// https://syzkaller.appspot.com/bug?id=15c5543925399f71beb72b92dcc266279aeaf121 // autogenerated by syzkaller (https://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 #include #include #include #include static void use_temporary_dir(void) { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) exit(1); if (chmod(tmpdir, 0777)) exit(1); if (chdir(tmpdir)) exit(1); } 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) { int err = errno; close(fd); errno = err; return false; } close(fd); return true; } struct nlmsg { char* pos; int nesting; struct nlattr* nested[8]; char buf[1024]; }; static struct nlmsg nlmsg; static void netlink_init(struct nlmsg* nlmsg, int typ, int flags, const void* data, int size) { memset(nlmsg, 0, sizeof(*nlmsg)); struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf; hdr->nlmsg_type = typ; hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags; memcpy(hdr + 1, data, size); nlmsg->pos = (char*)(hdr + 1) + NLMSG_ALIGN(size); } static void netlink_attr(struct nlmsg* nlmsg, int typ, const void* data, int size) { struct nlattr* attr = (struct nlattr*)nlmsg->pos; attr->nla_len = sizeof(*attr) + size; attr->nla_type = typ; memcpy(attr + 1, data, size); nlmsg->pos += NLMSG_ALIGN(attr->nla_len); } static int netlink_send_ext(struct nlmsg* nlmsg, int sock, uint16_t reply_type, int* reply_len) { if (nlmsg->pos > nlmsg->buf + sizeof(nlmsg->buf) || nlmsg->nesting) exit(1); struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf; hdr->nlmsg_len = nlmsg->pos - nlmsg->buf; struct sockaddr_nl addr; memset(&addr, 0, sizeof(addr)); addr.nl_family = AF_NETLINK; unsigned n = sendto(sock, nlmsg->buf, hdr->nlmsg_len, 0, (struct sockaddr*)&addr, sizeof(addr)); if (n != hdr->nlmsg_len) exit(1); n = recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0); if (hdr->nlmsg_type == NLMSG_DONE) { *reply_len = 0; return 0; } if (n < sizeof(struct nlmsghdr)) exit(1); if (reply_len && hdr->nlmsg_type == reply_type) { *reply_len = n; return 0; } if (n < sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr)) exit(1); if (hdr->nlmsg_type != NLMSG_ERROR) exit(1); return -((struct nlmsgerr*)(hdr + 1))->error; } static int netlink_send(struct nlmsg* nlmsg, int sock) { return netlink_send_ext(nlmsg, sock, 0, NULL); } static void netlink_device_change(struct nlmsg* nlmsg, int sock, const char* name, bool up, const char* master, const void* mac, int macsize, const char* new_name) { struct ifinfomsg hdr; memset(&hdr, 0, sizeof(hdr)); if (up) hdr.ifi_flags = hdr.ifi_change = IFF_UP; hdr.ifi_index = if_nametoindex(name); netlink_init(nlmsg, RTM_NEWLINK, 0, &hdr, sizeof(hdr)); if (new_name) netlink_attr(nlmsg, IFLA_IFNAME, new_name, strlen(new_name)); if (master) { int ifindex = if_nametoindex(master); netlink_attr(nlmsg, IFLA_MASTER, &ifindex, sizeof(ifindex)); } if (macsize) netlink_attr(nlmsg, IFLA_ADDRESS, mac, macsize); int err = netlink_send(nlmsg, sock); (void)err; } static int netlink_add_addr(struct nlmsg* nlmsg, int sock, const char* dev, const void* addr, int addrsize) { struct ifaddrmsg hdr; memset(&hdr, 0, sizeof(hdr)); hdr.ifa_family = addrsize == 4 ? AF_INET : AF_INET6; hdr.ifa_prefixlen = addrsize == 4 ? 24 : 120; hdr.ifa_scope = RT_SCOPE_UNIVERSE; hdr.ifa_index = if_nametoindex(dev); netlink_init(nlmsg, RTM_NEWADDR, NLM_F_CREATE | NLM_F_REPLACE, &hdr, sizeof(hdr)); netlink_attr(nlmsg, IFA_LOCAL, addr, addrsize); netlink_attr(nlmsg, IFA_ADDRESS, addr, addrsize); return netlink_send(nlmsg, sock); } static void netlink_add_addr4(struct nlmsg* nlmsg, int sock, const char* dev, const char* addr) { struct in_addr in_addr; inet_pton(AF_INET, addr, &in_addr); int err = netlink_add_addr(nlmsg, sock, dev, &in_addr, sizeof(in_addr)); (void)err; } static void netlink_add_addr6(struct nlmsg* nlmsg, int sock, const char* dev, const char* addr) { struct