Check packet size when process Multicast Address and Source Specific Query

The patch changes the old one to equivalent code in IGMPv3 as David Stevens's suggestion
http://lkml.org/lkml/2005/10/31/221

Regards

Index:net/ipv6/mcast.c
==============================================================

@@ -1149,6 +1149,14 @@ int igmp6_event_query(struct sk_buff *sk

			return -EINVAL;
		}
		mlh2 = (struct mld2_query *) skb->h.raw;

+ if (mlh2->nsrcs != 0) {
+ if (!pskb_may_pull(skb, srcs_offset +
+ mlh2->nsrcs * sizeof(struct in6_addr))) {
+ in6_dev_put(idev);
+ return -EINVAL;
+ }
+ mlh2 = (struct mld2_query *) skb->h.raw;
+ }

		max_delay = (MLDV2_MRC(ntohs(mlh2->mrc))*HZ)/1000;
		if (!max_delay)
			max_delay = 1;
@@ -1165,15 +1173,7 @@ int igmp6_event_query(struct sk_buff *sk
			return 0;
		}
		/* mark sources to include, if group & source-specific */

- if (mlh2->nsrcs != 0) {
- if (!pskb_may_pull(skb, srcs_offset + - mlh2->nsrcs * sizeof(struct in6_addr))) {
- in6_dev_put(idev);
- return -EINVAL;
- }
- mlh2 = (struct mld2_query *) skb->h.raw;
- mark = 1;
- }

+		mark = mlh2->nsrcs != 0;
	} else {
		in6_dev_put(idev);
		return -EINVAL;