This way we don't rely on the order of equally matching configs as
heavily anymore (which is actually tricky in vici) and this also doesn't
require repeating weak algorithms in all configs that might potentially be
selected if there are some clients that require them.
There is currently no ordering, so an explicitly configured exactly matching
proposal isn't a better match than e.g. the default proposal that also
contains the proposed algorithms.
This is currently not an issue for CHILD_SA rekeying tests as these only
check rekeyings of the CHILD_SA created with the IKE_SA, i.e. there is
no previous DH group to reuse.
This way we get proper error handling if the DH group the peer requested
is not actually supported for some reason (otherwise we'd just retry to
initiate with the configured group and get back another notify).
In case we send retransmits for an IKE_SA_INIT where we propose a DH
group the responder will reject we might later receive delayed responses
that either contain INVALID_KE_PAYLOAD notifies with the group we already
use or, if we retransmitted an IKE_SA_INIT with the requested group but
then had to restart again, a KE payload with a group different from the
one we proposed. So far we didn't change the initiator SPI when
restarting the connection, i.e. these delayed responses were processed
and might have caused fatal errors due to a failed DH negotiation or
because of the internal retry counter in the ike-init task. Changing
the initiator SPI avoids that as we won't process the delayed responses
anymore that caused this confusion.
This allows for different signature schemes for IKE authentication and
trustchain verification.
Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
An attacker could blindly send a message with invalid nonce data (or none
at all) to DoS an initiator if we just destroy the SA. To prevent this we
ignore the message and wait for the one by the correct responder.
Returning FAILED in the constructor is wrong, but returning NULL doesn't work
either as it's currently assumed tasks always can be created.
Therefore, delay this check until we actually try to allocate a nonce.
This allows to control the life-cycle of a nonce in the context of the
ike init task. In the TKM use-case the nonce generator cannot be
destroyed before the ike init task is finalized, otherwise the created
nonce is detected as stale.
Thomas Egerer