From: Herbert Xu Subject: Re: [PATCH] crypto: ccm - preserve the IV buffer Date: Fri, 3 Nov 2017 21:43:07 +0800 Message-ID: <20171103134307.GB8811@gondor.apana.org.au> References: <20171031144235.22818-1-romain.izard.pro@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "David S . Miller" , Tudor Ambarus , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org To: Romain Izard Return-path: Received: from orcrist.hmeau.com ([104.223.48.154]:37986 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756312AbdKCNne (ORCPT ); Fri, 3 Nov 2017 09:43:34 -0400 Content-Disposition: inline In-Reply-To: <20171031144235.22818-1-romain.izard.pro@gmail.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Tue, Oct 31, 2017 at 03:42:35PM +0100, Romain Izard wrote: > The IV buffer used during CCM operations is used twice, during both the > hashing step and the ciphering step. > > When using a hardware accelerator that updates the contents of the IV > buffer at the end of ciphering operations, the value will be modified. > In the decryption case, the subsequent setup of the hashing algorithm > will interpret the updated IV instead of the original value, which can > lead to out-of-bounds writes. > > Reuse the idata buffer, only used in the hashing step, to preserve the > IV's value during the ciphering step in the decryption case. > > Signed-off-by: Romain Izard Patch applied. Thanks. -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt