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/**
* Copyright (C) 2021-2024 Saturneric <eric@bktus.com>
*
* This file is part of GpgFrontend.
*
* GpgFrontend is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GpgFrontend is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GpgFrontend. If not, see <https://www.gnu.org/licenses/>.
*
* The initial version of the source code is inherited from
* the gpg4usb project, which is under GPL-3.0-or-later.
*
* All the source code of GpgFrontend was modified and released by
* Saturneric <eric@bktus.com> starting on May 12, 2021.
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#include "EMailCredentialStore.h"
#include "GFModule.h"
#include "GFSDKBasic.h"
namespace {
/// Credentials are keyed by account id, not by host or username: re-hosting an
/// account or correcting its username must not orphan the stored secret.
auto CredentialKey(const QString& account_id) -> QString {
return QString("mail/cred/%1").arg(account_id);
}
} // namespace
namespace EMailCredentialStore {
auto CurrentProtection() -> ProtectionLevel {
switch (GFAppKeyProtectionLevel()) {
case 0:
return ProtectionLevel::kNONE;
case 1:
return ProtectionLevel::kKEYCHAIN;
case 2:
return ProtectionLevel::kPIN;
default:
return ProtectionLevel::kUNKNOWN;
}
}
auto MayPersistSilently() -> bool {
const auto protection = CurrentProtection();
// kUNKNOWN is treated as kNONE rather than given the benefit of the doubt:
// if we cannot establish that the key is protected, we have to assume it is
// not. Guessing the other way stores a password on a promise nobody made.
return protection == ProtectionLevel::kKEYCHAIN ||
protection == ProtectionLevel::kPIN;
}
auto Save(const QString& account_id, const EMailSecret& password) -> bool {
if (account_id.isEmpty()) return false;
// Storing is not optional: there is no password prompt anywhere, so an
// account without a stored password simply cannot be used. Refusing here
// would not protect anyone, it would just break the feature.
//
// The protection level still matters though, so it is recorded rather than
// shown. Everything here is encrypted under the application secure key, and
// when that key is itself unprotected this is protection in name only --
// worth having in a log when someone is working out how exposed a profile
// is, even though it is not worth interrupting them over.
if (!MayPersistSilently()) {
LOG_WARN(
"storing a mail credential while the application key is unprotected; "
"it is only as protected as the profile itself");
}
//
// Both arguments are handed over owned, from the allocators the SDK will
// release them through: the key ordinary, the secret secure. Passing a
// QByteArray's internal pointer here would have the SDK free memory Qt owns.
auto* secret = password.ToSecureCString();
if (secret == nullptr) {
LOG_ERROR("could not allocate a secure buffer for a mail credential");
return false;
}
const auto result =
GFSecDurableCacheSave((CredentialKey(account_id)).toUtf8().constData(), secret);
if (result != 0) LOG_ERROR("failed to store mail credential");
return result == 0;
}
auto Load(const QString& account_id) -> EMailSecretPtr {
if (account_id.isEmpty()) return std::make_shared<EMailSecret>();
auto* raw = GFSecDurableCacheGet((CredentialKey(account_id)).toUtf8().constData());
if (raw == nullptr) return std::make_shared<EMailSecret>();
// AdoptCString copies the bytes out, wipes the SDK's buffer and frees it to
// the secure allocator it came from, so the secret exists in exactly one
// place from here on -- and that place can actually be erased, which a
// QString could not be. See EMailSecret.
return EMailSecret::AdoptCString(raw);
}
auto Has(const QString& account_id) -> bool {
return !Load(account_id)->IsEmpty();
}
void Remove(const QString& account_id) {
if (account_id.isEmpty()) return;
GFSecDurableCacheRemove((CredentialKey(account_id)).toUtf8().constData());
}
} // namespace EMailCredentialStore
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