diff --git a/KeyStorage.cpp b/KeyStorage.cpp index 035c7b7..9dd4991 100644 --- a/KeyStorage.cpp +++ b/KeyStorage.cpp @@ -202,7 +202,7 @@ static KeymasterOperation begin(Keymaster& keymaster, const std::string& dir, km::KeyPurpose purpose, const km::AuthorizationSet& keyParams, const km::AuthorizationSet& opParams, const km::HardwareAuthToken& authToken, - km::AuthorizationSet* outParams) { + km::AuthorizationSet* outParams, bool keepOld) { auto kmKeyPath = dir + "/" + kFn_keymaster_key_blob; std::string kmKey; if (!readFileToString(kmKeyPath, &kmKey)) return KeymasterOperation(); @@ -219,12 +219,14 @@ static KeymasterOperation begin(Keymaster& keymaster, const std::string& dir, if (!keymaster.upgradeKey(kmKey, keyParams, &newKey)) return KeymasterOperation(); auto newKeyPath = dir + "/" + kFn_keymaster_key_blob_upgraded; if (!writeStringToFile(newKey, newKeyPath)) return KeymasterOperation(); - if (rename(newKeyPath.c_str(), kmKeyPath.c_str()) != 0) { - PLOG(ERROR) << "Unable to move upgraded key to location: " << kmKeyPath; - return KeymasterOperation(); - } - if (!keymaster.deleteKey(kmKey)) { - LOG(ERROR) << "Key deletion failed during upgrade, continuing anyway: " << dir; + if (!keepOld) { + if (rename(newKeyPath.c_str(), kmKeyPath.c_str()) != 0) { + PLOG(ERROR) << "Unable to move upgraded key to location: " << kmKeyPath; + return KeymasterOperation(); + } + if (!keymaster.deleteKey(kmKey)) { + LOG(ERROR) << "Key deletion failed during upgrade, continuing anyway: " << dir; + } } kmKey = newKey; LOG(INFO) << "Key upgraded: " << dir; @@ -233,12 +235,12 @@ static KeymasterOperation begin(Keymaster& keymaster, const std::string& dir, static bool encryptWithKeymasterKey(Keymaster& keymaster, const std::string& dir, const km::AuthorizationSet& keyParams, - const km::HardwareAuthToken& authToken, - const KeyBuffer& message, std::string* ciphertext) { + const km::HardwareAuthToken& authToken, const KeyBuffer& message, + std::string* ciphertext, bool keepOld) { km::AuthorizationSet opParams; km::AuthorizationSet outParams; - auto opHandle = - begin(keymaster, dir, km::KeyPurpose::ENCRYPT, keyParams, opParams, authToken, &outParams); + auto opHandle = begin(keymaster, dir, km::KeyPurpose::ENCRYPT, keyParams, opParams, authToken, + &outParams, keepOld); if (!opHandle) return false; auto nonceBlob = outParams.GetTagValue(km::TAG_NONCE); if (!nonceBlob.isOk()) { @@ -262,13 +264,14 @@ static bool encryptWithKeymasterKey(Keymaster& keymaster, const std::string& dir static bool decryptWithKeymasterKey(Keymaster& keymaster, const std::string& dir, const km::AuthorizationSet& keyParams, const km::HardwareAuthToken& authToken, - const std::string& ciphertext, KeyBuffer* message) { + const std::string& ciphertext, KeyBuffer* message, + bool keepOld) { auto nonce = ciphertext.substr(0, GCM_NONCE_BYTES); auto bodyAndMac = ciphertext.substr(GCM_NONCE_BYTES); auto opParams = km::AuthorizationSetBuilder().Authorization(km::TAG_NONCE, km::support::blob2hidlVec(nonce)); - auto opHandle = - begin(keymaster, dir, km::KeyPurpose::DECRYPT, keyParams, opParams, authToken, nullptr); + auto opHandle = begin(keymaster, dir, km::KeyPurpose::DECRYPT, keyParams, opParams, authToken, + nullptr, keepOld); if (!opHandle) return false; if (!opHandle.updateCompletely(bodyAndMac, message)) return false; if (!opHandle.finish(nullptr)) return false; @@ -474,7 +477,8 @@ bool storeKey(const std::string& dir, const KeyAuthentication& auth, const KeyBu km::AuthorizationSet keyParams; km::HardwareAuthToken authToken; std::tie(keyParams, authToken) = beginParams(auth, appId); - if (!encryptWithKeymasterKey(keymaster, dir, keyParams, authToken, key, &encryptedKey)) + if (!encryptWithKeymasterKey(keymaster, dir, keyParams, authToken, key, &encryptedKey, + false)) return false; } else { if (!encryptWithoutKeymaster(appId, key, &encryptedKey)) return false; @@ -502,7 +506,8 @@ bool storeKeyAtomically(const std::string& key_path, const std::string& tmp_path return true; } -bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffer* key) { +bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffer* key, + bool keepOld) { std::string version; if (!readFileToString(dir + "/" + kFn_version, &version)) return