This can happen if an IKE_SA is initiated to a static IP before DHCP is
done. Instead of failing the initiation, we either fake a NAT situation
(for IPv4) or disable NAT-D (for IPv6 where NATs and UDP-encap are not
widely used or supported).
This also removes the old fallbacks to determine the source address(es).
A source address lookup is done in ike_sa_t::resolve_hosts() (wasn't the
case initially) and enumerating local IPs (which was added even earlier)
could still lead to issues if e.g. LAN addresses are available but the
WAN address that's later used is not yet (in which case only the responder
would detect a NAT and UDP-encap would be configured asymmetrically).
To force UDP-encap locally in case there is no actual NAT, we store this
as COND_NAT_HERE instead of COND_NAT_FAKE. This ensures DPDs will contain
NAT-D notifies and we can later remove the state via MOBIKE. We trigger
a MOBIKE update after such a DPD by registering a changed NAT mapping after
checking for a disappearing local NAT, which is very unlikely to happen
outside of a MOBIKE update (where that flag is not checked).
Without this, the authentication succeeded if the server sent an early
EAP-Success message for mutual, key-generating EAP methods like EAP-TLS,
which may be used in EAP-only scenarios but would complete without server
or client authentication. For clients configured for such EAP-only
scenarios, a rogue server could capture traffic after the tunnel is
established or even access hosts behind the client. For non-mutual EAP
methods, public key server authentication has been enforced for a while.
A server previously could also crash a client by sending an EAP-Success
immediately without initiating an actual EAP method.
Fixes: 0706c39cda ("added support for EAP methods not establishing an MSK")
Fixes: CVE-2021-45079
This is useful for kernel implementations where the ordering of SAs
is unpredictable and the new SA might otherwise not be used until the
DELETE response has been received, which is not ideal as the responder
might not keep the old SA around that long. On Linux, it makes no
difference as we switch to the new outbound SA immediately because the
updated outbound policy references its SPI.
Currently the length of vendor ID Cisco VPN Concentrator is 16
bytes but the string has only 13+1 bytes. The actual vendor
ID has 16 bytes with a prefix length of 14 bytes and two version
bytes.
Fixes: 6c49ddfbca ("ike: Add additional Vendor IDs for third-party implementations")
Before commit 6c49ddfbca ("ike: Add additional Vendor IDs for
third-party implementations") the prefix length of vendor ID
Cisco Unity was hardcoded to 14. Since we need to know the actual
length of this VID to send it, the length can't be overloaded
with a prefix length. Revert part of commit 6c49ddfbca to
fix this problem.
Fixes: 6c49ddfbca ("ike: Add additional Vendor IDs for third-party implementations")
Before commit 6c49ddfbca ("ike: Add additional Vendor IDs for
third-party implementations") the prefix length of vendor ID
MS NT5 ISAKMPOAKLEY was hardcoded to 16. Change the prefix length
accordingly.
Fixes: 6c49ddfbca ("ike: Add additional Vendor IDs for third-party implementations")
If there are many CHILD_SAs, the time between initiating the new IKE_SA
and checking it in might be longer (depending on what else is going on
in the daemon) than the retransmission timeout and no retransmits might
be sent afterwards for this SA (it will just linger around dead).
Calling initiate() last should avoid that (we do this similarly for MBB
reauthentication).
If we are using make-before-break reauthentication, this could lead to
duplicates as the new IKE_SA wouldn't be able to delete the previous
one if it was replaced by a rekeying.
If we initiated a make-before-break reauthentication and the peer
concurrently deletes the IKE_SA (e.g. because it uses break-before-make
reauthentication), we would create a duplicate IKE_SA (the condition forces
a recreation of all existing CHILD_SAs because reestablish() is also called
to complete a break-before-make reauthentication).
The addresses observed by the client behind the NAT are exactly the same if
the NAT router gets restarted.
Fixes: 2b255f01af ("ike-mobike: Use ike_sa_t::update_hosts() to trigger events")
This now includes all key material derived for IKE_SAs in the order
defined in the RFC:
{SK_d | SK_ai | SK_ar | SK_ei | SK_er | SK_pi | SK_pr}
= prf+ (SKEYSEED, Ni | Nr | SPIi | SPIr)
Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
For some that are followed by unknown data (e.g. detailed version
information) we only do a prefix match.
