From 8b356b5652ddf4570e175fca343fe22532ac95dc Mon Sep 17 00:00:00 2001
From: Gilles Peskine <Gilles.Peskine@arm.com>
Date: Tue, 25 Aug 2020 23:44:59 +0200
Subject: [PATCH] Test other output sizes for psa_mac_sign_finish

Test psa_mac_sign_finish with a smaller or larger buffer.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
---
 tests/suites/test_suite_psa_crypto.function | 46 +++++++++++++++------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 5b0054d64..4b70115cc 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -3032,6 +3032,13 @@ void mac_sign( int key_type_arg,
     size_t mac_buffer_size =
         PSA_MAC_FINAL_SIZE( key_type, PSA_BYTES_TO_BITS( key->len ), alg );
     size_t mac_length = 0;
+    const size_t output_sizes_to_test[] = {
+        0,
+        1,
+        expected_mac->len - 1,
+        expected_mac->len,
+        expected_mac->len + 1,
+    };
 
     TEST_ASSERT( mac_buffer_size <= PSA_MAC_MAX_SIZE );
     /* We expect PSA_MAC_FINAL_SIZE to be exact. */
@@ -3045,20 +3052,35 @@ void mac_sign( int key_type_arg,
 
     PSA_ASSERT( psa_import_key( &attributes, key->x, key->len, &handle ) );
 
-    ASSERT_ALLOC( actual_mac, mac_buffer_size );
+    for( size_t i = 0; i < ARRAY_LENGTH( output_sizes_to_test ); i++ )
+    {
+        const size_t output_size = output_sizes_to_test[i];
+        psa_status_t expected_status =
+            ( output_size >= expected_mac->len ? PSA_SUCCESS :
+              PSA_ERROR_BUFFER_TOO_SMALL );
 
-    /* Calculate the MAC. */
-    PSA_ASSERT( psa_mac_sign_setup( &operation,
-                                    handle, alg ) );
-    PSA_ASSERT( psa_mac_update( &operation,
-                                input->x, input->len ) );
-    PSA_ASSERT( psa_mac_sign_finish( &operation,
-                                     actual_mac, mac_buffer_size,
-                                     &mac_length ) );
+        test_set_step( output_size );
+        ASSERT_ALLOC( actual_mac, output_size );
 
-    /* Compare with the expected value. */
-    ASSERT_COMPARE( expected_mac->x, expected_mac->len,
-                    actual_mac, mac_length );
+        /* Calculate the MAC. */
+        PSA_ASSERT( psa_mac_sign_setup( &operation,
+                                        handle, alg ) );
+        PSA_ASSERT( psa_mac_update( &operation,
+                                    input->x, input->len ) );
+        TEST_EQUAL( psa_mac_sign_finish( &operation,
+                                         actual_mac, output_size,
+                                         &mac_length ),
+                    expected_status );
+        PSA_ASSERT( psa_mac_abort( &operation ) );
+
+        if( expected_status == PSA_SUCCESS )
+        {
+            ASSERT_COMPARE( expected_mac->x, expected_mac->len,
+                            actual_mac, mac_length );
+        }
+        mbedtls_free( actual_mac );
+        actual_mac = NULL;
+    }
 
 exit:
     psa_destroy_key( handle );