Shrinking an outsized KeePassX/KeePass database

There is an error in KeePassX (and there was a similar bug in KeePass, too) that can cause the database file to grow at a very rapid pace (I don't know what triggers this growth). To be precise, the database size doubles every time it is saved even if a very small change is made.

My database reached 256 MB. KeePass running on Windows XP could not open it (because of an Out of memory error) while KeePassX on Ubuntu could open it but it was taking a few minutes. But the main problem anyway was the fact that I couldn't add new entries or make any changes because the file would grow again.

I tried to shrink the file by saving it as a new database or exporting and then importing it, but it didn't work. I also tried to find a solution on the Internet, but I only found an information that there was such a bug and it was fixed in Windows version. So after a few days I downloaded the KeePass sources, spent half a day (it's been a long time since I last saw a C++ code :) first trying to make them compile (I didn't have a libboost_regex-vc80-mt-sgd-1_34_1.lib library file; I installed it with BoostPro Binary Installer for Visual C++ - take a look here and here) and then trying to find a place in the code where the individual entries get loaded. :)

Finally, it turned out that the problem was caused by an attachment which was taking almost all space in the database file (it had a few KB when I attached it some time ago).

So I placed a line responsible for loading the attachment inside a try... catch... block and added a message box.

try
{
pEntry->pszBinaryDesc = _UTF8ToString((UTF8_BYTE *)pData);
}
catch (...)
{
AfxMessageBox((CString)"There was a problem with reading pszBinaryDesc " 
+ (CString)"field of " + pEntry->pszTitle + (CString)" entry.\n"
+ (CString)"This data has been LOST. However, you can now save the "
+ (CString)"database as a new file and its size should be normal again.", 
MB_ICONEXCLAMATION);
}

Thanks to this if there is a broken (outsized) attachment in some entry, an exception is thrown (important: if you try to run KeePass on Linux using WINE, this exception will not be thrown) and KeePass skips loading it and informs the user that such a problem occurred. Be aware that I didn't find a way to restore a broken attachment so some data is lost, but the database can be opened and saved as a new database. The new database has a normal size.

If anyone has a similar problem, let me know - I can e-mail modified sources or a compiled EXE file.

UPDATE:

A tip from an anonymous reader:

I was able to get around the same issue and shrink my keepass database via "File" -> "Export To" -> "KeePass Database" in v1.14. Using "Save As" wouldn't do it, but exporting did the trick!

Shorewall does not start at boot time

I am neither shell scripting nor security guru, but I think that there is an error in the /etc/init.d/shorewall script that installs with the version 3.2.6-2 of Shorewall.

I installed Shorewall using Synaptic today, configured it and tested that I can start it manually. Then I restarted the computer and found out that there are no rules defined in any iptables chain (sudo iptables -L). I used the sudo invoke-rc.d shorewall start command to check what's happening during boot time and I saw the following error:

  Please read about Debian specific customization in
  /usr/share/doc/shorewall/README.Debian.gz.

After a few minutes of checking by trial and error I knew there was a problem with a piece of code right after the # check if shorewall is configured or not comment and after a few more minutes I modified it and the problem was solved. Below is the modified version - the script was looking for a wrong file and checking a non-existent variable.

# check if shorewall is configured or not
if [ -f "/etc/shorewall/shorewall.conf" ]
then
. /etc/shorewall/shorewall.conf
if [ "$STARTUP_ENABLED" != "Yes" ]
then
not_configured
fi
else
not_configured
fi

Changing file permissions (chmod) without SSH/telnet access

If you need to change file permissions (chmod) for more than just a few files and your web hosting provider gives you only FTP access to your account (neither SSH/telnet nor a good web hosting control panel system), you can use the chmod function available in PHP.

You can either write a PHP script that calls chmod for each file that needs its permissions to be changed or use this snippet to call chmod recursively and change permissions for an entire folder tree.

KeePassX looks ugly; making it look good again

If KeePassX (or other Qt application) looks really awful on your machine, the problem is probably the GUI Style chosen for Qt applications.

For quite a long time I couldn't find a way to change it, until I read this howto. I installed the qt4-qtconfig package and used the Qt Configuration tool (run qtconfig) to change the GUI Style to Plastique. You can see the results below.

Before


After

HOWTO: Configure SQL Server 2005 to allow remote connections

I know it doesn't seem a very hard task, but it really took me quite a lot of time to configure a SQL Server 2005 instance running on Windows XP SP2 machine to allow remote connections.

This KB article describes step by step what you have to do to be able to connect remotely to a SQL Server 2005.

In my case, there were two problems:

1. I disabled SQL Server Browser service (which has to be running if you want to use a named instance),
2. I didn't know that in Windows Firewall you can create exceptions for particular applications (and not only ports).

Why can't I decrypt a string I've just encrypted?

If you are using one of .NET CryptoService providers (like DESCryptoServiceProvider or RijndaelManaged), there's a trap that you can easily fall in (I did).

To encrypt data (a string converted previously into a byte array), you create a CryptoStream that reads bytes from this array, transforms them, and then writes encrypted data to a stream.

Then you can use ToArray() method of the stream to obtain encrypted bytes.

And what do you do next?

You run something like:
  Encoding.Unicode.GetString(cipherBytes)

And you have a problem. The encrypted string is encoded in Unicode. That's fine as long as you want to write it into a file or store in a database, but sometimes you want to be able to enter it using the keyboard.

To solve this problem use:
  Convert.ToBase64String(cipherBytes)

This way the encrypted string will be encoded with ASCII characters only.

If you want to know more, read this article.