yuzu/mbedtls
1
0
Fork 0
mirror of https://github.com/yuzu-emu/mbedtls.git synced 2025-03-24 22:25:11 +00:00
Code Issues Packages Projects Releases Wiki Activity

Save some small memory allocations inside ecp_mul()

Browse source
This commit is contained in:
Manuel Pégourié-Gonnard 2013-12-30 16:04:55 +01:00
parent fe40f484fb
commit 72c172a13d
1 changed files with 5 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
library/ecp.c
View file

@ -915,6 +915,8 @@ cleanup:
* due to the choice of precomputed points in the modified comb method. * due to the choice of precomputed points in the modified comb method.
* So branches for these cases do not leak secret information. * So branches for these cases do not leak secret information.
* *
* We accept Q->Z being unset (saving memory in tables) as meaning 1.
*
* Cost: 1A := 8M + 3S * Cost: 1A := 8M + 3S
*/ */
static int ecp_add_mixed( const ecp_group *grp, ecp_point *R, static int ecp_add_mixed( const ecp_group *grp, ecp_point *R,
@ -933,13 +935,13 @@ static int ecp_add_mixed( const ecp_group *grp, ecp_point *R,
if( mpi_cmp_int( &P->Z, 0 ) == 0 ) if( mpi_cmp_int( &P->Z, 0 ) == 0 )
return( ecp_copy( R, Q ) ); return( ecp_copy( R, Q ) );
if( mpi_cmp_int( &Q->Z, 0 ) == 0 ) if( Q->Z.p != NULL && mpi_cmp_int( &Q->Z, 0 ) == 0 )
return( ecp_copy( R, P ) ); return( ecp_copy( R, P ) );
/* /*
* Make sure Q coordinates are normalized * Make sure Q coordinates are normalized
*/ */
if( mpi_cmp_int( &Q->Z, 1 ) != 0 ) if( Q->Z.p != NULL && mpi_cmp_int( &Q->Z, 1 ) != 0 )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA ); return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
mpi_init( &T1 ); mpi_init( &T2 ); mpi_init( &T3 ); mpi_init( &T4 ); mpi_init( &T1 ); mpi_init( &T2 ); mpi_init( &T3 ); mpi_init( &T4 );
@ -1240,9 +1242,6 @@ static int ecp_select_comb( const ecp_group *grp, ecp_point *R,
MPI_CHK( mpi_safe_cond_assign( &R->Y, &T[j].Y, j == ii ) ); MPI_CHK( mpi_safe_cond_assign( &R->Y, &T[j].Y, j == ii ) );
} }
/* The Z coordinate is always 1 */
MPI_CHK( mpi_lset( &R->Z, 1 ) );
/* Safely invert result if i is "negative" */ /* Safely invert result if i is "negative" */
MPI_CHK( ecp_safe_invert_jac( grp, R, i >> 7 ) ); MPI_CHK( ecp_safe_invert_jac( grp, R, i >> 7 ) );
@ -1271,6 +1270,7 @@ static int ecp_mul_comb_core( const ecp_group *grp, ecp_point *R,
/* Start with a non-zero point and randomize its coordinates */ /* Start with a non-zero point and randomize its coordinates */
i = d; i = d;
MPI_CHK( ecp_select_comb( grp, R, T, t_len, x[i] ) ); MPI_CHK( ecp_select_comb( grp, R, T, t_len, x[i] ) );
MPI_CHK( mpi_lset( &R->Z, 1 ) );
if( f_rng != 0 ) if( f_rng != 0 )
MPI_CHK( ecp_randomize_jac( grp, R, f_rng, p_rng ) ); MPI_CHK( ecp_randomize_jac( grp, R, f_rng, p_rng ) );