| /* |
| * Copyright 2006, The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "crasher" |
| |
| #include <assert.h> |
| #include <dirent.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <pthread.h> |
| #include <signal.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/mman.h> |
| #include <sys/prctl.h> |
| #include <unistd.h> |
| |
| // We test both kinds of logging. |
| #include <android-base/logging.h> |
| #include <log/log.h> |
| |
| #include "seccomp_policy.h" |
| |
| #if defined(STATIC_CRASHER) |
| #include "debuggerd/handler.h" |
| #endif |
| |
| extern "C" void android_set_abort_message(const char* msg); |
| |
| #if defined(__arm__) |
| // See https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt for details. |
| #define __kuser_helper_version (*(int32_t*) 0xffff0ffc) |
| typedef void * (__kuser_get_tls_t)(void); |
| #define __kuser_get_tls (*(__kuser_get_tls_t*) 0xffff0fe0) |
| typedef int (__kuser_cmpxchg_t)(int oldval, int newval, volatile int *ptr); |
| #define __kuser_cmpxchg (*(__kuser_cmpxchg_t*) 0xffff0fc0) |
| typedef void (__kuser_dmb_t)(void); |
| #define __kuser_dmb (*(__kuser_dmb_t*) 0xffff0fa0) |
| typedef int (__kuser_cmpxchg64_t)(const int64_t*, const int64_t*, volatile int64_t*); |
| #define __kuser_cmpxchg64 (*(__kuser_cmpxchg64_t*) 0xffff0f60) |
| #endif |
| |
| #define noinline __attribute__((__noinline__)) |
| |
| // Avoid name mangling so that stacks are more readable. |
| extern "C" { |
| |
| void crash1(void); |
| void crashnostack(void); |
| |
| int do_action(const char* arg); |
| |
| noinline void maybe_abort() { |
| if (time(0) != 42) { |
| abort(); |
| } |
| } |
| |
| char* smash_stack_dummy_buf; |
| noinline void smash_stack_dummy_function(volatile int* plen) { |
| smash_stack_dummy_buf[*plen] = 0; |
| } |
| |
| // This must be marked with "__attribute__ ((noinline))", to ensure the |
| // compiler generates the proper stack guards around this function. |
| // Assign local array address to global variable to force stack guards. |
| // Use another noinline function to corrupt the stack. |
| noinline int smash_stack(volatile int* plen) { |
| printf("%s: deliberately corrupting stack...\n", getprogname()); |
| |
| char buf[128]; |
| smash_stack_dummy_buf = buf; |
| // This should corrupt stack guards and make process abort. |
| smash_stack_dummy_function(plen); |
| return 0; |
| } |
| |
| #pragma clang diagnostic push |
| #pragma clang diagnostic ignored "-Winfinite-recursion" |
| |
| void* global = 0; // So GCC doesn't optimize the tail recursion out of overflow_stack. |
| |
| noinline void overflow_stack(void* p) { |
| void* buf[1]; |
| buf[0] = p; |
| global = buf; |
| overflow_stack(&buf); |
| } |
| |
| #pragma clang diagnostic pop |
| |
| noinline void* thread_callback(void* raw_arg) { |
| const char* arg = reinterpret_cast<const char*>(raw_arg); |
| return reinterpret_cast<void*>(static_cast<uintptr_t>(do_action(arg))); |
| } |
| |
| noinline int do_action_on_thread(const char* arg) { |
| pthread_t t; |
| pthread_create(&t, nullptr, thread_callback, const_cast<char*>(arg)); |
| void* result = nullptr; |
| pthread_join(t, &result); |
| return reinterpret_cast<uintptr_t>(result); |
| } |
| |
| noinline int crash_null() { |
| int (*null_func)() = nullptr; |
| return null_func(); |
| } |
| |
| noinline int crash3(int a) { |
