From: Dominique Martinet asmadeus@codewreck.org
[ Upstream commit 391c18cf776eb4569ecda1f7794f360fe0a45a26 ]
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: Stefano Stabellini sstabellini@kernel.org Reviewed-by: Christian Schoenebeck linux_oss@crudebyte.com Link: https://lkml.kernel.org/r/20221118135542.63400-1-asmadeus@codewreck.org Signed-off-by: Dominique Martinet asmadeus@codewreck.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/9p/trans_xen.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c index 432ac5a16f2e..6c8a33f98f09 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -231,6 +231,14 @@ 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;
@@ -240,6 +248,7 @@ 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;