WSL2-Linux-Kernel/net/openvswitch
Rosemarie O'Riorden cbf5852695 net: openvswitch: fix parsing of nw_proto for IPv6 fragments
commit 12378a5a75 upstream.

When a packet enters the OVS datapath and does not match any existing
flows installed in the kernel flow cache, the packet will be sent to
userspace to be parsed, and a new flow will be created. The kernel and
OVS rely on each other to parse packet fields in the same way so that
packets will be handled properly.

As per the design document linked below, OVS expects all later IPv6
fragments to have nw_proto=44 in the flow key, so they can be correctly
matched on OpenFlow rules. OpenFlow controllers create pipelines based
on this design.

This behavior was changed by the commit in the Fixes tag so that
nw_proto equals the next_header field of the last extension header.
However, there is no counterpart for this change in OVS userspace,
meaning that this field is parsed differently between OVS and the
kernel. This is a problem because OVS creates actions based on what is
parsed in userspace, but the kernel-provided flow key is used as a match
criteria, as described in Documentation/networking/openvswitch.rst. This
leads to issues such as packets incorrectly matching on a flow and thus
the wrong list of actions being applied to the packet. Such changes in
packet parsing cannot be implemented without breaking the userspace.

The offending commit is partially reverted to restore the expected
behavior.

The change technically made sense and there is a good reason that it was
implemented, but it does not comply with the original design of OVS.
If in the future someone wants to implement such a change, then it must
be user-configurable and disabled by default to preserve backwards
compatibility with existing OVS versions.

Cc: stable@vger.kernel.org
Fixes: fa642f0883 ("openvswitch: Derive IP protocol number for IPv6 later frags")
Link: https://docs.openvswitch.org/en/latest/topics/design/#fragments
Signed-off-by: Rosemarie O'Riorden <roriorden@redhat.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Link: https://lore.kernel.org/r/20220621204845.9721-1-roriorden@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-29 09:03:18 +02:00
..
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile openvswitch: add trace points 2021-06-22 10:47:32 -07:00
actions.c net: openvswitch: fix misuse of the cached connection on tuple changes 2022-06-14 18:36:26 +02:00
conntrack.c net: openvswitch: fix misuse of the cached connection on tuple changes 2022-06-14 18:36:26 +02:00
conntrack.h net/sched: act_api: fix miss set post_ct for ovs after do conntrack in act_ct 2021-03-16 15:22:18 -07:00
datapath.c openvswitch: fix sparse warning incorrect type 2021-07-27 11:48:43 +01:00
datapath.h openvswitch: Introduce per-cpu upcall dispatch 2021-07-16 11:06:33 -07:00
dp_notify.c net: openvswitch: use netif_ovs_is_port() instead of opencode 2019-07-08 15:53:25 -07:00
flow.c net: openvswitch: fix parsing of nw_proto for IPv6 fragments 2022-06-29 09:03:18 +02:00
flow.h treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
flow_netlink.c openvswitch: fix OOB access in reserve_sfa_size() 2022-04-27 14:39:00 +02:00
flow_netlink.h
flow_table.c openvswitch: Optimize operation for key comparison 2021-07-01 11:13:10 -07:00
flow_table.h net: openvswitch: fix to make sure flow_lookup() is not preempted 2020-10-18 12:29:36 -07:00
meter.c openvswitch: meter: fix race when getting now_ms. 2021-05-13 15:54:59 -07:00
meter.h net: openvswitch: use u64 for meter bucket 2020-04-23 18:26:11 -07:00
openvswitch_trace.c openvswitch: add trace points 2021-06-22 10:47:32 -07:00
openvswitch_trace.h openvswitch: add trace points 2021-06-22 10:47:32 -07:00
vport-geneve.c
vport-gre.c
vport-internal_dev.c net: openvswitch: use core API to update/provide stats 2020-11-14 16:59:32 -08:00
vport-internal_dev.h
vport-netdev.c net: openvswitch: Use 'skb_push_rcsum()' instead of hand coding it 2021-04-04 01:43:02 -07:00
vport-netdev.h
vport-vxlan.c
vport.c ovs: clear skb->tstamp in forwarding path 2021-08-18 11:31:13 +01:00
vport.h openvswitch: Fix a typo 2021-03-22 12:59:46 -07:00