[MCAST] IPv6: Check packet size when process Multicast

Signed-off-by: Yan Zheng <yanzheng@21cn.com
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index c4f2a0ef7489..966b2372aaab 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1087,7 +1087,7 @@ static void mld_marksources(struct ifmcaddr6 *pmc, int nsrcs,
 
 int igmp6_event_query(struct sk_buff *skb)
 {
-        struct mld2_query *mlh2 = (struct mld2_query *) skb->h.raw;
+        struct mld2_query *mlh2 = NULL;
         struct ifmcaddr6 *ma;
         struct in6_addr *group;
         unsigned long max_delay;
@@ -1140,6 +1140,13 @@ int igmp6_event_query(struct sk_buff *skb)
                 /* clear deleted report items */
                 mld_clear_delrec(idev);
         } else if (len >= 28) {
+                int srcs_offset = sizeof(struct mld2_query) - 
+                                  sizeof(struct icmp6hdr);
+                if (!pskb_may_pull(skb, srcs_offset)) {
+                        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;
@@ -1156,7 +1163,15 @@ int igmp6_event_query(struct sk_buff *skb)
                         return 0;
                 }
                 /* mark sources to include, if group & source-specific */
-                mark = mlh2->nsrcs != 0;
+                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;
+                }
         } else {
                 in6_dev_put(idev);
                 return -EINVAL;