| // Copyright 2012 Google Inc. |
| // |
| // 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. |
| |
| // Utility methods for handling the Ticl persistent state. |
| |
| #include "google/cacheinvalidation/impl/persistence-utils.h" |
| |
| namespace invalidation { |
| |
| void PersistenceUtils::SerializeState( |
| PersistentTiclState state, DigestFunction* digest_fn, string* result) { |
| string mac = GenerateMac(state, digest_fn); |
| PersistentStateBlob blob; |
| blob.mutable_ticl_state()->CopyFrom(state); |
| blob.set_authentication_code(mac); |
| blob.SerializeToString(result); |
| } |
| |
| bool PersistenceUtils::DeserializeState( |
| Logger* logger, const string& state_blob_bytes, DigestFunction* digest_fn, |
| PersistentTiclState* ticl_state) { |
| PersistentStateBlob state_blob; |
| state_blob.ParseFromString(state_blob_bytes); |
| if (!state_blob.IsInitialized()) { |
| TLOG(logger, WARNING, "could not parse state blob from %s", |
| state_blob_bytes.c_str()); |
| return false; |
| } |
| |
| // Check the mac in the envelope against the recomputed mac from the state. |
| ticl_state->CopyFrom(state_blob.ticl_state()); |
| const string& mac = GenerateMac(*ticl_state, digest_fn); |
| if (mac != state_blob.authentication_code()) { |
| TLOG(logger, WARNING, "Ticl state failed MAC check: computed %s vs %s", |
| mac.c_str(), state_blob.authentication_code().c_str()); |
| return false; |
| } |
| return true; |
| } |
| |
| string PersistenceUtils::GenerateMac( |
| const PersistentTiclState& state, DigestFunction* digest_fn) { |
| string serialized; |
| state.SerializeToString(&serialized); |
| digest_fn->Reset(); |
| digest_fn->Update(serialized); |
| return digest_fn->GetDigest(); |
| } |
| |
| } // namespace invalidation |