X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/39236c6e673c41db228275375ab7fdb0f837b292..3903760236c30e3b5ace7a4eefac3a269d68957c:/osfmk/kern/exception.c diff --git a/osfmk/kern/exception.c b/osfmk/kern/exception.c index d8128145d..a93f38ca5 100644 --- a/osfmk/kern/exception.c +++ b/osfmk/kern/exception.c @@ -83,9 +83,12 @@ #include #include #include +#include #include #include +extern int panic_on_exception_triage; + unsigned long c_thr_exc_raise = 0; unsigned long c_thr_exc_raise_state = 0; unsigned long c_thr_exc_raise_state_id = 0; @@ -102,6 +105,12 @@ kern_return_t exception_deliver( struct exception_action *excp, lck_mtx_t *mutex); +static kern_return_t +check_exc_receiver_dependency( + exception_type_t exception, + struct exception_action *excp, + lck_mtx_t *mutex); + #ifdef MACH_BSD kern_return_t bsd_exception( exception_type_t exception, @@ -136,12 +145,15 @@ exception_deliver( int behavior; int flavor; kern_return_t kr; + int use_fast_retrieve = TRUE; + task_t task; + ipc_port_t thread_port = NULL, task_port = NULL; /* * Save work if we are terminating. * Just go back to our AST handler. */ - if (!thread->active) + if (!thread->active && !thread->inspection) return KERN_SUCCESS; /* @@ -192,6 +204,32 @@ exception_deliver( small_code[1] = CAST_DOWN_EXPLICIT(exception_data_type_t, code[1]); } + task = thread->task; + +#if CONFIG_MACF + /* Now is a reasonably good time to check if the exception action is + * permitted for this process, because after this point we will send + * the message out almost certainly. + * As with other failures, exception_triage_thread will go on + * to the next level. + */ + if (mac_exc_action_check_exception_send(task, excp) != 0) { + return KERN_FAILURE; + } +#endif + + if ((thread != current_thread() || exception == EXC_CORPSE_NOTIFY) + && behavior != EXCEPTION_STATE) { + use_fast_retrieve = FALSE; + + task_reference(task); + task_port = convert_task_to_port(task); + /* task ref consumed */ + thread_reference(thread); + thread_port = convert_thread_to_port(thread); + /* thread ref consumed */ + + } switch (behavior) { case EXCEPTION_STATE: { @@ -220,7 +258,7 @@ exception_deliver( state, state_cnt, state, &state_cnt); } - if (kr == MACH_MSG_SUCCESS) + if (kr == MACH_MSG_SUCCESS && exception != EXC_CORPSE_NOTIFY) kr = thread_setstatus(thread, flavor, (thread_state_t)state, state_cnt); @@ -233,15 +271,19 @@ exception_deliver( c_thr_exc_raise++; if (code64) { kr = mach_exception_raise(exc_port, - retrieve_thread_self_fast(thread), - retrieve_task_self_fast(thread->task), + use_fast_retrieve ? retrieve_thread_self_fast(thread) : + thread_port, + use_fast_retrieve ? retrieve_task_self_fast(thread->task) : + task_port, exception, code, codeCnt); } else { kr = exception_raise(exc_port, - retrieve_thread_self_fast(thread), - retrieve_task_self_fast(thread->task), + use_fast_retrieve ? retrieve_thread_self_fast(thread) : + thread_port, + use_fast_retrieve ? retrieve_task_self_fast(thread->task) : + task_port, exception, small_code, codeCnt); @@ -262,8 +304,10 @@ exception_deliver( if (code64) { kr = mach_exception_raise_state_identity( exc_port, - retrieve_thread_self_fast(thread), - retrieve_task_self_fast(thread->task), + use_fast_retrieve ? retrieve_thread_self_fast(thread) : + thread_port, + use_fast_retrieve ? retrieve_task_self_fast(thread->task) : + task_port, exception, code, codeCnt, @@ -272,8 +316,10 @@ exception_deliver( state, &state_cnt); } else { kr = exception_raise_state_identity(exc_port, - retrieve_thread_self_fast(thread), - retrieve_task_self_fast(thread->task), + use_fast_retrieve ? retrieve_thread_self_fast(thread) : + thread_port, + use_fast_retrieve ? retrieve_task_self_fast(thread->task) : + task_port, exception, small_code, codeCnt, @@ -281,7 +327,7 @@ exception_deliver( state, state_cnt, state, &state_cnt); } - if (kr == MACH_MSG_SUCCESS) + if (kr == MACH_MSG_SUCCESS && exception != EXC_CORPSE_NOTIFY) kr = thread_setstatus(thread, flavor, (thread_state_t)state, state_cnt); @@ -297,9 +343,46 @@ exception_deliver( } /* - * Routine: exception + * Routine: check_exc_receiver_dependency + * Purpose: + * Verify that the port destined for receiving this exception is not + * on the current task. This would cause hang in kernel for + * EXC_CRASH primarily. Note: If port is transferred + * between check and delivery then deadlock may happen. + * + * Conditions: + * Nothing locked and no resources held. + * Called from an exception context. + * Returns: + * KERN_SUCCESS if its ok to send exception message. + */ +kern_return_t +check_exc_receiver_dependency( + exception_type_t exception, + struct exception_action *excp, + lck_mtx_t *mutex) +{ + kern_return_t retval = KERN_SUCCESS; + + if (excp == NULL || exception != EXC_CRASH) + return retval; + + task_t