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// Copyright 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/sync/engine_impl/apply_control_data_updates.h"
#include <stdint.h>
#include <vector>
#include "base/metrics/histogram_macros.h"
#include "components/sync/base/cryptographer.h"
#include "components/sync/engine_impl/conflict_resolver.h"
#include "components/sync/engine_impl/conflict_util.h"
#include "components/sync/engine_impl/syncer_util.h"
#include "components/sync/syncable/directory.h"
#include "components/sync/syncable/mutable_entry.h"
#include "components/sync/syncable/nigori_handler.h"
#include "components/sync/syncable/nigori_util.h"
#include "components/sync/syncable/syncable_write_transaction.h"
namespace syncer {
void ApplyControlDataUpdates(syncable::Directory* dir) {
syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir);
std::vector<int64_t> handles;
dir->GetUnappliedUpdateMetaHandles(&trans, ToFullModelTypeSet(ControlTypes()),
&handles);
// First, go through and manually apply any new top level datatype nodes (so
// that we don't have to worry about hitting a CONFLICT_HIERARCHY with an
// entry because we haven't applied its parent yet).
// TODO(sync): if at some point we support control datatypes with actual
// hierarchies we'll need to revisit this logic.
ModelTypeSet control_types = ControlTypes();
for (ModelTypeSet::Iterator iter = control_types.First(); iter.Good();
iter.Inc()) {
ModelType type = iter.Get();
syncable::MutableEntry entry(&trans, syncable::GET_TYPE_ROOT, type);
if (!entry.good())
continue;
if (!entry.GetIsUnappliedUpdate()) {
// If this is a type with client generated root, the root node has been
// created locally and might never be updated by the server. In that case
// it has to be marked as having the initial download completed (which is
// done by changing the root's base version to a value other than
// CHANGES_VERSION). This does nothing if the root's base version is
// already other than CHANGES_VERSION.
if (IsTypeWithClientGeneratedRoot(type)) {
dir->MarkInitialSyncEndedForType(&trans, type);
}
continue;
}
DCHECK_EQ(type, entry.GetServerModelType());
if (type == NIGORI) {
// Nigori node applications never fail.
ApplyNigoriUpdate(&trans, &entry, dir->GetCryptographer(&trans));
} else {
ApplyControlUpdate(&trans, &entry, dir->GetCryptographer(&trans));
}
}
// Go through the rest of the unapplied control updates, skipping over any
// top level folders.
for (std::vector<int64_t>::const_iterator iter = handles.begin();
iter != handles.end(); ++iter) {
syncable::MutableEntry entry(&trans, syncable::GET_BY_HANDLE, *iter);
CHECK(entry.good());
ModelType type = entry.GetServerModelType();
CHECK(ControlTypes().Has(type));
if (!entry.GetUniqueServerTag().empty()) {
// We should have already applied all top level control nodes.
DCHECK(!entry.GetIsUnappliedUpdate());
continue;
}
ApplyControlUpdate(&trans, &entry, dir->GetCryptographer(&trans));
}
}
// Update the nigori handler with the server's nigori node.
//
// If we have a locally modified nigori node, we merge them manually. This
// handles the case where two clients both set a different passphrase. The
// second client to attempt to commit will go into a state of having pending
// keys, unioned the set of encrypted types, and eventually re-encrypt
// everything with the passphrase of the first client and commit the set of
// merged encryption keys. Until the second client provides the pending
// passphrase, the cryptographer will preserve the encryption keys based on the
// local passphrase, while the nigori node will preserve the server encryption
// keys.
void ApplyNigoriUpdate(syncable::WriteTransaction* const trans,
syncable::MutableEntry* const entry,
Cryptographer* cryptographer) {
DCHECK(entry->GetIsUnappliedUpdate());
// We apply the nigori update regardless of whether there's a conflict or
// not in order to preserve any new encrypted types or encryption keys.
// TODO(zea): consider having this return a bool reflecting whether it was a
// valid update or not, and in the case of invalid updates not overwrite the
// local data.
const sync_pb::NigoriSpecifics& nigori = entry->GetServerSpecifics().nigori();
trans->directory()->GetNigoriHandler()->ApplyNigoriUpdate(nigori, trans);
// Make sure any unsynced changes are properly encrypted as necessary.
// We only perform this if the cryptographer is ready. If not, these are
// re-encrypted at SetDecryptionPassphrase time (via ReEncryptEverything).
// This logic covers the case where the nigori update marked new datatypes
// for encryption, but didn't change the passphrase.
if (cryptographer->is_ready()) {
// Note that we don't bother to encrypt any data for which IS_UNSYNCED
// == false here. The machine that turned on encryption should know about
// and re-encrypt all synced data. It's possible it could get interrupted
// during this process, but we currently reencrypt everything at startup
// as well, so as soon as a client is restarted with this datatype marked
// for encryption, all the data should be updated as necessary.
