bsd/uxkern/ux_exception.c

   1 /*
   2  * Copyright (c) 2000-2016 Apple 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  * Mach Operating System
  30  * Copyright (c) 1987 Carnegie-Mellon University
  31  * All rights reserved.  The CMU software License Agreement specifies
  32  * the terms and conditions for use and redistribution.
  33  */
  34
  35 /*
  36  *********************************************************************
  37  * HISTORY
  38  **********************************************************************
  39  */
  40
  41 #include <sys/param.h>
  42
  43 #include <mach/boolean.h>
  44 #include <mach/exception.h>
  45 #include <mach/kern_return.h>
  46 #include <mach/message.h>
  47 #include <mach/port.h>
  48 #include <mach/mach_port.h>
  49 #include <mach/mig_errors.h>
  50 #include <mach/exc_server.h>
  51 #include <mach/mach_exc_server.h>
  52 #include <kern/task.h>
  53 #include <kern/thread.h>
  54 #include <kern/sched_prim.h>
  55 #include <kern/kalloc.h>
  56
  57 #include <sys/proc.h>
  58 #include <sys/user.h>
  59 #include <sys/systm.h>
  60 #include <sys/ux_exception.h>
  61 #include <sys/vmparam.h>        /* MAXSSIZ */
  62
  63 #include <vm/vm_protos.h>       /* get_task_ipcspace() */
  64 /*
  65  * XXX Things that should be retrieved from Mach headers, but aren't
  66  */
  67 struct ipc_object;
  68 extern kern_return_t ipc_object_copyin(ipc_space_t space, mach_port_name_t name,
  69                 mach_msg_type_name_t msgt_name, struct ipc_object **objectp);
  70 extern mach_msg_return_t mach_msg_receive(mach_msg_header_t *msg,
  71                 mach_msg_option_t option, mach_msg_size_t rcv_size,
  72                 mach_port_name_t rcv_name, mach_msg_timeout_t rcv_timeout,
  73                 void (*continuation)(mach_msg_return_t),
  74                 mach_msg_size_t slist_size);
  75 extern mach_msg_return_t mach_msg_send(mach_msg_header_t *msg,
  76                 mach_msg_option_t option, mach_msg_size_t send_size,
  77                 mach_msg_timeout_t send_timeout, mach_port_name_t notify);
  78 extern thread_t convert_port_to_thread(ipc_port_t port);
  79 extern void ipc_port_release_send(ipc_port_t port);
  80
  81
  82
  83
  84 /*
  85  *      Unix exception handler.
  86  */
  87
  88 static void     ux_exception(int exception, mach_exception_code_t code,
  89                                 mach_exception_subcode_t subcode,
  90                                 int *ux_signal, mach_exception_code_t *ux_code);
  91
  92 #if defined(__x86_64__) || defined(__arm64__)
  93 mach_port_t                     ux_exception_port;
  94 #else
  95 mach_port_name_t                ux_exception_port;
  96 #endif /* __x86_64__ */
  97
  98 static task_t                   ux_handler_self;
  99
 100 __attribute__((noreturn))
 101 static void
 102 ux_handler(void)
 103 {
 104     task_t              self = current_task();
 105     mach_port_name_t    exc_port_name;
 106     mach_port_name_t    exc_set_name;
 107
 108     /* self->kernel_vm_space = TRUE; */
 109     ux_handler_self = self;
 110
 111
 112     /*
 113      *  Allocate a port set that we will receive on.
 114      */
 115     if (mach_port_allocate(get_task_ipcspace(ux_handler_self), MACH_PORT_RIGHT_PORT_SET,  &exc_set_name) != MACH_MSG_SUCCESS)
 116             panic("ux_handler: port_set_allocate failed");
 117
 118     /*
 119      *  Allocate an exception port and use object_copyin to
 120      *  translate it to the global name.  Put it into the set.
