With the newly introduced helper functions the skb pulling is hidden in the checksumming function - and undone before returning to the caller. The IGMPv3 and MLDv2 report parsing functions in the bridge still assumed that the skb is pointing to the beginning of the IGMP/MLD message while it is now kept at the beginning of the IPv4/6 header, breaking the message parsing and creating packet loss. Fixing this by taking the offset between IP and IGMP/MLD header into account, too. Fixes: 9afd85c9e455 ("net: Export IGMP/MLD message validation code") Reported-by: Tobias Powalowski <tobias.powalowski@xxxxxxxxxxxxxx> Tested-by: Tobias Powalowski <tobias.powalowski@xxxxxxxxxxxxxx> Signed-off-by: Linus Lüssing <linus.luessing@xxxxxxxxx> --- net/bridge/br_multicast.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 66efdc2..480b3de 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1006,7 +1006,7 @@ static int br_ip4_multicast_igmp3_report(struct net_bridge *br, ih = igmpv3_report_hdr(skb); num = ntohs(ih->ngrec); - len = sizeof(*ih); + len = skb_transport_offset(skb) + sizeof(*ih); for (i = 0; i < num; i++) { len += sizeof(*grec); @@ -1067,7 +1067,7 @@ static int br_ip6_multicast_mld2_report(struct net_bridge *br, icmp6h = icmp6_hdr(skb); num = ntohs(icmp6h->icmp6_dataun.un_data16[1]); - len = sizeof(*icmp6h); + len = skb_transport_offset(skb) + sizeof(*icmp6h); for (i = 0; i < num; i++) { __be16 *nsrcs, _nsrcs; -- 1.7.10.4