From: "Linus L�ssing" linus.luessing@c0d3.blue
[ Upstream commit 5fc6266af7b427243da24f3443a50cd4584aac06 ]
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 nikolay@cumulusnetworks.com Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/bridge/br_multicast.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1007,7 +1007,7 @@ static int br_ip6_multicast_mld2_report( 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,