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.
If the SA got redirected this would otherwise cause a reauthentication with
the original gateway. Reestablishing the SA to the original gateway, if e.g.
the new gateway is not reachable makes sense though.
We handle this similar to how we do reestablishing IKE_SAs with all CHILD_SAs,
which also includes the one actively queued during IKE_AUTH.
To delete the old SA we use the recently added ike_reauth_complete task.
To prevent the creation of the CHILD_SA we set a condition on the
IKE_SA. We also schedule a delete job in case the client does not
terminate the IKE_SA (which is a SHOULD in RFC 5685).
According to the mode-config draft there is no prefix sent for
IPv6 addresses in IKEv1. We still accept 17 bytes long addresses for
backwards compatibility with older strongSwan releases.
Fixes#1304.
When charon rekeys a CHILD_SA after a soft limit expired, it is only
deleted after the hard limit is reached. In case of packet/byte limits
this may not be the case for a long time since the packets/bytes are
usually sent using the new SA. This may result in a very large number of
stale CHILD_SAs and kernel states. With enough connections configured this
will ultimately exhaust the memory of the system.
This patch adds a strongswan.conf setting that, if enabled, causes the old
CHILD_SA to be deleted by the initiator after a successful rekeying.
Enabling this setting might create problems with implementations that
continue to use rekeyed SAs (e.g. if the DELETE notify is lost).
If it was necessary to pass the local certificates we could probably
clone the config (but we don't do that either when later looking for the
key to actually authenticate).
Passing auth adds the same subject cert to the config over and over
again (I guess we could also try to prevent that by searching for
duplicates).
If there is no path to the other peer there is no point in trying to
send a NAT keepalive.
If the condition changes back and forth within the keepalive interval there
is a chance that multiple jobs get queued.
This could be helpful when debugging deadlocks that manifest around
wait_for_entry(), as it helps identifying other involved threads (the
thread object is seen in the thread_main() call in each thread's backtrace).
With IKEv1 we have to reuse IKE_SAs as otherwise the responder might
detect the new SA as reauthentication and will "adopt" the CHILD_SAs of
the original IKE_SA, while the initiator will not do so. This could
cause CHILD_SA rekeying to fail later.
Fixes#1236.
When handling a rekey collision we might have to delete an already
installed redundant CHILD_SA (or expect the other peer to do so).
We don't want to trigger updown events for these as neither do we do
so for successfully rekeyed CHILD_SAs.
Fixes#853.
If the retransmit of an initial message is processed concurrently with the
original message it might not have been handled as intended as the
thread processing the retransmit might not have seen the correct value
of entry->processing set by the thread handling the original request.
For IKEv1, i.e. without proper message IDs, there might still be races e.g.
when receiving a retransmit of the initial IKE message while processing the
initiator's second request.
Fixes#1269.
If we mistakenly detect a new IKE_SA as a reauthentication the client
won't request the previous virtual IP, but since we already migrated
it we already triggered the assign_vips() hook, so we should reassign
the migrated virtual IP.
Fixes#1152.
We already did so during Phase 1 but because all three Quick Mode
message have the same message ID we occasionally dropped the third
message as retransmit, so we do it there too. For INFORMATIONAL
and TRANSACTION exchanges we don't expect more than one inbound message
with the same message ID so we still use them there.
Fixes#1198.
In some scenarios an IKE_SA might get restarted multiple times (e.g.
due to retransmits and delayed INVALID_KE_PAYLOAD notifies) so that
two IKE_SA_INIT messages might be sent that only differ in the
previously randomly generated NAT_DETECTION_SOURCE_IP payload.
This could cause an authentication failure on the responder if the two
peers don't use the same IKE_SA_INIT message in their InitiatorSignedOctets.
While the payload is generated in a reproducible way it will still change
when the daemon is restarted, which should make detecting the payloads
as fake a bit harder (compared to e.g. just using 0.0.0.0:0 as address).
Fixes#1131.
