// https://syzkaller.appspot.com/bug?id=fbdd184fa117ff48a7928f7b3d8d30792c8e4ba8 // 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 __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; \ } 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 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(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 (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: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" #define IFF_NAPI 0x0010 #define IFF_NAPI_FRAGS 0x0020 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 | 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("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); } #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); } long r[79]; void loop() { memset(r, -1, sizeof(r)); r[0] = syscall(__NR_mmap, 0x20000000ul, 0xb3f000ul, 0x3ul, 0x32ul, 0xfffffffffffffffful, 0x0ul); memcpy((void*)0x20000000, "\xef\xad\x07\x00\x00\xa7", 6); *(uint8_t*)0x20000006 = (uint8_t)0x0; *(uint8_t*)0x20000007 = (uint8_t)0x0; *(uint8_t*)0x20000008 = (uint8_t)0x0; *(uint8_t*)0x20000009 = (uint8_t)0x0; *(uint8_t*)0x2000000a = (uint8_t)0x0; *(uint8_t*)0x2000000b = (uint8_t)0x0; *(uint16_t*)0x2000000c = (uint16_t)0x8; STORE_BY_BITMASK(uint8_t, 0x2000000e, 0x5, 0, 4); STORE_BY_BITMASK(uint8_t, 0x2000000e, 0x4, 4, 4); STORE_BY_BITMASK(uint8_t, 0x2000000f, 0x0, 0, 2); STORE_BY_BITMASK(uint8_t, 0x2000000f, 0x40, 2, 6); *(uint16_t*)0x20000010 = (uint16_t)0x6c00; *(uint16_t*)0x20000012 = (uint16_t)0x6400; *(uint16_t*)0x20000014 = (uint16_t)0x0; *(uint8_t*)0x20000016 = (uint8_t)0x0; *(uint8_t*)0x20000017 = (uint8_t)0x1; *(uint16_t*)0x20000018 = (uint16_t)0x0; *(uint8_t*)0x2000001a = (uint8_t)0xac; *(uint8_t*)0x2000001b = (uint8_t)0x14; *(uint8_t*)0x2000001c = (uint8_t)0x0; *(uint8_t*)0x2000001d = (uint8_t)0xbb; *(uint8_t*)0x2000001e = (uint8_t)0xac; *(uint8_t*)0x2000001f = (uint8_t)0x14; *(uint8_t*)0x20000020 = (uint8_t)0x0; *(uint8_t*)0x20000021 = (uint8_t)0xaa; *(uint8_t*)0x20000022 = (uint8_t)0x3; *(uint8_t*)0x20000023 = (uint8_t)0x4; *(uint16_t*)0x20000024 = (uint16_t)0x0; *(uint8_t*)0x20000026 = (uint8_t)0x0; *(uint8_t*)0x20000027 = (uint8_t)0x0; *(uint16_t*)0x20000028 = (uint16_t)0x0; STORE_BY_BITMASK(uint8_t, 0x2000002a, 0x14, 0, 4); STORE_BY_BITMASK(uint8_t, 0x2000002a, 0x4, 4, 4); STORE_BY_BITMASK(uint8_t, 0x2000002b, 0x0, 0, 2); STORE_BY_BITMASK(uint8_t, 0x2000002b, 0x0, 2, 6); *(uint16_t*)0x2000002c = (uint16_t)0x0; *(uint16_t*)0x2000002e = (uint16_t)0x6400; *(uint16_t*)0x20000030 = (uint16_t)0x0; *(uint8_t*)0x20000032 = (uint8_t)0x0; *(uint8_t*)0x20000033 = (uint8_t)0x200000001; *(uint16_t*)0x20000034 = (uint16_t)0x0; *(uint32_t*)0x20000036 = (uint32_t)0x100007f; *(uint32_t*)0x2000003a = (uint32_t)0x0; *(uint8_t*)0x2000003e = (uint8_t)0x83; *(uint8_t*)0x2000003f = (uint8_t)0x23; *(uint8_t*)0x20000040 = (uint8_t)0x0; *(uint32_t*)0x20000041 = (uint32_t)0x100007f; *(uint32_t*)0x20000045 = (uint32_t)0x20000e0; *(uint8_t*)0x20000049 = (uint8_t)0xac; *(uint8_t*)0x2000004a = (uint8_t)0x14; *(uint8_t*)0x2000004b = (uint8_t)0x0; *(uint8_t*)0x2000004c = (uint8_t)0xaa; *(uint32_t*)0x2000004d = (uint32_t)0x20000e0; *(uint32_t*)0x20000051 = (uint32_t)0x100007f; *(uint32_t*)0x20000055 = (uint32_t)0x10000e0; *(uint32_t*)0x20000059 = (uint32_t)0x0; *(uint8_t*)0x2000005d = (uint8_t)0xac; *(uint8_t*)0x2000005e = (uint8_t)0x14; *(uint8_t*)0x2000005f = (uint8_t)0x0; *(uint8_t*)0x20000060 = (uint8_t)0xaa; *(uint8_t*)0x20000061 = (uint8_t)0x44; *(uint8_t*)0x20000062 = (uint8_t)0x4; *(uint8_t*)0x20000063 = (uint8_t)0x0; STORE_BY_BITMASK(uint8_t, 0x20000064, 0x3, 0, 4); STORE_BY_BITMASK(uint8_t, 0x20000064, 0x0, 4, 4); *(uint8_t*)0x20000065 = (uint8_t)0x89; *(uint8_t*)0x20000066 = (uint8_t)0xf; *(uint8_t*)0x20000067 = (uint8_t)0x0; *(uint32_t*)0x20000068 = (uint32_t)0x10000; *(uint32_t*)0x2000006c = (uint32_t)0x10000e0; *(uint32_t*)0x20000070 = (uint32_t)0x10000e0; *(uint8_t*)0x20000074 = (uint8_t)0x1; *(uint8_t*)0x20000075 = (uint8_t)0x0; *(uint8_t*)0x20000076 = (uint8_t)0x2; struct csum_inet csum_76; csum_inet_init(&csum_76); csum_inet_update(&csum_76, (const uint8_t*)0x20000022, 88); *(uint16_t*)0x20000024 = csum_inet_digest(&csum_76); struct csum_inet csum_77; csum_inet_init(&csum_77); csum_inet_update(&csum_77, (const uint8_t*)0x2000000e, 20); *(uint16_t*)0x20000018 = csum_inet_digest(&csum_77); r[78] = syz_emit_ethernet(0x7aul, 0x20000000ul, 0x20000000ul); } int main() { setup_tun(0, true); loop(); return 0; }