[PATCH 1/2] iouring: one capable call per iouring instance

[Jeff Moyer]

Jens Axboe <axboe at kernel.dk> writes:

> On 12/4/23 11:40 AM, Jeff Moyer wrote:
>> Finally, as Jens mentioned, I would expect dropping priviliges to, you
>> know, drop privileges.  I don't think a commit message is going to be
>> enough documentation for a change like this.
>
> Only thing I can think of here is to cache the state in
> task->io_uring->something, and then ensure those are invalidated
> whenever caps change.

I looked through the capable() code, and there is no way that I could
find to be notified of changes.

> It's one of those cases where that's probably only done once, but we
> do need to be able to catch it. Not convinced that caching it at ring
> creation is sane enough, even if it is kind of like opening devices
> before privs are dropped where you could not otherwise re-open them
> later on.

Agreed.

-Jeff