With SELinux and without a specific label from an acquire, we abort
establishing the CHILD_SA (for the first one we prefer a childless IKE_SA,
but since that's a separate extension, we fall back to letting the initial
CHILD_SA fail as we won't propose a label).
If trap policies are not installed already (e.g. because it's impossible to
do so like as responder for roadwarriors), this will require installing
them dynamically once the IKE_SA is established.
In SELinux mode we install the configured label on the policies and the
negotiated one on the SAs. This is how it usually is configured where the
policy/configuration has a generic context and the SAs will get the actual
context of the flows assigned (the latter matches the former, so flows
match the policies but will trigger an acquire if no matching SA exists).
In the simple mode we don't pass the label to the kernel and to avoid
duplicate policy errors we also don't use it to acquire unique reqids.
The security labels can be retrieved in a separate list from the
regular traffic selectors. We currently only plan to support a single
security label ourselves, so when generating we don't expect a list.
Changes how regular address range traffic selectors are parsed as the
IKE parser currently doesn't provide sub-type parsing.
Also removed a lot of unused method definitions.
While combining the actions could cause duplicates (while the SA is
initiated, traffic might trigger the trap and the initiation of another
CHILD_SA), the previous commit should avoid most duplicates. If reuse_ikesa
is disabled, duplicates can't be prevented, though.
This could happen if an acquire is triggered while we respond to a
CREATE_CHILD_SA request from the peer, or if an acquire is triggered
while an IKE_SA (with its existing CHILD_SAs) is reestablished (also
with break-before-make reauthentication). Also catches multiple
manual initiations.
Note that this ignores the traffic selectors from acquires (narrowing to
them seems rare in practice anyway).
Duplicates can still get created if e.g. both peers initiate them
concurrently.
If a policy with IPComp template triggers an acquire, we get two, one for
an IPComp, one for ESP/AH SA. However, the triggering template of the trap
policy (where we get the reqid from), will be the same in both acquires,
IPComp, which we ignore, so no acquire was actually forwarded.
These are set via methods, which are not called again after migration
(e.g. when retrying due to INVALID_KE or when moving queued tasks), so we
don't want to clear these values.
This should make the DoS limits (cookie_threshold[_ip] and block_threshold)
more accurate so that it won't be possible to create lots of jobs from
spoofed IP addresses before half-open IKE_SAs are actually created from
these jobs to enforce those limits.
Note that retransmits are tracked as half-open SAs until they are
processed/dismissed as the check only happens in checkout_by_message().
Increasing the count in process_message_job_create() avoids issues with
missing calls to track_init() before calling checkout_by_message() (e.g.
when processing fragmented IKEv1 messages, which are reinjected via a
process message job).
Because the global cookie threshold is higher than the per-IP block
threshold, it was previously possible for an attacker to block a legitimate
user by sending spoofed IKE_SA_INIT packets from that user's IP.
The timespan for requiring cookies is now also not extended anymore with
every IKE_SA_INIT received during the calm down period. Because this
allowed an attacker, after initially triggering the global cookie threshold,
to force cookies for all clients by sending just a single spoofed
IKE_SA_INIT every 10 seconds.
We keep track of reaching the per-IP threshold in segments of the hashed
IP addresses, so only a (random, due to chunk_hash()'s random key) subset
of clients will receive cookies, if single IPs are targeted.
The default global threshold is increased a bit.
If we are under attack and there are lots of requests, we might hit
the previous use count limit pretty quickly and may switch secrets multiple
times a second, which renders the 10 second default lifetime of COOKIEs
pointless and prevents legitimate clients from sending requests with valid
COOKIEs.
Such routes with a gateway that equals the peer's address are problematic
on FreeBSD. And since there is most likely a narrow route for the local
subnet anyway, the exclude routes would be redundant.
When installing routes based on remote traffic selectors, it can be
necessary to install an exclude route for the remote peer to avoid a
routing loop and continue to be able to reach it via IKE/ESP.
However, such routes are only necessary, if the routes we install don't
go via outbound interface. That's the case when using VIPs and routing
via TUN devices, or when using internal source IPs and routing via
their interfaces.
Installing such exclude routes if not necessary can cause issues on
FreeBSD (EINVAL when sending packets to the peer).
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).
strongSwan logs all syslog messages using LOG_INFO for historical reasons,
regardless of the strongSwan loglevel used producing the log message.
In some setups with advanced logging infrastructure, it may be feasible
to be more verbose when logging in strongSwan, but then filter messages
on the syslog server. While this may be possible by custom syslog filtering
rules matching the log level included with the log_level setting, this is
not super convenient.
So add a new map_level setting, which can map strongSwan loglevels to
syslog loglevels. By default this is disabled, keeping the existing
behavior. If enabled, it maps strongSwan loglevels to syslog loglevels
at a given syslog loglevel offset.
Closesstrongswan/strongswan#859
RFC3779 requires to validate the addrblocks of issuer certificates strictly,
that is, they must contain the extension and the claimed addrblock, up to
the root CA.
When working with third party root CAs that do not have the extension,
this makes using the plugin impossible. So add a depth setting that limits
the number of issuer certificates to check bottom-up towards the root CA.
A depth value of 0 disables any issuer check, the default value of -1
checks all issuers in the chain, keeping the existing behavior.
Closesstrongswan/strongswan#860
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.
The default MTU of 1500 is too high if kernel-libipsec is used (considering
the overhead of UDP-encapsulated ESP), but might also have an effect if
a TUN device is only used to install a virtual IP (the route points to it,
so the system might use its MTU and 1500 would still be too high).
This also works around an issue on macOS 12 where no RTM_IFINFO event
is sent for the newly created TUN device (neither for the creation,
setting it "up", nor adding the address). Changing the MTU, however,
triggers such an event and we can detect the virtual IP.
Closesstrongswan/strongswan#707
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")
Tobias Brunner