ipv6: fix possible mem leaks in ipv6_make_skb()

[ Upstream commit 862c03ee1deb7e19e0f9931682e0294ecd1fcaf9 ]

ip6_setup_cork() might return an error, while memory allocations have
been done and must be rolled back.

Fixes: 6422398c2ab0 ("ipv6: introduce ipv6_make_skb")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Reported-by: Mike Maloney <maloney@google.com>
Acked-by:  Mike Maloney <maloney@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index d0eed64..1f653f4 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1780,8 +1780,10 @@
 	cork.base.dst = NULL;
 	v6_cork.opt = NULL;
 	err = ip6_setup_cork(sk, &cork, &v6_cork, hlimit, tclass, opt, rt, fl6);
-	if (err)
+	if (err) {
+		ip6_cork_release(&cork, &v6_cork);
 		return ERR_PTR(err);
+	}
 	if (dontfrag < 0)
 		dontfrag = inet6_sk(sk)->dontfrag;