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,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 362FEC7618B for ; Thu, 25 Jul 2019 06:12:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0E00621850 for ; Thu, 25 Jul 2019 06:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727264AbfGYGMm (ORCPT ); Thu, 25 Jul 2019 02:12:42 -0400 Received: from mx2.suse.de ([195.135.220.15]:45352 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726001AbfGYGMm (ORCPT ); Thu, 25 Jul 2019 02:12:42 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8351EB090; Thu, 25 Jul 2019 06:12:41 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: Jungyeon Yoon Subject: [PATCH v2 0/5] btrfs: Enhanced runtime defence against fuzzed images Date: Thu, 25 Jul 2019 14:12:17 +0800 Message-Id: <20190725061222.9581-1-wqu@suse.com> X-Mailer: git-send-email 2.22.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Another wave of defence enhancment, including: - Enhanced eb accessors Not really needed for the fuzzed images, as 448de471cd4c ("btrfs: Check the first key and level for cached extent buffer") already fixed half of the reported images. Just add a final layer of safe net. Just to complain here, two experienced btrfs developer have got confused by @start, @len in functions like read_extent_buffer() with logical address. The best example to solve the confusion is to check the read_extent_buffer() call in btree_read_extent_buffer_pages(). I'm not sure why this confusion happens or even get spread. My guess is the extent_buffer::start naming causing the problem. If so, I would definitely rename extent_buffer::start to extent_buffer::bytenr at any cost. Hopes the new commend will address the problem for now. - BUG_ON() hunt in __btrfs_free_extent() Kill BUG_ON()s in __btrfs_free_extent(), replace with error reporting and why it shouldn't happen. Also add comment on what __btrfs_free_extent() is designed to do, with two dump-tree examples for newcomers. - BUG_ON() hunt in __btrfs_inc_extent_ref() Just like __btrfs_free_extent(), but less comment as comment for __btrfs_free_extent() should also work for __btrfs_inc_extent_ref(), and __btrfs_inc_extent_ref() has a better structure than __btrfs_free_extent(). - Defence against unbalanced empty leaf - Defence against bad key order across two tree blocks The last two cases can't be rejected by tree-checker and they are all cross-eb cases. Thankfully we can reuse existing first_key check against unbalanced empty leaf, but needs extra check deep into ctree.c for tree block merging time check. Reported-by: Jungyeon Yoon [ Not to mail bombarding the report, thus only RB tag in cover letter ] Changelog: v2: - Remove duplicated error message in WARN() call. Changed to WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG)) Also move WARN() after btrfs error message. - Fix a comment error in __btrfs_free_extent() It's not adding refs to a tree block, but adding the same refs to an existing tree block ref. It's impossible a btrfs tree owning the same tree block directly twice. - Add comment for eb accessors about @start and @len If anyone could tell me why such confusion between @start @len and logical address is here, I will definitely solve the root cause no matter how many codes need to be modified. - Use bool to replace int where only two values are returned Also rename to follow the bool type. - Remove one unrelated change for the error handler in btrfs_inc_extent_ref() - Add Reviewed-by tag Qu Wenruo (5): btrfs: extent_io: Do extra check for extent buffer read write functions btrfs: extent-tree: Kill BUG_ON() in __btrfs_free_extent() and do better comment btrfs: Detect unbalanced tree with empty leaf before crashing btree operations btrfs: extent-tree: Kill the BUG_ON() in insert_inline_extent_backref() btrfs: ctree: Checking key orders before merged tree blocks fs/btrfs/ctree.c | 68 +++++++++++++++++ fs/btrfs/disk-io.c | 8 ++ fs/btrfs/extent-tree.c | 164 ++++++++++++++++++++++++++++++++++++---- fs/btrfs/extent_io.c | 76 ++++++++++--------- fs/btrfs/tree-checker.c | 6 ++ 5 files changed, 271 insertions(+), 51 deletions(-) -- 2.22.0