Commit 391c18cf authored by Dominique Martinet's avatar Dominique Martinet
Browse files

9p/xen: check logical size for buffer size 



trans_xen did not check the data fits into the buffer before copying
from the xen ring, but we probably should.
Add a check that just skips the request and return an error to
userspace if it did not fit

Tested-by: default avatarStefano Stabellini <sstabellini@kernel.org>
Reviewed-by: default avatarChristian Schoenebeck <linux_oss@crudebyte.com>
Link: https://lkml.kernel.org/r/20221118135542.63400-1-asmadeus@codewreck.org


Signed-off-by: default avatarDominique Martinet <asmadeus@codewreck.org>
parent 6854fadb

net/9p/trans_xen.c

+9 −0
Original line number Diff line number Diff line
@@ -208,6 +208,14 @@ static void p9_xen_response(struct work_struct *work) 
			continue;

		}



		if (h.size > req->rc.capacity) {

			dev_warn(&priv->dev->dev,

				 "requested packet size too big: %d for tag %d with capacity %zd\n",

				 h.size, h.tag, req->rc.capacity);

			req->status = REQ_STATUS_ERROR;

			goto recv_error;

		}



		memcpy(&req->rc, &h, sizeof(h));

		req->rc.offset = 0;
@@ -217,6 +225,7 @@ static void p9_xen_response(struct work_struct *work) 
				     masked_prod, &masked_cons,

				     XEN_9PFS_RING_SIZE(ring));



recv_error:

		virt_mb();

		cons += h.size;

		ring->intf->in_cons = cons;