From 856ce5d083e14571d051301fe3c65b32b8cbe321 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Linus=20L=C3=BCssing?= Date: Wed, 4 May 2016 17:25:02 +0200 Subject: [PATCH] bridge: fix igmp / mld query parsing MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit With the newly introduced helper functions the skb pulling is hidden in the checksumming function - and undone before returning to the caller. The IGMP and MLD query 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. If there is a querier somewhere else, then this either causes the multicast snooping to stay disabled even though it could be enabled. Or, if we have the querier enabled too, then this can create unnecessary IGMP / MLD query messages on the link. 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: Simon Wunderlich Signed-off-by: Linus Lüssing Signed-off-by: David S. Miller --- net/bridge/br_multicast.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 191ea66e4d92..6852f3c7009c 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1279,6 +1279,7 @@ static int br_ip4_multicast_query(struct net_bridge *br, struct br_ip saddr; unsigned long max_delay; unsigned long now = jiffies; + unsigned int offset = skb_transport_offset(skb); __be32 group; int err = 0; @@ -1289,14 +1290,14 @@ static int br_ip4_multicast_query(struct net_bridge *br, group = ih->group; - if (skb->len == sizeof(*ih)) { + if (skb->len == offset + sizeof(*ih)) { max_delay = ih->code * (HZ / IGMP_TIMER_SCALE); if (!max_delay) { max_delay = 10 * HZ; group = 0; } - } else if (skb->len >= sizeof(*ih3)) { + } else if (skb->len >= offset + sizeof(*ih3)) { ih3 = igmpv3_query_hdr(skb); if (ih3->nsrcs) goto out; @@ -1357,6 +1358,7 @@ static int br_ip6_multicast_query(struct net_bridge *br, struct br_ip saddr; unsigned long max_delay; unsigned long now = jiffies; + unsigned int offset = skb_transport_offset(skb); const struct in6_addr *group = NULL; bool is_general_query; int err = 0; @@ -1366,8 +1368,8 @@ static int br_ip6_multicast_query(struct net_bridge *br, (port && port->state == BR_STATE_DISABLED)) goto out; - if (skb->len == sizeof(*mld)) { - if (!pskb_may_pull(skb, sizeof(*mld))) { + if (skb->len == offset + sizeof(*mld)) { + if (!pskb_may_pull(skb, offset + sizeof(*mld))) { err = -EINVAL; goto out; } @@ -1376,7 +1378,7 @@ static int br_ip6_multicast_query(struct net_bridge *br, if (max_delay) group = &mld->mld_mca; } else { - if (!pskb_may_pull(skb, sizeof(*mld2q))) { + if (!pskb_may_pull(skb, offset + sizeof(*mld2q))) { err = -EINVAL; goto out; } -- 2.20.1