ipv6/exthdrs: accept tlv which includes only padding

[ Upstream commit 8112b1fe ]

In rfc4942 and rfc2460 I cannot find anything which would implicate to
drop packets which have only padding in tlv.

Current behaviour breaks TAHI Test v6LC.1.2.6.

Problem was intruduced in:
9b905fe6 "ipv6/exthdrs: strict Pad1 and PadN check"
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/ipv6/exthdrs.c

@@ -162,12 +162,6 @@ static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
 		off += optlen;
 		len -= optlen;
 	}
-	/* This case will not be caught by above check since its padding
-	 * length is smaller than 7:
-	 * 1 byte NH + 1 byte Length + 6 bytes Padding
-	 */
-	if ((padlen == 6) && ((off - skb_network_header_len(skb)) == 8))
-		goto bad;
 
 	if (len == 0)
 		return true;