cpp: Add interactor to revoke a key

* lang/cpp/src/global.h (enum class RevocationReason): New.
* lang/cpp/src/gpgrevokekeyeditinteractor.cpp,
lang/cpp/src/gpgrevokekeyeditinteractor.h: New.
* lang/cpp/src/Makefile.am: Add new files.
--

GnuPG-bug-id: 5904

NEWS

@@ -5,6 +5,13 @@ Noteworthy changes in version 1.17.2 (unreleased)
 
  * cpp, qt: Do not export internal symbols anymore.  [T5906]
 
+ * cpp: Support revocation of own OpenPGP keys.  [#5904]
+
+ * Interface changes relative to the 1.17.1 release:
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ cpp: RevocationReason                      NEW.
+ cpp: GpgRevokeKeyEditInteractor            NEW.
+
 
 Noteworthy changes in version 1.17.1 (2022-03-06)
 -------------------------------------------------

lang/cpp/src/Makefile.am

@@ -34,6 +34,7 @@ main_sources = \
     gpgsetownertrusteditinteractor.cpp gpgsignkeyeditinteractor.cpp \
     gpgadduserideditinteractor.cpp gpggencardkeyinteractor.cpp \
     gpgaddexistingsubkeyeditinteractor.cpp \
+    gpgrevokekeyeditinteractor.cpp \
     defaultassuantransaction.cpp \
     scdgetinfoassuantransaction.cpp gpgagentgetinfoassuantransaction.cpp \
     statusconsumerassuantransaction.cpp \
@@ -49,6 +50,7 @@ gpgmepp_headers = \
     gpgsetownertrusteditinteractor.h gpgsignkeyeditinteractor.h \
     gpggencardkeyinteractor.h \
     gpgaddexistingsubkeyeditinteractor.h \
+    gpgrevokekeyeditinteractor.h \
     importresult.h keygenerationresult.h key.h keylistresult.h \
     notation.h result.h scdgetinfoassuantransaction.h signingresult.h \
     statusconsumerassuantransaction.h \

lang/cpp/src/global.h

@@ -72,6 +72,13 @@ enum KeyListMode {
 
 enum SignatureMode { NormalSignatureMode, Detached, Clearsigned };
 
+enum class RevocationReason {
+    Unspecified = 0,
+    Compromised = 1,
+    Superseded = 2,
+    NoLongerUsed = 3
+};
+
 GPGMEPP_EXPORT std::ostream &operator<<(std::ostream &os, Protocol proto);
 GPGMEPP_EXPORT std::ostream &operator<<(std::ostream &os, Engine eng);
 GPGMEPP_EXPORT std::ostream &operator<<(std::ostream &os, KeyListMode mode);

