RE: [PATCH 4.4 29/57] RDMA/uverbs: Check port number supplied by user verbs cmds

[Ismail, Mustafa]

> -----Original Message-----
> From: Greg Kroah-Hartman [mailto:gregkh@xxxxxxxxxxxxxxxxxxx]
> Sent: Thursday, July 13, 2017 11:26 AM
> To: Ismail, Mustafa <mustafa.ismail@xxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx;
> stable@xxxxxxxxxxxxxxx; Yevgeny Kliteynik <kliteyn@xxxxxxxxxxxx>;
> Tziporet Koren <tziporet@xxxxxxxxxxxx>; Alex Polak
> <alexpo@xxxxxxxxxxxx>; Boris Pismenny <borisp@xxxxxxxxxxxx>; Leon
> Romanovsky <leon@xxxxxxxxxx>; Doug Ledford <dledford@xxxxxxxxxx>
> Subject: Re: [PATCH 4.4 29/57] RDMA/uverbs: Check port number supplied
> by user verbs cmds
> 
> On Thu, Jul 13, 2017 at 03:54:28PM +0000, Ismail, Mustafa wrote:
> > > Subject: [PATCH 4.4 29/57] RDMA/uverbs: Check port number supplied
> > > by user verbs cmds
> > >
> > > 4.4-stable review patch.  If anyone has any objections, please let me
> know.
> >
> > Yes, this breaks modify qp.
> > See https://patchwork.kernel.org/patch/9830663/
> 
> I don't understand this response at all, sorry.
> 
> What should I do about this?  Is this patch alone a problem?  Is there some
> other patch I should apply that is in Linus's tree?  Where is the problem,
> only in this old release?
> 
Applying this patch will break RDMA functionality with respect to modify_qp.
Specifically this part:
+	if (cmd.port_num < rdma_start_port(ib_dev) ||
+	    cmd.port_num > rdma_end_port(ib_dev))
+		return -EINVAL;
+
The cmd.port_num is only valid if (cmd->base.attr_mask & IB_QP_PORT).
So the above can be fixed with:
	if ((cmd->base.attr_mask & IB_QP_PORT) && 
	    (cmd.port_num < rdma_start_port(ib_dev) ||
	    cmd.port_num > rdma_end_port(ib_dev)))
		return -EINVAL;

A version of this patch is in Linus's tree and it has the same problem:
commit 5ecce4c9b17bed4dc9cb58bfb10447307569b77b    "RDMA/uverbs: Check port number supplied by user verbs cmds"

We will be submitting a patch to fix this shortly.

Mustafa