Merge pull request #5545 from xffbai/tls13-write-enc-ext
TLS1.3: add writing encrypted extensions on server side.
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index d024abf..59e42c8 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -1189,8 +1189,6 @@
static int ssl_tls13_postprocess_server_hello( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
- mbedtls_ssl_key_set traffic_keys;
- mbedtls_ssl_transform *transform_handshake = NULL;
mbedtls_ssl_handshake_params *handshake = ssl->handshake;
/* Determine the key exchange mode:
@@ -1234,50 +1232,21 @@
ret = mbedtls_ssl_tls13_key_schedule_stage_early( ssl );
if( ret != 0 )
{
- MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_key_schedule_stage_early_data",
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_key_schedule_stage_early",
ret );
goto cleanup;
}
- /* Compute handshake secret */
- ret = mbedtls_ssl_tls13_key_schedule_stage_handshake( ssl );
+ ret = mbedtls_ssl_tls13_compute_handshake_transform( ssl );
if( ret != 0 )
{
- MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_derive_master_secret", ret );
- goto cleanup;
- }
-
- /* Next evolution in key schedule: Establish handshake secret and
- * key material. */
- ret = mbedtls_ssl_tls13_generate_handshake_keys( ssl, &traffic_keys );
- if( ret != 0 )
- {
- MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_generate_handshake_keys",
+ MBEDTLS_SSL_DEBUG_RET( 1,
+ "mbedtls_ssl_tls13_compute_handshake_transform",
ret );
goto cleanup;
}
- transform_handshake = mbedtls_calloc( 1, sizeof( mbedtls_ssl_transform ) );
- if( transform_handshake == NULL )
- {
- ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
- goto cleanup;
- }
-
- ret = mbedtls_ssl_tls13_populate_transform( transform_handshake,
- ssl->conf->endpoint,
- ssl->session_negotiate->ciphersuite,
- &traffic_keys,
- ssl );
- if( ret != 0 )
- {
- MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_populate_transform", ret );
- goto cleanup;
- }
-
- handshake->transform_handshake = transform_handshake;
- mbedtls_ssl_set_inbound_transform( ssl, transform_handshake );
-
+ mbedtls_ssl_set_inbound_transform( ssl, handshake->transform_handshake );
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Switch to handshake keys for inbound traffic" ) );
ssl->session_in = ssl->session_negotiate;
@@ -1287,16 +1256,13 @@
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS );
cleanup:
-
- mbedtls_platform_zeroize( &traffic_keys, sizeof( traffic_keys ) );
if( ret != 0 )
{
- mbedtls_free( transform_handshake );
-
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE,
MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
+
return( ret );
}
diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index 6559bc9..8ffd9a1 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -27,6 +27,7 @@
#include "mbedtls/hkdf.h"
#include "mbedtls/debug.h"
#include "mbedtls/error.h"
+#include "mbedtls/platform.h"
#include "ssl_misc.h"
#include "ssl_tls13_keys.h"
@@ -1506,8 +1507,62 @@
/* randbytes is not used again */
mbedtls_platform_zeroize( ssl->handshake->randbytes,
sizeof( ssl->handshake->randbytes ) );
+
mbedtls_platform_zeroize( transcript, sizeof( transcript ) );
return( ret );
}
+int mbedtls_ssl_tls13_compute_handshake_transform( mbedtls_ssl_context *ssl )
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+ mbedtls_ssl_key_set traffic_keys;
+ mbedtls_ssl_transform *transform_handshake = NULL;
+ mbedtls_ssl_handshake_params *handshake = ssl->handshake;
+
+ /* Compute handshake secret */
