This commit adds helper functions to ssl_tls13_keys.[ch]
allowing to derive the secrets specific to each stage of
a TLS 1.3 handshake (early, handshake, application) from
the corresponding master secret (early secret, handshake
secret, master secret).
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
ssl_tls1_3_keys.c exports a structure containing all labels used
in the TLS 1.3 key schedule, but the TLS 1.3 key scheduling unit
tests so far replicated those labels in the test file. In particular,
wrong label values in ssl_tls1_3_keys.c wouldn't have been caught
by the unit tests.
This commit modifies the TLS 1.3 key schedule unit tests to use
the TLS 1.3 labels as exported by ssl_tls1_3_keys.c. This not only
makes sure that those labels are correct, but also avoids hardcoding
their hex-encoding in the test file.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
This commit introduces a new file library/ssl_tls13_key.c
which will subsequently be populated with functionality relating
to the TLS 1.3 key schedule.
Those functions are expected to be internal and are documented
in the internal header library/ssl_tls13_keys.h.
The first function to be implemented is the key expansion
function `HKDF-Expand-Label`. See the documentation in
library/ssl_tls13_keys.h for more information.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
