Subject: Re: [SECURITY] CAN info leak/minor heap overflow

From: Dan Rosenberg <[email-masked]>
Date: Tue, 02 Nov 2010 15:53:25 -0400

> Why is this bad? Can the addresses of CAN-BCM sock structs be used for
> anything from userspace?
> 
> For me they are just intented to be unique numbers ...
> 

This is a bad idea because it makes exploiting other kernel
vulnerabilities easier.  Exposing the address of an object in a slab
cache, especially an object that unprivileged users have some level of
control of, is just an invitation to use that structure when writing
exploits, for heap overflows or otherwise.

-Dan

> > Secondly,
> > on 64-bit platforms, up to 17 bytes may be copied into the buffer.
> 
> Hm - that's indeed not wanted. Will send a patch at least for this issue.
> 
> > Fortunately, structure padding will most likely prevent this from being
> > a problem, except for the trailing NULL byte, which may overwrite the
> > first byte of the next heap object.  Please name your procfile in a way
> > that doesn't leak information and fits into the desired name buffer.
> > 
> > -Dan
> > 
> 
> Regards,
> Oliver