commit d6adcb61467ee2146f89a0fdc069c47276f278db
author Raef Coles <raef.coles@arm.com> Tue Oct 11 15:34:56 2022 +0100
committer Raef Coles <raef.coles@arm.com> Thu Oct 13 14:29:53 2022 +0100
tree 28ec368e1aac9d8d7136ec4f99a46a8ef5b2dd58
parent 810612e14ec26021f56e065fcdab09600f93fb4e

Add negative LMS import/export tests

Signed-off-by: Raef Coles <raef.coles@arm.com>

tests/suites/test_suite_lms.data

diff --git a/tests/suites/test_suite_lms.data b/tests/suites/test_suite_lms.data
index 5dd9019..5acf69c 100644
--- a/tests/suites/test_suite_lms.data
+++ b/tests/suites/test_suite_lms.data
@@ -179,5 +179,9 @@
 LMS import/export test
 # This test uses a randomly generated LMS public key. It imports the key, and
 # then exports it, and verifies that the exported key is identical to the
-# original key.
-lms_import_export_test:"00000006000000046B0927585C8547228D495361D73B970C287A2254BF8F1B170E55ACC9520A56CE5D2C711B6617718B49247D28CCC6D11D"
+# original key. It also tests handling of too-small key export buffers.
+lms_import_export_test:"0000000600000004d96bb26744d99ef624e32161c36d3d6efcdd0484e2b17a6dd183125be4b1af1cda931a91a3acb1151877c174f7943fd9":0
+
+LMS import/export negative test #1
+# This test uses the randomly generated LMS public key 
+lms_import_export_test:"0000000600000004d96bb26744d99ef624e32161c36d3d6efcdd0484e2b17a6dd183125be4b1af1cda931a91a3acb1151877c174f7943fd9":0

tests/suites/test_suite_lms.function

diff --git a/tests/suites/test_suite_lms.function b/tests/suites/test_suite_lms.function
index 7ba02c5..860304e 100644
--- a/tests/suites/test_suite_lms.function
+++ b/tests/suites/test_suite_lms.function
@@ -149,18 +149,40 @@
 /* END_CASE */
 
 /* BEGIN_CASE */
-void lms_import_export_test (  data_t * pub_key )
+void lms_import_export_test (  data_t * pub_key, int expected_import_rc )
 {
     mbedtls_lms_public_t ctx;
-    uint8_t exported_pub_key[MBEDTLS_LMS_PUBLIC_KEY_LEN(MBEDTLS_LMS_SHA256_M32_H10)];
+    size_t exported_pub_key_buf_size = 0;
+    size_t exported_pub_key_size = 0;
+    unsigned char *exported_pub_key = NULL;
 
     mbedtls_lms_public_init(&ctx);
     TEST_EQUAL( mbedtls_lms_import_public_key( &ctx, pub_key->x, pub_key->len ), 0 );
-    TEST_EQUAL( mbedtls_lms_export_public_key( &ctx, exported_pub_key,
-                                                sizeof(exported_pub_key), NULL ), 0 );
 
-    ASSERT_COMPARE( pub_key->x, MBEDTLS_LMS_PUBLIC_KEY_LEN(MBEDTLS_LMS_SHA256_M32_H10),
-                    exported_pub_key, MBEDTLS_LMS_PUBLIC_KEY_LEN(MBEDTLS_LMS_SHA256_M32_H10) );
+    if( expected_import_rc == 0 )
+    {
+        exported_pub_key_buf_size = MBEDTLS_LMS_PUBLIC_KEY_LEN(MBEDTLS_LMS_SHA256_M32_H10);
+        ASSERT_ALLOC( exported_pub_key, exported_pub_key_buf_size );
+
+        TEST_EQUAL( mbedtls_lms_export_public_key( &ctx, exported_pub_key,
+                                                   exported_pub_key_buf_size,
+                                                   &exported_pub_key_size ), 0 );
+
+        TEST_EQUAL( exported_pub_key_buf_size, exported_pub_key_size );
+        ASSERT_COMPARE( pub_key->x, MBEDTLS_LMS_PUBLIC_KEY_LEN(MBEDTLS_LMS_SHA256_M32_H10),
+                        exported_pub_key, MBEDTLS_LMS_PUBLIC_KEY_LEN(MBEDTLS_LMS_SHA256_M32_H10) );
+        mbedtls_free(exported_pub_key);
+        exported_pub_key = NULL;
+
+        /* Export into too-small buffer should fail */
+        exported_pub_key_buf_size = MBEDTLS_LMS_PUBLIC_KEY_LEN(MBEDTLS_LMS_SHA256_M32_H10) - 1;
+        ASSERT_ALLOC( exported_pub_key, exported_pub_key_buf_size);
+        TEST_EQUAL( mbedtls_lms_export_public_key( &ctx, exported_pub_key,
+                                                   exported_pub_key_buf_size, NULL ),
+                    MBEDTLS_ERR_LMS_BUFFER_TOO_SMALL );
+        mbedtls_free(exported_pub_key);
+        exported_pub_key = NULL;
+    }
 
 exit:
     mbedtls_lms_public_free( &ctx );