File indexing completed on 2024-05-19 05:26:26

 /*
     Copyright (c) 2009 Constantin Berzan <exit3219@gmail.com>
     Copyright (C) 2010 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com
     Copyright (c) 2010 Leo Franchi <lfranchi@kde.org>
     Copyright (c) 2017 Christian Mollekopf <mollekopf@kolabsys.com>
 
     This library is free software; you can redistribute it and/or modify it
     under the terms of the GNU Library General Public License as published by
     the Free Software Foundation; either version 2 of the License, or (at your
     option) any later version.
 
     This library 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 Library General Public
     License for more details.
 
     You should have received a copy of the GNU Library General Public License
     along with this library; see the file COPYING.LIB.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
     02110-1301, USA.
 */
 #include "crypto.h"
 
 #include "errors.h"
 
 #include <gpgme.h>
 
 #include <QDebug>
 #include <QDateTime>
 #include <QFile>
 
 #include <future>
 #include <utility>
 
 using namespace Crypto;
 
 QDebug operator<< (QDebug d, const Key &key)
 {
     d << key.fingerprint;
     return d;
 }
 
 QDebug operator<< (QDebug d, const Error &error)
 {
     d << error.error;
     return d;
 }
 
 namespace Crypto {
     struct Data {
         Data(const QByteArray &buffer)
         {
             const bool copy = false;
             const gpgme_error_t e = gpgme_data_new_from_mem(&data, buffer.constData(), buffer.size(), int(copy));
             if (e) {
                 qWarning() << "Failed to copy data?" << e;
             }
         }
 
         ~Data()
         {
             gpgme_data_release(data);
         }
         gpgme_data_t data;
     };
 }
 
 static gpgme_error_t checkEngine(CryptoProtocol protocol)
 {
     gpgme_check_version(0);
     const gpgme_protocol_t p = protocol == CMS ? GPGME_PROTOCOL_CMS : GPGME_PROTOCOL_OpenPGP;
     return gpgme_engine_check_version(p);
 }
 
 static std::pair<gpgme_error_t, gpgme_ctx_t> createForProtocol(CryptoProtocol proto)
 {
     if (auto e = checkEngine(proto)) {
         qWarning() << "GPG Engine check failed." << e;
         return std::make_pair(e, nullptr);
     }
     gpgme_ctx_t ctx = 0;
     if (auto e = gpgme_new(&ctx)) {
         return std::make_pair(e, nullptr);
     }
 
     switch (proto) {
         case OpenPGP:
             if (auto e = gpgme_set_protocol(ctx, GPGME_PROTOCOL_OpenPGP)) {
                 gpgme_release(ctx);
                 return std::make_pair(e, nullptr);
             }
         break;
         case CMS:
             if (auto e = gpgme_set_protocol(ctx, GPGME_PROTOCOL_CMS)) {
                 gpgme_release(ctx);
                 return std::make_pair(e, nullptr);
             }
         break;
         default:
             Q_ASSERT(false);
             return std::make_pair(1, nullptr);
     }
 
     //We want the output to always be ASCII armored
     gpgme_set_armor(ctx, 1);
 
     //Trust new keys
     if (auto e = gpgme_set_ctx_flag(ctx, "trust-model", "tofu+pgp")) {
         gpgme_release(ctx);
         return std::make_pair(e, nullptr);
     }
 
     //That's a great way to bring signature verification to a crawl
     if (auto e = gpgme_set_ctx_flag(ctx, "auto-key-retrieve", "0")) {
         gpgme_release(ctx);
         return std::make_pair(e, nullptr);
     }
 
     return std::make_pair(GPG_ERR_NO_ERROR, ctx);
 }
 
 gpgme_error_t gpgme_passphrase(void *hook, const char *uid_hint, const char *passphrase_info, int prev_was_bad, int fd)
 {
     Q_UNUSED(hook);
     Q_UNUSED(prev_was_bad);
     //uid_hint will be something like "CAA5183608F0FB50 Test1 Kolab <test1@kolab.org>" (CAA518... is the key)
     //pahhphrase_info will be something like "CAA5183608F0FB50 2E3B7787B1B75920 1 0"
     qInfo() << "Requested passphrase for " << (uid_hint ? QByteArray{uid_hint} : QByteArray{}) << (passphrase_info ? QByteArray{passphrase_info} : QByteArray{});
 
