Re: [PATCH] kill suid bit only for regular files

[Andrew Morton <akpm@linux-foundation.org>]

On Sun, 19 Oct 2008 18:00:39 +0400 Dmitri Monakhov <dmonakhov@openvz.org> wrote:

> We don't have to do it because it is useless for non regular files.

Are we sure that should_remove_suid() is not and never will used for
directories?

> In fact block device may trigger this path without dentry->d_inode->i_mutex.

What's wrong with blockdevs triggering this path?

Better changelogs, please.

> Signed-off-by: Dmitri Monakhov <dmonakhov@openvz.org>
> ---
>  mm/filemap.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/mm/filemap.c b/mm/filemap.c
> index a2907d5..3d5a2e7 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1767,7 +1767,7 @@ int should_remove_suid(struct dentry *dentry)
>  	if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
>  		kill |= ATTR_KILL_SGID;
>  
> -	if (unlikely(kill && !capable(CAP_FSETID)))
> +	if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
>  		return kill;
>  
>  	return 0;