Add driver wrapper function for raw key agreement, along with test call for transparent drivers.

Signed-off-by: Aditya Deshpande <aditya.deshpande@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 2ce5e43..194d986 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -5793,26 +5793,28 @@
 
 #define PSA_KEY_AGREEMENT_MAX_SHARED_SECRET_SIZE MBEDTLS_ECP_MAX_BYTES
 
-static psa_status_t psa_key_agreement_raw_internal( psa_algorithm_t alg,
-                                                    psa_key_slot_t *private_key,
-                                                    const uint8_t *peer_key,
-                                                    size_t peer_key_length,
-                                                    uint8_t *shared_secret,
-                                                    size_t shared_secret_size,
-                                                    size_t *shared_secret_length )
+psa_status_t psa_key_agreement_raw_builtin( const psa_key_attributes_t *attributes,
+                                            const uint8_t *key_buffer,
+                                            size_t key_buffer_size,
+                                            psa_algorithm_t alg,
+                                            const uint8_t *peer_key,
+                                            size_t peer_key_length,
+                                            uint8_t *shared_secret,
+                                            size_t shared_secret_size,
+                                            size_t *shared_secret_length )
 {
     switch( alg )
     {
 #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH)
         case PSA_ALG_ECDH:
-            if( ! PSA_KEY_TYPE_IS_ECC_KEY_PAIR( private_key->attr.type ) )
+            if( ! PSA_KEY_TYPE_IS_ECC_KEY_PAIR( attributes->core.type ) )
                 return( PSA_ERROR_INVALID_ARGUMENT );
             mbedtls_ecp_keypair *ecp = NULL;
             psa_status_t status = mbedtls_psa_ecp_load_representation(
-                                      private_key->attr.type,
-                                      private_key->attr.bits,
-                                      private_key->key.data,
-                                      private_key->key.bytes,
+                                      attributes->core.type,
+                                      attributes->core.bits,
+                                      key_buffer,
+                                      key_buffer_size,
                                       &ecp );
             if( status != PSA_SUCCESS )
                 return( status );
@@ -5825,7 +5827,9 @@
             return( status );
 #endif /* MBEDTLS_PSA_BUILTIN_ALG_ECDH */
         default:
-            (void) private_key;
+            (void) attributes;
+            (void) key_buffer;
+            (void) key_buffer_size;
             (void) peer_key;
             (void) peer_key_length;
             (void) shared_secret;
@@ -5835,6 +5839,34 @@
     }
 }
 
+/** Internal function for raw key agreement
+ *  Calls the driver wrapper which will hand off key agreement task
+ *  to the driver's implementation if a driver is present. 
+ *  Fallback specified in the driver wrapper is built-in raw key agreement 
+ *  (psa_key_agreement_raw_builtin).
+ */
+static psa_status_t psa_key_agreement_raw_internal( psa_algorithm_t alg,
+                                                    psa_key_slot_t *private_key,
+                                                    const uint8_t *peer_key,
+                                                    size_t peer_key_length,
+                                                    uint8_t *shared_secret,
+                                                    size_t shared_secret_size,
+                                                    size_t *shared_secret_length )
+{
+    if( !PSA_ALG_IS_RAW_KEY_AGREEMENT(alg) )
+        return( PSA_ERROR_NOT_SUPPORTED );
+
+    psa_key_attributes_t attributes = {
+      .core = private_key->attr
+    };
+
+    return( psa_driver_wrapper_key_agreement( &attributes, private_key->key.data,
+                                                  private_key->key.bytes, 
+                                                  alg, peer_key, peer_key_length, 
+                                                  shared_secret, shared_secret_size, 
+                                                  shared_secret_length ) );
+}
+
 /* Note that if this function fails, you must call psa_key_derivation_abort()
  * to potentially free embedded data structures and wipe confidential data.
  */
diff --git a/library/psa_crypto_core.h b/library/psa_crypto_core.h
index 8c91b04..5bfdfb3 100644
--- a/library/psa_crypto_core.h
+++ b/library/psa_crypto_core.h
@@ -547,4 +547,62 @@
  */
 psa_status_t psa_validate_unstructured_key_bit_size( psa_key_type_t type,
                                                      size_t bits );
+
+/** Perform a key agreement and return the raw shared secret, using 
+    built-in raw key agreement functions.
+ *
+ * \note The signature of this function is that of a PSA driver
+ *       key_agreement entry point. This function behaves as a key_agreement
+ *       entry point as defined in the PSA driver interface specification for
+ *       transparent drivers.
+ *
+ * \param[in]  attributes               The attributes of the key to use for
+ *                                      the operation.
+ * \param[in]  key_buffer               The buffer containing the private key
+ *                                      context.
+ * \param[in]  key_buffer_size          Size of the \p key_buffer buffer in
+ *                                      bytes.
+ * \param[in]  alg                      A key agreement algorithm that is
+ *                                      compatible with the type of the key.
+ * \param[in]  peer_key                 The buffer containing the key context
+ *                                      of the peer's public key.
+ * \param[in]  peer_key_length          Size of the \p peer_key buffer in 
+ *                                      bytes.
+ * \param[out] shared_secret            The buffer to which the shared secret
+ *                                      is to be written.
+ * \param[in]  shared_secret_size       Size of the \p shared_secret buffer in
+ *                                      bytes.
+ * \param[out] shared_secret_length     On success, the number of bytes that
+ *                                      make up the returned shared secret.
+ * \retval #PSA_SUCCESS
+ *         Success. Shared secret successfully calculated.
+ * \retval #PSA_ERROR_INVALID_HANDLE
+ * \retval #PSA_ERROR_NOT_PERMITTED
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ *         \p alg is not a key agreement algorithm, or
+ *         \p private_key is not compatible with \p alg,
+ *         or \p peer_key is not valid for \p alg or not compatible with
+ *         \p private_key.
+ * \retval #PSA_ERROR_BUFFER_TOO_SMALL
+ *         \p shared_secret_size is too small
+ * \retval #PSA_ERROR_NOT_SUPPORTED
+ *         \p alg is not a supported key agreement algorithm.
+ * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
+ * \retval #PSA_ERROR_COMMUNICATION_FAILURE
+ * \retval #PSA_ERROR_HARDWARE_FAILURE
+ * \retval #PSA_ERROR_CORRUPTION_DETECTED
+ * \retval #PSA_ERROR_STORAGE_FAILURE
+ * \retval #PSA_ERROR_BAD_STATE
+ */
+psa_status_t psa_key_agreement_raw_builtin( 
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer,
+    size_t key_buffer_size,
+    psa_algorithm_t alg,
+    const uint8_t *peer_key,
+    size_t peer_key_length,
+    uint8_t *shared_secret,
+    size_t shared_secret_size,
+    size_t *shared_secret_length );
+                   
 #endif /* PSA_CRYPTO_CORE_H */
diff --git a/library/psa_crypto_driver_wrappers.h b/library/psa_crypto_driver_wrappers.h
index ee23b6f..017a4b6 100644
--- a/library/psa_crypto_driver_wrappers.h
+++ b/library/psa_crypto_driver_wrappers.h
@@ -357,6 +357,22 @@
     size_t output_size,
     size_t *output_length );
 
+/*
+ * Raw Key Agreement
+ */
+
+ psa_status_t psa_driver_wrapper_key_agreement(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer,
+    size_t key_buffer_size,
+    psa_algorithm_t alg,
+    const uint8_t *peer_key,
+    size_t peer_key_length,
+    uint8_t *shared_secret,
+    size_t shared_secret_size,
+    size_t *shared_secret_length
+ );
+
 #endif /* PSA_CRYPTO_DRIVER_WRAPPERS_H */
 
 /* End of automatically generated file. */