Co-authored-by: Tobias Brunner <tobias@strongswan.org>
Closesstrongswan/strongswan#393.
The job is queued properly, yet the timing information is wrong.
Signed-off-by: Stefan Berghofer <stefan.berghofer@secunet.com>
Fixes: ee61471113 ("implemented RFC4478 (repeated authentication)...")
If the reauthentication is scheduled while rekeying, the difference
might be negative, however, schedule_job() takes an unsigned int,
so the reauth would get scheduled very far in the future.
If rekeying and reauthetication coincided, the reauth job could get
scheduled to run immediately i.e. before checkin() was called. So the
new IKE_SA would not get reauthenticated, however, the further delayed
delete job would later find the new IKE_SA and delete it.
This way, jobs for new IKE_SAs (created via create_new()) may be
scheduled/queued before checkin() is called. If they run before
that happens, they will now correctly block in checkout() instead of
doing nothing because the IKE_SA was not found.
We don't actually check that SA out (i.e. it's not registered with the
manager). That was originally different but had to be changed with
86993d6b90 to avoid that SAs created for rekeying don't block other
threads on the manager.
These changes should ensure that concurrent calls to checkout_by_config()
result in a single IKE_SA. For instance, when acquires for different
children of the same connection are triggered concurrently.
There are two major changes to the interface:
1) The peer config object is now always set on the returned IKE_SA.
That was previously only the case if an existing IKE_SA was
returned.
2) The IKE_SA is now always registered with the manager and properly
checked out, which also was only the case for existing IKE_SAs
before.
This allows more fine grained control over what's updated and does not
require multiple calls of the method. Plus we'll be able to use it in
the ike-mobike task.
If we are already deleting the old/redundant CHILD_SA, we must not
migrate the child-create task as that would destroy the new CHILD_SA we
already moved to the IKE_SA.
Fixes#3644.
The message_t object used for defragmentation was only cleared after
all fragments have been received and the message was delivered. So
if we received only some fragments of a retransmitted message, the
fragments of the next message were not processed (message_t returns
INVALID_ARG if the message ID does not match causing the message to
get ignored). This rendered the IKE_SA unusable as the client
obviously never retransmitted the fragments of that previous message
after it received our response.
We create the child_sa_t object when initiating the CREATE_CHILD_SA
request, however, the IP addresses/ports might have changed once we
eventually receive the response (potentially to a retransmit sent to
a different address). So update them before installing the SA and
policies.
If the local address changed too and depending on the kernel
implementation, the temporary SA created to allocate the inbound SPI
might remain as it can't be updated. This could cause issues if e.g.
the address switches back before that SA expired (the updated inbound
SA conflicts with the temporary one), or if that happens close together
and the expire (having to wait for the address update) causes the
updated SA to get deleted.
Fixes#3164.
A new global option enables sending this vendor ID to prevent Cisco
devices from narrowing the initiator's local traffic selector to the
requested virtual IP, so e.g. 0.0.0.0/0 can be used instead.
This has been tested with a "tunnel mode ipsec ipv4" Cisco template but
should also work for GRE encapsulation.
Closesstrongswan/strongswan#180.
If a MOBIKE task is deferred, the retransmission counter is reset to 0
when reinitiating. So if there were retransmits before, this alert would
not be triggered if a response is received now without retransmits.
We usually have a local IP already via ike_sa_t::resolve_hosts() before
build_i() is called but if that's not the case, it's more likely we have
one after we processed the first response (it might also have changed).
There is a potential chance we still don't have one if the socket API
doesn't provide us with the destination address of received messages,
but that seems not very likely nowadays.
We need the PSK/identity already when deriving the keys in process_i().
Fixes: 1665a4e050 ("ikev1: Use actual local identity as initiator or aggressive mode responder")
Retransmission jobs for old requests for which we already received a
response previously left the impression that messages were sent more
recently than was actually the case.
task_manager_t always defined INVALID_STATE as possible return value if
no retransmit was sent, this just was never actually returned.
I guess we could further differentiate between actual invalid states
(e.g. if we already received the response) and when we don't send a
retransmit for other reasons e.g. because the IKE_SA became stale.
Tobias Brunner