From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 8 Jan 2013 21:56:31 -0500 From: Nick Bowler To: Paul Gortmaker Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org, Herbert Xu Subject: Re: [v2.6.34-stable 71/77] crypto: ghash - Avoid null pointer dereference if no key is set Message-ID: <20130109025631.GA12832@elliptictech.com> References: <1357688156-25387-1-git-send-email-paul.gortmaker@windriver.com> <1357688156-25387-72-git-send-email-paul.gortmaker@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1357688156-25387-72-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: On 2013-01-08 18:35 -0500, Paul Gortmaker wrote: > From: Nick Bowler > > ------------------- > This is a commit scheduled for the next v2.6.34 longterm release. > http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git > If you see a problem with using this for longterm, please comment. > ------------------- > > commit 7ed47b7d142ec99ad6880bbbec51e9f12b3af74c upstream. > > The ghash_update function passes a pointer to gf128mul_4k_lle which will > be NULL if ghash_setkey is not called or if the most recent call to > ghash_setkey failed to allocate memory. This causes an oops. Fix this > up by returning an error code in the null case. > > This is trivially triggered from unprivileged userspace through the > AF_ALG interface by simply writing to the socket without setting a key. I haven't been following 2.6.34-longterm development, but unless you've also backported the AF_ALG userspace interface from 2.6.38, this sequence can only be triggered by kernel code. So while this patch shouldn't break anything, it isn't really necessary. Cheers, -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)