lang/cpp/src/gpgrevokekeyeditinteractor.cpp

@@ -0,0 +1,212 @@
+/*
+  gpgrevokekeyeditinteractor.cpp - Edit Interactor to revoke own OpenPGP keys
+  Copyright (c) 2022 g10 Code GmbH
+  Software engineering by Ingo Klöcker <dev@ingo-kloecker.de>
+
+  This file is part of GPGME++.
+
+  GPGME++ 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.
+
+  GPGME++ 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 GPGME++; see the file COPYING.LIB.  If not, write to the
+  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+  Boston, MA 02110-1301, USA.
+*/
+
+#ifdef HAVE_CONFIG_H
+ #include "config.h"
+#endif
+
+#include "gpgrevokekeyeditinteractor.h"
+
+#include "error.h"
+
+#include <gpgme.h>
+
+#include <sstream>
+#include <vector>
+
+// avoid conflict (msvc)
+#ifdef ERROR
+# undef ERROR
+#endif
+
+using namespace GpgME;
+
+class GpgRevokeKeyEditInteractor::Private
+{
+    enum {
+        START = EditInteractor::StartState,
+        COMMAND,
+        CONFIRM_REVOKING_ENTIRE_KEY,
+        REASON_CODE,
+        REASON_TEXT,
+        // all these free slots belong to REASON_TEXT, too; we increase state()
+        // by one for each line of text, so that action() is called
+        REASON_TEXT_DONE = REASON_TEXT + 1000,
+        CONFIRM_REASON,
+        QUIT,
+        CONFIRM_SAVE,
+
+        ERROR = EditInteractor::ErrorState
+    };
+
+    GpgRevokeKeyEditInteractor *const q = nullptr;
+
+public:
+    Private(GpgRevokeKeyEditInteractor *q)
+        : q{q}
+        , reasonCode{"0"}
+    {
+    }
+
+    const char *action(Error &err) const;
+    unsigned int nextState(unsigned int statusCode, const char *args, Error &err);
+
+    std::string reasonCode;
+    std::vector<std::string> reasonLines;
+    int nextLine = -1;
+};
+
+const char *GpgRevokeKeyEditInteractor::Private::action(Error &err) const
+{
+    switch (const auto state = q->state()) {
+    case COMMAND:
+        return "revkey";
+    case CONFIRM_REVOKING_ENTIRE_KEY:
+        return "Y";
+    case REASON_CODE:
+        return reasonCode.c_str();
+    case REASON_TEXT_DONE:
+        return "";
+    case CONFIRM_REASON:
+        return "Y";
+    case QUIT:
+        return "quit";
+    case CONFIRM_SAVE:
+        return "Y";
+    case START:
+        return nullptr;
+    default:
+        if (state >= REASON_TEXT && state < REASON_TEXT_DONE) {
+            return reasonLines[nextLine].c_str();
+        }
+    // fall through
+    case ERROR:
+        err = Error::fromCode(GPG_ERR_GENERAL);
+        return nullptr;
+    }
+}
+
+unsigned int GpgRevokeKeyEditInteractor::Private::nextState(unsigned int status, const char *args, Error &err)
+{
+    using std::strcmp;
+
+    static const Error GENERAL_ERROR = Error::fromCode(GPG_ERR_GENERAL);
+
+    if (q->needsNoResponse(status)) {
+        return q->state();
+    }
+
+    switch (const auto state = q->state()) {
+    case START:
+        if (status == GPGME_STATUS_GET_LINE &&
+                strcmp(args, "keyedit.prompt") == 0) {
+            return COMMAND;
+        }
+        err = GENERAL_ERROR;
+        return ERROR;
+    case COMMAND:
+        if (status == GPGME_STATUS_GET_BOOL &&
+                strcmp(args, "keyedit.revoke.subkey.okay") == 0) {
+            return CONFIRM_REVOKING_ENTIRE_KEY;
+        }
+        err = GENERAL_ERROR;
+        return ERROR;
+    case CONFIRM_REVOKING_ENTIRE_KEY:
+        if (status == GPGME_STATUS_GET_LINE &&
+                strcmp(args, "ask_revocation_reason.code") == 0) {
+            return REASON_CODE;
+        }
+        err = GENERAL_ERROR;
+        return ERROR;
+    case REASON_CODE:
+        if (status == GPGME_STATUS_GET_LINE &&
+                strcmp(args, "ask_revocation_reason.text") == 0) {
+            nextLine++;
+            return nextLine < reasonLines.size() ? REASON_TEXT : REASON_TEXT_DONE;
+        }
+        err = GENERAL_ERROR;
+        return ERROR;
+    default:
+        if (state >= REASON_TEXT && state < REASON_TEXT_DONE) {
+            if (status == GPGME_STATUS_GET_LINE &&
+                    strcmp(args, "ask_revocation_reason.text") == 0) {
+                nextLine++;
+                return nextLine < reasonLines.size() ? state + 1 : REASON_TEXT_DONE;
+            }
+        }
+        err = GENERAL_ERROR;
+        return ERROR;
+    case REASON_TEXT_DONE:
+        if (status == GPGME_STATUS_GET_BOOL &&
+                strcmp(args, "ask_revocation_reason.okay") == 0) {
+            return CONFIRM_REASON;
+        }
+        err = GENERAL_ERROR;
+        return ERROR;
+    case CONFIRM_REASON:
+        if (status == GPGME_STATUS_GET_LINE &&
+                strcmp(args, "keyedit.prompt") == 0) {
+            return QUIT;
+        }
+        err = GENERAL_ERROR;
+        return ERROR;
+    case QUIT:
+        if (status == GPGME_STATUS_GET_BOOL &&
+                strcmp(args, "keyedit.save.okay") == 0) {
+            return CONFIRM_SAVE;
+        }
+        err = GENERAL_ERROR;
+        return ERROR;
+    case ERROR:
+        if (status == GPGME_STATUS_GET_LINE &&
+                strcmp(args, "keyedit.prompt") == 0) {
+            return QUIT;
+        }
+        err = q->lastError();
+        return ERROR;
+    }
+}
+
+GpgRevokeKeyEditInteractor::GpgRevokeKeyEditInteractor()
+    : EditInteractor{}
+    , d{new Private{this}}
+{
+}
+
+GpgRevokeKeyEditInteractor::~GpgRevokeKeyEditInteractor() = default;
+
+void GpgRevokeKeyEditInteractor::setReason(RevocationReason reason, const std::vector<std::string> &description)
+{
+    d->reasonCode = std::to_string(static_cast<int>(reason));
+    d->reasonLines = description;
+}
+
+const char *GpgRevokeKeyEditInteractor::action(Error &err) const
+{
+    return d->action(err);
+}
+
+unsigned int GpgRevokeKeyEditInteractor::nextState(unsigned int status, const char *args, Error &err) const
+{
+    return d->nextState(status, args, err);
+}

