File indexing completed on 2024-05-26 05:24:35

 /*
     utils/keyhelpers.cpp
 
     This file is part of libkleopatra, the KDE keymanagement library
     SPDX-FileCopyrightText: 2022 g10 Code GmbH
     SPDX-FileContributor: Ingo Klöcker <dev@ingo-kloecker.de>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include <config-libkleo.h>
 
 #include "keyhelpers.h"
 
 #include <libkleo/algorithm.h>
 #include <libkleo/compat.h>
 #include <libkleo/keycache.h>
 
 #include <libkleo_debug.h>
 
 #include <QDate>
 
 // needed for GPGME_VERSION_NUMBER
 #include <gpgme.h>
 
 #include <iterator>
 
 using namespace Kleo;
 using namespace GpgME;
 
 namespace
 {
 bool havePublicKeyForSignature(const GpgME::UserID::Signature &signature)
 {
     // GnuPG returns status "NoPublicKey" for missing signing keys, but also
     // for expired or revoked signing keys.
     return (signature.status() != GpgME::UserID::Signature::NoPublicKey) //
         || !KeyCache::instance()->findByKeyIDOrFingerprint(signature.signerKeyID()).isNull();
 }
 
 auto _getMissingSignerKeyIds(const std::vector<GpgME::UserID::Signature> &signatures)
 {
     return std::accumulate(std::begin(signatures), std::end(signatures), std::set<QString>{}, [](auto &keyIds, const auto &signature) {
         if (!havePublicKeyForSignature(signature)) {
             keyIds.insert(QLatin1StringView{signature.signerKeyID()});
         }
         return keyIds;
     });
 }
 }
 
 std::set<QString> Kleo::getMissingSignerKeyIds(const std::vector<GpgME::UserID> &userIds)
 {
     return std::accumulate(std::begin(userIds), std::end(userIds), std::set<QString>{}, [](auto &keyIds, const auto &userID) {
         if (!userID.isBad()) {
             const auto newKeyIds = _getMissingSignerKeyIds(userID.signatures());
             std::copy(std::begin(newKeyIds), std::end(newKeyIds), std::inserter(keyIds, std::end(keyIds)));
         }
         return keyIds;
     });
 }
 
 std::set<QString> Kleo::getMissingSignerKeyIds(const std::vector<GpgME::Key> &keys)
 {
     return std::accumulate(std::begin(keys), std::end(keys), std::set<QString>{}, [](auto &keyIds, const auto &key) {
         if (!key.isBad()) {
             const auto newKeyIds = getMissingSignerKeyIds(key.userIDs());
             std::copy(std::begin(newKeyIds), std::end(newKeyIds), std::inserter(keyIds, std::end(keyIds)));
         }
         return keyIds;
     });
 }
 
 bool Kleo::isRemoteKey(const GpgME::Key &key)
 {
     // a remote key looked up via WKD has key list mode Local; therefore we also look for the key in the local key ring
     return (key.keyListMode() == GpgME::Extern) || KeyCache::instance()->findByFingerprint(key.primaryFingerprint()).isNull();
 }
 
 GpgME::UserID::Validity Kleo::minimalValidityOfNotRevokedUserIDs(const Key &key)
 {
     const std::vector<UserID> userIDs = key.userIDs();
     const int minValidity = std::accumulate(userIDs.begin(), userIDs.end(), UserID::Ultimate + 1, [](int validity, const UserID &userID) {
         return userID.isRevoked() ? validity : std::min(validity, static_cast<int>(userID.validity()));
     });
     return minValidity <= UserID::Ultimate ? static_cast<UserID::Validity>(minValidity) : UserID::Unknown;
 }
 