false; if (version != kCurrentVersion) { @@ -527,7 +532,8 @@ bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffe km::AuthorizationSet keyParams; km::HardwareAuthToken authToken; std::tie(keyParams, authToken) = beginParams(auth, appId); - if (!decryptWithKeymasterKey(keymaster, dir, keyParams, authToken, encryptedMessage, key)) + if (!decryptWithKeymasterKey(keymaster, dir, keyParams, authToken, encryptedMessage, key, + keepOld)) return false; } else { if (!decryptWithoutKeymaster(appId, encryptedMessage, key)) return false; diff --git a/KeyStorage.h b/KeyStorage.h index 786e5b4..6aaf3ad 100644 --- a/KeyStorage.h +++ b/KeyStorage.h @@ -61,7 +61,8 @@ bool storeKeyAtomically(const std::string& key_path, const std::string& tmp_path const KeyAuthentication& auth, const KeyBuffer& key); // Retrieve the key from the named directory. -bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffer* key); +bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffer* key, + bool keepOld = false); // Securely destroy the key stored in the named directory and delete the directory. bool destroyKey(const std::string& dir); diff --git a/KeyUtil.cpp b/KeyUtil.cpp index a17b8b2..12cae9b 100644 --- a/KeyUtil.cpp +++ b/KeyUtil.cpp @@ -169,10 +169,10 @@ bool retrieveAndInstallKey(bool create_if_absent, const KeyAuthentication& key_a } bool retrieveKey(bool create_if_absent, const std::string& key_path, const std::string& tmp_path, - KeyBuffer* key) { + KeyBuffer* key, bool keepOld) { if (pathExists(key_path)) { LOG(DEBUG) << "Key exists, using: " << key_path; - if (!retrieveKey(key_path, kEmptyAuthentication, key)) return false; + if (!retrieveKey(key_path, kEmptyAuthentication, key, keepOld)) return false; } else { if (!create_if_absent) { LOG(ERROR) << "No key found in " << key_path; diff --git a/KeyUtil.h b/KeyUtil.h index b4115f4..7ee6725 100644 --- a/KeyUtil.h +++ b/KeyUtil.h @@ -33,7 +33,7 @@ bool retrieveAndInstallKey(bool create_if_absent, const KeyAuthentication& key_a const std::string& key_path, const std::string& tmp_path, std::string* key_ref); bool retrieveKey(bool create_if_absent, const std::string& key_path, const std::string& tmp_path, - KeyBuffer* key); + KeyBuffer* key, bool keepOld = true); } // namespace vold } // namespace android diff --git a/MetadataCrypt.cpp b/MetadataCrypt.cpp index e156424..8b4d04e 100644 --- a/MetadataCrypt.cpp +++ b/MetadataCrypt.cpp @@ -30,6 +30,7 @@ #include +#include #include #include #include @@ -40,6 +41,7 @@ #include "EncryptInplace.h" #include "KeyStorage.h" #include "KeyUtil.h" +#include "Keymaster.h" #include "Utils.h" #include "VoldUtil.h" #include "secontext.h" @@ -52,6 +54,9 @@ using android::vold::KeyBuffer; 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"; + static bool mount_via_fs_mgr(const char* mount_point, const char* blk_device) { // fs_mgr_do_mount runs fsck. Use setexeccon to run trusted // partitions in the fsck domain. @@ -74,12 +79,41 @@ static bool mount_via_fs_mgr(const char* mount_point, const char* blk_device) { return true; } +namespace android { +namespace vold { + +// 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(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 read_key(struct fstab_rec const* data_rec, bool create_if_absent, KeyBuffer* key) { if (!data_rec->key_dir) { LOG(ERROR) << "Failed to get key_dir"; return false; } std::string key_dir = data_rec->key_dir; + std::string sKey; auto dir = key_dir + "/key"; LOG(DEBUG) << "key_dir/key: " << dir; if (fs_mkdirs(dir.c_str(), 0700)) { @@ -87,10 +121,30 @@ static bool read_key(struct fstab_rec const* data_rec, bool create_if_absent, Ke return false; } auto temp = key_dir + "/tmp"; - if (!android::vold::retrieveKey(create_if_absent, dir, temp, key)) return false; + 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 (!android::vold::retrieveKey(create_if_absent, dir, temp, key, needs_cp)) return false; + if (needs_cp && pathExists(newKeyPath)) std::thread(commit_key, dir).detach(); return true; } +} // namespace vold +} // namespace android + static KeyBuffer default_key_params(const std::string& real_blkdev, const KeyBuffer& key) { KeyBuffer hex_key; if (android::vold::StrToHex(key, hex_key) != android::OK) {