Date: Fri, 06 May 2011 13:04:47 -0700 (PDT)
Message-Id: <20110506.130447.183054252.davem@davemloft.net>
To: gerrit@erg.abdn.ac.uk
Cc: drosenberg@vsecurity.com, dccp@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, security@kernel.org
Subject: Re: [PATCH] dccp: handle invalid feature options length
From: David Miller <davem@davemloft.net>
In-Reply-To: <20110506195733.GA3527@gerrit.erg.abdn.ac.uk>
References: <1304688438.29544.16.camel@dan>
	<20110506195733.GA3527@gerrit.erg.abdn.ac.uk>
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From: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Date: Fri, 6 May 2011 21:57:33 +0200

> Quoting Dan Rosenberg:
> | A length of zero (after subtracting two for the type and len fields) for
> | the DCCPO_{CHANGE,CONFIRM}_{L,R} options will cause an underflow due to
> | the subtraction.  The subsequent code may read past the end of the
> | options value buffer when parsing.  I'm unsure of what the consequences
> | of this might be, but it's probably not good.
> | 
> Please disregard my earlier message, I erred.
> Dan is right, his patch is correct and definitively valid.
> A length of 0 would be cast to 0xff and then cause buffer overrun.
> 
> | Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
> | Cc: stable@kernel.org
> Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

Great, I'll apply this, thanks!
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