// https://syzkaller.appspot.com/bug?id=da205accc13a9080d2f8991b8cd6950b5486317c // 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 unsigned long long procid; 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[4096]; }; 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; if (size > 0) 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 (reply_len) *reply_len = 0; if (hdr->nlmsg_type == NLMSG_DONE) 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 int netlink_query_family_id(struct nlmsg* nlmsg, int sock, const char* family_name) { struct genlmsghdr genlhdr; memset(&genlhdr, 0, sizeof(genlhdr)); genlhdr.cmd = CTRL_CMD_GETFAMILY; netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr)); netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, family_name, strnlen(family_name, GENL_NAMSIZ - 1) + 1); int n = 0; int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n); if (err < 0) { return -1; } uint16_t id = 0; struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN + NLMSG_ALIGN(sizeof(genlhdr))); for (; (char*)attr < nlmsg->buf + n; attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) { if (attr->nla_type == CTRL_ATTR_FAMILY_ID) { id = *(uint16_t*)(attr + 1); break; } } if (!id) { return -1; } recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0); return id; } static struct nlmsg nlmsg; #define WIFI_INITIAL_DEVICE_COUNT 2 #define WIFI_MAC_BASE \ { \ 0x08, 0x02, 0x11, 0x00, 0x00, 0x00 \ } #define WIFI_IBSS_BSSID \ { \ 0x50, 0x50, 0x50, 0x50, 0x50, 0x50 \ } #define WIFI_IBSS_SSID \ { \ 0x10, 0x10, 0x10, 0x10, 0x10, 0x10 \ } #define WIFI_DEFAULT_FREQUENCY 2412 #define WIFI_DEFAULT_SIGNAL 0 #define WIFI_DEFAULT_RX_RATE 1 #define HWSIM_CMD_REGISTER 1 #define HWSIM_CMD_FRAME 2 #define HWSIM_CMD_NEW_RADIO 4 #define HWSIM_ATTR_SUPPORT_P2P_DEVICE 14 #define HWSIM_ATTR_PERM_ADDR 22 #define IF_OPER_UP 6 struct join_ibss_props { int wiphy_freq; bool wiphy_freq_fixed; uint8_t* mac; uint8_t* ssid; int ssid_len; }; static int set_interface_state(const char* interface_name, int on) { struct ifreq ifr; int sock = socket(AF_INET, SOCK_DGRAM, 0); if (sock < 0) { return -1; } memset(&ifr, 0, sizeof(ifr)); strcpy(ifr.ifr_name, interface_name); int ret = ioctl(sock, SIOCGIFFLAGS, &ifr); if (ret < 0) { close(sock); return -1; } if (on) ifr.ifr_flags |= IFF_UP; else ifr.ifr_flags &= ~IFF_UP; ret = ioctl(sock, SIOCSIFFLAGS, &ifr); close(sock); if (ret < 0) { return -1; } return 0; } static int nl80211_set_interface(struct nlmsg* nlmsg, int sock, int nl80211_family, uint32_t ifindex, uint32_t iftype) { struct genlmsghdr genlhdr; memset(&genlhdr, 0, sizeof(genlhdr)); genlhdr.cmd = NL80211_CMD_SET_INTERFACE; netlink_init(nlmsg, nl80211_family, 0, &genlhdr, sizeof(genlhdr)); netlink_attr(nlmsg, NL80211_ATTR_IFINDEX, &ifindex, sizeof(ifindex)); netlink_attr(nlmsg, NL80211_ATTR_IFTYPE, &iftype, sizeof(iftype)); int err = netlink_send(nlmsg, sock); if (err < 0) { return -1; } return 0; } static int nl80211_join_ibss(struct nlmsg* nlmsg, int sock, int nl80211_family, uint32_t ifindex, struct join_ibss_props* props) { struct