// https://syzkaller.appspot.com/bug?id=685f059b7e5b6ed6e4dd6c92755ea01acedf5302 // 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 #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 #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); } #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 __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); } 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 #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; NONFAILING(full = frags->full); NONFAILING(count = frags->count); if (count > MAX_FRAGS) count = MAX_FRAGS; for (i = 0; i < count && length != 0; i++) { uint32_t size = 0; NONFAILING(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); } 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 bool write_file(const char* file, const char* what, ...) { char buf[1024]; va_list args; va_start(args, what); vsnprintf(buf, sizeof(buf), what, args); va_end(args); buf[sizeof(buf) - 1] = 0; int len = strlen(buf); int fd = open(file, O_WRONLY | O_CLOEXEC); if (fd == -1) return false; if (write(fd, buf, len) != len) { close(fd); return false; } close(fd); return true; } static int real_uid; static int real_gid; __attribute__((aligned(64 << 10))) static char sandbox_stack[1 << 20]; static int namespace_sandbox_proc(void* arg) { sandbox_common(); write_file("/proc/self/setgroups", "deny"); if (!write_file("/proc/self/uid_map", "0 %d 1\n", real_uid)) fail("write of /proc/self/uid_map failed"); if (!write_file("/proc/self/gid_map", "0 %d 1\n", real_gid)) fail("write of /proc/self/gid_map failed"); if (unshare(CLONE_NEWNET)) fail("unshare(CLONE_NEWNET)"); setup_tun((long)arg >> 1, (long)arg & 1); if (mkdir("./syz-tmp", 0777)) fail("mkdir(syz-tmp) failed"); if (mount("", "./syz-tmp", "tmpfs", 0, NULL)) fail("mount(tmpfs) failed"); if (mkdir("./syz-tmp/newroot", 0777)) fail("mkdir failed"); if (mkdir("./syz-tmp/newroot/dev", 0700)) fail("mkdir failed"); if (mount("/dev", "./syz-tmp/newroot/dev", NULL, MS_BIND | MS_REC | MS_PRIVATE, NULL)) fail("mount(dev) failed"); if (mkdir("./syz-tmp/newroot/proc", 0700)) fail("mkdir failed"); if (mount(NULL, "./syz-tmp/newroot/proc", "proc", 0, NULL)) fail("mount(proc) failed"); if (mkdir("./syz-tmp/newroot/selinux", 0700)) fail("mkdir failed"); if (mount("/selinux", "./syz-tmp/newroot/selinux", NULL, MS_BIND | MS_REC | MS_PRIVATE, NULL)) fail("mount(selinuxfs) failed"); if (mkdir("./syz-tmp/pivot", 0777)) fail("mkdir failed"); if (syscall(SYS_pivot_root, "./syz-tmp", "./syz-tmp/pivot")) { if (chdir("./syz-tmp")) fail("chdir failed"); } else { if (chdir("/")) fail("chdir failed"); if (umount2("./pivot", MNT_DETACH)) fail("umount failed"); } if (chroot("./newroot")) fail("chroot failed"); if (chdir("/")) fail("chdir failed"); struct __user_cap_header_struct cap_hdr = {}; struct __user_cap_data_struct cap_data[2] = {}; cap_hdr.version = _LINUX_CAPABILITY_VERSION_3; cap_hdr.pid = getpid(); if (syscall(SYS_capget, &cap_hdr, &cap_data)) fail("capget failed"); cap_data[0].effective &= ~(1 << CAP_SYS_PTRACE); cap_data[0].permitted &= ~(1 << CAP_SYS_PTRACE); cap_data[0].inheritable &= ~(1 << CAP_SYS_PTRACE); if (syscall(SYS_capset, &cap_hdr, &cap_data)) fail("capset failed"); loop(); doexit(1); } static int do_sandbox_namespace(int executor_pid, bool enable_tun) { int pid; real_uid = getuid(); real_gid = getgid(); mprotect(sandbox_stack, 4096, PROT_NONE); void* arg = (void*)(long)((executor_pid << 1) | enable_tun); pid = clone(namespace_sandbox_proc, &sandbox_stack[sizeof(sandbox_stack) - 64], CLONE_NEWUSER | CLONE_NEWPID, arg); if (pid < 0) fail("sandbox clone failed"); return pid; } #ifndef __NR_socket #define __NR_socket 359 #endif #ifndef __NR_setsockopt #define __NR_setsockopt 366 #endif #ifndef __NR_sendto #define __NR_sendto 369 #endif #ifndef __NR_mmap #define __NR_mmap 192 #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, 0x11, 2, 0x300); NONFAILING(*(uint32_t*)0x20010ffc = 1); syscall(__NR_setsockopt, r[0], 0x107, 0x14, 0x20010ffc, 4); NONFAILING(*(uint16_t*)0x20008000 = 0xa); NONFAILING(*(uint16_t*)0x20008002 = htobe16(0x4e23)); NONFAILING(*(uint32_t*)0x20008004 = 5); NONFAILING(*(uint8_t*)0x20008008 = 0xfe); NONFAILING(*(uint8_t*)0x20008009 = 0x80); NONFAILING(*(uint8_t*)0x2000800a = 0); NONFAILING(*(uint8_t*)0x2000800b = 0); NONFAILING(*(uint8_t*)0x2000800c = 0); NONFAILING(*(uint8_t*)0x2000800d = 0); NONFAILING(*(uint8_t*)0x2000800e = 0); NONFAILING(*(uint8_t*)0x2000800f = 0); NONFAILING(*(uint8_t*)0x20008010 = 0); NONFAILING(*(uint8_t*)0x20008011 = 0); NONFAILING(*(uint8_t*)0x20008012 = 0); NONFAILING(*(uint8_t*)0x20008013 = 0); NONFAILING(*(uint8_t*)0x20008014 = 0); NONFAILING(*(uint8_t*)0x20008015 = 0); NONFAILING(*(uint8_t*)0x20008016 = 0); NONFAILING(*(uint8_t*)0x20008017 = 0xaa); NONFAILING(*(uint32_t*)0x20008018 = 0); syscall(__NR_sendto, r[0], 0x20003fd9, 0, 0, 0x20008000, 0x1c); NONFAILING(*(uint8_t*)0x206eef62 = 0xaa); NONFAILING(*(uint8_t*)0x206eef63 = 0xaa); NONFAILING(*(uint8_t*)0x206eef64 = 0xaa); NONFAILING(*(uint8_t*)0x206eef65 = 0xaa); NONFAILING(*(uint8_t*)0x206eef66 = 0); NONFAILING(*(uint8_t*)0x206eef67 = 0xaa); NONFAILING(*(uint8_t*)0x206eef68 = -1); NONFAILING(*(uint8_t*)0x206eef69 = -1); NONFAILING(*(uint8_t*)0x206eef6a = -1); NONFAILING(*(uint8_t*)0x206eef6b = -1); NONFAILING(*(uint8_t*)0x206eef6c = -1); NONFAILING(*(uint8_t*)0x206eef6d = -1); NONFAILING(*(uint16_t*)0x206eef6e = htobe16(0x800)); NONFAILING(STORE_BY_BITMASK(uint8_t, 0x206eef70, 0xbd, 0, 4)); NONFAILING(STORE_BY_BITMASK(uint8_t, 0x206eef70, 4, 4, 4)); NONFAILING(STORE_BY_BITMASK(uint8_t, 0x206eef71, 0, 0, 2)); NONFAILING(STORE_BY_BITMASK(uint8_t, 0x206eef71, 0, 2, 6)); NONFAILING(*(uint16_t*)0x206eef72 = htobe16(0x34)); NONFAILING(*(uint16_t*)0x206eef74 = 0); NONFAILING(*(uint16_t*)0x206eef76 = htobe16(0)); NONFAILING(*(uint8_t*)0x206eef78 = 0); NONFAILING(*(uint8_t*)0x206eef79 = 1); NONFAILING(*(uint16_t*)0x206eef7a = 0); NONFAILING(*(uint32_t*)0x206eef7c = htobe32(0xfffffe02)); NONFAILING(*(uint8_t*)0x206eef80 = 0xac); NONFAILING(*(uint8_t*)0x206eef81 = 0x14); NONFAILING(*(uint8_t*)0x206eef82 = 0); NONFAILING(*(uint8_t*)0x206eef83 = 0); NONFAILING(*(uint8_t*)0x206eef84 = 0x83); NONFAILING(*(uint8_t*)0x206eef85 = 0xa3); NONFAILING(*(uint8_t*)0x206eef86 = 0); NONFAILING(*(uint8_t*)0x206eef88 = 3); NONFAILING(*(uint8_t*)0x206eef89 = 0); NONFAILING(*(uint16_t*)0x206eef8a = 0); NONFAILING(*(uint8_t*)0x206eef8c = 0); NONFAILING(*(uint8_t*)0x206eef8d = 0); NONFAILING(*(uint16_t*)0x206eef8e = htobe16(0)); NONFAILING(STORE_BY_BITMASK(uint8_t, 0x206eef90, 5, 0, 4)); NONFAILING(STORE_BY_BITMASK(uint8_t, 0x206eef90, 4, 4, 4)); NONFAILING(STORE_BY_BITMASK(uint8_t, 0x206eef91, 0, 0, 2)); NONFAILING(STORE_BY_BITMASK(uint8_t, 0x206eef91, 0, 2, 6)); NONFAILING(*(uint16_t*)0x206eef92 = htobe16(0)); NONFAILING(*(uint16_t*)0x206eef94 = 0); NONFAILING(*(uint16_t*)0x206eef96 = htobe16(0)); NONFAILING(*(uint8_t*)0x206eef98 = 0); NONFAILING(*(uint8_t*)0x206eef99 = 0); NONFAILING(*(uint16_t*)0x206eef9a = htobe16(0)); NONFAILING(*(uint32_t*)0x206eef9c = htobe32(-1)); NONFAILING(*(uint8_t*)0x206eefa0 = 0xac); NONFAILING(*(uint8_t*)0x206eefa1 = 0x14); NONFAILING(*(uint8_t*)0x206eefa2 = 0); NONFAILING(*(uint8_t*)0x206eefa3 = 0); NONFAILING(*(uint32_t*)0x205ecff8 = 0); NONFAILING(*(uint32_t*)0x205ecffc = 0); struct csum_inet csum_1; csum_inet_init(&csum_1); NONFAILING(csum_inet_update(&csum_1, (const uint8_t*)0x206eef88, 28)); NONFAILING(*(uint16_t*)0x206eef8a = csum_inet_digest(&csum_1)); struct csum_inet csum_2; csum_inet_init(&csum_2); NONFAILING(csum_inet_update(&csum_2, (const uint8_t*)0x206eef70, 24)); NONFAILING(*(uint16_t*)0x206eef7a = csum_inet_digest(&csum_2)); syz_emit_ethernet(0x42, 0x206eef62, 0x205ecff8); } int main() { install_segv_handler(); use_temporary_dir(); int pid = do_sandbox_namespace(0, true); int status = 0; while (waitpid(pid, &status, __WALL) != pid) { } return 0; }