All existing cipher suites use SHA-256 as the TLSv1.2 and above
handshake digest algorithm (even when using SHA-1 as the MAC digest
algorithm). Some GCM cipher suites use SHA-384 as the handshake
digest algorithm.
Allow the cipher suite to specify the handshake (and PRF) digest
algorithm to be used for TLSv1.2 and above.
This requires some restructuring to allow for the fact that the
ClientHello message must be included within the handshake digest, even
though the relevant digest algorithm is not yet known at the point
that the ClientHello is sent. Fortunately, the ClientHello may be
reproduced verbatim at the point of receiving the ServerHello, so we
rely on reconstructing (rather than storing) this message.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
TLS stream and block ciphers use a MAC with a length equal to the
output length of the digest algorithm in use. For AEAD ciphers there
is no MAC, with the equivalent functionality provided by the cipher
algorithm's authentication tag.
Allow for the existence of AEAD cipher suites by making the MAC length
a parameter of the cipher suite.
Assume that the MAC key length is equal to the MAC length, since this
is true for all currently supported cipher suites.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
TLS block ciphers always use CBC (as per RFC 5246 section 6.2.3.2)
with a record initialisation vector length that is equal to the cipher
block size, and no fixed initialisation vector.
The initialisation vector for AEAD ciphers such as GCM is less
straightforward, and requires both a fixed and per-record component.
Extend the definition of a cipher suite to include fixed and record
initialisation vector lengths, and generate the fixed portion (if any)
as part of key expansion.
Do not add explicit calls to cipher_setiv() in tls_assemble_block()
and tls_split_block(), since the constraints imposed by RFC 5246 are
specifically chosen to allow implementations to avoid doing so.
(Instead, add a sanity check that the record initialisation vector
length is equal to the cipher block size.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add support for SHA-224, SHA-384, and SHA-512 as digest algorithms in
X.509 certificates, and allow the choice of public-key, cipher, and
digest algorithms to be configured at build time via config/crypto.h.
Originally-implemented-by: Tufan Karadere <tufank@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown