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    SubjectRe: [PATCH 4.9 27/75] net: igmp: Use correct source address on IGMPv3 reports
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    3.18 and 4.4 is affected too

    Am 16.01.2018 um 04:50 schrieb Sebastian Gottschall:
    > please revert that on 4.9 and 4.14
    > it breaks igmp routing. it can be reproduced with any iptv connection
    > using igmp-proxy. reverting this patch fixes the issue.
    >
    > Sebastian
    >
    >
    >
    > Am 01.01.2018 um 15:32 schrieb Greg Kroah-Hartman:
    >> 4.9-stable review patch.  If anyone has any objections, please let me
    >> know.
    >>
    >> ------------------
    >>
    >> From: Kevin Cernekee <cernekee@chromium.org>
    >>
    >>
    >> [ Upstream commit a46182b00290839fa3fa159d54fd3237bd8669f0 ]
    >>
    >> Closing a multicast socket after the final IPv4 address is deleted
    >> from an interface can generate a membership report that uses the
    >> source IP from a different interface.  The following test script, run
    >> from an isolated netns, reproduces the issue:
    >>
    >>      #!/bin/bash
    >>
    >>      ip link add dummy0 type dummy
    >>      ip link add dummy1 type dummy
    >>      ip link set dummy0 up
    >>      ip link set dummy1 up
    >>      ip addr add 10.1.1.1/24 dev dummy0
    >>      ip addr add 192.168.99.99/24 dev dummy1
    >>
    >>      tcpdump -U -i dummy0 &
    >>      socat EXEC:"sleep 2" \
    >> UDP4-DATAGRAM:239.101.1.68:8889,ip-add-membership=239.0.1.68:10.1.1.1 &
    >>
    >>      sleep 1
    >>      ip addr del 10.1.1.1/24 dev dummy0
    >>      sleep 5
    >>      kill %tcpdump
    >>
    >> RFC 3376 specifies that the report must be sent with a valid IP source
    >> address from the destination subnet, or from address 0.0.0.0. Add an
    >> extra check to make sure this is the case.
    >>
    >> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
    >> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
    >> Signed-off-by: David S. Miller <davem@davemloft.net>
    >> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    >> ---
    >>   net/ipv4/igmp.c |   20 +++++++++++++++++++-
    >>   1 file changed, 19 insertions(+), 1 deletion(-)
    >>
    >> --- a/net/ipv4/igmp.c
    >> +++ b/net/ipv4/igmp.c
    >> @@ -89,6 +89,7 @@
    >>   #include <linux/rtnetlink.h>
    >>   #include <linux/times.h>
    >>   #include <linux/pkt_sched.h>
    >> +#include <linux/byteorder/generic.h>
    >>     #include <net/net_namespace.h>
    >>   #include <net/arp.h>
    >> @@ -321,6 +322,23 @@ igmp_scount(struct ip_mc_list *pmc, int
    >>       return scount;
    >>   }
    >>   +/* source address selection per RFC 3376 section 4.2.13 */
    >> +static __be32 igmpv3_get_srcaddr(struct net_device *dev,
    >> +                 const struct flowi4 *fl4)
    >> +{
    >> +    struct in_device *in_dev = __in_dev_get_rcu(dev);
    >> +
    >> +    if (!in_dev)
    >> +        return htonl(INADDR_ANY);
    >> +
    >> +    for_ifa(in_dev) {
    >> +        if (inet_ifa_match(fl4->saddr, ifa))
    >> +            return fl4->saddr;
    >> +    } endfor_ifa(in_dev);
    >> +
    >> +    return htonl(INADDR_ANY);
    >> +}
    >> +
    >>   static struct sk_buff *igmpv3_newpack(struct net_device *dev,
    >> unsigned int mtu)
    >>   {
    >>       struct sk_buff *skb;
    >> @@ -368,7 +386,7 @@ static struct sk_buff *igmpv3_newpack(st
    >>       pip->frag_off = htons(IP_DF);
    >>       pip->ttl      = 1;
    >>       pip->daddr    = fl4.daddr;
    >> -    pip->saddr    = fl4.saddr;
    >> +    pip->saddr    = igmpv3_get_srcaddr(dev, &fl4);
    >>       pip->protocol = IPPROTO_IGMP;
    >>       pip->tot_len  = 0;    /* filled in later */
    >>       ip_select_ident(net, skb, NULL);
    >>
    >>
    >>
    >

    --
    Mit freundlichen Grüssen / Regards

    Sebastian Gottschall / CTO

    NewMedia-NET GmbH - DD-WRT
    Firmensitz: Stubenwaldallee 21a, 64625 Bensheim
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    http://www.dd-wrt.com
    email: s.gottschall@dd-wrt.com
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