Re: [PATCH net v3 2/2] net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: 2021-03-09 14:31:15
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lkml, virtualization
On Tue, Mar 9, 2021 at 6:32 AM Balazs Nemeth [off-list ref] wrote:
A packet with skb_inner_network_header(skb) == skb_network_header(skb) and ETH_P_MPLS_UC will prevent mpls_gso_segment from pulling any headers from the packet. Subsequently, the call to skb_mac_gso_segment will again call mpls_gso_segment with the same packet leading to an infinite loop. In addition, ensure that the header length is a multiple of four, which should hold irrespective of the number of stacked labels. Signed-off-by: Balazs Nemeth <redacted>
Acked-by: Willem de Bruijn <willemb@google.com> The compiler will convert that modulo into a cheap & (ETH_HLEN - 1) test for this constant.