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-rw-r--r--include/net/udp.h23
-rw-r--r--net/ipv4/udp.c2
-rw-r--r--net/ipv6/udp.c1
3 files changed, 26 insertions, 0 deletions
diff --git a/include/net/udp.h b/include/net/udp.h
index d4d064c59232..adf2ff8ac87c 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -515,6 +515,29 @@ static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
return segs;
}
+static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
+{
+ /* UDP-lite can't land here - no GRO */
+ WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov);
+
+ /* UDP packets generated with UDP_SEGMENT and traversing:
+ *
+ * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
+ *
+ * can reach an UDP socket with CHECKSUM_NONE, because
+ * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
+ * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
+ * have a valid checksum, as the GRO engine validates the UDP csum
+ * before the aggregation and nobody strips such info in between.
+ * Instead of adding another check in the tunnel fastpath, we can force
+ * a valid csum after the segmentation.
+ * Additionally fixup the UDP CB.
+ */
+ UDP_SKB_CB(skb)->cscov = skb->len;
+ if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
+ skb->csum_valid = 1;
+}
+
#ifdef CONFIG_BPF_SYSCALL
struct sk_psock;
struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 4a0478b17243..fe85dcf8c008 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2178,6 +2178,8 @@ static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
segs = udp_rcv_segment(sk, skb, true);
skb_list_walk_safe(segs, skb, next) {
__skb_pull(skb, skb_transport_offset(skb));
+
+ udp_post_segment_fix_csum(skb);
ret = udp_queue_rcv_one_skb(sk, skb);
if (ret > 0)
ip_protocol_deliver_rcu(dev_net(skb->dev), skb, ret);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index d25e5a9252fd..fa2f54738392 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -749,6 +749,7 @@ static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
skb_list_walk_safe(segs, skb, next) {
__skb_pull(skb, skb_transport_offset(skb));
+ udp_post_segment_fix_csum(skb);
ret = udpv6_queue_rcv_one_skb(sk, skb);
if (ret > 0)
ip6_protocol_deliver_rcu(dev_net(skb->dev), skb, ret,