     QFile file;
     file.open(fd, QIODevice::WriteOnly);
     //FIXME hardcoded as a test
     auto passphrase = QByteArray{"test1"} + QByteArray{"\n"};
     file.write(passphrase);
     file.close();
 
     return 0;
 }
 
 
 namespace Crypto {
 struct Context {
     Context(CryptoProtocol protocol = OpenPGP)
     {
         gpgme_error_t code;
         std::tie(code, context) = createForProtocol(protocol);
         error = Error{code};
         //For enabling the loopback passphrase
         //if (!error) {
         //    gpgme_set_passphrase_cb (context, gpgme_passphrase, 0);
         //    //TODO requires allow-loopback-pinentry to be enabled in the gpg-agent.conf
         //    gpgme_set_pinentry_mode(context, GPGME_PINENTRY_MODE_LOOPBACK);
         //}
     }
 
     ~Context()
     {
         gpgme_release(context);
     }
 
     operator bool() const
     {
         return !error;
     }
     Error error;
     gpgme_ctx_t context;
 };
 }
 
 
 static QByteArray toBA(gpgme_data_t out)
 {
     size_t length = 0;
     auto data = gpgme_data_release_and_get_mem (out, &length);
     auto outdata = QByteArray{data, static_cast<int>(length)};
     gpgme_free(data);
     return outdata;
 }
 
 static std::vector<Recipient> copyRecipients(gpgme_decrypt_result_t result)
 {
     std::vector<Recipient> recipients;
     for (gpgme_recipient_t r = result->recipients ; r ; r = r->next) {
         recipients.push_back({QByteArray{r->keyid}, r->status != GPG_ERR_NO_SECKEY});
     }
     return recipients;
 }
 
 static std::vector<Signature> copySignatures(gpgme_verify_result_t result)
 {
     std::vector<Signature> signatures;
     for (gpgme_signature_t is = result->signatures ; is ; is = is->next) {
         Signature sig;
         sig.fingerprint = QByteArray{is->fpr};
         sig.creationTime.setTime_t(is->timestamp);
         if (is->summary & GPGME_SIGSUM_VALID) {
             sig.result = Signature::Ok;
         } else {
             sig.result = Signature::Invalid;
             if (is->summary & GPGME_SIGSUM_KEY_EXPIRED) {
                 sig.result = Signature::Expired;
             }
             if (is->summary & GPGME_SIGSUM_KEY_MISSING) {
                 sig.result = Signature::KeyNotFound;
             }
         }
         sig.status = {is->status};
         sig.isTrusted = is->validity == GPGME_VALIDITY_FULL || is->validity == GPGME_VALIDITY_ULTIMATE;
         signatures.push_back(sig);
     }
     return signatures;
 }
 
 
 VerificationResult Crypto::verifyDetachedSignature(CryptoProtocol protocol, const QByteArray &signature, const QByteArray &text)
 {
     Context context{protocol};
     if (!context) {
         qWarning() << "Failed to create context " << context.error;
         return {{}, context.error};
     }
     auto ctx = context.context;
 
     auto err = gpgme_op_verify(ctx, Data{signature}.data, Data{text}.data, 0);
     gpgme_verify_result_t res = gpgme_op_verify_result(ctx);
     return {copySignatures(res), {err}};
 }
 
 VerificationResult Crypto::verifyOpaqueSignature(CryptoProtocol protocol, const QByteArray &signature, QByteArray &outdata)
 {
     Context context{protocol};
     if (!context) {
         qWarning() << "Failed to create context " << context.error;
         return VerificationResult{{}, context.error};
     }
     auto ctx = context.context;
 
     gpgme_data_t out;
     const gpgme_error_t e = gpgme_data_new(&out);
     Q_ASSERT(!e);
     auto err = gpgme_op_verify(ctx, Data{signature}.data, 0, out);
 
     VerificationResult result{{}, {err}};
     if (gpgme_verify_result_t res = gpgme_op_verify_result(ctx)) {
         result.signatures = copySignatures(res);
     }
 
     outdata = toBA(out);
     return result;
 }
 
 static DecryptionResult::Result toResult(gpgme_error_t err)
 {
     if (err == GPG_ERR_NO_DATA) {
         return DecryptionResult::NotEncrypted;
     } else if (err == GPG_ERR_NO_SECKEY) {
         return DecryptionResult::NoSecretKeyError;
     } else if (err == GPG_ERR_CANCELED || err == GPG_ERR_INV_PASSPHRASE) {
         return DecryptionResult::PassphraseError;
     }
     qWarning() << "unknown error" << err << gpgme_strerror(err);
     return DecryptionResult::NoSecretKeyError;
 }
 
