file_remove_suid() could mistakenly set S_NOSEC inode bit when root was
modifying the file. As a result following writes to the file by ordinary
user would avoid clearing suid or sgid bits.

Fix the bug by checking actual mode bits before setting S_NOSEC.

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Jan Kara 2015-05-21 16:05:52 +02:00 коммит произвёл Al Viro
Родитель c0c3a718e3
Коммит 2426f39100
1 изменённых файлов: 2 добавлений и 2 удалений

Просмотреть файл

@ -1706,8 +1706,8 @@ int file_remove_suid(struct file *file)
error = security_inode_killpriv(dentry);
if (!error && killsuid)
error = __remove_suid(dentry, killsuid);
if (!error && (inode->i_sb->s_flags & MS_NOSEC))
inode->i_flags |= S_NOSEC;
if (!error)
inode_has_no_xattr(inode);
return error;
}