From nobody Fri Dec 19 19:00:11 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 281D0C433FE for ; Thu, 13 Oct 2022 17:58:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230003AbiJMR6U (ORCPT ); Thu, 13 Oct 2022 13:58:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230157AbiJMR5Z (ORCPT ); Thu, 13 Oct 2022 13:57:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B8A467C97; Thu, 13 Oct 2022 10:56:23 -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 06B31618FB; Thu, 13 Oct 2022 17:54:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15D5FC433D6; Thu, 13 Oct 2022 17:54:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1665683681; bh=jk4n9BSYyxD6hRGgHsVIYR6ysfCma4ji0iOCcXKE4z8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DNpjiB8ngGDhbGNeH94DKYe0Pe6QZTaUPGWNpdEBnvKDAO72qUdHXRmJG67gZ42pg BxGH2SnksOuhiCR3+f83RanBInrME64ZjxJWaZjv28QJlKYSR9StCRwfinhmrzVZlv c3LoPx/97sSCP7FwM3oUqHomSbGGJBtDwmdm87D0= 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 5.10 02/54] nilfs2: fix use-after-free bug of struct nilfs_root Date: Thu, 13 Oct 2022 19:51:56 +0200 Message-Id: <20221013175147.403694752@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221013175147.337501757@linuxfoundation.org> References: <20221013175147.337501757@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 | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -332,6 +332,7 @@ 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 @@ -347,11 +348,25 @@ 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_warn(sb, + "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_info(sb, "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;