tree f4cbdf604f01fcd3c0bd25fe819aaa0cf8825b40
parent 60a6531bfe49555581ccd65f66a350cc5693fcde
author Hannes Frederic Sowa <hannes@stressinduktion.org> 1453136628 +0100
committer David S. Miller <davem@davemloft.net> 1453136985 -0500

ovs: limit ovs recursions in ovs_execute_actions to not corrupt stack

It was seen that defective configurations of openvswitch could overwrite
the STACK_END_MAGIC and cause a hard crash of the kernel because of too
many recursions within ovs.

This problem arises due to the high stack usage of openvswitch. The rest
of the kernel is fine with the current limit of 10 (RECURSION_LIMIT).

We use the already existing recursion counter in ovs_execute_actions to
implement an upper bound of 5 recursions.

Cc: Pravin Shelar <pshelar@ovn.org>
Cc: Simon Horman <simon.horman@netronome.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>