// https://syzkaller.appspot.com/bug?id=2bf7b7983c2398ec6f0c4c6c87cb50223e8873f8 // autogenerated by syzkaller (http://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #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 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); } 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 uint64_t current_time_ms() { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) fail("clock_gettime failed"); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } static void test(); void loop() { int iter; for (iter = 0;; iter++) { int pid = fork(); if (pid < 0) fail("loop fork failed"); if (pid == 0) { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); test(); doexit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { int res = waitpid(-1, &status, __WALL | WNOHANG); if (res == pid) break; usleep(1000); if (current_time_ms() - start > 5 * 1000) { kill(-pid, SIGKILL); kill(pid, SIGKILL); while (waitpid(-1, &status, __WALL) != pid) { } break; } } } } struct thread_t { int created, running, call; pthread_t th; }; static struct thread_t threads[16]; static void execute_call(int call); static int running; static int collide; static void* thr(void* arg) { struct thread_t* th = (struct thread_t*)arg; for (;;) { while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0); execute_call(th->call); __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED); __atomic_store_n(&th->running, 0, __ATOMIC_RELEASE); syscall(SYS_futex, &th->running, FUTEX_WAKE); } return 0; } static void execute(int num_calls) { int call, thread; running = 0; for (call = 0; call < num_calls; call++) { for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) { struct thread_t* th = &threads[thread]; if (!th->created) { th->created = 1; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setstacksize(&attr, 128 << 10); pthread_create(&th->th, &attr, thr, th); } if (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) { th->call = call; __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED); __atomic_store_n(&th->running, 1, __ATOMIC_RELEASE); syscall(SYS_futex, &th->running, FUTEX_WAKE); if (collide && call % 2) break; struct timespec ts; ts.tv_sec = 0; ts.tv_nsec = 20 * 1000 * 1000; syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts); if (running) usleep((call == num_calls - 1) ? 10000 : 1000); break; } } } } #ifndef __NR_socket #define __NR_socket 359 #endif #ifndef __NR_mmap #define __NR_mmap 192 #endif #ifndef __NR_openat #define __NR_openat 295 #endif #ifndef __NR_getsockopt #define __NR_getsockopt 365 #endif #ifndef __NR_ioctl #define __NR_ioctl 54 #endif #undef __NR_mmap #define __NR_mmap __NR_mmap2 long r[5]; void execute_call(int call) { switch (call) { case 0: syscall(__NR_ioctl, -1, 0x40046205, 4); break; case 1: r[0] = syscall(__NR_socket, 0x1f, 3, 0); break; case 2: syscall(__NR_mmap, 0x20001000, 0x1000, 3, 0x32, -1, 0); break; case 3: NONFAILING(memcpy( (void*)0x20001000, "\xe8\x2b\xa3\xa5\x35\x0b\x56\xe5\x98\x56\xc0\x26\x63\x08\xc8\x2f", 16)); NONFAILING(*(uint16_t*)0x20001010 = 0x4202); syscall(__NR_ioctl, r[0], 0x8935, 0x20001000); break; case 4: NONFAILING(memcpy((void*)0x2025f000, "/selinux/commit_pending_bools", 30)); r[1] = syscall(__NR_openat, 0xffffff9c, 0x2025f000, 1, 0); break; case 5: NONFAILING(*(uint64_t*)0x205beff0 = 0xab); NONFAILING(*(uint64_t*)0x205beff8 = 3); syscall(__NR_ioctl, r[1], 0x4010640d, 0x205beff0); break; case 6: NONFAILING(*(uint32_t*)0x20081ff0 = 0); NONFAILING(*(uint16_t*)0x20081ff4 = -1); NONFAILING(*(uint16_t*)0x20081ff6 = 4); NONFAILING(*(uint16_t*)0x20081ff8 = 0); NONFAILING(*(uint16_t*)0x20081ffa = 0x296e); NONFAILING(*(uint16_t*)0x20081ffc = 0x3ff); NONFAILING(*(uint16_t*)0x20081ffe = 3); NONFAILING(*(uint32_t*)0x20bc3000 = 0x10); syscall(__NR_getsockopt, -1, 0x84, 0x77, 0x20081ff0, 0x20bc3000); break; case 7: syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0); break; case 8: NONFAILING(memcpy((void*)0x20597ff7, "/dev/kvm", 9)); r[2] = syscall(__NR_openat, 0xffffff9c, 0x20597ff7, 0, 0); break; case 9: r[3] = syscall(__NR_ioctl, r[2], 0xae01, 0); break; case 10: syscall(__NR_ioctl, r[3], 0xae47, 0); break; case 11: r[4] = syscall(__NR_ioctl, r[3], 0xae41, 0); break; case 12: syscall(__NR_ioctl, r[4], 0xae80, 0); break; } } void test() { memset(r, -1, sizeof(r)); execute(13); collide = 1; execute(13); } int main() { install_segv_handler(); for (;;) { loop(); } }