| *reinterpret_cast<int*>(0xdead) = a; |
| return a*4; |
| } |
| |
| noinline int crash2(int a) { |
| a = crash3(a) + 2; |
| return a*3; |
| } |
| |
| noinline int crash(int a) { |
| a = crash2(a) + 1; |
| return a*2; |
| } |
| |
| #pragma clang diagnostic push |
| #pragma clang diagnostic ignored "-Wfree-nonheap-object" |
| |
| noinline void abuse_heap() { |
| char buf[16]; |
| free(buf); // GCC is smart enough to warn about this, but we're doing it deliberately. |
| } |
| #pragma clang diagnostic pop |
| |
| noinline void leak() { |
| while (true) { |
| void* mapping = |
| mmap(nullptr, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| static_cast<volatile char*>(mapping)[0] = 'a'; |
| } |
| } |
| |
| noinline void sigsegv_non_null() { |
| int* a = (int *)(&do_action); |
| *a = 42; |
| } |
| |
| noinline void fprintf_null() { |
| FILE* sneaky_null = nullptr; |
| fprintf(sneaky_null, "oops"); |
| } |
| |
| noinline void readdir_null() { |
| DIR* sneaky_null = nullptr; |
| readdir(sneaky_null); |
| } |
| |
| noinline int strlen_null() { |
| char* sneaky_null = nullptr; |
| return strlen(sneaky_null); |
| } |
| |
| static int usage() { |
| fprintf(stderr, "usage: %s KIND\n", getprogname()); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, "where KIND is:\n"); |
| fprintf(stderr, " smash-stack overwrite a -fstack-protector guard\n"); |
| fprintf(stderr, " stack-overflow recurse until the stack overflows\n"); |
| fprintf(stderr, " nostack crash with a NULL stack pointer\n"); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, " heap-usage cause a libc abort by abusing a heap function\n"); |
| fprintf(stderr, " call-null cause a crash by calling through a nullptr\n"); |
| fprintf(stderr, " leak leak memory until we get OOM-killed\n"); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, " abort call abort()\n"); |
| fprintf(stderr, " abort_with_msg call abort() setting an abort message\n"); |
| fprintf(stderr, " abort_with_null_msg call abort() setting a null abort message\n"); |
| fprintf(stderr, " assert call assert() without a function\n"); |
| fprintf(stderr, " assert2 call assert() with a function\n"); |
| fprintf(stderr, " exit call exit(1)\n"); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, " fortify fail a _FORTIFY_SOURCE check\n"); |
| fprintf(stderr, " fdsan_file close a file descriptor that's owned by a FILE*\n"); |
| fprintf(stderr, " fdsan_dir close a file descriptor that's owned by a DIR*\n"); |
| fprintf(stderr, " seccomp fail a seccomp check\n"); |
| #if defined(__arm__) |
| fprintf(stderr, " kuser_helper_version call kuser_helper_version\n"); |
| fprintf(stderr, " kuser_get_tls call kuser_get_tls\n"); |
| fprintf(stderr, " kuser_cmpxchg call kuser_cmpxchg\n"); |
| fprintf(stderr, " kuser_memory_barrier call kuser_memory_barrier\n"); |
| fprintf(stderr, " kuser_cmpxchg64 call kuser_cmpxchg64\n"); |
| #endif |
| fprintf(stderr, " xom read execute-only memory\n"); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, " LOG_ALWAYS_FATAL call liblog LOG_ALWAYS_FATAL\n"); |
| fprintf(stderr, " LOG_ALWAYS_FATAL_IF call liblog LOG_ALWAYS_FATAL_IF\n"); |
| fprintf(stderr, " LOG-FATAL call libbase LOG(FATAL)\n"); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, " SIGFPE cause a SIGFPE\n"); |
| fprintf(stderr, " SIGILL cause a SIGILL\n"); |
