net: igmp: fix source address check for IGMPv3 reports
authorFelix Fietkau <nbd@nbd.name>
Fri, 19 Jan 2018 10:50:46 +0000 (11:50 +0100)
committerBen Hutchings <ben@decadent.org.uk>
Sat, 3 Mar 2018 15:51:02 +0000 (15:51 +0000)
commit ad23b750933ea7bf962678972a286c78a8fa36aa upstream.

Commit "net: igmp: Use correct source address on IGMPv3 reports"
introduced a check to validate the source address of locally generated
IGMPv3 packets.
Instead of checking the local interface address directly, it uses
inet_ifa_match(fl4->saddr, ifa), which checks if the address is on the
local subnet (or equal to the point-to-point address if used).

This breaks for point-to-point interfaces, so check against
ifa->ifa_local directly.

Cc: Kevin Cernekee <cernekee@chromium.org>
Fixes: a46182b00290 ("net: igmp: Use correct source address on IGMPv3 reports")
Reported-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
net/ipv4/igmp.c

index e80cd5a..96ad44a 100644 (file)
@@ -310,7 +310,7 @@ static __be32 igmpv3_get_srcaddr(struct net_device *dev,
                return htonl(INADDR_ANY);
 
        for_ifa(in_dev) {
                return htonl(INADDR_ANY);
 
        for_ifa(in_dev) {
-               if (inet_ifa_match(fl4->saddr, ifa))
+               if (fl4->saddr == ifa->ifa_local)
                        return fl4->saddr;
        } endfor_ifa(in_dev);
 
                        return fl4->saddr;
        } endfor_ifa(in_dev);