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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 21879C48BDB for ; Sun, 7 Jul 2019 19:46:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 022FF20663 for ; Sun, 7 Jul 2019 19:46:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728719AbfGGTqZ (ORCPT ); Sun, 7 Jul 2019 15:46:25 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57018 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727503AbfGGTiE (ORCPT ); Sun, 7 Jul 2019 15:38:04 -0400 Received: from 94.197.121.43.threembb.co.uk ([94.197.121.43] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hkCz2-0006eG-JV; Sun, 07 Jul 2019 20:38:00 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hkCz1-0005YC-2a; Sun, 07 Jul 2019 20:37:59 +0100 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 , "Herbert Xu" , "David Howells" , "Eric Biggers" Date: Sun, 07 Jul 2019 17:54:17 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 024/129] crypto: pcbc - remove bogus memcpy()s with src == dest In-Reply-To: X-SA-Exim-Connect-IP: 94.197.121.43 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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.70-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit 251b7aea34ba3c4d4fdfa9447695642eb8b8b098 upstream. The memcpy()s in the PCBC implementation use walk->iv as both the source and destination, which has undefined behavior. These memcpy()'s are actually unneeded, because walk->iv is already used to hold the previous plaintext block XOR'd with the previous ciphertext block. Thus, walk->iv is already updated to its final value. So remove the broken and unnecessary memcpy()s. Fixes: 91652be5d1b9 ("[CRYPTO] pcbc: Add Propagated CBC template") Cc: David Howells Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- crypto/pcbc.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) --- a/crypto/pcbc.c +++ b/crypto/pcbc.c @@ -52,7 +52,7 @@ static int crypto_pcbc_encrypt_segment(s unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; u8 *dst = walk->dst.virt.addr; - u8 *iv = walk->iv; + u8 * const iv = walk->iv; do { crypto_xor(iv, src, bsize); @@ -76,7 +76,7 @@ static int crypto_pcbc_encrypt_inplace(s int bsize = crypto_cipher_blocksize(tfm); unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; - u8 *iv = walk->iv; + u8 * const iv = walk->iv; u8 tmpbuf[bsize]; do { @@ -89,8 +89,6 @@ static int crypto_pcbc_encrypt_inplace(s src += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } @@ -130,7 +128,7 @@ static int crypto_pcbc_decrypt_segment(s unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; u8 *dst = walk->dst.virt.addr; - u8 *iv = walk->iv; + u8 * const iv = walk->iv; do { fn(crypto_cipher_tfm(tfm), dst, src); @@ -142,8 +140,6 @@ static int crypto_pcbc_decrypt_segment(s dst += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } @@ -156,7 +152,7 @@ static int crypto_pcbc_decrypt_inplace(s int bsize = crypto_cipher_blocksize(tfm); unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; - u8 *iv = walk->iv; + u8 * const iv = walk->iv; u8 tmpbuf[bsize]; do { @@ -169,8 +165,6 @@ static int crypto_pcbc_decrypt_inplace(s src += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; }