| // Copyright (c) 2009-2010 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Contains the implementation of class Mount |
| |
| #include "mount.h" |
| |
| #include <errno.h> |
| |
| #include <base/file_util.h> |
| #include <base/logging.h> |
| #include <base/platform_thread.h> |
| #include <base/time.h> |
| #include <base/string_util.h> |
| #include <base/values.h> |
| #include <chromeos/utility.h> |
| #include <set> |
| |
| #include "crypto.h" |
| #include "cryptohome_common.h" |
| #include "old_vault_keyset.h" |
| #include "platform.h" |
| #include "username_passkey.h" |
| #include "vault_keyset.h" |
| #include "vault_keyset.pb.h" |
| |
| using std::string; |
| |
| namespace cryptohome { |
| |
| const std::string kDefaultHomeDir = "/home/chronos/user"; |
| const std::string kDefaultShadowRoot = "/home/.shadow"; |
| const std::string kDefaultSharedUser = "chronos"; |
| const std::string kDefaultSkeletonSource = "/etc/skel"; |
| // TODO(fes): Remove once UI for BWSI switches to MountGuest() |
| const std::string kIncognitoUser = "incognito"; |
| // The length of a user's directory name in the shadow root (equal to the length |
| // of the ascii version of a SHA1 hash) |
| const unsigned int kUserDirNameLength = 40; |
| // Encrypted files/directories in ecryptfs have file names that start with the |
| // following constant. When clearing tracked subdirectories, we ignore these |
| // and only delete the pass-through directories. |
| const std::string kEncryptedFilePrefix = "ECRYPTFS_FNEK_ENCRYPTED."; |
| // Tracked directories - special sub-directories of the cryptohome |
| // vault, that are visible even if not mounted. Contents is still encrypted. |
| const char* kCacheDir = "Cache"; |
| const char* kDownloadsDir = "Downloads"; |
| const struct TrackedDir { |
| const char* name; |
| bool need_migration; |
| } kTrackedDirs[] = { |
| {kCacheDir, false}, |
| {kDownloadsDir, true} |
| }; |
| |
| const std::string kDefaultEcryptfsCryptoAlg = "aes"; |
| const int kDefaultEcryptfsKeySize = CRYPTOHOME_AES_KEY_BYTES; |
| |
| Mount::Mount() |
| : default_user_(-1), |
| default_group_(-1), |
| default_username_(kDefaultSharedUser), |
| home_dir_(kDefaultHomeDir), |
| shadow_root_(kDefaultShadowRoot), |
| skel_source_(kDefaultSkeletonSource), |
| system_salt_(), |
| set_vault_ownership_(true), |
| default_crypto_(new Crypto()), |
| crypto_(default_crypto_.get()), |
| default_platform_(new Platform()), |
| platform_(default_platform_.get()), |
| fallback_to_scrypt_(true), |
| use_tpm_(true), |
| default_current_user_(new UserSession()), |
| current_user_(default_current_user_.get()) { |
| } |
| |
| Mount::~Mount() { |
| } |
| |
| bool Mount::Init() { |
| bool result = true; |
| |
| // Get the user id and group id of the default user |
| if (!platform_->GetUserId(default_username_, &default_user_, |
| &default_group_)) { |
| result = false; |
| } |
| |
| crypto_->set_use_tpm(use_tpm_); |
| crypto_->set_fallback_to_scrypt(fallback_to_scrypt_); |
| |
| int original_mask = platform_->SetMask(kDefaultUmask); |
| // Create the shadow root if it doesn't exist |
| FilePath shadow_root(shadow_root_); |
| if (!file_util::DirectoryExists(shadow_root)) { |
| file_util::CreateDirectory(shadow_root); |
| } |
| |
| if (!crypto_->Init()) { |
| result = false; |
| } |
| |
| // One-time load of the global system salt (used in generating username |
| // hashes) |
| FilePath system_salt_file(StringPrintf("%s/salt", shadow_root_.c_str())); |
| if (!crypto_->GetOrCreateSalt(system_salt_file, |
| CRYPTOHOME_DEFAULT_SALT_LENGTH, false, |
| &system_salt_)) { |
| LOG(ERROR) << "Failed to load or create the system salt"; |
| result = false; |
| } |
| platform_->SetMask(original_mask); |
| |
| current_user_->Init(crypto_, system_salt_); |
| |
| return result; |
| } |
| |
| bool Mount::EnsureCryptohome(const Credentials& credentials, |
| const Mount::MountArgs& mount_args, |
| bool* created) const { |
| // If the user has an old-style cryptohome, delete it |
| FilePath old_image_path(StringPrintf("%s/image", |
| GetUserDirectory(credentials).c_str())); |
| if (file_util::PathExists(old_image_path)) { |
| file_util::Delete(FilePath(GetUserDirectory(credentials)), true); |
| } |
| // Now check for the presence of a vault directory |
| FilePath vault_path(GetUserVaultPath(credentials)); |
| if (!file_util::DirectoryExists(vault_path)) { |
| // If the vault directory doesn't exist, then create the cryptohome from |
