// https://syzkaller.appspot.com/bug?id=84909969606053c6256d4b0541443dab936c198d // 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; \ } 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); } #ifndef __NR_mmap #define __NR_mmap 192 #endif #ifndef __NR_socket #define __NR_socket 359 #endif #ifndef __NR_sendmsg #define __NR_sendmsg 370 #endif #undef __NR_mmap #define __NR_mmap __NR_mmap2 long r[1]; void loop() { memset(r, -1, sizeof(r)); syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0); r[0] = syscall(__NR_socket, 0x10, 2, 0); *(uint32_t*)0x20504000 = 0x20dfeff4; *(uint32_t*)0x20504004 = 0xc; *(uint32_t*)0x20504008 = 0x20986000; *(uint32_t*)0x2050400c = 1; *(uint32_t*)0x20504010 = 0; *(uint32_t*)0x20504014 = 0; *(uint32_t*)0x20504018 = 0; *(uint16_t*)0x20dfeff4 = 0x10; *(uint16_t*)0x20dfeff6 = 0; *(uint32_t*)0x20dfeff8 = 0; *(uint32_t*)0x20dfeffc = 0; *(uint32_t*)0x20986000 = 0x200c4f74; *(uint32_t*)0x20986004 = 0x3c; *(uint32_t*)0x200c4f74 = 0x3c; *(uint16_t*)0x200c4f78 = 0x10; *(uint16_t*)0x200c4f7a = 9; *(uint32_t*)0x200c4f7c = 0; *(uint32_t*)0x200c4f80 = 0; *(uint8_t*)0x200c4f84 = 0; *(uint8_t*)0x200c4f85 = 0; *(uint16_t*)0x200c4f86 = 0; *(uint32_t*)0x200c4f88 = 0; *(uint32_t*)0x200c4f8c = 0; *(uint32_t*)0x200c4f90 = 0; *(uint16_t*)0x200c4f94 = 0x14; *(uint16_t*)0x200c4f96 = 3; *(uint8_t*)0x200c4f98 = 0x73; *(uint8_t*)0x200c4f99 = 0x79; *(uint8_t*)0x200c4f9a = 0x7a; *(uint8_t*)0x200c4f9b = 0x30; *(uint8_t*)0x200c4f9c = 0; *(uint16_t*)0x200c4fa8 = 8; *(uint16_t*)0x200c4faa = 0xd; *(uint32_t*)0x200c4fac = 0x80000001; syscall(__NR_sendmsg, r[0], 0x20504000, 0); *(uint8_t*)0x20003f3d = 0; *(uint8_t*)0x20003f3e = 0; *(uint8_t*)0x20003f3f = 0; *(uint8_t*)0x20003f40 = 0; *(uint8_t*)0x20003f41 = 0; *(uint8_t*)0x20003f42 = 0; *(uint8_t*)0x20003f43 = 1; *(uint8_t*)0x20003f44 = 0x80; *(uint8_t*)0x20003f45 = 0xc2; *(uint8_t*)0x20003f46 = 0; *(uint8_t*)0x20003f47 = 0; *(uint8_t*)0x20003f48 = 3; *(uint16_t*)0x20003f49 = htobe16(0x9100); STORE_BY_BITMASK(uint16_t, 0x20003f4b, 5, 0, 3); STORE_BY_BITMASK(uint16_t, 0x20003f4b, 8, 3, 1); STORE_BY_BITMASK(uint16_t, 0x20003f4b, 0x3ff, 4, 12); *(uint16_t*)0x20003f4d = htobe16(0x8100); STORE_BY_BITMASK(uint16_t, 0x20003f4f, 9, 0, 3); STORE_BY_BITMASK(uint16_t, 0x20003f4f, 0, 3, 1); STORE_BY_BITMASK(uint16_t, 0x20003f4f, 0xfffb, 4, 12); *(uint16_t*)0x20003f51 = htobe16(0x8848); STORE_BY_BITMASK(uint32_t, 0x20003f53, htobe32(9), 0, 8); STORE_BY_BITMASK(uint32_t, 0x20003f53, htobe32(0), 8, 1); STORE_BY_BITMASK(uint32_t, 0x20003f53, htobe32(2), 9, 3); STORE_BY_BITMASK(uint32_t, 0x20003f53, htobe32(1), 12, 20); STORE_BY_BITMASK(uint32_t, 0x20003f57, htobe32(0x7fffffff), 0, 8); STORE_BY_BITMASK(uint32_t, 0x20003f57, htobe32(4), 8, 1); STORE_BY_BITMASK(uint32_t, 0x20003f57, htobe32(0), 9, 3); STORE_BY_BITMASK(uint32_t, 0x20003f57, htobe32(0), 12, 20); STORE_BY_BITMASK(uint32_t, 0x20003f5b, htobe32(0x3f), 0, 8); STORE_BY_BITMASK(uint32_t, 0x20003f5b, htobe32(0xd2), 8, 1); STORE_BY_BITMASK(uint32_t, 0x20003f5b, htobe32(9), 9, 3); STORE_BY_BITMASK(uint32_t, 0x20003f5b, htobe32(0), 12, 20); *(uint8_t*)0x20003f5f = 1; *(uint8_t*)0x20003f60 = 0xaa; memcpy((void*)0x20003f61, "*", 1); memcpy((void*)0x20003f62, "\xed\x8b\x9c", 3); *(uint16_t*)0x20003f65 = htobe16(0); *(uint32_t*)0x20001fec = 0; *(uint32_t*)0x20001ff0 = 3; *(uint32_t*)0x20001ff4 = 0x77b; *(uint32_t*)0x20001ff8 = 0x8cc; *(uint32_t*)0x20001ffc = 0x591; syz_emit_ethernet(0x2a, 0x20003f3d, 0x20001fec); } int main() { setup_tun(0, true); loop(); return 0; }