|  | /* | 
|  | * 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 <unistd.h> | 
|  |  | 
|  | // We test both kinds of logging. | 
|  | #include <android/log.h> | 
|  | #include <android-base/logging.h> | 
|  |  | 
|  | #if defined(STATIC_CRASHER) | 
|  | #include "debuggerd/client.h" | 
|  | #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 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; | 
|  | } | 
|  |  | 
|  | noinline void abuse_heap() { | 
|  | char buf[16]; | 
|  | free(buf); // GCC is smart enough to warn about this, but we're doing it deliberately. | 
|  | } | 
|  |  | 
|  | noinline void sigsegv_non_null() { | 
|  | int* a = (int *)(&do_action); | 
|  | *a = 42; | 
|  | } | 
|  |  | 
|  | noinline void fprintf_null() { | 
|  | fprintf(nullptr, "oops"); | 
|  | } | 
|  |  | 
|  | noinline void readdir_null() { | 
|  | readdir(nullptr); | 
|  | } | 
|  |  | 
|  | 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, "  heap-corruption       cause a libc abort by corrupting the heap\n"); | 
|  | fprintf(stderr, "  heap-usage            cause a libc abort by abusing a heap function\n"); | 
|  | fprintf(stderr, "  nostack               crash with a NULL stack pointer\n"); | 
|  | fprintf(stderr, "  abort                 call abort()\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, "  fortify               fail a _FORTIFY_SOURCE check\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, "  SIGFPE                cause a SIGFPE\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, "  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, "\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]; | 
|  | 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, "crash") || !strcmp(arg, "SIGSEGV")) { | 
|  | return crash(42); | 
|  | } else if (!strcasecmp(arg, "abort")) { | 
|  | 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"); | 
|  | } else if (!strcasecmp(arg, "fortify")) { | 
|  | char buf[10]; | 
|  | __read_chk(-1, buf, 32, 10); | 
|  | while (true) pause(); | 
|  | } 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, "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, "heap-usage")) { | 
|  | abuse_heap(); | 
|  | } 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 { | 
|  | 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_abort_message = []() { | 
|  | 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 reinterpret_cast<abort_msg_t*>(&msg); | 
|  | }, | 
|  | .post_dump = nullptr | 
|  | }; | 
|  | debuggerd_init(&callbacks); | 
|  | #endif | 
|  |  | 
|  | if (argc == 1) crash1(); | 
|  | else if (argc == 2) return do_action(argv[1]); | 
|  |  | 
|  | return usage(); | 
|  | } | 
|  |  | 
|  | }; |