tests/suites/test_suite_bignum_mod.function

/* BEGIN_HEADER */
#include "mbedtls/bignum.h"
#include "mbedtls/entropy.h"
#include "bignum_mod.h"
#include "constant_time_internal.h"
#include "test/constant_flow.h"
/* END_HEADER */

/* BEGIN_DEPENDENCIES
 * depends_on:MBEDTLS_BIGNUM_C
 * END_DEPENDENCIES
 */

/* BEGIN_CASE */
void mpi_mod_setup( int ext_rep, int int_rep, int iret )
{
    #define MLIMBS 8
    mbedtls_mpi_uint mp[MLIMBS];
    mbedtls_mpi_mod_modulus m;
    const size_t mp_size = sizeof(mbedtls_mpi_uint);
    mbedtls_mpi_uint * rr;
    int ret;

    memset( mp, 0xFF, mp_size );

    mbedtls_mpi_mod_modulus_init( &m );
    ret = mbedtls_mpi_mod_modulus_setup( &m, mp, MLIMBS, ext_rep, int_rep );
    TEST_EQUAL( ret, iret );

    /* Only test if the constants have been set-up  */
    if ( ret == 0 && int_rep == MBEDTLS_MPI_MOD_REP_MONTGOMERY )
    {
        /* Test that the consts have been calculated */
        TEST_ASSERT( m.rep.mont.rr != NULL );
        TEST_ASSERT( m.rep.mont.mm != 0 );

        /* Keep a copy of the memory location used to store Montgomery const */
        rr = (mbedtls_mpi_uint *)m.rep.mont.rr;
    }

    /* Address sanitiser should catch if we try to free mp */
    mbedtls_mpi_mod_modulus_free( &m );

    /* Make sure that the modulus doesn't have reference to mp anymore */
    TEST_ASSERT( m.p != mp );

    /* Only test if the constants have been set-up  */
    if ( ret == 0 && int_rep == MBEDTLS_MPI_MOD_REP_MONTGOMERY )
    {
        /* Reuse the allocated buffer for a zeroization check */
        memset( mp, 0x00, mp_size );

        /* Verify the data and pointers allocated have been properly wiped */
        TEST_ASSERT( m.rep.mont.rr == NULL );
        TEST_ASSERT( m.rep.mont.mm == 0 );

        /* mbedtls_mpi_mod_modulus_free() has set the
         * (mbedtls_mpi_uint *)m.rep.mont.rr -> NULL.
         * Verify that the actual data have been zeroed */
        ASSERT_COMPARE( rr, mp_size, &mp, mp_size );
    }
exit:
    /* It should be safe to call an mbedtls free several times */
    mbedtls_mpi_mod_modulus_free( &m );

    #undef MLIMBS
}
/* END_CASE */