/* * Copyright (C) 2008 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "util.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INIT_FULL_SOURCES #include #include #include "reboot_utils.h" #include "selabel.h" #include "selinux.h" #else #include "host_init_stubs.h" #endif using android::base::boot_clock; using android::base::StartsWith; using namespace std::literals::string_literals; namespace android { namespace init { const std::string kDefaultAndroidDtDir("/proc/device-tree/firmware/android/"); void (*trigger_shutdown)(const std::string& command) = nullptr; // DecodeUid() - decodes and returns the given string, which can be either the // numeric or name representation, into the integer uid or gid. Result DecodeUid(const std::string& name) { if (isalpha(name[0])) { passwd* pwd = getpwnam(name.c_str()); if (!pwd) return ErrnoError() << "getpwnam failed"; return pwd->pw_uid; } errno = 0; uid_t result = static_cast(strtoul(name.c_str(), 0, 0)); if (errno) return ErrnoError() << "strtoul failed"; return result; } /* * CreateSocket - creates a Unix domain socket in ANDROID_SOCKET_DIR * ("/dev/socket") as dictated in init.rc. This socket is inherited by the * daemon. We communicate the file descriptor's value via the environment * variable ANDROID_SOCKET_ENV_PREFIX ("ANDROID_SOCKET_foo"). */ Result CreateSocket(const std::string& name, int type, bool passcred, mode_t perm, uid_t uid, gid_t gid, const std::string& socketcon) { if (!socketcon.empty()) { if (setsockcreatecon(socketcon.c_str()) == -1) { return ErrnoError() << "setsockcreatecon(\"" << socketcon << "\") failed"; } } android::base::unique_fd fd(socket(PF_UNIX, type, 0)); if (fd < 0) { return ErrnoError() << "Failed to open socket '" << name << "'"; } if (!socketcon.empty()) setsockcreatecon(nullptr); struct sockaddr_un addr; memset(&addr, 0 , sizeof(addr)); addr.sun_family = AF_UNIX; snprintf(addr.sun_path, sizeof(addr.sun_path), ANDROID_SOCKET_DIR "/%s", name.c_str()); if ((unlink(addr.sun_path) != 0) && (errno != ENOENT)) { return ErrnoError() << "Failed to unlink old socket '" << name << "'"; } std::string secontext; if (SelabelLookupFileContext(addr.sun_path, S_IFSOCK, &secontext) && !secontext.empty()) { setfscreatecon(secontext.c_str()); } if (passcred) { int on = 1; if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) { return ErrnoError() << "Failed to set SO_PASSCRED '" << name << "'"; } } int ret = bind(fd, (struct sockaddr *) &addr, sizeof (addr)); int savederrno = errno; if (!secontext.empty()) { setfscreatecon(nullptr); } auto guard = android::base::make_scope_guard([&addr] { unlink(addr.sun_path); }); if (ret) { errno = savederrno; return ErrnoError() << "Failed to bind socket '" << name << "'"; } if (lchown(addr.sun_path, uid, gid)) { return ErrnoError() << "Failed to lchown socket '" << addr.sun_path << "'"; } if (fchmodat(AT_FDCWD, addr.sun_path, perm, AT_SYMLINK_NOFOLLOW)) { return ErrnoError() << "Failed to fchmodat socket '" << addr.sun_path << "'"; } LOG(INFO) << "Created socket '" << addr.sun_path << "'" << ", mode " << std::oct << perm << std::dec << ", user " << uid << ", group " << gid; guard.Disable(); return fd.release(); } Result ReadFile(const std::string& path) { android::base::unique_fd fd( TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC))); if (fd == -1) { return ErrnoError() << "open() failed"; } // For security reasons, disallow world-writable // or group-writable files. struct stat sb; if (fstat(fd, &sb) == -1) { return ErrnoError() << "fstat failed()"; } if ((sb.st_mode & (S_IWGRP | S_IWOTH)) != 0) { return Error() << "Skipping insecure file"; } std::string content; if (!android::base::ReadFdToString(fd, &content)) { return ErrnoError() << "Unable to read file contents"; } return content; } static int OpenFile(const std::string& path, int flags, mode_t mode) { std::string secontext; if (SelabelLookupFileContext(path, mode, &secontext) && !secontext.empty()) { setfscreatecon(secontext.c_str()); } int rc = open(path.c_str(), flags, mode); if (!secontext.empty()) { int save_errno = errno; setfscreatecon(nullptr); errno = save_errno; } return rc; } Result WriteFile(const std::string& path, const std::string& content) { android::base::unique_fd fd(TEMP_FAILURE_RETRY( OpenFile(path, O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC | O_CLOEXEC, 0600))); if (fd == -1) { return ErrnoError() << "open() failed"; } if (!android::base::WriteStringToFd(content, fd)) { return ErrnoError() << "Unable to write file contents"; } return {}; } bool mkdir_recursive(const std::string& path, mode_t mode) { std::string::size_type slash = 0; while ((slash = path.find('/', slash + 1)) != std::string::npos) { auto directory = path.substr(0, slash); struct stat info; if (stat(directory.c_str(), &info) != 0) { auto ret = make_dir(directory, mode); if (!ret && errno != EEXIST) return false; } } auto ret = make_dir(path, mode); if (!ret && errno != EEXIST) return false; return true; } int wait_for_file(const char* filename, std::chrono::nanoseconds timeout) { android::base::Timer t; while (t.duration() < timeout) { struct stat sb; if (stat(filename, &sb) != -1) { LOG(INFO) << "wait for '" << filename << "' took " << t; return 0; } std::this_thread::sleep_for(10ms); } LOG(WARNING) << "wait for '" << filename << "' timed out and took " << t; return -1; } void ImportKernelCmdline(const std::function& fn) { std::string cmdline; android::base::ReadFileToString("/proc/cmdline", &cmdline); for (const auto& entry : android::base::Split(android::base::Trim(cmdline), " ")) { std::vector pieces = android::base::Split(entry, "="); if (pieces.size() == 2) { fn(pieces[0], pieces[1]); } } } void ImportBootconfig(const std::function& fn) { std::string bootconfig; android::base::ReadFileToString("/proc/bootconfig", &bootconfig); for (const auto& entry : android::base::Split(bootconfig, "\n")) { std::vector pieces = android::base::Split(entry, "="); if (pieces.size() == 2) { // get rid of the extra space between a list of values and remove the quotes. std::string value = android::base::StringReplace(pieces[1], "\", \"", ",", true); value.erase(std::remove(value.begin(), value.end(), '"'), value.end()); fn(android::base::Trim(pieces[0]), android::base::Trim(value)); } } } bool make_dir(const std::string& path, mode_t mode) { std::string secontext; if (SelabelLookupFileContext(path, mode, &secontext) && !secontext.empty()) { setfscreatecon(secontext.c_str()); } int rc = mkdir(path.c_str(), mode); if (!secontext.empty()) { int save_errno = errno; setfscreatecon(nullptr); errno = save_errno; } return rc == 0; } /* * Returns true is pathname is a directory */ bool is_dir(const char* pathname) { struct stat info; if (stat(pathname, &info) == -1) { return false; } return S_ISDIR(info.st_mode); } Result ExpandProps(const std::string& src) { const char* src_ptr = src.c_str(); std::string dst; /* - variables can either be $x.y or ${x.y}, in case they are only part * of the string. * - will accept $$ as a literal $. * - no nested property expansion, i.e. ${foo.${bar}} is not supported, * bad things will happen * - ${x.y:-default} will return default value if property empty. */ while (*src_ptr) { const char* c; c = strchr(src_ptr, '$'); if (!c) { dst.append(src_ptr); return dst; } dst.append(src_ptr, c); c++; if (*c == '$') { dst.push_back(*(c++)); src_ptr = c; continue; } else if (*c == '\0') { return dst; } std::string prop_name; std::string def_val; if (*c == '{') { c++; const char* end = strchr(c, '}'); if (!end) { // failed to find closing brace, abort. return Error() << "unexpected end of string in '" << src << "', looking for }"; } prop_name = std::string(c, end); c = end + 1; size_t def = prop_name.find(":-"); if (def < prop_name.size()) { def_val = prop_name.substr(def + 2); prop_name = prop_name.substr(0, def); } } else { prop_name = c; if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_R__) { return Error() << "using deprecated syntax for specifying property '" << c << "', use ${name} instead"; } else { LOG(ERROR) << "using deprecated syntax for specifying property '" << c << "', use ${name} instead"; } c += prop_name.size(); } if (prop_name.empty()) { return Error() << "invalid zero-length property name in '" << src << "'"; } std::string prop_val = android::base::GetProperty(prop_name, ""); if (prop_val.empty()) { if (def_val.empty()) { return Error() << "property '" << prop_name << "' doesn't exist while expanding '" << src << "'"; } prop_val = def_val; } dst.append(prop_val); src_ptr = c; } return dst; } static std::string init_android_dt_dir() { // Use the standard procfs-based path by default std::string android_dt_dir = kDefaultAndroidDtDir; // The platform may specify a custom Android DT path in kernel cmdline ImportKernelCmdline([&](const std::string& key, const std::string& value) { if (key == "androidboot.android_dt_dir") { android_dt_dir = value; } }); // ..Or bootconfig if (android_dt_dir == kDefaultAndroidDtDir) { ImportBootconfig([&](const std::string& key, const std::string& value) { if (key == "androidboot.android_dt_dir") { android_dt_dir = value; } }); } LOG(INFO) << "Using Android DT directory " << android_dt_dir; return android_dt_dir; } // FIXME: The same logic is duplicated in system/core/fs_mgr/ const std::string& get_android_dt_dir() { // Set once and saves time for subsequent calls to this function static const std::string kAndroidDtDir = init_android_dt_dir(); return kAndroidDtDir; } // Reads the content of device tree file under the platform's Android DT directory. // Returns true if the read is success, false otherwise. bool read_android_dt_file(const std::string& sub_path, std::string* dt_content) { const std::string file_name = get_android_dt_dir() + sub_path; if (android::base::ReadFileToString(file_name, dt_content)) { if (!dt_content->empty()) { dt_content->pop_back(); // Trims the trailing '\0' out. return true; } } return false; } bool is_android_dt_value_expected(const std::string& sub_path, const std::string& expected_content) { std::string dt_content; if (read_android_dt_file(sub_path, &dt_content)) { if (dt_content == expected_content) { return true; } } return false; } bool IsLegalPropertyName(const std::string& name) { size_t namelen = name.size(); if (namelen < 1) return false; if (name[0] == '.') return false; if (name[namelen - 1] == '.') return false; /* Only allow alphanumeric, plus '.', '-', '@', ':', or '_' */ /* Don't allow ".." to appear in a property name */ for (size_t i = 0; i < namelen; i++) { if (name[i] == '.') { // i=0 is guaranteed to never have a dot. See above. if (name[i - 1] == '.') return false; continue; } if (name[i] == '_' || name[i] == '-' || name[i] == '@' || name[i] == ':') continue; if (name[i] >= 'a' && name[i] <= 'z') continue; if (name[i] >= 'A' && name[i] <= 'Z') continue; if (name[i] >= '0' && name[i] <= '9') continue; return false; } return true; } Result IsLegalPropertyValue(const std::string& name, const std::string& value) { if (value.size() >= PROP_VALUE_MAX && !StartsWith(name, "ro.")) { return Error() << "Property value too long"; } if (mbstowcs(nullptr, value.data(), 0) == static_cast(-1)) { return Error() << "Value is not a UTF8 encoded string"; } return {}; } static FscryptAction FscryptInferAction(const std::string& dir) { const std::string prefix = "/data/"; if (!android::base::StartsWith(dir, prefix)) { return FscryptAction::kNone; } // Special-case /data/media/obb per b/64566063 if (dir == "/data/media/obb") { // Try to set policy on this directory, but if it is non-empty this may fail. return FscryptAction::kAttempt; } // Only set policy on first level /data directories // To make this less restrictive, consider using a policy file. // However this is overkill for as long as the policy is simply // to apply a global policy to all /data folders created via makedir if (dir.find_first_of('/', prefix.size()) != std::string::npos) { return FscryptAction::kNone; } // Special case various directories that must not be encrypted, // often because their subdirectories must be encrypted. // This