// https://syzkaller.appspot.com/bug?id=8af2597890938b642c3bf44a85859691fb9d5cfa // 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 __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); } 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]); } } #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); } uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff}; void loop() { long res; res = syscall(__NR_socket, 0xa, 2, 0); if (res != -1) r[0] = res; res = syscall(__NR_socket, 0x18, 1, 1); if (res != -1) r[1] = res; NONFAILING(*(uint16_t*)0x205fafd2 = 0x18); NONFAILING(*(uint32_t*)0x205fafd4 = 1); NONFAILING(*(uint32_t*)0x205fafd8 = 0); NONFAILING(*(uint32_t*)0x205fafdc = r[0]); NONFAILING(*(uint16_t*)0x205fafe0 = 2); NONFAILING(*(uint16_t*)0x205fafe2 = htobe16(0x4e21)); NONFAILING(*(uint8_t*)0x205fafe4 = 0xac); NONFAILING(*(uint8_t*)0x205fafe5 = 0x14); NONFAILING(*(uint8_t*)0x205fafe6 = 0); NONFAILING(*(uint8_t*)0x205fafe7 = 0xbb); NONFAILING(*(uint8_t*)0x205fafe8 = 0); NONFAILING(*(uint8_t*)0x205fafe9 = 0); NONFAILING(*(uint8_t*)0x205fafea = 0); NONFAILING(*(uint8_t*)0x205fafeb = 0); NONFAILING(*(uint8_t*)0x205fafec = 0); NONFAILING(*(uint8_t*)0x205fafed = 0); NONFAILING(*(uint8_t*)0x205fafee = 0); NONFAILING(*(uint8_t*)0x205fafef = 0); NONFAILING(*(uint32_t*)0x205faff0 = 4); NONFAILING(*(uint32_t*)0x205faff4 = 0); NONFAILING(*(uint32_t*)0x205faff8 = 2); NONFAILING(*(uint32_t*)0x205faffc = 0); syscall(__NR_connect, r[1], 0x205fafd2, 0x2e); NONFAILING(*(uint16_t*)0x200000c0 = 0xa); NONFAILING(*(uint16_t*)0x200000c2 = htobe16(0x4e21)); NONFAILING(*(uint32_t*)0x200000c4 = 0x7fff); NONFAILING(*(uint8_t*)0x200000c8 = 0); NONFAILING(*(uint8_t*)0x200000c9 = 0); NONFAILING(*(uint8_t*)0x200000ca = 0); NONFAILING(*(uint8_t*)0x200000cb = 0); NONFAILING(*(uint8_t*)0x200000cc = 0); NONFAILING(*(uint8_t*)0x200000cd = 0); NONFAILING(*(uint8_t*)0x200000ce = 0); NONFAILING(*(uint8_t*)0x200000cf = 0); NONFAILING(*(uint8_t*)0x200000d0 = 0); NONFAILING(*(uint8_t*)0x200000d1 = 0); NONFAILING(*(uint8_t*)0x200000d2 = -1); NONFAILING(*(uint8_t*)0x200000d3 = -1); NONFAILING(*(uint8_t*)0x200000d4 = 0xac); NONFAILING(*(uint8_t*)0x200000d5 = 0x14); NONFAILING(*(uint8_t*)0x200000d6 = 0x14); NONFAILING(*(uint8_t*)0x200000d7 = 0xaa); NONFAILING(*(uint32_t*)0x200000d8 = 3); syscall(__NR_connect, r[0], 0x200000c0, 0x1c); NONFAILING(*(uint16_t*)0x200021c0 = 0x18); NONFAILING(*(uint32_t*)0x200021c2 = 0); NONFAILING(*(uint16_t*)0x200021c6 = 0); NONFAILING(*(uint8_t*)0x200021c8 = 0); NONFAILING(*(uint8_t*)0x200021c9 = 0); NONFAILING(*(uint8_t*)0x200021ca = 0); NONFAILING(*(uint8_t*)0x200021cb = 0); NONFAILING(*(uint8_t*)0x200021cc = 0); NONFAILING(*(uint8_t*)0x200021cd = 0); NONFAILING(memcpy( (void*)0x200021ce, "\x69\x66\x62\x30\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)); syscall(__NR_sendto, r[1], 0x20001180, 0, 0x40001, 0x200021c0, 0x80); NONFAILING(*(uint32_t*)0x20001780 = 0); NONFAILING(*(uint32_t*)0x20001784 = 0); NONFAILING(*(uint32_t*)0x20001788 = 0); NONFAILING(*(uint32_t*)0x2000178c = 0); NONFAILING(*(uint32_t*)0x20001790 = 0); NONFAILING(*(uint32_t*)0x20001794 = 0); syz_emit_ethernet(1, 0x20000700, 0x20001780); } int main() { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); install_segv_handler(); use_temporary_dir(); initialize_tun(); initialize_netdevices(); loop(); return 0; }