// https://syzkaller.appspot.com/bug?id=dd34fb19cb7b33bf40f1703ba937145db4e6d65f // autogenerated by syzkaller (http://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include __attribute__((noreturn)) static void doexit(int status) { volatile unsigned i; syscall(__NR_exit_group, status); for (i = 0;; i++) { } } #include #include #include #include #include #include #include #include #include #include const int kFailStatus = 67; const int kRetryStatus = 69; static void fail(const char* msg, ...) { int e = errno; va_list args; va_start(args, msg); vfprintf(stderr, msg, args); va_end(args); fprintf(stderr, " (errno %d)\n", e); doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus); } static __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* uctx) { 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); } doexit(sig); for (;;) { } } static void install_segv_handler() { 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 use_temporary_dir() { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) fail("failed to mkdtemp"); if (chmod(tmpdir, 0777)) fail("failed to chmod"); if (chdir(tmpdir)) fail("failed to chdir"); } static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2) { if (a0 == 0xc || a0 == 0xb) { char buf[128]; sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, (uint8_t)a2); return open(buf, O_RDWR, 0); } else { char buf[1024]; char* hash; NONFAILING(strncpy(buf, (char*)a0, sizeof(buf))); buf[sizeof(buf) - 1] = 0; while ((hash = strchr(buf, '#'))) { *hash = '0' + (char)(a1 % 10); a1 /= 10; } return open(buf, a2, 0); } } static void test(); void loop() { while (1) { test(); } } #ifndef __NR_mmap #define __NR_mmap 192 #endif #ifndef __NR_pipe2 #define __NR_pipe2 331 #endif #ifndef __NR_splice #define __NR_splice 313 #endif #ifndef __NR_ioctl #define __NR_ioctl 54 #endif #undef __NR_mmap #define __NR_mmap __NR_mmap2 long r[2]; void* thr(void* arg) { switch ((long)arg) { case 0: syscall(__NR_mmap, 0x20000000ul, 0xfff000ul, 0x3ul, 0x32ul, 0xfffffffffffffffful, 0x0ul); break; case 1: if (syscall(__NR_pipe2, 0x20360ff8ul, 0x0ul) != -1) { NONFAILING(r[0] = *(uint32_t*)0x20360ffc); } break; case 2: NONFAILING(memcpy((void*)0x20000000, "/dev/sg#", 9)); r[1] = syz_open_dev(0x20000000ul, 0x0ul, 0x0ul); break; case 3: syscall(__NR_splice, r[1], 0x0ul, r[0], 0x0ul, 0xfffffffffffffffeul, 0x0ul); break; case 4: NONFAILING(*(uint64_t*)0x20837ff8 = (uint64_t)0x7); syscall(__NR_ioctl, r[1], 0x5452ul, 0x20837ff8ul); break; } return 0; } void test() { long i; pthread_t th[10]; memset(r, -1, sizeof(r)); for (i = 0; i < 5; i++) { pthread_create(&th[i], 0, thr, (void*)i); usleep(rand() % 10000); } usleep(rand() % 100000); } int main() { int i; for (i = 0; i < 8; i++) { if (fork() == 0) { install_segv_handler(); use_temporary_dir(); loop(); return 0; } } sleep(1000000); return 0; }