 std::pair<DecryptionResult,VerificationResult> Crypto::decryptAndVerify(CryptoProtocol protocol, const QByteArray &ciphertext, QByteArray &outdata)
 {
     Context context{protocol};
     if (!context) {
         qWarning() << "Failed to create context " << gpgme_strerror(context.error);
         qWarning() << "returning early";
         return std::make_pair(DecryptionResult{{}, {context.error}, DecryptionResult::NoSecretKeyError}, VerificationResult{{}, context.error});
     }
     auto ctx = context.context;
 
     gpgme_data_t out;
     if (gpgme_error_t e = gpgme_data_new(&out)) {
         qWarning() << "Failed to allocated data" << e;
     }
     auto err = gpgme_op_decrypt_verify(ctx, Data{ciphertext}.data, out);
     if (err) {
         qWarning() << "Failed to decrypt and verify" << Error{err};
         //We make sure we don't return any plain-text if the decryption failed to prevent EFAIL
         if (err == GPG_ERR_DECRYPT_FAILED) {
             return std::make_pair(DecryptionResult{{}, {err}, DecryptionResult::DecryptionError}, VerificationResult{{}, {err}});
         }
     }
 
     VerificationResult verificationResult{{}, {err}};
     if (gpgme_verify_result_t res = gpgme_op_verify_result(ctx)) {
         verificationResult.signatures = copySignatures(res);
     }
 
     DecryptionResult decryptionResult{{}, {err}};
     if (gpgme_decrypt_result_t res = gpgme_op_decrypt_result(ctx)) {
         decryptionResult.recipients = copyRecipients(res);
     }
     decryptionResult.result = toResult(err);
 
     outdata = toBA(out);
     return std::make_pair(decryptionResult, verificationResult);
 }
 
 static DecryptionResult decryptGPGME(CryptoProtocol protocol, const QByteArray &ciphertext, QByteArray &outdata)
 {
     Context context{protocol};
     if (!context) {
         qWarning() << "Failed to create context " << context.error;
         return DecryptionResult{{}, context.error};
     }
     auto ctx = context.context;
 
     gpgme_data_t out;
     if (gpgme_error_t e = gpgme_data_new(&out)) {
         qWarning() << "Failed to allocated data" << e;
     }
     auto err = gpgme_op_decrypt(ctx, Data{ciphertext}.data, out);
     if (err) {
         qWarning() << "Failed to decrypt" << gpgme_strerror(err);
         //We make sure we don't return any plain-text if the decryption failed to prevent EFAIL
         if (err == GPG_ERR_DECRYPT_FAILED) {
             return DecryptionResult{{}, {err}};
         }
     }
 
     DecryptionResult decryptionResult{{}, {err}};
     if (gpgme_decrypt_result_t res = gpgme_op_decrypt_result(ctx)) {
         decryptionResult.recipients = copyRecipients(res);
     }
 
     decryptionResult.result = toResult(err);
 
     outdata = toBA(out);
     return decryptionResult;
 }
 
 DecryptionResult Crypto::decrypt(CryptoProtocol protocol, const QByteArray &ciphertext, QByteArray &outdata)
 {
         return decryptGPGME(protocol, ciphertext, outdata);
 }
 
 ImportResult Crypto::importKey(CryptoProtocol protocol, const QByteArray &certData)
 {
     Context context{protocol};
     if (!context) {
         qWarning() << "Failed to create context " << context.error;
         return {0, 0, 0};
     }
     if (gpgme_op_import(context.context, Data{certData}.data)) {
         qWarning() << "Import failed";
         return {0, 0, 0};
     }
     if (auto result = gpgme_op_import_result(context.context)) {
         return {result->considered, result->imported, result->unchanged};
     } else {
         return {0, 0, 0};
     }
 }
 
 static bool validateKey(const gpgme_key_t key)
 {
     if (key->revoked) {
         qWarning() << "Key is revoked " << key->fpr;
         return false;
     }
     if (key->expired) {
         qWarning() << "Key is expired " << key->fpr;
         return false;
     }
     if (key->disabled) {
         qWarning() << "Key is disabled " << key->fpr;
         return false;
     }
     if (key->invalid) {
         qWarning() << "Key is invalid " << key->fpr;
         return false;
     }
     return true;
 }
 
 
 static KeyListResult listKeys(CryptoProtocol protocol, const std::vector<const char*> &patterns, bool secretOnly, int keyListMode, bool importKeys)
 {
     Context context{protocol};
     if (!context) {
         qWarning() << "Failed to create context " << context.error;
         return {{}, context.error};
     }
     auto ctx = context.context;
 
     gpgme_set_keylist_mode(ctx, keyListMode);
 
