Unit test for pointer alignment

Merge from Widevine repo of http://go/wvgerrit/66708

This adds a unit test to verify that LoadKeys still works if the message is not
word alligned.

Test: unit tests on desktop and taimen (x86 and arm)
Bug: 68783727
Change-Id: Ib081a2c21af710b294772513c2c777ef1ac0daf0

libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp

@@ -1244,6 +1244,33 @@ TEST_F(OEMCryptoSessionTests, LoadKeyWithBadVerification) {
   ASSERT_NE(OEMCrypto_SUCCESS, sts);
 }
 
+// This test verifies that LoadKeys still works when the message is not aligned
+// in memory on a word (2 or 4 byte) boundary.
+TEST_F(OEMCryptoSessionTests, LoadKeyUnalignedMessage) {
+  Session s;
+  ASSERT_NO_FATAL_FAILURE(s.open());
+  ASSERT_NO_FATAL_FAILURE(InstallTestSessionKeys(&s));
+  ASSERT_NO_FATAL_FAILURE(s.FillSimpleMessage(
+      kDuration, wvoec::kControlNonceEnabled, s.get_nonce()));
+  ASSERT_NO_FATAL_FAILURE(s.EncryptAndSign());
+  std::vector<uint8_t> buffer(1, '0');  // A string of 1 byte long.
+  size_t offset = buffer.size();
+  ASSERT_EQ(1u, offset);
+  // We assume that vectors are allocated on as a small chunk of data that is
+  // aligned on a word boundary.  I.e. we assume buffer is word aligned. Next,
+  // we append the message to buffer after the single padding byte.
+  buffer.insert(buffer.end(), s.message_ptr(),
+                s.message_ptr() + s.message_size());
+  // Thus, buffer[offset] is NOT word aligned.
+  const uint8_t* unaligned_message = &buffer[offset];
+  OEMCryptoResult sts = OEMCrypto_LoadKeys(
+      s.session_id(), unaligned_message, s.message_size(), &s.signature()[0],
+      s.signature().size(), s.enc_mac_keys_iv_substr(), s.enc_mac_keys_substr(),
+      s.num_keys(), s.key_array(), GetSubstring(), GetSubstring(),
+      OEMCrypto_ContentLicense);
+  ASSERT_EQ(OEMCrypto_SUCCESS, sts);
+}
+
 // This tests each key control block verification string in the range kc09-kc1?.
 class SessionTestAlternateVerification : public OEMCryptoSessionTests,
                                          public WithParamInterface<int> {