1#include <assert.h>
2#include <errno.h>
3#include <pthread.h>
4#include <sched.h>
5#include <signal.h>
6#include <stdio.h>
7#include <stdlib.h>
8#include <string.h>
9#include <sys/cdefs.h>
10#include <sys/mman.h>
11#include <sys/ptrace.h>
12#include <sys/socket.h>
13#include <sys/wait.h>
14#include <unistd.h>
15
16#include <cutils/sockets.h>
17#include <log/log.h>
18
19#ifndef __unused
20#define __unused __attribute__((__unused__))
21#endif
22
23extern const char* __progname;
24
25void crash1(void);
26void crashnostack(void);
27static int do_action(const char* arg);
28
29static void maybe_abort() {
30    if (time(0) != 42) {
31        abort();
32    }
33}
34
35static char* smash_stack_dummy_buf;
36__attribute__ ((noinline)) static void smash_stack_dummy_function(volatile int* plen) {
37  smash_stack_dummy_buf[*plen] = 0;
38}
39
40// This must be marked with "__attribute__ ((noinline))", to ensure the
41// compiler generates the proper stack guards around this function.
42// Assign local array address to global variable to force stack guards.
43// Use another noinline function to corrupt the stack.
44__attribute__ ((noinline)) static int smash_stack(volatile int* plen) {
45    printf("crasher: deliberately corrupting stack...\n");
46
47    char buf[128];
48    smash_stack_dummy_buf = buf;
49    // This should corrupt stack guards and make process abort.
50    smash_stack_dummy_function(plen);
51    return 0;
52}
53
54static void* global = 0; // So GCC doesn't optimize the tail recursion out of overflow_stack.
55
56__attribute__((noinline)) static void overflow_stack(void* p) {
57    void* buf[1];
58    buf[0] = p;
59    global = buf;
60    overflow_stack(&buf);
61}
62
63static void *noisy(void *x)
64{
65    char c = (uintptr_t) x;
66    for(;;) {
67        usleep(250*1000);
68        write(2, &c, 1);
69        if(c == 'C') *((volatile unsigned*) 0) = 42;
70    }
71    return NULL;
72}
73
74static int ctest()
75{
76    pthread_t thr;
77    pthread_attr_t attr;
78    pthread_attr_init(&attr);
79    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
80    pthread_create(&thr, &attr, noisy, (void*) 'A');
81    pthread_create(&thr, &attr, noisy, (void*) 'B');
82    pthread_create(&thr, &attr, noisy, (void*) 'C');
83    for(;;) ;
84    return 0;
85}
86
87static void* thread_callback(void* raw_arg)
88{
89    return (void*) (uintptr_t) do_action((const char*) raw_arg);
90}
91
92static int do_action_on_thread(const char* arg)
93{
94    pthread_t t;
95    pthread_create(&t, NULL, thread_callback, (void*) arg);
96    void* result = NULL;
97    pthread_join(t, &result);
98    return (int) (uintptr_t) result;
99}
100
101__attribute__((noinline)) static int crash3(int a) {
102    *((int*) 0xdead) = a;
103    return a*4;
104}
105
106__attribute__((noinline)) static int crash2(int a) {
107    a = crash3(a) + 2;
108    return a*3;
109}
110
111__attribute__((noinline)) static int crash(int a) {
112    a = crash2(a) + 1;
113    return a*2;
114}
115
116static void abuse_heap() {
117    char buf[16];
118    free((void*) buf); // GCC is smart enough to warn about this, but we're doing it deliberately.
