Message-Id: <200509222003.j8MK3i8E010365@turing-police.cc.vt.edu>
To: breno@kalangolinux.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: security patch 
In-Reply-To: Your message of "Thu, 22 Sep 2005 19:44:33 -0000."
             <20050922194433.13200.qmail@webmail2.locasite.com.br> 
From: Valdis.Kletnieks@vt.edu
References: <20050922194433.13200.qmail@webmail2.locasite.com.br>
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On Thu, 22 Sep 2005 19:44:33 -0000, breno@kalangolinux.org said:

> I'm doing a new feature for linux kernel 2.6 to protect against all kinds of buffer
> overflow. It works with new sys_control() system call controling if a process can or can't
> call a system call ie. sys_execve();

This has been done before. ;)

Also, note *VERY* carefully that this does *NOT* protect against buffer overflow
the way ExecShield and PAX and similar do - this merely tries to mitigate the
damage.

Note that you probably don't *DARE* remove open()/read()/write()/close() from
the "permitted syscall" list - and an attacker can have plenty of fun just with
those 4 syscalls.

(That's also why SELinux was designed to give better granularity to syscalls - it
can restrict a program to "write only to files it *should* be able to write").

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