From 185ccf7070f4d4d555eba161d30332dde3b61a28 Mon Sep 17 00:00:00 2001
From: Paul Bakker <paul.bakker@arm.com>
Date: Thu, 14 Jul 2016 13:21:10 +0100
Subject: [PATCH] Add coverage for CTR-DRBG corner case function behaviours

---
 tests/suites/test_suite_ctr_drbg.data     |  3 +++
 tests/suites/test_suite_ctr_drbg.function | 28 +++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/tests/suites/test_suite_ctr_drbg.data b/tests/suites/test_suite_ctr_drbg.data
index 5c69d20cb..666165851 100644
--- a/tests/suites/test_suite_ctr_drbg.data
+++ b/tests/suites/test_suite_ctr_drbg.data
@@ -727,6 +727,9 @@ ctr_drbg_seed_file:"data_files/ctr_drbg_seed":0
 CTR_DRBG write/update seed file
 ctr_drbg_seed_file:"no_such_dir/file":MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR
 
+CTR_DRBG Special Behaviours
+ctr_drbg_special_behaviours:
+
 CTR_DRBG self test
 ctr_drbg_selftest:
 
diff --git a/tests/suites/test_suite_ctr_drbg.function b/tests/suites/test_suite_ctr_drbg.function
index b7d2bece9..3c7873b31 100644
--- a/tests/suites/test_suite_ctr_drbg.function
+++ b/tests/suites/test_suite_ctr_drbg.function
@@ -16,6 +16,34 @@ int mbedtls_entropy_func( void *data, unsigned char *buf, size_t len )
  * END_DEPENDENCIES
  */
 
+/* BEGIN_CASE */
+void ctr_drbg_special_behaviours( )
+{
+    mbedtls_ctr_drbg_context ctx;
+    unsigned char output[512];
+    unsigned char additional[512];
+
+    mbedtls_ctr_drbg_init( &ctx );
+    memset( output, 0, sizeof( output ) );
+    memset( additional, 0, sizeof( additional ) );
+
+    TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx,
+                        output, MBEDTLS_CTR_DRBG_MAX_REQUEST + 1,
+                        additional, 16 ) ==
+                        MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG );
+    TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx,
+                        output, 16,
+                        additional, MBEDTLS_CTR_DRBG_MAX_INPUT + 1 ) ==
+                        MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
+
+    TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, additional,
+                        MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + 1 ) ==
+                        MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
+exit:
+    mbedtls_ctr_drbg_free( &ctx );
+}
+/* END_CASE */
+
 /* BEGIN_CASE */
 void ctr_drbg_validate_pr( char *add_init_string, char *entropy_string,
                            char *add1_string, char *add2_string,