 121      */
 122     if (mach_port_allocate(get_task_ipcspace(ux_handler_self), MACH_PORT_RIGHT_RECEIVE, &exc_port_name) != MACH_MSG_SUCCESS)
 123         panic("ux_handler: port_allocate failed");
 124     if (mach_port_move_member(get_task_ipcspace(ux_handler_self),
 125                         exc_port_name,  exc_set_name) != MACH_MSG_SUCCESS)
 126         panic("ux_handler: port_set_add failed");
 127
 128     if (ipc_object_copyin(get_task_ipcspace(self), exc_port_name,
 129                         MACH_MSG_TYPE_MAKE_SEND,
 130                         (void *) &ux_exception_port) != MACH_MSG_SUCCESS)
 131                 panic("ux_handler: object_copyin(ux_exception_port) failed");
 132
 133     proc_list_lock();
 134     thread_wakeup(&ux_exception_port);
 135     proc_list_unlock();
 136
 137     /* Message handling loop. */
 138
 139     for (;;) {
 140         struct rep_msg {
 141                 mach_msg_header_t Head;
 142                 NDR_record_t NDR;
 143                 kern_return_t RetCode;
 144         } rep_msg;
 145         struct exc_msg {
 146                 mach_msg_header_t Head;
 147                 /* start of the kernel processed data */
 148                 mach_msg_body_t msgh_body;
 149                 mach_msg_port_descriptor_t thread;
 150                 mach_msg_port_descriptor_t task;
 151                 /* end of the kernel processed data */
 152                 NDR_record_t NDR;
 153                 exception_type_t exception;
 154                 mach_msg_type_number_t codeCnt;
 155                 mach_exception_data_t code;
 156                 /* some times RCV_TO_LARGE probs */
 157                 char pad[512];
 158         } exc_msg;
 159         mach_port_name_t        reply_port;
 160         kern_return_t    result;
 161
 162         exc_msg.Head.msgh_local_port = CAST_MACH_NAME_TO_PORT(exc_set_name);
 163         exc_msg.Head.msgh_size = sizeof (exc_msg);
 164 #if 0
 165         result = mach_msg_receive(&exc_msg.Head);
 166 #else
 167         result = mach_msg_receive(&exc_msg.Head, MACH_RCV_MSG,
 168                              sizeof (exc_msg), exc_set_name,
 169                              MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL,
 170                              0);
 171 #endif
 172         if (result == MACH_MSG_SUCCESS) {
 173             reply_port = CAST_MACH_PORT_TO_NAME(exc_msg.Head.msgh_remote_port);
 174
 175             if (mach_exc_server(&exc_msg.Head, &rep_msg.Head)) {
 176                 result = mach_msg_send(&rep_msg.Head, MACH_SEND_MSG,
 177                         sizeof (rep_msg),MACH_MSG_TIMEOUT_NONE,MACH_PORT_NULL);
 178                 if (reply_port != 0 && result != MACH_MSG_SUCCESS)
 179                         mach_port_deallocate(get_task_ipcspace(ux_handler_self), reply_port);
 180             }
 181
 182         }
 183         else if (result == MACH_RCV_TOO_LARGE)
 184                 /* ignore oversized messages */;
 185         else
 186                 panic("exception_handler");
 187     }
 188 }
 189
 190 void
 191 ux_handler_init(void)
 192 {
 193         thread_t        thread = THREAD_NULL;
 194
 195         ux_exception_port = MACH_PORT_NULL;
 196         (void) kernel_thread_start((thread_continue_t)ux_handler, NULL, &thread);
 197         thread_deallocate(thread);
 198         proc_list_lock();
 199         if (ux_exception_port == MACH_PORT_NULL)  {
 200                 (void)msleep(&ux_exception_port, proc_list_mlock, 0, "ux_handler_wait", 0);
 201         }
 202         proc_list_unlock();
 203 }
 204
 205 kern_return_t
 206 catch_exception_raise(
 207         __unused mach_port_t exception_port,
 208         mach_port_t thread,
 209         mach_port_t task,
 210         exception_type_t exception,
 211         exception_data_t code,
 212         __unused mach_msg_type_number_t codeCnt
 213 )
 214 {
 215         mach_exception_data_type_t big_code[EXCEPTION_CODE_MAX];
 216         big_code[0] = code[0];
 217         big_code[1] = code[1];
 218
 219         return catch_mach_exception_raise(exception_port,
 220                         thread,
 221                         task,
 222                         exception,
 223                         big_code,
 224                         codeCnt);
 225
 226 }
 227
 228 kern_return_t
 229 catch_mach_exception_raise(
 230         __unused mach_port_t exception_port,
 231         mach_port_t thread,
 232         mach_port_t task,
 233         exception_type_t exception,
 234         mach_exception_data_t code,
 235         __unused mach_msg_type_number_t codeCnt
 236 )
 237 {
 238         task_t                  self = current_task();
 239         thread_t                th_act;
 240         ipc_port_t              thread_port;
 241         struct proc             *p;
 242         kern_return_t           result = MACH_MSG_SUCCESS;
 243         int                     ux_signal = 0;
 244         mach_exception_code_t   ucode = 0;
 245         struct uthread          *ut;
 246         mach_port_name_t thread_name = CAST_MACH_PORT_TO_NAME(thread);
 247         mach_port_name_t task_name = CAST_MACH_PORT_TO_NAME(task);
 248
 249         /*
 250          *      Convert local thread name to global port.
