SSH Agent: Show error messages if something fails

src/gui/MainWindow.cpp

@@ -198,6 +198,7 @@ MainWindow::MainWindow()
 #endif
 #ifdef WITH_XC_SSHAGENT
     SSHAgent::init(this);
+    connect(SSHAgent::instance(), SIGNAL(error(QString)), this, SLOT(showErrorMessage(QString)));
     m_ui->settingsWidget->addSettingsPage(new AgentSettingsPage(m_ui->tabWidget));
 #endif
 
@@ -454,6 +455,11 @@ void MainWindow::showKeePassHTTPDeprecationNotice()
     disconnect(m_ui->globalMessageWidget, SIGNAL(hideAnimationFinished()), this, SLOT(showKeePassHTTPDeprecationNotice()));
 }
 
+void MainWindow::showErrorMessage(const QString& message)
+{
+    m_ui->globalMessageWidget->showMessage(message, MessageWidget::Error);
+}
+
 void MainWindow::appExit()
 {
     m_appExitCalled = true;

src/gui/MainWindow.h

@@ -104,6 +104,7 @@ private slots:
     void hideTabMessage();
     void handleScreenLock();
     void showKeePassHTTPDeprecationNotice();
+    void showErrorMessage(const QString& message);
 
 private:
     static void setShortcut(QAction* action, QKeySequence::StandardKey standard, int fallback = 0);

src/gui/entry/EditEntryWidget.cpp

@@ -485,7 +485,10 @@ void EditEntryWidget::addKeyToAgent()
         lifetime = m_sshAgentUi->lifetimeSpinBox->value();
     }
 
-    SSHAgent::instance()->addIdentity(key, lifetime, confirm);
+    if (!SSHAgent::instance()->addIdentity(key, lifetime, confirm)) {
+        showMessage(SSHAgent::instance()->errorString(), MessageWidget::Error);
+        return;
+    }
 
     if (m_sshAgentUi->removeKeyFromAgentCheckBox->isChecked()) {
         SSHAgent::instance()->removeIdentityAtLock(key, m_entry->uuid());
@@ -496,8 +499,13 @@ void EditEntryWidget::removeKeyFromAgent()
 {
     OpenSSHKey key;
 
-    if (getOpenSSHKey(key)) {
+    if (!getOpenSSHKey(key)) {
-        SSHAgent::instance()->removeIdentity(key);
+        return;
+    }
+
+    if (!SSHAgent::instance()->removeIdentity(key)) {
+        showMessage(SSHAgent::instance()->errorString(), MessageWidget::Error);
+        return;
     }
 }
 

src/sshagent/SSHAgent.cpp

@@ -58,6 +58,11 @@ void SSHAgent::init(QObject* parent)
     m_instance = new SSHAgent(parent);
 }
 
+const QString SSHAgent::errorString() const
+{
+    return m_error;
+}
+
 bool SSHAgent::isAgentRunning() const
 {
 #ifndef Q_OS_WIN
@@ -67,7 +72,7 @@ bool SSHAgent::isAgentRunning() const
 #endif
 }
 
-bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out) const
+bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out)
 {
 #ifndef Q_OS_WIN
     QLocalSocket socket;
@@ -75,6 +80,7 @@ bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out) const
 
     socket.connectToServer(m_socketPath);
     if (!socket.waitForConnected(500)) {
+        m_error = tr("Agent connection failed.");
         return false;
     }
 
@@ -82,6 +88,7 @@ bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out) const
     stream.flush();
 
     if (!stream.readString(out)) {
+        m_error = tr("Agent protocol error.");
         return false;
     }
 
@@ -92,10 +99,12 @@ bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out) const
     HWND hWnd = FindWindowA("Pageant", "Pageant");
 
     if (!hWnd) {
+        m_error = tr("Agent connection failed.");
         return false;
     }
 
     if (static_cast<quint32>(in.length()) > AGENT_MAX_MSGLEN - 4) {
+        m_error = tr("Agent connection failed.");
         return false;
     }
 
@@ -104,6 +113,7 @@ bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out) const
     HANDLE handle = CreateFileMappingA(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, AGENT_MAX_MSGLEN, mapName.data());
 
     if (!handle) {
+        m_error = tr("Agent connection failed.");
         return false;
     }
 
@@ -111,6 +121,7 @@ bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out) const
 
     if (!ptr) {
         CloseHandle(handle);
+        m_error = tr("Agent connection failed.");
         return false;
     }
 
@@ -132,7 +143,11 @@ bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out) const
         if (responseLength <= AGENT_MAX_MSGLEN) {
             out.resize(responseLength);
             memcpy(out.data(), requestData, responseLength);
+        } else {
+            m_error = tr("Agent protocol error.");
         }
+    } else {
+        m_error = tr("Agent protocol error.");
     }
 