isn't a nice way to do this, see b/26641735 std::vector directories_to_exclude = { "lost+found", "system_ce", "system_de", "misc_ce", "misc_de", "vendor_ce", "vendor_de", "media", "data", "user", "user_de", "apex", "preloads", "app-staging", "gsi", }; for (const auto& d : directories_to_exclude) { if ((prefix + d) == dir) { return FscryptAction::kNone; } } // Empty these directories if policy setting fails. std::vector wipe_on_failure = { "rollback", "rollback-observer", // b/139193659 }; for (const auto& d : wipe_on_failure) { if ((prefix + d) == dir) { return FscryptAction::kDeleteIfNecessary; } } return FscryptAction::kRequire; } Result ParseMkdir(const std::vector& args) { mode_t mode = 0755; Result uid = -1; Result gid = -1; FscryptAction fscrypt_inferred_action = FscryptInferAction(args[1]); FscryptAction fscrypt_action = fscrypt_inferred_action; std::string ref_option = "ref"; bool set_option_encryption = false; bool set_option_key = false; for (size_t i = 2; i < args.size(); i++) { switch (i) { case 2: mode = std::strtoul(args[2].c_str(), 0, 8); break; case 3: uid = DecodeUid(args[3]); if (!uid.ok()) { return Error() << "Unable to decode UID for '" << args[3] << "': " << uid.error(); } break; case 4: gid = DecodeUid(args[4]); if (!gid.ok()) { return Error() << "Unable to decode GID for '" << args[4] << "': " << gid.error(); } break; default: auto parts = android::base::Split(args[i], "="); if (parts.size() != 2) { return Error() << "Can't parse option: '" << args[i] << "'"; } auto optname = parts[0]; auto optval = parts[1]; if (optname == "encryption") { if (set_option_encryption) { return Error() << "Duplicated option: '" << optname << "'"; } if (optval == "Require") { fscrypt_action = FscryptAction::kRequire; } else if (optval == "None") { fscrypt_action = FscryptAction::kNone; } else if (optval == "Attempt") { fscrypt_action = FscryptAction::kAttempt; } else if (optval == "DeleteIfNecessary") { fscrypt_action = FscryptAction::kDeleteIfNecessary; } else { return Error() << "Unknown encryption option: '" << optval << "'"; } set_option_encryption = true; } else if (optname == "key") { if (set_option_key) { return Error() << "Duplicated option: '" << optname << "'"; } if (optval == "ref" || optval == "per_boot_ref") { ref_option = optval; } else { return Error() << "Unknown key option: '" << optval << "'"; } set_option_key = true; } else { return Error() << "Unknown option: '" << args[i] << "'"; } } } if (set_option_key && fscrypt_action == FscryptAction::kNone) { return Error() << "Key option set but encryption action is none"; } const std::string prefix = "/data/"; if (StartsWith(args[1], prefix) && args[1].find_first_of('/', prefix.size()) == std::string::npos) { if (!set_option_encryption) { LOG(WARNING) << "Top-level directory needs encryption action, eg mkdir " << args[1] << " encryption=Require"; } if (fscrypt_action == FscryptAction::kNone) { LOG(INFO) << "Not setting encryption policy on: " << args[1]; } } if (fscrypt_action != fscrypt_inferred_action) { LOG(WARNING) << "Inferred action different from explicit one, expected " << static_cast(fscrypt_inferred_action) << " but got " << static_cast(fscrypt_action); } return MkdirOptions{args[1], mode, *uid, *gid, fscrypt_action, ref_option}; } Result ParseMountAll(const std::vector& args) { bool compat_mode = false; bool import_rc = false; if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) { if (args.size() <= 1) { return Error() << "mount_all requires at least 1 argument"; } compat_mode = true; import_rc = true; } std::size_t first_option_arg = args.size(); enum mount_mode mode = MOUNT_MODE_DEFAULT; // If we are <= Q, then stop looking for non-fstab arguments at slot 2. // Otherwise, stop looking at slot 1 (as the fstab path argument is optional >= R). for (std::size_t na = args.size() - 1; na > (compat_mode ? 