Add writing CertificateRequest msg on server side
Signed-off-by: Xiaofei Bai <xiaofei.bai@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index b2a5cfc..4e2a0dd 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -25,6 +25,10 @@
#include "mbedtls/error.h"
#include "mbedtls/platform.h"
+#include "ssl_misc.h"
+#include "ssl_tls13_keys.h"
+#include "ssl_debug_helpers.h"
+
#if defined(MBEDTLS_ECP_C)
#include "mbedtls/ecp.h"
#endif /* MBEDTLS_ECP_C */
@@ -729,6 +733,136 @@
return( ret );
}
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+#define SSL_CERTIFICATE_REQUEST_SEND_REQUEST 0
+#define SSL_CERTIFICATE_REQUEST_SKIP 1
+/* Coordination:
+ * Check whether a CertificateRequest message should be written.
+ * Returns a negative code on failure, or
+ * - SSL_CERTIFICATE_REQUEST_SEND_REQUEST
+ * - SSL_CERTIFICATE_REQUEST_SKIP
+ * indicating if the writing of the CertificateRequest
+ * should be skipped or not.
+ */
+static int ssl_tls13_certificate_request_coordinate( mbedtls_ssl_context *ssl )
+{
+ int authmode;
+
+ if( mbedtls_ssl_tls13_some_psk_enabled( ssl ) )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= skip write certificate request" ) );
+ return( SSL_CERTIFICATE_REQUEST_SKIP );
+ }
+#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
+ if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET )
+ authmode = ssl->handshake->sni_authmode;
+ else
+#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
+ authmode = ssl->conf->authmode;
+
+ if( authmode == MBEDTLS_SSL_VERIFY_NONE )
+ return( SSL_CERTIFICATE_REQUEST_SKIP );
+
+ return( SSL_CERTIFICATE_REQUEST_SEND_REQUEST );
+}
+
+/*
+ * struct {
+ * opaque certificate_request_context<0..2^8-1>;
+ * Extension extensions<2..2^16-1>;
+ * } CertificateRequest;
+ *
+ */
+static int ssl_tls13_write_certificate_request( mbedtls_ssl_context *ssl,
+ unsigned char *buf,
+ const unsigned char *end,
+ size_t *out_len )
+{
+ int ret;
+ size_t ext_size = 0;
+ unsigned char *p = buf;
+
+ *out_len = 0;
+
+ /* Check if we have enough space:
+ * - certificate_request_context (1 byte)
+ * - extensions (2 bytes)
+ */
+ MBEDTLS_SSL_CHK_BUF_PTR( p, end, 3 );
+
+ /*
+ * Write certificate_request_context
+ */
+ /*
+ * We use a zero length context for the normal handshake
+ * messages. For post-authentication handshake messages
+ * this request context would be set to a non-zero value.
+ */
+ *p++ = 0x0;
+
+ /*
+ * Write extensions
+ */
+ /* The extensions must contain the signature_algorithms. */
+ ret = mbedtls_ssl_write_sig_alg_ext( ssl, p + 2, end, &ext_size );
+ if( ret != 0 )
+ return( ret );
+
+ /* length field for all extensions */
+ MBEDTLS_PUT_UINT16_BE( ext_size, p, 0 );
+ p += 2 + ext_size;
+
+ *out_len = p - buf;
+
+ return( ret );
+}
+
+static int ssl_tls13_process_certificate_request( mbedtls_ssl_context *ssl )
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
+
+ MBEDTLS_SSL_PROC_CHK_NEG( ssl_tls13_certificate_request_coordinate( ssl ) );
+
+ if( ret == SSL_CERTIFICATE_REQUEST_SEND_REQUEST )
+ {
+ unsigned char *buf;
+ size_t buf_len, msg_len;
+
+ MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_start_handshake_msg( ssl,
+ MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, &buf, &buf_len ) );
+
+ MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_certificate_request(
+ ssl, buf, buf + buf_len, &msg_len ) );
+
+ mbedtls_ssl_tls13_add_hs_msg_to_checksum(
+ ssl, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, buf, msg_len );
+
+ /* TODO: Logically this should come at the end, but the non-MPS msg
+ * layer impl'n of mbedtls_ssl_tls13_finish_handshake_msg() can fail. */
+ MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_finish_handshake_msg(
+ ssl, buf_len, msg_len ) );
+ }
+ else if( ret == SSL_CERTIFICATE_REQUEST_SKIP )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
+ ret = 0;
+ }
+ else
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_CERTIFICATE );
+cleanup:
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
+ return( ret );
+}
+#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+
/*
* Handler for MBEDTLS_SSL_SERVER_HELLO
*/
@@ -1195,6 +1329,12 @@
}
break;
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+ case MBEDTLS_SSL_CERTIFICATE_REQUEST:
+ ret = ssl_tls13_process_certificate_request( ssl );
+ break;
+#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+
default:
MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );