From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E37EBC33CA1 for ; Wed, 8 Jan 2020 19:49:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BCAD120720 for ; Wed, 8 Jan 2020 19:49:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729544AbgAHTtk (ORCPT ); Wed, 8 Jan 2020 14:49:40 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43452 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730405AbgAHTqB (ORCPT ); Wed, 8 Jan 2020 14:46:01 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1ipHHB-0006nm-Eq; Wed, 08 Jan 2020 19:45:57 +0000 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1ipHHB-007dkp-1Q; Wed, 08 Jan 2020 19:45:57 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , linux-crypto@vger.kernel.org, "Eric Biggers" Date: Wed, 08 Jan 2020 19:43:03 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 05/63] crypto: cts - fix crash on short inputs In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org 3.16.81-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers In the CTS template, when the input length is <= one block cipher block (e.g. <= 16 bytes for AES) pass the correct length to the underlying CBC transform rather than one block. This matches the upstream behavior and makes the encryption/decryption operation correctly return -EINVAL when 1 <= nbytes < bsize or succeed when nbytes == 0, rather than crashing. This was fixed upstream incidentally by a large refactoring, commit 0605c41cc53c ("crypto: cts - Convert to skcipher"). But syzkaller easily trips over this when running on older kernels, as it's easily reachable via AF_ALG. Therefore, this patch makes the minimal fix for older kernels. Cc: linux-crypto@vger.kernel.org Fixes: 76cb9521795a ("[CRYPTO] cts: Add CTS mode required for Kerberos AES support") Signed-off-by: Eric Biggers Signed-off-by: Ben Hutchings --- crypto/cts.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/crypto/cts.c +++ b/crypto/cts.c @@ -137,8 +137,8 @@ static int crypto_cts_encrypt(struct blk lcldesc.info = desc->info; lcldesc.flags = desc->flags; - if (tot_blocks == 1) { - err = crypto_blkcipher_encrypt_iv(&lcldesc, dst, src, bsize); + if (tot_blocks <= 1) { + err = crypto_blkcipher_encrypt_iv(&lcldesc, dst, src, nbytes); } else if (nbytes <= bsize * 2) { err = cts_cbc_encrypt(ctx, desc, dst, src, 0, nbytes); } else { @@ -232,8 +232,8 @@ static int crypto_cts_decrypt(struct blk lcldesc.info = desc->info; lcldesc.flags = desc->flags; - if (tot_blocks == 1) { - err = crypto_blkcipher_decrypt_iv(&lcldesc, dst, src, bsize); + if (tot_blocks <= 1) { + err = crypto_blkcipher_decrypt_iv(&lcldesc, dst, src, nbytes); } else if (nbytes <= bsize * 2) { err = cts_cbc_decrypt(ctx, desc, dst, src, 0, nbytes); } else {