Add initial test driver conforming to the new spec

Also adjusted the different makefiles accordingly.
Note: driver lifetime is currently statically defined in the header, but
this will be replaced in the future based on autogeneration of lifetime
values by a script (TBD)

Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
diff --git a/tests/src/drivers/signature.c b/tests/src/drivers/signature.c
new file mode 100644
index 0000000..0f006c7
--- /dev/null
+++ b/tests/src/drivers/signature.c
@@ -0,0 +1,171 @@
+/*
+ * Test driver for signature functions
+ */
+/*  Copyright (C) 2020, ARM Limited, All Rights Reserved
+ *  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.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_PSA_CRYPTO_DRIVERS) && defined(MBEDTLS_TEST_HOOKS)
+#include "psa/crypto.h"
+#include "mbedtls/ecp.h"
+
+#include "drivers/signature.h"
+
+#include "mbedtls/md.h"
+#include "mbedtls/ecdsa.h"
+
+#include <string.h>
+
+/* If non-null, on success, copy this to the output. */
+void *test_driver_forced_output = NULL;
+size_t test_driver_forced_output_length = 0;
+
+psa_status_t test_transparent_signature_sign_hash_status = PSA_ERROR_NOT_SUPPORTED;
+unsigned long test_transparent_signature_sign_hash_hit = 0;
+
+psa_status_t test_transparent_signature_sign_hash(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key, size_t key_length,
+    psa_algorithm_t alg,
+    const uint8_t *hash, size_t hash_length,
+    uint8_t *signature, size_t signature_size, size_t *signature_length )
+{
+    ++test_transparent_signature_sign_hash_hit;
+
+    if( test_transparent_signature_sign_hash_status != PSA_SUCCESS )
+        return( test_transparent_signature_sign_hash_status );
+
+    if( test_driver_forced_output != NULL )
+    {
+        if( test_driver_forced_output_length > signature_size )
+            return( PSA_ERROR_BUFFER_TOO_SMALL );
+        memcpy( signature, test_driver_forced_output,
+                test_driver_forced_output_length );
+        *signature_length = test_driver_forced_output_length;
+        return( PSA_SUCCESS );
+    }
+
+    psa_status_t status = PSA_ERROR_NOT_SUPPORTED;
+
+#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECDSA_DETERMINISTIC) && \
+    defined(MBEDTLS_SHA256_C)
+    if( alg != PSA_ALG_DETERMINISTIC_ECDSA( PSA_ALG_SHA_256 ) )
+        return( PSA_ERROR_NOT_SUPPORTED );
+    mbedtls_ecp_group_id grp_id;
+    switch( psa_get_key_type( attributes ) )
+    {
+        case PSA_ECC_CURVE_SECP_R1:
+            switch( psa_get_key_bits( attributes ) )
+            {
+                case 256:
+                    grp_id = MBEDTLS_ECP_DP_SECP256R1;
+                    break;
+                case 384:
+                    grp_id = MBEDTLS_ECP_DP_SECP384R1;
+                    break;
+                case 521:
+                    grp_id = MBEDTLS_ECP_DP_SECP521R1;
+                    break;
+                default:
+                    return( PSA_ERROR_NOT_SUPPORTED );
+            }
+            break;
+        default:
+            return( PSA_ERROR_NOT_SUPPORTED );
+    }
+
+    /* Beyond this point, the driver is actually doing the work of
+     * calculating the signature. */
+
+    status = PSA_ERROR_GENERIC_ERROR;
+    int ret = 0;
+    mbedtls_mpi r, s;
+    mbedtls_mpi_init( &r );
+    mbedtls_mpi_init( &s );
+    mbedtls_ecp_keypair ecp;
+    mbedtls_ecp_keypair_init( &ecp );
+    size_t curve_bytes = PSA_BITS_TO_BYTES( ecp.grp.pbits );
+
+    MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &ecp.grp, grp_id ) );
+    MBEDTLS_MPI_CHK( mbedtls_ecp_point_read_binary( &ecp.grp, &ecp.Q,
+                                                    key, key_length ) );
+
+    /* Code adapted from psa_ecdsa_sign() in psa_crypto.c. */
+    mbedtls_md_type_t md_alg = MBEDTLS_MD_SHA256;
+    if( signature_size < 2 * curve_bytes )
+    {
+        status = PSA_ERROR_BUFFER_TOO_SMALL;
+        goto cleanup;
+    }
+    MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign_det( &ecp.grp, &r, &s, &ecp.d,
+                                  hash, hash_length, md_alg ) );
+    MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &r,
+                                               signature,
+                                               curve_bytes ) );
+    MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &s,
+                                               signature + curve_bytes,
+                                               curve_bytes ) );
+cleanup:
+    /* There's no easy way to translate the error code except through a
+     * library function that's not exported. Use a debugger. */
+    if( ret == 0 )
+        status = PSA_SUCCESS;
+    mbedtls_mpi_free( &r );
+    mbedtls_mpi_free( &s );
+    mbedtls_ecp_keypair_free( &ecp );
+    if( status == PSA_SUCCESS )
+        *signature_length = 2 * curve_bytes;
+#else /* defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECDSA_DETERMINISTIC) && \
+         defined(MBEDTLS_SHA256_C) */
+    (void) attributes;
+    (void) key;
+    (void) key_length;
+    (void) alg;
+    (void) hash;
+    (void) hash_length;
+#endif /* defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECDSA_DETERMINISTIC) && \
+          defined(MBEDTLS_SHA256_C) */
+
+    return( status );
+}
+
+psa_status_t test_opaque_signature_sign_hash(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key, size_t key_length,
+    psa_algorithm_t alg,
+    const uint8_t *hash, size_t hash_length,
+    uint8_t *signature, size_t signature_size, size_t *signature_length )
+{
+    (void) attributes;
+    (void) key;
+    (void) key_length;
+    (void) alg;
+    (void) hash;
+    (void) hash_length;
+    (void) signature;
+    (void) signature_size;
+    (void) signature_length;
+    return( PSA_ERROR_NOT_SUPPORTED );
+}
+
+#endif /* MBEDTLS_PSA_CRYPTO_DRIVERS && MBEDTLS_TEST_HOOKS */