In some cases we call wait_for_entry() but don't actually check out the
entry afterwards (e.g. because it doesn't match certain criteria). So
there won't be a call to checkin() for such entries causing waiting
threads to get signaled. Instead, such threads would be blocked until
another thread properly checks out/in the entry (or does a blocking
enumeration).
If we haven't received the third QM message for multiple exchanges the
return value of NEED_MORE for passive tasks that are not responsible for
a specific exchange would trigger a fourth empty QM message.
Fixes: 4de361d92c ("ikev1: Fix handling of overlapping Quick Mode exchanges")
References #1076.
Previously, the current segment was held while checking for duplicate
SAs, which requires acquiring all segments. If multiple threads did this
concurrently this resulted in a deadlock as they couldn't acquire the
segments held by the other threads attempting to do the same. With the
default configuration only one segment is used, which prevents the problem
as only one thread can check in an IKE SA concurrently.
Fixes: a064eaa8a6 ("Handling of initial contact")
left|rightsubnet default to %dynamic, which is basically 0.0.0.0/0 until an
address is assigned to it. So if only one side was undefined and the other
traffic selector was IPv6 an address family mismatch would occur.
References #595.
When retrying due to a DH group mismatch this is already done by the
child-create task itself. And in other cases where the task returns
NEED_MORE we actually will need access to a possible proposal to properly
delete it.
If the responder declines our KE payload during a CHILD_SA rekeying migrate()
is called to reuse the child-create task. But the child-rekey task then
calls the same method again.
Fixes: 32df0d81fb ("child-create: Destroy nonceg in migrate()")
In some cases the third message of a Quick Mode exchange might arrive
after the first message of a subsequent Quick Mode exchange. Previously
these messages were handled incorrectly and the second Quick Mode
exchange failed.
Some implementations might even try to establish multiple Quick Modes
simultaneously, which is explicitly allowed in RFC 2409. We don't fully
support that, though, in particular in case of retransmits.
Fixes#1076.
If multiple certificates use the same subjects we might choose the wrong
one otherwise. This way we use the one referenced with leftcert and
stored in the auth-cfg and we actually do the same thing later in the
pubkey authenticator.
Fixes#1077.
This allows symmetric configuration of EAP methods (i.e. the same value
in leftauth and rightauth) when mutual EAP-only authentication is used.
Previously the client had to configure rightauth=eap or rightauth=any,
which prevented it from using this same config as responder.
When reestablishing the IKE_SA we should still use the original port
when right resolves to %any as some implementations might not like
initial IKE messages on port 4500 (especially for IKEv1).
During a rekeying we want to reuse the current reqid, but if the new SA
does not allocate it via kernel-interface the state there will disappear
when the old SA is destroyed after the rekeying. When the IKE_SA is
later reauthenticated with make-before-break reauthentication the new
CHILD_SAs there will get new reqids as no existing state is found in the
kernel-interface, breaking policy installation in the kernel.
Fixes: a49393954f ("child-sa: Use any fixed reqid configured on the CHILD_SA config")
Vendor specific EAP methods may be registered with:
PLUGIN_CALLBACK(eap_method_register, <constructor>),
PLUGIN_PROVIDE(EAP_SERVER_VENDOR, <type>, <vendor>),
Same for client implementations via EAP_PEER_VENDOR.
References #969.
The destroy() method sets the IKE_SA on the bus to NULL, we reset it to
the current IKE_SA so any events and log messages that follow happen in
the correct context.
A practical example where this is problematic is a DH group mismatch,
which causes the first CREATE_CHILD_SA exchange to fail. Because the SA
was not reset previously, the message() hook for the CREATE_CHILD_SA
response, for instance, was triggered outside the context of an IKE_SA,
that is, the ike_sa parameter was NULL, which is definitely not expected
by several plugins.
Fixes#862.
When flush() is called there might be threads in install() waiting for
trap policies to get installed (without holding the lock). We have to
wait until they updated the entries with the respective CHILD_SAs before
destroying the list.
