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336 lines
12 KiB
336 lines
12 KiB
/* |
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* Copyright 2006, The Android Open Source Project |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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#define LOG_TAG "crasher" |
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#include <assert.h> |
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#include <dirent.h> |
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#include <errno.h> |
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#include <fcntl.h> |
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#include <pthread.h> |
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#include <signal.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <sys/mman.h> |
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#include <sys/prctl.h> |
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#include <unistd.h> |
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// We test both kinds of logging. |
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#include <android-base/logging.h> |
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#include <log/log.h> |
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#include "seccomp_policy.h" |
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#if defined(STATIC_CRASHER) |
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#include "debuggerd/handler.h" |
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#endif |
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#if defined(__arm__) |
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// See https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt for details. |
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#define __kuser_helper_version (*(int32_t*) 0xffff0ffc) |
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typedef void * (__kuser_get_tls_t)(void); |
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#define __kuser_get_tls (*(__kuser_get_tls_t*) 0xffff0fe0) |
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typedef int (__kuser_cmpxchg_t)(int oldval, int newval, volatile int *ptr); |
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#define __kuser_cmpxchg (*(__kuser_cmpxchg_t*) 0xffff0fc0) |
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typedef void (__kuser_dmb_t)(void); |
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#define __kuser_dmb (*(__kuser_dmb_t*) 0xffff0fa0) |
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typedef int (__kuser_cmpxchg64_t)(const int64_t*, const int64_t*, volatile int64_t*); |
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#define __kuser_cmpxchg64 (*(__kuser_cmpxchg64_t*) 0xffff0f60) |
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#endif |
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#define noinline __attribute__((__noinline__)) |
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// Avoid name mangling so that stacks are more readable. |
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extern "C" { |
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void crash1(void); |
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void crashnostack(void); |
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int do_action(const char* arg); |
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noinline void maybe_abort() { |
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if (time(0) != 42) { |
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abort(); |
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} |
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} |
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char* smash_stack_dummy_buf; |
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noinline void smash_stack_dummy_function(volatile int* plen) { |
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smash_stack_dummy_buf[*plen] = 0; |
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} |
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// This must be marked with "__attribute__ ((noinline))", to ensure the |
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// compiler generates the proper stack guards around this function. |
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// Assign local array address to global variable to force stack guards. |
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// Use another noinline function to corrupt the stack. |
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noinline int smash_stack(volatile int* plen) { |
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printf("%s: deliberately corrupting stack...\n", getprogname()); |
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char buf[128]; |
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smash_stack_dummy_buf = buf; |
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// This should corrupt stack guards and make process abort. |
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smash_stack_dummy_function(plen); |
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return 0; |
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} |
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#pragma clang diagnostic push |
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#pragma clang diagnostic ignored "-Winfinite-recursion" |
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void* global = 0; // So GCC doesn't optimize the tail recursion out of overflow_stack. |
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noinline void overflow_stack(void* p) { |
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void* buf[1]; |
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buf[0] = p; |
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global = buf; |
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overflow_stack(&buf); |
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} |
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#pragma clang diagnostic pop |
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noinline void* thread_callback(void* raw_arg) { |
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const char* arg = reinterpret_cast<const char*>(raw_arg); |
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return reinterpret_cast<void*>(static_cast<uintptr_t>(do_action(arg))); |
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} |
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noinline int do_action_on_thread(const char* arg) { |
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pthread_t t; |
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pthread_create(&t, nullptr, thread_callback, const_cast<char*>(arg)); |
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void* result = nullptr; |
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pthread_join(t, &result); |
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return reinterpret_cast<uintptr_t>(result); |
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} |
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noinline int crash3(int a) { |
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*reinterpret_cast<int*>(0xdead) = a; |
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return a*4; |
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} |
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noinline int crash2(int a) { |
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a = crash3(a) + 2; |
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return a*3; |
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} |
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noinline int crash(int a) { |
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a = crash2(a) + 1; |
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return a*2; |
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} |
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noinline void abuse_heap() { |
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char buf[16]; |
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free(buf); // GCC is smart enough to warn about this, but we're doing it deliberately. |
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} |
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noinline void leak() { |
