Re: [PATCH v9 2/3] scsi: storvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening

[Wei Liu]

On Fri, Nov 13, 2020 at 10:39:33PM +0100, Andrea Parri wrote:
> On Fri, Nov 13, 2020 at 06:54:24PM +0000, Wei Liu wrote:
> > On Fri, Nov 13, 2020 at 11:33:27AM +0000, Wei Liu wrote:
> > > On Mon, Nov 09, 2020 at 11:04:01AM +0100, Andrea Parri (Microsoft) wrote:
> > > > From: Andres Beltran <lkmlabelt@xxxxxxxxx>
> > > > 
> > > > Currently, pointers to guest memory are passed to Hyper-V as
> > > > transaction IDs in storvsc. In the face of errors or malicious
> > > > behavior in Hyper-V, storvsc should not expose or trust the transaction
> > > > IDs returned by Hyper-V to be valid guest memory addresses. Instead,
> > > > use small integers generated by vmbus_requestor as requests
> > > > (transaction) IDs.
> > > > 
> > > > Signed-off-by: Andres Beltran <lkmlabelt@xxxxxxxxx>
> > > > Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> > > > Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> > > > Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> > > > Cc: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxx>
> > > > Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
> > > > Cc: linux-scsi@xxxxxxxxxxxxxxx
> > > 
> > > Reviewed-by: Wei Liu <wl@xxxxxxx>
> > 
> > Martin already gave his ack back in July. I guess nothing substantial
> > changed so it should have been carried over?
> 
> The only change here happened in v7 and consisted in moving the
> allocation of the request IDs from the VSC code down into the core
> vmbus_sendpacket()&co functions.  As mentioned in v7 cover letter,
> this change was applied to ensure that the allocation in question
> is performed after the packet is copied into the ring buffer.  On
> a positive note, this change greatly reduced the diff of this and
> the following (NetVSC) patches.

Martin and James, are you happy with this change? I would assume you are
because that means this patch to storvsc is leaner.

Please give an explicit ack if you can. Thanks.

Wei.

> 
>   Andrea