// https://syzkaller.appspot.com/bug?id=cd2a427abfbf4e92ead7ada51dc4e48fe160bc95 // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include static __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* ctx) { uintptr_t addr = (uintptr_t)info->si_addr; const uintptr_t prog_start = 1 << 20; const uintptr_t prog_end = 100 << 20; if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && (addr < prog_start || addr > prog_end)) { _longjmp(segv_env, 1); } exit(sig); } static void install_segv_handler(void) { struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_handler = SIG_IGN; syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8); syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8); memset(&sa, 0, sizeof(sa)); sa.sa_sigaction = segv_handler; sa.sa_flags = SA_NODEFER | SA_SIGINFO; sigaction(SIGSEGV, &sa, NULL); sigaction(SIGBUS, &sa, NULL); } #define NONFAILING(...) \ { \ __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ if (_setjmp(segv_env) == 0) { \ __VA_ARGS__; \ } \ __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ } static void sleep_ms(uint64_t ms) { usleep(ms * 1000); } static uint64_t current_time_ms(void) { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) exit(1); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } static void thread_start(void* (*fn)(void*), void* arg) { pthread_t th; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setstacksize(&attr, 128 << 10); int i; for (i = 0; i < 100; i++) { if (pthread_create(&th, &attr, fn, arg) == 0) { pthread_attr_destroy(&attr); return; } if (errno == EAGAIN) { usleep(50); continue; } break; } exit(1); } typedef struct { int state; } event_t; static void event_init(event_t* ev) { ev->state = 0; } static void event_reset(event_t* ev) { ev->state = 0; } static void event_set(event_t* ev) { if (ev->state) exit(1); __atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE); syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000); } static void event_wait(event_t* ev) { while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0); } static int event_isset(event_t* ev) { return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE); } static int event_timedwait(event_t* ev, uint64_t timeout) { uint64_t start = current_time_ms(); uint64_t now = start; for (;;) { uint64_t remain = timeout - (now - start); struct timespec ts; ts.tv_sec = remain / 1000; ts.tv_nsec = (remain % 1000) * 1000 * 1000; syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts); if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) return 1; now = current_time_ms(); if (now - start > timeout) return 0; } } struct thread_t { int created, call; event_t ready, done; }; static struct thread_t threads[16]; static void execute_call(int call); static int running; static void* thr(void* arg) { struct thread_t* th = (struct thread_t*)arg; for (;;) { event_wait(&th->ready); event_reset(&th->ready); execute_call(th->call); __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED); event_set(&th->done); } return 0; } static void loop(void) { int i, call, thread; for (call = 0; call < 2; call++) { for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0])); thread++) { struct thread_t* th = &threads[thread]; if (!th->created) { th->created = 1; event_init(&th->ready); event_init(&th->done); event_set(&th->done); thread_start(thr, th); } if (!event_isset(&th->done)) continue; event_reset(&th->done); th->call = call; __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED); event_set(&th->ready); event_timedwait(&th->done, 45); break; } } for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++) sleep_ms(1); } uint64_t r[1] = {0xffffffffffffffff}; void execute_call(int call) { intptr_t res = 0; switch (call) { case 0: NONFAILING(memcpy((void*)0x20000180, "/dev/fb0\000", 9)); res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000180ul, 0ul, 0ul); if (res != -1) r[0] = res; break; case 1: NONFAILING(*(uint32_t*)0x200001c0 = 0x40); NONFAILING(*(uint32_t*)0x200001c4 = 0); NONFAILING(*(uint32_t*)0x200001c8 = 0); NONFAILING(*(uint32_t*)0x200001cc = 0x960); NONFAILING(*(uint32_t*)0x200001d0 = 0); NONFAILING(*(uint32_t*)0x200001d4 = 0); NONFAILING(*(uint32_t*)0x200001d8 = 4); NONFAILING(*(uint32_t*)0x200001dc = 0); NONFAILING(*(uint32_t*)0x200001e0 = 0); NONFAILING(*(uint32_t*)0x200001e4 = 0); NONFAILING(*(uint32_t*)0x200001e8 = 0); NONFAILING(*(uint32_t*)0x200001ec = 0); NONFAILING(*(uint32_t*)0x200001f0 = 0); NONFAILING(*(uint32_t*)0x200001f4 = 0); NONFAILING(*(uint32_t*)0x200001f8 = 0); NONFAILING(*(uint32_t*)0x200001fc = 0); NONFAILING(*(uint32_t*)0x20000200 = 0); NONFAILING(*(uint32_t*)0x20000204 = 0); NONFAILING(*(uint32_t*)0x20000208 = 0); NONFAILING(*(uint32_t*)0x2000020c = 0); NONFAILING(*(uint32_t*)0x20000210 = 2); NONFAILING(*(uint32_t*)0x20000214 = 0); NONFAILING(*(uint32_t*)0x20000218 = 0); NONFAILING(*(uint32_t*)0x2000021c = 0); NONFAILING(*(uint32_t*)0x20000220 = 0); NONFAILING(*(uint32_t*)0x20000224 = 0); NONFAILING(*(uint32_t*)0x20000228 = 0); NONFAILING(*(uint32_t*)0x2000022c = 0); NONFAILING(*(uint32_t*)0x20000230 = 0); NONFAILING(*(uint32_t*)0x20000234 = 0); NONFAILING(*(uint32_t*)0x20000238 = 0); NONFAILING(*(uint32_t*)0x2000023c = 0); NONFAILING(*(uint32_t*)0x20000240 = 0); NONFAILING(*(uint32_t*)0x20000244 = 0); NONFAILING(*(uint32_t*)0x20000248 = 0); NONFAILING(*(uint32_t*)0x2000024c = 0); NONFAILING(*(uint32_t*)0x20000250 = 0); NONFAILING(*(uint32_t*)0x20000254 = 0); NONFAILING(*(uint32_t*)0x20000258 = 0); NONFAILING(*(uint32_t*)0x2000025c = 0); syscall(__NR_ioctl, r[0], 0x4601, 0x200001c0ul); break; } } int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); install_segv_handler(); loop(); return 0; }