tls13: add generate handshake keys
Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 5afdc4c..d9759af 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -478,6 +478,27 @@
};
typedef struct mbedtls_ssl_key_set mbedtls_ssl_key_set;
+typedef struct
+{
+ unsigned char binder_key [ MBEDTLS_MD_MAX_SIZE ];
+ unsigned char client_early_traffic_secret [ MBEDTLS_MD_MAX_SIZE ];
+ unsigned char early_exporter_master_secret[ MBEDTLS_MD_MAX_SIZE ];
+} mbedtls_ssl_tls1_3_early_secrets;
+
+typedef struct
+{
+ unsigned char client_handshake_traffic_secret[ MBEDTLS_MD_MAX_SIZE ];
+ unsigned char server_handshake_traffic_secret[ MBEDTLS_MD_MAX_SIZE ];
+} mbedtls_ssl_tls1_3_handshake_secrets;
+
+typedef struct
+{
+ unsigned char client_application_traffic_secret_N[ MBEDTLS_MD_MAX_SIZE ];
+ unsigned char server_application_traffic_secret_N[ MBEDTLS_MD_MAX_SIZE ];
+ unsigned char exporter_master_secret [ MBEDTLS_MD_MAX_SIZE ];
+ unsigned char resumption_master_secret [ MBEDTLS_MD_MAX_SIZE ];
+} mbedtls_ssl_tls1_3_application_secrets;
+
/*
* This structure contains the parameters only needed during handshake.
*/
@@ -682,6 +703,8 @@
unsigned char handshake[MBEDTLS_MD_MAX_SIZE];
unsigned char app [MBEDTLS_MD_MAX_SIZE];
} tls13_master_secrets;
+
+ mbedtls_ssl_tls1_3_handshake_secrets tls13_hs_secrets;
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index b7beb12..5435a25 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -847,4 +847,120 @@
return( 0 );
}
+/* mbedtls_ssl_tls13_generate_handshake_keys() generates keys necessary for
+ * protecting the handshake messages, as described in Section 7 of TLS 1.3. */
+int mbedtls_ssl_tls13_generate_handshake_keys( mbedtls_ssl_context *ssl,
+ mbedtls_ssl_key_set *traffic_keys )
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+ mbedtls_md_type_t md_type;
+ mbedtls_md_info_t const *md_info;
+ size_t md_size;
+
+ unsigned char transcript[MBEDTLS_MD_MAX_SIZE];
+ size_t transcript_len;
+
+ mbedtls_cipher_info_t const *cipher_info;
+ size_t keylen, ivlen;
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_tls13_generate_handshake_keys" ) );
+
+ cipher_info = mbedtls_cipher_info_from_type(
+ ssl->handshake->ciphersuite_info->cipher );
+ keylen = cipher_info->key_bitlen >> 3;
+ ivlen = cipher_info->iv_size;
+
+ md_type = ssl->handshake->ciphersuite_info->mac;
+ md_info = mbedtls_md_info_from_type( md_type );
+ md_size = mbedtls_md_get_size( md_info );
+
+ ret = mbedtls_ssl_tls13_get_handshake_transcript( ssl, md_type,
+ transcript,
+ sizeof( transcript ),
+ &transcript_len );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1,
+ "mbedtls_ssl_tls13_get_handshake_transcript",
+ ret );
+ return( ret );
+ }
+
+ ret = mbedtls_ssl_tls1_3_derive_handshake_secrets( md_type,
+ ssl->handshake->tls13_master_secrets.handshake,
+ transcript, transcript_len,
+ &ssl->handshake->tls13_hs_secrets );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls1_3_derive_early_secrets", ret );
+ return( ret );
+ }
+
+ MBEDTLS_SSL_DEBUG_BUF( 4, "Client handshake traffic secret",
+ ssl->handshake->tls13_hs_secrets.client_handshake_traffic_secret,
+ md_size );
+
+ MBEDTLS_SSL_DEBUG_BUF( 4, "Server handshake traffic secret",
+ ssl->handshake->tls13_hs_secrets.server_handshake_traffic_secret,
+ md_size );
+
+ /*
+ * Export client handshake traffic secret
+ */
+#if defined(MBEDTLS_SSL_EXPORT_KEYS)
+ if( ssl->f_export_keys != NULL )
+ {
+ ssl->f_export_keys( ssl->p_export_keys,
