cba7c76ea1
commit 2061ecfdf2350994e5b61c43e50e98a7a70e95ee upstream.
If packet headers changed, the cached nfct is no longer relevant
for the packet and attempt to re-use it leads to the incorrect packet
classification.
This issue is causing broken connectivity in OpenStack deployments
with OVS/OVN due to hairpin traffic being unexpectedly dropped.
The setup has datapath flows with several conntrack actions and tuple
changes between them:
actions:ct(commit,zone=8,mark=0/0x1,nat(src)),
set(eth(src=00:00:00:00:00:01,dst=00:00:00:00:00:06)),
set(ipv4(src=172.18.2.10,dst=192.168.100.6,ttl=62)),
ct(zone=8),recirc(0x4)
After the first ct() action the packet headers are almost fully
re-written. The next ct() tries to re-use the existing nfct entry
and marks the packet as invalid, so it gets dropped later in the
pipeline.
Clearing the cached conntrack entry whenever packet tuple is changed
to avoid the issue.
The flow key should not be cleared though, because we should still
be able to match on the ct_state if the recirculation happens after
the tuple change but before the next ct() action.
Cc: stable@vger.kernel.org
Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action")
Reported-by: Frode Nordahl <frode.nordahl@canonical.com>
Link: https://mail.openvswitch.org/pipermail/ovs-discuss/2022-May/051829.html
Link: https://bugs.launchpad.net/ubuntu/+source/ovn/+bug/1967856
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Link: https://lore.kernel.org/r/20220606221140.488984-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.