| /* |
| * Copyright (C) 2016 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 "MetadataCrypt.h" |
| #include "KeyBuffer.h" |
| |
| #include <algorithm> |
| #include <string> |
| #include <thread> |
| #include <vector> |
| |
| #include <fcntl.h> |
| #include <sys/param.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/properties.h> |
| #include <android-base/unique_fd.h> |
| #include <cutils/fs.h> |
| #include <fs_mgr.h> |
| #include <libdm/dm.h> |
| |
| #include "Checkpoint.h" |
| #include "CryptoType.h" |
| #include "EncryptInplace.h" |
| #include "KeyStorage.h" |
| #include "KeyUtil.h" |
| #include "Keymaster.h" |
| #include "Utils.h" |
| #include "VoldUtil.h" |
| |
| #define TABLE_LOAD_RETRIES 10 |
| |
| namespace android { |
| namespace vold { |
| |
| using android::fs_mgr::FstabEntry; |
| using android::fs_mgr::GetEntryForMountPoint; |
| using android::vold::KeyBuffer; |
| using namespace android::dm; |
| |
| static const std::string kDmNameUserdata = "userdata"; |
| |
| static const char* kFn_keymaster_key_blob = "keymaster_key_blob"; |
| static const char* kFn_keymaster_key_blob_upgraded = "keymaster_key_blob_upgraded"; |
| |
| constexpr CryptoType supported_crypto_types[] = {aes_256_xts, adiantum}; |
| |
| static_assert(validateSupportedCryptoTypes(64, supported_crypto_types, |
| array_length(supported_crypto_types)), |
| "We have a CryptoType which was incompletely constructed."); |
| |
| constexpr CryptoType legacy_aes_256_xts = |
| CryptoType().set_config_name("aes-256-xts").set_kernel_name("AES-256-XTS").set_keysize(64); |
| |
| constexpr CryptoType legacy_crypto_types[] = {legacy_aes_256_xts}; |
| |
| static_assert(validateSupportedCryptoTypes(64, legacy_crypto_types, |
| array_length(legacy_crypto_types)), |
| "We have a CryptoType which was incompletely constructed."); |
| |
| static bool mount_via_fs_mgr(const char* mount_point, const char* blk_device) { |
| // We're about to mount data not verified by verified boot. Tell Keymaster that early boot has |
| // ended. |
| // |
| // TODO(paulcrowley): Make a Keymaster singleton or something, so we don't have to repeatedly |
| // open and initialize the service. |
| ::android::vold::Keymaster keymaster; |
| keymaster.earlyBootEnded(); |
| |
| // fs_mgr_do_mount runs fsck. Use setexeccon to run trusted |
| // partitions in the fsck domain. |
| if (setexeccon(android::vold::sFsckContext)) { |
| PLOG(ERROR) << "Failed to setexeccon"; |
| return false; |
| } |
| auto mount_rc = fs_mgr_do_mount(&fstab_default, const_cast<char*>(mount_point), |
| const_cast<char*>(blk_device), nullptr, |
| android::vold::cp_needsCheckpoint()); |
| if (setexeccon(nullptr)) { |
| PLOG(ERROR) << "Failed to clear setexeccon"; |
| return false; |
| } |
| if (mount_rc != 0) { |
| LOG(ERROR) << "fs_mgr_do_mount failed with rc " << mount_rc; |
| return false; |
| } |
| LOG(DEBUG) << "Mounted " << mount_point; |
| return true; |
| } |
| |
| // Note: It is possible to orphan a key if it is removed before deleting |
| // Update this once keymaster APIs change, and we have a proper commit. |
| static void commit_key(const std::string& dir) { |
| while (!android::base::WaitForProperty("vold.checkpoint_committed", "1")) { |
| LOG(ERROR) << "Wait for boot timed out"; |
| } |
| Keymaster keymaster; |
| auto keyPath = dir + "/" + kFn_keymaster_key_blob; |
| auto newKeyPath = dir + "/" + kFn_keymaster_key_blob_upgraded; |
| std::string key; |
| |
| if (!android::base::ReadFileToString(keyPath, &key)) { |
| LOG(ERROR) << "Failed to read old key: " << dir; |
| return; |
| } |
| if (rename(newKeyPath.c_str(), keyPath.c_str()) != 0) { |
