hardcoresushi/libcryfs
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CryFS uses the cipher specified in the configuration file

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This commit is contained in:
Sebastian Messmer 2015-07-29 12:08:39 +02:00
parent a31b5160c9
commit 84cd362d48
2 changed files with 32 additions and 22 deletions
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45
src/CryDevice.cpp
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@ -37,23 +37,7 @@ namespace cryfs {
constexpr uint32_t CryDevice::BLOCKSIZE_BYTES; constexpr uint32_t CryDevice::BLOCKSIZE_BYTES;
CryDevice::CryDevice(unique_ref<CryConfig> config, unique_ref<BlockStore> blockStore) CryDevice::CryDevice(unique_ref<CryConfig> config, unique_ref<BlockStore> blockStore)
: _blobStore(make_unique_ref<BlobStoreOnBlocks>(make_unique_ref<CachingBlockStore>(make_unique_ref<EncryptedBlockStore<Cipher>>(std::move(blockStore), GetEncryptionKey(config.get()))), BLOCKSIZE_BYTES)), _rootKey(GetOrCreateRootKey(config.get())) { : _blobStore(make_unique_ref<BlobStoreOnBlocks>(make_unique_ref<CachingBlockStore>(CreateEncryptedBlockStore(*config, std::move(blockStore))), BLOCKSIZE_BYTES)), _rootKey(GetOrCreateRootKey(config.get())) {
}
Key CryDevice::GetOrCreateRootKey(CryConfig *config) {
string root_key = config->RootBlob();
if (root_key == "") {
auto new_key = CreateRootBlobAndReturnKey();
config->SetRootBlob(new_key.ToString());
config->save();
return new_key;
}
return Key::FromString(root_key);
}
CryDevice::Cipher::EncryptionKey CryDevice::GetEncryptionKey(CryConfig *config) {
return Cipher::EncryptionKey::FromString(config->EncryptionKey());
} }
Key CryDevice::CreateRootBlobAndReturnKey() { Key CryDevice::CreateRootBlobAndReturnKey() {
@ -136,4 +120,31 @@ void CryDevice::RemoveBlob(const blockstore::Key &key) {
} }
} }
Key CryDevice::GetOrCreateRootKey(CryConfig *config) {
string root_key = config->RootBlob();
if (root_key == "") {
auto new_key = CreateRootBlobAndReturnKey();
config->SetRootBlob(new_key.ToString());
config->save();
return new_key;
}
return Key::FromString(root_key);
}
cpputils::unique_ref<blockstore::BlockStore> CryDevice::CreateEncryptedBlockStore(const CryConfig &config, unique_ref<BlockStore> baseBlockStore) {
//TODO Can we somehow ensure that the if/else chain here doesn't forget a valid value?
//TODO Test that CryFS is using the specified cipher
std::string cipherName = config.Cipher();
if (cipherName == "aes-256-gcm") {
using Cipher = blockstore::encrypted::AES256_GCM;
return make_unique_ref<EncryptedBlockStore<Cipher>>(std::move(baseBlockStore), Cipher::EncryptionKey::FromString(config.EncryptionKey()));
} else if (cipherName == "aes-256-cfb") {
using Cipher = blockstore::encrypted::AES256_CFB;
return make_unique_ref<EncryptedBlockStore<Cipher>>(std::move(baseBlockStore), Cipher::EncryptionKey::FromString(config.EncryptionKey()));
} else {
ASSERT(false, "Unknown cipher");
}
}
} }

9
src/CryDevice.h
View File

@ -18,8 +18,6 @@ class CryDevice: public fspp::Device {
public: public:
static constexpr uint32_t BLOCKSIZE_BYTES = 32 * 1024; static constexpr uint32_t BLOCKSIZE_BYTES = 32 * 1024;
using Cipher = CryConfigLoader::Cipher;
CryDevice(cpputils::unique_ref<CryConfig> config, cpputils::unique_ref<blockstore::BlockStore> blockStore); CryDevice(cpputils::unique_ref<CryConfig> config, cpputils::unique_ref<blockstore::BlockStore> blockStore);
virtual ~CryDevice(); virtual ~CryDevice();
@ -34,14 +32,15 @@ public:
boost::optional<cpputils::unique_ref<DirBlob>> LoadDirBlob(const boost::filesystem::path &path); boost::optional<cpputils::unique_ref<DirBlob>> LoadDirBlob(const boost::filesystem::path &path);
private: private:
blockstore::Key GetOrCreateRootKey(CryConfig *config);
Cipher::EncryptionKey GetEncryptionKey(CryConfig *config);
blockstore::Key CreateRootBlobAndReturnKey();
cpputils::unique_ref<blobstore::BlobStore> _blobStore; cpputils::unique_ref<blobstore::BlobStore> _blobStore;
blockstore::Key _rootKey; blockstore::Key _rootKey;
blockstore::Key GetOrCreateRootKey(CryConfig *config);
blockstore::Key CreateRootBlobAndReturnKey();
static cpputils::unique_ref<blockstore::BlockStore> CreateEncryptedBlockStore(const CryConfig &config, cpputils::unique_ref<blockstore::BlockStore> baseBlockStore);
DISALLOW_COPY_AND_ASSIGN(CryDevice); DISALLOW_COPY_AND_ASSIGN(CryDevice);
}; };