tree 57a750061d7423dd65eda930f2314b2bf6dcbe8e
parent 5c7336ce889e267163d970f11e034e65c1c30624
author Harald Welte <laforge@osmocom.org> 1685436937 +0200
committer laforge <laforge@osmocom.org> 1685694595 +0000

libosmogsm: Support authentication with 256-bit K and/or OP/OPc

3GPP TS 33.102 Section 6.3.7 states that K can be 128 or 256 bits,
while our 'struct osmo_sub_auth_data' had a fixed-size 128bit field.

This means we cannot use our auth_core for algorithms with larger
key sizes, such as TUAK.  Let's introduce osmo_sub_auth_data2 for
larger (and variable) sized K and OP[c].

K and OP[c] can even have different sizes in TUAK, where OP[c] is
always 256bit, but K can be 128 or 256 bits.  So we need separate
length fields for K and OP[c].

I'm adding backwards-compatibility API wrappers, so old applications
just continue to work as they always did.

However, I'm not adding compatibility wrappers for the plug-in API
that can be used to register additional authentication implementations
at runtime.  We don't know of any user of that API outside of
libosmocore, so the function signatures of the 'struct osmo_auth_impl'
are modified in an incompatible way.

Change-Id: Ie775fedba4a3fa12314c0f7c8a369662ef6a40df