Address various issues

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ecdh.c b/library/ecdh.c
index 27e5d73..ddd4ef5 100644
--- a/library/ecdh.c
+++ b/library/ecdh.c
@@ -808,24 +808,21 @@
 
 static int ecdh_tls13_read_public_internal( mbedtls_ecdh_context_mbed *ctx,
                                             const unsigned char *buf,
-                                            size_t blen )
+                                            size_t buf_len )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     const unsigned char *p = buf;
     size_t data_len;
 
-    if( blen < 3 )
+    if( buf_len < 3 )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
 
     data_len = MBEDTLS_GET_UINT16_BE( p, 0 );
     p += 2;
 
-    if( data_len < 1 || data_len != ( blen - 2 ) )
+    if( data_len < 1 || data_len != ( buf_len - 2 ) )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
 
-    /*
-     * Save buffer start for read_binary and update buf
-     */
     if( ( ret = mbedtls_ecp_point_read_binary( &ctx->grp,
                                                &ctx->Qp, p, data_len ) ) != 0)
     {
@@ -840,13 +837,13 @@
  */
 int mbedtls_ecdh_tls13_read_public( mbedtls_ecdh_context *ctx,
                                     const unsigned char *buf,
-                                    size_t blen )
+                                    size_t buf_len )
 {
     ECDH_VALIDATE_RET( ctx != NULL );
     ECDH_VALIDATE_RET( buf != NULL );
 
 #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
-    return( ecdh_tls13_read_public_internal( ctx, buf, blen ) );
+    return( ecdh_tls13_read_public_internal( ctx, buf, buf_len ) );
 #else
     switch( ctx->var )
     {
@@ -856,7 +853,7 @@
 #endif
         case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
             return( ecdh_tls13_read_public_internal( &ctx->ctx.mbed_ecdh,
-                                                     buf, blen ) );
+                                                     buf, buf_len ) );
         default:
             return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }