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/*
* Copyright (C) 2017 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 "grant_store.h"
#include "blob.h"
#include <algorithm>
#include <sstream>
namespace keystore {
static constexpr uint64_t kInvalidGrantNo = std::numeric_limits<uint64_t>::max();
static const char* kKeystoreGrantInfix = "_KEYSTOREGRANT_";
static constexpr size_t kKeystoreGrantInfixLength = 15;
Grant::Grant(const KeyBlobEntry& entry, const uint64_t grant_no)
: entry_(entry), grant_no_(grant_no) {}
static std::pair<uint64_t, std::string> parseGrantAlias(const std::string& grantAlias) {
auto pos = grantAlias.rfind(kKeystoreGrantInfix);
if (pos == std::string::npos) return {kInvalidGrantNo, ""};
std::stringstream s(grantAlias.substr(pos + kKeystoreGrantInfixLength));
std::string wrapped_alias = grantAlias.substr(0, pos);
uint64_t grant_no = kInvalidGrantNo;
s >> grant_no;
if (s.fail() || grant_no == kInvalidGrantNo) return {kInvalidGrantNo, ""};
return {grant_no, wrapped_alias};
}
std::string GrantStore::put(const uid_t uid, const LockedKeyBlobEntry& lockedEntry) {
std::unique_lock<std::shared_mutex> lock(mutex_);
std::stringstream s;
KeyBlobEntry blobEntry = *lockedEntry;
s << blobEntry.alias() << kKeystoreGrantInfix;
std::set<Grant, std::less<>>& uid_grant_list = grants_[uid];
bool success = false;
auto iterator =
std::find_if(uid_grant_list.begin(), uid_grant_list.end(),
[&](const Grant& entry) { return success = entry.entry_ == blobEntry; });
while (!success) {
std::tie(iterator, success) = uid_grant_list.emplace(blobEntry, std::rand());
}
s << iterator->grant_no_;
return s.str();
}
ReadLockedGrant GrantStore::get(const uid_t uid, const std::string& alias) const {
std::shared_lock<std::shared_mutex> lock(mutex_);
uint64_t grant_no;
std::string wrappedAlias;
std::tie(grant_no, wrappedAlias) = parseGrantAlias(alias);
if (grant_no == kInvalidGrantNo) return {};
auto uid_set_iter = grants_.find(uid);
if (uid_set_iter == grants_.end()) return {};
auto& uid_grant_list = uid_set_iter->second;
auto grant = uid_grant_list.find(grant_no);
if (grant == uid_grant_list.end()) return {};
if (grant->entry_.alias() != wrappedAlias) return {};
return {&(*grant), std::move(lock)};
}
bool GrantStore::removeByFileAlias(const uid_t granteeUid, const LockedKeyBlobEntry& lockedEntry) {
std::unique_lock<std::shared_mutex> lock(mutex_);
auto& uid_grant_list = grants_[granteeUid];
for (auto i = uid_grant_list.begin(); i != uid_grant_list.end(); ++i) {
if (i->entry_ == *lockedEntry) {
uid_grant_list.erase(i);
return true;
}
}
return false;
}
void GrantStore::removeAllGrantsToKey(const uid_t granterUid, const std::string& alias) {
std::unique_lock<std::shared_mutex> lock(mutex_);
for (auto& uid_grant_list : grants_) {
for (auto i = uid_grant_list.second.begin(); i != uid_grant_list.second.end(); ++i) {
if (i->entry_.alias() == alias && i->entry_.uid() == granterUid) {
uid_grant_list.second.erase(i);
break;
}
}
}
}
void GrantStore::removeAllGrantsToUid(const uid_t granteeUid) {
std::unique_lock<std::shared_mutex> lock(mutex_);
grants_.erase(granteeUid);
}
} // namespace keystore
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