 251          */
 252    if (MACH_PORT_VALID(thread_name) &&
 253        (ipc_object_copyin(get_task_ipcspace(self), thread_name,
 254                        MACH_MSG_TYPE_PORT_SEND,
 255                        (void *) &thread_port) == MACH_MSG_SUCCESS)) {
 256         if (IPC_PORT_VALID(thread_port)) {
 257            th_act = convert_port_to_thread(thread_port);
 258            ipc_port_release_send(thread_port);
 259         } else {
 260            th_act = THREAD_NULL;
 261         }
 262
 263         /*
 264          *      Catch bogus ports
 265          */
 266         if (th_act != THREAD_NULL) {
 267
 268             /*
 269              *  Convert exception to unix signal and code.
 270              */
 271             ux_exception(exception, code[0], code[1], &ux_signal, &ucode);
 272
 273             ut = get_bsdthread_info(th_act);
 274             p = proc_findthread(th_act);
 275
 276             /* Can't deliver a signal without a bsd process reference */
 277             if (p == NULL) {
 278                     ux_signal = 0;
 279                     result = KERN_FAILURE;
 280             }
 281
 282             /*
 283              * Stack overflow should result in a SIGSEGV signal
 284              * on the alternate stack.
 285              * but we have one or more guard pages after the
 286              * stack top, so we would get a KERN_PROTECTION_FAILURE
 287              * exception instead of KERN_INVALID_ADDRESS, resulting in
 288              * a SIGBUS signal.
 289              * Detect that situation and select the correct signal.
 290              */
 291             if (code[0] == KERN_PROTECTION_FAILURE &&
 292                 ux_signal == SIGBUS) {
 293                     user_addr_t         sp, stack_min, stack_max;
 294                     int                 mask;
 295                     struct sigacts      *ps;
 296
 297                     sp = code[1];
 298
 299                     stack_max = p->user_stack;
 300                     stack_min = p->user_stack - MAXSSIZ;
 301                     if (sp >= stack_min &&
 302                         sp < stack_max) {
 303                             /*
 304                              * This is indeed a stack overflow.  Deliver a
 305                              * SIGSEGV signal.
 306                              */
 307                             ux_signal = SIGSEGV;
 308
 309                             /*
 310                              * If the thread/process is not ready to handle
 311                              * SIGSEGV on an alternate stack, force-deliver
 312                              * SIGSEGV with a SIG_DFL handler.
 313                              */
 314                             mask = sigmask(ux_signal);
 315                             ps = p->p_sigacts;
 316                             if ((p->p_sigignore & mask) ||
 317                                 (ut->uu_sigwait & mask) ||
 318                                 (ut->uu_sigmask & mask) ||
 319                                 (ps->ps_sigact[SIGSEGV] == SIG_IGN) ||
 320                                 (! (ps->ps_sigonstack & mask))) {
 321                                     p->p_sigignore &= ~mask;
 322                                     p->p_sigcatch &= ~mask;
 323                                     ps->ps_sigact[SIGSEGV] = SIG_DFL;
 324                                     ut->uu_sigwait &= ~mask;
 325                                     ut->uu_sigmask &= ~mask;
 326                             }
 327                     }
 328             }
 329             /*
 330              *  Send signal.
 331              */
 332             if (ux_signal != 0) {
 333                         ut->uu_exception = exception;
 334                         //ut->uu_code = code[0]; // filled in by threadsignal
 335                         ut->uu_subcode = code[1];
 336                         threadsignal(th_act, ux_signal, code[0], TRUE);
 337             }
 338             if (p != NULL)
 339                     proc_rele(p);
 340             thread_deallocate(th_act);
 341         }
 342         else
 343             result = KERN_INVALID_ARGUMENT;
 344     }
 345     else
 346         result = KERN_INVALID_ARGUMENT;
 347
 348     /*
 349      *  Delete our send rights to the task port.
