go
 305                          * away.
 306                          */
 307                         lck_mtx_unlock(sock_filter_lock);
 308                         return;
 309                 }
 310                 for (next_ptr = &entry->sfe_filter->sf_entry_head; *next_ptr;
 311                          next_ptr = &((*next_ptr)->sfe_next_onfilter)) {
 312                         if (*next_ptr == entry) {
 313                                 found = 1;
 314                                 *next_ptr = entry->sfe_next_onfilter;
 315                                 break;
 316                         }
 317                 }
 318
 319                 if (!found && (entry->sfe_flags & SFEF_DETACHUSEZERO) == 0) {
 320                         lck_mtx_unlock(sock_filter_lock);
 321                         return;
 322                 }
 323         }
 324         else {
 325                 /*
 326                  * Clear the removing flag. We will perform the detach here or
 327                  * request a delayed deatch.
 328                  */
 329                 entry->sfe_flags &= ~SFEF_UNREGISTERING;
 330         }
 331
 332         if (entry->sfe_socket->so_filteruse != 0) {
 333                 entry->sfe_flags |= SFEF_DETACHUSEZERO;
 334                 lck_mtx_unlock(sock_filter_lock);
 335                 return;
 336         }
 337         else {
 338                 /*
 339                  * Check if we are removing the last attached filter and
 340                  * the parent filter is being unregistered.
 341                  */
 342                 entry->sfe_filter->sf_usecount--;
 343                 if ((entry->sfe_filter->sf_usecount == 0) &&
 344                         (entry->sfe_filter->sf_flags & SFF_DETACHING) != 0)
 345                         detached = 1;
 346         }
 347         lck_mtx_unlock(sock_filter_lock);
 348
 349         /* Remove from the socket list */
 350         for (next_ptr = &entry->sfe_socket->so_filt; *next_ptr;
 351                  next_ptr = &((*next_ptr)->sfe_next_onsocket)) {
 352                 if (*next_ptr == entry) {
 353                         *next_ptr = entry->sfe_next_onsocket;
 354                         break;
 355                 }
 356         }
 357
 358         if (entry->sfe_filter->sf_filter.sf_detach)
 359                 entry->sfe_filter->sf_filter.sf_detach(entry->sfe_cookie, entry->sfe_socket);
 360
 361         if (detached && entry->sfe_filter->sf_filter.sf_unregistered) {
 362                 entry->sfe_filter->sf_filter.sf_unregistered(entry->sfe_filter->sf_filter.sf_handle);
 363                 FREE(entry->sfe_filter, M_IFADDR);
 364         }
 365
 366         if (unregistering)
 367                 socket_unlock(entry->sfe_socket, 1);
 368
 369         FREE(entry, M_IFADDR);
 370 }
 371
 372 errno_t
 373 sflt_attach(
 374         socket_t        socket,
 375         sflt_handle     handle)
 376 {
 377         if (socket == NULL || handle == 0)
 378                 return EINVAL;
 379
 380         return sflt_attach_private(socket, NULL, handle, 0);
 381 }
 382
 383 errno_t
 384 sflt_detach(
 385         socket_t        socket,
 386         sflt_handle     handle)
 387 {
 388         struct socket_filter_entry      *filter;
 389         errno_t result = 0;
 390
 391         if (socket == NULL || handle == 0)
 392                 return EINVAL;
 393
 394         socket_lock(socket, 1);
 395
 396         for (filter = socket->so_filt; filter;
 397                  filter = filter->sfe_next_onsocket) {
 398                 if (filter->sfe_filter->sf_filter.sf_handle == handle)
 399                         break;
 400         }
 401
 402         if (filter != NULL) {
 403                 sflt_detach_private(filter, 0);
 404         }
 405         else {
 406                 socket->so_filt = NULL;
 407                 result = ENOENT;
 408         }
 409
 410         socket_unlock(socket, 1);
 411
 412         return result;
 413 }
 414
 415
 416 errno_t
 417 sflt_register(
 418         const struct sflt_filter        *filter,
 419         int                                                     domain,
 420         int                                                     type,
 421         int                                                     protocol)
 422 {
 423         struct socket_filter *sock_filt = NULL;
 424         struct socket_filter *match = NULL;
 425         int error = 0;
 426         struct protosw *pr = pffindproto(domain, protocol, type);
 427
 428         if (pr == NULL) return ENOENT;
 429
 430         if (filter->sf_attach == NULL || filter->sf_detach == NULL) return EINVAL;
 431         if (filter->sf_handle == 0) return EINVAL;
 432         if (filter->sf_name == NULL) return EINVAL;
 433
 434         /* Allocate the socket filter */
 435         MALLOC(sock_filt, struct socket_filter*, sizeof(*sock_filt), M_IFADDR, M_WAITOK);
 436         if (sock_filt == NULL) {
 437                 return ENOBUFS;
 438         }
 439
 440         bzero(sock_filt, sizeof(*sock_filt));
 441         sock_filt->sf_filter = *filter;
 442
 443         lck_mtx_lock(sock_filter_lock);
 444         /* Look for an existing entry */
 445         TAILQ_FOREACH(match, &sock_filter_head, sf_global_next) {
 446                 if (match->sf_filter.sf_handle == sock_filt->sf_filter.sf_handle) {
 447                         break;
 448                 }
 449         }
 450
 451         /* Add the entry only if there was no existing entry */
 452         if (match == NULL) {
 453                 TAILQ_INSERT_TAIL(&sock_filter_head, sock_filt, sf_global_next);