| // scratch |
| bool result = CreateCryptohome(credentials, mount_args); |
| if (created) { |
| *created = result; |
| } |
| return result; |
| } |
| if (created) { |
| *created = false; |
| } |
| return true; |
| } |
| |
| bool Mount::DoesCryptohomeExist(const Credentials& credentials) const { |
| // Check for the presence of a vault directory |
| FilePath vault_path(GetUserVaultPath(credentials)); |
| return file_util::DirectoryExists(vault_path); |
| } |
| |
| bool Mount::MountCryptohome(const Credentials& credentials, |
| const Mount::MountArgs& mount_args, |
| MountError* mount_error) const { |
| MountError local_mount_error = MOUNT_ERROR_NONE; |
| bool result = MountCryptohomeInner(credentials, |
| mount_args, |
| true, |
| &local_mount_error); |
| // Retry once if there is a TPM communications failure |
| if (!result && local_mount_error == MOUNT_ERROR_TPM_COMM_ERROR) { |
| result = MountCryptohomeInner(credentials, |
| mount_args, |
| true, |
| &local_mount_error); |
| } |
| if (mount_error) { |
| *mount_error = local_mount_error; |
| } |
| return result; |
| } |
| |
| bool Mount::MountCryptohomeInner(const Credentials& credentials, |
| const Mount::MountArgs& mount_args, |
| bool recreate_decrypt_fatal, |
| MountError* mount_error) const { |
| current_user_->Reset(); |
| |
| std::string username = credentials.GetFullUsernameString(); |
| if (username.compare(kIncognitoUser) == 0) { |
| // TODO(fes): Have guest set error conditions? |
| if (mount_error) { |
| *mount_error = MOUNT_ERROR_NONE; |
| } |
| return MountGuestCryptohome(); |
| } |
| |
| if (!mount_args.create_if_missing && !DoesCryptohomeExist(credentials)) { |
| if (mount_error) { |
| *mount_error = MOUNT_ERROR_USER_DOES_NOT_EXIST; |
| } |
| return false; |
| } |
| |
| bool created = false; |
| if (!EnsureCryptohome(credentials, mount_args, &created)) { |
| LOG(ERROR) << "Error creating cryptohome."; |
| if (mount_error) { |
| *mount_error = MOUNT_ERROR_FATAL; |
| } |
| return false; |
| } |
| |
| // Attempt to decrypt the vault keyset with the specified credentials |
| VaultKeyset vault_keyset; |
| SerializedVaultKeyset serialized; |
| MountError local_mount_error = MOUNT_ERROR_NONE; |
| if (!DecryptVaultKeyset(credentials, true, &vault_keyset, &serialized, |
| &local_mount_error)) { |
| if (mount_error) { |
| *mount_error = local_mount_error; |
| } |
| if (recreate_decrypt_fatal & (local_mount_error & MOUNT_ERROR_FATAL)) { |
| LOG(ERROR) << "Error, cryptohome must be re-created because of fatal " |
| << "error."; |
| if (!RemoveCryptohome(credentials)) { |
| LOG(ERROR) << "Fatal decryption error, but unable to remove " |
| << "cryptohome."; |
| return false; |
| } |
| // Allow one recursion into MountCryptohomeInner by blocking re-create on |
| // fatal. |
| bool local_result = MountCryptohomeInner(credentials, |
| mount_args, |
| false, |
| mount_error); |
| // If the mount was successful, set the status to indicate that the |
| // cryptohome was recreated. |
| if (local_result && mount_error) { |
| *mount_error = MOUNT_ERROR_RECREATED; |
| } |
| return local_result; |
| } |
| return false; |
| } |
| |
| crypto_->ClearKeyset(); |
| |
| // Add the decrypted key to the keyring so that ecryptfs can use it |
| string key_signature, fnek_signature; |
| if (!crypto_->AddKeyset(vault_keyset, &key_signature, &fnek_signature)) { |
| LOG(INFO) << "Cryptohome mount failed because of keyring failure."; |
| if (mount_error) { |
| *mount_error = MOUNT_ERROR_FATAL; |
| } |
| return false; |
| } |
| |
| // Specify the ecryptfs options for mounting the user's cryptohome |
| string ecryptfs_options = StringPrintf("ecryptfs_cipher=aes" |
| ",ecryptfs_key_bytes=%d" |
| ",ecryptfs_fnek_sig=%s" |
| ",ecryptfs_sig=%s" |
| ",ecryptfs_unlink_sigs", |
| kDefaultEcryptfsKeySize, |
| fnek_signature.c_str(), |
| key_signature.c_str()); |
| |
| // Mount cryptohome |
| string vault_path = GetUserVaultPath(credentials); |
| if (!platform_->Mount(vault_path, home_dir_, "ecryptfs", ecryptfs_options)) { |
| LOG(INFO) << "Cryptohome mount failed: " << errno << ", for vault: " |
| << vault_path; |
| if (mount_error) { |
| *mount_error = MOUNT_ERROR_FATAL; |
| } |
| return false; |
| } |
| |
| if (created) { |
| CopySkeletonForUser(credentials); |
| } |
| |
| // Ensure that the tracked subdirectories exist. |
| CreateTrackedSubdirectories(credentials, created); |
| |
| if (mount_error) { |
