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[2620:137:e000::1:20]) by mx.google.com with ESMTP id qk18-20020a1709077f9200b0078d9c0e896bsi26402550ejc.525.2022.10.24.05.49.41; Mon, 24 Oct 2022 05:50:06 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=jIEbhME1; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231460AbiJXMrv (ORCPT + 99 others); Mon, 24 Oct 2022 08:47:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234210AbiJXMmV (ORCPT ); Mon, 24 Oct 2022 08:42:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4849F7E80B; Mon, 24 Oct 2022 05:08:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B629861281; Mon, 24 Oct 2022 11:42:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8B26C43470; Mon, 24 Oct 2022 11:42:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666611726; bh=iy6+dzbMrtUn8z3Bzy2JPrniPwMyWDR81wptzzfv+ZE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jIEbhME1sh8Uk+j2wwWZ2a0JdV2CUFc5rGNxo/KtluAvQzJ7Gk0lF52jcfkq8l3+/ d3K+7ZAZ+sPuZ3Hn5pqBKVamVUKuyjMKt1SS8eU2xEeQitW0FF18wo2wt7TIIT7PMr cWoyk5W03HlvBnd0ssitJegUzSRoDOex4OeeyBws= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhihao Cheng , Jan Kara Subject: [PATCH 4.9 048/159] quota: Check next/prev free block number after reading from quota file Date: Mon, 24 Oct 2022 13:30:02 +0200 Message-Id: <20221024112951.159251294@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112949.358278806@linuxfoundation.org> References: <20221024112949.358278806@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1747573335881690246?= X-GMAIL-MSGID: =?utf-8?q?1747573335881690246?= From: Zhihao Cheng commit 6c8ea8b8cd4722efd419f91ca46a2dc81b7d89a3 upstream. Following process: Init: v2_read_file_info: <3> dqi_free_blk 0 dqi_free_entry 5 dqi_blks 6 Step 1. chown bin f_a -> dquot_acquire -> v2_write_dquot: qtree_write_dquot do_insert_tree find_free_dqentry get_free_dqblk write_blk(info->dqi_blocks) // info->dqi_blocks = 6, failure. The content in physical block (corresponding to blk 6) is random. Step 2. chown root f_a -> dquot_transfer -> dqput_all -> dqput -> ext4_release_dquot -> v2_release_dquot -> qtree_delete_dquot: dquot_release remove_tree free_dqentry put_free_dqblk(6) info->dqi_free_blk = blk // info->dqi_free_blk = 6 Step 3. drop cache (buffer head for block 6 is released) Step 4. chown bin f_b -> dquot_acquire -> commit_dqblk -> v2_write_dquot: qtree_write_dquot do_insert_tree find_free_dqentry get_free_dqblk dh = (struct qt_disk_dqdbheader *)buf blk = info->dqi_free_blk // 6 ret = read_blk(info, blk, buf) // The content of buf is random info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free) // random blk Step 5. chown bin f_c -> notify_change -> ext4_setattr -> dquot_transfer: dquot = dqget -> acquire_dquot -> ext4_acquire_dquot -> dquot_acquire -> commit_dqblk -> v2_write_dquot -> dq_insert_tree: do_insert_tree find_free_dqentry get_free_dqblk blk = info->dqi_free_blk // If blk < 0 and blk is not an error code, it will be returned as dquot transfer_to[USRQUOTA] = dquot // A random negative value __dquot_transfer(transfer_to) dquot_add_inodes(transfer_to[cnt]) spin_lock(&dquot->dq_dqb_lock) // page fault , which will lead to kernel page fault: Quota error (device sda): qtree_write_dquot: Error -8000 occurred while creating quota BUG: unable to handle page fault for address: ffffffffffffe120 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page Oops: 0002 [#1] PREEMPT SMP CPU: 0 PID: 5974 Comm: chown Not tainted 6.0.0-rc1-00004 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:_raw_spin_lock+0x3a/0x90 Call Trace: dquot_add_inodes+0x28/0x270 __dquot_transfer+0x377/0x840 dquot_transfer+0xde/0x540 ext4_setattr+0x405/0x14d0 notify_change+0x68e/0x9f0 chown_common+0x300/0x430 __x64_sys_fchownat+0x29/0x40 In order to avoid accessing invalid quota memory address, this patch adds block number checking of next/prev free block read from quota file. Fetch a reproducer in [Link]. Link: https://bugzilla.kernel.org/show_bug.cgi?id=216372 Fixes: 1da177e4c3f4152 ("Linux-2.6.12-rc2") CC: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220923134555.2623931-2-chengzhihao1@huawei.com Signed-off-by: Zhihao Cheng Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/quota/quota_tree.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) --- a/fs/quota/quota_tree.c +++ b/fs/quota/quota_tree.c @@ -79,6 +79,35 @@ static ssize_t write_blk(struct qtree_me return ret; } +static inline int do_check_range(struct super_block *sb, const char *val_name, + uint val, uint min_val, uint max_val) +{ + if (val < min_val || val > max_val) { + quota_error(sb, "Getting %s %u out of range %u-%u", + val_name, val, min_val, max_val); + return -EUCLEAN; + } + + return 0; +} + +static int check_dquot_block_header(struct qtree_mem_dqinfo *info, + struct qt_disk_dqdbheader *dh) +{ + int err = 0; + + err = do_check_range(info->dqi_sb, "dqdh_next_free", + le32_to_cpu(dh->dqdh_next_free), 0, + info->dqi_blocks - 1); + if (err) + return err; + err = do_check_range(info->dqi_sb, "dqdh_prev_free", + le32_to_cpu(dh->dqdh_prev_free), 0, + info->dqi_blocks - 1); + + return err; +} + /* Remove empty block from list and return it */ static int get_free_dqblk(struct qtree_mem_dqinfo *info) { @@ -93,6 +122,9 @@ static int get_free_dqblk(struct qtree_m ret = read_blk(info, blk, buf); if (ret < 0) goto out_buf; + ret = check_dquot_block_header(info, dh); + if (ret) + goto out_buf; info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free); } else { @@ -240,6 +272,9 @@ static uint find_free_dqentry(struct qtr *err = read_blk(info, blk, buf); if (*err < 0) goto out_buf; + *err = check_dquot_block_header(info, dh); + if (*err) + goto out_buf; } else { blk = get_free_dqblk(info); if ((int)blk < 0) { @@ -432,6 +467,9 @@ static int free_dqentry(struct qtree_mem goto out_buf; } dh = (struct qt_disk_dqdbheader *)buf; + ret = check_dquot_block_header(info, dh); + if (ret) + goto out_buf; le16_add_cpu(&dh->dqdh_entries, -1); if (!le16_to_cpu(dh->dqdh_entries)) { /* Block got free? */ ret = remove_free_dqentry(info, buf, blk);