From nobody Fri Dec 19 16:00:40 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD062ECAAA1 for ; Mon, 24 Oct 2022 12:54:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234529AbiJXMyd (ORCPT ); Mon, 24 Oct 2022 08:54:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234817AbiJXMyG (ORCPT ); Mon, 24 Oct 2022 08:54:06 -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 9153895B3; Mon, 24 Oct 2022 05:14:23 -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 657C8612D5; Mon, 24 Oct 2022 12:06:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7AC2BC433D6; Mon, 24 Oct 2022 12:06:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666613179; bh=nThvYlMCokv6gXc3/lKR2WMS3hubHiyAx5INGUND/qw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gdibjvGothA0ZsTD0B3zBYEm0xxwMa1p5ocdescMIy+kBXjS8XdmgtrHhZZoBGBlB K3SIRDfaQNsKB2i6ySbfkjZcTnYyNo8b086pfuTY1s55hH5mxD6GP398cFFGhOkYT9 ax0Sihhpl7LCYGr0n/TdK3C/MXism4KUc7QvW3Hw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ryusuke Konishi , syzbot+b8c672b0e22615c80fe0@syzkaller.appspotmail.com, Khalid Masum , Andrew Morton Subject: [PATCH 5.4 039/255] nilfs2: fix use-after-free bug of struct nilfs_root Date: Mon, 24 Oct 2022 13:29:09 +0200 Message-Id: <20221024113003.729627889@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113002.471093005@linuxfoundation.org> References: <20221024113002.471093005@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Ryusuke Konishi commit d325dc6eb763c10f591c239550b8c7e5466a5d09 upstream. If the beginning of the inode bitmap area is corrupted on disk, an inode with the same inode number as the root inode can be allocated and fail soon after. In this case, the subsequent call to nilfs_clear_inode() on that bogus root inode will wrongly decrement the reference counter of struct nilfs_root, and this will erroneously free struct nilfs_root, causing kernel oopses. This fixes the problem by changing nilfs_new_inode() to skip reserved inode numbers while repairing the inode bitmap. Link: https://lkml.kernel.org/r/20221003150519.39789-1-konishi.ryusuke@gmai= l.com Signed-off-by: Ryusuke Konishi Reported-by: syzbot+b8c672b0e22615c80fe0@syzkaller.appspotmail.com Reported-by: Khalid Masum Tested-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/inode.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -340,6 +340,7 @@ struct inode *nilfs_new_inode(struct ino struct inode *inode; struct nilfs_inode_info *ii; struct nilfs_root *root; + struct buffer_head *bh; int err =3D -ENOMEM; ino_t ino; =20 @@ -355,11 +356,26 @@ struct inode *nilfs_new_inode(struct ino ii->i_state =3D BIT(NILFS_I_NEW); ii->i_root =3D root; =20 - err =3D nilfs_ifile_create_inode(root->ifile, &ino, &ii->i_bh); + err =3D nilfs_ifile_create_inode(root->ifile, &ino, &bh); if (unlikely(err)) goto failed_ifile_create_inode; /* reference count of i_bh inherits from nilfs_mdt_read_block() */ =20 + if (unlikely(ino < NILFS_USER_INO)) { + nilfs_msg(sb, KERN_WARNING, + "inode bitmap is inconsistent for reserved inodes"); + do { + brelse(bh); + err =3D nilfs_ifile_create_inode(root->ifile, &ino, &bh); + if (unlikely(err)) + goto failed_ifile_create_inode; + } while (ino < NILFS_USER_INO); + + nilfs_msg(sb, KERN_INFO, + "repaired inode bitmap for reserved inodes"); + } + ii->i_bh =3D bh; + atomic64_inc(&root->inodes_count); inode_init_owner(inode, dir, mode); inode->i_ino =3D ino;