1 : 0); --na) { if (args[na] == "--early") { first_option_arg = na; mode = MOUNT_MODE_EARLY; } else if (args[na] == "--late") { first_option_arg = na; mode = MOUNT_MODE_LATE; import_rc = false; } } std::string fstab_path; if (first_option_arg > 1) { fstab_path = args[1]; } else if (compat_mode) { return Error() << "mount_all argument 1 must be the fstab path"; } std::vector rc_paths; for (std::size_t na = 2; na < first_option_arg; ++na) { rc_paths.push_back(args[na]); } return MountAllOptions{rc_paths, fstab_path, mode, import_rc}; } Result>> ParseRestorecon( const std::vector& args) { struct flag_type { const char* name; int value; }; static const flag_type flags[] = { {"--recursive", SELINUX_ANDROID_RESTORECON_RECURSE}, {"--skip-ce", SELINUX_ANDROID_RESTORECON_SKIPCE}, {"--cross-filesystems", SELINUX_ANDROID_RESTORECON_CROSS_FILESYSTEMS}, {0, 0}}; int flag = 0; std::vector paths; bool in_flags = true; for (size_t i = 1; i < args.size(); ++i) { if (android::base::StartsWith(args[i], "--")) { if (!in_flags) { return Error() << "flags must precede paths"; } bool found = false; for (size_t j = 0; flags[j].name; ++j) { if (args[i] == flags[j].name) { flag |= flags[j].value; found = true; break; } } if (!found) { return Error() << "bad flag " << args[i]; } } else { in_flags = false; paths.emplace_back(args[i]); } } return std::pair(flag, paths); } Result ParseSwaponAll(const std::vector& args) { if (args.size() <= 1) { if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) { return Error() << "swapon_all requires at least 1 argument"; } return {}; } return args[1]; } Result ParseUmountAll(const std::vector& args) { if (args.size() <= 1) { if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) { return Error() << "umount_all requires at least 1 argument"; } return {}; } return args[1]; } static void InitAborter(const char* abort_message) { // When init forks, it continues to use this aborter for LOG(FATAL), but we want children to // simply abort instead of trying to reboot the system. if (getpid() != 1) { android::base::DefaultAborter(abort_message); return; } InitFatalReboot(SIGABRT); } // The kernel opens /dev/console and uses that fd for stdin/stdout/stderr if there is a serial // console enabled and no initramfs, otherwise it does not provide any fds for stdin/stdout/stderr. // SetStdioToDevNull() is used to close these existing fds if they exist and replace them with // /dev/null regardless. // // In the case that these fds are provided by the kernel, the exec of second stage init causes an // SELinux denial as it does not have access to /dev/console. In the case that they are not // provided, exec of any further process is potentially dangerous as the first fd's opened by that // process will take the stdin/stdout/stderr fileno's, which can cause issues if printf(), etc is // then used by that process. // // Lastly, simply calling SetStdioToDevNull() in first stage init is not enough, since first // stage init still runs in kernel context, future child processes will not have permissions to // access any fds that it opens, including the one opened below for /dev/null. Therefore, // SetStdioToDevNull() must be called again in second stage init. void SetStdioToDevNull(char** argv) { // Make stdin/stdout/stderr all point to /dev/null. int fd = open("/dev/null", O_RDWR); // NOLINT(android-cloexec-open) if (fd == -1) { int saved_errno = errno; android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter); errno = saved_errno; PLOG(FATAL) << "Couldn't open /dev/null"; } dup2(fd, STDIN_FILENO); dup2(fd, STDOUT_FILENO); dup2(fd, STDERR_FILENO); if (fd > STDERR_FILENO) close(fd); } void InitKernelLogging(char** argv) { SetFatalRebootTarget(); android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter); } bool IsRecoveryMode() { return access("/system/bin/recovery", F_OK) == 0; } // Check if default mount namespace is ready to be used with APEX modules static bool is_default_mount_namespace_ready = false; bool IsDefaultMountNamespaceReady() { return is_default_mount_namespace_ready; } void SetDefaultMountNamespaceReady() { is_default_mount_namespace_ready = true; } } // namespace init } // namespace android