// https://syzkaller.appspot.com/bug?id=25b6319de87ee906cb56b0cfc42c0b7543d7c822 // 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 static __thread int clone_ongoing; static __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* ctx) { if (__atomic_load_n(&clone_ongoing, __ATOMIC_RELAXED) != 0) { exit(sig); } uintptr_t addr = (uintptr_t)info->si_addr; const uintptr_t prog_start = 1 << 20; const uintptr_t prog_end = 100 << 20; int skip = __atomic_load_n(&skip_segv, __ATOMIC_RELAXED) != 0; int valid = addr < prog_start || addr > prog_end; if (sig == SIGBUS) valid = 1; if (skip && valid) { _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(...) \ ({ \ int ok = 1; \ __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ if (_setjmp(segv_env) == 0) { \ __VA_ARGS__; \ } else \ ok = 0; \ __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ ok; \ }) 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 = 0; for (; 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; } static void sandbox_common() { struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = 128 << 20; setrlimit(RLIMIT_AS, &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) { if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } int i, call, thread; for (call = 0; call < 8; 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, 50); 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 = 0; for (;; 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 (;;) { sleep_ms(10); if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break; if (current_time_ms() - start < 5000) continue; kill_and_wait(pid, &status); break; } } } uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; void execute_call(int call) { intptr_t res = 0; switch (call) { case 0: // freebsd10_pipe arguments: [ // pipefd: ptr[out, pipefd] { // pipefd { // rfd: fd (resource) // wfd: fd (resource) // } // } // ] res = syscall(SYS_freebsd10_pipe, /*pipefd=*/0x2000000001c0ul); if (res != -1) NONFAILING(r[0] = *(uint32_t*)0x2000000001c4); break; case 1: // close arguments: [ // fd: fd (resource) // ] syscall(SYS_close, /*fd=*/r[0]); break; case 2: // socket$unix arguments: [ // domain: const = 0x1 (8 bytes) // type: unix_socket_type = 0x5 (8 bytes) // proto: const = 0x0 (1 bytes) // ] // returns sock_unix res = syscall(SYS_socket, /*domain=*/1ul, /*type=SOCK_SEQPACKET*/ 5ul, /*proto=*/0); if (res != -1) r[1] = res; break; case 3: // bind$unix arguments: [ // fd: sock_unix (resource) // addr: ptr[in, sockaddr_un] { // union sockaddr_un { // file: sockaddr_un_file { // len: len = 0xa (1 bytes) // family: unix_socket_family = 0x1 (1 bytes) // path: buffer: {2e 2f 66 69 6c 65 31 00} (length 0x8) // } // } // } // addrlen: len = 0xa (8 bytes) // ] NONFAILING(*(uint8_t*)0x2000000002c0 = 0xa); NONFAILING(*(uint8_t*)0x2000000002c1 = 1); NONFAILING(memcpy((void*)0x2000000002c2, "./file1\000", 8)); syscall(SYS_bind, /*fd=*/r[1], /*addr=*/0x2000000002c0ul, /*addrlen=*/0xaul); break; case 4: // listen arguments: [ // fd: sock (resource) // backlog: int32 = 0xfffffffe (4 bytes) // ] syscall(SYS_listen, /*fd=*/r[1], /*backlog=*/0xfffffffe); break; case 5: // sendmsg$unix arguments: [ // fd: sock_unix (resource) // msg: ptr[in, msghdr_un] { // msghdr_un { // addr: nil // addrlen: len = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // vec: nil // vlen: len = 0x0 (8 bytes) // ctrl: ptr[inout, array[ANYUNION]] { // array[ANYUNION] { // union ANYUNION { // ANYBLOB: buffer: {89 00 00 00 ff ff 00 00 01} (length 0x9) // } // } // } // ctrllen: bytesize = 0x9 (8 bytes) // f: send_flags = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // } // } // f: send_flags = 0x0 (8 bytes) // ] NONFAILING(*(uint64_t*)0x200000000080 = 0); NONFAILING(*(uint32_t*)0x200000000088 = 0); NONFAILING(*(uint64_t*)0x200000000090 = 0); NONFAILING(*(uint64_t*)0x200000000098 = 0); NONFAILING(*(uint64_t*)0x2000000000a0 = 0x200000000000); NONFAILING(memcpy((void*)0x200000000000, "\x89\x00\x00\x00\xff\xff\x00\x00\x01", 9)); NONFAILING(*(uint64_t*)0x2000000000a8 = 9); NONFAILING(*(uint32_t*)0x2000000000b0 = 0); syscall(SYS_sendmsg, /*fd=*/(intptr_t)-1, /*msg=*/0x200000000080ul, /*f=*/0ul); break; case 6: // socketpair$unix arguments: [ // domain: const = 0x1 (8 bytes) // type: unix_socket_type = 0x2 (8 bytes) // proto: const = 0x0 (1 bytes) // fds: ptr[out, unix_pair] { // unix_pair { // fd0: sock_unix (resource) // fd1: sock_unix (resource) // } // } // ] res = syscall(SYS_socketpair, /*domain=*/1ul, /*type=SOCK_DGRAM*/ 2ul, /*proto=*/0, /*fds=*/0x200000000040ul); if (res != -1) NONFAILING(r[2] = *(uint32_t*)0x200000000040); break; case 7: // sendmsg arguments: [ // fd: sock (resource) // msg: ptr[in, send_msghdr] { // send_msghdr { // msg_name: nil // msg_namelen: len = 0x32c (4 bytes) // pad = 0x0 (4 bytes) // msg_iov: nil // msg_iovlen: len = 0x0 (8 bytes) // msg_control: ptr[in, array[cmsghdr]] { // array[cmsghdr] { // } // } // msg_controllen: bytesize = 0x90 (8 bytes) // msg_flags: const = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // } // } // f: send_flags = 0x0 (8 bytes) // ] NONFAILING(*(uint64_t*)0x200000000380 = 0); NONFAILING(*(uint32_t*)0x200000000388 = 0x32c); NONFAILING(*(uint64_t*)0x200000000390 = 0); NONFAILING(*(uint64_t*)0x200000000398 = 0); NONFAILING(*(uint64_t*)0x2000000003a0 = 0x200000000000); NONFAILING(*(uint64_t*)0x2000000003a8 = 0x90); NONFAILING(*(uint32_t*)0x2000000003b0 = 0); syscall(SYS_sendmsg, /*fd=*/r[2], /*msg=*/0x200000000380ul, /*f=*/0ul); break; } } int main(void) { syscall(SYS_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000ul, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x1012ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); const char* reason; (void)reason; install_segv_handler(); do_sandbox_none(); return 0; }