 350      */
 351     (void)mach_port_deallocate(get_task_ipcspace(ux_handler_self), task_name);
 352
 353     return (result);
 354 }
 355
 356 kern_return_t
 357 catch_exception_raise_state(
 358         __unused mach_port_t exception_port,
 359         __unused exception_type_t exception,
 360         __unused const exception_data_t code,
 361         __unused mach_msg_type_number_t codeCnt,
 362         __unused int *flavor,
 363         __unused const thread_state_t old_state,
 364         __unused mach_msg_type_number_t old_stateCnt,
 365         __unused thread_state_t new_state,
 366         __unused mach_msg_type_number_t *new_stateCnt)
 367 {
 368         return(KERN_INVALID_ARGUMENT);
 369 }
 370
 371 kern_return_t
 372 catch_mach_exception_raise_state(
 373         __unused mach_port_t exception_port,
 374         __unused exception_type_t exception,
 375         __unused const mach_exception_data_t code,
 376         __unused mach_msg_type_number_t codeCnt,
 377         __unused int *flavor,
 378         __unused const thread_state_t old_state,
 379         __unused mach_msg_type_number_t old_stateCnt,
 380         __unused thread_state_t new_state,
 381         __unused mach_msg_type_number_t *new_stateCnt)
 382 {
 383         return(KERN_INVALID_ARGUMENT);
 384 }
 385
 386 kern_return_t
 387 catch_exception_raise_state_identity(
 388         __unused mach_port_t exception_port,
 389         __unused mach_port_t thread,
 390         __unused mach_port_t task,
 391         __unused exception_type_t exception,
 392         __unused exception_data_t code,
 393         __unused mach_msg_type_number_t codeCnt,
 394         __unused int *flavor,
 395         __unused thread_state_t old_state,
 396         __unused mach_msg_type_number_t old_stateCnt,
 397         __unused thread_state_t new_state,
 398         __unused mach_msg_type_number_t *new_stateCnt)
 399 {
 400         return(KERN_INVALID_ARGUMENT);
 401 }
 402
 403 kern_return_t
 404 catch_mach_exception_raise_state_identity(
 405         __unused mach_port_t exception_port,
 406         __unused mach_port_t thread,
 407         __unused mach_port_t task,
 408         __unused exception_type_t exception,
 409         __unused mach_exception_data_t code,
 410         __unused mach_msg_type_number_t codeCnt,
 411         __unused int *flavor,
 412         __unused thread_state_t old_state,
 413         __unused mach_msg_type_number_t old_stateCnt,
 414         __unused thread_state_t new_state,
 415         __unused mach_msg_type_number_t *new_stateCnt)
 416 {
 417         return(KERN_INVALID_ARGUMENT);
 418 }
 419
 420
 421 /*
 422  *      ux_exception translates a mach exception, code and subcode to
 423  *      a signal and u.u_code.  Calls machine_exception (machine dependent)
 424  *      to attempt translation first.
 425  */
 426
 427 static
 428 void ux_exception(
 429                 int                     exception,
 430                 mach_exception_code_t   code,
 431                 mach_exception_subcode_t subcode,
 432                 int                     *ux_signal,
 433                 mach_exception_code_t   *ux_code)
 434 {
 435     /*
 436      *  Try machine-dependent translation first.
 437      */
 438     if (machine_exception(exception, code, subcode, ux_signal, ux_code))
 439         return;
 440
 441     switch(exception) {
 442
 443         case EXC_BAD_ACCESS:
 444                 if (code == KERN_INVALID_ADDRESS)
 445                         *ux_signal = SIGSEGV;
 446                 else
 447                         *ux_signal = SIGBUS;
 448                 break;
 449
 450         case EXC_BAD_INSTRUCTION:
 451             *ux_signal = SIGILL;
 452             break;
 453
 454         case EXC_ARITHMETIC:
 455             *ux_signal = SIGFPE;
 456             break;
 457
 458         case EXC_EMULATION:
 459             *ux_signal = SIGEMT;
 460             break;
 461
 462         case EXC_SOFTWARE:
 463             switch (code) {
 464
 465             case EXC_UNIX_BAD_SYSCALL:
 466                 *ux_signal = SIGSYS;
 467                 break;
 468             case EXC_UNIX_BAD_PIPE:
 469                 *ux_signal = SIGPIPE;
 470                 break;
 471             case EXC_UNIX_ABORT:
 472                 *ux_signal = SIGABRT;
 473                 break;
 474             case EXC_SOFT_SIGNAL:
 475                 *ux_signal = SIGKILL;
 476                 break;
 477             }
 478             break;
 479
 480         case EXC_BREAKPOINT:
 481             *ux_signal = SIGTRAP;
 482             break;
 483     }
 484 }