openvswitch: Delete conntrack entry clashing with an expectation.
[ Upstream commit cf5d7091 ] Conntrack helpers do not check for a potentially clashing conntrack entry when creating a new expectation. Also, nf_conntrack_in() will check expectations (via init_conntrack()) only if a conntrack entry can not be found. The expectation for a packet which also matches an existing conntrack entry will not be removed by conntrack, and is currently handled inconsistently by OVS, as OVS expects the expectation to be removed when the connection tracking entry matching that expectation is confirmed. It should be noted that normally an IP stack would not allow reuse of a 5-tuple of an old (possibly lingering) connection for a new data connection, so this is somewhat unlikely corner case. However, it is possible that a misbehaving source could cause conntrack entries be created that could then interfere with new related connections. Fix this in the OVS module by deleting the clashing conntrack entry after an expectation has been matched. This causes the following nf_conntrack_in() call also find the expectation and remove it when creating the new conntrack entry, as well as the forthcoming reply direction packets to match the new related connection instead of the old clashing conntrack entry. Fixes: 7f8a436e ("openvswitch: Add conntrack action") Reported-by: Yang Song <yangsong@vmware.com> Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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