osfmk/kern/exception.c

   1 /*
   2  * Copyright (c) 2000-2004 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  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58
  59 #include <mach/mach_types.h>
  60 #include <mach/boolean.h>
  61 #include <mach/kern_return.h>
  62 #include <mach/message.h>
  63 #include <mach/port.h>
  64 #include <mach/mig_errors.h>
  65 #include <mach/task.h>
  66 #include <mach/thread_status.h>
  67 #include <mach/exception_types.h>
  68 #include <mach/exc.h>
  69 #include <mach/mach_exc.h>
  70 #include <ipc/port.h>
  71 #include <ipc/ipc_entry.h>
  72 #include <ipc/ipc_object.h>
  73 #include <ipc/ipc_notify.h>
  74 #include <ipc/ipc_space.h>
  75 #include <ipc/ipc_pset.h>
  76 #include <ipc/ipc_machdep.h>
  77 #include <kern/counters.h>
  78 #include <kern/ipc_tt.h>
  79 #include <kern/task.h>
  80 #include <kern/thread.h>
  81 #include <kern/processor.h>
  82 #include <kern/sched.h>
  83 #include <kern/sched_prim.h>
  84 #include <kern/host.h>
  85 #include <kern/misc_protos.h>
  86 #include <security/mac_mach_internal.h>
  87 #include <string.h>
  88 #include <pexpert/pexpert.h>
  89
  90 extern int panic_on_exception_triage;
  91
  92 unsigned long c_thr_exc_raise = 0;
  93 unsigned long c_thr_exc_raise_state = 0;
  94 unsigned long c_thr_exc_raise_state_id = 0;
  95 unsigned long c_tsk_exc_raise = 0;
  96 unsigned long c_tsk_exc_raise_state = 0;
  97 unsigned long c_tsk_exc_raise_state_id = 0;
  98
  99 /* forward declarations */
 100 kern_return_t exception_deliver(
 101         thread_t                thread,
 102         exception_type_t        exception,
 103         mach_exception_data_t   code,
 104         mach_msg_type_number_t  codeCnt,
 105         struct exception_action *excp,
 106         lck_mtx_t                       *mutex);
 107
 108 static kern_return_t
 109 check_exc_receiver_dependency(
 110         exception_type_t exception,
 111         struct exception_action *excp,
 112         lck_mtx_t *mutex);
 113
 114 #ifdef MACH_BSD
 115 kern_return_t bsd_exception(
 116         exception_type_t        exception,
 117         mach_exception_data_t   code,
 118         mach_msg_type_number_t  codeCnt);
 119 #endif /* MACH_BSD */
 120
 121 /*
 122  *      Routine:        exception_deliver
 123  *      Purpose:
 124  *              Make an upcall to the exception server provided.
 125  *      Conditions:
 126  *              Nothing locked and no resources held.
 127  *              Called from an exception context, so
 128  *              thread_exception_return and thread_kdb_return
 129  *              are possible.
 130  *      Returns:
 131  *              KERN_SUCCESS if the exception was handled
 132  */
 133 kern_return_t
 134 exception_deliver(
 135         thread_t                thread,
 136         exception_type_t        exception,
 137         mach_exception_data_t   code,
 138         mach_msg_type_number_t  codeCnt,
 139         struct exception_action *excp,
 140         lck_mtx_t                       *mutex)
 141 {
 142         ipc_port_t              exc_port;
 143         exception_data_type_t   small_code[EXCEPTION_CODE_MAX];
 144         int                     code64;
 145         int                     behavior;
 146         int                     flavor;
 147         kern_return_t           kr;
 148         int use_fast_retrieve = TRUE;
 149         task_t task;
 150         ipc_port_t thread_port = NULL, task_port = NULL;
 151
 152         /*
 153          *  Save work if we are terminating.
 154          *  Just go back to our AST handler.
 155          */
 156         if (!thread->active && !thread->inspection)
 157                 return KERN_SUCCESS;
 158
 159         /*
 160          * If there are no exception actions defined for this entity,
 161          * we can't deliver here.
 162          */
 163         if (excp == NULL)
 164                 return KERN_FAILURE;
 165
 166         assert(exception < EXC_TYPES_COUNT);
 167         if (exception >= EXC_TYPES_COUNT)
 168                 return KERN_FAILURE;
 169
 170         excp = &excp[exception];
 171
 172         /*
 173          * Snapshot the exception action data under lock for consistency.
 174          * Hold a reference to the port over the exception_raise_* calls
 175          * so it can't be destroyed.  This seems like overkill, but keeps
 176          * the port from disappearing between now and when
 177          * ipc_object_copyin_from_kernel is finally called.
