net: ipv6: mld: similarly to MLDv2 have min max_delay of 1

Similarly as we do in MLDv2 queries, set a forged MLDv1 query with
0 ms mld_maxdelay to minimum timer shot time of 1 jiffies. This is
eventually done in igmp6_group_queried() anyway, so we can simplify
a check there.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index c916568d838aad2286258be226f51a18cf166136..beb76b7989a7c75f1b151d68f05b5be3b4ed1853 100644 (file)
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1040,12 +1040,9 @@ static void igmp6_group_queried(struct ifmcaddr6 *ma, unsigned long resptime)
                delay = ma->mca_timer.expires - jiffies;
        }
 
-       if (delay >= resptime) {
-               if (resptime)
-                       delay = net_random() % resptime;
-               else
-                       delay = 1;
-       }
+       if (delay >= resptime)
+               delay = net_random() % resptime;
+
        ma->mca_timer.expires = jiffies + delay;
        if (!mod_timer(&ma->mca_timer, jiffies + delay))
                atomic_inc(&ma->mca_refcnt);
@@ -1258,12 +1255,15 @@ int igmp6_event_query(struct sk_buff *skb)
                return -EINVAL;
 
        if (len == MLD_V1_QUERY_LEN) {
+               unsigned long mldv1_md;
+
                /* Ignore v1 queries */
                if (mld_in_v2_mode_only(idev))
                        return 0;
 
                /* MLDv1 router present */
-               max_delay = msecs_to_jiffies(ntohs(mld->mld_maxdelay));
+               mldv1_md = ntohs(mld->mld_maxdelay);
+               max_delay = max(msecs_to_jiffies(mldv1_md), 1UL);
 
                mld_set_v1_mode(idev);