Re: [PATCH 0/2] fs: fix capable() call in simple_xattr_list()

[Christian Brauner]

On Thu, Sep 01, 2022 at 05:26:30PM +0200, Ondrej Mosnacek wrote:
> The goal of these patches is to avoid calling capable() unconditionally
> in simple_xattr_list(), which causes issues under SELinux (see
> explanation in the second patch).
> 
> The first patch tries to make this change safer by converting
> simple_xattrs to use the RCU mechanism, so that capable() is not called
> while the xattrs->lock is held. I didn't find evidence that this is an
> issue in the current code, but it can't hurt to make that change
> either way (and it was quite straightforward).

Hey Ondrey,

There's another patchset I'd like to see first which switches from a
linked list to an rbtree to get rid of performance issues in this code
that can be used to dos tmpfs in containers:

https://lore.kernel.org/lkml/d73bd478-e373-f759-2acb-2777f6bba06f@xxxxxxxxxx

I don't think Vasily has time to continue with this so I'll just pick it
up hopefully this or the week after LPC.

Christian