ipv4: igmp: guard against silly MTU values

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[ Upstream commit b5476022bb ]

IPv4 stack reacts to changes to small MTU, by disabling itself under
RTNL.

But there is a window where threads not using RTNL can see a wrong
device mtu. This can lead to surprises, in igmp code where it is
assumed the mtu is suitable.

Fix this by reading device mtu once and checking IPv4 minimal MTU.

This patch adds missing IPV4_MIN_MTU define, to not abuse
ETH_MIN_MTU anymore.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Eric Dumazet 2017-12-11 07:17:39 -08:00 • committed by Greg Kroah-Hartman

parent aa7f9011bc

commit 57dfc3d10e

4 changed files with 19 additions and 12 deletions

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include/net/ip.h

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