Bug 1831983 - Add a constant time select function. r=mtHEADmaster

Differential Revision: https://phabricator.services.mozilla.com/D177803

3 files changed, 57 insertions, 0 deletions

diff --git a/gtests/util_gtest/manifest.mn b/gtests/util_gtest/manifest.mn
index 87ebdfb33..279e276ec 100644
--- a/gtests/util_gtest/manifest.mn
+++ b/gtests/util_gtest/manifest.mn
@@ -13,6 +13,7 @@ CPPSRCS = \
         util_memcmpzero_unittest.cc \
         util_pkcs11uri_unittest.cc \
         util_secasn1d_unittest.cc \
+        util_select_unittest.cc \
         util_utf8_unittest.cc \
         $(NULL)
 
diff --git a/gtests/util_gtest/util_gtest.gyp b/gtests/util_gtest/util_gtest.gyp
index e924df04f..df1a095dc 100644
--- a/gtests/util_gtest/util_gtest.gyp
+++ b/gtests/util_gtest/util_gtest.gyp
@@ -17,6 +17,7 @@
         'util_memcmpzero_unittest.cc',
         'util_pkcs11uri_unittest.cc',
         'util_secasn1d_unittest.cc',
+        'util_select_unittest.cc',
         'util_utf8_unittest.cc',
       ],
       'dependencies': [
diff --git a/gtests/util_gtest/util_select_unittest.cc b/gtests/util_gtest/util_select_unittest.cc
new file mode 100644
index 000000000..f62357c9b
--- /dev/null
+++ b/gtests/util_gtest/util_select_unittest.cc
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "scoped_ptrs_util.h"
+
+namespace nss_test {
+
+class SelectTest : public ::testing::Test {
+ protected:
+  void test_select(std::vector<uint8_t> &dest, const std::vector<uint8_t> &src0,
+                   const std::vector<uint8_t> &src1, unsigned char b) {
+    EXPECT_EQ(src0.size(), src1.size());
+    EXPECT_GE(dest.size(), src0.size());
+    return NSS_SecureSelect(dest.data(), src0.data(), src1.data(), src0.size(),
+                            b);
+  };
+};
+
+TEST_F(SelectTest, TestSelectZero) {
+  std::vector<uint8_t> dest(32, 255);
+  std::vector<uint8_t> src0(32, 0);
+  std::vector<uint8_t> src1(32, 1);
+  test_select(dest, src0, src1, 0);
+  EXPECT_EQ(dest, src0);
+}
+
+TEST_F(SelectTest, TestSelectOne) {
+  std::vector<uint8_t> dest(32, 255);
+  std::vector<uint8_t> src0(32, 0);
+  std::vector<uint8_t> src1(32, 1);
+  test_select(dest, src0, src1, 1);
+  EXPECT_EQ(dest, src1);
+}
+
+TEST_F(SelectTest, TestSelect170) {
+  std::vector<uint8_t> dest(32, 255);
+  std::vector<uint8_t> src0(32, 0);
+  std::vector<uint8_t> src1(32, 1);
+  test_select(dest, src0, src1, 170);
+  EXPECT_EQ(dest, src1);
+}
+
+TEST_F(SelectTest, TestSelect255) {
+  std::vector<uint8_t> dest(32, 255);
+  std::vector<uint8_t> src0(32, 0);
+  std::vector<uint8_t> src1(32, 1);
+  test_select(dest, src0, src1, 255);
+  EXPECT_EQ(dest, src1);
+}
+
+}  // namespace nss_test