// 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 static void sleep_ms(uint64_t ms) { usleep(ms * 1000); } static uint64_t current_time_ms(void) { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) exit(1); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } static void thread_start(void* (*fn)(void*), void* arg) { pthread_t th; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setstacksize(&attr, 128 << 10); int i = 0; for (; i < 100; i++) { if (pthread_create(&th, &attr, fn, arg) == 0) { pthread_attr_destroy(&attr); return; } if (errno == EAGAIN) { usleep(50); continue; } break; } exit(1); } typedef struct { int state; } event_t; static void event_init(event_t* ev) { ev->state = 0; } static void event_reset(event_t* ev) { ev->state = 0; } static void event_set(event_t* ev) { if (ev->state) exit(1); __atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE); syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000); } static void event_wait(event_t* ev) { while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0); } static int event_isset(event_t* ev) { return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE); } static int event_timedwait(event_t* ev, uint64_t timeout) { uint64_t start = current_time_ms(); uint64_t now = start; for (;;) { uint64_t remain = timeout - (now - start); struct timespec ts; ts.tv_sec = remain / 1000; ts.tv_nsec = (remain % 1000) * 1000 * 1000; syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts); if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) return 1; now = current_time_ms(); if (now - start > timeout) return 0; } } 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; } #define MAX_FDS 30 static void setup_gadgetfs(); static void setup_binderfs(); static void setup_fusectl(); static void sandbox_common_mount_tmpfs(void) { write_file("/proc/sys/fs/mount-max", "100000"); if (mkdir("./syz-tmp", 0777)) exit(1); if (mount("", "./syz-tmp", "tmpfs", 0, NULL)) exit(1); if (mkdir("./syz-tmp/newroot", 0777)) exit(1); if (mkdir("./syz-tmp/newroot/dev", 0700)) exit(1); unsigned bind_mount_flags = MS_BIND | MS_REC | MS_PRIVATE; if (mount("/dev", "./syz-tmp/newroot/dev", NULL, bind_mount_flags, NULL)) exit(1); if (mkdir("./syz-tmp/newroot/proc", 0700)) exit(1); if (mount("syz-proc", "./syz-tmp/newroot/proc", "proc", 0, NULL)) exit(1); if (mkdir("./syz-tmp/newroot/selinux", 0700)) exit(1); const char* selinux_path = "./syz-tmp/newroot/selinux"; if (mount("/selinux", selinux_path, NULL, bind_mount_flags, NULL)) { if (errno != ENOENT) exit(1); if (mount("/sys/fs/selinux", selinux_path, NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); } if (mkdir("./syz-tmp/newroot/sys", 0700)) exit(1); if (mount("/sys", "./syz-tmp/newroot/sys", 0, bind_mount_flags, NULL)) exit(1); if (mount("/sys/kernel/debug", "./syz-tmp/newroot/sys/kernel/debug", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mount("/sys/fs/smackfs", "./syz-tmp/newroot/sys/fs/smackfs", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mount("/proc/sys/fs/binfmt_misc", "./syz-tmp/newroot/proc/sys/fs/binfmt_misc", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mkdir("./syz-tmp/newroot/syz-inputs", 0700)) exit(1); if (mount("/syz-inputs", "./syz-tmp/newroot/syz-inputs", NULL, bind_mount_flags | MS_RDONLY, NULL) && errno != ENOENT) exit(1); if (mkdir("./syz-tmp/pivot", 0777)) exit(1); if (syscall(SYS_pivot_root, "./syz-tmp", "./syz-tmp/pivot")) { if (chdir("./syz-tmp")) exit(1); } else { if (chdir("/")) exit(1); if (umount2("./pivot", MNT_DETACH)) exit(1); } if (chroot("./newroot")) exit(1); if (chdir("/")) exit(1); setup_gadgetfs(); setup_binderfs(); setup_fusectl(); } static void setup_gadgetfs() { if (mkdir("/dev/gadgetfs", 0777)) { } if (mount("gadgetfs", "/dev/gadgetfs", "gadgetfs", 0, NULL)) { } } static void setup_fusectl() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) { } } static void setup_binderfs() { if (mkdir("/dev/binderfs", 0777)) { } if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) { } if (symlink("/dev/binderfs", "./binderfs")) { } } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); if (getppid() == 1) exit(1); 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 = 128 << 20; 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); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535"); sandbox_common_mount_tmpfs(); loop(); exit(1); } static void close_fds() { for (int fd = 3; fd < MAX_FDS; fd++) close(fd); } struct thread_t { int created, call; event_t ready, done; }; static struct thread_t threads[16]; static void execute_call(int call); static int running; static void* thr(void* arg) { struct thread_t* th = (struct thread_t*)arg; for (;;) { event_wait(&th->ready); event_reset(&th->ready); execute_call(th->call); __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED); event_set(&th->done); } return 0; } static void loop(void) { if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } int i, call, thread; for (call = 0; call < 6; call++) { for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0])); thread++) { struct thread_t* th = &threads[thread]; if (!th->created) { th->created = 1; event_init(&th->ready); event_init(&th->done); event_set(&th->done); thread_start(thr, th); } if (!event_isset(&th->done)) continue; event_reset(&th->done); th->call = call; __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED); event_set(&th->ready); event_timedwait(&th->done, 50); break; } } for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++) sleep_ms(1); close_fds(); } uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; void execute_call(int call) { intptr_t res = 0; switch (call) { case 0: // socketpair$unix arguments: [ // domain: const = 0x1 (8 bytes) // type: unix_socket_type = 0x3 (8 bytes) // proto: const = 0x0 (4 bytes) // fds: ptr[out, unix_pair] { // unix_pair { // fd0: sock_unix (resource) // fd1: sock_unix (resource) // } // } // ] res = syscall(__NR_socketpair, /*domain=*/1ul, /*type=SOCK_DGRAM|SOCK_STREAM*/ 3ul, /*proto=*/0, /*fds=*/0x200000000080ul); if (res != -1) { r[0] = *(uint32_t*)0x200000000080; r[1] = *(uint32_t*)0x200000000084; } break; case 1: // bind$unix arguments: [ // fd: sock_unix (resource) // addr: ptr[in, sockaddr_un] { // union sockaddr_un { // file: sockaddr_un_file { // family: unix_socket_family = 0x1 (2 bytes) // path: buffer: {2e 2f 66 69 6c 65 30 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00} (length 0x6c) // } // } // } // addrlen: len = 0x6e (8 bytes) // ] *(uint16_t*)0x200000000000 = 1; memcpy( (void*)0x200000000002, "./" "file0\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", 108); syscall(__NR_bind, /*fd=*/r[0], /*addr=*/0x200000000000ul, /*addrlen=*/0x6eul); break; case 2: // connect$unix arguments: [ // fd: sock_unix (resource) // addr: ptr[in, sockaddr_un] { // union sockaddr_un { // abs: sockaddr_un_abstract { // family: unix_socket_family = 0x0 (2 bytes) // ind: const = 0x0 (1 bytes) // pad = 0x0 (1 bytes) // id: int32 = 0x4e20 (4 bytes) // } // } // } // addrlen: len = 0x6e (8 bytes) // ] *(uint16_t*)0x2000000000c0 = 0; *(uint8_t*)0x2000000000c2 = 0; *(uint32_t*)0x2000000000c4 = 0x4e20; syscall(__NR_connect, /*fd=*/r[0], /*addr=*/0x2000000000c0ul, /*addrlen=*/0x6eul); break; case 3: // sendmmsg$unix arguments: [ // fd: sock_unix (resource) // mmsg: ptr[in, array[send_mmsghdr_un]] { // array[send_mmsghdr_un] { // } // } // vlen: len = 0x400000000000247 (8 bytes) // f: send_flags = 0x0 (8 bytes) // ] syscall(__NR_sendmmsg, /*fd=*/r[1], /*mmsg=*/0x2000000bd000ul, /*vlen=*/0x400000000000247ul, /*f=*/0ul); break; case 4: // socketpair$unix arguments: [ // domain: const = 0x1 (8 bytes) // type: unix_socket_type = 0x2 (8 bytes) // proto: const = 0x0 (4 bytes) // fds: ptr[out, unix_pair] { // unix_pair { // fd0: sock_unix (resource) // fd1: sock_unix (resource) // } // } // ] res = syscall(__NR_socketpair, /*domain=*/1ul, /*type=SOCK_DGRAM*/ 2ul, /*proto=*/0, /*fds=*/0x200000000200ul); if (res != -1) r[2] = *(uint32_t*)0x200000000204; break; case 5: // sendmmsg$unix arguments: [ // fd: sock_unix (resource) // mmsg: ptr[in, array[send_mmsghdr_un]] { // array[send_mmsghdr_un] { // send_mmsghdr_un { // msg_hdr: send_msghdr_un { // addr: nil // addrlen: len = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // vec: nil // vlen: len = 0x0 (8 bytes) // ctrl: nil // ctrllen: bytesize = 0x0 (8 bytes) // f: send_flags = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // } // msg_len: const = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // } // send_mmsghdr_un { // msg_hdr: send_msghdr_un { // addr: ptr[in, sockaddr_un] { // union sockaddr_un { // file: sockaddr_un_file { // family: unix_socket_family = 0x1 (2 bytes) // path: buffer: {2e 2f 66 69 6c 65 30 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00} // (length 0x6c) // } // } // } // addrlen: len = 0x6e (4 bytes) // pad = 0x0 (4 bytes) // vec: nil // vlen: len = 0x0 (8 bytes) // ctrl: nil // ctrllen: bytesize = 0x0 (8 bytes) // f: send_flags = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // } // msg_len: const = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // } // } // } // vlen: len = 0x2 (8 bytes) // f: send_flags = 0x0 (8 bytes) // ] *(uint64_t*)0x200000000ec0 = 0; *(uint32_t*)0x200000000ec8 = 0; *(uint64_t*)0x200000000ed0 = 0; *(uint64_t*)0x200000000ed8 = 0; *(uint64_t*)0x200000000ee0 = 0; *(uint64_t*)0x200000000ee8 = 0; *(uint32_t*)0x200000000ef0 = 0; *(uint32_t*)0x200000000ef8 = 0; *(uint64_t*)0x200000000f00 = 0x200000000300; *(uint16_t*)0x200000000300 = 1; memcpy( (void*)0x200000000302, "./" "file0\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000" "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", 108); *(uint32_t*)0x200000000f08 = 0x6e; *(uint64_t*)0x200000000f10 = 0; *(uint64_t*)0x200000000f18 = 0; *(uint64_t*)0x200000000f20 = 0; *(uint64_t*)0x200000000f28 = 0; *(uint32_t*)0x200000000f30 = 0; *(uint32_t*)0x200000000f38 = 0; syscall(__NR_sendmmsg, /*fd=*/r[2], /*mmsg=*/0x200000000ec0ul, /*vlen=*/2ul, /*f=*/0ul); break; } } int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000ul, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200001000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); const char* reason; (void)reason; do_sandbox_none(); return 0; }