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while (true) { |
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void* mapping = |
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mmap(nullptr, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
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static_cast<volatile char*>(mapping)[0] = 'a'; |
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} |
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} |
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noinline void sigsegv_non_null() { |
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int* a = (int *)(&do_action); |
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*a = 42; |
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} |
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noinline void fprintf_null() { |
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fprintf(nullptr, "oops"); |
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} |
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noinline void readdir_null() { |
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readdir(nullptr); |
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} |
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noinline int strlen_null() { |
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char* sneaky_null = nullptr; |
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return strlen(sneaky_null); |
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} |
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static int usage() { |
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fprintf(stderr, "usage: %s KIND\n", getprogname()); |
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fprintf(stderr, "\n"); |
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fprintf(stderr, "where KIND is:\n"); |
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fprintf(stderr, " smash-stack overwrite a -fstack-protector guard\n"); |
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fprintf(stderr, " stack-overflow recurse until the stack overflows\n"); |
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fprintf(stderr, " nostack crash with a NULL stack pointer\n"); |
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fprintf(stderr, "\n"); |
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fprintf(stderr, " heap-usage cause a libc abort by abusing a heap function\n"); |
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fprintf(stderr, " leak leak memory until we get OOM-killed\n"); |
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fprintf(stderr, "\n"); |
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fprintf(stderr, " abort call abort()\n"); |
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fprintf(stderr, " assert call assert() without a function\n"); |
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fprintf(stderr, " assert2 call assert() with a function\n"); |
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fprintf(stderr, " exit call exit(1)\n"); |
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fprintf(stderr, "\n"); |
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fprintf(stderr, " fortify fail a _FORTIFY_SOURCE check\n"); |
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fprintf(stderr, " seccomp fail a seccomp check\n"); |
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#if defined(__arm__) |
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fprintf(stderr, " kuser_helper_version call kuser_helper_version\n"); |
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fprintf(stderr, " kuser_get_tls call kuser_get_tls\n"); |
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fprintf(stderr, " kuser_cmpxchg call kuser_cmpxchg\n"); |
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fprintf(stderr, " kuser_memory_barrier call kuser_memory_barrier\n"); |
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fprintf(stderr, " kuser_cmpxchg64 call kuser_cmpxchg64\n"); |
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#endif |
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fprintf(stderr, "\n"); |
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fprintf(stderr, " LOG_ALWAYS_FATAL call liblog LOG_ALWAYS_FATAL\n"); |
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fprintf(stderr, " LOG_ALWAYS_FATAL_IF call liblog LOG_ALWAYS_FATAL_IF\n"); |
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fprintf(stderr, " LOG-FATAL call libbase LOG(FATAL)\n"); |
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fprintf(stderr, "\n"); |
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fprintf(stderr, " SIGFPE cause a SIGFPE\n"); |
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fprintf(stderr, " SIGSEGV cause a SIGSEGV at address 0x0 (synonym: crash)\n"); |
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fprintf(stderr, " SIGSEGV-non-null cause a SIGSEGV at a non-zero address\n"); |
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fprintf(stderr, " SIGSEGV-unmapped mmap/munmap a region of memory and then attempt to access it\n"); |
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fprintf(stderr, " SIGTRAP cause a SIGTRAP\n"); |
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fprintf(stderr, "\n"); |
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fprintf(stderr, " fprintf-NULL pass a null pointer to fprintf\n"); |
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fprintf(stderr, " readdir-NULL pass a null pointer to readdir\n"); |
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fprintf(stderr, " strlen-NULL pass a null pointer to strlen\n"); |
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fprintf(stderr, " pthread_join-NULL pass a null pointer to pthread_join\n"); |
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fprintf(stderr, "\n"); |
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fprintf(stderr, " no_new_privs set PR_SET_NO_NEW_PRIVS and then abort\n"); |
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fprintf(stderr, "\n"); |
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fprintf(stderr, "prefix any of the above with 'thread-' to run on a new thread\n"); |
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fprintf(stderr, "prefix any of the above with 'exhaustfd-' to exhaust\n"); |
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fprintf(stderr, "all available file descriptors before crashing.\n"); |
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fprintf(stderr, "prefix any of the above with 'wait-' to wait until input is received on stdin\n"); |
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return EXIT_FAILURE; |
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} |
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noinline int do_action(const char* arg) { |
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// Prefixes. |
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if (!strncmp(arg, "wait-", strlen("wait-"))) { |
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char buf[1]; |
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TEMP_FAILURE_RETRY(read(STDIN_FILENO, buf, sizeof(buf))); |
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return do_action(arg + strlen("wait-")); |
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} else if (!strncmp(arg, "exhaustfd-", strlen("exhaustfd-"))) { |
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errno = 0; |
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while (errno != EMFILE) { |
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open("/dev/null", O_RDONLY); |
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} |
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return do_action(arg + strlen("exhaustfd-")); |
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} else if (!strncmp(arg, "thread-", strlen("thread-"))) { |
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return do_action_on_thread(arg + strlen("thread-")); |
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} |
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// Actions. |
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if (!strcasecmp(arg, "SIGSEGV-non-null")) { |
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sigsegv_non_null(); |
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} else if (!strcasecmp(arg, "smash-stack")) { |
