// https://syzkaller.appspot.com/bug?id=556e390bf27cfe4ab863fa16072c21c1a0d19227 // 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 #include #include #include #include #include #include #include #include #include #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 #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); } #define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1) #define BITMASK_LEN_OFF(type, bf_off, bf_len) \ (type)(BITMASK_LEN(type, (bf_len)) << (bf_off)) #define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len) \ if ((bf_off) == 0 && (bf_len) == 0) { \ *(type*)(addr) = (type)(val); \ } else { \ type new_val = *(type*)(addr); \ new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len)); \ new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off); \ *(type*)(addr) = new_val; \ } 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 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 void vsnprintf_check(char* str, size_t size, const char* format, va_list args) { int rv; rv = vsnprintf(str, size, format, args); if (rv < 0) fail("tun: snprintf failed"); if ((size_t)rv >= size) fail("tun: string '%s...' doesn't fit into buffer", str); } static void snprintf_check(char* str, size_t size, const char* format, ...) { va_list args; va_start(args, format); vsnprintf_check(str, size, format, args); va_end(args); } #define COMMAND_MAX_LEN 128 #define PATH_PREFIX \ "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin " #define PATH_PREFIX_LEN (sizeof(PATH_PREFIX) - 1) static void execute_command(bool panic, const char* format, ...) { va_list args; char command[PATH_PREFIX_LEN + COMMAND_MAX_LEN]; int rv; va_start(args, format); memcpy(command, PATH_PREFIX, PATH_PREFIX_LEN); vsnprintf_check(command + PATH_PREFIX_LEN, COMMAND_MAX_LEN, format, args); rv = system(command); if (panic && rv != 0) fail("tun: command \"%s\" failed with code %d", &command[0], rv); va_end(args); } static int tunfd = -1; static int tun_frags_enabled; #define SYZ_TUN_MAX_PACKET_SIZE 1000 #define TUN_IFACE "syz_tun" #define LOCAL_MAC "aa:aa:aa:aa:aa:aa" #define REMOTE_MAC "aa:aa:aa:aa:aa:bb" #define LOCAL_IPV4 "172.20.20.170" #define REMOTE_IPV4 "172.20.20.187" #define LOCAL_IPV6 "fe80::aa" #define REMOTE_IPV6 "fe80::bb" #define IFF_NAPI 0x0010 #define IFF_NAPI_FRAGS 0x0020 static void initialize_tun(void) { tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK); if (tunfd == -1) { printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n"); printf("otherwise fuzzing or reproducing might not work as intended\n"); return; } const int kTunFd = 252; if (dup2(tunfd, kTunFd) < 0) fail("dup2(tunfd, kTunFd) failed"); close(tunfd); tunfd = kTunFd; struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); strncpy(ifr.ifr_name, TUN_IFACE, IFNAMSIZ); ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_NAPI | IFF_NAPI_FRAGS; if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) { ifr.ifr_flags = IFF_TAP | IFF_NO_PI; if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) fail("tun: ioctl(TUNSETIFF) failed"); } if (ioctl(tunfd, TUNGETIFF, (void*)&ifr) < 0) fail("tun: ioctl(TUNGETIFF) failed"); tun_frags_enabled = (ifr.ifr_flags & IFF_NAPI_FRAGS) != 0; execute_command(1, "sysctl -w net.ipv6.conf.%s.accept_dad=0", TUN_IFACE); execute_command(1, "sysctl -w net.ipv6.conf.%s.router_solicitations=0", TUN_IFACE); execute_command(1, "ip link set dev %s address %s", TUN_IFACE, LOCAL_MAC); execute_command(1, "ip addr add %s/24 dev %s", LOCAL_IPV4, TUN_IFACE); execute_command(1, "ip -6 addr add %s/120 dev %s", LOCAL_IPV6, TUN_IFACE); execute_command(1, "ip neigh add %s lladdr %s dev %s nud permanent", REMOTE_IPV4, REMOTE_MAC, TUN_IFACE); execute_command(1, "ip -6 neigh add %s lladdr %s dev %s nud permanent", REMOTE_IPV6, REMOTE_MAC, TUN_IFACE); execute_command(1, "ip link set dev %s up", TUN_IFACE); } #define DEV_IPV4 "172.20.20.