 GpgME::UserID::Validity Kleo::maximalValidityOfUserIDs(const Key &key)
 {
     const auto userIDs = key.userIDs();
     const int maxValidity = std::accumulate(userIDs.begin(), userIDs.end(), 0, [](int validity, const UserID &userID) {
         return std::max(validity, static_cast<int>(userID.validity()));
     });
     return static_cast<UserID::Validity>(maxValidity);
 }
 
 bool Kleo::allUserIDsHaveFullValidity(const GpgME::Key &key)
 {
     return minimalValidityOfNotRevokedUserIDs(key) >= UserID::Full;
 }
 
 namespace
 {
 bool isLastValidUserID(const GpgME::UserID &userId)
 {
     if (Kleo::isRevokedOrExpired(userId)) {
         return false;
     }
     const auto userIds = userId.parent().userIDs();
     const int numberOfValidUserIds = std::count_if(std::begin(userIds), std::end(userIds), [](const auto &u) {
         return !Kleo::isRevokedOrExpired(u);
     });
     return numberOfValidUserIds == 1;
 }
 
 bool hasValidUserID(const GpgME::Key &key)
 {
     return Kleo::any_of(key.userIDs(), [](const auto &u) {
         return !Kleo::isRevokedOrExpired(u);
     });
 }
 }
 
 bool Kleo::isSelfSignature(const GpgME::UserID::Signature &signature)
 {
     return !qstrcmp(signature.parent().parent().keyID(), signature.signerKeyID());
 }
 
 bool Kleo::isRevokedOrExpired(const GpgME::UserID &userId)
 {
     if (userId.isRevoked() || userId.parent().isExpired()) {
         return true;
     }
     const auto sigs = userId.signatures();
     std::vector<GpgME::UserID::Signature> selfSigs;
     std::copy_if(std::begin(sigs), std::end(sigs), std::back_inserter(selfSigs), &Kleo::isSelfSignature);
     std::sort(std::begin(selfSigs), std::end(selfSigs));
     // check the most recent signature
     const auto sig = !selfSigs.empty() ? selfSigs.back() : GpgME::UserID::Signature{};
     return !sig.isNull() && (sig.isRevokation() || sig.isExpired());
 }
 
 bool Kleo::isExpired(const UserID &userID)
 {
     if (userID.parent().isExpired()) {
         return true;
     }
     const auto sigs = userID.signatures();
     std::vector<GpgME::UserID::Signature> selfSigs;
     std::copy_if(std::begin(sigs), std::end(sigs), std::back_inserter(selfSigs), &Kleo::isSelfSignature);
     std::sort(std::begin(selfSigs), std::end(selfSigs));
     // check the most recent signature
     const auto sig = !selfSigs.empty() ? selfSigs.back() : GpgME::UserID::Signature{};
     return !sig.isNull() && sig.isExpired();
 }
 
 bool Kleo::canCreateCertifications(const GpgME::Key &key)
 {
     return Kleo::keyHasCertify(key) && canBeUsedForSecretKeyOperations(key);
 }
 
 bool Kleo::canBeCertified(const GpgME::Key &key)
 {
     return key.protocol() == GpgME::OpenPGP //
         && !key.isBad() //
         && hasValidUserID(key);
 }
 
 namespace
 {
 static inline bool subkeyHasSecret(const GpgME::Subkey &subkey)
 {
 #if GPGME_VERSION_NUMBER >= 0x011102 // 1.17.2
     // we need to check the primary subkey because Key::hasSecret() is also true if just the secret key stub of an offline key is available
     return subkey.isSecret();
 #else
     // older versions of GpgME did not always set the secret flag for card keys
     return subkey.isSecret() || subkey.isCardKey();
 #endif
 }
 }
 
 bool Kleo::canBeUsedForEncryption(const GpgME::Key &key)
 {
     return !key.isBad() && Kleo::any_of(key.subkeys(), [](const auto &subkey) {
         return subkey.canEncrypt() && !subkey.isBad();
     });
 }
 
 bool Kleo::canBeUsedForSigning(const GpgME::Key &key)
 {
     return !key.isBad() && Kleo::any_of(key.subkeys(), [](const auto &subkey) {
         return subkey.canSign() && !subkey.isBad() && subkeyHasSecret(subkey);
     });
 }
 
 bool Kleo::canBeUsedForSecretKeyOperations(const GpgME::Key &key)
 {
     return subkeyHasSecret(key.subkey(0));
 }
 
 bool Kleo::canRevokeUserID(const GpgME::UserID &userId)
 {
     return (!userId.isNull() //
             && userId.parent().protocol() == GpgME::OpenPGP //
             && !isLastValidUserID(userId));
 }
 
 bool Kleo::isSecretKeyStoredInKeyRing(const GpgME::Key &key)
 {
     return key.subkey(0).isSecret() && !key.subkey(0).isCardKey();
 }
 
 bool Kleo::userHasCertificationKey()
 {
     const auto secretKeys = KeyCache::instance()->secretKeys();
     return Kleo::any_of(secretKeys, [](const auto &k) {
         return (k.protocol() == GpgME::OpenPGP) && canCreateCertifications(k);
     });
 }
 
