The HKDF-Expand() function defined in RFC 5869 is basically the same as
IKEv2's prf+(), so we can use the former to implement the latter.
However, we can only support HMAC-based PRFs this way, which should be
fine as others are rarely used.
This happens for `/0` subnet masks. In practice, it's not an issue because
if `bytes` is 0, then so are `netbits`, `bits` and `mask`. So the two
incorrectly addressed array elements are not actually modified. The first
operation is a `&= 0xff` and the second a `|= 0`, so nothing changes.
But some tools might not consider the values and report this as undefined
behavior, which it technically is.
There is a conflict between atexit() handlers registered by OpenSSL and
some executables (e.g. swanctl or pki) to deinitialize libstrongswan.
Because plugins are usually loaded after atexit() has been called, the
handler registered by OpenSSL will run before our handler. So when the
latter destroys the plugins it's a bad idea to try to access any OpenSSL
objects as they might already be invalid.
Fixes: f556fce16b ("openssl: Load "legacy" provider in OpenSSL 3 for algorithms like MD4, DES etc.")
Closesstrongswan/strongswan#921
The commit mentioned below adds an AES-GCM default proposal for ESP. That
proposal does not include any ESN or non-ESN transform to indicate if
extended sequence numbers are supported.
A standards-compliant peer will include one or more ESN support transforms,
and will be unable to select this proposal due to a proposal mismatch.
Fix the default AES-GCM proposal by adding a NO_ESN algorithm. While ESN has
been supported in the Linux kernel for a while, having it in the default
proposal can be problematic with kernel-libipsec or on other platforms.
Fixes: c7bef954ee ("proposal: Add AES-GCM to the ESP default AEAD proposal")
Closesstrongswan/strongswan#868
We still require these algorithms for e.g. EAP-MSCHAPv2, so the option is
enabled, by default. To use other providers (e.g. fips or even custom
ones), the option can be disabled and the providers to load/activate can
be configured in openssl.cnf. For instance, the following has the same
effect as enabling the option:
openssl_conf = openssl_init
[openssl_init]
providers = providers
[providers]
default = activate
legacy = activate
[activate]
activate = yes
Determined by whether the library provides curves for it or not.
For instance, in the OpenSSL 3 FIPS provider the Brainpool curves are
not included. And in the Fedora package several weak curves are
explicitly patched out and the Brainpool curves are omitted even in
non-FIPS mode.
Tobias Brunner