+ ret = mbedtls_ssl_tls13_key_schedule_stage_handshake( ssl );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_derive_master_secret", ret );
+ goto cleanup;
+ }
+
+ /* Next evolution in key schedule: Establish handshake secret and
+ * key material. */
+ ret = mbedtls_ssl_tls13_generate_handshake_keys( ssl, &traffic_keys );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_generate_handshake_keys",
+ ret );
+ goto cleanup;
+ }
+
+ transform_handshake = mbedtls_calloc( 1, sizeof( mbedtls_ssl_transform ) );
+ if( transform_handshake == NULL )
+ {
+ ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
+ goto cleanup;
+ }
+
+ ret = mbedtls_ssl_tls13_populate_transform(
+ transform_handshake,
+ ssl->conf->endpoint,
+ ssl->session_negotiate->ciphersuite,
+ &traffic_keys,
+ ssl );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_populate_transform", ret );
+ goto cleanup;
+ }
+ handshake->transform_handshake = transform_handshake;
+
+cleanup:
+ mbedtls_platform_zeroize( &traffic_keys, sizeof( traffic_keys ) );
+ if( ret != 0 )
+ mbedtls_free( transform_handshake );
+
+ return( ret );
+}
+
#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
diff --git a/library/ssl_tls13_keys.h b/library/ssl_tls13_keys.h
index d56067c..676ebae 100644
--- a/library/ssl_tls13_keys.h
+++ b/library/ssl_tls13_keys.h
@@ -638,6 +638,17 @@
size_t *actual_len,
int which );
+/**
+ * \brief Compute TLS 1.3 handshake transform
+ *
+ * \param ssl The SSL context to operate on. The early secret must have been
+ * computed.
+ *
+ * \returns \c 0 on success.
+ * \returns A negative error code on failure.
+ */
+int mbedtls_ssl_tls13_compute_handshake_transform( mbedtls_ssl_context *ssl );
+
#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
#endif /* MBEDTLS_SSL_TLS1_3_KEYS_H */
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index d06b9a8..b2a5cfc 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -22,10 +22,8 @@
#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_PROTO_TLS1_3)
#include "mbedtls/debug.h"
-
-#include "ssl_misc.h"
-#include "ssl_tls13_keys.h"
-#include "ssl_debug_helpers.h"
+#include "mbedtls/error.h"
+#include "mbedtls/platform.h"
#if defined(MBEDTLS_ECP_C)
#include "mbedtls/ecp.h"
@@ -39,6 +37,10 @@
#define mbedtls_free free
#endif /* MBEDTLS_PLATFORM_C */
+#include "ssl_misc.h"
+#include "ssl_tls13_keys.h"
+#include "ssl_debug_helpers.h"
+
/* From RFC 8446:
* struct {
* ProtocolVersion versions<2..254>;
@@ -1024,6 +1026,26 @@
return( ret );
}
+static int ssl_tls13_finalize_write_server_hello( mbedtls_ssl_context *ssl )
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+ ret = mbedtls_ssl_tls13_compute_handshake_transform( ssl );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1,
+ "mbedtls_ssl_tls13_compute_handshake_transform",
+ ret );
+ return( ret );
+ }
+
+ mbedtls_ssl_set_outbound_transform( ssl,
+ ssl->handshake->transform_handshake );
+ MBEDTLS_SSL_DEBUG_MSG(
+ 3, ( "switching to handshake transform for outbound data" ) );
+
+ return( ret );
+}
+
static int ssl_tls13_write_server_hello( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -1047,7 +1069,10 @@
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg(
ssl, buf_len, msg_len ) );
+ MBEDTLS_SSL_PROC_CHK( ssl_tls13_finalize_write_server_hello( ssl ) );
+
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS );
+
cleanup:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
@@ -1055,6 +1080,78 @@
}
/*
+ * Handler for MBEDTLS_SSL_ENCRYPTED_EXTENSIONS
+ */
+
+/*
+ * struct {
+ * Extension extensions<0..2 ^ 16 - 1>;
+ * } EncryptedExtensions;
+ *
+ */
+static int ssl_tls13_write_encrypted_extensions_body( mbedtls_ssl_context *ssl,
+ unsigned char *buf,
+ unsigned char *end,
+ size_t *out_len )
+{
+ unsigned char *p = buf;
+ size_t extensions_len = 0;
+ unsigned char *p_extensions_len;
+
+ *out_len = 0;
+
+ MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
+ p_extensions_len = p;
+ p += 2;
+
+ ((void) ssl);
+
+ extensions_len = ( p - p_extensions_len ) - 2;
+ MBEDTLS_PUT_UINT16_BE( extensions_len, p_extensions_len, 0 );
+
+ *out_len = p - buf;
+
+ MBEDTLS_SSL_DEBUG_BUF( 4, "encrypted extensions", buf, *out_len );
+
+ return( 0 );
+}
+
+static int ssl_tls13_write_encrypted_extensions( mbedtls_ssl_context *ssl )
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+ unsigned char *buf;
+ size_t buf_len, msg_len;
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write encrypted extensions" ) );
+
+ MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( ssl,
+ MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, &buf, &buf_len ) );
+
+ MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_encrypted_extensions_body(
+ ssl, buf, buf + buf_len, &msg_len ) );
+
+ mbedtls_ssl_add_hs_msg_to_checksum(
+ ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, buf, msg_len );
+
+ MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg(
+ ssl, buf_len, msg_len ) );
+
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+ if( mbedtls_ssl_tls13_some_psk_enabled( ssl ) )
+ mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED );
+ else
+ mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_CERTIFICATE );
+#else
+ mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED );
+#endif
+
+cleanup:
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write encrypted extensions" ) );
+ return( ret );
+}
+
+/*
* TLS 1.3 State Machine -- server side
*/
int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
@@ -1089,6 +1186,15 @@
ret = ssl_tls13_write_server_hello( ssl );
break;
+ case MBEDTLS_SSL_ENCRYPTED_EXTENSIONS:
+ ret = ssl_tls13_write_encrypted_extensions( ssl );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_encrypted_extensions", ret );
+ return( ret );
+ }
+ break;
+
default:
MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index dcee5df..07ad1b3 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -11307,6 +11307,7 @@
-s "tls13 server state: MBEDTLS_SSL_CLIENT_HELLO" \
-s "tls13 server state: MBEDTLS_SSL_SERVER_HELLO" \
-s "tls13 server state: MBEDTLS_SSL_ENCRYPTED_EXTENSIONS" \
+ -s "tls13 server state: MBEDTLS_SSL_SERVER_CERTIFICATE" \
-s "SSL - The requested feature is not available" \
-s "=> parse client hello" \
-s "<= parse client hello"
@@ -11323,6 +11324,7 @@
-s "tls13 server state: MBEDTLS_SSL_CLIENT_HELLO" \
-s "tls13 server state: MBEDTLS_SSL_SERVER_HELLO" \
-s "tls13 server state: MBEDTLS_SSL_ENCRYPTED_EXTENSIONS" \
+ -s "tls13 server state: MBEDTLS_SSL_SERVER_CERTIFICATE" \
-s "SSL - The requested feature is not available" \
-s "=> parse client hello" \
-s "<= parse client hello"
@@ -11338,7 +11340,8 @@
-s "tls13 server state: MBEDTLS_SSL_CLIENT_HELLO" \
-s "tls13 server state: MBEDTLS_SSL_SERVER_HELLO" \
-s "tls13 server state: MBEDTLS_SSL_ENCRYPTED_EXTENSIONS" \
- -c "client state: MBEDTLS_SSL_ENCRYPTED_EXTENSIONS" \
+ -s "tls13 server state: MBEDTLS_SSL_SERVER_CERTIFICATE" \
+ -c "client state: MBEDTLS_SSL_CERTIFICATE_REQUEST" \
-s "SSL - The requested feature is not available" \
-s "=> parse client hello" \
-s "<= parse client hello"