 454                 if ((sock_filt->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 455                         TAILQ_INSERT_TAIL(&pr->pr_filter_head, sock_filt, sf_protosw_next);
 456                         sock_filt->sf_proto = pr;
 457                 }
 458         }
 459         lck_mtx_unlock(sock_filter_lock);
 460
 461         if (match != NULL) {
 462                 FREE(sock_filt, M_IFADDR);
 463                 return EEXIST;
 464         }
 465
 466         return error;
 467 }
 468
 469 errno_t
 470 sflt_unregister(
 471         sflt_handle handle)
 472 {
 473         struct socket_filter *filter;
 474         struct socket_filter_entry *entry_head = NULL;
 475         struct socket_filter_entry *next_entry = NULL;
 476
 477         /* Find the entry and remove it from the global and protosw lists */
 478         lck_mtx_lock(sock_filter_lock);
 479         TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 480                 if (filter->sf_filter.sf_handle == handle)
 481                         break;
 482         }
 483
 484         if (filter) {
 485                 TAILQ_REMOVE(&sock_filter_head, filter, sf_global_next);
 486                 if ((filter->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 487                         TAILQ_REMOVE(&filter->sf_proto->pr_filter_head, filter, sf_protosw_next);
 488                 }
 489                 entry_head = filter->sf_entry_head;
 490                 filter->sf_entry_head = NULL;
 491                 filter->sf_flags |= SFF_DETACHING;
 492
 493                 for (next_entry = entry_head; next_entry;
 494                          next_entry = next_entry->sfe_next_onfilter) {
 495                         socket_lock(next_entry->sfe_socket, 1);
 496                         next_entry->sfe_flags |= SFEF_UNREGISTERING;
 497                         socket_unlock(next_entry->sfe_socket, 0);       /* Radar 4201550: prevents the socket from being deleted while being unregistered */
 498                 }
 499         }
 500
 501         lck_mtx_unlock(sock_filter_lock);
 502
 503         if (filter == NULL)
 504                 return ENOENT;
 505
 506         /* We need to detach the filter from any sockets it's attached to */
 507         if (entry_head == 0) {
 508                 if (filter->sf_filter.sf_unregistered)
 509                         filter->sf_filter.sf_unregistered(filter->sf_filter.sf_handle);
 510         } else {
 511                 while (entry_head) {
 512                         next_entry = entry_head->sfe_next_onfilter;
 513                         sflt_detach_private(entry_head, 1);
 514                         entry_head = next_entry;
 515                 }
 516         }
 517
 518         return 0;
 519 }
 520
 521 errno_t
 522 sock_inject_data_in(
 523         socket_t so,
 524         const struct sockaddr* from,
 525         mbuf_t data,
 526         mbuf_t control,
 527         sflt_data_flag_t flags)
 528 {
 529         int error = 0;
 530         if (so == NULL || data == NULL) return EINVAL;
 531
 532         if (flags & sock_data_filt_flag_oob) {
 533                 return ENOTSUP;
 534         }
 535
 536         socket_lock(so, 1);
 537
 538         if (from) {
 539                 if (sbappendaddr(&so->so_rcv, (struct sockaddr*)from, data,
 540                                                  control, NULL))
 541                         sorwakeup(so);
 542                 goto done;
 543         }
 544
 545         if (control) {
 546                 if (sbappendcontrol(&so->so_rcv, data, control, NULL))
 547                         sorwakeup(so);
 548                 goto done;
 549         }
 550
 551         if (flags & sock_data_filt_flag_record) {
 552                 if (control || from) {
 553                         error = EINVAL;
 554                         goto done;
 555                 }
 556                 if (sbappendrecord(&so->so_rcv, (struct mbuf*)data))
 557                         sorwakeup(so);
 558                 goto done;
 559         }
 560
 561         if (sbappend(&so->so_rcv, data))
 562                 sorwakeup(so);
 563 done:
 564         socket_unlock(so, 1);
 565         return error;
 566 }
 567
 568 errno_t
 569 sock_inject_data_out(
 570         socket_t so,
 571         const struct sockaddr* to,
 572         mbuf_t data,
 573         mbuf_t control,
 574         sflt_data_flag_t flags)
 575 {
 576         int     sosendflags = 0;
 577         if (flags & sock_data_filt_flag_oob) sosendflags = MSG_OOB;
 578         return sosend(so, (const struct sockaddr*)to, NULL,
 579                                   data, control, sosendflags);
 580 }
 581
 582 sockopt_dir
 583 sockopt_direction(
 584         sockopt_t       sopt)
 585 {
 586         return (sopt->sopt_dir == SOPT_GET) ? sockopt_get : sockopt_set;
 587 }
 588
 589 int
 590 sockopt_level(
 591         sockopt_t       sopt)
 592 {
 593         return sopt->sopt_level;
 594 }
 595
 596 int
 597 sockopt_name(
 598         sockopt_t       sopt)
 599 {
 600         return sopt->sopt_name;
 601 }
 602
 603 size_t
 604 sockopt_valsize(
 605         sockopt_t       sopt)
 606 {
 607         return sopt->sopt_valsize;
 608 }
 609
 610 errno_t
 611 sockopt_copyin(
 612         sockopt_t       sopt,
 613         void *data,
 614         size_t  len)
 615 {
 616         return sooptcopyin(sopt, data, len, len);
 617 }
 618
 619 errno_t
 620 sockopt_copyout(
 621         sockopt_t       sopt,
 622         void *data,
 623         size_t  len)
 624 {
 625         return sooptcopyout(sopt, data, len);
 626 }