[tls] Allow handshake digest algorithm to be specified by cipher suite

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>

2 files changed, 9 insertions, 0 deletions

diff --git a/src/crypto/mishmash/rsa_aes_cbc_sha1.c b/src/crypto/mishmash/rsa_aes_cbc_sha1.c
index 4f399a036..c2ecf1205 100644
--- a/src/crypto/mishmash/rsa_aes_cbc_sha1.c
+++ b/src/crypto/mishmash/rsa_aes_cbc_sha1.c
@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/rsa.h>
 #include <ipxe/aes.h>
 #include <ipxe/sha1.h>
+#include <ipxe/sha256.h>
 #include <ipxe/tls.h>
 
 /** TLS_DHE_RSA_WITH_AES_128_CBC_SHA cipher suite */
@@ -41,6 +42,7 @@ tls_dhe_rsa_with_aes_128_cbc_sha __tls_cipher_suite ( 03 ) = {
 	.pubkey = &rsa_algorithm,
 	.cipher = &aes_cbc_algorithm,
 	.digest = &sha1_algorithm,
+	.handshake = &sha256_algorithm,
 };
 
 /** TLS_DHE_RSA_WITH_AES_256_CBC_SHA cipher suite */
@@ -55,6 +57,7 @@ tls_dhe_rsa_with_aes_256_cbc_sha __tls_cipher_suite ( 04 ) = {
 	.pubkey = &rsa_algorithm,
 	.cipher = &aes_cbc_algorithm,
 	.digest = &sha1_algorithm,
+	.handshake = &sha256_algorithm,
 };
 
 /** TLS_RSA_WITH_AES_128_CBC_SHA cipher suite */
@@ -69,6 +72,7 @@ tls_rsa_with_aes_128_cbc_sha __tls_cipher_suite ( 13 ) = {
 	.pubkey = &rsa_algorithm,
 	.cipher = &aes_cbc_algorithm,
 	.digest = &sha1_algorithm,
+	.handshake = &sha256_algorithm,
 };
 
 /** TLS_RSA_WITH_AES_256_CBC_SHA cipher suite */
@@ -83,4 +87,5 @@ tls_rsa_with_aes_256_cbc_sha __tls_cipher_suite ( 14 ) = {
 	.pubkey = &rsa_algorithm,
 	.cipher = &aes_cbc_algorithm,
 	.digest = &sha1_algorithm,
+	.handshake = &sha256_algorithm,
 };
diff --git a/src/crypto/mishmash/rsa_aes_cbc_sha256.c b/src/crypto/mishmash/rsa_aes_cbc_sha256.c
index 4b02a7743..7f114b1fd 100644
--- a/src/crypto/mishmash/rsa_aes_cbc_sha256.c
+++ b/src/crypto/mishmash/rsa_aes_cbc_sha256.c
@@ -41,6 +41,7 @@ tls_dhe_rsa_with_aes_128_cbc_sha256 __tls_cipher_suite ( 01 ) = {
 	.pubkey = &rsa_algorithm,
 	.cipher = &aes_cbc_algorithm,
 	.digest = &sha256_algorithm,
+	.handshake = &sha256_algorithm,
 };
 
 /** TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 cipher suite */
@@ -55,6 +56,7 @@ tls_dhe_rsa_with_aes_256_cbc_sha256 __tls_cipher_suite ( 02 ) = {
 	.pubkey = &rsa_algorithm,
 	.cipher = &aes_cbc_algorithm,
 	.digest = &sha256_algorithm,
+	.handshake = &sha256_algorithm,
 };
 
 /** TLS_RSA_WITH_AES_128_CBC_SHA256 cipher suite */
@@ -69,6 +71,7 @@ tls_rsa_with_aes_128_cbc_sha256 __tls_cipher_suite ( 11 ) = {
 	.pubkey = &rsa_algorithm,
 	.cipher = &aes_cbc_algorithm,
 	.digest = &sha256_algorithm,
+	.handshake = &sha256_algorithm,
 };
 
 /** TLS_RSA_WITH_AES_256_CBC_SHA256 cipher suite */
@@ -83,4 +86,5 @@ tls_rsa_with_aes_256_cbc_sha256 __tls_cipher_suite ( 12 ) = {
 	.pubkey = &rsa_algorithm,
 	.cipher = &aes_cbc_algorithm,
 	.digest = &sha256_algorithm,
+	.handshake = &sha256_algorithm,
 };