diff options
| author | Antoine Tenart <atenart@kernel.org> | 2024-03-26 14:34:01 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2024-03-29 14:30:44 +0300 |
| commit | 64235eabc4b5b18c507c08a1f16cdac6c5661220 (patch) | |
| tree | 5d79a26b369c321f027319943b573156f4a0f121 | |
| parent | f0b8c30345565344df2e33a8417a27503589247d (diff) | |
| download | linux-64235eabc4b5b18c507c08a1f16cdac6c5661220.tar.xz | |
udp: prevent local UDP tunnel packets from being GROed
GRO has a fundamental issue with UDP tunnel packets as it can't detect
those in a foolproof way and GRO could happen before they reach the
tunnel endpoint. Previous commits have fixed issues when UDP tunnel
packets come from a remote host, but if those packets are issued locally
they could run into checksum issues.
If the inner packet has a partial checksum the information will be lost
in the GRO logic, either in udp4/6_gro_complete or in
udp_gro_complete_segment and packets will have an invalid checksum when
leaving the host.
Prevent local UDP tunnel packets from ever being GROed at the outer UDP
level.
Due to skb->encapsulation being wrongly used in some drivers this is
actually only preventing UDP tunnel packets with a partial checksum to
be GROed (see iptunnel_handle_offloads) but those were also the packets
triggering issues so in practice this should be sufficient.
Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
Fixes: 36707061d6ba ("udp: allow forwarding of plain (non-fraglisted) UDP GRO packets")
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/udp_offload.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 548476d78237..3498dd1d0694 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -559,6 +559,12 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb, */ NAPI_GRO_CB(skb)->is_flist = 0; if (!sk || !udp_sk(sk)->gro_receive) { + /* If the packet was locally encapsulated in a UDP tunnel that + * wasn't detected above, do not GRO. + */ + if (skb->encapsulation) + goto out; + if (skb->dev->features & NETIF_F_GRO_FRAGLIST) NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1; |