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Adjust ECP self-test to support Curve448

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Adjust the Montgomery self-test to use Curve448 in builds without
Curve25519.

Signed-off-by: Gilles Peskine <gilles.peskine@arm.com>
This commit is contained in:
Gilles Peskine 2018-09-17 18:31:15 +02:00
parent 24666795e4
commit a088c81fcb
1 changed files with 36 additions and 0 deletions
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36
library/ecp.c
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@ -3292,6 +3292,39 @@ cleanup:
#if defined(MBEDTLS_SELF_TEST)
static int self_test_adjust_exponent( const mbedtls_ecp_group *grp,
mbedtls_mpi *m )
{
int ret = 0;
switch( grp->id )
{
/* If Curve25519 is available, then that's what we use for the
* Montgomery test, so we don't need the adjustment code. */
#if ! defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
#if defined(MBEDTLS_ECP_DP_CURVE448_ENABLED)
case MBEDTLS_ECP_DP_CURVE448:
/* Move highest bit from 254 to N-1. Setting bit N-1 is
* necessary to enforce the highest-bit-set constraint. */
MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( m, 254, 0 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( m, grp->nbits, 1 ) );
/* Copy second-highest bit from 253 to N-2. This is not
* necessary but improves the test variety a bit. */
MBEDTLS_MPI_CHK(
mbedtls_mpi_set_bit( m, grp->nbits - 1,
mbedtls_mpi_get_bit( m, 253 ) ) );
break;
#endif
#endif /* ! defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) */
default:
/* Non-Montgomery curves and Curve25519 need no adjustment. */
(void) grp;
(void) m;
goto cleanup;
}
cleanup:
return( ret );
}
static int self_test_point( int verbose,
mbedtls_ecp_group *grp,
mbedtls_ecp_point *R,
@ -3306,7 +3339,9 @@ static int self_test_point( int verbose,
add_count = 0;
dbl_count = 0;
mul_count = 0;
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( m, 16, exponents[0] ) );
MBEDTLS_MPI_CHK( self_test_adjust_exponent( grp, m ) );
MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, NULL, NULL ) );
for( i = 1; i < n_exponents; i++ )
@ -3319,6 +3354,7 @@ static int self_test_point( int verbose,
mul_count = 0;
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( m, 16, exponents[i] ) );
MBEDTLS_MPI_CHK( self_test_adjust_exponent( grp, m ) );
MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, NULL, NULL ) );
if( add_count != add_c_prev ||