| *mount_error = MOUNT_ERROR_NONE; |
| } |
| |
| current_user_->SetUser(credentials); |
| return true; |
| } |
| |
| bool Mount::UnmountCryptohome() const { |
| current_user_->Reset(); |
| |
| // Try an immediate unmount |
| bool was_busy; |
| if (!platform_->Unmount(home_dir_, false, &was_busy)) { |
| LOG(ERROR) << "Couldn't unmount vault immediately, was_busy = " << was_busy; |
| if (was_busy) { |
| std::vector<ProcessInformation> processes; |
| platform_->GetProcessesWithOpenFiles(home_dir_, &processes); |
| for (std::vector<ProcessInformation>::iterator proc_itr = |
| processes.begin(); |
| proc_itr != processes.end(); |
| proc_itr++) { |
| LOG(ERROR) << "Process " << proc_itr->get_process_id() |
| << " had open files. Command line: " |
| << proc_itr->GetCommandLine(); |
| if (proc_itr->get_cwd().length()) { |
| LOG(ERROR) << " (" << proc_itr->get_process_id() << ") CWD: " |
| << proc_itr->get_cwd(); |
| } |
| for (std::set<std::string>::iterator file_itr = |
| proc_itr->get_open_files().begin(); |
| file_itr != proc_itr->get_open_files().end(); |
| file_itr++) { |
| LOG(ERROR) << " (" << proc_itr->get_process_id() << ") Open File: " |
| << (*file_itr); |
| } |
| } |
| sync(); |
| } |
| // Failed to unmount immediately, do a lazy unmount |
| platform_->Unmount(home_dir_, true, NULL); |
| sync(); |
| } |
| |
| // Clear the user keyring if the unmount was successful |
| crypto_->ClearKeyset(); |
| |
| return true; |
| } |
| |
| bool Mount::RemoveCryptohome(const Credentials& credentials) const { |
| std::string user_dir = GetUserDirectory(credentials); |
| CHECK(user_dir.length() > (shadow_root_.length() + 1)); |
| |
| if (IsCryptohomeMountedForUser(credentials)) { |
| if (!UnmountCryptohome()) { |
| return false; |
| } |
| } |
| |
| return file_util::Delete(FilePath(user_dir), true); |
| } |
| |
| bool Mount::IsCryptohomeMounted() const { |
| return platform_->IsDirectoryMounted(home_dir_); |
| } |
| |
| bool Mount::IsCryptohomeMountedForUser(const Credentials& credentials) const { |
| return platform_->IsDirectoryMountedWith(home_dir_, |
| GetUserVaultPath(credentials)); |
| } |
| |
| bool Mount::CreateCryptohome(const Credentials& credentials, |
| const Mount::MountArgs& mount_args) const { |
| int original_mask = platform_->SetMask(kDefaultUmask); |
| |
| // Create the user's entry in the shadow root |
| FilePath user_dir(GetUserDirectory(credentials)); |
| file_util::CreateDirectory(user_dir); |
| |
| // Generate a new master key |
| VaultKeyset vault_keyset; |
| vault_keyset.CreateRandom(*this); |
| SerializedVaultKeyset serialized; |
| if (!AddVaultKeyset(credentials, vault_keyset, &serialized)) { |
| platform_->SetMask(original_mask); |
| return false; |
| } |
| if (!StoreVaultKeyset(credentials, serialized)) { |
| platform_->SetMask(original_mask); |
| return false; |
| } |
| |
| // Create the user's path and set the proper ownership |
| std::string vault_path = GetUserVaultPath(credentials); |
| if (!file_util::CreateDirectory(FilePath(vault_path))) { |
| LOG(ERROR) << "Couldn't create vault path: " << vault_path.c_str(); |
| platform_->SetMask(original_mask); |
| return false; |
| } |
| if (set_vault_ownership_) { |
| if (!platform_->SetOwnership(vault_path, default_user_, default_group_)) { |
| LOG(ERROR) << "Couldn't change owner (" << default_user_ << ":" |
| << default_group_ << ") of vault path: " |
| << vault_path.c_str(); |
| platform_->SetMask(original_mask); |
| return false; |
| } |
| } |
| |
| // Restore the umask |
| platform_->SetMask(original_mask); |
| return true; |
| } |
| |
| bool Mount::CreateTrackedSubdirectories(const Credentials& credentials, |
| bool is_new) const { |
| const int original_mask = platform_->SetMask(kDefaultUmask); |
| |
| // Add the subdirectories if they do not exist. |
| const FilePath vault_path = FilePath(GetUserVaultPath(credentials)); |
| if (!file_util::DirectoryExists(vault_path)) { |
| LOG(ERROR) << "Can't create tracked subdirectories for a missing user."; |
| platform_->SetMask(original_mask); |
| return false; |
| } |
| |
| // The call is allowed to partially fail if directory creation fails, but we |
| // want to have as many of the specified tracked directories created as |
| // possible. |
| bool result = true; |
| for (size_t index = 0; index < arraysize(kTrackedDirs); ++index) { |
| const TrackedDir& subdir = kTrackedDirs[index]; |
| const string subdir_name = subdir.name; |
