Re: [PATCH 1/3] VFS: introduce MAY_ACT_AS_OWNER

[David Howells]

NeilBrown <neilb@xxxxxxxx> wrote:

> diff --git a/fs/afs/security.c b/fs/afs/security.c
> index 81dfedb7879f..ac2e39de8bff 100644
> --- a/fs/afs/security.c
> +++ b/fs/afs/security.c
> @@ -349,6 +349,16 @@ int afs_permission(struct inode *inode, int mask)
>  	if (mask & MAY_NOT_BLOCK)
>  		return -ECHILD;
>  
> +	/* Short-circuit for owner */
> +	if (mask & MAY_ACT_AS_OWNER) {
> +		if (inode_owner_or_capable(inode))

You don't know that inode->i_uid in meaningful.  You may have noticed that
afs_permission() ignores i_uid and i_gid entirely.  It queries the server (if
this information is not otherwise cached) to ask what permits the user is
granted - where the user identity is defined by the key returned from
afs_request_key()[*].

So, NAK for the afs piece.

David

[*] If there's no appropriate key, anonymous permits will be used.