// https://syzkaller.appspot.com/bug?id=7c7bd742d3b6b7473427759ad255c581dbd94412 // 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 __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 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 MAX_PIDS 32 #define ADDR_MAX_LEN 32 #define LOCAL_MAC "aa:aa:aa:aa:%02hx:aa" #define REMOTE_MAC "aa:aa:aa:aa:%02hx:bb" #define LOCAL_IPV4 "172.20.%d.170" #define REMOTE_IPV4 "172.20.%d.187" #define LOCAL_IPV6 "fe80::%02hx:aa" #define REMOTE_IPV6 "fe80::%02hx:bb" #define IFF_NAPI 0x0010 #define IFF_NAPI_FRAGS 0x0020 static void initialize_tun(int id) { if (id >= MAX_PIDS) fail("tun: no more than %d executors", MAX_PIDS); 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; } char iface[IFNAMSIZ]; snprintf_check(iface, sizeof(iface), "syz%d", id); struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); strncpy(ifr.ifr_name, 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; char local_mac[ADDR_MAX_LEN]; snprintf_check(local_mac, sizeof(local_mac), LOCAL_MAC, id); char remote_mac[ADDR_MAX_LEN]; snprintf_check(remote_mac, sizeof(remote_mac), REMOTE_MAC, id); char local_ipv4[ADDR_MAX_LEN]; snprintf_check(local_ipv4, sizeof(local_ipv4), LOCAL_IPV4, id); char remote_ipv4[ADDR_MAX_LEN]; snprintf_check(remote_ipv4, sizeof(remote_ipv4), REMOTE_IPV4, id); char local_ipv6[ADDR_MAX_LEN]; snprintf_check(local_ipv6, sizeof(local_ipv6), LOCAL_IPV6, id); char remote_ipv6[ADDR_MAX_LEN]; snprintf_check(remote_ipv6, sizeof(remote_ipv6), REMOTE_IPV6, id); execute_command(1, "sysctl -w net.ipv6.conf.%s.accept_dad=0", iface); execute_command(1, "sysctl -w net.ipv6.conf.%s.router_solicitations=0", iface); execute_command(1, "ip link set dev %s address %s", iface, local_mac); execute_command(1, "ip addr add %s/24 dev %s", local_ipv4, iface); execute_command(1, "ip -6 addr add %s/120 dev %s", local_ipv6, iface); execute_command(1, "ip neigh add %s lladdr %s dev %s nud permanent", remote_ipv4, remote_mac, iface); execute_command(1, "ip -6 neigh add %s lladdr %s dev %s nud permanent", remote_ipv6, remote_mac, iface); execute_command(1, "ip link set dev %s up", iface); } #define DEV_IPV4 "172.20.%d.%d" #define DEV_IPV6 "fe80::%02hx:%02hx" #define DEV_MAC "aa:aa:aa:aa:%02hx:%02hx" static void initialize_netdevices(int id) { unsigned i; const char* devtypes[] = {"ip6gretap", "bridge", "vcan"}; const char* devnames[] = {"lo", "sit0", "bridge0", "vcan0", "tunl0", "gre0", "gretap0", "ip_vti0", "ip6_vti0", "ip6tnl0", "ip6gre0", "ip6gretap0", "erspan0"}; for (i = 0; i < sizeof(devtypes) / (sizeof(devtypes[0])); i++) execute_command(0, "ip link add dev %s0 type %s", devtypes[i], devtypes[i]); for (i = 0; i < sizeof(devnames) / (sizeof(devnames[0])); i++) { char addr[ADDR_MAX_LEN]; snprintf_check(addr, sizeof(addr), DEV_IPV4, id, id + 10); execute_command(0, "ip -4 addr add %s/24 dev %s", addr, devnames[i]); snprintf_check(addr, sizeof(addr), DEV_IPV6, id, id + 10); execute_command(0, "ip -6 addr add %s/120 dev %s", addr, devnames[i]); snprintf_check(addr, sizeof(addr), DEV_MAC, id, id + 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 setup_tun(uint64_t pid, bool enable_tun) { if (enable_tun) { initialize_tun(pid); initialize_netdevices(pid); } } #define MAX_FRAGS 4 struct vnet_fragmentation { uint32_t full; uint32_t count; uint32_t frags[MAX_FRAGS]; }; static uintptr_t syz_emit_ethernet(uintptr_t a0, uintptr_t a1, uintptr_t a2) { if (tunfd < 0) return (uintptr_t)-1; uint32_t length = a0; char* data = (char*)a1; struct vnet_fragmentation* frags = (struct vnet_fragmentation*)a2; struct iovec vecs[MAX_FRAGS + 1]; uint32_t nfrags = 0; if (!tun_frags_enabled || frags == NULL) { vecs[nfrags].iov_base = data; vecs[nfrags].iov_len = length; nfrags++; } else { bool full = true; uint32_t i, count = 0; NONFAILING(full = frags->full); NONFAILING(count = frags->count); if (count > MAX_FRAGS) count = MAX_FRAGS; for (i = 0; i < count && length != 0; i++) { uint32_t size = 0; NONFAILING(size = frags->frags[i]); if (size > length) size = length; vecs[nfrags].iov_base = data; vecs[nfrags].iov_len = size; nfrags++; data += size; length -= size; } if (length != 0 && (full || nfrags == 0)) { vecs[nfrags].iov_base = data; vecs[nfrags].iov_len = length; nfrags++; } } return writev(tunfd, vecs, nfrags); } 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 int do_sandbox_none(int executor_pid, bool enable_tun) { if (unshare(CLONE_NEWPID)) { } int pid = fork(); if (pid < 0) fail("sandbox fork failed"); if (pid) return pid; sandbox_common(); if (unshare(CLONE_NEWNET)) { } setup_tun(executor_pid, enable_tun); loop(); doexit(1); } static void test(); void loop() { while (1) { test(); } } 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; } } } } long r[1]; uint64_t procid; void execute_call(int call) { switch (call) { case 0: syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0); break; case 1: r[0] = syscall(__NR_socket, 2, 1, 0); break; case 2: NONFAILING(*(uint32_t*)0x20d06000 = 1); syscall(__NR_setsockopt, r[0], 6, 0x10000000013, 0x20d06000, 4); break; case 3: NONFAILING(*(uint32_t*)0x20788ffc = 1); syscall(__NR_setsockopt, r[0], 6, 0x14, 0x20788ffc, 4); break; case 4: NONFAILING(*(uint16_t*)0x20385ff0 = 2); NONFAILING(*(uint16_t*)0x20385ff2 = 0); NONFAILING(*(uint32_t*)0x20385ff4 = htobe32(0x7f000001)); NONFAILING(*(uint8_t*)0x20385ff8 = 0); NONFAILING(*(uint8_t*)0x20385ff9 = 0); NONFAILING(*(uint8_t*)0x20385ffa = 0); NONFAILING(*(uint8_t*)0x20385ffb = 0); NONFAILING(*(uint8_t*)0x20385ffc = 0); NONFAILING(*(uint8_t*)0x20385ffd = 0); NONFAILING(*(uint8_t*)0x20385ffe = 0); NONFAILING(*(uint8_t*)0x20385fff = 0); syscall(__NR_sendto, r[0], 0x20852000, 0, 0x20020003, 0x20385ff0, 0x10); break; case 5: NONFAILING(*(uint64_t*)0x205c4000 = 0x206f7ff8); NONFAILING(*(uint32_t*)0x205c4008 = 8); NONFAILING(*(uint64_t*)0x205c4010 = 0x2027efb0); NONFAILING(*(uint64_t*)0x205c4018 = 1); NONFAILING(*(uint64_t*)0x205c4020 = 0x201cd000); NONFAILING(*(uint64_t*)0x205c4028 = 0); NONFAILING(*(uint32_t*)0x205c4030 = 0); NONFAILING(*(uint16_t*)0x206f7ff8 = 0x1f); NONFAILING(*(uint8_t*)0x206f7ffa = 0); NONFAILING(*(uint8_t*)0x206f7ffb = 0); NONFAILING(*(uint8_t*)0x206f7ffc = 0); NONFAILING(*(uint8_t*)0x206f7ffd = 0); NONFAILING(*(uint8_t*)0x206f7ffe = 0); NONFAILING(*(uint8_t*)0x206f7fff = 0); NONFAILING(*(uint64_t*)0x2027efb0 = 0x20b82f6c); NONFAILING(*(uint64_t*)0x2027efb8 = 1); NONFAILING(memcpy((void*)0x20b82f6c, "A", 1)); syscall(__NR_sendmsg, r[0], 0x205c4000, 0); break; case 6: NONFAILING(*(uint8_t*)0x20c8d000 = 0xaa); NONFAILING(*(uint8_t*)0x20c8d001 = 0xaa); NONFAILING(*(uint8_t*)0x20c8d002 = 0xaa); NONFAILING(*(uint8_t*)0x20c8d003 = 0xaa); NONFAILING(*(uint8_t*)0x20c8d004 = 0 + procid * 1); NONFAILING(*(uint8_t*)0x20c8d005 = 0xaa); NONFAILING(memcpy((void*)0x20c8d006, "\x6f\x76\x6f\xf6\xd2\xec", 6)); NONFAILING(*(uint16_t*)0x20c8d00c = htobe16(0x11)); NONFAILING(*(uint8_t*)0x20c8d00e = 1); NONFAILING(*(uint8_t*)0x20c8d00f = 0xaa); NONFAILING(memcpy((void*)0x20c8d010, "\xdf", 1)); NONFAILING(memcpy((void*)0x20c8d011, "\xc7\x6d\x49", 3)); NONFAILING(*(uint16_t*)0x20c8d014 = htobe16(0x60)); NONFAILING(*(uint32_t*)0x204dbff4 = 1); NONFAILING(*(uint32_t*)0x204dbff8 = 1); NONFAILING(*(uint32_t*)0x204dbffc = 0x6a4); syz_emit_ethernet(0x16, 0x20c8d000, 0x204dbff4); break; } } void test() { memset(r, -1, sizeof(r)); execute(7); collide = 1; execute(7); } int main() { for (procid = 0; procid < 8; procid++) { if (fork() == 0) { install_segv_handler(); for (;;) { int pid = do_sandbox_none(procid, true); int status = 0; while (waitpid(pid, &status, __WALL) != pid) { } } } } sleep(1000000); return 0; }