New function mbedtls_ecjpake_set_point_format

Use this instead of accessing the field directly.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

ChangeLog.d/ecjpake-point_format.txt

@@ -0,0 +1,4 @@
+Features
+   * Use the new function mbedtls_ecjpake_set_point_format() to select the
+     point format for ECJPAKE instead of accessing the point_format field
+     directly, which is no longer supported.

include/mbedtls/ecjpake.h

@@ -131,6 +131,21 @@ int mbedtls_ecjpake_setup( mbedtls_ecjpake_context *ctx,
                            const unsigned char *secret,
                            size_t len );
 
+/**
+ * \brief               Set the point format for future reads and writes.
+ *
+ * \param ctx           The ECJPAKE context to configure.
+ * \param point_format  The point format to use:
+ *                      #MBEDTLS_ECP_PF_UNCOMPRESSED (default)
+ *                      or #MBEDTLS_ECP_PF_COMPRESSED.
+ *
+ * \return              \c 0 if successful.
+ * \return              #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if \p point_format
+ *                      is invalid.
+ */
+int mbedtls_ecjpake_set_point_format( mbedtls_ecjpake_context *ctx,
+                                      int point_format );
+
 /**
  * \brief           Check if an ECJPAKE context is ready for use.
  *

library/ecjpake.c

@@ -128,6 +128,20 @@ cleanup:
     return( ret );
 }
 
+int mbedtls_ecjpake_set_point_format( mbedtls_ecjpake_context *ctx,
+                                      int point_format )
+{
+    switch( point_format )
+    {
+        case MBEDTLS_ECP_PF_UNCOMPRESSED:
+        case MBEDTLS_ECP_PF_COMPRESSED:
+            ctx->point_format = point_format;
+            return( 0 );
+        default:
+            return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+    }
+}
+
 /*
  * Check if context is ready for use
  */

library/ssl_cli.c

@@ -1663,7 +1663,8 @@ static int ssl_parse_supported_point_formats_ext( mbedtls_ssl_context *ssl,
             ssl->handshake->ecdh_ctx.point_format = p[0];
 #endif
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-            ssl->handshake->ecjpake_ctx.point_format = p[0];
+            mbedtls_ecjpake_set_point_format( &ssl->handshake->ecjpake_ctx,
+                                              p[0] );
 #endif
             MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) );
             return( 0 );

library/ssl_srv.c

@@ -407,7 +407,8 @@ static int ssl_parse_supported_point_formats( mbedtls_ssl_context *ssl,
             ssl->handshake->ecdh_ctx.point_format = p[0];
 #endif
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-            ssl->handshake->ecjpake_ctx.point_format = p[0];
+            mbedtls_ecjpake_set_point_format( &ssl->handshake->ecjpake_ctx,
+                                              p[0] );
 #endif
             MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) );
             return( 0 );