From 5fc6266af7b427243da24f3443a50cd4584aac06 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Linus=20L=C3=BCssing?= Date: Sun, 5 Jul 2020 21:10:17 +0200 Subject: [PATCH] bridge: mcast: Fix MLD2 Report IPv6 payload length check MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit e57f61858b7c ("net: bridge: mcast: fix stale nsrcs pointer in igmp3/mld2 report handling") introduced a bug in the IPv6 header payload length check which would potentially lead to rejecting a valid MLD2 Report: The check needs to take into account the 2 bytes for the "Number of Sources" field in the "Multicast Address Record" before reading it. And not the size of a pointer to this field. Fixes: e57f61858b7c ("net: bridge: mcast: fix stale nsrcs pointer in igmp3/mld2 report handling") Acked-by: Nikolay Aleksandrov Signed-off-by: Linus Lüssing Signed-off-by: David S. Miller --- net/bridge/br_multicast.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 83490bf73a13..4c4a93abde68 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1007,7 +1007,7 @@ static int br_ip6_multicast_mld2_report(struct net_bridge *br, nsrcs_offset = len + offsetof(struct mld2_grec, grec_nsrcs); if (skb_transport_offset(skb) + ipv6_transport_len(skb) < - nsrcs_offset + sizeof(_nsrcs)) + nsrcs_offset + sizeof(__nsrcs)) return -EINVAL; _nsrcs = skb_header_pointer(skb, nsrcs_offset,