VSFTPD chroot broken functionality in 2.3.5

Debian 7 was released, and like all good sysadmin’s we updated our servers to the newer OS version.
Unfortunately there have been a few minor issues where functionality has changed.

One of those relates to FTP.

We generally use VSFTP as its relatively secure, and has chroot functionality out of the box (i.e. users can only see their own folders).
Today a user complained that they couldn’t login, and on checking we saw this little error:

500 OOPS: vsftpd: refusing to run with writable root inside chroot ()

A quick google showed that 2.3.5 breaks backward compatibility somewhat by changing functionality, oops!
This was done for safety reasons, but is a bit of a questionable change to functionality when it breaks things.

The suggestions on the internet were to add this line:

allow_writeable_chroot=YES

Which didn’t work – VSFTP wouldn’t restart, as it didn’t recognize it. What to do?

Well, the quick solution is to use Debian unstable, as that uses a newer version of VSFTP 3.x which does recognize that line.

So:

(assuming you have the testing repo’s in apt.sources)

apt-get install -t testing vsftpd
echo allow_writeable_chroot=YES >> /etc/vsftpd.conf
/etc/init.d/vsftpd restart