+ MBEDTLS_SSL_KEY_EXPORT_TLS13_CLIENT_HANDSHAKE_TRAFFIC_SECRET,
+ ssl->handshake->tls13_hs_secrets.client_handshake_traffic_secret,
+ md_size,
+ ssl->handshake->randbytes + 32,
+ ssl->handshake->randbytes,
+ MBEDTLS_SSL_TLS_PRF_NONE /* TODO: FIX! */ );
+
+ ssl->f_export_keys( ssl->p_export_keys,
+ MBEDTLS_SSL_KEY_EXPORT_TLS13_SERVER_HANDSHAKE_TRAFFIC_SECRET,
+ ssl->handshake->tls13_hs_secrets.server_handshake_traffic_secret,
+ md_size,
+ ssl->handshake->randbytes + 32,
+ ssl->handshake->randbytes,
+ MBEDTLS_SSL_TLS_PRF_NONE /* TODO: FIX! */ );
+ }
+#endif /* MBEDTLS_SSL_EXPORT_KEYS */
+
+ ret = mbedtls_ssl_tls1_3_make_traffic_keys( md_type,
+ ssl->handshake->tls13_hs_secrets.client_handshake_traffic_secret,
+ ssl->handshake->tls13_hs_secrets.server_handshake_traffic_secret,
+ md_size,
+ keylen, ivlen, traffic_keys );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls1_3_make_traffic_keys", ret );
+ goto exit;
+ }
+
+ MBEDTLS_SSL_DEBUG_BUF( 4, "client_handshake write_key",
+ traffic_keys->client_write_key,
+ traffic_keys->key_len);
+
+ MBEDTLS_SSL_DEBUG_BUF( 4, "server_handshake write_key",
+ traffic_keys->server_write_key,
+ traffic_keys->key_len);
+
+ MBEDTLS_SSL_DEBUG_BUF( 4, "client_handshake write_iv",
+ traffic_keys->client_write_iv,
+ traffic_keys->iv_len);
+
+ MBEDTLS_SSL_DEBUG_BUF( 4, "server_handshake write_iv",
+ traffic_keys->server_write_iv,
+ traffic_keys->iv_len);
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_tls13_generate_handshake_keys" ) );
+
+exit:
+
+ return( ret );
+}
+
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
diff --git a/library/ssl_tls13_keys.h b/library/ssl_tls13_keys.h
index 592ba12..7176dee 100644
--- a/library/ssl_tls13_keys.h
+++ b/library/ssl_tls13_keys.h
@@ -70,27 +70,6 @@
#define MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_CONTEXT_LEN \
MBEDTLS_MD_MAX_SIZE
-typedef struct
-{
- unsigned char binder_key [ MBEDTLS_MD_MAX_SIZE ];
- unsigned char client_early_traffic_secret [ MBEDTLS_MD_MAX_SIZE ];
- unsigned char early_exporter_master_secret[ MBEDTLS_MD_MAX_SIZE ];
-} mbedtls_ssl_tls1_3_early_secrets;
-
-typedef struct
-{
- unsigned char client_handshake_traffic_secret[ MBEDTLS_MD_MAX_SIZE ];
- unsigned char server_handshake_traffic_secret[ MBEDTLS_MD_MAX_SIZE ];
-} mbedtls_ssl_tls1_3_handshake_secrets;
-
-typedef struct
-{
- unsigned char client_application_traffic_secret_N[ MBEDTLS_MD_MAX_SIZE ];
- unsigned char server_application_traffic_secret_N[ MBEDTLS_MD_MAX_SIZE ];
- unsigned char exporter_master_secret [ MBEDTLS_MD_MAX_SIZE ];
- unsigned char resumption_master_secret [ MBEDTLS_MD_MAX_SIZE ];
-} mbedtls_ssl_tls1_3_application_secrets;
-
/* Maximum desired length for expanded key material generated
* by HKDF-Expand-Label.
*
@@ -556,4 +535,20 @@
* \returns A negative error code on failure.
*/
int mbedtls_ssl_tls13_key_schedule_stage_early_data( mbedtls_ssl_context *ssl );
+
+/**
+ * \brief Compute TLS 1.3 handshake traffic keys.
+ *
+ * \param ssl The SSL context to operate on. This must be in
+ * key schedule stage \c Handshake, see
+ * mbedtls_ssl_tls13_key_schedule_stage_handshake().
+ * \param traffic_keys The address at which to store the handshake traffic key
+ * keys. This must be writable but may be uninitialized.
+ *
+ * \returns \c 0 on success.
+ * \returns A negative error code on failure.
+ */
+int mbedtls_ssl_tls13_generate_handshake_keys( mbedtls_ssl_context *ssl,
+ mbedtls_ssl_key_set *traffic_keys );
+
#endif /* MBEDTLS_SSL_TLS1_3_KEYS_H */