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_PASS,URIBL_BLOCKED autolearn=unavailable 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 D69E6C43381 for ; Fri, 29 Mar 2019 00:16:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A25D12075E for ; Fri, 29 Mar 2019 00:16:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728845AbfC2AQm (ORCPT ); Thu, 28 Mar 2019 20:16:42 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:59274 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728717AbfC2AQm (ORCPT ); Thu, 28 Mar 2019 20:16:42 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 4F82314D68F8F; Thu, 28 Mar 2019 17:16:41 -0700 (PDT) Date: Thu, 28 Mar 2019 17:16:40 -0700 (PDT) Message-Id: <20190328.171640.1161931383487396254.davem@davemloft.net> To: andrea.righi@canonical.com Cc: pshelar@ovn.org, netdev@vger.kernel.org, dev@openvswitch.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] openvswitch: fix flow actions reallocation From: David Miller In-Reply-To: <20190328063600.GC16096@xps-13> References: <20190328063600.GC16096@xps-13> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 28 Mar 2019 17:16:41 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Andrea Righi Date: Thu, 28 Mar 2019 07:36:00 +0100 > The flow action buffer can be resized if it's not big enough to contain > all the requested flow actions. However, this resize doesn't take into > account the new requested size, the buffer is only increased by a factor > of 2x. This might be not enough to contain the new data, causing a > buffer overflow, for example: > > [ 42.044472] ============================================================================= > [ 42.045608] BUG kmalloc-96 (Not tainted): Redzone overwritten > [ 42.046415] ----------------------------------------------------------------------------- > > [ 42.047715] Disabling lock debugging due to kernel taint > [ 42.047716] INFO: 0x8bf2c4a5-0x720c0928. First byte 0x0 instead of 0xcc > [ 42.048677] INFO: Slab 0xbc6d2040 objects=29 used=18 fp=0xdc07dec4 flags=0x2808101 > [ 42.049743] INFO: Object 0xd53a3464 @offset=2528 fp=0xccdcdebb > > [ 42.050747] Redzone 76f1b237: cc cc cc cc cc cc cc cc ........ > [ 42.051839] Object d53a3464: 6b 6b 6b 6b 6b 6b 6b 6b 0c 00 00 00 6c 00 00 00 kkkkkkkk....l... > [ 42.053015] Object f49a30cc: 6c 00 0c 00 00 00 00 00 00 00 00 03 78 a3 15 f6 l...........x... > [ 42.054203] Object acfe4220: 20 00 02 00 ff ff ff ff 00 00 00 00 00 00 00 00 ............... > [ 42.055370] Object 21024e91: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > [ 42.056541] Object 070e04c3: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > [ 42.057797] Object 948a777a: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > [ 42.059061] Redzone 8bf2c4a5: 00 00 00 00 .... > [ 42.060189] Padding a681b46e: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ > > Fix by making sure the new buffer is properly resized to contain all the > requested data. > > BugLink: https://bugs.launchpad.net/bugs/1813244 > Signed-off-by: Andrea Righi Applied and queued up for -stable. Althought next time I want to see a proper Fixes: tag.