| const FilePath passthrough_dir = vault_path.Append(subdir_name); |
| const FilePath old_dir = FilePath(home_dir_).Append(subdir_name); |
| |
| // Start migrating if |subdir| is not a pass-through directory yet. |
| FilePath tmp_migrated_dir; |
| if (!is_new && file_util::DirectoryExists(old_dir) && |
| !file_util::DirectoryExists(passthrough_dir)) { |
| if (!subdir.need_migration) { |
| LOG(INFO) << "Removing non-pass-through " << old_dir.value() << ". " |
| << "Migration not requested."; |
| file_util::Delete(old_dir, true); |
| } else { |
| // Migrate it: rename it, and after the pass-through one is |
| // created, move its contents there. |
| tmp_migrated_dir = FilePath(home_dir_).Append(subdir_name + ".tmp"); |
| LOG(INFO) << "Moving migration directory " << old_dir.value() |
| << " to " << tmp_migrated_dir.value() << "..."; |
| if (!file_util::Move(old_dir, tmp_migrated_dir)) { |
| LOG(ERROR) << "Moving migration directory " << old_dir.value() |
| << " to " << tmp_migrated_dir.value() << " failed. " |
| << "Deleting it."; |
| file_util::Delete(old_dir, true); |
| tmp_migrated_dir.clear(); |
| result = false; |
| } |
| } |
| } |
| |
| // Create pass-through directory. |
| if (!file_util::DirectoryExists(passthrough_dir)) { |
| file_util::CreateDirectory(passthrough_dir); |
| if (set_vault_ownership_) { |
| if (!platform_->SetOwnership(passthrough_dir.value(), |
| default_user_, default_group_)) { |
| LOG(ERROR) << "Couldn't change owner (" << default_user_ << ":" |
| << default_group_ << ") of tracked directory path: " |
| << passthrough_dir.value(); |
| file_util::Delete(passthrough_dir, true); |
| result = false; |
| continue; |
| } |
| } |
| } |
| |
| // Finish migration if started for this directory. |
| if (!tmp_migrated_dir.empty()) { |
| const FilePath new_dir = FilePath(home_dir_).Append(subdir_name); |
| if (!file_util::DirectoryExists(new_dir)) { |
| LOG(ERROR) << "Unable to locate created pass-through directory from " |
| << new_dir.value() << ". Are we in a unit-test?"; |
| |
| // For the test sake (where we don't have real mount), just create it. |
| file_util::CreateDirectory(new_dir); |
| } |
| LOG(INFO) << "Moving migration directory " << tmp_migrated_dir.value() |
| << " to " << new_dir.value() << "..."; |
| if (!file_util::Move(tmp_migrated_dir, new_dir)) { |
| LOG(ERROR) << "Unable to move."; |
| result = false; |
| } |
| file_util::Delete(tmp_migrated_dir, true); |
| } |
| } |
| |
| // Restore the umask |
| platform_->SetMask(original_mask); |
| return result; |
| } |
| |
| void Mount::DoForEveryUnmountedCryptohome(CryptohomeCallback callback) const { |
| FilePath shadow_root(shadow_root_); |
| file_util::FileEnumerator dir_enumerator(shadow_root, false, |
| file_util::FileEnumerator::DIRECTORIES); |
| for (FilePath next_path = dir_enumerator.Next(); !next_path.empty(); |
| next_path = dir_enumerator.Next()) { |
| FilePath dir_name = next_path.BaseName(); |
| string str_dir_name = dir_name.value(); |
| if (str_dir_name.length() != kUserDirNameLength) { |
| continue; |
| } |
| bool valid_name = true; |
| for (string::const_iterator itr = str_dir_name.begin(); |
| itr < str_dir_name.end(); ++itr) { |
| if (!isxdigit(*itr)) { |
| valid_name = false; |
| break; |
| } |
| } |
| if (!valid_name) { |
| continue; |
| } |
| FilePath vault_path = next_path.Append("vault"); |
| if (!file_util::DirectoryExists(vault_path)) { |
| continue; |
| } |
| if (platform_->IsDirectoryMountedWith(home_dir_, vault_path.value())) { |
| continue; |
| } |
| callback(vault_path); |
| } |
| } |
| |
| // Deletes all tracking subdirectories of the given vault. |
| static void DeleteTrackedDirsCallback(const FilePath& vault) { |
| file_util::FileEnumerator subdir_enumerator( |
| vault, false, file_util::FileEnumerator::DIRECTORIES); |
| for (FilePath subdir_path = subdir_enumerator.Next(); !subdir_path.empty(); |
| subdir_path = subdir_enumerator.Next()) { |
| FilePath subdir_name = subdir_path.BaseName(); |
| if (subdir_name.value().find(kEncryptedFilePrefix) == 0) { |
| continue; |
| } |
| if (subdir_name.value().compare(".") == 0 || |
| subdir_name.value().compare("..") == 0) { |
| continue; |
| } |
| file_util::Delete(subdir_path, true); |
| } |
| } |
| |
| void Mount::CleanUnmountedTrackedSubdirectories() const { |
| DoForEveryUnmountedCryptohome(&DeleteTrackedDirsCallback); |
| } |
| |
| // Deletes Cache tracking directory of the given vault. |
| static void DeleteCacheCallback(const FilePath& vault) { |