 Kleo::CertificationRevocationFeasibility Kleo::userCanRevokeCertification(const GpgME::UserID::Signature &certification)
 {
     const auto certificationKey = KeyCache::instance()->findByKeyIDOrFingerprint(certification.signerKeyID());
     const bool isSelfSignature = qstrcmp(certification.parent().parent().keyID(), certification.signerKeyID()) == 0;
     if (!certificationKey.hasSecret()) {
         return CertificationNotMadeWithOwnKey;
     } else if (isSelfSignature) {
         return CertificationIsSelfSignature;
     } else if (certification.isRevokation()) {
         return CertificationIsRevocation;
     } else if (certification.isExpired()) {
         return CertificationIsExpired;
     } else if (certification.isInvalid()) {
         return CertificationIsInvalid;
     } else if (!canCreateCertifications(certificationKey)) {
         return CertificationKeyNotAvailable;
     }
     return CertificationCanBeRevoked;
 }
 
 bool Kleo::userCanRevokeCertifications(const GpgME::UserID &userId)
 {
     if (userId.numSignatures() == 0) {
         qCWarning(LIBKLEO_LOG) << __func__ << "- Error: Signatures of user ID" << QString::fromUtf8(userId.id()) << "not available";
     }
     return Kleo::any_of(userId.signatures(), [](const auto &certification) {
         return userCanRevokeCertification(certification) == CertificationCanBeRevoked;
     });
 }
 
 bool Kleo::userIDBelongsToKey(const GpgME::UserID &userID, const GpgME::Key &key)
 {
     return !qstricmp(userID.parent().primaryFingerprint(), key.primaryFingerprint());
 }
 
 static time_t creationDate(const GpgME::UserID &uid)
 {
     // returns the date of the first self-signature
     for (unsigned int i = 0, numSignatures = uid.numSignatures(); i < numSignatures; ++i) {
         const auto sig = uid.signature(i);
         if (Kleo::isSelfSignature(sig)) {
             return sig.creationTime();
         }
     }
     return 0;
 }
 
 bool Kleo::userIDsAreEqual(const GpgME::UserID &lhs, const GpgME::UserID &rhs)
 {
     return (qstrcmp(lhs.parent().primaryFingerprint(), rhs.parent().primaryFingerprint()) == 0 //
             && qstrcmp(lhs.id(), rhs.id()) == 0 //
             && creationDate(lhs) == creationDate(rhs));
 }
 
 static inline bool isOpenPGPCertification(const GpgME::UserID::Signature &sig)
 {
     // certification class is 0x10, ..., 0x13
     return (sig.certClass() & ~0x03) == 0x10;
 }
 
 static bool isOpenPGPCertificationByUser(const GpgME::UserID::Signature &sig)
 {
     if (!isOpenPGPCertification(sig)) {
         return false;
     }
     const auto certificationKey = KeyCache::instance()->findByKeyIDOrFingerprint(sig.signerKeyID());
     return certificationKey.ownerTrust() == Key::Ultimate;
 }
 
 bool Kleo::userIDIsCertifiedByUser(const GpgME::UserID &userId)
 {
     if (userId.parent().protocol() != GpgME::OpenPGP) {
         qCWarning(LIBKLEO_LOG) << __func__ << "not called with OpenPGP key";
         return false;
     }
     if (userId.numSignatures() == 0) {
         qCWarning(LIBKLEO_LOG) << __func__ << "- Error: Signatures of user ID" << QString::fromUtf8(userId.id()) << "not available";
     }
     for (unsigned int i = 0, numSignatures = userId.numSignatures(); i < numSignatures; ++i) {
         const auto sig = userId.signature(i);
         if ((sig.status() == UserID::Signature::NoError) && !sig.isBad() && sig.isExportable() && isOpenPGPCertificationByUser(sig)) {
             return true;
         }
     }
     return false;
 }