Re: [ANNOUNCE] DigSig 0.2: kernel module for digital signature verification for binaries

[Valdis . Kletnieks]

On Wed, 01 Oct 2003 12:26:31 +0200, Pavel Machek said:

> > Instead of writing a long detailed explication, I rather give you an 
> > example of how you can use it.
> 
> Can you also add example *why* one would want to use it?
> 
> AFAICS if I want to exec something, I can avoid exec() syscall and do
> mmaps by hand...

The idea isn't to stop you from calling exec*().

The idea is to ensure that if you do execve("/usr/bin/foobar",...) that the
foobar binary hasn't been tampered with and you're not about to launch a binary
differing from what you expected.   Note that on a properly administered
system, this is a *high* level of paranoia, as the file permissions should have
prevented writing to the binary in the first place.  It's also a maintenance
nightmare waiting to happen, as you get to re-sign all the binaries every time
you install a patch, and it won't help prevent trojaned shared libraries...

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