| LOG(WARNING) << "Deleting Cache for user " << vault.value(); |
| file_util::Delete(vault.Append(kCacheDir), true); |
| } |
| |
| void Mount::DoAutomaticFreeDiskSpaceControl() const { |
| if (platform_->AmountOfFreeDiskSpace(home_dir_) > kMinFreeSpace) |
| return; |
| |
| // Clean Cache directories for every user (except current one). |
| DoForEveryUnmountedCryptohome(&DeleteCacheCallback); |
| |
| // TODO(glotov): do further cleanup. |
| } |
| |
| bool Mount::TestCredentials(const Credentials& credentials) const { |
| // If the current logged in user matches, use the UserSession to verify the |
| // credentials. This is less costly than a trip to the TPM, and only verifies |
| // a user during their logged in session. |
| if (current_user_->CheckUser(credentials)) { |
| return current_user_->Verify(credentials); |
| } |
| MountError mount_error; |
| VaultKeyset vault_keyset; |
| SerializedVaultKeyset serialized; |
| bool result = DecryptVaultKeyset(credentials, false, &vault_keyset, |
| &serialized, &mount_error); |
| // Retry once if there is a TPM communications failure |
| if (!result && mount_error == MOUNT_ERROR_TPM_COMM_ERROR) { |
| result = DecryptVaultKeyset(credentials, false, &vault_keyset, |
| &serialized, &mount_error); |
| } |
| return result; |
| } |
| |
| bool Mount::LoadVaultKeyset(const Credentials& credentials, |
| SerializedVaultKeyset* serialized) const { |
| // Load the encrypted keyset |
| FilePath user_key_file(GetUserKeyFile(credentials)); |
| if (!file_util::PathExists(user_key_file)) { |
| return false; |
| } |
| SecureBlob cipher_text; |
| if (!LoadFileBytes(user_key_file, &cipher_text)) { |
| return false; |
| } |
| if (!serialized->ParseFromArray( |
| static_cast<const unsigned char*>(cipher_text.data()), |
| cipher_text.size())) { |
| return false; |
| } |
| return true; |
| } |
| |
| bool Mount::StoreVaultKeyset(const Credentials& credentials, |
| const SerializedVaultKeyset& serialized) const { |
| SecureBlob final_blob(serialized.ByteSize()); |
| serialized.SerializeWithCachedSizesToArray( |
| static_cast<google::protobuf::uint8*>(final_blob.data())); |
| unsigned int data_written = file_util::WriteFile( |
| FilePath(GetUserKeyFile(credentials)), |
| static_cast<const char*>(final_blob.const_data()), |
| final_blob.size()); |
| |
| if (data_written != final_blob.size()) { |
| return false; |
| } |
| return true; |
| } |
| |
| bool Mount::DecryptVaultKeyset(const Credentials& credentials, |
| bool migrate_if_needed, |
| VaultKeyset* vault_keyset, |
| SerializedVaultKeyset* serialized, |
| MountError* error) const { |
| FilePath salt_path(GetUserSaltFile(credentials)); |
| // If a separate salt file exists, it is the old-style keyset |
| if (file_util::PathExists(salt_path)) { |
| VaultKeyset old_keyset; |
| if (!DecryptVaultKeysetOld(credentials, &old_keyset, error)) { |
| return false; |
| } |
| if (migrate_if_needed) { |
| // This is not considered a fatal error. Re-saving with the desired |
| // protection is ideal, but not required. |
| ReEncryptVaultKeyset(credentials, old_keyset, serialized); |
| } |
| vault_keyset->FromVaultKeyset(old_keyset); |
| return true; |
| } else { |
| SecureBlob passkey; |
| credentials.GetPasskey(&passkey); |
| |
| // Load the encrypted keyset |
| if (!LoadVaultKeyset(credentials, serialized)) { |
| if (error) { |
| *error = MOUNT_ERROR_FATAL; |
| } |
| return false; |
| } |
| |
| // Attempt decrypt the master key with the passkey |
| unsigned int crypt_flags = 0; |
| Crypto::CryptoError crypto_error = Crypto::CE_NONE; |
| if (!crypto_->DecryptVaultKeyset(*serialized, passkey, &crypt_flags, |
| &crypto_error, vault_keyset)) { |
| if (error) { |
| switch (crypto_error) { |
| case Crypto::CE_TPM_FATAL: |
| case Crypto::CE_OTHER_FATAL: |
| *error = Mount::MOUNT_ERROR_FATAL; |
| break; |
| case Crypto::CE_TPM_COMM_ERROR: |
| *error = Mount::MOUNT_ERROR_TPM_COMM_ERROR; |
| break; |
| case Crypto::CE_TPM_DEFEND_LOCK: |
| *error = Mount::MOUNT_ERROR_TPM_DEFEND_LOCK; |
| break; |
| default: |
| *error = Mount::MOUNT_ERROR_KEY_FAILURE; |
| break; |
| } |
| } |
| return false; |
| } |
| |
| if (migrate_if_needed) { |
| // Calling EnsureTpm here handles the case where a user logged in while |
| // cryptohome was taking TPM ownership. In that case, their vault keyset |
| // would be scrypt-wrapped and the TPM would not be connected. If we're |
| // configured to use the TPM, calling EnsureTpm will try to connect, and |
