3 files changed, 53 insertions, 6 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b8b06e71b73e..14b923ddb6df 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3033,6 +3033,29 @@ static inline void skb_reset_transport_header(struct sk_buff *skb)
 	skb->transport_header = offset;
 }
 
+/**
+ * skb_reset_transport_header_careful - conditionally reset transport header
+ * @skb: buffer to alter
+ *
+ * Hardened version of skb_reset_transport_header().
+ *
+ * Returns: true if the operation was a success.
+ */
+static inline bool __must_check
+skb_reset_transport_header_careful(struct sk_buff *skb)
+{
+	long offset = skb->data - skb->head;
+
+	if (unlikely(offset != (typeof(skb->transport_header))offset))
+		return false;
+
+	if (unlikely(offset == (typeof(skb->transport_header))~0U))
+		return false;
+
+	skb->transport_header = offset;
+	return true;
+}
+
 static inline void skb_set_transport_header(struct sk_buff *skb,
 					    const int offset)
 {
diff --git a/include/net/dst.h b/include/net/dst.h
index 00467c1b5093..bab01363bb97 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -568,11 +568,23 @@ static inline struct net_device *dst_dev(const struct dst_entry *dst)
 	return READ_ONCE(dst->dev);
 }
 
+static inline struct net_device *dst_dev_rcu(const struct dst_entry *dst)
+{
+	/* In the future, use rcu_dereference(dst->dev) */
+	WARN_ON_ONCE(!rcu_read_lock_held());
+	return READ_ONCE(dst->dev);
+}
+
 static inline struct net_device *skb_dst_dev(const struct sk_buff *skb)
 {
 	return dst_dev(skb_dst(skb));
 }
 
+static inline struct net_device *skb_dst_dev_rcu(const struct sk_buff *skb)
+{
+	return dst_dev_rcu(skb_dst(skb));
+}
+
 static inline struct net *skb_dst_dev_net(const struct sk_buff *skb)
 {
 	return dev_net(skb_dst_dev(skb));
diff --git a/include/net/udp.h b/include/net/udp.h
index f8ae2c4ade14..e2af3bda90c9 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -586,6 +586,16 @@ static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
 {
 	netdev_features_t features = NETIF_F_SG;
 	struct sk_buff *segs;
+	int drop_count;
+
+	/*
+	 * Segmentation in UDP receive path is only for UDP GRO, drop udp
+	 * fragmentation offload (UFO) packets.
+	 */
+	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) {
+		drop_count = 1;
+		goto drop;
+	}
 
 	/* Avoid csum recalculation by skb_segment unless userspace explicitly
 	 * asks for the final checksum values
@@ -609,16 +619,18 @@ static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
 	 */
 	segs = __skb_gso_segment(skb, features, false);
 	if (IS_ERR_OR_NULL(segs)) {
-		int segs_nr = skb_shinfo(skb)->gso_segs;
-
-		atomic_add(segs_nr, &sk->sk_drops);
-		SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
-		kfree_skb(skb);
-		return NULL;
+		drop_count = skb_shinfo(skb)->gso_segs;
+		goto drop;
 	}
 
 	consume_skb(skb);
 	return segs;
+
+drop:
+	atomic_add(drop_count, &sk->sk_drops);
+	SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, drop_count);
+	kfree_skb(skb);
+	return NULL;
 }
 
 static inline void udp_post_segment_fix_csum(struct sk_buff *skb)