1 files changed, 50 insertions, 0 deletions
diff --git a/test/tpm_test/trng_test.py b/test/tpm_test/trng_test.py
new file mode 100644
index 0000000000..aac2803076
--- /dev/null
+++ b/test/tpm_test/trng_test.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python2
+# Copyright 2019 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+"""Tests for trng."""
+from __future__ import print_function
+import struct
+
+import subcmd
+import utils
+
+TRNG_TEST_FMT = '>H'
+TRNG_TEST_RSP_FMT = '>H2IH'
+TRNG_TEST_CC = 0x33
+TRNG_SAMPLE_SIZE = 1000 # minimal recommended by NIST is 1000 bytes per sample
+TRNG_SAMPLE_COUNT = 1000 # NIST require at least 1000000 of 8-bit samples
+
+def get_random_command(size):
+  return struct.pack(TRNG_TEST_FMT, size)
+
+def get_random_command_rsp(size):
+  return struct.pack(TRNG_TEST_RSP_FMT, 0x8001,
+                     struct.calcsize(TRNG_TEST_RSP_FMT) + size, 0, TRNG_TEST_CC)
+
+
+def trng_test(tpm):
+  """Download entropy samples from TRNG
+
+    Command structure, shared out of band with the test running on the target:
+
+    field     |    size  |                  note
+    ===================================================================
+    text_len  |    2     | size of the text to process, big endian
+
+  Args:
+    tpm: a tpm object used to communicate with the device
+
+  Raises:
+    subcmd.TpmTestError: on unexpected target responses
+  """
+  with open('/tmp/trng_output', 'wb') as f:
+    for x in range(0, TRNG_SAMPLE_COUNT):
+      wrapped_response = tpm.command(tpm.wrap_ext_command(TRNG_TEST_CC,
+                                     get_random_command(TRNG_SAMPLE_SIZE)))
+      if wrapped_response[:12] != get_random_command_rsp(TRNG_SAMPLE_SIZE):
+        raise subcmd.TpmTestError("Unexpected response to '%s': %s" %
+                                 ("trng", utils.hex_dump(wrapped_response)))
+      f.write(wrapped_response[12:])
+      print('%s %d%%\r' %( utils.cursor_back(), (x/10)), end=""),
+  print('%sSUCCESS: %s' % (utils.cursor_back(), 'trng'))