Add check for changing arguments
In case of argument change, freeing everything is not the most efficient (wastes one free()+calloc()) but makes the code simpler, which is probably more important here
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2 changed files with 28 additions and 3 deletions
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@ -105,6 +105,8 @@ void mbedtls_ecp_set_max_ops( unsigned max_ops )
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*/
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struct mbedtls_ecp_restart {
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unsigned char fake_it; /* for tests: should we fake early return? */
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mbedtls_mpi m; /* saved argument: scalar */
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mbedtls_ecp_point P; /* saved argument: point */
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};
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/*
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@ -122,6 +124,9 @@ static void ecp_restart_free( mbedtls_ecp_restart_ctx *ctx )
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{
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if( ctx == NULL )
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return;
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mbedtls_mpi_free( &ctx->m );
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mbedtls_ecp_point_free( &ctx->P );
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}
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#endif /* MBEDTLS_ECP_EARLY_RETURN */
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@ -1514,22 +1519,35 @@ static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
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size_t d;
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mbedtls_ecp_point *T = NULL;
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/* set up restart context if needed */
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#if defined(MBEDTLS_ECP_EARLY_RETURN)
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/* check for restart with new arguments */
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if( grp->rs != NULL &&
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( mbedtls_mpi_cmp_mpi( m, &grp->rs->m ) != 0 ||
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mbedtls_mpi_cmp_mpi( &P->X, &grp->rs->P.X ) != 0 ||
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mbedtls_mpi_cmp_mpi( &P->Y, &grp->rs->P.Y ) != 0 ) )
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{
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ecp_restart_free( grp->rs );
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mbedtls_free( grp->rs );
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grp->rs = NULL;
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}
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/* set up restart context if needed */
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if( ecp_max_ops != 0 && grp->rs == NULL )
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{
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grp->rs = mbedtls_calloc( 1, sizeof( mbedtls_ecp_restart_ctx ) );
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if( grp->rs == NULL )
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return( MBEDTLS_ERR_ECP_ALLOC_FAILED );
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ecp_restart_init( grp->rs );
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grp->rs->fake_it = 1;
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MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &grp->rs->m, m ) );
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MBEDTLS_MPI_CHK( mbedtls_ecp_copy( &grp->rs->P, P ) );
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}
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#endif
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/* XXX: temporary */
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#if defined(MBEDTLS_ECP_EARLY_RETURN)
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if( grp->rs && grp->rs->fake_it++ != 0 )
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if( grp->rs && ++grp->rs->fake_it != 0 )
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return( MBEDTLS_ERR_ECP_IN_PROGRESS );
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#endif
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@ -121,6 +121,13 @@ void ecp_test_vect_restart( int id,
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}
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while( ret != 0 );
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/* Ok, now start an operation with some arguments, and drop it.
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* We'll see if the result of the next operation, with different args,
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* are correct regardless (do we discard old context on new args?).
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* This also tests that we don't write to R prematurely */
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ret = mbedtls_ecp_mul( &grp, &R, &dA, &grp.G, NULL, NULL );
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TEST_ASSERT( ret == 0 || ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
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/* Non-base point case */
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cnt_restarts = 0;
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do {
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