%d" #define DEV_IPV6 "fe80::%02hx" #define DEV_MAC "aa:aa:aa:aa:aa:%02hx" static void initialize_netdevices(void) { unsigned i; const char* devtypes[] = {"ip6gretap", "bridge", "vcan", "bond", "veth"}; const char* devnames[] = {"lo", "sit0", "bridge0", "vcan0", "tunl0", "gre0", "gretap0", "ip_vti0", "ip6_vti0", "ip6tnl0", "ip6gre0", "ip6gretap0", "erspan0", "bond0", "veth0", "veth1"}; for (i = 0; i < sizeof(devtypes) / (sizeof(devtypes[0])); i++) execute_command(0, "ip link add dev %s0 type %s", devtypes[i], devtypes[i]); execute_command(0, "ip link add dev veth1 type veth"); for (i = 0; i < sizeof(devnames) / (sizeof(devnames[0])); i++) { char addr[32]; snprintf_check(addr, sizeof(addr), DEV_IPV4, i + 10); execute_command(0, "ip -4 addr add %s/24 dev %s", addr, devnames[i]); snprintf_check(addr, sizeof(addr), DEV_IPV6, i + 10); execute_command(0, "ip -6 addr add %s/120 dev %s", addr, devnames[i]); snprintf_check(addr, sizeof(addr), DEV_MAC, i + 10); execute_command(0, "ip link set dev %s address %s", devnames[i], addr); execute_command(0, "ip link set dev %s up", devnames[i]); } } 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 = 128 << 20; setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 8 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 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); #define CLONE_NEWCGROUP 0x02000000 if (unshare(CLONE_NEWNS)) { } if (unshare(CLONE_NEWIPC)) { } if (unshare(CLONE_NEWCGROUP)) { } if (unshare(CLONE_NEWUTS)) { } if (unshare(CLONE_SYSVSEM)) { } } 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) { close(fd); return false; } close(fd); return true; } static int real_uid; static int real_gid; __attribute__((aligned(64 << 10))) static char sandbox_stack[1 << 20]; static int namespace_sandbox_proc(void* arg) { sandbox_common(); write_file("/proc/self/setgroups", "deny"); if (!write_file("/proc/self/uid_map", "0 %d 1\n", real_uid)) fail("write of /proc/self/uid_map failed"); if (!write_file("/proc/self/gid_map", "0 %d 1\n", real_gid)) fail("write of /proc/self/gid_map failed"); if (unshare(CLONE_NEWNET)) fail("unshare(CLONE_NEWNET)"); initialize_tun(); initialize_netdevices(); if (mkdir("./syz-tmp", 0777)) fail("mkdir(syz-tmp) failed"); if (mount("", "./syz-tmp", "tmpfs", 0, NULL)) fail("mount(tmpfs) failed"); if (mkdir("./syz-tmp/newroot", 0777)) fail("mkdir failed"); if (mkdir("./syz-tmp/newroot/dev", 0700)) fail("mkdir failed"); unsigned mount_flags = MS_BIND | MS_REC | MS_PRIVATE; if (mount("/dev", "./syz-tmp/newroot/dev", NULL, mount_flags, NULL)) fail("mount(dev) failed"); if (mkdir("./syz-tmp/newroot/proc", 0700)) fail("mkdir failed"); if (mount(NULL, "./syz-tmp/newroot/proc", "proc", 0, NULL)) fail("mount(proc) failed"); if (mkdir("./syz-tmp/newroot/selinux", 0700)) fail("mkdir failed"); const char* selinux_path = "./syz-tmp/newroot/selinux"; if (mount("/selinux", selinux_path, NULL, mount_flags, NULL)) { if (errno != ENOENT) fail("mount(/selinux) failed"); if (mount("/sys/fs/selinux", selinux_path, NULL, mount_flags, NULL) && errno != ENOENT) fail("mount(/sys/fs/selinux) failed"); } if (mkdir("./syz-tmp/pivot", 0777)) fail("mkdir failed"); if (syscall(SYS_pivot_root, "./syz-tmp", "./syz-tmp/pivot")) { if (chdir("./syz-tmp")) fail("chdir failed"); } else { if (chdir("/")) fail("chdir failed"); if (umount2("./pivot", MNT_DETACH)) fail("umount failed"); } if (chroot("./newroot")) fail("chroot failed"); if (chdir("/")) fail("chdir failed"); 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)) fail("capget failed"); cap_data[0].effective &= ~(1 << CAP_SYS_PTRACE); cap_data[0].permitted &= ~(1 << CAP_SYS_PTRACE); cap_data[0].inheritable &= ~(1 << CAP_SYS_PTRACE); if (syscall(SYS_capset, &cap_hdr, &cap_data)) fail("capset failed"); loop(); doexit(1); } static int do_sandbox_namespace(void) { int pid; real_uid = getuid(); real_gid = getgid(); mprotect(sandbox_stack, 4096, PROT_NONE); pid = clone(namespace_sandbox_proc, &sandbox_stack[sizeof(sandbox_stack) - 64], CLONE_NEWUSER | CLONE_NEWPID, 0); if (pid < 0) fail("sandbox clone failed"); return pid; } 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; } } } } uint64_t r[2] = {0xffffffffffffffff, 0xffffffff}; void execute_call(int call) { long res; switch (call) { case 0: NONFAILING(memcpy((void*)0x20000140, "/dev/infiniband/rdma_cm", 