Date: Mon, 27 Sep 2004 14:03:53 -0700
From: Chris Wright <chrisw@osdl.org>
To: Alan Cox <alan@redhat.com>
Cc: linux-kernel@vger.kernel.org, akpm@osdl.org, torvalds@osdl.org
Subject: Re: Patch for comment: setuid core dumps
Message-ID: <20040927140353.Z1973@build.pdx.osdl.net>
References: <20040927202616.GA22228@devserv.devel.redhat.com>
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In-Reply-To: <20040927202616.GA22228@devserv.devel.redhat.com>; from alan@redhat.com on Mon, Sep 27, 2004 at 04:26:16PM -0400
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* Alan Cox (alan@redhat.com) wrote:
>  
> +suid_dumpable:
> +
> +This value can be used to query and set the core dump mode for setuid
> +or otherwise protected/tainted binaries. The modes are
> +
> +0 - (default) - traditional behaviour. Any process which has changed
> +	privilege levels or is execute only will not be dumped
> +1 - (debug) - all processes dump core when possible. The core dump is
> +	owned by the current user and no security is applied. This is
> +	intended for system debugging situations only.

This looks alright, since it keeps 0 and 1 with same meaning (for any
user of prctl).

> +2 - (suidsafe) - any binary which normally not be dumped is dumped
> +	readable by root only. This allows the end user to remove
> +	such a dump but not access it directly. For security reasons
> +	core dumps in this mode will not overwrite one another or 
> +	other files. This mode is appropriate when adminstrators are
> +	attempting to debug problems in a normal environment.
> +

But, in general, did you double check how this plays with /proc
(task_dumpable) and ptrace_attach type stuff?  That seems sketchy.

thanks,
-chris
-- 
Linux Security Modules     http://lsm.immunix.org     http://lsm.bkbits.net
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