// https://syzkaller.appspot.com/bug?id=a74718ca902617e6aa7327aa008b25844eccf2d3 // 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 #include #include #include #include unsigned long long procid; 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_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 kill_and_wait(int pid, int* status) { kill(pid, SIGKILL); while (waitpid(-1, status, 0) != pid) { } } 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 { pthread_mutex_t mu; pthread_cond_t cv; int state; } event_t; static void event_init(event_t* ev) { if (pthread_mutex_init(&ev->mu, 0)) exit(1); if (pthread_cond_init(&ev->cv, 0)) exit(1); ev->state = 0; } static void event_reset(event_t* ev) { ev->state = 0; } static void event_set(event_t* ev) { pthread_mutex_lock(&ev->mu); if (ev->state) exit(1); ev->state = 1; pthread_mutex_unlock(&ev->mu); pthread_cond_broadcast(&ev->cv); } static void event_wait(event_t* ev) { pthread_mutex_lock(&ev->mu); while (!ev->state) pthread_cond_wait(&ev->cv, &ev->mu); pthread_mutex_unlock(&ev->mu); } static int event_isset(event_t* ev) { pthread_mutex_lock(&ev->mu); int res = ev->state; pthread_mutex_unlock(&ev->mu); return res; } static int event_timedwait(event_t* ev, uint64_t timeout) { uint64_t start = current_time_ms(); uint64_t now = start; pthread_mutex_lock(&ev->mu); for (;;) { if (ev->state) break; uint64_t remain = timeout - (now - start); struct timespec ts; ts.tv_sec = remain / 1000; ts.tv_nsec = (remain % 1000) * 1000 * 1000; pthread_cond_timedwait(&ev->cv, &ev->mu, &ts); now = current_time_ms(); if (now - start > timeout) break; } int res = ev->state; pthread_mutex_unlock(&ev->mu); return res; } #define __syscall syscall static void sandbox_common() { if (setsid() == -1) exit(1); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = 8 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_FSIZE, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_STACK, &rlim); rlim.rlim_cur = rlim.rlim_max = 0; setrlimit(RLIMIT_CORE, &rlim); rlim.rlim_cur = rlim.rlim_max = 256; setrlimit(RLIMIT_NOFILE, &rlim); } static void loop(); static int do_sandbox_none(void) { sandbox_common(); loop(); 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 execute_one(void) { int i, call, thread; int collide = 0; again: for (call = 0; call < 9; 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); if (collide && (call % 2) == 0) break; event_timedwait(&th->done, 45); break; } } for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++) sleep_ms(1); if (!collide) { collide = 1; goto again; } } static void execute_one(void); #define WAIT_FLAGS 0 static void loop(void) { int iter; for (iter = 0;; iter++) { int pid = fork(); if (pid < 0) exit(1); if (pid == 0) { execute_one(); exit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break; sleep_ms(1); if (current_time_ms() - start < 5 * 1000) continue; kill_and_wait(pid, &status); break; } } } uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff}; void execute_call(int call) { intptr_t res; switch (call) { case 0: NONFAILING(memcpy((void*)0x20000100, "./file0\000", 8)); syscall(SYS_open, 0x20000100, 0x60a, 0); break; case 1: NONFAILING(memcpy((void*)0x20000180, "./file0\000", 8)); syscall(SYS_ktrace, 0x20000180, 0x14, 0xf14, 0); break; case 2: syscall(SYS_execve, 0, 0, 0); break; case 3: NONFAILING(*(uint64_t*)0x20000000 = 0x20000280); NONFAILING(memcpy( (void*)0x20000280, "\xf5\x1b\x9d\x74\x81\x4c\x67\x0d\xfc\xe7\x52\x97\x6d\x8f\xb8\x7a\x9e" "\x0e\xee\x5f\x3b\x6a\xe0\x22\x91\x5b\x01\x76\xd4\x0a\xed\x62\xb0\xca" "\xaf\xb8\x2b\x24\x16\x02\x57\x4a\x85\x2d\x34\xa9\x29\xd1\x3e\xae\x8d" "\x23\x3b\x8f\x2a\xe9\x2c\x02\x66\x1c\x25\x8b\x1a\x8c\xe9\xd2\xa7\x40" "\xbf\xa0\x13\xa5\x53\xbb\x41\x38\x63\x90\xd0\xb5\x58\xb2\xd2\x6a\x20" "\x7b\x87\x84\x88\x01\x4c\xc8\x56\x33\x85\xcd\x4e\xf8\xa6\x8e\x21\xd9" "\x32\x07\x41\xde\xb1\x3e\x42\x9b\xc7\x3c\x63\x51\x91\x64\xc3\x24\xe5" "\x89\x39\x24\xb4\xde\xbe\x18\x02\x86\x57\xf1\x57\x42\xff\xb9\x68\xc5" "\xc8\xdd\xeb\xac\xe1\xdd\xd3\x5b\xa2\x18", 146)); NONFAILING(*(uint64_t*)0x20000008 = 0x92); syscall(SYS_writev, -1, 0x20000000, 1); break; case 4: NONFAILING(memcpy((void*)0x20000300, "tap", 3)); NONFAILING(*(uint8_t*)0x20000303 = 0x30 + procid * 1); NONFAILING(*(uint8_t*)0x20000304 = 0); syscall(SYS_ioctl, -1, 0x8020426c, 0x20000300); break; case 5: syscall(SYS_mprotect, 0x20000000, 0x800000, 4); break; case 6: res = syscall(SYS_socket, 2, 0x400000000002, 0); if (res != -1) r[0] = res; break; case 7: res = syscall(SYS_fcntl, r[0], 0, r[0]); if (res != -1) r[1] = res; break; case 8: NONFAILING(*(uint32_t*)0x20000300 = 0); syscall(SYS_ioctl, r[1], 0x8020690c, 0x20000300); break; } } int main(void) { syscall(SYS_mmap, 0x20000000, 0x1000000, 3, 0x1012, -1, 0, 0); install_segv_handler(); for (procid = 0; procid < 2; procid++) { if (fork() == 0) { do_sandbox_none(); } } sleep(1000000); return 0; }