summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorAntoine Tenart <atenart@kernel.org>2024-03-26 14:34:01 +0300
committerDavid S. Miller <davem@davemloft.net>2024-03-29 14:30:44 +0300
commit64235eabc4b5b18c507c08a1f16cdac6c5661220 (patch)
tree5d79a26b369c321f027319943b573156f4a0f121
parentf0b8c30345565344df2e33a8417a27503589247d (diff)
downloadlinux-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.c6
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;