netfilter: nft_socket: fix sk refcount leaks

We must put 'sk' reference before returning.

Fixes: 039b1f4f ("netfilter: nft_socket: fix erroneous socket assignment")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_socket.c

@@ -110,13 +110,13 @@ static void nft_socket_eval(const struct nft_expr *expr,
 			*dest = READ_ONCE(sk->sk_mark);
 		} else {
 			regs->verdict.code = NFT_BREAK;
-			return;
+			goto out_put_sk;
 		}
 		break;
 	case NFT_SOCKET_WILDCARD:
 		if (!sk_fullsock(sk)) {
 			regs->verdict.code = NFT_BREAK;
-			return;
+			goto out_put_sk;
 		}
 		nft_socket_wildcard(pkt, regs, sk, dest);
 		break;
@@ -124,7 +124,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
 	case NFT_SOCKET_CGROUPV2:
 		if (!nft_sock_get_eval_cgroupv2(dest, sk, pkt, priv->level)) {
 			regs->verdict.code = NFT_BREAK;
-			return;
+			goto out_put_sk;
 		}
 		break;
 #endif
@@ -133,6 +133,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
 		regs->verdict.code = NFT_BREAK;
 	}
 
+out_put_sk:
 	if (sk != skb->sk)
 		sock_gen_put(sk);
 }