Leopard & Samba & Plaintext Password

So, this one is so weird that I *have* to blog about it.
A number of my colleagues have upgrades their MacBooks to Leopard and then discovered that they can no longer mount their home directories via our corporate Samba systems. Now, the first thing I should mention is that our Samba servers use plaintext passwords (the reason for this is too long to explain here) so the first step is to enable plaintext password support in Leopard.
To do this, you create a /etc/nsmb.conf file using the following command via Terminal:-

sudo vi /etc/nsmb.conf

and you enter the following two lines:-

[default]
minauth=none

Save the file and reboot your machine. When you get back to the Finder, under the "Go" menu select "Connect to Server", and enter the server address URL, usually in the format

smb://<servername>/<loginID>

You should then get a prompt asking for a name and password.
Here's the magic part.
If you have a password with a percent symbol ('%') the login will fail. What you need to do is to change your password so that it doesn't have the '%' symbol and it should all work.
WHY???
My suspicion is that Leopard is constructing a mount URL using the information provided from the login dialog box. The full format of the URL is:

smb://<userID>:<password>@<servername>/<sharename

Since this is a URL, Leopard is parsing the whole string looking for escape characters which start with (you guessed it!) a percent symbol. The format of the escape sequence is %hh where hh is a two digit hexademical value. For example, a space character is ASCII 32 decimal or 20 hexadecimal, so the escape sequence for a space would be %20.
If your password has a percent symbol, the next two characters are interpreted as a hexadecimal value. If it happens to be a valid hex value, the all three characters (the % and the next two) are replaced with one character, which changes the password and the login will fail.
If the two characters are not valid hex values, then the nameauth daemon will crash with a "Bad Number" error (you can see this in the Console) and the mount dialog will spin forever.
So far, I've only been able to prove this with one machine, but I'd be interested to hear if anyone else has similar experiences.
Why this breaks in Leopard but works perfectly well in Tiger is beyond me!

Posted at 12:05AM Jan 30, 2008 by samktan in IT  |  Comments[4]