| // if successful, the call to has_tpm() below will succeed, allowing |
| // re-wrapping (migration) using the TPM. |
| if (use_tpm_) { |
| crypto_->EnsureTpm(false); |
| } |
| |
| // If the vault keyset's TPM state is not the same as that configured for |
| // the device, re-save the keyset (this will save in the device's default |
| // method). |
| // 1 2 3 4 5 6 7 8 9 10 11 12 |
| // use_tpm - - - X X X X X X - - - |
| // |
| // fallback_to_scrypt - - - - - - X X X X X X |
| // |
| // tpm_wrapped - X - - X - - X - - X - |
| // |
| // scrypt_wrapped - - X - - X - - X - - X |
| // |
| // migrate N Y Y Y N Y Y N Y Y Y N |
| bool tpm_wrapped = |
| (crypt_flags & SerializedVaultKeyset::TPM_WRAPPED) != 0; |
| bool scrypt_wrapped = |
| (crypt_flags & SerializedVaultKeyset::SCRYPT_WRAPPED) != 0; |
| bool should_tpm = (crypto_->has_tpm() && use_tpm_ && |
| crypto_->is_tpm_connected()); |
| bool should_scrypt = fallback_to_scrypt_; |
| do { |
| // If the keyset was TPM-wrapped, but there was no public key hash, |
| // always re-save. Otherwise, check the table. |
| if (crypto_error != Crypto::CE_NO_PUBLIC_KEY_HASH) { |
| if (tpm_wrapped && should_tpm) |
| break; // 5, 8 |
| if (scrypt_wrapped && should_scrypt && !should_tpm) |
| break; // 12 |
| if (!tpm_wrapped && !scrypt_wrapped && !should_tpm && !should_scrypt) |
| break; // 1 |
| } |
| // This is not considered a fatal error. Re-saving with the desired |
| // protection is ideal, but not required. |
| SerializedVaultKeyset new_serialized; |
| new_serialized.CopyFrom(*serialized); |
| if (ReEncryptVaultKeyset(credentials, *vault_keyset, &new_serialized)) { |
| serialized->CopyFrom(new_serialized); |
| } |
| } while(false); |
| } |
| |
| return true; |
| } |
| } |
| |
| bool Mount::AddVaultKeyset(const Credentials& credentials, |
| const VaultKeyset& vault_keyset, |
| SerializedVaultKeyset* serialized) const { |
| // We don't do passkey to wrapper conversion because it is salted during save |
| SecureBlob passkey; |
| credentials.GetPasskey(&passkey); |
| |
| // Encrypt the vault keyset |
| SecureBlob salt(CRYPTOHOME_DEFAULT_KEY_SALT_SIZE); |
| crypto_->GetSecureRandom(static_cast<unsigned char*>(salt.data()), |
| salt.size()); |
| |
| if (!crypto_->EncryptVaultKeyset(vault_keyset, passkey, salt, serialized)) { |
| LOG(ERROR) << "Encrypting vault keyset failed"; |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool Mount::ReEncryptVaultKeyset(const Credentials& credentials, |
| const VaultKeyset& vault_keyset, |
| SerializedVaultKeyset* serialized) const { |
| std::vector<std::string> files(2); |
| files[0] = GetUserSaltFile(credentials); |
| files[1] = GetUserKeyFile(credentials); |
| if (!CacheOldFiles(credentials, files)) { |
| LOG(ERROR) << "Couldn't cache old key material."; |
| return false; |
| } |
| if (!AddVaultKeyset(credentials, vault_keyset, serialized)) { |
| LOG(ERROR) << "Couldn't add keyset."; |
| RevertCacheFiles(credentials, files); |
| return false; |
| } |
| if (!StoreVaultKeyset(credentials, *serialized)) { |
| LOG(ERROR) << "Write to master key failed"; |
| RevertCacheFiles(credentials, files); |
| return false; |
| } |
| DeleteCacheFiles(credentials, files); |
| return true; |
| } |
| |
| bool Mount::MigratePasskey(const Credentials& credentials, |
| const char* old_key) const { |
| |
| std::string username = credentials.GetFullUsernameString(); |
| UsernamePasskey old_credentials(username.c_str(), |
| SecureBlob(old_key, strlen(old_key))); |
| // Attempt to decrypt the vault keyset with the specified credentials |
| MountError mount_error; |
| VaultKeyset vault_keyset; |
| SerializedVaultKeyset serialized; |
| bool result = DecryptVaultKeyset(old_credentials, false, &vault_keyset, |
| &serialized, &mount_error); |
| // Retry once if there is a TPM communications failure |
| if (!result && mount_error == MOUNT_ERROR_TPM_COMM_ERROR) { |
| result = DecryptVaultKeyset(old_credentials, false, &vault_keyset, |
| &serialized, &mount_error); |
| } |
| if (result) { |
| if (!ReEncryptVaultKeyset(credentials, vault_keyset, &serialized)) { |
| LOG(ERROR) << "Couldn't save keyset."; |
| current_user_->Reset(); |
| return false; |
| } |
| current_user_->SetUser(credentials); |
| return true; |
| } |
| current_user_->Reset(); |
| return false; |
| } |
| |
| bool Mount::MountGuestCryptohome() const { |
| current_user_->Reset(); |
| |
| // Attempt to mount guestfs |
