add chaff to encrypted documents

1 files changed, 115 insertions, 0 deletions

diff --git a/comphelper/source/xml/xmltools.cxx b/comphelper/source/xml/xmltools.cxx
new file mode 100644
index 000000000000..c5a5a724d77a
--- /dev/null
+++ b/comphelper/source/xml/xmltools.cxx
@@ -0,0 +1,115 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * Version: MPL 1.1 / GPLv3+ / LGPLv3+
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Initial Developer of the Original Code is
+ *        Caolán McNamara <caolanm@redhat.com> (Red Hat, Inc.)
+ * Portions created by the Initial Developer are Copyright (C) 2011 the
+ * Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s): Caolán McNamara <caolanm@redhat.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 3 or later (the "GPLv3+"), or
+ * the GNU Lesser General Public License Version 3 or later (the "LGPLv3+"),
+ * in which case the provisions of the GPLv3+ or the LGPLv3+ are applicable
+ * instead of those above.
+ */
+#include <comphelper/xmltools.hxx>
+#include <rtl/random.h>
+#include <boost/static_assert.hpp>
+#include <vector>
+
+using namespace com::sun::star;
+
+namespace
+{
+    //Will be inside an xml comment, so can't use '-' in case '--' appears in
+    //output, etc. Despite what *is* legal in an xml comment, just using the
+    //base-64 subset to avoid pain with simplistic third-party parsers
+    static const sal_uInt8 aChaffEncoder[] =
+    {
+        'A', 'Q', 'g', 'w', 'B', 'R', 'h', 'x',
+        'C', 'S', 'i', 'y', 'D', 'T', 'j', 'z',
+        'E', 'U', 'k', '0', 'F', 'V', 'l', '1',
+        'G', 'W', 'm', '2', 'H', 'X', 'n', '3',
+        'I', 'Y', 'o', '4', 'J', 'Z', 'p', '5',
+        'K', 'a', 'q', '6', 'L', 'b', 'r', '7',
+        'M', 'c', 's', '8', 'N', 'd', 't', '9',
+        'O', 'e', 'u', '+', 'P', 'f', 'v', '/',
+
+        'A', 'Q', 'g', 'w', 'B', 'R', 'h', 'x',
+        'C', 'S', 'i', 'y', 'D', 'T', 'j', 'z',
+        'E', 'U', 'k', '0', 'F', 'V', 'l', '1',
+        'G', 'W', 'm', '2', 'H', 'X', 'n', '3',
+        'I', 'Y', 'o', '4', 'J', 'Z', 'p', '5',
+        'K', 'a', 'q', '6', 'L', 'b', 'r', '7',
+        'M', 'c', 's', '8', 'N', 'd', 't', '9',
+        'O', 'e', 'u', '+', 'P', 'f', 'v', '/',
+
+        'A', 'Q', 'g', 'w', 'B', 'R', 'h', 'x',
+        'C', 'S', 'i', 'y', 'D', 'T', 'j', 'z',
+        'E', 'U', 'k', '0', 'F', 'V', 'l', '1',
+        'G', 'W', 'm', '2', 'H', 'X', 'n', '3',
+        'I', 'Y', 'o', '4', 'J', 'Z', 'p', '5',
+        'K', 'a', 'q', '6', 'L', 'b', 'r', '7',
+        'M', 'c', 's', '8', 'N', 'd', 't', '9',
+        'O', 'e', 'u', '+', 'P', 'f', 'v', '/',
+
+        'A', 'Q', 'g', 'w', 'B', 'R', 'h', 'x',
+        'C', 'S', 'i', 'y', 'D', 'T', 'j', 'z',
+        'E', 'U', 'k', '0', 'F', 'V', 'l', '1',
+        'G', 'W', 'm', '2', 'H', 'X', 'n', '3',
+        'I', 'Y', 'o', '4', 'J', 'Z', 'p', '5',
+        'K', 'a', 'q', '6', 'L', 'b', 'r', '7',
+        'M', 'c', 's', '8', 'N', 'd', 't', '9',
+        'O', 'e', 'u', '+', 'P', 'f', 'v', '/'
+    };
+
+    void encodeChaff(std::vector<sal_uInt8> &rChaff)
+    {
+        BOOST_STATIC_ASSERT(sizeof(aChaffEncoder) == 256);
+
+        for (std::vector<sal_uInt8>::iterator aI = rChaff.begin(), aEnd = rChaff.end();
+            aI != aEnd; ++aI)
+        {
+            *aI = aChaffEncoder[*aI];
+        }
+    }
+}
+
+namespace comphelper
+{
+    namespace xml
+    {
+        rtl::OString makeXMLChaff()
+        {
+            rtlRandomPool pool = rtl_random_createPool();
+
+            sal_Int8 n;
+            rtl_random_getBytes(pool, &n, 1);
+
+            //1024 minus max -127/plus max 128
+            sal_Int32 nLength = 1024+n;
+            std::vector<sal_uInt8> aChaff(nLength);
+            rtl_random_getBytes(pool, &aChaff[0], nLength);
+
+            rtl_random_destroyPool(pool);
+
+            encodeChaff(aChaff);
+
+            return rtl::OString(reinterpret_cast<const sal_Char*>(&aChaff[0]), nLength);
+        }
+    }
+}
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */