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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 AF74CC28CF6 for ; Fri, 3 Aug 2018 13:49:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7403321763 for ; Fri, 3 Aug 2018 13:49:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7403321763 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732222AbeHCPqA (ORCPT ); Fri, 3 Aug 2018 11:46:00 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:59018 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729985AbeHCPqA (ORCPT ); Fri, 3 Aug 2018 11:46:00 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CC08F401DE61; Fri, 3 Aug 2018 13:49:33 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-78.rdu2.redhat.com [10.10.120.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id C1DA21D080; Fri, 3 Aug 2018 13:49:30 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20180722110519.23917-1-tomasbortoli@gmail.com> References: <20180722110519.23917-1-tomasbortoli@gmail.com> To: Tomas Bortoli Cc: dhowells@redhat.com, linux-cachefs@redhat.com, linux-kernel@vger.kernel.org, syzkaller@googlegroups.com Subject: Re: [PATCH] fscache: fscache_set_key() - align alloc and usage MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <17156.1533304170.1@warthog.procyon.org.uk> Date: Fri, 03 Aug 2018 14:49:30 +0100 Message-ID: <17157.1533304170@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Fri, 03 Aug 2018 13:49:33 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Fri, 03 Aug 2018 13:49:33 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'dhowells@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tomas Bortoli wrote: > The fscache_set_key() function allocates the buf pointer if index_key_len > > sizeof(cookie->inline_key). In such cases the allocated space might not be > aligned with the pointer type. This may result in an out-of-bound in the > for-loop later in the same function, as the counter is rounded up. Yeah, it's good idea anyway since I should tell the allocator everything that I expect to use - though kmalloc() will effectively rounds up the size to a multiple of 8 anyway (ie. the smallest allocation granule is 8 bytes). David