commit 0dbf04a9a6f3f362187a99e472a9cb5958832ab1
author Hanno Becker <hanno.becker@arm.com> Wed Apr 13 06:54:48 2022 +0100
committer Hanno Becker <hanno.becker@arm.com> Wed Apr 13 07:26:53 2022 +0100
tree 2da7e2bbea93531df390204ab84e4bfea2a7d010
parent 1772e05fca942dde3cd5a87346746fc77ec68e59

Remove unnecessary memory operations in p25519 quasireduction

Signed-off-by: Hanno Becker <hanno.becker@arm.com>

library/ecp_curves.c

diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index 5788b0d..6b8ff5c 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -5229,13 +5229,12 @@
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
 
     /* Split N as N + 2^256 M */
-    memset( Mp,   0,    sizeof( Mp ) );
     memcpy( Mp,   NT_p, sizeof( mbedtls_mpi_uint ) * NT_n );
     memset( NT_p, 0,    sizeof( mbedtls_mpi_uint ) * NT_n );
 
     /* N = A0 + 38 * A1 */
-    mbedtls_mpi_core_mla( N->p, N->n,
-                          Mp, P255_WIDTH,
+    mbedtls_mpi_core_mla( N->p, P255_WIDTH + 1,
+                          Mp, NT_n,
                           38 );
 
     return( 0 );