| if (!platform_->Mount("guestfs", home_dir_, "tmpfs", "")) { |
| LOG(ERROR) << "Cryptohome mount failed: " << errno << " for guestfs"; |
| return false; |
| } |
| if (set_vault_ownership_) { |
| if (!platform_->SetOwnership(home_dir_, default_user_, default_group_)) { |
| LOG(ERROR) << "Couldn't change owner (" << default_user_ << ":" |
| << default_group_ << ") of guestfs path: " |
| << home_dir_.c_str(); |
| bool was_busy; |
| platform_->Unmount(home_dir_.c_str(), false, &was_busy); |
| return false; |
| } |
| } |
| CopySkeleton(); |
| return true; |
| } |
| |
| string Mount::GetUserDirectory(const Credentials& credentials) const { |
| return StringPrintf("%s/%s", |
| shadow_root_.c_str(), |
| credentials.GetObfuscatedUsername(system_salt_).c_str()); |
| } |
| |
| string Mount::GetUserSaltFile(const Credentials& credentials) const { |
| return StringPrintf("%s/%s/master.0.salt", |
| shadow_root_.c_str(), |
| credentials.GetObfuscatedUsername(system_salt_).c_str()); |
| } |
| |
| string Mount::GetUserKeyFile(const Credentials& credentials) const { |
| return StringPrintf("%s/%s/master.0", |
| shadow_root_.c_str(), |
| credentials.GetObfuscatedUsername(system_salt_).c_str()); |
| } |
| |
| string Mount::GetUserVaultPath(const Credentials& credentials) const { |
| return StringPrintf("%s/%s/vault", |
| shadow_root_.c_str(), |
| credentials.GetObfuscatedUsername(system_salt_).c_str()); |
| } |
| |
| void Mount::RecursiveCopy(const FilePath& destination, |
| const FilePath& source) const { |
| file_util::FileEnumerator file_enumerator(source, false, |
| file_util::FileEnumerator::FILES); |
| FilePath next_path; |
| while (!(next_path = file_enumerator.Next()).empty()) { |
| FilePath file_name = next_path.BaseName(); |
| FilePath destination_file = destination.Append(file_name); |
| file_util::CopyFile(next_path, destination_file); |
| if (set_vault_ownership_) { |
| if (chown(destination_file.value().c_str(), default_user_, |
| default_group_)) { |
| LOG(ERROR) << "Couldn't change owner (" << default_user_ << ":" |
| << default_group_ << ") of skeleton path: " |
| << destination_file.value().c_str(); |
| } |
| } |
| } |
| file_util::FileEnumerator dir_enumerator(source, false, |
| file_util::FileEnumerator::DIRECTORIES); |
| while (!(next_path = dir_enumerator.Next()).empty()) { |
| FilePath dir_name = next_path.BaseName(); |
| FilePath destination_dir = destination.Append(dir_name); |
| file_util::CreateDirectory(destination_dir); |
| if (set_vault_ownership_) { |
| if (chown(destination_dir.value().c_str(), default_user_, |
| default_group_)) { |
| LOG(ERROR) << "Couldn't change owner (" << default_user_ << ":" |
| << default_group_ << ") of skeleton path: " |
| << destination_dir.value().c_str(); |
| } |
| } |
| RecursiveCopy(destination_dir, next_path); |
| } |
| } |
| |
| void Mount::CopySkeletonForUser(const Credentials& credentials) const { |
| if (IsCryptohomeMountedForUser(credentials)) { |
| CopySkeleton(); |
| } |
| } |
| |
| void Mount::CopySkeleton() const { |
| RecursiveCopy(FilePath(home_dir_), FilePath(skel_source_)); |
| } |
| |
| void Mount::GetSecureRandom(unsigned char *rand, unsigned int length) const { |
| crypto_->GetSecureRandom(rand, length); |
| } |
| |
| bool Mount::RemoveOldFiles(const Credentials& credentials) const { |
| FilePath key_file(GetUserKeyFile(credentials)); |
| if (file_util::PathExists(key_file)) { |
| if (!file_util::Delete(key_file, false)) { |
| return false; |
| } |
| } |
| FilePath salt_file(GetUserSaltFile(credentials)); |
| if (file_util::PathExists(salt_file)) { |
| if (!file_util::Delete(salt_file, false)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| bool Mount::CacheOldFiles(const Credentials& credentials, |
| std::vector<std::string>& files) const { |
| for (unsigned int index = 0; index < files.size(); ++index) { |
| FilePath file(files[index]); |
| FilePath file_bak(StringPrintf("%s.bak", files[index].c_str())); |
| if (file_util::PathExists(file_bak)) { |
| if (!file_util::Delete(file_bak, false)) { |
| return false; |
| } |
| } |
| if (file_util::PathExists(file)) { |
| if (!file_util::Move(file, file_bak)) { |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool Mount::RevertCacheFiles(const Credentials& credentials, |
| std::vector<std::string>& files) const { |
| for (unsigned int index = 0; index < files.size(); ++index) { |
| FilePath file(files[index]); |
| FilePath file_bak(StringPrintf("%s.bak", files[index].c_str())); |