     KeyListResult result;
     result.error = {GPG_ERR_NO_ERROR};
     auto zeroTerminatedPatterns = patterns;
     zeroTerminatedPatterns.push_back(0);
     if (patterns.size() > 1) {
         if (auto err = gpgme_op_keylist_ext_start(ctx, const_cast<const char **>(zeroTerminatedPatterns.data()), int(secretOnly), 0)) {
             result.error = {err};
             qWarning() << "Error while listing keys:" << result.error;
         }
     } else if (patterns.size() == 1) {
         if (auto err = gpgme_op_keylist_start(ctx, zeroTerminatedPatterns[0], int(secretOnly))) {
             result.error = {err};
             qWarning() << "Error while listing keys:" << result.error;
         }
     } else {
         if (auto err = gpgme_op_keylist_start(ctx, 0, int(secretOnly))) {
             result.error = {err};
             qWarning() << "Error while listing keys:" << result.error;
         }
     }
 
 
     std::vector<gpgme_key_t> listedKeys;
     while (true) {
         gpgme_key_t key;
         if (auto err = gpgme_op_keylist_next(ctx, &key)) {
             if (gpgme_err_code(err) != GPG_ERR_EOF) {
                 qWarning() << "Error after listing keys" << result.error << gpgme_strerror(err);
             }
             break;
         }
 
         listedKeys.push_back(key);
 
         Key k;
         if (key->subkeys) {
             k.keyId = QByteArray{key->subkeys->keyid};
             k.shortKeyId = k.keyId.right(8);
             k.fingerprint = QByteArray{key->subkeys->fpr};
         }
         for (gpgme_user_id_t uid = key->uids ; uid ; uid = uid->next) {
             k.userIds.push_back(UserId{QByteArray{uid->name}, QByteArray{uid->email}, QByteArray{uid->uid}});
         }
         k.isUsable = validateKey(key);
         result.keys.push_back(k);
     }
     gpgme_op_keylist_end(ctx);
 
     if (importKeys && !listedKeys.empty()) {
         listedKeys.push_back(0);
         if (auto err = gpgme_op_import_keys(ctx, const_cast<gpgme_key_t*>(listedKeys.data()))) {
             qWarning() << "Error while importing keys" << gpgme_strerror(err);
         }
     }
     return result;
 }
 
 /**
  * Get the given `key` in the armor format.
  */
 Expected<Error, QByteArray> Crypto::exportPublicKey(const Key &key)
 {
     Context context;
     if (!context) {
         return makeUnexpected(Error{context.error});
     }
 
     gpgme_data_t out;
     const gpgme_error_t e = gpgme_data_new(&out);
     Q_ASSERT(!e);
 
     qDebug() << "Exporting public key:" << key.keyId;
     if (auto err = gpgme_op_export(context.context, key.keyId, 0, out)) {
         return makeUnexpected(Error{err});
     }
 
     return toBA(out);
 }
 
 Expected<Error, QByteArray> Crypto::signAndEncrypt(const QByteArray &content, const std::vector<Key> &encryptionKeys, const std::vector<Key> &signingKeys)
 {
     Context context;
     if (!context) {
         return makeUnexpected(Error{context.error});
     }
 
     for (const auto &signingKey : signingKeys) {
         qDebug() << "Signing with " << signingKey;
         //TODO do we have to free those again?
         gpgme_key_t key;
         if (auto e = gpgme_get_key(context.context, signingKey.fingerprint, &key, /*secret*/ false)) {
             qWarning() << "Failed to retrieve signing key " << signingKey.fingerprint << Error{e};
             return makeUnexpected(Error{e});
         } else {
             if (!key->can_sign || !validateKey(key)) {
                 qWarning() << "Key cannot be used for signing " << key->fpr;
                 return makeUnexpected(Error{e});
             }
             gpgme_signers_add(context.context, key);
         }
     }
 
     gpgme_key_t * const keys = new gpgme_key_t[encryptionKeys.size() + 1];
     gpgme_key_t * keys_it = keys;
     for (const auto &k : encryptionKeys) {
         qDebug() << "Encrypting to " << k;
         gpgme_key_t key;
         if (auto e = gpgme_get_key(context.context, k.fingerprint, &key, /*secret*/ false)) {
             qWarning() << "Failed to retrieve key " << k.fingerprint << Error{e};
             delete[] keys;
             return makeUnexpected(Error{e});
         } else {
             if (!key->can_encrypt || !validateKey(key)) {
                 qWarning() << "Key cannot be used for encryption " << k.fingerprint;
                 delete[] keys;
                 return makeUnexpected(Error{e});
             }
             *keys_it++ = key;
         }
     }
     *keys_it++ = 0;
 