// If this fails, something is wrong with the cryptographer, but there's
// nothing we can do about it here.
DVLOG(1) << "Received new nigori, encrypting unsynced changes.";
syncable::ProcessUnsyncedChangesForEncryption(trans);
}
if (!entry->GetIsUnsynced()) { // Update only.
UpdateLocalDataFromServerData(trans, entry);
} else { // Conflict.
const sync_pb::EntitySpecifics& server_specifics =
entry->GetServerSpecifics();
const sync_pb::NigoriSpecifics& server_nigori = server_specifics.nigori();
const sync_pb::EntitySpecifics& local_specifics = entry->GetSpecifics();
const sync_pb::NigoriSpecifics& local_nigori = local_specifics.nigori();
// We initialize the new nigori with the server state, and will override
// it as necessary below.
sync_pb::EntitySpecifics new_specifics = entry->GetServerSpecifics();
sync_pb::NigoriSpecifics* new_nigori = new_specifics.mutable_nigori();
// If the cryptographer is not ready, another client set a new encryption
// passphrase. If we had migrated locally, we will re-migrate when the
// pending keys are provided. If we had set a new custom passphrase locally
// the user will have another chance to set a custom passphrase later
// (assuming they hadn't set a custom passphrase on the other client).
// Therefore, we only attempt to merge the nigori nodes if the cryptographer
// is ready.
// Note: we only update the encryption keybag if we're sure that we aren't
// invalidating the keystore_decryptor_token (i.e. we're either
// not migrated or we copying over all local state).
if (cryptographer->is_ready()) {
if (local_nigori.has_passphrase_type() &&
server_nigori.has_passphrase_type()) {
// They're both migrated, preserve the local nigori if the passphrase
// type is more conservative.
if (server_nigori.passphrase_type() ==
sync_pb::NigoriSpecifics::KEYSTORE_PASSPHRASE &&
local_nigori.passphrase_type() !=
sync_pb::NigoriSpecifics::KEYSTORE_PASSPHRASE) {
DCHECK(local_nigori.passphrase_type() ==
sync_pb::NigoriSpecifics::FROZEN_IMPLICIT_PASSPHRASE ||
local_nigori.passphrase_type() ==
sync_pb::NigoriSpecifics::CUSTOM_PASSPHRASE);
new_nigori->CopyFrom(local_nigori);
cryptographer->GetKeys(new_nigori->mutable_encryption_keybag());
}
} else if (!local_nigori.has_passphrase_type() &&
!server_nigori.has_passphrase_type()) {
// Set the explicit passphrase based on the local state. If the server
// had set an explict passphrase, we should have pending keys, so
// should not reach this code.
// Because neither side is migrated, we don't have to worry about the
// keystore decryptor token.
new_nigori->set_keybag_is_frozen(local_nigori.keybag_is_frozen());
cryptographer->GetKeys(new_nigori->mutable_encryption_keybag());
} else if (local_nigori.has_passphrase_type()) {
// Local is migrated but server is not. Copy over the local migrated
// data.
new_nigori->CopyFrom(local_nigori);
cryptographer->GetKeys(new_nigori->mutable_encryption_keybag());
} // else leave the new nigori with the server state.
}
// Always update to the safest set of encrypted types.
trans->directory()->GetNigoriHandler()->UpdateNigoriFromEncryptedTypes(
new_nigori, trans);
entry->PutSpecifics(new_specifics);
DVLOG(1) << "Resolving simple conflict, merging nigori nodes: " << entry;
conflict_util::OverwriteServerChanges(entry);
UMA_HISTOGRAM_ENUMERATION("Sync.ResolveSimpleConflict",
ConflictResolver::NIGORI_MERGE,
ConflictResolver::CONFLICT_RESOLUTION_SIZE);
}
}
void ApplyControlUpdate(syncable::WriteTransaction* const trans,
syncable::MutableEntry* const entry,
Cryptographer* cryptographer) {
DCHECK_NE(entry->GetServerModelType(), NIGORI);
DCHECK(entry->GetIsUnappliedUpdate());
if (entry->GetIsUnsynced()) {
// We just let the server win all conflicts with control types.
DVLOG(1) << "Ignoring local changes for control update.";
conflict_util::IgnoreLocalChanges(entry);
UMA_HISTOGRAM_ENUMERATION("Sync.ResolveSimpleConflict",
ConflictResolver::OVERWRITE_LOCAL,
ConflictResolver::CONFLICT_RESOLUTION_SIZE);
}
UpdateAttemptResponse response =
AttemptToUpdateEntry(trans, entry, cryptographer);
DCHECK_EQ(SUCCESS, response);
}
} // namespace syncer
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