| PLOG(ERROR) << "Unable to move upgraded key to location: " << keyPath; |
| return; |
| } |
| if (!keymaster.deleteKey(key)) { |
| LOG(ERROR) << "Key deletion failed during upgrade, continuing anyway: " << dir; |
| } |
| LOG(INFO) << "Old Key deleted: " << dir; |
| } |
| |
| static bool retrieveMetadataKey(bool create_if_absent, const std::string& key_path, |
| const std::string& tmp_path, KeyBuffer* key, bool keepOld) { |
| if (pathExists(key_path)) { |
| LOG(DEBUG) << "Key exists, using: " << key_path; |
| if (!retrieveKey(key_path, kEmptyAuthentication, key, keepOld)) return false; |
| } else { |
| if (!create_if_absent) { |
| LOG(ERROR) << "No key found in " << key_path; |
| return false; |
| } |
| LOG(INFO) << "Creating new key in " << key_path; |
| if (!randomKey(key)) return false; |
| if (!storeKeyAtomically(key_path, tmp_path, kEmptyAuthentication, *key)) return false; |
| } |
| return true; |
| } |
| |
| static bool read_key(const FstabEntry& data_rec, bool create_if_absent, KeyBuffer* key) { |
| if (data_rec.metadata_key_dir.empty()) { |
| LOG(ERROR) << "Failed to get metadata_key_dir"; |
| return false; |
| } |
| std::string metadata_key_dir = data_rec.metadata_key_dir; |
| std::string sKey; |
| auto dir = metadata_key_dir + "/key"; |
| LOG(DEBUG) << "metadata_key_dir/key: " << dir; |
| if (fs_mkdirs(dir.c_str(), 0700)) { |
| PLOG(ERROR) << "Creating directories: " << dir; |
| return false; |
| } |
| auto temp = metadata_key_dir + "/tmp"; |
| auto newKeyPath = dir + "/" + kFn_keymaster_key_blob_upgraded; |
| /* If we have a leftover upgraded key, delete it. |
| * We either failed an update and must return to the old key, |
| * or we rebooted before commiting the keys in a freak accident. |
| * Either way, we can re-upgrade the key if we need to. |
| */ |
| Keymaster keymaster; |
| if (pathExists(newKeyPath)) { |
| if (!android::base::ReadFileToString(newKeyPath, &sKey)) |
| LOG(ERROR) << "Failed to read old key: " << dir; |
| else if (!keymaster.deleteKey(sKey)) |
| LOG(ERROR) << "Old key deletion failed, continuing anyway: " << dir; |
| else |
| unlink(newKeyPath.c_str()); |
| } |
| bool needs_cp = cp_needsCheckpoint(); |
| if (!retrieveMetadataKey(create_if_absent, dir, temp, key, needs_cp)) return false; |
| if (needs_cp && pathExists(newKeyPath)) std::thread(commit_key, dir).detach(); |
| return true; |
| } |
| |
| static bool get_number_of_sectors(const std::string& real_blkdev, uint64_t* nr_sec) { |
| if (android::vold::GetBlockDev512Sectors(real_blkdev, nr_sec) != android::OK) { |
| PLOG(ERROR) << "Unable to measure size of " << real_blkdev; |
| return false; |
| } |
| return true; |
| } |
| |
| static const CryptoType& lookup_cipher_in_table(const CryptoType table[], int table_len, |
| const std::string& cipher_name) { |
| if (cipher_name.empty()) return table[0]; |
| for (int i = 0; i < table_len; i++) { |
| if (cipher_name == table[i].get_config_name()) { |
| return table[i]; |
| } |
| } |
| return invalid_crypto_type; |
| } |
| |
| static const CryptoType& lookup_cipher(const std::string& cipher_name, bool is_legacy) { |
| if (is_legacy) { |
| return lookup_cipher_in_table(legacy_crypto_types, array_length(legacy_crypto_types), |
| cipher_name); |
| } else { |
| return lookup_cipher_in_table(supported_crypto_types, array_length(supported_crypto_types), |
| cipher_name); |
| } |
| } |
| |
| static bool create_crypto_blk_dev(const std::string& dm_name, const FstabEntry* data_rec, |
| const KeyBuffer& key, std::string* crypto_blkdev) { |
| uint64_t nr_sec; |
| if (!get_number_of_sectors(data_rec->blk_device, &nr_sec)) return false; |
| |
| bool is_legacy; |
| if (!DmTargetDefaultKey::IsLegacy(&is_legacy)) return false; |
| |
| auto cipher = lookup_cipher(data_rec->metadata_cipher, is_legacy); |
| if (cipher.get_kernel_name() == nullptr) { |
| LOG(ERROR) << "No metadata cipher named " << data_rec->metadata_cipher |
| << " found, is_legacy=" << is_legacy; |
| return false; |
| } |
| |
| KeyBuffer hex_key_buffer; |
| if (android::vold::StrToHex(key, hex_key_buffer) != android::OK) { |
| LOG(ERROR) << "Failed to turn key to hex"; |
| return false; |
| } |
| std::string hex_key(hex_key_buffer.data(), hex_key_buffer.size()); |
| |
| // Non-legacy driver always sets DUN |
| bool set_dun = !is_legacy || android::base::GetBoolProperty("ro.crypto.set_dun", false); |
| if (!set_dun && data_rec->fs_mgr_flags.checkpoint_blk) { |
| LOG(ERROR) << "Block checkpoints and metadata encryption require ro.crypto.set_dun option"; |
| return false; |
| } |
| |
| DmTable table; |
| table.Emplace<DmTargetDefaultKey>(0, nr_sec, cipher.get_kernel_name(), hex_key, |
| data_rec->blk_device, 0, is_legacy, set_dun); |
| |
| auto& dm = DeviceMapper::Instance(); |
| for (int i = 0;; i++) { |
| if (dm.CreateDevice(dm_name, table)) { |
| break; |
| } |
| if (i + 1 >= TABLE_LOAD_RETRIES) { |
| PLOG(ERROR) << "Could not create default-key device " << dm_name; |
| return false; |
| } |
| PLOG(INFO) << "Could not create default-key device, retrying"; |
| usleep(500000); |
| } |
| |
| if (!dm.GetDmDevicePathByName(dm_name, crypto_blkdev)) { |
| LOG(ERROR) << "Cannot retrieve default-key device status " << dm_name; |
| return false; |
| } |
| return true; |
| } |
| |
| bool fscrypt_mount_metadata_encrypted(const std::string& blk_device, const std::string& mount_point, |
| bool needs_encrypt) { |
| LOG(DEBUG) << "fscrypt_mount_metadata_encrypted: " << mount_point << " " << needs_encrypt; |
| auto encrypted_state = android::base::GetProperty("ro.crypto.state", ""); |
| if (encrypted_state != "" && encrypted_state != "encrypted") { |
| LOG(DEBUG) << "fscrypt_enable_crypto got unexpected starting state: " << encrypted_state; |
| return false; |
| } |
| |
| auto data_rec = GetEntryForMountPoint(&fstab_default, mount_point); |
| if (!data_rec) { |
| LOG(ERROR) << "Failed to get data_rec for " << mount_point; |
| return false; |
| } |
| if (blk_device != data_rec->blk_device) { |
| LOG(ERROR) << "blk_device " << blk_device << " does not match fstab entry " |
| << data_rec->blk_device << " for " << mount_point; |
| return false; |
| } |
| KeyBuffer key; |
| if (!read_key(*data_rec, needs_encrypt, &key)) return false; |
| |
| std::string crypto_blkdev; |
| if (!create_crypto_blk_dev(kDmNameUserdata, data_rec, key, &crypto_blkdev)) return false; |
| |
| // FIXME handle the corrupt case |
| if (needs_encrypt) { |
| uint64_t nr_sec; |
| if (!get_number_of_sectors(data_rec->blk_device, &nr_sec)) return false; |
| LOG(INFO) << "Beginning inplace encryption, nr_sec: " << nr_sec; |
| off64_t size_already_done = 0; |
| auto rc = cryptfs_enable_inplace(crypto_blkdev.data(), blk_device.data(), nr_sec, |
| &size_already_done, nr_sec, 0, false); |
| if (rc != 0) { |
| LOG(ERROR) << "Inplace crypto failed with code: " << rc; |
| return false; |
| } |
| if (static_cast<uint64_t>(size_already_done) != nr_sec) { |
| LOG(ERROR) << "Inplace crypto only got up to sector: " << size_already_done; |
| return false; |
| } |
| LOG(INFO) << "Inplace encryption complete"; |
| } |
| |
| LOG(DEBUG) << "Mounting metadata-encrypted filesystem:" << mount_point; |
| mount_via_fs_mgr(data_rec->mount_point.c_str(), crypto_blkdev.c_str()); |
| return true; |
| } |
| |
| } // namespace vold |
| } // namespace android |
