// https://syzkaller.appspot.com/bug?id=b96d0a0eaa2196cfa0667e1359772777ee06c80a // 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 #include #include #include #include #include #include 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_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 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 use_temporary_dir(void) { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) exit(1); if (chmod(tmpdir, 0777)) exit(1); if (chdir(tmpdir)) exit(1); } 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); } #define BITMASK(bf_off, bf_len) (((1ull << (bf_len)) - 1) << (bf_off)) #define STORE_BY_BITMASK(type, htobe, addr, val, bf_off, bf_len) \ *(type*)(addr) = \ htobe((htobe(*(type*)(addr)) & ~BITMASK((bf_off), (bf_len))) | \ (((type)(val) << (bf_off)) & BITMASK((bf_off), (bf_len)))) typedef struct { int state; } event_t; static void event_init(event_t* ev) { ev->state = 0; } static void event_reset(event_t* ev) { ev->state = 0; } static void event_set(event_t* ev) { if (ev->state) exit(1); __atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE); syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000); } static void event_wait(event_t* ev) { while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0); } static int event_isset(event_t* ev) { return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE); } static int event_timedwait(event_t* ev, uint64_t timeout) { uint64_t start = current_time_ms(); uint64_t now = start; for (;;) { uint64_t remain = timeout - (now - start); struct timespec ts; ts.tv_sec = remain / 1000; ts.tv_nsec = (remain % 1000) * 1000 * 1000; syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts); if (__atomic_load_n(&ev->state, __ATOMIC_RELAXED)) return 1; now = current_time_ms(); if (now - start > timeout) return 0; } } static bool write_file(const char* file, const char* what, ...) { char buf[1024]; va_list args; va_start(args, what); vsnprintf(buf, sizeof(buf), what, args); va_end(args); buf[sizeof(buf) - 1] = 0; int len = strlen(buf); int fd = open(file, O_WRONLY | O_CLOEXEC); if (fd == -1) return false; if (write(fd, buf, len) != len) { int err = errno; close(fd); errno = err; return false; } close(fd); return true; } #define MAX_FDS 30 static void setup_common() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) { } } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); setsid(); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = (200 << 20); setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 32 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 136 << 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); if (unshare(CLONE_NEWNS)) { } if (unshare(CLONE_NEWIPC)) { } if (unshare(0x02000000)) { } if (unshare(CLONE_NEWUTS)) { } if (unshare(CLONE_SYSVSEM)) { } typedef struct { const char* name; const char* value; } sysctl_t; static const sysctl_t sysctls[] = { {"/proc/sys/kernel/shmmax", "16777216"}, {"/proc/sys/kernel/shmall", "536870912"}, {"/proc/sys/kernel/shmmni", "1024"}, {"/proc/sys/kernel/msgmax", "8192"}, {"/proc/sys/kernel/msgmni", "1024"}, {"/proc/sys/kernel/msgmnb", "1024"}, {"/proc/sys/kernel/sem", "1024 1048576 500 1024"}, }; unsigned i; for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++) write_file(sysctls[i].name, sysctls[i].value); } int wait_for_loop(int pid) { if (pid < 0) exit(1); int status = 0; while (waitpid(-1, &status, __WALL) != pid) { } return WEXITSTATUS(status); } static void drop_caps(void) { struct __user_cap_header_struct cap_hdr = {}; struct __user_cap_data_struct cap_data[2] = {}; cap_hdr.version = _LINUX_CAPABILITY_VERSION_3; cap_hdr.pid = getpid(); if (syscall(SYS_capget, &cap_hdr, &cap_data)) exit(1); const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE); cap_data[0].effective &= ~drop; cap_data[0].permitted &= ~drop; cap_data[0].inheritable &= ~drop; if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1); } static int do_sandbox_none(void) { if (unshare(CLONE_NEWPID)) { } int pid = fork(); if (pid != 0) return wait_for_loop(pid); setup_common(); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } loop(); exit(1); } static void close_fds() { int fd; for (fd = 3; fd < MAX_FDS; fd++) close(fd); } static void setup_binfmt_misc() { if (mount(0, "/proc/sys/fs/binfmt_misc", "binfmt_misc", 0, 0)) { } write_file("/proc/sys/fs/binfmt_misc/register", ":syz0:M:0:\x01::./file0:"); write_file("/proc/sys/fs/binfmt_misc/register", ":syz1:M:1:\x02::./file0:POC"); } 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 loop(void) { int i, call, thread; for (call = 0; call < 4; 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); close_fds(); } uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff}; void execute_call(int call) { intptr_t res; switch (call) { case 0: res = syscall(__NR_socket, 0x10ul, 3ul, 0xcul); if (res != -1) r[0] = res; break; case 1: NONFAILING(*(uint64_t*)0x20000280 = 0); NONFAILING(*(uint32_t*)0x20000288 = 0x2d3); NONFAILING(*(uint64_t*)0x20000290 = 0x20000240); NONFAILING(*(uint64_t*)0x20000240 = 0x200002c0); NONFAILING(memcpy( (void*)0x200002c0, "\x14\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80\x00\x00" "\x00\x00\x0a\x20\x00\x00\x00\x00\x0a\x01\x00\x00\x00\x00\x00\x00\x00" "\x00\x00\x00\x00\x00\x00\x09\x00\x01\x00\x73\x79\x7a\x30\x00\x00\x00" "\x00\x70\x00\x00\x00\x12\x0a\x01\x00\x00\x1f\x34\x01\x04\x00\x00\x00" "\x00\x00\x00\x00\x04\x00\x04\x80\x09\x00\x02\x00\x73\x79\x7a\x30\x00" "\x00\x00\x00\x09\x00\x01\x00\x73\x79\x7a\x30\x00\x00\x00\x00\x08\x00" "\x03\x40\x00\x00\x00\x00\x22\x00\x02\x00\xb7\x63\x12\xc4\x11\x0d\xd9" "\xb1\x73\x79\xe7\x28\x14\x7a\xfe\x6a\xb9\xf3\x2a\xa9\xd1\x45\x55\xfe" "\x00\x30\x00\x00\xfa\x00\x04\x00\x04\x80\x00\x00\x04\x00\x06\x14\x00" "\x04\x80\x09\x00\x01\x00\x59\x79\x7a\x30\x00\x00\x00\x00\x00\x00\x14" "\x00\x00\x00\x11\x00\x6d\x30\xa1\x6e\x90\x01\x6c\x47\x8a\x50\x48\x3a" "\x73\x64\x5a\x6d\xc4\xb5\x34\x5d\x2c\x0d\xb7\x4c\x9f\x89\x67\x8f\xbc" "\x9c\xc6\xfb\x9e\x8e\x31\xfa\xd7\xe7\x58\x0e\x6a\xe4\x35\x8d\x8f\x95" "\xa2\x73\x5d\x57\xdc\x6e\x3a\xf5\xcf\x3e\xd7\xaa\x68\xb1\x91\xfe\xa4" "\x67\x66\xe9\xa1\xb3\xb4\xc9\xb0\x75\xf7\x4c\x98\x1f\x80\x44\x53\x89" "\x8a\x0b\x8f\x9d\x08\x1e\xf6\x43\x7d\x40\x51\xa3\x1e\xef\xf8\x78\x44" "\x21\xe4\x78\xa6\xe0\x4e\x0f\xb3\x69\xef\x95\xf2\x89\xff\x35\xa2\x43" "\x34\xba\x0d\x5a\xc0\x37\x02\x8b\x66\x59\x00\x00\x00\x00\x00\x00\x00" "\x00\x00\x00", 309)); NONFAILING(*(uint64_t*)0x20000248 = 0xb8); NONFAILING(*(uint64_t*)0x20000298 = 1); NONFAILING(*(uint64_t*)0x200002a0 = 0); NONFAILING(*(uint64_t*)0x200002a8 = 0); NONFAILING(*(uint32_t*)0x200002b0 = 0); syscall(__NR_sendmsg, r[0], 0x20000280ul, 0ul); break; case 2: res = syscall(__NR_socket, 0x10ul, 3ul, 0xcul); if (res != -1) r[1] = res; break; case 3: NONFAILING(*(uint64_t*)0x20000500 = 0); NONFAILING(*(uint32_t*)0x20000508 = 0); NONFAILING(*(uint64_t*)0x20000510 = 0x200004c0); NONFAILING(*(uint64_t*)0x200004c0 = 0x20000400); NONFAILING(*(uint32_t*)0x20000400 = 0x14); NONFAILING(*(uint16_t*)0x20000404 = 0x10); NONFAILING(*(uint16_t*)0x20000406 = 1); NONFAILING(*(uint32_t*)0x20000408 = 