Re: [patch 5/9] x86/ioport: Reduce ioperm impact for sane usage further

From: Willy Tarreau
Date: Thu Nov 07 2019 - 11:59:29 EST


On Thu, Nov 07, 2019 at 10:45:09AM -0600, Eric W. Biederman wrote:
> Further a quick look shows that dosemu uses ioperm in a fine grained
> manner. From memory it would allow a handful of ports to allow directly
> accessing a device and depended on the rest of the port accesses to be
> disallowed so it could trap and emulate them.
>
> So yes I do believe making ioperm ioperm(all) will break userspace.

OK, and I must confess I almost forgot about dosemu, that's a good point!

Thanks,
Willy