The old API has been deprecated with OpenSSL 3 and direct access to the
state isn't possible via EVP API. In the future we might just remove this
implementation but we'd probably have to implement EAP-AKA' first, which
uses HMAC-SHA-256 with IKEv2's prf+ construct to derive keys instead
of this weird construct (plus what fips-prf builds around it) that's used
by EAP-AKA.
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.
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
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.
Using the workaround with the EVP interface, which we use to derive shared
keys since 74e02ff5e6 ("openssl: Mainly use EVP interface for ECDH"),
would actually require us to register the OIDs of these curves as NID.
Otherwise, the two EC_GROUPs used by private and public key objects
are not considered the same and the key derivation fails.
Since the curves are supported by OpenSSL since 1.0.2 it's probably rare to
find a version without them nowadays. One exception is the old BoringSSL
version we still use on Android, which defines the NIDs but not the curve
data. However, that version also lacks support to register OIDs as NIDs,
so the only option to support these groups there would be to got back to not
using the EVP interface, which isn't in anyone's interest. If there really
is a need for them there, we could probably patch BoringSSL or use OpenSSL.
While CCM is available in earlier versions, we only use it with
OpenSSL 1.1.0 and newer because the generic control variables are not
available before and we default to GCM for them.
Closesstrongswan/strongswan#353.
According to the documentation, it's generally not necessary to manually
seed OpenSSL's DRBG (and it actually can cause the daemon to lock up
during start up on systems with low entropy if OpenSSL is already trying
to seed it itself and holds the lock). While that might already have been
the case with earlier versions, it's not explicitly stated in their
documentation. So we keep the code for these versions.
The functional reference created by ENGINE_init() was never released,
only the structural one created by ENGINE_by_id(). The functional
reference includes an implicit structural reference, which is also
released by ENGINE_finish().
Closesstrongswan/strongswan#119.
While X25519 was already added with 1.1.0a, its use would be a lot more
complicated, as the helpers like EVP_PKEY_new_raw_public_key() were only
added in 1.1.1, which also added X448.
We can't call OPENSSL_cleanup() as that would prevent us from
re-initializing the library again (which we use in the Android app, that
loads/unloads plugins).
The default ESP cipher suite is now
AES_CBC-128/HMAC_SHA2_256_128
and requires SHA-2 HMAC support in the Linux kernel (correctly implemented
since 2.6.33).
The default IKE cipher suite is now
AES_CBC-128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_256
if the openssl plugin is loaded or
AES_CBC-128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_3072
if ECC is not available.
The use of the SHA-1 hash algorithm and the MODP_2048 DH group has been
deprecated and ENCR_CHACHA20_POLY1305 has been added to the default
IKE AEAD algorithms.
To use SSL in curl, we need to initialize the SSL library in a thread-safe
manner and provide the appropriate callbacks. As we already do that in our
crypto plugins using these libraries, we depend on these features.
This implies that we need the same plugin enabled (openssl, gcrypt) as the
curl backend is configured to use to fetch from HTTPS URIs.
If FIPS mode has been enabled by other means, under some environments it can't
be entered again. It fails with "FIPS mode already set". To avoid it, we first
check the mode before changing it.
Enabling FIPS mode twice will fail, so if it is enabled in openssl.conf
it should be disabled in strongswan.conf (or the other way around).
Either way, we should log whether FIPS mode is enabled or not.
References #412.
Tobias Brunner