udf: Verify inode link counts before performing rename

During rename, we are updating link counts of various inodes either when
rename deletes target or when moving directory across directories.
Verify involved link counts are sane so that we don't trip warnings in
VFS.

Reported-by: syzbot+3ff7365dc04a6bcafa66@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2024-11-26 12:55:12 +01:00
parent c5566903af
commit 6756af923e

View File

@ -791,8 +791,18 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir,
retval = -ENOTEMPTY;
if (!empty_dir(new_inode))
goto out_oiter;
retval = -EFSCORRUPTED;
if (new_inode->i_nlink != 2)
goto out_oiter;
}
retval = -EFSCORRUPTED;
if (old_dir->i_nlink < 3)
goto out_oiter;
is_dir = true;
} else if (new_inode) {
retval = -EFSCORRUPTED;
if (new_inode->i_nlink < 1)
goto out_oiter;
}
if (is_dir && old_dir != new_dir) {
retval = udf_fiiter_find_entry(old_inode, &dotdot_name,