The SA ID (src, dst, proto, spi) is unique on ingress.
As such, explicit inbound marking is not needed to match an SA.
On the other hand, requiring inbound SAs to use marks forces the
installation of a mechanism for marking traffic (e.g. iptables) based
on some criteria.
Defining the criteria becomes complicated, for example when required to
support multiple SAs from the same src, especially when traffic is UDP
encapsulated.
This commit removes the assignment of the child_sa mark_in to the inbound SA.
Policies can be arbitrated by existing means - e.g, via netfilter policy
matching or using VTI interfaces - without the need to classify the flows prior
to state matching.
Since the reqid allocator regards the mark value, there is no risk of matching
the wrong policy.
And as explicit marking was required for route-based VPN to work before this
change, it should not cause regressions in existing setups.
Closesstrongswan/strongswan#59.
If this is the first message by the peer, i.e. we expect MID 0, the
message is not pre-processed in the task manager so we ignore it in the
task.
We also make sure to ignore such messages if the extension is disabled
and the peer already sent us one INFORMATIONAL, e.g. a DPD (we'd otherwise
consider the message with MID 0 as a retransmit).
If the responder never sent a message the expected MID is 0. While
the sent MID (M1) SHOULD be increased beyond the known value, it's
not necessarily the case.
Since M2 - 1 would then equal UINT_MAX setting that MID would get ignored
and while we'd return 0 in the notify we'd actually expect 1 afterwards.
If a responder is natted it will usually be a static NAT (unless it's a
mediated connection) in which case adding these notifies makes not much
sense (if the initiator's NAT mapping had changed the responder wouldn't
be able to reach it anyway). It's also problematic as some clients refuse
to respond to DPDs if they contain such notifies.
Fixes#2126.
If we silently delete the IKE_SA the other peer might still use it even
if only to send DPDs. If we don't answer to DPDs that might result in the
deletion of the new IKE_SA too.
This is the minimum size an IPv6 implementation must support. This makes
it the default for IPv4 too, which presumably is also generally routable
(otherwise, setting this to 0 falls back to the minimum of 576 for IPv4).
They are only required if drop policies would otherwise prevent
forwarding traffic. This reduces the number of policies and avoids
conflicts e.g. with SPD hash thresholds.
Some tasks might get removed immediately once the IKE_SA_INIT response has
been handled even if there were notifies that require a restart of the
IKE_SA (e.g. COOKIE or INVALID_KE_PAYLOAD). Such a task is ike_vendor,
which caused vendor IDs not to get sent in a retry. This change ensures
all required tasks are queued after the reset, which some callers did
already anyway.
These seem to indicate the major and minor version of the protocol, like
e.g. for the DPD vendor ID. Some implementations seem to send versions
other than 1.0 so we just ignore these for now when checking for known
vendor IDs.
Fixes#2088.
By aborting the active task we don't have to wait for potential
retransmits if the other peer does not respond to the current task.
Since IKEv1 has no sequential message IDs and INFORMATIONALs are no real
exchanges this should not be a problem.
Fixes#1537
References #429, #1410Closesstrongswan/strongswan#48
Depending on the lifetimes a CHILD_SA we rekeyed as responder might
expire shortly afterwards. We don't want to rekey it again.
When retrying due to an INVALID_KE_PAYLOAD notify the expected state
is CHILD_REKEYING if it is anything else (e.g. due to a collision) we
ignore it.
We also abort the exchange properly if we don't find the CHILD_SA, no
need for an empty INFORMATIONAL exchange anymore.
If a passive rekeying fails due to an INVALID_KE_PAYLOAD we don't want
to consider this task later when resolving collisions. This previously
might have caused the wrong SA to get deleted/installed based on the nonces
in the unsuccessful exchange.
Such a task is not initiated unless a certain time has passed. This
allows delaying certain tasks but avoids problems if we'd do this
via a scheduled job (e.g. if the IKE_SA is rekeyed in the meantime).
If the IKE_SA is rekeyed the delay of such tasks is reset when the
tasks are adopted i.e. they get executed immediately on the new IKE_SA.
This hasn't been implemented for IKEv1 yet.
If the peer does not detect the rekey collision and deletes the old
IKE_SA and then receives the colliding rekey request it will respond with
TEMPORARY_FAILURE. That notify may arrive before the DELETE does, in
which case we may just conclude the rekeying initiated by the peer.
Also, since the IKE_SA is destroyed in any case when we receive a delete
there is no point in storing the delete task in collide() as process_i()
in the ike-rekey task will never be called.
We conclude the rekeying before deleting the IKE_SA. Waiting for the
potential TEMPORARY_FAILURE notify is no good because if that response
does not reach us the peer will not retransmit it upon our retransmits
of the rekey request if it already deleted the IKE_SA after receiving
our response to the delete.
Tobias Brunner