This is because OpenSSL 1.1 started to use atexit()-handlers of its own
to clean up. Since the plugin is loaded and initialized after libcharon,
OpenSSL's cleanup functions ran before the daemon was properly
deinitialized (i.e. worker threads were still running and OpenSSL might
still be used during the deinit). So several of OpenSSL's internal
structures were already destroyed when libcharon_deinit() was eventually
called via our own atexit()-handler.
The observed behavior was that the daemon couldn't be terminated properly
anymore for some test scenarios (only three TNC scenarios were affected
actually). When the daemon tried to send the DELETE for the established
IKE_SA during its termination it got stuck in OpenSSL's RNG_WEAK
implementation (used to allocate random padding), which apparently tries
to acquire an rwlock that was already destroyed. The main thread then
just busy-waited indefinitely on the lock, i.e. until systemd killed
it eventually after a rather long timeout.
We'll probably have to apply similar changes to other apps/scripts that
load plugins and currently use atexit() to clean up. Although some
scripts (e.g. dh_speed or hash_burn) are not affected because they
register the deinitialization after loading the plugins.
If a lot of QUICK_MODE tasks are queued and the other side
sends a DPD request, there is a good chance for timeouts.
Observed this in cases where other side is quite slow in responding
QUICK_MODE requests (e.g. Cisco ASA v8.x) and about 100 CHILD_SAs
are to be spawned.
Closesstrongswan/strongswan#115.
Checking for whitelisted functions in every backtrace is not very
efficient. And because OpenSSL 1.1 does no proper cleanup anymore until
the process is terminated there are now a lot more "leaks" to ignore.
For instance, in the openssl-ikev2/rw-cert scenario, just starting and
stopping the daemon (test vectors are checked) now causes 3594 whitelisted
leaks compared to the 849 before. This prolonged the shutdown of the
daemon on each guest in every scenario, amounting to multiple seconds of
additional runtime for every affected scenario. But even with this
patch there is still some overhead, compared to running the scenarios on
jessie.
RC4, which was previously used for performance reasons, is not supported
anymore with newer versions of SSH (stretch still supports it, but it
requires explicit configuration on the guests when they act as clients
too - the version in Ubuntu 18.04 apparently doesn't support it anymore
at all).
AES-GCM should actually be faster (at least for larger amounts of data and
in particular with hardware acceleration).
ClientAuthentication is known in OpenSSL 1.1 and the redefinition, therefore,
causes an error. These two OIDs are not used anyway in these config
files.
Tobias Brunner