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| author | David Stevens <dlstevens@us.ibm.com> | 2005-12-02 20:32:59 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-12-02 20:32:59 -0800 |
| commit | 24c6927505ca77ee4ac25fb31dcd56f6506979ed (patch) | |
| tree | 17d873b63f0ce24b81e184f2515f2b643143e48e /net/ipv4/igmp.c | |
| parent | bf031fff1fac77775b2cd2c72ad8b017f4c0af13 (diff) | |
| download | lwn-24c6927505ca77ee4ac25fb31dcd56f6506979ed.tar.gz lwn-24c6927505ca77ee4ac25fb31dcd56f6506979ed.zip | |
[IGMP]: workaround for IGMP v1/v2 bug
From: David Stevens <dlstevens@us.ibm.com>
As explained at:
http://www.cs.ucsb.edu/~krishna/igmp_dos/
With IGMP version 1 and 2 it is possible to inject a unicast
report to a client which will make it ignore multicast
reports sent later by the router.
The fix is to only accept the report if is was sent to a
multicast or unicast address.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/igmp.c')
| -rw-r--r-- | net/ipv4/igmp.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index c04607b49212..4a195c724f01 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -897,7 +897,10 @@ int igmp_rcv(struct sk_buff *skb) /* Is it our report looped back? */ if (((struct rtable*)skb->dst)->fl.iif == 0) break; - igmp_heard_report(in_dev, ih->group); + /* don't rely on MC router hearing unicast reports */ + if (skb->pkt_type == PACKET_MULTICAST || + skb->pkt_type == PACKET_BROADCAST) + igmp_heard_report(in_dev, ih->group); break; case IGMP_PIM: #ifdef CONFIG_IP_PIMSM_V1 |