Re: [PATCH net] net: drop bad gso csum_start and offset in virtio_net_hdr
From: Eric Dumazet <edumazet@google.com>
Date: 2024-07-26 07:00:46
Also in:
stable
On Fri, Jul 26, 2024 at 4:34 AM Willem de Bruijn [off-list ref] wrote:
From: Willem de Bruijn <willemb@google.com>
...
quoted hunk ↗ jump to hunk
/* Kernel has a special handling for GSO_BY_FRAGS. */diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index 4b791e74529e1..9e49ffcc77071 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c@@ -140,6 +140,9 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb, if (thlen < sizeof(*th)) goto out; + if (unlikely(skb->csum_start != skb->transport_header)) + goto out; +
Using skb_transport_header() will make sure DEBUG_NET_WARN_ON_ONCE()
will fire for debug kernels,
with no additional costs for non debug kernels (compiler will generate
not use skb->head at all)
if (unlikely(skb->csum_start != skb_transport_header(skb) - skb->head))
goto out;
(This will match the corresponding initialization in __tcp_v4_send_check())