| fprintf(stderr, " SIGSEGV cause a SIGSEGV at address 0x0 (synonym: crash)\n"); |
| fprintf(stderr, " SIGSEGV-non-null cause a SIGSEGV at a non-zero address\n"); |
| fprintf(stderr, " SIGSEGV-unmapped mmap/munmap a region of memory and then attempt to access it\n"); |
| fprintf(stderr, " SIGTRAP cause a SIGTRAP\n"); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, " fprintf-NULL pass a null pointer to fprintf\n"); |
| fprintf(stderr, " readdir-NULL pass a null pointer to readdir\n"); |
| fprintf(stderr, " strlen-NULL pass a null pointer to strlen\n"); |
| fprintf(stderr, " pthread_join-NULL pass a null pointer to pthread_join\n"); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, " no_new_privs set PR_SET_NO_NEW_PRIVS and then abort\n"); |
| fprintf(stderr, "\n"); |
| fprintf(stderr, "prefix any of the above with 'thread-' to run on a new thread\n"); |
| fprintf(stderr, "prefix any of the above with 'exhaustfd-' to exhaust\n"); |
| fprintf(stderr, "all available file descriptors before crashing.\n"); |
| fprintf(stderr, "prefix any of the above with 'wait-' to wait until input is received on stdin\n"); |
| |
| return EXIT_FAILURE; |
| } |
| |
| noinline int do_action(const char* arg) { |
| // Prefixes. |
| if (!strncmp(arg, "wait-", strlen("wait-"))) { |
| char buf[1]; |
| UNUSED(TEMP_FAILURE_RETRY(read(STDIN_FILENO, buf, sizeof(buf)))); |
| return do_action(arg + strlen("wait-")); |
| } else if (!strncmp(arg, "exhaustfd-", strlen("exhaustfd-"))) { |
| errno = 0; |
| while (errno != EMFILE) { |
| open("/dev/null", O_RDONLY); |
| } |
| return do_action(arg + strlen("exhaustfd-")); |
| } else if (!strncmp(arg, "thread-", strlen("thread-"))) { |
| return do_action_on_thread(arg + strlen("thread-")); |
| } |
| |
| // Actions. |
| if (!strcasecmp(arg, "SIGSEGV-non-null")) { |
| sigsegv_non_null(); |
| } else if (!strcasecmp(arg, "smash-stack")) { |
| volatile int len = 128; |
| return smash_stack(&len); |
| } else if (!strcasecmp(arg, "stack-overflow")) { |
| overflow_stack(nullptr); |
| } else if (!strcasecmp(arg, "nostack")) { |
| crashnostack(); |
| } else if (!strcasecmp(arg, "exit")) { |
| exit(1); |
| } else if (!strcasecmp(arg, "call-null")) { |
| return crash_null(); |
| } else if (!strcasecmp(arg, "crash") || !strcmp(arg, "SIGSEGV")) { |
| return crash(42); |
| } else if (!strcasecmp(arg, "abort")) { |
| maybe_abort(); |
| } else if (!strcasecmp(arg, "abort_with_msg")) { |
| android_set_abort_message("Aborting due to crasher"); |
| maybe_abort(); |
| } else if (!strcasecmp(arg, "abort_with_null")) { |
| android_set_abort_message(nullptr); |
| maybe_abort(); |
| } else if (!strcasecmp(arg, "assert")) { |
| __assert("some_file.c", 123, "false"); |
| } else if (!strcasecmp(arg, "assert2")) { |
| __assert2("some_file.c", 123, "some_function", "false"); |
| #if !defined(__clang_analyzer__) |
| } else if (!strcasecmp(arg, "fortify")) { |
| // FORTIFY is disabled when running clang-tidy and other tools, so this |
| // shouldn't depend on internal implementation details of it. |
| char buf[10]; |
| __read_chk(-1, buf, 32, 10); |
| while (true) pause(); |
| #endif |
| } else if (!strcasecmp(arg, "fdsan_file")) { |
| FILE* f = fopen("/dev/null", "r"); |
| close(fileno(f)); |
| } else if (!strcasecmp(arg, "fdsan_dir")) { |
| DIR* d = opendir("/dev/"); |
