Support of Diffie-Hellman group 31 using Curve25519 for IKE as defined by RFC 8031 is provided by the new curve25519 plugin.
Support of Ed25519 digital signature algorithm for IKEv2 as defined by draft-ietf-ipsecme-eddsa is provided by the new curve25519 plugin. Ed25519-based public key pairs, X.509 certificates and CRLs can be generated and printed by the pki tool.
The new tpm libtpmtss plugin allows to use persistent private RSA and ECDSA keys bound to a TPM 2.0 for both IKE and TLS authentication. Using the TPM 2.0 object handle as keyid parameter, the pki --pub tool can extract the public key from the TPM thereby replacing the aikpub2 tool. In a similar fashion pki --req can generate a PKCS#10 certificate request signed with the TPM private key. Optionally the tpm plugin may be used as RNG.
The pki tool gained support for generating certificates with RFC 3779 addrblock extensions. The charon addrblock plugin now dynamically narrows traffic selectors based on the certificate's addrblocks instead of rejecting non-matching selectors completely. This allows generic connections, where the allowed selectors are defined by the used certificates only.
The optional bypass-lan plugin automatically installs and updates passthrough/bypass policies for locally attached subnets. This is useful for mobile hosts that are used in different networks that want to access local devices in these networks (e.g. printers or NAS) while connected to a VPN.
A command injection vulnerability in the ipsec script was fixed, which was exploitable if unprivileged users were allowed to run the script via sudo (2ec6372f5a). Thanks to Andrea Barisani for reporting this.
Several new features for the VICI interface and the swanctl utility were added:
Enumerating and unloading private keys and shared secrets (swanctl --load-creds now automatically unloads removed secrets)
Loading keys and certificates from PKCS#11 tokens or a TPM (refer to the documentation of cert<suffix> and token<suffix> sections in swanctl.conf)
The ability to initiate, install and uninstall connections and policies by their exact name (if multiple child sections in different connections share the same name)
Querying a specific pool
A command to initiate the rekeying of IKE and IPsec SAs
Public keys may be configured directly in swanctl.conf via 0x/0s prefix (actually works for certificates too)
The overhead of the VICI logger has been reduced as it now only does something if listeners are registered
Support for settings previously only supported by the old config files: DSCP, certificate policies, IPv6 Transport Proxy Mode, NT hash secrets, mediation extension
In-place update of cached base and delta CRLs does not leave dozens of stale copies in cache memory.
Support for handling IKEV2_MESSAGE_ID_SYNC notifies as responder (usually the original initiator of an IKE_SA) as defined in RFC 6311 was added. Some HA solutions use these notifies to set the new IKEv2 message IDs after a failover event (currently not our HA solution, though).
By default, the IKE daemon keeps SAs on the routing path with addresses it previously used if that path is still usable. Enabling charon.prefer_best_path changes that and it will try more aggressively to update SAs with MOBIKE on routing changes using the cheapest path. This adds more noise, but allows to dynamically adapt SAs to routing priority changes, for instance, if some paths actually generate more costs than others (597e8c9e00).
If MOBIKE is disabled and the local address is statically configured the daemon will now ignore any roaming events that might, otherwise, cause it to attempt to recreate the IKE_SA (be27e76869).
Trap policies now use priorities from the same range as regular policies, which allows installing overlapping trap policies (#1243).
When proposing transport mode the IKE daemon now always applies the hosts to the traffic selectors. It previously only did so if %dynamic was used as TS. However, that's not the case if wildcard trap policies are configured (no single remote address specified). Once traffic matched, the daemon proposed the configured remote TS as-as, which the responder then had to narrow down to its own local address. Some third-party implementations, however, reject such non-host TS for transport mode SAs (da82786b2d).
For AH the kernel-netlink plugin now enables the correct 4 byte alignment (by default, the kernel uses an 8 byte alignment, which is mandatory for IPv6 but prohibited for IPv4, 965daa1df3).
The kernel-netlink plugin now considers labels when selecting IPv6 addresses (#2138) and sets the NODAD flag for virtual IPv6 addresses to avoid issues with failing DAD (#2183).