We also have to prevent further trap policy installations (and wait until
threads in install() are really finished), otherwise we might end up
destroying CHILD_SA objects after the kernel interface implementations
have already been unloaded (avoiding this is the whole point of calling
flush() before unloading the plugins).
This fixes potential race conditions in case complete() or flush() is
executed before or concurrently with a thread that handles an acquire.
It will also simplify tracking multiple acquires created for the same
trap policy in the future.
Also fixes the behavior in some error situations.
This basically reverts f4e822c1b4 ("trap-manager: don't check-in
nonexisting IKE_SA if acquire fails"). As checkout_by_config() could
return an already existing and established IKE_SA we have to properly
destroy it, for instance, in case other threads are waiting to check
it out. checkin_and_destroy() should handle the case of a new SA
properly (it produces a log message on level 1, though).
In some situations it might be valid for a host that configures
right=%any to reestablish or reauthenticate an IKE_SA. Using %any would
immediately abort the initiation causing the new SA to fail (which
might already have the existing CHILD_SAs assigned).
Fixes#1027.
If static local addresses are configured we should use their address family
as a hint when resolving the remote address.
We don't do this if %any is configured as this might break existing
configurations (%any4 and %any6 are however used as hint).
Threads might still be allocating SPIs (e.g. triggered by an acquire or
an inbound message) while the main thread calls flush(). If there is a
context switch right after such a thread successfully checked this->rng
in get_spi() and the main thread destroys the RNG instance right then,
that worker thread will cause a segmentation fault when it continues and
attempts to call get_bytes().
Fixes#1014.
Previously the constraints in the authentication configuration of an
initiator were enforced only after all authentication rounds were
complete. This posed a problem if an initiator used EAP or PSK
authentication while the responder was authenticated with a certificate
and if a rogue server was able to authenticate itself with a valid
certificate issued by any CA the initiator trusted.
Because any constraints for the responder's identity (rightid) or other
aspects of the authentication (e.g. rightca) the initiator had were not
enforced until the initiator itself finished its authentication such a rogue
responder was able to acquire usernames and password hashes from the client.
And if a client supported EAP-GTC it was even possible to trick it into
sending plaintext passwords.
This patch enforces the configured constraints right after the responder's
authentication successfully finished for each round and before the initiator
starts with its own authentication.
Fixes CVE-2015-4171.
Global reqid allocation (94eb09ac) broke fixed reqid allocation. Resupport them
by bypassing allocation in the kernel if a fixed reqid has been configured.
Fixes#976.
This fixes a DoS and potential remote code execution vulnerability that was
caused because the original payload type that was returned previously was
used to cast such payload objects to payloads of the indicated type (e.g.
when logging notify payloads with a payload type for the wrong IKE version).
Fixes CVE-2015-3991.
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.
This allows to control the life-cycle of a nonce in the context of the
child create task. In the TKM use-case, it is required to reset the
nonce context if the created nonce is not consumed. This happens if the
child SA negotiation fails and it is detected before the SA is
established via the TKM kernel plugin (i.e. rekey collision).
Real AEADs directly provide a suitable IV generator, but traditional crypters
do not. For some (stream) ciphers, we should use sequential IVs, for which
we pass an appropriate generator to the AEAD wrapper.
This is needed to handle DELETEs properly, which was previously done via
CHILD_REKEYING, which we don't use anymore since 5c6a62ceb6 as it prevents
reauthentication.
OpenBSD's isakmpd uses the latest ISAKMP SA to delete other expired SAs.
This caused strongSwan to delete e.g. a rekeyed SA even though isakmpd
meant to delete the old one.
What isakmpd does might not be standard compliant. As RFC 2408 puts
it:
Deletion which is concerned with an ISAKMP SA will contain a
Protocol-Id of ISAKMP and the SPIs are the initiator and responder
cookies from the ISAKMP Header.
