From patchwork Fri Oct 6 01:41:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Herbert Xu X-Patchwork-Id: 730677 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40848E92FD6 for ; Fri, 6 Oct 2023 01:42:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229657AbjJFBmA (ORCPT ); Thu, 5 Oct 2023 21:42:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229666AbjJFBl6 (ORCPT ); Thu, 5 Oct 2023 21:41:58 -0400 Received: from abb.hmeau.com (abb.hmeau.com [144.6.53.87]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3785BE7; Thu, 5 Oct 2023 18:41:57 -0700 (PDT) Received: from loth.rohan.me.apana.org.au ([192.168.167.2]) by formenos.hmeau.com with smtp (Exim 4.94.2 #2 (Debian)) id 1qoZqh-0043of-2s; Fri, 06 Oct 2023 09:41:52 +0800 Received: by loth.rohan.me.apana.org.au (sSMTP sendmail emulation); Fri, 06 Oct 2023 09:41:55 +0800 Date: Fri, 6 Oct 2023 09:41:55 +0800 From: Herbert Xu To: Bagas Sanjaya , Linux Crypto Mailing List Cc: Tatu =?iso-8859-1?q?Heikkil=E4?= , Linux Kernel Mailing List , Linux Device Mapper , Mike Snitzer , Alasdair Kergon , Linux Regressions Subject: [PATCH] dm crypt: Fix reqsize in crypt_iv_eboiv_gen Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Fri, Oct 06, 2023 at 08:04:18AM +0700, Bagas Sanjaya wrote: > > > Git bisect lead me to: > > # first bad commit: [e3023094dffb41540330fb0c74cd3a019cd525c2] dm crypt: > > Avoid using MAX_CIPHER_BLOCKSIZE > > > > If I git revert e3023094dffb41540330fb0c74cd3a019cd525c2 on current Linus' > > git master, the issue goes away. So I'm personally not all that affected > > anymore (if I'm ready to compile my kernels from now on), and I understand > > that you have no clear way to reproduce this as it seems strongly bound to > > hardware, but seems like this could point to a potentially serious security > > issue since it involves both crypto and undefined behaviour. Thanks for the report. Sorry this is indeed my fault. The allocated buffer is too small as it's missing the size for the request object itself. Mike, would you be OK with me picking this fix up and pushing it to Linus? Cheers, ---8<--- A skcipher_request object is made up of struct skcipher_request followed by a variable-sized trailer. The allocation of the skcipher_request and IV in crypt_iv_eboiv_gen is missing the memory for struct skcipher_request. Fix it by adding it to reqsize. Fixes: e3023094dffb ("dm crypt: Avoid using MAX_CIPHER_BLOCKSIZE") Reported-by: Tatu Heikkil� Signed-off-by: Herbert Xu diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index f2662c21a6df..5315fd261c23 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -753,7 +753,8 @@ static int crypt_iv_eboiv_gen(struct crypt_config *cc, u8 *iv, int err; u8 *buf; - reqsize = ALIGN(crypto_skcipher_reqsize(tfm), __alignof__(__le64)); + reqsize = sizeof(*req) + crypto_skcipher_reqsize(tfm); + reqsize = ALIGN(reqsize, __alignof__(__le64)); req = kmalloc(reqsize + cc->iv_size, GFP_NOIO); if (!req)