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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 1B191C7618B for ; Fri, 26 Jul 2019 08:15:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D44EC21901 for ; Fri, 26 Jul 2019 08:15:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="EKBg3foM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726591AbfGZIP0 (ORCPT ); Fri, 26 Jul 2019 04:15:26 -0400 Received: from esa3.hgst.iphmx.com ([216.71.153.141]:11529 "EHLO esa3.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726203AbfGZIPU (ORCPT ); Fri, 26 Jul 2019 04:15:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1564128920; x=1595664920; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=VkKIzJq+7U8jxmFSMc0E2oXrCb2hdYr8AaDhljLA4QI=; b=EKBg3foMd8yQ/daYSeID3B5YRFrDkUUEOJuD8QPlXU9YZQg8+hGza++e zhVCipO6pICUJIVwDKFyXL12yycATTvITpya3STCDCuX7KveASstHTHlr cbshtH9zT6u0zYzXfPoY5mfM/Zsh/5ickXpSnkkg/LZVZYF1xIs23tgVn rWy0tOKR+NhLBv1k7Hu9obnkzAUNFPnABvW87uojMrYzvy+SxtEaQozQc kE+3S5Ln0u1T6okcS3RhbEohKoiJRArmc/GDFh8KEwwHzKJlb71cRj7lT 7x0+xM36ThfYKi5XuYt0aNqO2bc25Avebod+DqAqWLVFCbeYCFHOmVxMn g==; IronPort-SDR: 10bZR+NoEGPdyWnkEIONXM+kCuJrFXf/2pAp7ehUiNHlUN89U6Cq4NyhrHyzqi6RvkoJL/e7tL bHgVuFesJAZJ5a64+oHkunNXP8dn1yxeVLEjwKfFRaXq1/wO/lk5ALaSViZ0YeQVrxyjmxwWIj hNJquri30lrgmXYQijCy215uTqiU1nlUxNvTzNJom3HydIoNWrANcB+RLPFlgRcp2UulrmhJhE C0omPI6xeXG9kddJ26goAF4FrKG8a9XxAFM1R2LcSa61C8X8Hl0gCHZutUf8qd1LYo3uPfNimc bYk= X-IronPort-AV: E=Sophos;i="5.64,310,1559491200"; d="scan'208";a="118889135" Received: from h199-255-45-14.hgst.com (HELO uls-op-cesaep01.wdc.com) ([199.255.45.14]) by ob1.hgst.iphmx.com with ESMTP; 26 Jul 2019 16:15:20 +0800 IronPort-SDR: 2e+EgDWxq8EqUY7K5svt/E1RcCx+YLE4A2x2UsRzSa2pKObVSIHJ/HJGwsHh2LRUpoowPskMYn PirEtaLefUiOG4v8ummlAl6pNyjJ8VysaiSaNhf4cQqyO2YWQIflc/Rv0+a34DYSc80QJA/H+R glRIspPbSvKEWHvf6PVdqqAnV+BVzpc3bDQMzDcGqGxR6t+1LCz597907yNmVVRgvl9avQRCns ppib+ftPRqY/fkXWE3bXkAlmjctT2swNdJqrruxNrwHa9R3NB5XDE+DC2ByYjdxH2l0xDrzHYj FctLre9cSVLZdWPQrptgF4CT Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep01.wdc.com with ESMTP; 26 Jul 2019 01:13:29 -0700 IronPort-SDR: OCgvOK6qKbgd6PVS6MyE6ZgZlOTQsww/TXASZd1Dr1Xbis51aQwkbscoSoyz0l+rLI/4LAXgnm 0vJdERRVCII/caB2xgalILMEqxyoMIJ93I3iKaaIhcO9Upo3Uuk3JBiciKSjIlsSSl0SNXEjJB rP5JY2w2p5cQXb3H/E/7nn95AR+lgQFFJg/5chVEAAxIPzMktzP7eI2mdKd++DhZVysA4Tz7HH lz0LmGlD57lm9DPRfwYr6X0qEkHNAxcEpqBOtk4e1zwvS6CWDmv9oeb5/G7kg6hU5hDQRZgEy9 qsk= Received: from naota.dhcp.fujisawa.hgst.com ([10.149.53.115]) by uls-op-cesaip02.wdc.com with SMTP; 26 Jul 2019 01:15:19 -0700 Received: (nullmailer pid 12698 invoked by uid 1000); Fri, 26 Jul 2019 08:15:18 -0000 Date: Fri, 26 Jul 2019 17:15:18 +0900 From: Naohiro Aota To: Qu Wenruo Cc: Nikolay Borisov , linux-btrfs@vger.kernel.org, David Sterba Subject: Re: [PATCH] btrfs: fix extent buffer read/write range checks Message-ID: <20190726081518.ilukyrpdsrioiq36@naota.dhcp.fujisawa.hgst.com> References: <20190726052724.12338-1-naohiro.aota@wdc.com> <20190726061300.gvwypjd32elqtkhu@naota.dhcp.fujisawa.hgst.com> <71f0399e-0719-ca8c-cb7b-aba5de5d0c5a@gmx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <71f0399e-0719-ca8c-cb7b-aba5de5d0c5a@gmx.com> User-Agent: NeoMutt/20180716 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Fri, Jul 26, 2019 at 02:36:10PM +0800, Qu Wenruo wrote: > > >On 2019/7/26 下午2:13, Naohiro Aota wrote: >> On Fri, Jul 26, 2019 at 08:38:27AM +0300, Nikolay Borisov wrote: >>> >>> >>> On 26.07.19 г. 8:27 ч., Naohiro Aota wrote: >>>> Several functions to read/write an extent buffer check if specified >>>> offset >>>> range resides in the size of the extent buffer. However, those checks >>>> have >>>> two problems: >>>> >>>> (1) they don't catch "start == eb->len" case. >>>> (2) it checks offset in extent buffer against logical address using >>>>     eb->start. >>>> >>>> Generally, eb->start is much larger than the offset, so the second >>>> WARN_ON >>>> was almost useless. >>>> >>>> Fix these problems in read_extent_buffer_to_user(), >>>> {memcmp,write,memzero}_extent_buffer(). >>>> >>>> Signed-off-by: Naohiro Aota >>> >>> Qu already sent similar patch: >>> >>> [PATCH v2 1/5] btrfs: extent_io: Do extra check for extent buffer read >>> write functions >>> >>> >>> He centralised the checking code, your >= fixes though should be merged >>> there. >> >> Oops, I missed that series. Thank you for pointing out. Then, this >> should be merged into Qu's version. >> >> Qu, could you pick the change from "start > eb->len" to "start >= eb->len"? > > start >= eb->len is not always invalid. > > start == eb->len while len == 0 is still valid. Correct. But then, we can even say "start > eb->len" is valid if len == 0? > Or should we also warn such bad practice? Maybe... Or how about let the callers bailing out by e.g. "if (!len) return 1;" in the check function? Regards, Naohiro