Giving root access retroactively

abe+blog@deuxchevaux.org (Axel Beckert) — Wed, 08 Mar 2006 18:59:26 +0100

How often did you start to edit a file from your usual Unix user account and then noticed, that you only can save the file as root? I often did.

Sec wrote a little tool named presto which helps in this situation on FreeBSD. Initially only being a proof of concept tool to show that write access to /dev/kmem is as good as root access, the tool now has a useful purpose: Called from any editor or other tool (e.g. via sudo), it gives that tool super user privileges retroactively. So in vi, you just can type :!sudo presto to save the opened file, even if only root can write to it. (Works only with security level 0 or -1.)

Oh, and btw: Don’t use presto with Emacs. Emacs isn’t an editor for one file…. ;-)

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Giving root access retroactively