[PATCH 4.9 10/16] igmp: Fix regression caused by igmp sysctl namespace code.

Greg Kroah-Hartman
2017-08-11T22:13:51Z

From: Nikolay Borisov <nborisov@suse.com>

[ Upstream commit 1714020e42b17135032c8606f7185b3fb2ba5d78 ]

Commit dcd87999d415 ("igmp: net: Move igmp namespace init to correct file")
moved the igmp sysctls initialization from tcp_sk_init to igmp_net_init. This
function is only called as part of per-namespace initialization, only if
CONFIG_IP_MULTICAST is defined, otherwise igmp_mc_init() call in ip_init is
compiled out, casuing the igmp pernet ops to not be registerd and those sysctl
being left initialized with 0. However, there are certain functions, such as
ip_mc_join_group which are always compiled and make use of some of those
sysctls. Let's do a partial revert of the aforementioned commit and move the
sysctl initialization into inet_init_net, that way they will always have
sane values.

Fixes: dcd87999d415 ("igmp: net: Move igmp namespace init to correct file")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196595
Reported-by: Gerardo Exequiel Pozzi <vmlinuz386@gmail.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/af_inet.c | 7 +++++++
net/ipv4/igmp.c | 6 ------
2 files changed, 7 insertions(+), 6 deletions(-)

--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1693,6 +1693,13 @@ static __net_init int inet_init_net(stru
net->ipv4.sysctl_ip_dynaddr = 0;
net->ipv4.sysctl_ip_early_demux = 1;

+ /* Some igmp sysctl, whose values are always used */
+ net->ipv4.sysctl_igmp_max_memberships = 20;
+ net->ipv4.sysctl_igmp_max_msf = 10;
+ /* IGMP reports for link-local multicast groups are enabled by default */
+ net->ipv4.sysctl_igmp_llm_reports = 1;
+ net->ipv4.sysctl_igmp_qrv = 2;
+
return 0;
}

--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -2974,12 +2974,6 @@ static int __net_init igmp_net_init(stru
goto out_sock;
}

- /* Sysctl initialization */
- net->ipv4.sysctl_igmp_max_memberships = 20;
- net->ipv4.sysctl_igmp_max_msf = 10;
- /* IGMP reports for link-local multicast groups are enabled by default */
- net->ipv4.sysctl_igmp_llm_reports = 1;
- net->ipv4.sysctl_igmp_qrv = 2;
return 0;