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volatile int len = 128; |
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return smash_stack(&len); |
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} else if (!strcasecmp(arg, "stack-overflow")) { |
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overflow_stack(nullptr); |
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} else if (!strcasecmp(arg, "nostack")) { |
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crashnostack(); |
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} else if (!strcasecmp(arg, "exit")) { |
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exit(1); |
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} else if (!strcasecmp(arg, "crash") || !strcmp(arg, "SIGSEGV")) { |
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return crash(42); |
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} else if (!strcasecmp(arg, "abort")) { |
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maybe_abort(); |
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} else if (!strcasecmp(arg, "assert")) { |
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__assert("some_file.c", 123, "false"); |
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} else if (!strcasecmp(arg, "assert2")) { |
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__assert2("some_file.c", 123, "some_function", "false"); |
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} else if (!strcasecmp(arg, "fortify")) { |
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char buf[10]; |
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__read_chk(-1, buf, 32, 10); |
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while (true) pause(); |
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} else if (!strcasecmp(arg, "LOG(FATAL)")) { |
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LOG(FATAL) << "hello " << 123; |
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} else if (!strcasecmp(arg, "LOG_ALWAYS_FATAL")) { |
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LOG_ALWAYS_FATAL("hello %s", "world"); |
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} else if (!strcasecmp(arg, "LOG_ALWAYS_FATAL_IF")) { |
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LOG_ALWAYS_FATAL_IF(true, "hello %s", "world"); |
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} else if (!strcasecmp(arg, "SIGFPE")) { |
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raise(SIGFPE); |
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return EXIT_SUCCESS; |
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} else if (!strcasecmp(arg, "SIGTRAP")) { |
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raise(SIGTRAP); |
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return EXIT_SUCCESS; |
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} else if (!strcasecmp(arg, "fprintf-NULL")) { |
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fprintf_null(); |
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} else if (!strcasecmp(arg, "readdir-NULL")) { |
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readdir_null(); |
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} else if (!strcasecmp(arg, "strlen-NULL")) { |
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return strlen_null(); |
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} else if (!strcasecmp(arg, "pthread_join-NULL")) { |
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return pthread_join(0, nullptr); |
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} else if (!strcasecmp(arg, "heap-usage")) { |
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abuse_heap(); |
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} else if (!strcasecmp(arg, "leak")) { |
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leak(); |
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} else if (!strcasecmp(arg, "SIGSEGV-unmapped")) { |
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char* map = reinterpret_cast<char*>(mmap(nullptr, sizeof(int), PROT_READ | PROT_WRITE, |
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MAP_SHARED | MAP_ANONYMOUS, -1, 0)); |
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munmap(map, sizeof(int)); |
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map[0] = '8'; |
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} else if (!strcasecmp(arg, "seccomp")) { |
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set_seccomp_filter(); |
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syscall(99999); |
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#if defined(__arm__) |
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} else if (!strcasecmp(arg, "kuser_helper_version")) { |
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return __kuser_helper_version; |
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} else if (!strcasecmp(arg, "kuser_get_tls")) { |
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return !__kuser_get_tls(); |
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} else if (!strcasecmp(arg, "kuser_cmpxchg")) { |
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return __kuser_cmpxchg(0, 0, 0); |
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} else if (!strcasecmp(arg, "kuser_memory_barrier")) { |
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__kuser_dmb(); |
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} else if (!strcasecmp(arg, "kuser_cmpxchg64")) { |
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return __kuser_cmpxchg64(0, 0, 0); |
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#endif |
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} else if (!strcasecmp(arg, "no_new_privs")) { |
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if (prctl(PR_SET_NO_NEW_PRIVS, 1) != 0) { |
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fprintf(stderr, "prctl(PR_SET_NO_NEW_PRIVS, 1) failed: %s\n", strerror(errno)); |
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return EXIT_SUCCESS; |
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} |
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abort(); |
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} else { |
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return usage(); |
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} |
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fprintf(stderr, "%s: exiting normally!\n", getprogname()); |
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return EXIT_SUCCESS; |
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} |
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int main(int argc, char** argv) { |
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#if defined(STATIC_CRASHER) |
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debuggerd_callbacks_t callbacks = { |
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.get_abort_message = []() { |
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static struct { |
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size_t size; |
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char msg[32]; |
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} msg; |
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msg.size = strlen("dummy abort message"); |
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memcpy(msg.msg, "dummy abort message", strlen("dummy abort message")); |
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return reinterpret_cast<abort_msg_t*>(&msg); |
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}, |
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.post_dump = nullptr |
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}; |
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debuggerd_init(&callbacks); |
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#endif |
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if (argc == 1) crash1(); |
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else if (argc == 2) return do_action(argv[1]); |
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return usage(); |
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} |
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};
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