genlmsghdr genlhdr; memset(&genlhdr, 0, sizeof(genlhdr)); genlhdr.cmd = NL80211_CMD_JOIN_IBSS; netlink_init(nlmsg, nl80211_family, 0, &genlhdr, sizeof(genlhdr)); netlink_attr(nlmsg, NL80211_ATTR_IFINDEX, &ifindex, sizeof(ifindex)); netlink_attr(nlmsg, NL80211_ATTR_SSID, props->ssid, props->ssid_len); netlink_attr(nlmsg, NL80211_ATTR_WIPHY_FREQ, &(props->wiphy_freq), sizeof(props->wiphy_freq)); if (props->mac) netlink_attr(nlmsg, NL80211_ATTR_MAC, props->mac, ETH_ALEN); if (props->wiphy_freq_fixed) netlink_attr(nlmsg, NL80211_ATTR_FREQ_FIXED, NULL, 0); int err = netlink_send(nlmsg, sock); if (err < 0) { return -1; } return 0; } static int get_ifla_operstate(struct nlmsg* nlmsg, int ifindex) { struct ifinfomsg info; memset(&info, 0, sizeof(info)); info.ifi_family = AF_UNSPEC; info.ifi_index = ifindex; int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); if (sock == -1) { return -1; } netlink_init(nlmsg, RTM_GETLINK, 0, &info, sizeof(info)); int n; int err = netlink_send_ext(nlmsg, sock, RTM_NEWLINK, &n); close(sock); if (err) { return -1; } struct rtattr* attr = IFLA_RTA(NLMSG_DATA(nlmsg->buf)); for (; RTA_OK(attr, n); attr = RTA_NEXT(attr, n)) { if (attr->rta_type == IFLA_OPERSTATE) return *((int32_t*)RTA_DATA(attr)); } return -1; } static int await_ifla_operstate(struct nlmsg* nlmsg, char* interface, int operstate) { int ifindex = if_nametoindex(interface); while (true) { usleep(1000); int ret = get_ifla_operstate(nlmsg, ifindex); if (ret < 0) return ret; if (ret == operstate) return 0; } return 0; } static int nl80211_setup_ibss_interface(struct nlmsg* nlmsg, int sock, int nl80211_family_id, char* interface, struct join_ibss_props* ibss_props) { int ifindex = if_nametoindex(interface); if (ifindex == 0) { return -1; } int ret = nl80211_set_interface(nlmsg, sock, nl80211_family_id, ifindex, NL80211_IFTYPE_ADHOC); if (ret < 0) { return -1; } ret = set_interface_state(interface, 1); if (ret < 0) { return -1; } ret = nl80211_join_ibss(nlmsg, sock, nl80211_family_id, ifindex, ibss_props); if (ret < 0) { return -1; } return 0; } static int hwsim80211_create_device(struct nlmsg* nlmsg, int sock, int hwsim_family, uint8_t mac_addr[ETH_ALEN]) { struct genlmsghdr genlhdr; memset(&genlhdr, 0, sizeof(genlhdr)); genlhdr.cmd = HWSIM_CMD_NEW_RADIO; netlink_init(nlmsg, hwsim_family, 0, &genlhdr, sizeof(genlhdr)); netlink_attr(nlmsg, HWSIM_ATTR_SUPPORT_P2P_DEVICE, NULL, 0); netlink_attr(nlmsg, HWSIM_ATTR_PERM_ADDR, mac_addr, ETH_ALEN); int err = netlink_send(nlmsg, sock); if (err < 0) { return -1; } return 0; } static void initialize_wifi_devices(void) { uint8_t mac_addr[6] = WIFI_MAC_BASE; int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC); if (sock < 0) { return; } int hwsim_family_id = netlink_query_family_id(&nlmsg, sock, "MAC80211_HWSIM"); int nl80211_family_id = netlink_query_family_id(&nlmsg, sock, "nl80211"); uint8_t ssid[] = WIFI_IBSS_SSID; uint8_t bssid[] = WIFI_IBSS_BSSID; struct join_ibss_props ibss_props = {.wiphy_freq = WIFI_DEFAULT_FREQUENCY, .wiphy_freq_fixed = true, .mac = bssid, .ssid = ssid, .ssid_len = sizeof(ssid)}; for (int device_id = 0; device_id < WIFI_INITIAL_DEVICE_COUNT; device_id++) { mac_addr[5] = device_id; int ret = hwsim80211_create_device(&nlmsg, sock, hwsim_family_id, mac_addr); if (ret < 0) exit(1); char interface[6] = "wlan0"; interface[4] += device_id; if (nl80211_setup_ibss_interface(&nlmsg, sock, nl80211_family_id, interface, &ibss_props) < 0) exit(1); } for (int device_id = 0; device_id < WIFI_INITIAL_DEVICE_COUNT; device_id++) { char interface[6] = "wlan0"; interface[4] += device_id; int ret = await_ifla_operstate(&nlmsg, interface, IF_OPER_UP); if (ret < 0) exit(1); } close(sock); } struct fs_image_segment { void* data; uintptr_t size; uintptr_t offset; }; #define IMAGE_MAX_SEGMENTS 4096 #define IMAGE_MAX_SIZE (129 << 20) #define sys_memfd_create 319 static unsigned long fs_image_segment_check(unsigned long size, unsigned long nsegs, struct fs_image_segment* segs) { if (nsegs > IMAGE_MAX_SEGMENTS) nsegs = IMAGE_MAX_SEGMENTS; for (size_t i = 0; i < nsegs; i++) { if (segs[i].size > IMAGE_MAX_SIZE) segs[i].size = IMAGE_MAX_SIZE; segs[i].offset %= IMAGE_MAX_SIZE; if (segs[i].offset > IMAGE_MAX_SIZE - segs[i].size) segs[i].offset = IMAGE_MAX_SIZE - segs[i].size; if (size < segs[i].offset + segs[i].offset) size = segs[i].offset + segs[i].offset; } if (size > IMAGE_MAX_SIZE) size = IMAGE_MAX_SIZE; return size; } static int setup_loop_device(long unsigned size, long unsigned nsegs, struct fs_image_segment* segs, const char* loopname, int* memfd_p, int* loopfd_p) { int err = 0, loopfd = -1; size = fs_image_segment_check(size, nsegs, segs); int memfd = syscall(sys_memfd_create, "syzkaller", 0); if (memfd == -1) { err = errno; goto error; } if (ftruncate(memfd, size)) { err = errno; goto error_close_memfd; } for (size_t i = 0; i < nsegs; i++) { if (pwrite(memfd, segs[i].data, segs[i].size, segs[i].offset) < 0) { } } loopfd = open(loopname, O_RDWR); if (loopfd == -1) { err = errno; goto error_close_memfd; } if (ioctl(loopfd, LOOP_SET_FD, memfd)) { if (errno != EBUSY) { err = errno; goto error_close_loop; } ioctl(loopfd, LOOP_CLR_FD, 0); usleep(1000); if (ioctl(loopfd, LOOP_SET_FD, memfd)) { err = errno; goto error_close_loop; } } *memfd_p = memfd; *loopfd_p = loopfd; return 0; error_close_loop: close(loopfd); error_close_memfd: close(memfd); error: errno = err; return -1; } static long syz_mount_image(volatile long fsarg, volatile long dir, volatile unsigned long size, volatile unsigned long nsegs, volatile long segments, volatile long flags, volatile long optsarg) { struct fs_image_segment* segs = (struct fs_image_segment*)segments; int res = -1, err = 0, loopfd = -1, memfd = -1, need_loop_device = !!segs; char* mount_opts = (char*)optsarg; char* target = (char*)dir; char* fs = (char*)fsarg; char* source = NULL; char loopname[64]; if (need_loop_device) { memset(loopname, 0, sizeof(loopname)); snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid); if (setup_loop_device(size, nsegs, segs, loopname, &memfd, &loopfd) == -1) return -1; source = loopname; } mkdir(target, 0777); char