4 files changed, 17 insertions, 12 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index 327ca73f9cd7..7a72f766aacf 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3233,6 +3233,13 @@ static const struct bpf_func_proto bpf_skb_vlan_pop_proto = {
 	.arg1_type      = ARG_PTR_TO_CTX,
 };
 
+static void bpf_skb_change_protocol(struct sk_buff *skb, u16 proto)
+{
+	skb->protocol = htons(proto);
+	if (skb_valid_dst(skb))
+		skb_dst_drop(skb);
+}
+
 static int bpf_skb_generic_push(struct sk_buff *skb, u32 off, u32 len)
 {
 	/* Caller already did skb_cow() with len as headroom,
@@ -3329,7 +3336,7 @@ static int bpf_skb_proto_4_to_6(struct sk_buff *skb)
 		}
 	}
 
-	skb->protocol = htons(ETH_P_IPV6);
+	bpf_skb_change_protocol(skb, ETH_P_IPV6);
 	skb_clear_hash(skb);
 
 	return 0;
@@ -3359,7 +3366,7 @@ static int bpf_skb_proto_6_to_4(struct sk_buff *skb)
 		}
 	}
 
-	skb->protocol = htons(ETH_P_IP);
+	bpf_skb_change_protocol(skb, ETH_P_IP);
 	skb_clear_hash(skb);
 
 	return 0;
@@ -3550,10 +3557,10 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff,
 		/* Match skb->protocol to new outer l3 protocol */
 		if (skb->protocol == htons(ETH_P_IP) &&
 		    flags & BPF_F_ADJ_ROOM_ENCAP_L3_IPV6)
-			skb->protocol = htons(ETH_P_IPV6);
+			bpf_skb_change_protocol(skb, ETH_P_IPV6);
 		else if (skb->protocol == htons(ETH_P_IPV6) &&
 			 flags & BPF_F_ADJ_ROOM_ENCAP_L3_IPV4)
-			skb->protocol = htons(ETH_P_IP);
+			bpf_skb_change_protocol(skb, ETH_P_IP);
 	}
 
 	if (skb_is_gso(skb)) {
@@ -3606,10 +3613,10 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff,
 	/* Match skb->protocol to new outer l3 protocol */
 	if (skb->protocol == htons(ETH_P_IP) &&
 	    flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV6)
-		skb->protocol = htons(ETH_P_IPV6);
+		bpf_skb_change_protocol(skb, ETH_P_IPV6);
 	else if (skb->protocol == htons(ETH_P_IPV6) &&
 		 flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV4)
-		skb->protocol = htons(ETH_P_IP);
+		bpf_skb_change_protocol(skb, ETH_P_IP);
 
 	if (skb_is_gso(skb)) {
 		struct skb_shared_info *shinfo = skb_shinfo(skb);
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 4ddb7490df4b..6ad84d4a2b46 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -432,6 +432,7 @@ int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 	udph->dest = htons(np->remote_port);
 	udph->len = htons(udp_len);
 
+	udph->check = 0;
 	if (np->ipv6) {
 		udph->check = csum_ipv6_magic(&np->local_ip.in6,
 					      &np->remote_ip.in6,
@@ -460,7 +461,6 @@ int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 		skb_reset_mac_header(skb);
 		skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 	} else {
-		udph->check = 0;
 		udph->check = csum_tcpudp_magic(np->local_ip.ip,
 						np->remote_ip.ip,
 						udp_len, IPPROTO_UDP,
diff --git a/net/core/selftests.c b/net/core/selftests.c
index 35f807ea9952..406faf8e5f3f 100644
--- a/net/core/selftests.c
+++ b/net/core/selftests.c
@@ -160,8 +160,9 @@ static struct sk_buff *net_test_get_skb(struct net_device *ndev,
 	skb->csum = 0;
 	skb->ip_summed = CHECKSUM_PARTIAL;
 	if (attr->tcp) {
-		thdr->check = ~tcp_v4_check(skb->len, ihdr->saddr,
-					    ihdr->daddr, 0);
+		int l4len = skb->len - skb_transport_offset(skb);
+
+		thdr->check = ~tcp_v4_check(l4len, ihdr->saddr, ihdr->daddr, 0);
 		skb->csum_start = skb_transport_header(skb) - skb->head;
 		skb->csum_offset = offsetof(struct tcphdr, check);
 	} else {
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 85fc82f72d26..d6420b74ea9c 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -6261,9 +6261,6 @@ int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len)
 	if (!pskb_may_pull(skb, write_len))
 		return -ENOMEM;
 
-	if (!skb_frags_readable(skb))
-		return -EFAULT;
-
 	if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
 		return 0;