espintcp: fix skb leaks

A few error paths are missing a kfree_skb.

Fixes: e27cca9 ("xfrm: add espintcp (RFC 8229)")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Author: qsn

net/ipv4/esp4.c

@@ -199,8 +199,10 @@ static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
 
 	sk = esp_find_tcp_sk(x);
 	err = PTR_ERR_OR_ZERO(sk);
-	if (err)
+	if (err) {
+		kfree_skb(skb);
 		goto out;
+	}
 
 	bh_lock_sock(sk);
 	if (sock_owned_by_user(sk))

net/ipv6/esp6.c

@@ -216,8 +216,10 @@ static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
 
 	sk = esp6_find_tcp_sk(x);
 	err = PTR_ERR_OR_ZERO(sk);
-	if (err)
+	if (err) {
+		kfree_skb(skb);
 		goto out;
+	}
 
 	bh_lock_sock(sk);
 	if (sock_owned_by_user(sk))

net/xfrm/espintcp.c

@@ -171,8 +171,10 @@ int espintcp_queue_out(struct sock *sk, struct sk_buff *skb)
 	struct espintcp_ctx *ctx = espintcp_getctx(sk);
 
 	if (skb_queue_len(&ctx->out_queue) >=
-	    READ_ONCE(net_hotdata.max_backlog))
+	    READ_ONCE(net_hotdata.max_backlog)) {
+		kfree_skb(skb);
 		return -ENOBUFS;
+	}
 
 	__skb_queue_tail(&ctx->out_queue, skb);