0); NONFAILING(*(uint32_t*)0x2000040c = 0); NONFAILING(*(uint8_t*)0x20000410 = 0); NONFAILING(*(uint8_t*)0x20000411 = 0); NONFAILING(*(uint16_t*)0x20000412 = htobe16(0xa)); NONFAILING(*(uint32_t*)0x20000414 = 0x70); NONFAILING(*(uint8_t*)0x20000418 = 2); NONFAILING(*(uint8_t*)0x20000419 = 0xa); NONFAILING(*(uint16_t*)0x2000041a = 0xb03); NONFAILING(*(uint32_t*)0x2000041c = 0); NONFAILING(*(uint32_t*)0x20000420 = 0); NONFAILING(*(uint8_t*)0x20000424 = 0); NONFAILING(*(uint8_t*)0x20000425 = 0); NONFAILING(*(uint16_t*)0x20000426 = htobe16(4)); NONFAILING(*(uint16_t*)0x20000428 = 0xc); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000042a, 4, 0, 14)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000042b, 1, 6, 1)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000042b, 0, 7, 1)); NONFAILING(*(uint64_t*)0x2000042c = htobe64(3)); NONFAILING(*(uint16_t*)0x20000434 = 0xc); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000436, 4, 0, 14)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000437, 1, 6, 1)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000437, 0, 7, 1)); NONFAILING(*(uint64_t*)0x20000438 = htobe64(5)); NONFAILING(*(uint16_t*)0x20000440 = 8); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000442, 2, 0, 14)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000443, 1, 6, 1)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000443, 0, 7, 1)); NONFAILING(*(uint32_t*)0x20000444 = htobe32(1)); NONFAILING(*(uint16_t*)0x20000448 = 0xc); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000044a, 4, 0, 14)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000044b, 1, 6, 1)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000044b, 0, 7, 1)); NONFAILING(*(uint64_t*)0x2000044c = htobe64(2)); NONFAILING(*(uint16_t*)0x20000454 = 9); NONFAILING(*(uint16_t*)0x20000456 = 1); NONFAILING(memcpy((void*)0x20000458, "syz0\000", 5)); NONFAILING(*(uint16_t*)0x20000460 = 0xc); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000462, 4, 0, 14)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000463, 1, 6, 1)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x20000463, 0, 7, 1)); NONFAILING(*(uint64_t*)0x20000464 = htobe64(1)); NONFAILING(*(uint16_t*)0x2000046c = 0xc); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000046e, 4, 0, 14)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000046f, 1, 6, 1)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000046f, 0, 7, 1)); NONFAILING(*(uint64_t*)0x20000470 = htobe64(3)); NONFAILING(*(uint16_t*)0x20000478 = 0xc); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000047a, 4, 0, 14)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000047b, 1, 6, 1)); NONFAILING(STORE_BY_BITMASK(uint16_t, , 0x2000047b, 0, 7, 1)); NONFAILING(*(uint64_t*)0x2000047c = htobe64(4)); NONFAILING(*(uint32_t*)0x20000484 = 0x14); NONFAILING(*(uint16_t*)0x20000488 = 0x11); NONFAILING(*(uint16_t*)0x2000048a = 1); NONFAILING(*(uint32_t*)0x2000048c = 0); NONFAILING(*(uint32_t*)0x20000490 = 0); NONFAILING(*(uint8_t*)0x20000494 = 0); NONFAILING(*(uint8_t*)0x20000495 = 0); NONFAILING(*(uint16_t*)0x20000496 = htobe16(0xa)); NONFAILING(*(uint64_t*)0x200004c8 = 0x98); NONFAILING(*(uint64_t*)0x20000518 = 1); NONFAILING(*(uint64_t*)0x20000520 = 0); NONFAILING(*(uint64_t*)0x20000528 = 0); NONFAILING(*(uint32_t*)0x20000530 = 0x810); syscall(__NR_sendmsg, r[1], 0x20000500ul, 0ul); break; } } int main(void) { syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0); setup_binfmt_misc(); install_segv_handler(); use_temporary_dir(); do_sandbox_none(); return 0; }