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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 240C2C433E5 for ; Mon, 22 Mar 2021 12:59:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E8CA3619BD for ; Mon, 22 Mar 2021 12:59:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233598AbhCVM65 (ORCPT ); Mon, 22 Mar 2021 08:58:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:40974 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232553AbhCVMrx (ORCPT ); Mon, 22 Mar 2021 08:47:53 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B57E8619C9; Mon, 22 Mar 2021 12:43:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1616417021; bh=6g9Abcz7mFgQhFYcQowb+Yn5uclrxsDrS+7thxexddI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cg4myWYexhHEnKc5iYSYVfvUvHpZV4YIcqE0+KvOAlfWc9smgL9RSicl7fWAipJVs 83UE8T0qVb850wKcqEDaa0g2uCMjYUCF2KEEzxTt51OXEzyvxJvS+cijyIoYFLoc7B gQwZ21bqEI1KjA76okA/RRdf+VzG6zcZvqGRXdkA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+98b881fdd8ebf45ab4ae@syzkaller.appspotmail.com, stable@kernel.org, "zhangyi (F)" , Theodore Tso Subject: [PATCH 5.4 55/60] ext4: do not try to set xattr into ea_inode if value is empty Date: Mon, 22 Mar 2021 13:28:43 +0100 Message-Id: <20210322121924.192489561@linuxfoundation.org> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20210322121922.372583154@linuxfoundation.org> References: <20210322121922.372583154@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: zhangyi (F) commit 6b22489911b726eebbf169caee52fea52013fbdd upstream. Syzbot report a warning that ext4 may create an empty ea_inode if set an empty extent attribute to a file on the file system which is no free blocks left. WARNING: CPU: 6 PID: 10667 at fs/ext4/xattr.c:1640 ext4_xattr_set_entry+0x10f8/0x1114 fs/ext4/xattr.c:1640 ... Call trace: ext4_xattr_set_entry+0x10f8/0x1114 fs/ext4/xattr.c:1640 ext4_xattr_block_set+0x1d0/0x1b1c fs/ext4/xattr.c:1942 ext4_xattr_set_handle+0x8a0/0xf1c fs/ext4/xattr.c:2390 ext4_xattr_set+0x120/0x1f0 fs/ext4/xattr.c:2491 ext4_xattr_trusted_set+0x48/0x5c fs/ext4/xattr_trusted.c:37 __vfs_setxattr+0x208/0x23c fs/xattr.c:177 ... Now, ext4 try to store extent attribute into an external inode if ext4_xattr_block_set() return -ENOSPC, but for the case of store an empty extent attribute, store the extent entry into the extent attribute block is enough. A simple reproduce below. fallocate test.img -l 1M mkfs.ext4 -F -b 2048 -O ea_inode test.img mount test.img /mnt dd if=/dev/zero of=/mnt/foo bs=2048 count=500 setfattr -n "user.test" /mnt/foo Reported-by: syzbot+98b881fdd8ebf45ab4ae@syzkaller.appspotmail.com Fixes: 9c6e7853c531 ("ext4: reserve space for xattr entries/names") Cc: stable@kernel.org Signed-off-by: zhangyi (F) Link: https://lore.kernel.org/r/20210305120508.298465-1-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -2415,7 +2415,7 @@ retry_inode: * external inode if possible. */ if (ext4_has_feature_ea_inode(inode->i_sb) && - !i.in_inode) { + i.value_len && !i.in_inode) { i.in_inode = 1; goto retry_inode; }