The receive buffer size used by the kernel-netlink plugin is now configurable (8a91729dfe).
Large responses to Netlink requests are now concatenated more efficiently by the kernel-netlink plugin (6fe1d78a0d).
If route installation is disabled (charon.install_routes) the kernel-netlink plugin now uses a more efficient route lookup to determine source and next-hop addresses (558691b3b0).
No mark is installed anymore on inbound IPsec SAs. So explicitly marking inbound traffic before decryption is not necessary anymore (067fd2c69c).
The range from which SPIs for IPsec SAs are allocated by the kernel is now configurable.
PSKs for IKEv1 connections are now first looked up based on configured identities of connections that match the IPs, before falling back to searching for PSKs for the IPs (#2223).
The daemon now responds to DPDs for rekeyed IKEv1 SAs (#2090).
charon-systemd now reloads strongswan.conf, the loggers and the plugins (that support it) when it receives a SIGHUP. The same may be achieved via VICI's reload-settings command, which previously did not reload the loggers.
Validation via OCSP and CRLs can be disabled individually in the revocation plugin.
RFC 5114 DH groups were removed from the default proposal (649537ee8d), they may be used if configured explicitly.
A memory leak was fixed when CHILD_SA configs were updated via VICI (da1d5cd2e6).
The plugin loader now correctly hashes registered plugin features (ac4942c3c3).
Notes for developers:
Due to issues with VICI bindings that map sub-sections to dictionaries (e.g. Python) the CHILD_SA sections returned via list-sas now have a unique name. The original name of a CHILD_SA is returned in the name key of its section.
To simplify loading certificates via VICI when running on the same host as the daemon absolute paths to certificates (instead of their binary encoding) may be passed via cert<suffix> sections (file key).
The load-testconfig script now loads the configs from the source directory and pre-processes them properly (previously it was required to run do-tests once for the target scenario).
The newhope plugin implements the post-quantum NewHope key exchange algorithm proposed in their 2015 paper by Erdem Alkim, Léo Ducas, Thomas Pöppelmann and Peter Schwabe.
The libstrongswan crypto factory now offers the registration of Extended Output Functions (XOFs). Currently supported XOFs are SHAKE128 and SHAKE256 implemented by the sha3 plugin, ChaCHa20 implemented by the chapoly plugin and the more traditional MGF1 Mask Generation Functions based on the SHA-1, SHA-256 and SHA-512 hash algorithms implemented by the new mgf1 plugin.
By default, the "outbound" FWD policies, introduced with 5.5.0, are not installed anymore. They may be enabled via the policies_fwd_out setting in swanctl.conf/vici for a specific CHILD_SA if its traffic would otherwise get blocked by a drop policy. A bug in regards to updating reqids in the kernel-netlink plugin, that was particularly a problem with duplicate "outbound" FWD policies, has also been fixed (175d78df60).
XFRM policy hashing thresholds may be configured via strongswan.conf. This can significantly improve the performance on hosts where the number of flows exceeds the flow cache size of the Linux kernel. Policies covering more than a single address don't get hash-indexed by default, which results in wasting most of the cycles in xfrm_policy_lookup_bytype() and the called xfrm_policy_match(). Since Linux 3.18 the kernel can hash the first n-bit of a policy subnet to perform indexed lookups. With correctly chosen thresholds this can completely eliminate the performance impact of policy lookups. Note: Due to a bug in Linux 3.19 through 4.7, the kernel crashes with a NULL pointer dereference if a socket policy (used by strongSwan to exempt IKE traffic from IPsec tunnels) is installed while hash thresholds are changed. See ac9759a532 for details and a workaround.
The NetworkManager integration has been updated to support NM 1.2. The directory from which CA certificates are loaded if no certificate is configured in the GUI can now be configured via strongswan.conf using the new charon-nm.ca_dir setting.
IKE fragmentation is now enabled by default with the default fragment size set to 1280 bytes for both IP address families.
A DELETE is sent when a rekeyed IKEv1 SA is deleted. This fixes issues with peers that continue to send DPDs on the old SA and then delete all SAs if no response is received (see #2090). Also, when terminating IKEv1 SAs, DELETEs for all CHILD_SAs are now sent before sending one for the IKE_SA and destroying it.
