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 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 01112C10F13 for ; Fri, 12 Apr 2019 02:05:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA4D920869 for ; Fri, 12 Apr 2019 02:05:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726748AbfDLCFy (ORCPT ); Thu, 11 Apr 2019 22:05:54 -0400 Received: from szxga08-in.huawei.com ([45.249.212.255]:56102 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726640AbfDLCFy (ORCPT ); Thu, 11 Apr 2019 22:05:54 -0400 Received: from DGGEMM405-HUB.china.huawei.com (unknown [172.30.72.56]) by Forcepoint Email with ESMTP id 7D6E785E20A520AADF64; Fri, 12 Apr 2019 10:05:50 +0800 (CST) Received: from dggeme763-chm.china.huawei.com (10.3.19.109) by DGGEMM405-HUB.china.huawei.com (10.3.20.213) with Microsoft SMTP Server (TLS) id 14.3.408.0; Fri, 12 Apr 2019 10:05:48 +0800 Received: from [10.134.22.195] (10.134.22.195) by dggeme763-chm.china.huawei.com (10.3.19.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1591.10; Fri, 12 Apr 2019 10:05:48 +0800 Subject: Re: [PATCH v5] f2fs: fix to avoid accessing xattr across the boundary To: Randall Huang , , , References: <20190411082646.169977-1-huangrandall@google.com> From: Chao Yu Message-ID: <0cef5922-c72a-2ce5-91ff-06b1b004451a@huawei.com> Date: Fri, 12 Apr 2019 10:05:47 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190411082646.169977-1-huangrandall@google.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-ClientProxiedBy: dggeme711-chm.china.huawei.com (10.1.199.107) To dggeme763-chm.china.huawei.com (10.3.19.109) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/4/11 16:26, Randall Huang wrote: > When we traverse xattr entries via __find_xattr(), > if the raw filesystem content is faked or any hardware failure occurs, > out-of-bound error can be detected by KASAN. > Fix the issue by introducing boundary check. > > [ 38.402878] c7 1827 BUG: KASAN: slab-out-of-bounds in f2fs_getxattr+0x518/0x68c > [ 38.402891] c7 1827 Read of size 4 at addr ffffffc0b6fb35dc by task > [ 38.402935] c7 1827 Call trace: > [ 38.402952] c7 1827 [] dump_backtrace+0x0/0x6bc > [ 38.402966] c7 1827 [] show_stack+0x20/0x2c > [ 38.402981] c7 1827 [] dump_stack+0xfc/0x140 > [ 38.402995] c7 1827 [] print_address_description+0x80/0x2d8 > [ 38.403009] c7 1827 [] kasan_report_error+0x198/0x1fc > [ 38.403022] c7 1827 [] kasan_report_error+0x0/0x1fc > [ 38.403037] c7 1827 [] __asan_load4+0x1b0/0x1b8 > [ 38.403051] c7 1827 [] f2fs_getxattr+0x518/0x68c > [ 38.403066] c7 1827 [] f2fs_xattr_generic_get+0xb0/0xd0 > [ 38.403080] c7 1827 [] __vfs_getxattr+0x1f4/0x1fc > [ 38.403096] c7 1827 [] inode_doinit_with_dentry+0x360/0x938 > [ 38.403109] c7 1827 [] selinux_d_instantiate+0x2c/0x38 > [ 38.403123] c7 1827 [] security_d_instantiate+0x68/0x98 > [ 38.403136] c7 1827 [] d_splice_alias+0x58/0x348 > [ 38.403149] c7 1827 [] f2fs_lookup+0x608/0x774 > [ 38.403163] c7 1827 [] lookup_slow+0x1e0/0x2cc > [ 38.403177] c7 1827 [] walk_component+0x160/0x520 > [ 38.403190] c7 1827 [] path_lookupat+0x110/0x2b4 > [ 38.403203] c7 1827 [] filename_lookup+0x1d8/0x3a8 > [ 38.403216] c7 1827 [] user_path_at_empty+0x54/0x68 > [ 38.403229] c7 1827 [] SyS_getxattr+0xb4/0x18c > [ 38.403241] c7 1827 [] el0_svc_naked+0x34/0x38 > > Bug: 126558260 > > Signed-off-by: Randall Huang Looks good to me now. :) Reviewed-by: Chao Yu > + unsigned int xattr_nid_size = xnid ? VALID_XATTR_BLOCK_SIZE : 0; Nitpick, xnode_size or xattr_node_size will be better than xattr_nid_size? Maybe Jaegeuk can help to change this when merging this patch, no new version patch needed. Thanks,