#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/cdefs.h>
#include <sys/mman.h>
#include <sys/ptrace.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>
#include <cutils/sockets.h>
#include <log/log.h>
#ifndef __unused
#define __unused __attribute__((__unused__))
#endif
extern const char* __progname;
void crash1(void);
void crashnostack(void);
static int do_action(const char* arg);
static void maybe_abort() {
if (time(0) != 42) {
abort();
}
}
static int smash_stack(int i __unused) {
printf("crasher: deliberately corrupting stack...\n");
// Unless there's a "big enough" buffer on the stack, gcc
// doesn't bother inserting checks.
char buf[8];
// If we don't write something relatively unpredictable
// into the buffer and then do something with it, gcc
// optimizes everything away and just returns a constant.
*(int*)(&buf[7]) = (uintptr_t) &buf[0];
return *(int*)(&buf[0]);
}
static void* global = 0; // So GCC doesn't optimize the tail recursion out of overflow_stack.
__attribute__((noinline)) static void overflow_stack(void* p) {
void* buf[1];
buf[0] = p;
global = buf;
overflow_stack(&buf);
}
static void *noisy(void *x)
{
char c = (uintptr_t) x;
for(;;) {
usleep(250*1000);
write(2, &c, 1);
if(c == 'C') *((unsigned*) 0) = 42;
}
return NULL;
}
static int ctest()
{
pthread_t thr;
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
pthread_create(&thr, &attr, noisy, (void*) 'A');
pthread_create(&thr, &attr, noisy, (void*) 'B');
pthread_create(&thr, &attr, noisy, (void*) 'C');
for(;;) ;
return 0;
}
static void* thread_callback(void* raw_arg)
{
return (void*) (uintptr_t) do_action((const char*) raw_arg);
}
static int do_action_on_thread(const char* arg)
{
pthread_t t;
pthread_create(&t, NULL, thread_callback, (void*) arg);
void* result = NULL;
pthread_join(t, &result);
return (int) (uintptr_t) result;
}
__attribute__((noinline)) static int crash3(int a) {
*((int*) 0xdead) = a;
return a*4;
}
__attribute__((noinline)) static int crash2(int a) {
a = crash3(a) + 2;
return a*3;
}
__attribute__((noinline)) static int crash(int a) {
a = crash2(a) + 1;
return a*2;
}
static void abuse_heap() {
char buf[16];
free((void*) buf); // GCC is smart enough to warn about this, but we're doing it deliberately.
}
static void sigsegv_non_null() {
int* a = (int *)(&do_action);
*a = 42;
}
static int do_action(const char* arg)
{
fprintf(stderr,"crasher: init pid=%d tid=%d\n", getpid(), gettid());
if (!strncmp(arg, "thread-", strlen("thread-"))) {
return do_action_on_thread(arg + strlen("thread-"));
} else if (!strcmp(arg, "SIGSEGV-non-null")) {
sigsegv_non_null();
} else if (!strcmp(arg, "smash-stack")) {
return smash_stack(42);
} else if (!strcmp(arg, "stack-overflow")) {
overflow_stack(NULL);
} else if (!strcmp(arg, "nostack")) {
crashnostack();
} else if (!strcmp(arg, "ctest")) {
return ctest();
} else if (!strcmp(arg, "exit")) {
exit(1);
} else if (!strcmp(arg, "crash") || !strcmp(arg, "SIGSEGV")) {
return crash(42);
} else if (!strcmp(arg, "abort")) {
maybe_abort();
} else if (!strcmp(arg, "assert")) {
__assert("some_file.c", 123, "false");
} else if (!strcmp(arg, "assert2")) {
__assert2("some_file.c", 123, "some_function", "false");
} else if (!strcmp(arg, "LOG_ALWAYS_FATAL")) {
LOG_ALWAYS_FATAL("hello %s", "world");
} else if (!strcmp(arg, "LOG_ALWAYS_FATAL_IF")) {
LOG_ALWAYS_FATAL_IF(true, "hello %s", "world");
} else if (!strcmp(arg, "SIGFPE")) {
raise(SIGFPE);
return EXIT_SUCCESS;
} else if (!strcmp(arg, "SIGPIPE")) {
int pipe_fds[2];
pipe(pipe_fds);
close(pipe_fds[0]);
write(pipe_fds[1], "oops", 4);
return EXIT_SUCCESS;
} else if (!strcmp(arg, "SIGTRAP")) {
raise(SIGTRAP);
return EXIT_SUCCESS;
} else if (!strcmp(arg, "heap-usage")) {
abuse_heap();
} else if (!strcmp(arg, "SIGSEGV-unmapped")) {
char* map = mmap(NULL, sizeof(int), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
munmap(map, sizeof(int));
map[0] = '8';
}
fprintf(stderr, "%s OP\n", __progname);
fprintf(stderr, "where OP is:\n");
fprintf(stderr, " smash-stack overwrite a stack-guard canary\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, " ctest (obsoleted by thread-crash?)\n");
fprintf(stderr, " exit call exit(1)\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, " LOG_ALWAYS_FATAL call LOG_ALWAYS_FATAL\n");
fprintf(stderr, " LOG_ALWAYS_FATAL_IF call LOG_ALWAYS_FATAL\n");
fprintf(stderr, " SIGFPE cause a SIGFPE\n");
fprintf(stderr, " SIGPIPE cause a SIGPIPE\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, "prefix any of the above with 'thread-' to not run\n");
fprintf(stderr, "on the process' main thread.\n");
return EXIT_SUCCESS;
}
int main(int argc, char **argv)
{
fprintf(stderr,"crasher: built at " __TIME__ "!@\n");
if(argc > 1) {
return do_action(argv[1]);
} else {
crash1();
}
return 0;
}