lang/cpp/src/gpgrevokekeyeditinteractor.h

@@ -0,0 +1,62 @@
+/*
+  gpgrevokekeyeditinteractor.h - Edit Interactor to revoke own OpenPGP keys
+  Copyright (c) 2022 g10 Code GmbH
+  Software engineering by Ingo Klöcker <dev@ingo-kloecker.de>
+
+  This file is part of GPGME++.
+
+  GPGME++ 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.
+
+  GPGME++ 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 GPGME++; see the file COPYING.LIB.  If not, write to the
+  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+  Boston, MA 02110-1301, USA.
+*/
+
+#ifndef __GPGMEPP_GPGREVOKEKEYEDITINTERACTOR_H__
+#define __GPGMEPP_GPGREVOKEKEYEDITINTERACTOR_H__
+
+#include "editinteractor.h"
+#include "global.h"
+
+#include <memory>
+#include <vector>
+
+namespace GpgME
+{
+
+/** Edit interactor to revoke the key a key edit operation is working on.
+ *  Supports revocation of own keys only. */
+class GPGMEPP_EXPORT GpgRevokeKeyEditInteractor : public EditInteractor
+{
+public:
+    GpgRevokeKeyEditInteractor();
+    ~GpgRevokeKeyEditInteractor() override;
+
+    /** Sets the reason for the revocation. The reason defaults to \c Unspecified.
+     *  \a description can be used for adding a comment for the revocation. The
+     *  individual elements of \a description must be non-empty strings and they
+     *  must not contain any endline characters.
+     */
+    void setReason(RevocationReason reason, const std::vector<std::string> &description = {});
+
+private:
+    const char *action(Error &err) const override;
+    unsigned int nextState(unsigned int statusCode, const char *args, Error &err) const override;
+
+private:
+    class Private;
+    const std::unique_ptr<Private> d;
+};
+
+} // namespace GpgME
+
+#endif // __GPGMEPP_GPGREVOKEKEYEDITINTERACTOR_H__