Patch-mainline: 5.19-rc6
Git-commit: f63c2c2032c2e3caad9add3b82cc6e91c376fd26
References: bsc#1200763, CVE-2022-33743, XSA-405
From: Jan Beulich <jbeulich@suse.com>
Date: Fri, 1 Jul 2022 08:56:52 +0200
Subject: [PATCH] xen-netfront: restore __skb_queue_tail() positioning in
 xennet_get_responses()

The commit referenced below moved the invocation past the "next" label,
without any explanation. In fact this allows misbehaving backends undue
control over the domain the frontend runs in, as earlier detected errors
require the skb to not be freed (it may be retained for later processing
via xennet_move_rx_slot(), or it may simply be unsafe to have it freed).

This is CVE-2022-33743 / XSA-405.

Fixes: 6c5aa6fc4def ("xen networking: add basic XDP support for xen-netfront")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
---
 drivers/net/xen-netfront.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 87f6df77bfbf..2409007f1fd9 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1092,8 +1092,10 @@ static int xennet_get_responses(struct netfront_queue *queue,
 			}
 		}
 		rcu_read_unlock();
-next:
+
 		__skb_queue_tail(list, skb);
+
+next:
 		if (!(rx->flags & XEN_NETRXF_more_data))
 			break;
 
-- 
2.35.3