// 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 #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 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 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]); } } 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; } struct ipv6hdr { __u8 priority : 4, version : 4; __u8 flow_lbl[3]; __be16 payload_len; __u8 nexthdr; __u8 hop_limit; struct in6_addr saddr; struct in6_addr daddr; }; struct tcp_resources { uint32_t seq; uint32_t ack; }; static uintptr_t syz_extract_tcp_res(uintptr_t a0, uintptr_t a1, uintptr_t a2) { if (tunfd < 0) return (uintptr_t)-1; char data[SYZ_TUN_MAX_PACKET_SIZE]; int rv = read_tun(&data[0], sizeof(data)); if (rv == -1) return (uintptr_t)-1; size_t length = rv; struct tcphdr* tcphdr; if (length < sizeof(struct ethhdr)) return (uintptr_t)-1; struct ethhdr* ethhdr = (struct ethhdr*)&data[0]; if (ethhdr->h_proto == htons(ETH_P_IP)) { if (length < sizeof(struct ethhdr) + sizeof(struct iphdr)) return (uintptr_t)-1; struct iphdr* iphdr = (struct iphdr*)&data[sizeof(struct ethhdr)]; if (iphdr->protocol != IPPROTO_TCP) return (uintptr_t)-1; if (length < sizeof(struct ethhdr) + iphdr->ihl * 4 + sizeof(struct tcphdr)) return (uintptr_t)-1; tcphdr = (struct tcphdr*)&data[sizeof(struct ethhdr) + iphdr->ihl * 4]; } else { if (length < sizeof(struct ethhdr) + sizeof(struct ipv6hdr)) return (uintptr_t)-1; struct ipv6hdr* ipv6hdr = (struct ipv6hdr*)&data[sizeof(struct ethhdr)]; if (ipv6hdr->nexthdr != IPPROTO_TCP) return (uintptr_t)-1; if (length < sizeof(struct ethhdr) + sizeof(struct ipv6hdr) + sizeof(struct tcphdr)) return (uintptr_t)-1; tcphdr = (struct tcphdr*)&data[sizeof(struct ethhdr) + sizeof(struct ipv6hdr)]; } struct tcp_resources* res = (struct tcp_resources*)a0; res->seq = htonl((ntohl(tcphdr->seq) + (uint32_t)a1)); res->ack = htonl((ntohl(tcphdr->ack_seq) + (uint32_t)a2)); return 0; } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); setsid(); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = 128 << 20; setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 8 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_FSIZE, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_STACK, &rlim); rlim.rlim_cur = rlim.rlim_max = 0; setrlimit(RLIMIT_CORE, &rlim); #define CLONE_NEWCGROUP 0x02000000 if (unshare(CLONE_NEWNS)) { } if (unshare(CLONE_NEWIPC)) { } if (unshare(CLONE_NEWCGROUP)) { } if (unshare(CLONE_NEWUTS)) { } if (unshare(CLONE_SYSVSEM)) { } } static int do_sandbox_none(void) { if (unshare(CLONE_NEWPID)) { } int pid = fork(); if (pid < 0) fail("sandbox fork failed"); if (pid) return pid; sandbox_common(); if (unshare(CLONE_NEWNET)) { } initialize_tun(); initialize_netdevices(); loop(); doexit(1); } 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; *(uint16_t*)0x205fafd2 = 0x18; *(uint32_t*)0x205fafd4 = 1; *(uint32_t*)0x205fafd8 = 0; *(uint32_t*)0x205fafdc = r[0]; *(uint16_t*)0x205fafe0 = 2; *(uint16_t*)0x205fafe2 = htobe16(0x4e21); *(uint8_t*)0x205fafe4 = 0xac; *(uint8_t*)0x205fafe5 = 0x14; *(uint8_t*)0x205fafe6 = 0; *(uint8_t*)0x205fafe7 = 0xbb; *(uint8_t*)0x205fafe8 = 0; *(uint8_t*)0x205fafe9 = 0; *(uint8_t*)0x205fafea = 0; *(uint8_t*)0x205fafeb = 0; *(uint8_t*)0x205fafec = 0; *(uint8_t*)0x205fafed = 0; *(uint8_t*)0x205fafee = 0; *(uint8_t*)0x205fafef = 0; *(uint32_t*)0x205faff0 = 4; *(uint32_t*)0x205faff4 = 0; *(uint32_t*)0x205faff8 = 2; *(uint32_t*)0x205faffc = 0; syscall(__NR_connect, r[1], 0x205fafd2, 0x2e); *(uint16_t*)0x20000000 = 0xa; *(uint16_t*)0x20000002 = htobe16(0x4e20); *(uint32_t*)0x20000004 = 0x1000; *(uint8_t*)0x20000008 = 0; *(uint8_t*)0x20000009 = 0; *(uint8_t*)0x2000000a = 0; *(uint8_t*)0x2000000b = 0; *(uint8_t*)0x2000000c = 0; *(uint8_t*)0x2000000d = 0; *(uint8_t*)0x2000000e = 0; *(uint8_t*)0x2000000f = 0; *(uint8_t*)0x20000010 = 0; *(uint8_t*)0x20000011 = 0; *(uint8_t*)0x20000012 = -1; *(uint8_t*)0x20000013 = -1; *(uint32_t*)0x20000014 = htobe32(0x7f000001); *(uint32_t*)0x20000018 = 1; syscall(__NR_connect, r[0], 0x20000000, 0x1c); *(uint16_t*)0x2064eff0 = 4; *(uint16_t*)0x2064eff2 = htobe16(0); *(uint32_t*)0x2064eff4 = htobe32(0x800); memcpy((void*)0x2064eff8, "\x86\x46\x2e\xb9\x66\xdc", 6); *(uint8_t*)0x2064effe = 8; *(uint8_t*)0x2064efff = 0; syscall(__NR_sendto, r[1], 0x20de7000, 0, 0xc3fe68eda9554f8b, 0x2064eff0, 0x80); syz_extract_tcp_res(0x200001c0, 1, 0); } int main() { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); use_temporary_dir(); int pid = do_sandbox_none(); int status = 0; while (waitpid(pid, &status, __WALL) != pid) { } return 0; }