The pki tool, with help of the pkcs1 or openssl plugins, can parse private keys in any of the supported formats without having to know the exact type. So instead of having to specify rsa or ecdsa explicitly the keyword priv may be used to indicate a private key of any type. Similarly, swanctl can load any type of private key from the swanctl/private directory.
The pki tool can handle RSASSA-PKCS1v1.5-with-SHA-3 signatures using the sha3 and gmp plugins.
The VICI flush-certs command flushes certificates from the volatile certificate cache. Optionally the type of the certificates to be flushed (e.g. type = x509_crl) can be specified.
When setting charon.cache_crls = yes in strongswan.conf the vici plugin saves regular, base and delta CRLs to disk. Fetched CRLs are now also cached if the checked certificate has been revoked.
The serial number for delta CRLs generated by pki --signcrl is now based on the given base CRL again (was broken since 4.6.3).
Delta CRLs are now properly cached in-memory (and on disk) together with their base. Before this the presence of a delta CRL might have required that the base be refetched every time.
When verifying trust chains with pki --verify local CRLs may now be specified with the new --crl argument.
IKE and ESP/AH proposals configured as strings in ipsec.conf and swanctl.conf (or VICI) are now checked to avoid invalid proposals. For instance, the presence of DH, PRF and encryption algorithms for IKE proposal are now enforced and AEAD and regular encryption algorithms are not allowed in the same proposal anymore. Also fixed is the mapping of the aes*gmac keywords to an integrity algorithm in AH proposals.
Unmarked packets may now be matched by setting 0/0xffffffff as XFRM mark (33d3ffde25).
The maximum registered log level is now determined correctly if loggers implementing only log or vlog are mixed (dac15e03c8).
In addition to the existing ike_keys and child_keys hooks on listener_t two new hooks allow listeners to receive the derived IKE and CHILD_SA keys (ike|child_derived_keys).
The check for libatomic has been improved (6e19a1f5f2).
The use of AES-GCM with BoringSSL has been fixed (c72c6e9225).
libtpmtss: In the TSS2 API the function TeardownSocketTcti() was replaced by tss2_tcti_finalize().
The results of leak-detective are now evaluated in our testing environment, which lead to the fixing of several memory leaks.
No key and self-signed certificate is generated by starter anymore if ipsec.secrets does not exist.
The long unmaintained Maemo plugin and frontend have been removed.
The new libtpmtss library offers support for both TPM 1.2 and TPM 2.0 Trusted Platform Modules. This allows the Attestation IMC/IMV pair to do TPM 2.0 based attestation.
The behavior during IKEv2 exchange collisions has been improved/fixed in several corner cases and support for TEMPORARY_FAILURE and CHILD_SA_NOT_FOUND notifies, as defined by RFC 7296, has been added (#379, #464, #876, #1293). The behavior is tested with a series of new unit tests.
IPsec policy priorities can be set manually (e.g. for high-priority drop policies) and outbound policies may be restricted to a network interface. These options are only configurable via swanctl.conf. An example is provided in the swanctl/manual-prio scenario.
The scheme for the automatically calculated default priorities has been changed and now also considers port masks, which were added with 5.4.0 (for details see d3af3b799f).
FWD policies are now installed in both directions in regards to the traffic selectors (9c12635252). Because such "outbound" FWD policies could conflict with "inbound" FWD policies of other SAs (as, for example, in the swanctl/net2net-gw or the ikev2/ip-two-pools-db scenarios) they are installed with a lower priority and don't have a reqid set, which allows kernel plugins to distinguish between the two and prefer those with a reqid.
How the interface for routes installed with policies is determined has changed (96b1fab53c). In most cases the interface over which the other peer is reached is now used, not the interface on which the local address (or the source IP) is installed. However, that might be the same interface depending on the configuration (i.e. in practice there will often not be a change).
No routes are installed anymore for drop policies and policies with port/protocol selector (e7369a9dc5).
For outbound IPsec SAs no replay window is configured anymore.
When using unique marks (mark=%unique) the allocated mark is now correctly passed to the updown script (b210369314).