From: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Date: Sun, 2 Oct 2022 03:08:04 +0000 (+0900)
Subject: nilfs2: fix NULL pointer dereference at nilfs_bmap_lookup_at_level()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1e512c65b4adcdbdf7aead052f2162b079cc7f55;p=linux.git

nilfs2: fix NULL pointer dereference at nilfs_bmap_lookup_at_level()

commit 21a87d88c2253350e115029f14fe2a10a7e6c856 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 2466f8b8be95c..35bc52d453a97 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -444,6 +444,8 @@ 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 */