     gpgme_data_t out;
     if (auto e = gpgme_data_new(&out)) {
         qWarning() << "Failed to allocate output buffer";
         delete[] keys;
         return makeUnexpected(Error{e});
     }
 
     gpgme_error_t err = !signingKeys.empty() ?
         gpgme_op_encrypt_sign(context.context, keys, GPGME_ENCRYPT_ALWAYS_TRUST, Data{content}.data, out) :
         gpgme_op_encrypt(context.context, keys, GPGME_ENCRYPT_ALWAYS_TRUST, Data{content}.data, out);
     delete[] keys;
     if (err) {
         qWarning() << "Encryption failed:" << gpgme_strerror(err);
         switch (gpgme_err_code(err)) {
             case GPG_ERR_UNUSABLE_PUBKEY:
                 for (const auto &k : encryptionKeys) {
                     qWarning() << "Encryption key:" << k;
                 }
                 break;
             case GPG_ERR_UNUSABLE_SECKEY:
                 for (const auto &k : signingKeys) {
                     qWarning() << "Signing key:" << k;
                 }
                 break;
             default:
                 break;
         }
         return makeUnexpected(Error{err});
     }
 
     return toBA(out);
 }
 
 Expected<Error, std::pair<QByteArray, QString>>
 Crypto::sign(const QByteArray &content, const std::vector<Key> &signingKeys)
 {
     Context context;
     if (!context) {
         return makeUnexpected(Error{context.error});
     }
 
     for (const auto &signingKey : signingKeys) {
         //TODO do we have to free those again?
         gpgme_key_t key;
         if (auto e = gpgme_get_key(context.context, signingKey.fingerprint, &key, /*secret*/ false)) {
             qWarning() << "Failed to retrieve signing key " << signingKey.fingerprint << Error{e};
             return makeUnexpected(Error{e});
         } else {
             gpgme_signers_add(context.context, key);
         }
     }
 
     gpgme_data_t out;
     const gpgme_error_t e = gpgme_data_new(&out);
     Q_ASSERT(!e);
 
     if (auto err = gpgme_op_sign(context.context, Data{content}.data, out, GPGME_SIG_MODE_DETACH)) {
         qWarning() << "Signing failed:" << Error{err};
         return makeUnexpected(Error{err});
     }
 
 
     const QByteArray algo = [&] {
         if (gpgme_sign_result_t res = gpgme_op_sign_result(context.context)) {
             if (gpgme_new_signature_t is = res->signatures) {
                 return QByteArray{gpgme_hash_algo_name(is->hash_algo)};
             }
         }
         return QByteArray{};
     }();
     // RFC 3156 Section 5:
     // Hash-symbols are constructed [...] by converting the text name to lower
     // case and prefixing it with the four characters "pgp-".
     const auto micAlg = (QString("pgp-") + algo).toLower();
 
     return std::pair<QByteArray, QString>{toBA(out), micAlg};
 }
 
 std::vector<Key> Crypto::findKeys(const QStringList &patterns, bool findPrivate, bool remote)
 {
     QByteArrayList list;
     std::transform(patterns.constBegin(), patterns.constEnd(), std::back_inserter(list), [] (const QString &s) { return s.toUtf8(); });
     std::vector<char const *> pattern;
     std::transform(list.constBegin(), list.constEnd(), std::back_inserter(pattern), [] (const QByteArray &s) { return s.constData(); });
 
     const KeyListResult res = listKeys(OpenPGP, pattern, findPrivate, remote ? GPGME_KEYLIST_MODE_EXTERN : GPGME_KEYLIST_MODE_LOCAL, remote);
     if (res.error) {
         qWarning() << "Failed to lookup keys: " << res.error;
         return {};
     }
     qDebug() << "Found " << res.keys.size() << " keys for the patterns: " << patterns;
 
     std::vector<Key> usableKeys;
     for (const auto &key : res.keys) {
         if (!key.isUsable) {
             qWarning() <<  "Key is not usable: " << key.fingerprint;
             continue;
         }
 
         qDebug() << "Key:" << key.fingerprint;
         for (const auto &userId : key.userIds) {
             qDebug() << "  userID:" << userId.email;
         }
         usableKeys.push_back(key);
     }
     return usableKeys;
 }