linux-kernel - Re: ls -l /proc/1/exe -> Permission denied

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Message-ID: <OF2729CE69.3EF22126-ONC1257D1B.0069427B-C1257D1B.0069CA17@transmode.se>
Date:	Sun, 20 Jul 2014 21:15:29 +0200
From:	Joakim Tjernlund <joakim.tjernlund@...nsmode.se>
To:	Richard Weinberger <richard@....at>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Andreas Schwab <schwab@...ux-m68k.org>
Subject: Re: ls -l /proc/1/exe -> Permission denied

Richard Weinberger <richard@....at> wrote on 2014/07/20 14:05:41:
> 
> Am 20.07.2014 13:51, schrieb Andreas Schwab:
> > Richard Weinberger <richard.weinberger@...il.com> writes:
> >> Do you have an example?
> > 
> > proc symlinks are special because they actually resolve to the inode.
> 
> Ah. If an attacker manages the kernel to follow the symlink he could
> indirectly access that file.
> Thanks for pointing this out!

That is a big if, I read this as you don't trust the kernels impl.
of proc sym links so paper over this with denying all other to read 
trivial
data such as the exe sym link.

 Jocke 
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