Open vSwitch module accepts actions as a list from the netlink socket and then creates a copy which it uses in the action set processing. During processing of the action list on a packet, the module keeps a count of the execution depth and exits processing if the action depth goes too high.
However, during netlink processing the recursion depth isn't checked anywhere, and the copy trusts that kernel has large enough stack to accommodate it. The OVS sample action was the original action which could perform this kinds of recursion, and it originally checked that it didn't exceed the sample depth limit. However, when sample became optimized to provide the clone() semantics, the recursion limit was dropped. This series adds a depth limit during the __ovs_nla_copy_actions() call that will ensure we don't exceed the max that the OVS userspace could generate for a clone(). Additionally, this series provides a selftest in 2/2 that can be used to determine if the OVS module is allowing unbounded access. It can be safely omitted where the ovs selftest framework isn't available. Aaron Conole (2): net: openvswitch: limit the number of recursions from action sets selftests: openvswitch: Add validation for the recursion test net/openvswitch/flow_netlink.c | 33 +++++++-- .../selftests/net/openvswitch/openvswitch.sh | 13 ++++ .../selftests/net/openvswitch/ovs-dpctl.py | 71 +++++++++++++++---- 3 files changed, 97 insertions(+), 20 deletions(-) -- 2.41.0 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
