From nobody Wed Apr 8 00:00:01 2026 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 D9ADCC38A2D for ; Wed, 26 Oct 2022 04:01:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232888AbiJZEBe (ORCPT ); Wed, 26 Oct 2022 00:01:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229750AbiJZEBY (ORCPT ); Wed, 26 Oct 2022 00:01:24 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 942F487FA7; Tue, 25 Oct 2022 21:01:21 -0700 (PDT) Received: from dggpeml500021.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Mxw8g05WJzHvHm; Wed, 26 Oct 2022 12:01:07 +0800 (CST) Received: from huawei.com (10.175.127.227) by dggpeml500021.china.huawei.com (7.185.36.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 26 Oct 2022 12:01:19 +0800 From: Baokun Li To: CC: , , , , , , , Subject: [PATCH v3 3/4] ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode Date: Wed, 26 Oct 2022 12:23:09 +0800 Message-ID: <20221026042310.3839669-4-libaokun1@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221026042310.3839669-1-libaokun1@huawei.com> References: <20221026042310.3839669-1-libaokun1@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpeml500021.china.huawei.com (7.185.36.21) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" There are many places that will get unhappy (and crash) when ext4_iget() returns a bad inode. However, if iget the boot loader inode, allows a bad inode to be returned, because the inode may not be initialized. This mechanism can be used to bypass some checks and cause panic. To solve this problem, we add a special iget flag EXT4_IGET_BAD. Only with this flag we'd be returning bad inode from ext4_iget(), otherwise we always return the error code if the inode is bad inode.(suggested by Jan Kara) Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Jason Yan --- fs/ext4/ext4.h | 3 ++- fs/ext4/inode.c | 8 +++++++- fs/ext4/ioctl.c | 3 ++- 3 files changed, 11 insertions(+), 3 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 8d5453852f98..2b574b143bde 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2964,7 +2964,8 @@ int do_journal_get_write_access(handle_t *handle, str= uct inode *inode, typedef enum { EXT4_IGET_NORMAL =3D 0, EXT4_IGET_SPECIAL =3D 0x0001, /* OK to iget a system inode */ - EXT4_IGET_HANDLE =3D 0x0002 /* Inode # is from a handle */ + EXT4_IGET_HANDLE =3D 0x0002, /* Inode # is from a handle */ + EXT4_IGET_BAD =3D 0x0004 /* Allow to iget a bad inode */ } ext4_iget_flags; =20 extern struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index ae3a836dd9d7..f767340229fd 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5043,8 +5043,14 @@ struct inode *__ext4_iget(struct super_block *sb, un= signed long ino, if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb)) ext4_error_inode(inode, function, line, 0, "casefold flag without casefold feature"); - brelse(iloc.bh); + if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD)) { + ext4_error_inode(inode, function, line, 0, + "bad inode without EXT4_IGET_BAD flag"); + ret =3D -EUCLEAN; + goto bad_inode; + } =20 + brelse(iloc.bh); unlock_new_inode(inode); return inode; =20 diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index ded535535b27..e0be8026c996 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -375,7 +375,8 @@ static long swap_inode_boot_loader(struct super_block *= sb, blkcnt_t blocks; unsigned short bytes; =20 - inode_bl =3D ext4_iget(sb, EXT4_BOOT_LOADER_INO, EXT4_IGET_SPECIAL); + inode_bl =3D ext4_iget(sb, EXT4_BOOT_LOADER_INO, + EXT4_IGET_SPECIAL | EXT4_IGET_BAD); if (IS_ERR(inode_bl)) return PTR_ERR(inode_bl); ei_bl =3D EXT4_I(inode_bl); --=20 2.31.1