// https://syzkaller.appspot.com/bug?id=13abcb2c9eea7e408f8e25d3a9ae401754723024 // 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 __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); } static uint64_t current_time_ms() { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) fail("clock_gettime failed"); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } 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); } } static int read_tun(char* data, int size) { if (tunfd < 0) return -1; int rv = read(tunfd, data, size); if (rv < 0) { if (errno == EAGAIN) return -1; if (errno == EBADFD) return -1; fail("tun: read failed with %d", rv); } return rv; } static void flush_tun() { char data[SYZ_TUN_MAX_PACKET_SIZE]; while (read_tun(&data[0], sizeof(data)) != -1) ; } static void test(); void loop() { int iter; for (iter = 0;; iter++) { int pid = fork(); if (pid < 0) fail("loop fork failed"); if (pid == 0) { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); flush_tun(); test(); doexit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { int res = waitpid(-1, &status, __WALL | WNOHANG); if (res == pid) break; usleep(1000); if (current_time_ms() - start > 5 * 1000) { kill(-pid, SIGKILL); kill(pid, SIGKILL); while (waitpid(-1, &status, __WALL) != pid) { } break; } } } } #ifndef __NR_mmap #define __NR_mmap 192 #endif #ifndef __NR_socket #define __NR_socket 359 #endif #ifndef __NR_bind #define __NR_bind 361 #endif #ifndef __NR_connect #define __NR_connect 362 #endif #undef __NR_mmap #define __NR_mmap __NR_mmap2 long r[2]; void test() { memset(r, -1, sizeof(r)); syscall(__NR_mmap, 0x20000000, 0xe74000, 3, 0x32, -1, 0); r[0] = syscall(__NR_socket, 0xa, 2, 0); r[1] = syscall(__NR_socket, 0x18, 1, 1); *(uint16_t*)0x20e72fe4 = 0xa; *(uint16_t*)0x20e72fe6 = htobe16(0x4e23); *(uint32_t*)0x20e72fe8 = 1; *(uint8_t*)0x20e72fec = 0; *(uint8_t*)0x20e72fed = 0; *(uint8_t*)0x20e72fee = 0; *(uint8_t*)0x20e72fef = 0; *(uint8_t*)0x20e72ff0 = 0; *(uint8_t*)0x20e72ff1 = 0; *(uint8_t*)0x20e72ff2 = 0; *(uint8_t*)0x20e72ff3 = 0; *(uint8_t*)0x20e72ff4 = 0; *(uint8_t*)0x20e72ff5 = 0; *(uint8_t*)0x20e72ff6 = -1; *(uint8_t*)0x20e72ff7 = -1; *(uint8_t*)0x20e72ff8 = 0xac; *(uint8_t*)0x20e72ff9 = 0x14; *(uint8_t*)0x20e72ffa = 0; *(uint8_t*)0x20e72ffb = 0xaa; *(uint32_t*)0x20e72ffc = 3; syscall(__NR_bind, r[0], 0x20e72fe4, 0x1c); *(uint16_t*)0x20e71000 = 0x18; *(uint32_t*)0x20e71002 = 1; *(uint32_t*)0x20e71006 = 0; *(uint32_t*)0x20e7100a = r[0]; *(uint16_t*)0x20e7100e = 3; *(uint16_t*)0x20e71010 = 0; *(uint16_t*)0x20e71012 = 3; *(uint16_t*)0x20e71014 = 0; *(uint16_t*)0x20e71016 = 0xa; *(uint16_t*)0x20e71018 = htobe16(0x4e22); *(uint32_t*)0x20e7101a = 3; *(uint8_t*)0x20e7101e = 0xfe; *(uint8_t*)0x20e7101f = 0x80; *(uint8_t*)0x20e71020 = 0; *(uint8_t*)0x20e71021 = 0; *(uint8_t*)0x20e71022 = 0; *(uint8_t*)0x20e71023 = 0; *(uint8_t*)0x20e71024 = 0; *(uint8_t*)0x20e71025 = 0; *(uint8_t*)0x20e71026 = 0; *(uint8_t*)0x20e71027 = 0; *(uint8_t*)0x20e71028 = 0; *(uint8_t*)0x20e71029 = 0; *(uint8_t*)0x20e7102a = 0; *(uint8_t*)0x20e7102b = 0; *(uint8_t*)0x20e7102c = 0; *(uint8_t*)0x20e7102d = 0xbb; *(uint32_t*)0x20e7102e = 4; syscall(__NR_connect, r[1], 0x20e71000, 0x32); } int main() { for (;;) { setup_tun(0, true); loop(); } }