Re: [PATCH v1 1/6] virtio console: Harden multiport against invalid host input - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>, Arnd Bergmann <arnd@arndb.de>,
	mst@redhat.com, Amit Shah <amit@kernel.org>,
	linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	elena.reshetova@intel.com, kirill.shutemov@linux.intel.com
Subject: Re: [PATCH v1 1/6] virtio console: Harden multiport against invalid host input
Date: Thu, 19 Jan 2023 20:18:12 +0100	[thread overview]
Message-ID: <Y8mXdFms3CzPnW+6@kroah.com> (raw)
In-Reply-To: <87fsc6qrvx.fsf@ubik.fi.intel.com>

On Thu, Jan 19, 2023 at 08:52:02PM +0200, Alexander Shishkin wrote:
> Greg Kroah-Hartman <gregkh@linuxfoundation.org> writes:
> 
> > On Thu, Jan 19, 2023 at 03:57:16PM +0200, Alexander Shishkin wrote:
> >> From: Andi Kleen <ak@linux.intel.com>
> >> 
> >> --- a/drivers/char/virtio_console.c
> >> +++ b/drivers/char/virtio_console.c
> >> @@ -1843,6 +1843,9 @@ static int init_vqs(struct ports_device *portdev)
> >>  	int err;
> >>  
> >>  	nr_ports = portdev->max_nr_ports;
> >> +	if (use_multiport(portdev) && nr_ports < 1)
> >> +		return -EINVAL;
> >> +
> >>  	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
> >>  
> >>  	vqs = kmalloc_array(nr_queues, sizeof(struct virtqueue *), GFP_KERNEL);
> >> -- 
> >> 2.39.0
> >> 
> >
> > Why did I only get a small subset of these patches?
> 
> I did what get_maintainer told me. Would you like to be CC'd on the
> whole thing?

If you only cc: me on a portion of the series, I guess you only want me
to apply a portion of it?  if so, why is it a longer series?

> > And why is the whole thread not on lore.kernel.org?
> 
> That is a mystery, some wires got crossed between my smtp and vger. I
> bounced the series to lkml just now and at least some of it seems to
> have landed on lore.
> 
> > And the term "hardening" is marketing fluff.   Just say, "properly parse
> > input" or something like that, as what you are doing is fixing
> > assumptions about the data here, not causing anything to be more (or
> > less) secure.
> >
> > But, this still feels wrong.  Why is this happening here, in init_vqs()
> > and not in the calling function that already did a bunch of validation
> > of the ports and the like?  Are those checks not enough?  if not, fix it
> > there, don't spread it out all over the place...
> 
> Good point! And there happens to already be 28962ec595d70 that takes
> care of exactly this case. I totally missed it.

So this series is not needed?  Or just this one?

greg k-h
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