24)); res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20000140, 2, 0); if (res != -1) r[0] = res; break; case 1: NONFAILING(*(uint32_t*)0x2025c000 = 2); NONFAILING(*(uint32_t*)0x2025c004 = 0x78); NONFAILING(*(uint8_t*)0x2025c008 = 0xe3); NONFAILING(*(uint8_t*)0x2025c009 = 0); NONFAILING(*(uint8_t*)0x2025c00a = 0); NONFAILING(*(uint8_t*)0x2025c00b = 0); NONFAILING(*(uint32_t*)0x2025c00c = 0); NONFAILING(*(uint64_t*)0x2025c010 = 0); NONFAILING(*(uint64_t*)0x2025c018 = 0); NONFAILING(*(uint64_t*)0x2025c020 = 0); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 0, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 1, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 2, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 3, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 4, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0x10000003, 5, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 6, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 7, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 8, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 9, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 10, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 11, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 12, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 13, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 14, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 15, 2)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 17, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 18, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 19, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 20, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 21, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 22, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 23, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 24, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 25, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 26, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 27, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 28, 1)); NONFAILING(STORE_BY_BITMASK(uint64_t, 0x2025c028, 0, 29, 35)); NONFAILING(*(uint32_t*)0x2025c030 = 0); NONFAILING(*(uint32_t*)0x2025c034 = 0); NONFAILING(*(uint64_t*)0x2025c038 = 0x2031f000); NONFAILING(*(uint64_t*)0x2025c040 = 0); NONFAILING(*(uint64_t*)0x2025c048 = 0); NONFAILING(*(uint64_t*)0x2025c050 = 0); NONFAILING(*(uint32_t*)0x2025c058 = 0); NONFAILING(*(uint32_t*)0x2025c05c = 0); NONFAILING(*(uint64_t*)0x2025c060 = 0); NONFAILING(*(uint32_t*)0x2025c068 = 0); NONFAILING(*(uint16_t*)0x2025c06c = 0); NONFAILING(*(uint16_t*)0x2025c06e = 0); syscall(__NR_perf_event_open, 0x2025c000, 0, 0, -1, 0); break; case 2: NONFAILING(memcpy((void*)0x20000000, "/selinux/avc/cache_stats", 25)); syscall(__NR_openat, 0xffffffffffffff9c, 0x20000000, 0, 0); break; case 3: NONFAILING(*(uint32_t*)0x200000c0 = 0); NONFAILING(*(uint16_t*)0x200000c4 = 0x18); NONFAILING(*(uint16_t*)0x200000c6 = 0xfa00); NONFAILING(*(uint64_t*)0x200000c8 = 0); NONFAILING(*(uint64_t*)0x200000d0 = 0x20000080); NONFAILING(*(uint16_t*)0x200000d8 = 2); NONFAILING(*(uint8_t*)0x200000da = 0); NONFAILING(*(uint8_t*)0x200000db = 0); NONFAILING(*(uint8_t*)0x200000dc = 0); NONFAILING(*(uint8_t*)0x200000dd = 0); NONFAILING(*(uint8_t*)0x200000de = 0); NONFAILING(*(uint8_t*)0x200000df = 0); res = syscall(__NR_write, r[0], 0x200000c0, 0xfffffe84); if (res != -1) NONFAILING(r[1] = *(uint32_t*)0x20000080); break; case 4: NONFAILING(*(uint32_t*)0x200003c0 = 1); NONFAILING(*(uint16_t*)0x200003c4 = 0); NONFAILING(*(uint16_t*)0x200003c6 = 0xfa00); NONFAILING(*(uint64_t*)0x200003c8 = 0x20000380); NONFAILING(*(uint32_t*)0x200003d0 = r[1]); NONFAILING(*(uint32_t*)0x200003d4 = 0); syscall(__NR_write, r[0], 0x200003c0, 0x314); break; } } void loop() { execute(5); collide = 1; execute(5); } int main() { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); install_segv_handler(); use_temporary_dir(); int pid = do_sandbox_namespace(); int status = 0; while (waitpid(pid, &status, __WALL) != pid) { } return 0; }