Move bignum helpers to their own module
Move bignum-related helper functions to their own files under tests/include
and tests/src. The primary motivation is that a subsequent commit will make
bignum_helpers.h include library/bignum*.h, but we want to be able to
include <test/helpers.h> without having the library directory on the include
path (we do this in some programs under programs/ intended for testing).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/src/bignum_helpers.c b/tests/src/bignum_helpers.c
new file mode 100644
index 0000000..575bd03
--- /dev/null
+++ b/tests/src/bignum_helpers.c
@@ -0,0 +1,119 @@
+/**
+ * \file bignum_helpers.c
+ *
+ * \brief This file contains the prototypes of helper functions for
+ * bignum-related testing.
+ */
+
+/*
+ * Copyright The Mbed TLS Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define MBEDTLS_ALLOW_PRIVATE_ACCESS
+#include <test/bignum_helpers.h>
+
+#if defined(MBEDTLS_BIGNUM_C)
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <mbedtls/bignum.h>
+#include <bignum_core.h>
+#include <bignum_mod.h>
+#include <bignum_mod_raw.h>
+
+#include <test/helpers.h>
+#include <test/macros.h>
+
+int mbedtls_test_read_mpi_core( mbedtls_mpi_uint **pX, size_t *plimbs,
+ const char *input )
+{
+ /* Sanity check */
+ if( *pX != NULL )
+ return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+
+ size_t hex_len = strlen( input );
+ size_t byte_len = ( hex_len + 1 ) / 2;
+ *plimbs = CHARS_TO_LIMBS( byte_len );
+
+ /* A core bignum is not allowed to be empty. Forbid it as test data,
+ * this way static analyzers have a chance of knowing we don't expect
+ * the bignum functions to support empty inputs. */
+ if( *plimbs == 0 )
+ return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+
+ *pX = mbedtls_calloc( *plimbs, sizeof( **pX ) );
+ if( *pX == NULL )
+ return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
+
+ unsigned char *byte_start = ( unsigned char * ) *pX;
+ if( byte_len % sizeof( mbedtls_mpi_uint ) != 0 )
+ {
+ byte_start += sizeof( mbedtls_mpi_uint ) - byte_len % sizeof( mbedtls_mpi_uint );
+ }
+ if( ( hex_len & 1 ) != 0 )
+ {
+ /* mbedtls_test_unhexify wants an even number of hex digits */
+ TEST_ASSERT( mbedtls_test_ascii2uc( *input, byte_start ) == 0 );
+ ++byte_start;
+ ++input;
+ --byte_len;
+ }
+ TEST_ASSERT( mbedtls_test_unhexify( byte_start,
+ byte_len,
+ input,
+ &byte_len ) == 0 );
+
+ mbedtls_mpi_core_bigendian_to_host( *pX, *plimbs );
+ return( 0 );
+
+exit:
+ mbedtls_free( *pX );
+ return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+}
+
+int mbedtls_test_read_mpi( mbedtls_mpi *X, const char *s )
+{
+ int negative = 0;
+ /* Always set the sign bit to -1 if the input has a minus sign, even for 0.
+ * This creates an invalid representation, which mbedtls_mpi_read_string()
+ * avoids but we want to be able to create that in test data. */
+ if( s[0] == '-' )
+ {
+ ++s;
+ negative = 1;
+ }
+ /* mbedtls_mpi_read_string() currently retains leading zeros.
+ * It always allocates at least one limb for the value 0. */
+ if( s[0] == 0 )
+ {
+ mbedtls_mpi_free( X );
+ return( 0 );
+ }
+ int ret = mbedtls_mpi_read_string( X, 16, s );
+ if( ret != 0 )
+ return( ret );
+ if( negative )
+ {
+ if( mbedtls_mpi_cmp_int( X, 0 ) == 0 )
+ ++mbedtls_test_case_uses_negative_0;
+ X->s = -1;
+ }
+ return( 0 );
+}
+
+#endif /* MBEDTLS_BIGNUM_C */
+