| close(dirfd(d)); |
| } else if (!strcasecmp(arg, "LOG(FATAL)")) { |
| LOG(FATAL) << "hello " << 123; |
| } else if (!strcasecmp(arg, "LOG_ALWAYS_FATAL")) { |
| LOG_ALWAYS_FATAL("hello %s", "world"); |
| } else if (!strcasecmp(arg, "LOG_ALWAYS_FATAL_IF")) { |
| LOG_ALWAYS_FATAL_IF(true, "hello %s", "world"); |
| } else if (!strcasecmp(arg, "SIGFPE")) { |
| raise(SIGFPE); |
| return EXIT_SUCCESS; |
| } else if (!strcasecmp(arg, "SIGILL")) { |
| #if defined(__aarch64__) |
| __asm__ volatile(".word 0\n"); |
| #elif defined(__arm__) |
| __asm__ volatile(".word 0xe7f0def0\n"); |
| #elif defined(__i386__) || defined(__x86_64__) |
| __asm__ volatile("ud2\n"); |
| #elif defined(__riscv) |
| __asm__ volatile("unimp\n"); |
| #else |
| #error |
| #endif |
| } else if (!strcasecmp(arg, "SIGTRAP")) { |
| raise(SIGTRAP); |
| return EXIT_SUCCESS; |
| } else if (!strcasecmp(arg, "fprintf-NULL")) { |
| fprintf_null(); |
| } else if (!strcasecmp(arg, "readdir-NULL")) { |
| readdir_null(); |
| } else if (!strcasecmp(arg, "strlen-NULL")) { |
| return strlen_null(); |
| } else if (!strcasecmp(arg, "pthread_join-NULL")) { |
| return pthread_join(0, nullptr); |
| } else if (!strcasecmp(arg, "heap-usage")) { |
| abuse_heap(); |
| } else if (!strcasecmp(arg, "leak")) { |
| leak(); |
| } else if (!strcasecmp(arg, "SIGSEGV-unmapped")) { |
| char* map = reinterpret_cast<char*>( |
| mmap(nullptr, sizeof(int), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0)); |
| munmap(map, sizeof(int)); |
| map[0] = '8'; |
| } else if (!strcasecmp(arg, "seccomp")) { |
| set_system_seccomp_filter(); |
| syscall(99999); |
| #if defined(__LP64__) |
| } else if (!strcasecmp(arg, "xom")) { |
| // Try to read part of our code, which will fail if XOM is active. |
| printf("*%lx = %lx\n", reinterpret_cast<long>(usage), *reinterpret_cast<long*>(usage)); |
| #endif |
| #if defined(__arm__) |
| } else if (!strcasecmp(arg, "kuser_helper_version")) { |
| return __kuser_helper_version; |
| } else if (!strcasecmp(arg, "kuser_get_tls")) { |
| return !__kuser_get_tls(); |
| } else if (!strcasecmp(arg, "kuser_cmpxchg")) { |
| return __kuser_cmpxchg(0, 0, 0); |
| } else if (!strcasecmp(arg, "kuser_memory_barrier")) { |
| __kuser_dmb(); |
| } else if (!strcasecmp(arg, "kuser_cmpxchg64")) { |
| return __kuser_cmpxchg64(0, 0, 0); |
| #endif |
| } else if (!strcasecmp(arg, "no_new_privs")) { |
| if (prctl(PR_SET_NO_NEW_PRIVS, 1) != 0) { |
| fprintf(stderr, "prctl(PR_SET_NO_NEW_PRIVS, 1) failed: %s\n", strerror(errno)); |
| return EXIT_SUCCESS; |
| } |
| abort(); |
| } else { |
| return usage(); |
| } |
| |
| fprintf(stderr, "%s: exiting normally!\n", getprogname()); |
| return EXIT_SUCCESS; |
| } |
| |
| int main(int argc, char** argv) { |
| #if defined(STATIC_CRASHER) |
| debuggerd_callbacks_t callbacks = { |
| .get_process_info = []() { |
| static struct { |
| size_t size; |
| char msg[32]; |
| } msg; |
| |
| msg.size = strlen("dummy abort message"); |
| memcpy(msg.msg, "dummy abort message", strlen("dummy abort message")); |
| return debugger_process_info{ |
| .abort_msg = reinterpret_cast<void*>(&msg), |
| }; |
| }, |
| .post_dump = nullptr |
| }; |
| debuggerd_init(&callbacks); |
| #endif |
| |
| if (argc == 1) crash1(); |
| else if (argc == 2) return do_action(argv[1]); |
| |
| return usage(); |
| } |
| |
| }; |