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).
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.
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 that scenario).