 178          */
 179         lck_mtx_lock(mutex);
 180         exc_port = excp->port;
 181         if (!IP_VALID(exc_port)) {
 182                 lck_mtx_unlock(mutex);
 183                 return KERN_FAILURE;
 184         }
 185         ip_lock(exc_port);
 186         if (!ip_active(exc_port)) {
 187                 ip_unlock(exc_port);
 188                 lck_mtx_unlock(mutex);
 189                 return KERN_FAILURE;
 190         }
 191         ip_reference(exc_port);
 192         exc_port->ip_srights++;
 193         ip_unlock(exc_port);
 194
 195         flavor = excp->flavor;
 196         behavior = excp->behavior;
 197         lck_mtx_unlock(mutex);
 198
 199         code64 = (behavior & MACH_EXCEPTION_CODES);
 200         behavior &= ~MACH_EXCEPTION_CODES;
 201
 202         if (!code64) {
 203                 small_code[0] = CAST_DOWN_EXPLICIT(exception_data_type_t, code[0]);
 204                 small_code[1] = CAST_DOWN_EXPLICIT(exception_data_type_t, code[1]);
 205         }
 206
 207         task = thread->task;
 208
 209 #if CONFIG_MACF
 210         /* Now is a reasonably good time to check if the exception action is
 211          * permitted for this process, because after this point we will send
 212          * the message out almost certainly.
 213          * As with other failures, exception_triage_thread will go on
 214          * to the next level.
 215          */
 216         if (mac_exc_action_check_exception_send(task, excp) != 0) {
 217                 return KERN_FAILURE;
 218         }
 219 #endif
 220
 221         if ((thread != current_thread() || exception == EXC_CORPSE_NOTIFY)
 222                         && behavior != EXCEPTION_STATE) {
 223                 use_fast_retrieve = FALSE;
 224
 225                 task_reference(task);
 226                 task_port = convert_task_to_port(task);
 227                 /* task ref consumed */
 228                 thread_reference(thread);
 229                 thread_port = convert_thread_to_port(thread);
 230                 /* thread ref consumed */
 231
 232         }
 233
 234         switch (behavior) {
 235         case EXCEPTION_STATE: {
 236                 mach_msg_type_number_t state_cnt;
 237                 thread_state_data_t state;
 238
 239                 c_thr_exc_raise_state++;
 240                 state_cnt = _MachineStateCount[flavor];
 241                 kr = thread_getstatus(thread, flavor,
 242                                       (thread_state_t)state,
 243                                       &state_cnt);
 244                 if (kr == KERN_SUCCESS) {
 245                         if (code64) {
 246                                 kr = mach_exception_raise_state(exc_port,
 247                                                 exception,
 248                                                 code,
 249                                                 codeCnt,
 250                                                 &flavor,
 251                                                 state, state_cnt,
 252                                                 state, &state_cnt);
 253                         } else {
 254                                 kr = exception_raise_state(exc_port, exception,
 255                                                 small_code,
 256                                                 codeCnt,
 257                                                 &flavor,
 258                                                 state, state_cnt,
 259                                                 state, &state_cnt);
 260                         }
 261                         if (kr == MACH_MSG_SUCCESS && exception != EXC_CORPSE_NOTIFY)
 262                                 kr = thread_setstatus(thread, flavor,
 263                                                 (thread_state_t)state,
 264                                                 state_cnt);
 265                 }
 266
 267                 return kr;
 268         }
 269
 270         case EXCEPTION_DEFAULT:
 271                 c_thr_exc_raise++;
 272                 if (code64) {
 273                         kr = mach_exception_raise(exc_port,
 274                                         use_fast_retrieve ? retrieve_thread_self_fast(thread) :
 275                                                 thread_port,
 276                                         use_fast_retrieve ? retrieve_task_self_fast(thread->task) :
 277                                                 task_port,
 278                                         exception,
 279                                         code,
 280                                         codeCnt);
 281                 } else {
 282                         kr = exception_raise(exc_port,
 283                                         use_fast_retrieve ? retrieve_thread_self_fast(thread) :
 284                                                 thread_port,
 285                                         use_fast_retrieve ? retrieve_task_self_fast(thread->task) :
 286                                                 task_port,
 287                                         exception,
 288                                         small_code,
 289                                         codeCnt);
 290                 }
 291
 292                 return kr;
 293
 294         case EXCEPTION_STATE_IDENTITY: {
 295                 mach_msg_type_number_t state_cnt;
 296                 thread_state_data_t state;
 297
 298                 c_thr_exc_raise_state_id++;
 299                 state_cnt = _MachineStateCount[flavor];
 300                 kr = thread_getstatus(thread, flavor,
 301                                       (thread_state_t)state,
 302                                       &state_cnt);
 303                 if (kr == KERN_SUCCESS) {
 304                         if (code64) {