| if (file_util::PathExists(file_bak)) { |
| if (!file_util::Move(file_bak, file)) { |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool Mount::DeleteCacheFiles(const Credentials& credentials, |
| std::vector<std::string>& files) const { |
| for (unsigned int index = 0; index < files.size(); ++index) { |
| FilePath file(files[index]); |
| FilePath file_bak(StringPrintf("%s.bak", files[index].c_str())); |
| if (file_util::PathExists(file_bak)) { |
| if (!file_util::Delete(file_bak, false)) { |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| void Mount::GetSystemSalt(chromeos::Blob* salt) const { |
| *salt = system_salt_; |
| } |
| |
| void Mount::GetUserSalt(const Credentials& credentials, bool force, |
| SecureBlob* salt) const { |
| FilePath path(GetUserSaltFile(credentials)); |
| crypto_->GetOrCreateSalt(path, CRYPTOHOME_DEFAULT_SALT_LENGTH, force, salt); |
| } |
| |
| bool Mount::LoadFileBytes(const FilePath& path, |
| SecureBlob* blob) { |
| int64 file_size; |
| if (!file_util::PathExists(path)) { |
| return false; |
| } |
| if (!file_util::GetFileSize(path, &file_size)) { |
| LOG(ERROR) << "Could not get size of " << path.value(); |
| return false; |
| } |
| // Compare to the max of a 32-bit signed integer |
| if (file_size > static_cast<int64>(INT_MAX)) { |
| LOG(ERROR) << "File " << path.value() << " is too large: " << file_size; |
| return false; |
| } |
| SecureBlob buf(file_size); |
| int data_read = file_util::ReadFile(path, reinterpret_cast<char*>(&buf[0]), |
| file_size); |
| // Cast is okay because of comparison to INT_MAX above |
| if (data_read != static_cast<int>(file_size)) { |
| LOG(ERROR) << "Could not read entire file " << file_size; |
| return false; |
| } |
| blob->swap(buf); |
| return true; |
| } |
| |
| bool Mount::LoadFileString(const FilePath& path, |
| std::string* content) { |
| if (!file_util::PathExists(path)) { |
| return false; |
| } |
| |
| if (!file_util::ReadFileToString(path, content)) { |
| LOG(INFO) << "Could not read file contents: " << path.value(); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool Mount::SaveVaultKeysetOld(const Credentials& credentials, |
| const VaultKeyset& vault_keyset) const { |
| // Get the vault keyset key |
| SecureBlob user_salt; |
| GetUserSalt(credentials, true, &user_salt); |
| SecureBlob passkey; |
| credentials.GetPasskey(&passkey); |
| SecureBlob keyset_key; |
| crypto_->PasskeyToKeysetKey(passkey, user_salt, 1, &keyset_key); |
| |
| // Encrypt the vault keyset |
| SecureBlob salt(CRYPTOHOME_DEFAULT_KEY_SALT_SIZE); |
| SecureBlob cipher_text; |
| crypto_->GetSecureRandom(static_cast<unsigned char*>(salt.data()), |
| salt.size()); |
| if (!crypto_->EncryptVaultKeysetOld(vault_keyset, keyset_key, salt, |
| &cipher_text)) { |
| LOG(ERROR) << "Encrypting vault keyset failed"; |
| return false; |
| } |
| |
| // Save the master key |
| unsigned int data_written = file_util::WriteFile( |
| FilePath(GetUserKeyFile(credentials)), |
| static_cast<const char*>(cipher_text.const_data()), |
| cipher_text.size()); |
| |
| if (data_written != cipher_text.size()) { |
| LOG(ERROR) << "Write to master key failed"; |
| return false; |
| } |
| return true; |
| } |
| |
| bool Mount::DecryptVaultKeysetOld(const Credentials& credentials, |
| VaultKeyset* vault_keyset, |
| MountError* error) const { |
| // Generate the keyset key (key encryption key) |
| SecureBlob user_salt; |
| GetUserSalt(credentials, false, &user_salt); |
| if (user_salt.size() == 0) { |
| if (error) { |
| *error = MOUNT_ERROR_FATAL; |
| } |
| return false; |
| } |
| SecureBlob passkey; |
| credentials.GetPasskey(&passkey); |
| SecureBlob keyset_key; |
| crypto_->PasskeyToKeysetKey(passkey, user_salt, 1, &keyset_key); |
| |
| // Load the encrypted keyset |
| FilePath user_key_file(GetUserKeyFile(credentials)); |
| if (!file_util::PathExists(user_key_file)) { |
| if (error) { |
| *error = MOUNT_ERROR_FATAL; |
| } |
| return false; |
| } |
| SecureBlob cipher_text; |
| if (!LoadFileBytes(user_key_file, &cipher_text)) { |
| if (error) { |
| *error = MOUNT_ERROR_FATAL; |
| } |
| return false; |
| } |
| |
| // Attempt to unwrap the master key with the passkey key |
| if (!crypto_->DecryptVaultKeysetOld(cipher_text, keyset_key, vault_keyset)) { |
| if (error) { |
| *error = Mount::MOUNT_ERROR_KEY_FAILURE; |
| } |
| return false; |
| } |
| |
| return true; |
| } |
| |
| } // namespace cryptohome |
