From 21a87d88c2253350e115029f14fe2a10a7e6c856 Mon Sep 17 00:00:00 2001

From: Ryusuke Konishi <konishi.ryusuke@gmail.com>

Date: Sun, 2 Oct 2022 12:08:04 +0900

Subject: [PATCH] nilfs2: fix NULL pointer dereference at nilfs_bmap_lookup_at_level()

Git-commit: 21a87d88c2253350e115029f14fe2a10a7e6c856

Patch-mainline: v6.1-rc1

References: CVE-2022-3621 bsc#1204574

If the i_mode field in inode of metadata files is corrupted on disk, it

can cause the initialization of bmap structure, which should have been

called from nilfs_read_inode_common(), not to be called.  This causes a

lockdep warning followed by a NULL pointer dereference at

nilfs_bmap_lookup_at_level().

This patch fixes these issues by adding a missing sanitiy check for the

i_mode field of metadata file's inode.

Link: https://lkml.kernel.org/r/20221002030804.29978-1-konishi.ryusuke@gmail.com

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>

Reported-by: syzbot+2b32eb36c1a825b7a74c@syzkaller.appspotmail.com

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>

Cc: <stable@vger.kernel.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 fs/nilfs2/inode.c | 2 ++

 1 file changed, 2 insertions(+)

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c

index b074144f6f83..232dd7b6cca1 100644

--- a/fs/nilfs2/inode.c

+++ b/fs/nilfs2/inode.c

@@ -455,6 +455,8 @@ int nilfs_read_inode_common(struct inode *inode,

 	inode->i_atime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);

 	inode->i_ctime.tv_nsec = le32_to_cpu(raw_inode->i_ctime_nsec);

 	inode->i_mtime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);

+	if (nilfs_is_metadata_file_inode(inode) && !S_ISREG(inode->i_mode))

+		return -EIO; /* this inode is for metadata and corrupted */

 	if (inode->i_nlink == 0)

 		return -ESTALE; /* this inode is deleted */

-- 

2.35.3