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.
OpenSSL enforces a minimum of 14 bytes (112 bits) on the key size when
used in FIPS-mode (as required by SP 800-131A). So by using an empty
string, instantiation always failed. 32 bytes (256 bits) should be safe
for now.
Closesstrongswan/strongswan#557
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.
If we pass a pointer to NULL, the memory allocated by OpenSSL has to be
freed with OPENSSL_free(). Otherwise, this can lead to random
crashes/freezes for Windows builds as seen on AppVeyor. To not
complicate things for callers of this macro, we allocate our own memory,
which we already do for other i2d_* calls.
If no valid key is configured (e.g. because it's inadvertently uninitialized),
we should not just reuse the previous key.
The `key_set` flag is not necessary anymore because a non-NULL key is set
during initialization since 6b347d5232 ("openssl: Ensure underlying hash
algorithm is available during HMAC init").
Apparently, we should use OPENSSL_free() to release memory allocated by
OpenSSL. While it generally maps to free() that's apparently not the
case on Windows, where the ECP test vectors caused `ACCESS_VIOLATION
exception` crashes (not always the same vector).
Fixes: 74e02ff5e6 ("openssl: Mainly use EVP interface for ECDH")
Functions like ECDH_compute_key() will be removed with OpenSSL 3 (which
will require additional changes as other functions will be deprecated or
removed too).
ECDH_compute_key() was not used because it only gives x-coordinate of
the result. However, the default setting, as per the errata mentioned,
is to use x-coordinate only.
Use ECDH_compute_key() for this setting as it additionally allows HW
offload of the computation using dynamic engine feature in OpenSSL.
EC_POINT_mul() doesn't allow HW offload.
Signed-off-by: Mahantesh Salimath <[email protected]>
The x509 plugin accepted CRL signers since forever, to be precise, since
dffb176f2b ("CRLSign keyUsage or CA basicConstraint are sufficient
for CRL validation")).
References #3529.
OpenSSL currently doesn't support squeezing bytes out of an XOF multiple
times. Unfortunately, EVP_DigestFinalXOF() completely resets the context
and later calls not simply fail, they cause a null-pointer dereference in
libcrypto. This fixes the crash at the cost of repeating initializing
the whole state and allocating too much data for subsequent calls.
There is an open issue and PR that might add a function that allows
squeezing more data from an XOF in a future version of OpenSSL.
Doing this for the self-signed check also (i.e. if this and issuer are
the same) is particularly useful if the issuer uses a different key type.
Otherwise, we'd try to verify the signature with an incompatible key
that would result in a log message.
Fixes#3357.
Without this we only would learn that the algorithm isn't actually
available (e.g. due to FIPS mode) when set_key() is called later, so there
isn't any automatic fallback to other implementations.
Fixes#3284.
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.
Tobias Brunner