From: Jan Beulich jbeulich@suse.com
commit f63c2c2032c2e3caad9add3b82cc6e91c376fd26 upstream.
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 Signed-off-by: Juergen Gross jgross@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/xen-netfront.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1094,8 +1094,10 @@ static int xennet_get_responses(struct n } } rcu_read_unlock(); -next: + __skb_queue_tail(list, skb); + +next: if (!(rx->flags & XEN_NETRXF_more_data)) break;