     UnmapViewOfFile(ptr);
@@ -143,8 +158,13 @@ bool SSHAgent::sendMessage(const QByteArray& in, QByteArray& out) const
 }
 
 
-bool SSHAgent::addIdentity(OpenSSHKey& key, quint32 lifetime, bool confirm) const
+bool SSHAgent::addIdentity(OpenSSHKey& key, quint32 lifetime, bool confirm)
 {
+    if (!isAgentRunning()) {
+        m_error = tr("No agent running, cannot add identity.");
+        return false;
+    }
+
     QByteArray requestData;
     BinaryStream request(&requestData);
 
@@ -161,17 +181,25 @@ bool SSHAgent::addIdentity(OpenSSHKey& key, quint32 lifetime, bool confirm) cons
     }
 
     QByteArray responseData;
-    sendMessage(requestData, responseData);
+    if (!sendMessage(requestData, responseData)) {
+        return false;
+    }
 
     if (responseData.length() < 1 || static_cast<quint8>(responseData[0]) != SSH_AGENT_SUCCESS) {
+        m_error = tr("Agent refused this identity.");
         return false;
     }
 
     return true;
 }
 
-bool SSHAgent::removeIdentity(OpenSSHKey& key) const
+bool SSHAgent::removeIdentity(OpenSSHKey& key)
 {
+    if (!isAgentRunning()) {
+        m_error = tr("No agent running, cannot remove identity.");
+        return false;
+    }
+
     QByteArray requestData;
     BinaryStream request(&requestData);
 
@@ -183,9 +211,12 @@ bool SSHAgent::removeIdentity(OpenSSHKey& key) const
     request.writeString(keyData);
 
     QByteArray responseData;
-    sendMessage(requestData, responseData);
+    if (!sendMessage(requestData, responseData)) {
+        return false;
+    }
 
     if (responseData.length() < 1 || static_cast<quint8>(responseData[0]) != SSH_AGENT_SUCCESS) {
+        m_error = tr("Agent does not have this identity.");
         return false;
     }
 
@@ -210,9 +241,12 @@ void SSHAgent::databaseModeChanged(DatabaseWidget::Mode mode)
     Uuid uuid = widget->database()->uuid();
 
     if (mode == DatabaseWidget::LockedMode && m_keys.contains(uuid.toHex())) {
+
         QSet<OpenSSHKey> keys = m_keys.take(uuid.toHex());
         for (OpenSSHKey key : keys) {
-            removeIdentity(key);
+            if (!removeIdentity(key)) {
+                emit error(m_error);
+            }
         }
     } else if (mode == DatabaseWidget::ViewMode && !m_keys.contains(uuid.toHex())) {
         for (Entry* e : widget->database()->rootGroup()->entriesRecursive()) {
@@ -279,7 +313,9 @@ void SSHAgent::databaseModeChanged(DatabaseWidget::Mode mode)
                     lifetime = settings.lifetimeConstraintDuration();
                 }
 
-                addIdentity(key, lifetime, settings.useConfirmConstraintWhenAdding());
+                if (!addIdentity(key, lifetime, settings.useConfirmConstraintWhenAdding())) {
+                    emit error(m_error);
+                }
             }
         }
     }

src/sshagent/SSHAgent.h

@@ -33,11 +33,15 @@ public:
     static SSHAgent* instance();
     static void init(QObject* parent);
 
+    const QString errorString() const;
     bool isAgentRunning() const;
-    bool addIdentity(OpenSSHKey& key, quint32 lifetime = 0, bool confirm = false) const;
+    bool addIdentity(OpenSSHKey& key, quint32 lifetime = 0, bool confirm = false);
-    bool removeIdentity(OpenSSHKey& key) const;
+    bool removeIdentity(OpenSSHKey& key);
     void removeIdentityAtLock(const OpenSSHKey& key, const Uuid& uuid);
 
+signals:
+    void error(const QString& message);
+
 public slots:
     void databaseModeChanged(DatabaseWidget::Mode mode = DatabaseWidget::LockedMode);
 
@@ -56,7 +60,7 @@ private:
     explicit SSHAgent(QObject* parent = nullptr);
     ~SSHAgent();
 
-    bool sendMessage(const QByteArray& in, QByteArray& out) const;
+    bool sendMessage(const QByteArray& in, QByteArray& out);
 
     static SSHAgent* m_instance;
 
@@ -68,6 +72,7 @@ private:
 #endif
 
     QMap<QString, QSet<OpenSSHKey>> m_keys;
+    QString m_error;
 };
 
 #endif // AGENTCLIENT_H