in6_addr in6_addr; inet_pton(AF_INET6, addr, &in6_addr); int err = netlink_add_addr(nlmsg, sock, dev, &in6_addr, sizeof(in6_addr)); (void)err; } static void netlink_add_neigh(struct nlmsg* nlmsg, int sock, const char* name, const void* addr, int addrsize, const void* mac, int macsize) { struct ndmsg hdr; memset(&hdr, 0, sizeof(hdr)); hdr.ndm_family = addrsize == 4 ? AF_INET : AF_INET6; hdr.ndm_ifindex = if_nametoindex(name); hdr.ndm_state = NUD_PERMANENT; netlink_init(nlmsg, RTM_NEWNEIGH, NLM_F_EXCL | NLM_F_CREATE, &hdr, sizeof(hdr)); netlink_attr(nlmsg, NDA_DST, addr, addrsize); netlink_attr(nlmsg, NDA_LLADDR, mac, macsize); int err = netlink_send(nlmsg, sock); (void)err; } static int tunfd = -1; static int tun_frags_enabled; #define TUN_IFACE "syz_tun" #define LOCAL_MAC 0xaaaaaaaaaaaa #define REMOTE_MAC 0xaaaaaaaaaabb #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 = 240; if (dup2(tunfd, kTunFd) < 0) exit(1); 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; if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) { exit(1); } char sysctl[64]; sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/accept_dad", TUN_IFACE); write_file(sysctl, "0"); sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/router_solicitations", TUN_IFACE); write_file(sysctl, "0"); int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); if (sock == -1) exit(1); netlink_add_addr4(&nlmsg, sock, TUN_IFACE, LOCAL_IPV4); netlink_add_addr6(&nlmsg, sock, TUN_IFACE, LOCAL_IPV6); uint64_t macaddr = REMOTE_MAC; struct in_addr in_addr; inet_pton(AF_INET, REMOTE_IPV4, &in_addr); netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in_addr, sizeof(in_addr), &macaddr, ETH_ALEN); struct in6_addr in6_addr; inet_pton(AF_INET6, REMOTE_IPV6, &in6_addr); netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in6_addr, sizeof(in6_addr), &macaddr, ETH_ALEN); macaddr = LOCAL_MAC; netlink_device_change(&nlmsg, sock, TUN_IFACE, true, 0, &macaddr, ETH_ALEN, NULL); close(sock); } static void setup_common() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 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 = (200 << 20); setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 32 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 136 << 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); rlim.rlim_cur = rlim.rlim_max = 256; setrlimit(RLIMIT_NOFILE, &rlim); if (unshare(CLONE_NEWNS)) { } if (unshare(CLONE_NEWIPC)) { } if (unshare(0x02000000)) { } if (unshare(CLONE_NEWUTS)) { } if (unshare(CLONE_SYSVSEM)) { } typedef struct { const char* name; const char* value; } sysctl_t; static const sysctl_t sysctls[] = { {"/proc/sys/kernel/shmmax", "16777216"}, {"/proc/sys/kernel/shmall", "536870912"}, {"/proc/sys/kernel/shmmni", "1024"}, {"/proc/sys/kernel/msgmax", "8192"}, {"/proc/sys/kernel/msgmni", "1024"}, {"/proc/sys/kernel/msgmnb", "1024"}, {"/proc/sys/kernel/sem", "1024 1048576 500 1024"}, }; unsigned i; for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++) write_file(sysctls[i].name, sysctls[i].value); } static int wait_for_loop(int pid) { if (pid < 0) exit(1); int status = 0; while (waitpid(-1, &status, __WALL) != pid) { } return WEXITSTATUS(status); } static void drop_caps(void) { 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)) exit(1); const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE); cap_data[0].effective &= ~drop; cap_data[0].permitted &= ~drop; cap_data[0].inheritable &= ~drop; if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1); } static int do_sandbox_none(void) { if (unshare(CLONE_NEWPID)) { } int pid = fork(); if (pid != 0) return wait_for_loop(pid); setup_common(); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } initialize_tun(); loop(); exit(1); } #ifndef __NR_getsockname #define __NR_getsockname 367 #endif #ifndef __NR_mmap #define __NR_mmap 192 #endif #ifndef __NR_sendmsg #define __NR_sendmsg 370 #endif #ifndef __NR_socket #define __NR_socket 359 #endif #undef __NR_mmap #define __NR_mmap __NR_mmap2 uint64_t r[5] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0x0}; void loop(void) { intptr_t res = 0; res = syscall(__NR_socket, 0x10, 3, 0); if (res != -1) r[0] = res; res = syscall(__NR_socket, 0x10, 3, 0); if (res != -1) r[1] = res; res = syscall(__NR_socket, 0x10, 3, 0); if (res != -1) r[2] = res; res = syscall(__NR_socket, 0x10, 0x803, 0); if (res != -1) r[3] = res; *(uint32_t*)0x20000280 = 0; *(uint32_t*)0x20000284 = 0; *(uint32_t*)0x20000288 = 0x20000180; *(uint32_t*)0x20000180 = 0; *(uint32_t*)0x20000184 = 0; *(uint32_t*)0x2000028c = 1; *(uint32_t*)0x20000290 = 0; *(uint32_t*)0x20000294 = 0; *(uint32_t*)0x20000298 = 0; syscall(__NR_sendmsg, (intptr_t)r[3], 0x20000280, 0); *(uint32_t*)0x200002c0 = 0x14; res = syscall(__NR_getsockname, (intptr_t)r[3], 0x20000100, 0x200002c0); if (res != -1) r[4] = *(uint32_t*)0x20000104; *(uint32_t*)0x20000240 = 0; *(uint32_t*)0x20000244 = 0; *(uint32_t*)0x20000248 = 0x20000140; *(uint32_t*)0x20000140 = 0x200003c0; memcpy((void*)0x200003c0, "\x38\x00\x00\x00\x24\x00\x07\x05\x00\x00\x00\x40" "\x07\xa2\xa3\x00\x05\x00\x00\x00", 20); *(uint32_t*)0x200003d4 = r[4]; memcpy((void*)0x200003d8, "\x00\x00\x00\x00\xff\xff\xff\xff\x00\x00\x00\x00" "\x09\x00\x01\x00\x68\x66\x73\x63\x00\x00\x00\x00" "\x08\x00\x02\x00\x00\x00\x00\x00", 32); *(uint32_t*)0x20000144 = 0x38; *(uint32_t*)0x2000024c = 1; *(uint32_t*)0x20000250 = 0; *(uint32_t*)0x20000254 = 0; *(uint32_t*)0x20000258 = 0; syscall(__NR_sendmsg, (intptr_t)r[2], 0x20000240, 0); *(uint32_t*)0x200001c0 = 0; *(uint32_t*)0x200001c4 = 0; *(uint32_t*)0x200001c8 = 0x20000180; *(uint32_t*)0x20000180 = 0x20000580; *(uint32_t*)0x20000580 = 0x3c; *(uint16_t*)0x20000584 = 0x2c; *(uint16_t*)0x20000586 = 0xd27; *(uint32_t*)0x20000588 = 0; *(uint32_t*)0x2000058c = 0; *(uint8_t*)0x20000590 = 0; *(uint8_t*)0x20000591 = 0; *(uint16_t*)0x20000592 = 0; *(uint32_t*)0x20000594 = r[4]; *(uint16_t*)0x20000598 = 0; *(uint16_t*)0x2000059a = 0; *(uint16_t*)0x2000059c = 0; *(uint16_t*)0x2000059e = 0; *(uint16_t*)0x200005a0 = 4; *(uint16_t*)0x200005a2 = 0xfff1; *(uint16_t*)0x200005a4 = 0xc; *(uint16_t*)0x200005a6 = 1; memcpy((void*)0x200005a8, "tcindex\000", 8); *(uint16_t*)0x200005b0 = 0xc; *(uint16_t*)0x200005b2 = 2; *(uint16_t*)0x200005b4 = 6; *(uint16_t*)0x200005b6 = 2; *(uint16_t*)0x200005b8 = 0; *(uint32_t*)0x20000184 = 0x3c; *(uint32_t*)0x200001cc = 1; *(uint32_t*)0x200001d0 = 0; *(uint32_t*)0x200001d4 = 0; *(uint32_t*)0x200001d8 = 0; syscall(__NR_sendmsg, (intptr_t)r[1], 0x200001c0, 0); *(uint32_t*)0x200001c0 = 0; *(uint32_t*)0x200001c4 = 0; *(uint32_t*)0x200001c8 = 0x20000180; *(uint32_t*)0x20000180 = 0x20000400; *(uint32_t*)0x20000400 = 0x3c; *(uint16_t*)0x20000404 = 0x2c; *(uint16_t*)0x20000406 = 0xd27; *(uint32_t*)0x20000408 = 0; *(uint32_t*)0x2000040c = 0; *(uint8_t*)0x20000410 = 0; *(uint8_t*)0x20000411 = 0; *(uint16_t*)0x20000412 = 0xf0; *(uint32_t*)0x20000414 = r[4]; *(uint16_t*)0x20000418 = 2; *(uint16_t*)0x2000041a = 0; *(uint16_t*)0x2000041c = 0; *(uint16_t*)0x2000041e = 0; *(uint16_t*)0x20000420 = 0; *(uint16_t*)0x20000422 = 0xfff1; *(uint16_t*)0x20000424 = 0xc; *(uint16_t*)0x20000426 = 1; memcpy((void*)0x20000428, "tcindex\000", 8); *(uint16_t*)0x20000430 = 0xc; *(uint16_t*)0x20000432 = 2; *(uint16_t*)0x20000434 = 8; *(uint16_t*)0x20000436 = 1; *(uint32_t*)0x20000438 = 0; *(uint32_t*)0x20000184 = 0x3c; *(uint32_t*)0x200001cc = 1; *(uint32_t*)0x200001d0 = 0; *(uint32_t*)0x200001d4 = 0; *(uint32_t*)0x200001d8 = 0; syscall(__NR_sendmsg, (intptr_t)r[0], 0x200001c0, 0); } int main(void) { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); use_temporary_dir(); do_sandbox_none(); return 0; }