This could either be interpreted as "copy the SPIs from the ISAKMP
header of the current message to the DELETE payload" (which is what
strongSwan assumed, and the direction IKEv2 took it, by not sending SPIs
for IKE), or as clarification that ISAKMP "cookies" are actually the
SPIs meant to be put in the payload (but that any ISAKMP SA may be
deleted).
The specific traffic selectors from the acquire events, which are derived
from the triggering packet, are usually prepended to those from the
config. Some implementations might not be able to handle these properly.
References #860.
Some clients like iOS/Mac OS X don't do a mode config exchange on the
new SA during re-authentication. If we don't adopt the previous virtual
IP Quick Mode rekeying will later fail.
If a client does do Mode Config we directly reassign the VIPs we migrated
from the old SA, without querying the attributes framework.
Fixes#807, #810.
If additional tasks get queued before/while rekeying an IKE_SA, these get
migrated to the new IKE_SA. We previously did not trigger initiation of these
tasks, though, leaving the task unexecuted until a new task gets queued.
We are actually not in rekeying state, but just trigger a separate, new IKE_SA
as a replacement for the current IKE_SA. Switching to the REKEYING state
disables the invocation of both IKE and CHILD_SA updown hooks as initiator,
preventing the removal of any firewall rules.
Fixes#885.
The current "inbound" flag is used for two purposes: To define the actual
direction of the SA, but also to determine the operation used for SA
installation. If an SPI has been allocated, an update operation is required
instead of an add.
While the inbound flag normally defines the kind of operation required, this
is not necessarily true in all cases. On the HA passive node, we install inbound
SAs without prior SPI allocation.
While the the meaning of the "inbound" flag on the kernel_interface->add_sa()
call is not very clear, we still need that update logic to allow installation of
inbound SAs without SPI allocation. This is used in the HA plugin as a passive
node.
This reverts commit 698ed656.
Previously, we failed without recovery if a private key did not support
a selected signature scheme (based on key strength and the other peer's
supported hash algorithms).
The payload we sent before is not compliant with RFC 2407 and thus some
peers might abort negotiation (e.g. with an INVALID-PROTOCOL-ID error).
Fixes#819.
If this is disabled the schemes configured in `rightauth` are only
checked against signature schemes used in the certificate chain and
signature schemes used during IKEv2 are ignored.
Disabling this could be helpful if existing connections with peers that
don't support RFC 7427 use signature schemes in `rightauth` to verify
certificate chains.
This enables late connection switching based on the signature scheme used
for IKEv2 and allows to enforce stronger signature schemes.
This may break existing connections with peers that don't support RFC 7427
if signature schemes are currently used in `rightauth` for certificate chain
validation and if the configured schemes are stronger than the default used
for IKE (e.g. SHA-1 for RSA).
We use the new signature authentication instead for this. This is not
backward compatible but we only released one version with BLISS support,
and the key format will change anyway with the next release.
The previous code allowed an attacker to slip in an IKE_SA_INIT with
both SPIs and MID 1 set when an IKE_AUTH would be expected instead.
References #816.
It is mandated by the RFCs and it is expected by the task managers.
Initial messages with invalid MID will be treated like regular messages,
so no IKE_SA will be created for them. Instead, if the responder SPI is 0
no SA will be found and the message is rejected with ALERT_INVALID_IKE_SPI.
If an SPI is set and we do find an SA, then we either ignore the message
because the MID is unexpected, or because we don't allow initial messages
on established connections.
There is one exception, though, if an attacker can slip in an IKE_SA_INIT
with both SPIs set before the client's IKE_AUTH is handled by the server,
it does get processed (see next commit).
References #816.
This reverts 8f727d8007 ("Clean up IKE_SA state if IKE_SA_INIT request
does not have message ID 0") because it allowed to close any IKE_SA by
sending an IKE_SA_INIT with an unexpected MID and both SPIs set to those
of that SA.
The next commit will prevent SAs from getting created for IKE_SA_INIT messages
with invalid MID.
Fixes#816.
Thomas Egerer