// https://syzkaller.appspot.com/bug?id=4f5b71612ca24f1c814f1413a8022656c4cae691 // 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 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; \ } struct csum_inet { uint32_t acc; }; static void csum_inet_init(struct csum_inet* csum) { csum->acc = 0; } static void csum_inet_update(struct csum_inet* csum, const uint8_t* data, size_t length) { if (length == 0) return; size_t i; for (i = 0; i < length - 1; i += 2) csum->acc += *(uint16_t*)&data[i]; if (length & 1) csum->acc += (uint16_t)data[length - 1]; while (csum->acc > 0xffff) csum->acc = (csum->acc & 0xffff) + (csum->acc >> 16); } static uint16_t csum_inet_digest(struct csum_inet* csum) { return ~csum->acc; } 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; full = frags->full; count = frags->count; if (count > MAX_FRAGS) count = MAX_FRAGS; for (i = 0; i < count && length != 0; i++) { uint32_t size = 0; 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); } long r[2]; void loop() { memset(r, -1, sizeof(r)); r[0] = syscall(__NR_socket, 0x11, 3, 0x300); *(uint8_t*)0x20f3afd8 = 0x73; *(uint8_t*)0x20f3afd9 = 0x79; *(uint8_t*)0x20f3afda = 0x7a; *(uint8_t*)0x20f3afdb = 0x30; *(uint8_t*)0x20f3afdc = 0; *(uint32_t*)0x20f3afe8 = 0; *(uint8_t*)0x20f3afec = 0; *(uint8_t*)0x20f3afed = 0; *(uint8_t*)0x20f3afee = 0; *(uint8_t*)0x20f3afef = 0; *(uint8_t*)0x20f3aff0 = 0; *(uint8_t*)0x20f3aff1 = 0; *(uint8_t*)0x20f3aff2 = 0; *(uint8_t*)0x20f3aff3 = 0; *(uint8_t*)0x20f3aff4 = 0; *(uint8_t*)0x20f3aff5 = 0; *(uint8_t*)0x20f3aff6 = 0; *(uint8_t*)0x20f3aff7 = 0; *(uint8_t*)0x20f3aff8 = 0; *(uint8_t*)0x20f3aff9 = 0; *(uint8_t*)0x20f3affa = 0; *(uint8_t*)0x20f3affb = 0; *(uint8_t*)0x20f3affc = 0; *(uint8_t*)0x20f3affd = 0; *(uint8_t*)0x20f3affe = 0; *(uint8_t*)0x20f3afff = 0; if (syscall(__NR_ioctl, r[0], 0x8933, 0x20f3afd8) != -1) r[1] = *(uint32_t*)0x20f3afe8; *(uint32_t*)0x2008c000 = 8; syscall(__NR_setsockopt, r[0], 0x107, 0xf, 0x2008c000, 4); memcpy((void*)0x20000000, "\x00\x01\x00\x00\x3e\x02\x00\x14\x00\xf4\x97\x7d\x7b\x41\xb8\xd7\x00" "\x4f\x65\x3b\xcb\x05\x85\x00\x87\xff\xff\xff\xf4\x00\x00\x00\x01\x29" "\xb0\x93\x54\x61\x68\xec\xd9\xca\x02\x0c\x5e\x75\xe2\x27\x06\x2c\x9f" "\x49\x01\x00\x00\x00\x00\x00\x00\x00\xcc\x30\xc4\x00\x80\xff\x37\x8d" "\x58\x08\xd8\xc1\x99\x77\x34\xeb\xc0\xcb\x84\x0b\xf3\xb4\x76\x8a\x94" "\xd1\xed\xdc\x10\x02\x06\x37\x6a\xc4\xc9\x4c\x27\x89\x36\x4e", 100); *(uint16_t*)0x200d9fec = 0x11; *(uint16_t*)0x200d9fee = htobe16(0x800); *(uint32_t*)0x200d9ff0 = r[1]; *(uint16_t*)0x200d9ff4 = 1; *(uint8_t*)0x200d9ff6 = 0; *(uint8_t*)0x200d9ff7 = 6; *(uint8_t*)0x200d9ff8 = 0xaa; *(uint8_t*)0x200d9ff9 = 0xaa; *(uint8_t*)0x200d9ffa = 0xaa; *(uint8_t*)0x200d9ffb = 0xaa; *(uint8_t*)0x200d9ffc = 0; *(uint8_t*)0x200d9ffd = 0; *(uint8_t*)0x200d9ffe = 0; *(uint8_t*)0x200d9fff = 0; syscall(__NR_sendto, r[0], 0x20000000, 0x64, 0, 0x200d9fec, 0x14); memcpy((void*)0x20005faa, "\xcd\x39\x97\x03\x0f\x00", 6); *(uint8_t*)0x20005fb0 = 0; *(uint8_t*)0x20005fb1 = 0; *(uint8_t*)0x20005fb2 = 0; *(uint8_t*)0x20005fb3 = 0; *(uint8_t*)0x20005fb4 = 0; *(uint8_t*)0x20005fb5 = 0; *(uint16_t*)0x20005fb6 = htobe16(0x86dd); STORE_BY_BITMASK(uint8_t, 0x20005fb8, 0, 0, 4); STORE_BY_BITMASK(uint8_t, 0x20005fb8, 6, 4, 4); memcpy((void*)0x20005fb9, "\xc8\xfb\xa2", 3); *(uint16_t*)0x20005fbc = htobe16(0x18); *(uint8_t*)0x20005fbe = 0x3a; *(uint8_t*)0x20005fbf = -1; *(uint8_t*)0x20005fc0 = 0; *(uint8_t*)0x20005fc1 = 0; *(uint8_t*)0x20005fc2 = 0; *(uint8_t*)0x20005fc3 = 0; *(uint8_t*)0x20005fc4 = 0; *(uint8_t*)0x20005fc5 = 0; *(uint8_t*)0x20005fc6 = 0; *(uint8_t*)0x20005fc7 = 0; *(uint8_t*)0x20005fc8 = 0; *(uint8_t*)0x20005fc9 = 0; *(uint8_t*)0x20005fca = 0; *(uint8_t*)0x20005fcb = 0; *(uint8_t*)0x20005fcc = 0; *(uint8_t*)0x20005fcd = 0; *(uint8_t*)0x20005fce = 0; *(uint8_t*)0x20005fcf = 0; *(uint8_t*)0x20005fd0 = -1; *(uint8_t*)0x20005fd1 = 2; *(uint8_t*)0x20005fd2 = 0; *(uint8_t*)0x20005fd3 = 0; *(uint8_t*)0x20005fd4 = 0; *(uint8_t*)0x20005fd5 = 0; *(uint8_t*)0x20005fd6 = 0; *(uint8_t*)0x20005fd7 = 0; *(uint8_t*)0x20005fd8 = 0; *(uint8_t*)0x20005fd9 = 0; *(uint8_t*)0x20005fda = 0; *(uint8_t*)0x20005fdb = 0; *(uint8_t*)0x20005fdc = 0; *(uint8_t*)0x20005fdd = 0; *(uint8_t*)0x20005fde = 0; *(uint8_t*)0x20005fdf = 1; *(uint8_t*)0x20005fe0 = 0x87; *(uint8_t*)0x20005fe1 = 0; *(uint16_t*)0x20005fe2 = 0; *(uint16_t*)0x20005fe4 = htobe16(0); *(uint16_t*)0x20005fe6 = 0; *(uint64_t*)0x20005fe8 = htobe64(0); *(uint64_t*)0x20005ff0 = htobe64(1); struct csum_inet csum_1; csum_inet_init(&csum_1); csum_inet_update(&csum_1, (const uint8_t*)0x20005fc0, 16); csum_inet_update(&csum_1, (const uint8_t*)0x20005fd0, 16); uint32_t csum_1_chunk_2 = 0x18000000; csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_2, 4); uint32_t csum_1_chunk_3 = 0x3a000000; csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_3, 4); csum_inet_update(&csum_1, (const uint8_t*)0x20005fe0, 24); *(uint16_t*)0x20005fe2 = csum_inet_digest(&csum_1); syz_emit_ethernet(0x4e, 0x20005faa, 0); } int main() { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); setup_tun(0, true); loop(); return 0; }