// https://syzkaller.appspot.com/bug?id=820937f1ba9d910e83410c6c0d7678e648413c9a // 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 #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 uintptr_t syz_open_pts(void) { int master, slave; if (openpty(&master, &slave, NULL, NULL, NULL) == -1) return -1; if (dup2(master, master + 100) != -1) close(master); return slave; } 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; for (call = 0; call < 10; 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); } 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[1] = {0xffffffffffffffff}; void execute_call(int call) { long res; switch (call) { case 0: NONFAILING(memcpy((void*)0x20000180, "./file1\000", 8)); res = syscall(SYS_open, 0x20000180, 0x611, 0); if (res != -1) r[0] = res; break; case 1: syscall(SYS_fcntl, r[0], 4, 0xc0); break; case 2: NONFAILING(*(uint64_t*)0x20001600 = 0x200013c0); NONFAILING(*(uint16_t*)0x200013c0 = 1); NONFAILING(*(uint8_t*)0x200013c2 = 0); NONFAILING(*(uint32_t*)0x200013c4 = 0x4e21 + procid * 4); NONFAILING(*(uint32_t*)0x20001608 = 8); NONFAILING(*(uint64_t*)0x20001610 = 0x20001580); NONFAILING(*(uint64_t*)0x20001580 = 0); NONFAILING(*(uint64_t*)0x20001588 = 0); NONFAILING(*(uint64_t*)0x20001590 = 0); NONFAILING(*(uint64_t*)0x20001598 = 0); NONFAILING(*(uint64_t*)0x200015a0 = 0x20001540); NONFAILING(*(uint64_t*)0x200015a8 = 0); NONFAILING(*(uint64_t*)0x20001618 = 3); NONFAILING(*(uint64_t*)0x20001620 = 0x20001740); NONFAILING(*(uint64_t*)0x20001628 = 0); NONFAILING(*(uint32_t*)0x20001630 = 0); syscall(SYS_sendmsg, r[0], 0x20001600, 9); break; case 3: syscall(SYS_fchmod, r[0], 0); break; case 4: syscall(SYS_close, r[0]); break; case 5: NONFAILING(memcpy((void*)0x200000c0, "./file1\000", 8)); NONFAILING(memcpy((void*)0x20000140, "\000\000", 2)); syscall(SYS_unveil, 0x200000c0, 0x20000140); break; case 6: NONFAILING(*(uint32_t*)0x20001200 = 0); syscall(SYS_getpeername, -1, 0, 0x20001200); break; case 7: syscall(SYS_mkdirat, -1, 0, 0x81); break; case 8: NONFAILING(*(uint32_t*)0x20001380 = 0); syscall(SYS_getgroups, 1, 0x20001380); break; case 9: syz_open_pts(); 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) { loop(); } } sleep(1000000); return 0; }