119}
120
121static void sigsegv_non_null() {
122    int* a = (int *)(&do_action);
123    *a = 42;
124}
125
126static int do_action(const char* arg)
127{
128    fprintf(stderr,"crasher: init pid=%d tid=%d\n", getpid(), gettid());
129
130    if (!strncmp(arg, "thread-", strlen("thread-"))) {
131        return do_action_on_thread(arg + strlen("thread-"));
132    } else if (!strcmp(arg, "SIGSEGV-non-null")) {
133        sigsegv_non_null();
134    } else if (!strcmp(arg, "smash-stack")) {
135        volatile int len = 128;
136        return smash_stack(&len);
137    } else if (!strcmp(arg, "stack-overflow")) {
138        overflow_stack(NULL);
139    } else if (!strcmp(arg, "nostack")) {
140        crashnostack();
141    } else if (!strcmp(arg, "ctest")) {
142        return ctest();
143    } else if (!strcmp(arg, "exit")) {
144        exit(1);
145    } else if (!strcmp(arg, "crash") || !strcmp(arg, "SIGSEGV")) {
146        return crash(42);
147    } else if (!strcmp(arg, "abort")) {
148        maybe_abort();
149    } else if (!strcmp(arg, "assert")) {
150        __assert("some_file.c", 123, "false");
151    } else if (!strcmp(arg, "assert2")) {
152        __assert2("some_file.c", 123, "some_function", "false");
153    } else if (!strcmp(arg, "LOG_ALWAYS_FATAL")) {
154        LOG_ALWAYS_FATAL("hello %s", "world");
155    } else if (!strcmp(arg, "LOG_ALWAYS_FATAL_IF")) {
156        LOG_ALWAYS_FATAL_IF(true, "hello %s", "world");
157    } else if (!strcmp(arg, "SIGFPE")) {
158        raise(SIGFPE);
159        return EXIT_SUCCESS;
160    } else if (!strcmp(arg, "SIGPIPE")) {
161        int pipe_fds[2];
162        pipe(pipe_fds);
163        close(pipe_fds[0]);
164        write(pipe_fds[1], "oops", 4);
165        return EXIT_SUCCESS;
166    } else if (!strcmp(arg, "SIGTRAP")) {
167        raise(SIGTRAP);
168        return EXIT_SUCCESS;
169    } else if (!strcmp(arg, "heap-usage")) {
170        abuse_heap();
171    } else if (!strcmp(arg, "SIGSEGV-unmapped")) {
172        char* map = mmap(NULL, sizeof(int), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
173        munmap(map, sizeof(int));
174        map[0] = '8';
175    }
176
177    fprintf(stderr, "%s OP\n", __progname);
178    fprintf(stderr, "where OP is:\n");
179    fprintf(stderr, "  smash-stack           overwrite a stack-guard canary\n");
180    fprintf(stderr, "  stack-overflow        recurse until the stack overflows\n");
181    fprintf(stderr, "  heap-corruption       cause a libc abort by corrupting the heap\n");
182    fprintf(stderr, "  heap-usage            cause a libc abort by abusing a heap function\n");
183    fprintf(stderr, "  nostack               crash with a NULL stack pointer\n");
184    fprintf(stderr, "  ctest                 (obsoleted by thread-crash?)\n");
185    fprintf(stderr, "  exit                  call exit(1)\n");
186    fprintf(stderr, "  abort                 call abort()\n");
187    fprintf(stderr, "  assert                call assert() without a function\n");
188    fprintf(stderr, "  assert2               call assert() with a function\n");
189    fprintf(stderr, "  LOG_ALWAYS_FATAL      call LOG_ALWAYS_FATAL\n");
190    fprintf(stderr, "  LOG_ALWAYS_FATAL_IF   call LOG_ALWAYS_FATAL\n");
191    fprintf(stderr, "  SIGFPE                cause a SIGFPE\n");
192    fprintf(stderr, "  SIGPIPE               cause a SIGPIPE\n");
193    fprintf(stderr, "  SIGSEGV               cause a SIGSEGV at address 0x0 (synonym: crash)\n");
194    fprintf(stderr, "  SIGSEGV-non-null      cause a SIGSEGV at a non-zero address\n");
195    fprintf(stderr, "  SIGSEGV-unmapped      mmap/munmap a region of memory and then attempt to access it\n");
196    fprintf(stderr, "  SIGTRAP               cause a SIGTRAP\n");
197    fprintf(stderr, "prefix any of the above with 'thread-' to not run\n");
198    fprintf(stderr, "on the process' main thread.\n");
199    return EXIT_SUCCESS;
200}
201
202int main(int argc, char **argv)
203{
204    fprintf(stderr,"crasher: built at " __TIME__ "!@\n");
205
206    if(argc > 1) {
207        return do_action(argv[1]);
208    } else {
209        crash1();
210    }
211
212    return 0;
213}
214