task = current_task(); + lck_mtx_lock(mutex); + ipc_port_t xport = excp[exception].port; + if ( IP_VALID(xport) + && ip_active(xport) + && task->itk_space == xport->ip_receiver) + retval = KERN_FAILURE; + lck_mtx_unlock(mutex); + return retval; +} + + +/* + * Routine: exception_triage_thread * Purpose: - * The current thread caught an exception. + * The thread caught an exception. * We make an up-call to the thread's exception server. * Conditions: * Nothing locked and no resources held. @@ -307,61 +390,98 @@ exception_deliver( * thread_exception_return and thread_kdb_return * are possible. * Returns: - * Doesn't return. + * KERN_SUCCESS if exception is handled by any of the handlers. */ -void -exception_triage( +kern_return_t +exception_triage_thread( exception_type_t exception, mach_exception_data_t code, - mach_msg_type_number_t codeCnt) + mach_msg_type_number_t codeCnt, + thread_t thread) { - thread_t thread; task_t task; host_priv_t host_priv; lck_mtx_t *mutex; - kern_return_t kr; + kern_return_t kr = KERN_FAILURE; assert(exception != EXC_RPC_ALERT); - thread = current_thread(); + /* + * If this behavior has been requested by the the kernel + * (due to the boot environment), we should panic if we + * enter this function. This is intended as a debugging + * aid; it should allow us to debug why we caught an + * exception in environments where debugging is especially + * difficult. + */ + if (panic_on_exception_triage) { + panic("called exception_triage when it was forbidden by the boot environment"); + } /* * Try to raise the exception at the activation level. */ mutex = &thread->mutex; - kr = exception_deliver(thread, exception, code, codeCnt, thread->exc_actions, mutex); - if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) - goto out; + if (KERN_SUCCESS == check_exc_receiver_dependency(exception, thread->exc_actions, mutex)) + { + kr = exception_deliver(thread, exception, code, codeCnt, thread->exc_actions, mutex); + if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) + goto out; + } /* * Maybe the task level will handle it. */ - task = current_task(); - mutex = &task->lock; - kr = exception_deliver(thread, exception, code, codeCnt, task->exc_actions, mutex); - if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) - goto out; + task = thread->task; + mutex = &task->itk_lock_data; + if (KERN_SUCCESS == check_exc_receiver_dependency(exception, task->exc_actions, mutex)) + { + kr = exception_deliver(thread, exception, code, codeCnt, task->exc_actions, mutex); + if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) + goto out; + } /* * How about at the host level? */ host_priv = host_priv_self(); mutex = &host_priv->lock; - kr = exception_deliver(thread, exception, code, codeCnt, host_priv->exc_actions, mutex); - if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) - goto out; - - /* - * Nobody handled it, terminate the task. - */ - - (void) task_terminate(task); + + if (KERN_SUCCESS == check_exc_receiver_dependency(exception, host_priv->exc_actions, mutex)) + { + kr = exception_deliver(thread, exception, code, codeCnt, host_priv->exc_actions, mutex); + if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) + goto out; + } out: if ((exception != EXC_CRASH) && (exception != EXC_RESOURCE) && - (exception != EXC_GUARD)) + (exception != EXC_GUARD) && (exception != EXC_CORPSE_NOTIFY)) thread_exception_return(); - return; + return kr; +} + +/* + * Routine: exception_triage + * Purpose: + * The current thread caught an exception. + * We make an up-call to the thread's exception server. + * Conditions: + * Nothing locked and no resources held. + * Called from an exception context, so + * thread_exception_return and thread_kdb_return + * are possible. + * Returns: + * KERN_SUCCESS if exception is handled by any of the handlers. + */ +kern_return_t +exception_triage( + exception_type_t exception, + mach_exception_data_t code, + mach_msg_type_number_t codeCnt) +{ + thread_t thread = current_thread(); + return exception_triage_thread(exception, code, codeCnt, thread); } kern_return_t @@ -379,7 +499,7 @@ bsd_exception( * Maybe the task level will handle it. */ task = current_task(); - mutex = &task->lock; + mutex = &task->itk_lock_data; kr = exception_deliver(self, exception, code, codeCnt, task->exc_actions, mutex); @@ -398,14 +518,15 @@ kern_return_t task_exception_notify(exception_type_t exception, { mach_exception_data_type_t code[EXCEPTION_CODE_MAX]; wait_interrupt_t wsave; + kern_return_t kr = KERN_SUCCESS; code[0] = exccode; code[1] = excsubcode; wsave = thread_interrupt_level(THREAD_UNINT); - exception_triage(exception, code, EXCEPTION_CODE_MAX); + kr = exception_triage(exception, code, EXCEPTION_CODE_MAX); (void) thread_interrupt_level(wsave); - return (KERN_SUCCESS); + return kr; }