// https://syzkaller.appspot.com/bug?id=95b97b9a7a3c065d463930b72f9f678429eae50f // 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 const int kFailStatus = 67; const int kRetryStatus = 69; __attribute__((noreturn)) static void doexit(int status) { volatile unsigned i; syscall(__NR_exit_group, status); for (i = 0;; i++) { } } __attribute__((noreturn)) static void fail(const char* msg, ...) { int e = errno; fflush(stdout); 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); for (;;) { } } 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 static void execute_command(const char* format, ...) { va_list args; char command[COMMAND_MAX_LEN]; int rv; va_start(args, format); vsnprintf_check(command, sizeof(command), format, args); rv = system(command); if (rv != 0) fail("tun: command \"%s\" failed with code %d", &command[0], rv); va_end(args); } static int tunfd = -1; #define SYZ_TUN_MAX_PACKET_SIZE 1000 #define MAX_PIDS 32 #define ADDR_MAX_LEN 32 #define LOCAL_MAC "aa:aa:aa:aa:aa:%02hx" #define REMOTE_MAC "bb:bb:bb:bb:bb:%02hx" #define LOCAL_IPV4 "172.20.%d.170" #define REMOTE_IPV4 "172.20.%d.187" #define LOCAL_IPV6 "fe80::%02hxaa" #define REMOTE_IPV6 "fe80::%02hxbb" static void initialize_tun(uint64_t pid) { if (pid >= MAX_PIDS) fail("tun: no more than %d executors", MAX_PIDS); int id = pid; tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK); if (tunfd == -1) fail("tun: can't open /dev/net/tun"); 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; if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) fail("tun: ioctl(TUNSETIFF) failed"); 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("sysctl -w net.ipv6.conf.%s.accept_dad=0", iface); execute_command("sysctl -w net.ipv6.conf.%s.router_solicitations=0", iface); execute_command("ip link set dev %s address %s", iface, local_mac); execute_command("ip addr add %s/24 dev %s", local_ipv4, iface); execute_command("ip -6 addr add %s/120 dev %s", local_ipv6, iface); execute_command("ip neigh add %s lladdr %s dev %s nud permanent", remote_ipv4, remote_mac, iface); execute_command("ip -6 neigh add %s lladdr %s dev %s nud permanent", remote_ipv6, remote_mac, iface); execute_command("ip link set dev %s up", iface); } static void setup_tun(uint64_t pid, bool enable_tun) { if (enable_tun) initialize_tun(pid); } long r[49]; void loop() { memset(r, -1, sizeof(r)); r[0] = syscall(__NR_mmap, 0x20000000ul, 0xfff000ul, 0x3ul, 0x32ul, 0xfffffffffffffffful, 0x0ul); r[1] = syscall(__NR_socket, 0xful, 0x3ul, 0x2ul); NONFAILING(memcpy((void*)0x2030bff0, "\x02\x0b\xaf\x01\x02\x00\x00" "\x00\x10\x00\x00\x00\x00\x00" "\x00\x7d", 16)); r[3] = syscall(__NR_write, r[1], 0x2030bff0ul, 0x10ul); r[4] = syscall(__NR_socket, 0xaul, 0x2ul, 0x0ul); NONFAILING(*(uint64_t*)0x20000000 = (uint64_t)0x20005000); NONFAILING(*(uint64_t*)0x20000008 = (uint64_t)0x20002fdc); NONFAILING(*(uint64_t*)0x20000010 = (uint64_t)0x20001ff8); NONFAILING(*(uint64_t*)0x20000018 = (uint64_t)0x20004ff0); NONFAILING(*(uint32_t*)0x20000020 = (uint32_t)0x1); NONFAILING(*(uint32_t*)0x20000024 = (uint32_t)0x0); NONFAILING(*(uint32_t*)0x20000028 = (uint32_t)0x2); NONFAILING(*(uint32_t*)0x2000002c = (uint32_t)0x0); NONFAILING(*(uint32_t*)0x20000030 = (uint32_t)0x0); NONFAILING(*(uint32_t*)0x20000034 = (uint32_t)0x0); NONFAILING(*(uint32_t*)0x20000038 = (uint32_t)0x0); NONFAILING(*(uint32_t*)0x2000003c = (uint32_t)0x0); r[17] = syscall(__NR_ioctl, 0xfffffffffffffffful, 0xc04064a0ul, 0x20000000ul); r[18] = syscall(__NR_setsockopt, r[4], 0x29ul, 0x23ul, 0x20000000ul, 0x264ul); r[19] = syscall(__NR_socket, 0xful, 0x4000000000000003ul, 0x2ul); NONFAILING(*(uint64_t*)0x2023dfc8 = (uint64_t)0x20956ff8); NONFAILING(*(uint32_t*)0x2023dfd0 = (uint32_t)0x8); NONFAILING(*(uint64_t*)0x2023dfd8 = (uint64_t)0x2097e000); NONFAILING(*(uint64_t*)0x2023dfe0 = (uint64_t)0x1); NONFAILING(*(uint64_t*)0x2023dfe8 = (uint64_t)0x206d7000); NONFAILING(*(uint64_t*)0x2023dff0 = (uint64_t)0x5); NONFAILING(*(uint32_t*)0x2023dff8 = (uint32_t)0x0); NONFAILING(*(uint16_t*)0x20956ff8 = (uint16_t)0x0); NONFAILING(*(uint8_t*)0x20956ffa = (uint8_t)0x0); NONFAILING(*(uint32_t*)0x20956ffc = (uint32_t)0x4e20); NONFAILING(*(uint64_t*)0x2097e000 = (uint64_t)0x20254000); NONFAILING(*(uint64_t*)0x2097e008 = (uint64_t)0x10); NONFAILING(memcpy((void*)0x20254000, "\x02\x12\x05\x00\x02\x00\x00" "\x00\x00\x00\xf2\x67\x65\x46" "\xb7\xf5", 16)); NONFAILING(*(uint64_t*)0x206d7000 = (uint64_t)0x10); NONFAILING(*(uint32_t*)0x206d7008 = (uint32_t)0x139); NONFAILING(*(uint32_t*)0x206d700c = (uint32_t)0x2b2b); NONFAILING(*(uint64_t*)0x206d7010 = (uint64_t)0x10); NONFAILING(*(uint32_t*)0x206d7018 = (uint32_t)0x111); NONFAILING(*(uint32_t*)0x206d701c = (uint32_t)0x8); NONFAILING(*(uint64_t*)0x206d7020 = (uint64_t)0x10); NONFAILING(*(uint32_t*)0x206d7028 = (uint32_t)0x11b); NONFAILING(*(uint32_t*)0x206d702c = (uint32_t)0x6); NONFAILING(*(uint64_t*)0x206d7030 = (uint64_t)0x10); NONFAILING(*(uint32_t*)0x206d7038 = (uint32_t)0x13f); NONFAILING(*(uint32_t*)0x206d703c = (uint32_t)0x5); NONFAILING(*(uint64_t*)0x206d7040 = (uint64_t)0x10); NONFAILING(*(uint32_t*)0x206d7048 = (uint32_t)0x109); NONFAILING(*(uint32_t*)0x206d704c = (uint32_t)0x401); r[48] = syscall(__NR_sendmsg, r[19], 0x2023dfc8ul, 0x0ul); } int main() { install_segv_handler(); use_temporary_dir(); setup_tun(0, true); loop(); return 0; }