opts[256]; memset(opts, 0, sizeof(opts)); if (strlen(mount_opts) > (sizeof(opts) - 32)) { } strncpy(opts, mount_opts, sizeof(opts) - 32); if (strcmp(fs, "iso9660") == 0) { flags |= MS_RDONLY; } else if (strncmp(fs, "ext", 3) == 0) { if (strstr(opts, "errors=panic") || strstr(opts, "errors=remount-ro") == 0) strcat(opts, ",errors=continue"); } else if (strcmp(fs, "xfs") == 0) { strcat(opts, ",nouuid"); } res = mount(source, target, fs, flags, opts); if (res == -1) { err = errno; goto error_clear_loop; } res = open(target, O_RDONLY | O_DIRECTORY); if (res == -1) { err = errno; } error_clear_loop: if (need_loop_device) { ioctl(loopfd, LOOP_CLR_FD, 0); close(loopfd); close(memfd); } errno = err; return res; } 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); 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 (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) { } 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_wifi_devices(); loop(); exit(1); } static void setup_binfmt_misc() { if (mount(0, "/proc/sys/fs/binfmt_misc", "binfmt_misc", 0, 0)) { } write_file("/proc/sys/fs/binfmt_misc/register", ":syz0:M:0:\x01::./file0:"); write_file("/proc/sys/fs/binfmt_misc/register", ":syz1:M:1:\x02::./file0:POC"); } static void setup_sysctl() { static struct { const char* name; const char* data; } files[] = { {"/sys/kernel/debug/x86/nmi_longest_ns", "10000000000"}, {"/proc/sys/kernel/hung_task_check_interval_secs", "20"}, {"/proc/sys/net/core/bpf_jit_enable", "1"}, {"/proc/sys/net/core/bpf_jit_kallsyms", "1"}, {"/proc/sys/net/core/bpf_jit_harden", "0"}, {"/proc/sys/kernel/kptr_restrict", "0"}, {"/proc/sys/kernel/softlockup_all_cpu_backtrace", "1"}, {"/proc/sys/fs/mount-max", "100"}, {"/proc/sys/vm/oom_dump_tasks", "0"}, {"/proc/sys/debug/exception-trace", "0"}, {"/proc/sys/kernel/printk", "7 4 1 3"}, {"/proc/sys/net/ipv4/ping_group_range", "0 65535"}, {"/proc/sys/kernel/keys/gc_delay", "1"}, {"/proc/sys/vm/nr_overcommit_hugepages", "4"}, {"/proc/sys/vm/oom_kill_allocating_task", "1"}, }; for (size_t i = 0; i < sizeof(files) / sizeof(files[0]); i++) { if (!write_file(files[i].name, files[i].data)) printf("write to %s failed: %s\n", files[i].name, strerror(errno)); } } void loop(void) { memcpy((void*)0x20000000, "bfs\000", 4); memcpy((void*)0x20000100, "./file0\000", 8); *(uint64_t*)0x20000200 = 0x20010000; memcpy((void*)0x20010000, "\xce\xfa\xad\x1b\x00\x82\x00\x00\x00\x82\x00\x00\xff\xff\xff\xff\xff" "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\x73\x79\x7a\x6b\x61\x6c" "\x73\x79\x7a\x6b\x61\x6c\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 64); *(uint64_t*)0x20000208 = 0x40; *(uint64_t*)0x20000210 = 0; *(uint64_t*)0x20000218 = 0; *(uint64_t*)0x20000220 = 0; *(uint64_t*)0x20000228 = 0x200; *(uint64_t*)0x20000230 = 0; *(uint64_t*)0x20000238 = 0; *(uint64_t*)0x20000240 = 0x8200; *(uint8_t*)0x20010300 = 0; syz_mount_image(0x20000000, 0x20000100, 0x8220, 3, 0x20000200, 0, 0x20010300); } int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); setup_sysctl(); setup_binfmt_misc(); do_sandbox_none(); return 0; }