 305                                 kr = mach_exception_raise_state_identity(
 306                                                 exc_port,
 307                                                 use_fast_retrieve ? retrieve_thread_self_fast(thread) :
 308                                                         thread_port,
 309                                                 use_fast_retrieve ? retrieve_task_self_fast(thread->task) :
 310                                                         task_port,
 311                                                 exception,
 312                                                 code,
 313                                                 codeCnt,
 314                                                 &flavor,
 315                                                 state, state_cnt,
 316                                                 state, &state_cnt);
 317                         } else {
 318                                 kr = exception_raise_state_identity(exc_port,
 319                                                 use_fast_retrieve ? retrieve_thread_self_fast(thread) :
 320                                                         thread_port,
 321                                                 use_fast_retrieve ? retrieve_task_self_fast(thread->task) :
 322                                                         task_port,
 323                                                 exception,
 324                                                 small_code,
 325                                                 codeCnt,
 326                                                 &flavor,
 327                                                 state, state_cnt,
 328                                                 state, &state_cnt);
 329                         }
 330                         if (kr == MACH_MSG_SUCCESS && exception != EXC_CORPSE_NOTIFY)
 331                                 kr = thread_setstatus(thread, flavor,
 332                                                 (thread_state_t)state,
 333                                                 state_cnt);
 334                 }
 335
 336                 return kr;
 337         }
 338
 339         default:
 340                panic ("bad exception behavior!");
 341                return KERN_FAILURE;
 342         }/* switch */
 343 }
 344
 345 /*
 346  * Routine: check_exc_receiver_dependency
 347  * Purpose:
 348  *      Verify that the port destined for receiving this exception is not
 349  *      on the current task. This would cause hang in kernel for
 350  *      EXC_CRASH primarily. Note: If port is transferred
 351  *      between check and delivery then deadlock may happen.
 352  *
 353  * Conditions:
 354  *              Nothing locked and no resources held.
 355  *              Called from an exception context.
 356  * Returns:
 357  *      KERN_SUCCESS if its ok to send exception message.
 358  */
 359 kern_return_t
 360 check_exc_receiver_dependency(
 361         exception_type_t exception,
 362         struct exception_action *excp,
 363         lck_mtx_t *mutex)
 364 {
 365         kern_return_t retval = KERN_SUCCESS;
 366
 367         if (excp == NULL || exception != EXC_CRASH)
 368                 return retval;
 369
 370         task_t task = current_task();
 371         lck_mtx_lock(mutex);
 372         ipc_port_t xport = excp[exception].port;
 373         if ( IP_VALID(xport)
 374                      && ip_active(xport)
 375                      && task->itk_space == xport->ip_receiver)
 376                 retval = KERN_FAILURE;
 377         lck_mtx_unlock(mutex);
 378         return retval;
 379 }
 380
 381
 382 /*
 383  *      Routine:        exception_triage_thread
 384  *      Purpose:
 385  *              The thread caught an exception.
 386  *              We make an up-call to the thread's exception server.
 387  *      Conditions:
 388  *              Nothing locked and no resources held.
 389  *              Called from an exception context, so
 390  *              thread_exception_return and thread_kdb_return
 391  *              are possible.
 392  *      Returns:
 393  *              KERN_SUCCESS if exception is handled by any of the handlers.
 394  */
 395 kern_return_t
 396 exception_triage_thread(
 397         exception_type_t        exception,
 398         mach_exception_data_t   code,
 399         mach_msg_type_number_t  codeCnt,
 400         thread_t                thread)
 401 {
 402         task_t                  task;
 403         host_priv_t             host_priv;
 404         lck_mtx_t               *mutex;
 405         kern_return_t   kr = KERN_FAILURE;
 406
 407         assert(exception != EXC_RPC_ALERT);
 408
 409         /*
 410          * If this behavior has been requested by the the kernel
 411          * (due to the boot environment), we should panic if we
 412          * enter this function.  This is intended as a debugging
 413          * aid; it should allow us to debug why we caught an
 414          * exception in environments where debugging is especially
 415          * difficult.
 416          */
 417         if (panic_on_exception_triage) {
 418                 panic("called exception_triage when it was forbidden by the boot environment");
 419         }
 420
 421         /*
 422          * Try to raise the exception at the activation level.
 423          */
 424         mutex = &thread->mutex;
 425         if (KERN_SUCCESS == check_exc_receiver_dependency(exception, thread->exc_actions, mutex))
 426         {
 427                 kr = exception_deliver(thread, exception, code, codeCnt, thread->exc_actions, mutex);
 428                 if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
 429                         goto out;
 430         }
 431
 432         /*
 433          * Maybe the task level will handle it.
