// https://syzkaller.appspot.com/bug?id=99a60813b9287a6ef4d1583f9208c6584ffde85a // 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; 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_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); 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); } 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, 45); break; } } for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++) sleep_ms(1); } #ifndef __NR_bpf #define __NR_bpf 321 #endif uint64_t r[6] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; void execute_call(int call) { intptr_t res; switch (call) { case 0: res = syscall(__NR_pipe, 0x20000000ul); if (res != -1) { r[0] = *(uint32_t*)0x20000000; r[1] = *(uint32_t*)0x20000004; } break; case 1: res = syscall(__NR_socket, 2ul, 2ul, 0); if (res != -1) r[2] = res; break; case 2: syscall(__NR_close, r[2]); break; case 3: memcpy((void*)0x20000080, "/dev/net/tun\000", 13); res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000080ul, 0x88002ul, 0ul); if (res != -1) r[3] = res; break; case 4: memcpy((void*)0x20000100, "syzkaller1\000\000\000\000\000\000", 16); *(uint16_t*)0x20000110 = 0xa732; syscall(__NR_ioctl, r[3], 0x400454ca, 0x20000100ul); break; case 5: res = syscall(__NR_socket, 0x10ul, 3ul, 0); if (res != -1) r[4] = res; break; case 6: *(uint32_t*)0x20000180 = 6; *(uint32_t*)0x20000184 = 4; *(uint64_t*)0x20000188 = 0x20000200; *(uint8_t*)0x20000200 = 0x18; STORE_BY_BITMASK(uint8_t, , 0x20000201, 2, 0, 4); STORE_BY_BITMASK(uint8_t, , 0x20000201, 0, 4, 4); *(uint16_t*)0x20000202 = 0; *(uint32_t*)0x20000204 = 0; *(uint8_t*)0x20000208 = 0; *(uint8_t*)0x20000209 = 0; *(uint16_t*)0x2000020a = 0; *(uint32_t*)0x2000020c = 0; *(uint8_t*)0x20000210 = 0x85; *(uint8_t*)0x20000211 = 0; *(uint16_t*)0x20000212 = 0; *(uint32_t*)0x20000214 = 0x2c; *(uint8_t*)0x20000218 = 0x95; *(uint8_t*)0x20000219 = 0; *(uint16_t*)0x2000021a = 0; *(uint32_t*)0x2000021c = 0; *(uint64_t*)0x20000190 = 0x200000c0; memcpy((void*)0x200000c0, "GPL\000", 4); *(uint32_t*)0x20000198 = 4; *(uint32_t*)0x2000019c = 0x1000; *(uint64_t*)0x200001a0 = 0x2062b000; *(uint32_t*)0x200001a8 = 0; *(uint32_t*)0x200001ac = 0; *(uint8_t*)0x200001b0 = 0; *(uint8_t*)0x200001b1 = 0; *(uint8_t*)0x200001b2 = 0; *(uint8_t*)0x200001b3 = 0; *(uint8_t*)0x200001b4 = 0; *(uint8_t*)0x200001b5 = 0; *(uint8_t*)0x200001b6 = 0; *(uint8_t*)0x200001b7 = 0; *(uint8_t*)0x200001b8 = 0; *(uint8_t*)0x200001b9 = 0; *(uint8_t*)0x200001ba = 0; *(uint8_t*)0x200001bb = 0; *(uint8_t*)0x200001bc = 0; *(uint8_t*)0x200001bd = 0; *(uint8_t*)0x200001be = 0; *(uint8_t*)0x200001bf = 0; *(uint32_t*)0x200001c0 = 0; *(uint32_t*)0x200001c4 = 0; *(uint32_t*)0x200001c8 = -1; *(uint32_t*)0x200001cc = 8; *(uint64_t*)0x200001d0 = 0; *(uint32_t*)0x200001d8 = 0; *(uint32_t*)0x200001dc = 0x10; *(uint64_t*)0x200001e0 = 0; *(uint32_t*)0x200001e8 = 0; *(uint32_t*)0x200001ec = 0; *(uint32_t*)0x200001f0 = -1; res = syscall(__NR_bpf, 5ul, 0x20000180ul, 0x70ul); if (res != -1) r[5] = res; break; case 7: *(uint64_t*)0x20000140 = 0; *(uint32_t*)0x20000148 = 0x1a0; *(uint64_t*)0x20000150 = 0x20000080; *(uint64_t*)0x20000080 = 0x20000000; *(uint32_t*)0x20000000 = 0x34; *(uint16_t*)0x20000004 = 0x10; *(uint16_t*)0x20000006 = 0x801; *(uint32_t*)0x20000008 = 0; *(uint32_t*)0x2000000c = 0; *(uint8_t*)0x20000010 = 0; *(uint8_t*)0x20000011 = 0; *(uint16_t*)0x20000012 = 0; *(uint32_t*)0x20000014 = 0; *(uint32_t*)0x20000018 = 0; *(uint32_t*)0x2000001c = 0; *(uint16_t*)0x20000020 = 0xc; STORE_BY_BITMASK(uint16_t, , 0x20000022, 0x2b, 0, 14); STORE_BY_BITMASK(uint16_t, , 0x20000023, 0, 6, 1); STORE_BY_BITMASK(uint16_t, , 0x20000023, 1, 7, 1); *(uint16_t*)0x20000024 = 8; *(uint16_t*)0x20000026 = 1; *(uint32_t*)0x20000028 = r[5]; *(uint16_t*)0x2000002c = 8; *(uint16_t*)0x2000002e = 0x1b; *(uint32_t*)0x20000030 = 0; *(uint64_t*)0x20000088 = 0x34; *(uint64_t*)0x20000158 = 1; *(uint64_t*)0x20000160 = 0; *(uint64_t*)0x20000168 = 0; *(uint32_t*)0x20000170 = 0; syscall(__NR_sendmsg, r[4], 0x20000140ul, 0ul); break; case 8: syscall(__NR_write, r[1], 0x20000140ul, 0x1000000c8ul); break; case 9: syscall(__NR_splice, r[0], 0ul, r[2], 0ul, 0x10008ul, 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; }