// https://syzkaller.appspot.com/bug?id=4c9c1b7813a6d4531a2782a893874061affc24bb // 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 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 { 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_ACQUIRE)) 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; } 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); 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 (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) { } 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); } static 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); } 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 < 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, 50); break; } } for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++) sleep_ms(1); } uint64_t r[4] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; void execute_call(int call) { intptr_t res = 0; switch (call) { case 0: *(uint64_t*)0x20000180 = 0; *(uint32_t*)0x20000188 = 0; *(uint64_t*)0x20000190 = 0x20000000; *(uint64_t*)0x20000000 = 0; *(uint64_t*)0x20000008 = 0; *(uint64_t*)0x20000198 = 1; *(uint64_t*)0x200001a0 = 0; *(uint64_t*)0x200001a8 = 0; *(uint32_t*)0x200001b0 = 0; syscall(__NR_sendmsg, -1, 0x20000180ul, 0ul); break; case 1: *(uint64_t*)0x20000040 = 0; *(uint32_t*)0x20000048 = 0; *(uint64_t*)0x20000050 = 0x20000000; *(uint64_t*)0x20000000 = 0x20000400; memcpy((void*)0x20000400, "\x34\x01\x00\x00\x10\x00\x05\x17\x00\x7b\x05\x4a\x3a\x00\x00\x03" "\x09\x06\x00\x00", 20); *(uint32_t*)0x20000414 = -1; memcpy( (void*)0x20000418, "\x00\x00\x00\x00\x04\x00\x00\x00\x08\x01\x12\x00\x29\x00\x01\x00\x6d" "\x61\x63\x76\x6c\x61\x6e\x00\xf8\x00\x02\x00\x4c\x00\x05\x00\x0a\x00" "\x04\xff\x00\x00\x00\xca\x64\x63\x04\x92\x2a\x00\x04\x00\xd2\x1b\xf5" "\x46\x05\x00\x00\x00\x00\x00\x00\x01\xea\x9c\x2f\x85\x34\x0b\x00\x00" "\x0a\x10\x04\x00\xaa\xaa\xaa\xaa\xaa\xaa\x00\x00\x7f\xff\x04\x00\xaa" "\xaa\xaa\xaa\xaa\xbb\x20\x00\x0a\x00\x04\x00\xaa\xaa\xaa\xaa\xaa\xbb" "\x00\x00\x0a\x00\x04\x00\xaa\xaa\xaa\xaa\xaa\xbb\x00\x06\x00\x00\x01" "\x00\x10\x00\x00\x00\x0a\x00\x04\x00\xaa\xaa\xaa\x8a\xaa\xaa\x00\x00" "\x0a\x00\x04\x00\xaa\xaa\xaa\xaa\xaa\x23\x00\x00\x08\x00\x03\x00\x03" "\x00\x00\x00\x08\xea\x02\x00\x02\x00\x00\x05\x00\x00\x05\x00\x0a\x19" "\x04\x00\x01\x80\xc2\x00\x00\x03\x00\x00\x0a\x00\x04\x00\xff\xff\xff" "\xff\xff\xff\x00\x00\x0a\x00\x04\x00\xaa\xaa\xaa\xaa\xaa\x24\x00\x00" "\x0a\x00\x04\x00\xff\xff\xff\xff\xff\xff\x00\x00\x0a\x00\x04\x00\x00" "\x00\x00\xff\xff\xff\xff\xff\x09\x00\x04\x00\x00\x00\x00\x00\x00\x00" "\x00\x00\x0a\x00\x04\x00\x01\x80\xc2\x00\x00\x02\x00\x00\x0a\x00\x04" "\x00\x10\xc7\x84\x01\x15\x64\x00\x00\x08\x00\x03\x00\x00\x00\x00\x00" "\x0a\x00\x05\x00\x04", 277); *(uint64_t*)0x20000008 = 0x134; *(uint64_t*)0x20000058 = 1; *(uint64_t*)0x20000060 = 0; *(uint64_t*)0x20000068 = 0; *(uint32_t*)0x20000070 = 0; syscall(__NR_sendmsg, -1, 0x20000040ul, 0ul); break; case 2: res = syscall(__NR_socket, 0x10ul, 3ul, 0); if (res != -1) r[0] = res; break; case 3: syscall(__NR_sendmmsg, r[0], 0x200000c0ul, 0x492492492492627ul, 0ul); break; case 4: res = syscall(__NR_pipe, 0x20000080ul); if (res != -1) { r[1] = *(uint32_t*)0x20000080; r[2] = *(uint32_t*)0x20000084; } break; case 5: res = syscall(__NR_socket, 0x10ul, 3ul, 0); if (res != -1) r[3] = res; break; case 6: *(uint64_t*)0x200000c0 = 0; *(uint32_t*)0x200000c8 = 0; *(uint64_t*)0x200000d0 = 0x20000200; *(uint64_t*)0x20000200 = 0x20000000; memcpy((void*)0x20000000, "\x48\x00\x00\x00\x10\x00\x1f\xff\x00\x00\x05\x00\x00\x40\x00\x00" "\x00\x00\x00\x00", 20); *(uint32_t*)0x20000014 = -1; memcpy((void*)0x20000018, "\x1f\x00\x00\x00\x00\x42\x18\x00\x28\x00\x12\x80\x0a\x00\x01\x00" "\x76\x78\x6c\x61\x6e\x00\x00\x00\x18\x00\x02\x80\x14\x00\x10", 31); *(uint64_t*)0x20000208 = 3; *(uint64_t*)0x200000d8 = 1; *(uint64_t*)0x200000e0 = 0; *(uint64_t*)0x200000e8 = 0; *(uint32_t*)0x200000f0 = 0; syscall(__NR_sendmsg, -1, 0x200000c0ul, 0ul); break; case 7: memcpy((void*)0x20000040, "/dev/hwrng\000", 11); syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000040ul, 0x8800ul, 0ul); break; case 8: syscall(__NR_write, r[2], 0x20000000ul, 0xfffffeccul); break; case 9: syscall(__NR_splice, r[1], 0ul, r[3], 0ul, 0x4fff1ul, 0ul); break; } } int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); do_sandbox_none(); return 0; }