 434          */
 435         task = thread->task;
 436         mutex = &task->itk_lock_data;
 437         if (KERN_SUCCESS == check_exc_receiver_dependency(exception, task->exc_actions, mutex))
 438         {
 439                 kr = exception_deliver(thread, exception, code, codeCnt, task->exc_actions, mutex);
 440                 if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
 441                         goto out;
 442         }
 443
 444         /*
 445          * How about at the host level?
 446          */
 447         host_priv = host_priv_self();
 448         mutex = &host_priv->lock;
 449
 450         if (KERN_SUCCESS == check_exc_receiver_dependency(exception, host_priv->exc_actions, mutex))
 451         {
 452                 kr = exception_deliver(thread, exception, code, codeCnt, host_priv->exc_actions, mutex);
 453                 if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
 454                         goto out;
 455         }
 456
 457 out:
 458         if ((exception != EXC_CRASH) && (exception != EXC_RESOURCE) &&
 459             (exception != EXC_GUARD) && (exception != EXC_CORPSE_NOTIFY))
 460                 thread_exception_return();
 461         return kr;
 462 }
 463
 464 /*
 465  *      Routine:        exception_triage
 466  *      Purpose:
 467  *              The current thread caught an exception.
 468  *              We make an up-call to the thread's exception server.
 469  *      Conditions:
 470  *              Nothing locked and no resources held.
 471  *              Called from an exception context, so
 472  *              thread_exception_return and thread_kdb_return
 473  *              are possible.
 474  *      Returns:
 475  *              KERN_SUCCESS if exception is handled by any of the handlers.
 476  */
 477 kern_return_t
 478 exception_triage(
 479         exception_type_t        exception,
 480         mach_exception_data_t   code,
 481         mach_msg_type_number_t  codeCnt)
 482 {
 483         thread_t thread = current_thread();
 484         return exception_triage_thread(exception, code, codeCnt, thread);
 485 }
 486
 487 kern_return_t
 488 bsd_exception(
 489         exception_type_t        exception,
 490         mach_exception_data_t   code,
 491         mach_msg_type_number_t  codeCnt)
 492 {
 493         task_t                  task;
 494         lck_mtx_t               *mutex;
 495         thread_t                self = current_thread();
 496         kern_return_t           kr;
 497
 498         /*
 499          * Maybe the task level will handle it.
 500          */
 501         task = current_task();
 502         mutex = &task->itk_lock_data;
 503
 504         kr = exception_deliver(self, exception, code, codeCnt, task->exc_actions, mutex);
 505
 506         if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
 507                 return(KERN_SUCCESS);
 508         return(KERN_FAILURE);
 509 }
 510
 511
 512 /*
 513  * Raise an exception on a task.
 514  * This should tell launchd to launch Crash Reporter for this task.
 515  */
 516 kern_return_t task_exception_notify(exception_type_t exception,
 517         mach_exception_data_type_t exccode, mach_exception_data_type_t excsubcode)
 518 {
 519         mach_exception_data_type_t      code[EXCEPTION_CODE_MAX];
 520         wait_interrupt_t                wsave;
 521         kern_return_t kr = KERN_SUCCESS;
 522
 523         code[0] = exccode;
 524         code[1] = excsubcode;
 525
 526         wsave = thread_interrupt_level(THREAD_UNINT);
 527         kr = exception_triage(exception, code, EXCEPTION_CODE_MAX);
 528         (void) thread_interrupt_level(wsave);
 529         return kr;
 530 }
 531
 532
 533 /*
 534  *      Handle interface for special performance monitoring
 535  *      This is a special case of the host exception handler
 536  */
 537 kern_return_t sys_perf_notify(thread_t thread, int pid)
 538 {
 539         host_priv_t             hostp;
 540         ipc_port_t              xport;
 541         wait_interrupt_t        wsave;
 542         kern_return_t           ret;
 543
 544         hostp = host_priv_self();       /* Get the host privileged ports */
 545         mach_exception_data_type_t      code[EXCEPTION_CODE_MAX];
 546         code[0] = 0xFF000001;           /* Set terminate code */
 547         code[1] = pid;          /* Pass out the pid */
 548
 549         struct task *task = thread->task;
 550         xport = hostp->exc_actions[EXC_RPC_ALERT].port;
 551
 552         /* Make sure we're not catching our own exception */
 553         if (!IP_VALID(xport) ||
 554                         !ip_active(xport) ||
 555                         task->itk_space == xport->data.receiver) {
 556
 557                 return(KERN_FAILURE);
 558         }
 559
 560         wsave = thread_interrupt_level(THREAD_UNINT);
 561         ret = exception_deliver(
 562                         thread,
 563                         EXC_RPC_ALERT,
 564                         code,
 565                         2,
 566                         hostp->exc_actions,
 567                         &hostp->lock);
 568         (void)thread_interrupt_level(wsave);
 569
 570         return(ret);
 571 }
 572