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Commit fe801568 authored by Ryusuke Konishi's avatar Ryusuke Konishi Committed by Greg Kroah-Hartman
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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: default avatarRyusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: default avatar <syzbot+2b32eb36c1a825b7a74c@syzkaller.appspotmail.com>
Reported-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: default avatarRyusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1a476214

fs/nilfs2/inode.c

+2 −0
Original line number Diff line number Diff line
@@ -451,6 +451,8 @@ 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 */