commit 260be63e7dd06056ea05e8e7511d304e1ad7faff
author Gilles Peskine <Gilles.Peskine@arm.com> Wed Mar 31 22:56:43 2021 +0200
committer Ronald Cron <ronald.cron@arm.com> Thu Jun 10 10:40:30 2021 +0200
tree 1188ba372c0281f16fa20189f28799b7e0a83d06
parent c53560ea0054a2441e57bb353fd83d886869edf8

dhm_check_range: microoptimization

No need to build a bignum for the value 2.

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

library/dhm.c

diff --git a/library/dhm.c b/library/dhm.c
index 4624659..7eb52b0 100644
--- a/library/dhm.c
+++ b/library/dhm.c
@@ -130,22 +130,21 @@
  */
 static int dhm_check_range( const mbedtls_mpi *param, const mbedtls_mpi *P )
 {
-    mbedtls_mpi L, U;
+    mbedtls_mpi U;
     int ret = 0;
 
-    mbedtls_mpi_init( &L ); mbedtls_mpi_init( &U );
+    mbedtls_mpi_init( &U );
 
-    MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &L, 2 ) );
     MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &U, P, 2 ) );
 
-    if( mbedtls_mpi_cmp_mpi( param, &L ) < 0 ||
+    if( mbedtls_mpi_cmp_int( param, 2 ) < 0 ||
         mbedtls_mpi_cmp_mpi( param, &U ) > 0 )
     {
         ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA;
     }
 
 cleanup:
-    mbedtls_mpi_free( &L ); mbedtls_mpi_free( &U );
+    mbedtls_mpi_free( &U );
     return( ret );
 }