Subject: Re: [PATCH iwl-net 1/3] idpf: fix memory leaks and crashes while performing a soft reset

From: Simon Horman <[email-masked]>
Date: Tue, 30 Jul 2024 17:37:07 +0100

On Mon, Jul 29, 2024 at 10:54:50AM +0200, Alexander Lobakin wrote:
> From: Simon Horman <[email-masked]>
> Date: Fri, 26 Jul 2024 17:09:54 +0100
> 
> > On Wed, Jul 24, 2024 at 03:40:22PM +0200, Alexander Lobakin wrote:
> >> The second tagged commit introduced a UAF, as it removed restoring
> >> q_vector->vport pointers after reinitializating the structures.
> >> This is due to that all queue allocation functions are performed here
> >> with the new temporary vport structure and those functions rewrite
> >> the backpointers to the vport. Then, this new struct is freed and
> >> the pointers start leading to nowhere.
> 
> [...]
> 
> >>  err_reset:
> >> -	idpf_vport_queues_rel(new_vport);
> >> +	idpf_send_add_queues_msg(vport, vport->num_txq, vport->num_complq,
> >> +				 vport->num_rxq, vport->num_bufq);
> >> +
> >> +err_open:
> >> +	if (current_state == __IDPF_VPORT_UP)
> >> +		idpf_vport_open(vport);
> > 
> > Hi Alexander,
> > 
> > Can the system end up in an odd state if this call to idpf_vport_open(), or
> > the one above, fails. Likewise if the above call to
> > idpf_send_add_queues_msg() fails.
> 
> Adding the queues with the parameters that were before changing them
> almost can't fail. But if any of these two fails, it really will be in
> an odd state...

Thanks for the clarification, this is my concern.

> Perhaps we need to do a more powerful reset then? Can we somehow tell
> the kernel that in fact our iface is down, so that the user could try
> to enable it manually once again?
> Anyway, feels like a separate series or patch to -next, what do you think?

Yes, sure. I agree that this patch improves things, and more extreme
corner cases can be addressed separately.

With the above in mind, I'm happy with this patch.

Reviewed-by: Simon Horman <[email-masked]>