diff --git a/library/dhm.c b/library/dhm.c index d652cf0ac9..85840c31d8 100644 --- a/library/dhm.c +++ b/library/dhm.c @@ -180,21 +180,11 @@ int mbedtls_dhm_read_params( mbedtls_dhm_context *ctx, return( 0 ); } -/* - * Setup and write the ServerKeyExchange parameters - */ -int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size, - unsigned char *output, size_t *olen, - int (*f_rng)(void *, unsigned char *, size_t), - void *p_rng ) +static int dhm_make_common( mbedtls_dhm_context *ctx, int x_size, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng ) { int ret, count = 0; - size_t n1, n2, n3; - unsigned char *p; - DHM_VALIDATE_RET( ctx != NULL ); - DHM_VALIDATE_RET( output != NULL ); - DHM_VALIDATE_RET( olen != NULL ); - DHM_VALIDATE_RET( f_rng != NULL ); if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 ) return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); @@ -223,6 +213,30 @@ int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size, if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 ) return( ret ); +cleanup: + return( ret ); +} + +/* + * Setup and write the ServerKeyExchange parameters + */ +int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size, + unsigned char *output, size_t *olen, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng ) +{ + int ret; + size_t n1, n2, n3; + unsigned char *p; + DHM_VALIDATE_RET( ctx != NULL ); + DHM_VALIDATE_RET( output != NULL ); + DHM_VALIDATE_RET( olen != NULL ); + DHM_VALIDATE_RET( f_rng != NULL ); + + ret = dhm_make_common( ctx, x_size, f_rng, p_rng ); + if( ret != 0 ) + goto cleanup; + /* * export P, G, GX */ @@ -250,11 +264,9 @@ int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size, ctx->len = n1; cleanup: - - if( ret != 0 ) + if( ret != 0 && ret > -128 ) return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED + ret ); - - return( 0 ); + return( ret ); } /* @@ -306,7 +318,7 @@ int mbedtls_dhm_make_public( mbedtls_dhm_context *ctx, int x_size, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) { - int ret, count = 0; + int ret; DHM_VALIDATE_RET( ctx != NULL ); DHM_VALIDATE_RET( output != NULL ); DHM_VALIDATE_RET( f_rng != NULL ); @@ -314,38 +326,19 @@ int mbedtls_dhm_make_public( mbedtls_dhm_context *ctx, int x_size, if( olen < 1 || olen > ctx->len ) return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); - if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 ) - return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); - - /* - * generate X and calculate GX = G^X mod P - */ - do - { - MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) ); - - while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 ) - MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) ); - - if( count++ > 10 ) - return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED ); - } - while( dhm_check_range( &ctx->X, &ctx->P ) != 0 ); - - MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X, - &ctx->P , &ctx->RP ) ); - - if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 ) - return( ret ); + ret = dhm_make_common( ctx, x_size, f_rng, p_rng ); + if( ret == MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED ) + return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED ); + if( ret != 0 ) + goto cleanup; MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->GX, output, olen ) ); cleanup: - - if( ret != 0 ) + if( ret != 0 && ret > -128 ) return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED + ret ); - return( 0 ); + return( ret ); } /*