Add repair functionality to strip invalid XML chars.

Refs #392

src/format/KeePass2Reader.cpp

@@ -43,7 +43,7 @@ KeePass2Reader::KeePass2Reader()
 {
 }
 
-Database* KeePass2Reader::readDatabase(QIODevice* device, const CompositeKey& key)
+Database* KeePass2Reader::readDatabase(QIODevice* device, const CompositeKey& key, bool keepDatabase)
 {
     QScopedPointer<Database> db(new Database());
     m_db = db.data();
@@ -178,7 +178,12 @@ Database* KeePass2Reader::readDatabase(QIODevice* device, const CompositeKey& ke
 
     if (xmlReader.hasError()) {
         raiseError(xmlReader.errorString());
-        return Q_NULLPTR;
+        if (keepDatabase) {
+            return db.take();
+        }
+        else {
+            return Q_NULLPTR;
+        }
     }
 
     Q_ASSERT(version < 0x00030001 || !xmlReader.headerHash().isEmpty());
@@ -232,6 +237,11 @@ QByteArray KeePass2Reader::xmlData()
     return m_xmlData;
 }
 
+QByteArray KeePass2Reader::streamKey()
+{
+    return m_protectedStreamKey;
+}
+
 void KeePass2Reader::raiseError(const QString& errorMessage)
 {
     m_error = true;

src/format/KeePass2Reader.h

@@ -31,12 +31,13 @@ class KeePass2Reader
 
 public:
     KeePass2Reader();
-    Database* readDatabase(QIODevice* device, const CompositeKey& key);
+    Database* readDatabase(QIODevice* device, const CompositeKey& key, bool keepDatabase = false);
     Database* readDatabase(const QString& filename, const CompositeKey& key);
     bool hasError();
     QString errorString();
     void setSaveXml(bool save);
     QByteArray xmlData();
+    QByteArray streamKey();
 
 private:
     void raiseError(const QString& errorMessage);

src/format/KeePass2Repair.cpp

@@ -0,0 +1,107 @@
+/*
+ *  Copyright (C) 2016 Felix Geyer <debfx@fobos.de>
+ *
+ *  This program 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 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "KeePass2Repair.h"
+
+#include <QBuffer>
+#include <QRegExp>
+
+#include "format/KeePass2RandomStream.h"
+#include "format/KeePass2Reader.h"
+#include "format/KeePass2XmlReader.h"
+
+KeePass2Repair::KeePass2Repair()
+    : m_db(Q_NULLPTR)
+{
+}
+
+KeePass2Repair::RepairResult KeePass2Repair::repairDatabase(QIODevice* device, const CompositeKey& key)
+{
+    m_db = Q_NULLPTR;
+    m_errorStr.clear();
+
+    KeePass2Reader reader;
+    reader.setSaveXml(true);
+
+    Database* db = reader.readDatabase(device, key, true);
+    if (!reader.hasError()) {
+        delete db;
+        return NothingTodo;
+    }
+
+    QByteArray xmlData = reader.xmlData();
+    if (!db || xmlData.isEmpty()) {
+        delete db;
+        m_errorStr = reader.errorString();
+        return UnableToOpen;
+    }
+
+    bool repairAction = false;
+
+    QString xmlStart = QString::fromLatin1(xmlData.constData(), qMin(100, xmlData.size()));
+    QRegExp encodingRegExp("encoding=\"([^\"]+)\"", Qt::CaseInsensitive, QRegExp::RegExp2);
+    if (encodingRegExp.indexIn(xmlStart) != -1) {
+        if (encodingRegExp.cap(1).compare("utf-8", Qt::CaseInsensitive) != 0
+                && encodingRegExp.cap(1).compare("utf8", Qt::CaseInsensitive) != 0)
+        {
+            // database is not utf-8 encoded, we don't support repairing that
+            delete db;
+            return RepairFailed;
+        }
+    }
+
+    // try to fix broken databases because of bug #392
+    for (int i = (xmlData.size() - 1); i >= 0; i--) {
+        char ch = xmlData.at(i);
+        if (ch < 0x20 && ch != 0x09 && ch != 0x0A && ch != 0x0D) {
+            xmlData.remove(i, 1);
+            repairAction = true;
+        }
+    }
+
+    if (!repairAction) {
+        // we were unable to find the problem
+        delete db;
+        return RepairFailed;
+    }
+
+    KeePass2RandomStream randomStream;
+    randomStream.init(reader.streamKey());
+    KeePass2XmlReader xmlReader;
+    QBuffer buffer(&xmlData);
+    buffer.open(QIODevice::ReadOnly);
+    xmlReader.readDatabase(&buffer, db, &randomStream);
+
+    if (xmlReader.hasError()) {
+        delete db;
+        return RepairFailed;
+    }
+    else {
+        m_db = db;
+        return RepairSuccess;
+    }
+}
+
+Database* KeePass2Repair::database() const
+{
+    return m_db;
+}
+
+QString KeePass2Repair::errorString() const
+{
+    return m_errorStr;
+}

src/format/KeePass2Repair.h

@@ -0,0 +1,50 @@
+/*
+ *  Copyright (C) 2016 Felix Geyer <debfx@fobos.de>
+ *
+ *  This program 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 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef KEEPASSX_KEEPASS2REPAIR_H
+#define KEEPASSX_KEEPASS2REPAIR_H
+
+#include <QCoreApplication>
+#include <QIODevice>
+
+#include "core/Database.h"
+#include "keys/CompositeKey.h"
+
+class KeePass2Repair
+{
+    Q_DECLARE_TR_FUNCTIONS(KeePass2Repair)
+
+public:
+    enum RepairResult
+    {
+        NothingTodo,
+        UnableToOpen,
+        RepairSuccess,
+        RepairFailed
+    };
+
+    KeePass2Repair();
+    RepairResult repairDatabase(QIODevice* device, const CompositeKey& key);
+    Database* database() const;
+    QString errorString() const;
+
+private:
+    Database* m_db;
+    QString m_errorStr;
+};
+
+#endif // KEEPASSX_KEEPASS2REPAIR_H