Thread (13 messages) 13 messages, 5 authors, 2021-03-30

Re: [PATCH 3/3] scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()

From: Andrea Parri <parri.andrea@gmail.com>
Date: 2021-03-30 09:09:21
Also in: linux-scsi, lkml

Hi Olaf,

On Mon, Mar 29, 2021 at 06:37:21PM +0200, Olaf Hering wrote:
On Thu, Dec 17, Andrea Parri (Microsoft) wrote:
quoted
Check that the packet is of the expected size at least, don't copy data
past the packet.
quoted
+		if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) -
+				stor_device->vmscsi_size_delta) {
+			dev_err(&device->device, "Invalid packet len\n");
+			continue;
+		}
+
Sorry for being late:

It might be just cosmetic, but should this check be done prior the call to vmbus_request_addr()?
TBH, I'm not immediately seeing why it 'should'; it could make sense to move
the check on the packet data length.

Unrelated: my copy of vmbus_request_addr() can return 0, which is apparently not handled by this loop in storvsc_on_channel_callback().
Indeed, IDs of 0 are reserved for so called unsolicited messages; I think we
should check that storvsc_on_io_completion() is not called on such messages.

Thanks,
  Andrea
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