xfrm6: fix the proto and ports decode of sctp protocol
xfrm6: fix the proto and ports decode of sctp protocol

The SCTP pushed the skb above the sctp chunk header, so the
check of pskb_may_pull(skb, nh + offset + 1 - skb->data) in
_decode_session6() will never return 0 and the ports decode
of sctp will always fail. (nh + offset + 1 - skb->data < 0)

Signed-off-by: Wei Yongjun <f52b9831d10c067ffbc33238e89e1e27651b0884@cn.fujitsu.com>
Acked-by: Herbert Xu <ef65de1c7be0aa837fe7b25ba9a7739905af6a55@gondor.apana.org.au>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs