From 6024987733f20b2c43301beae9713c17935f0ce0 Mon Sep 17 00:00:00 2001
From: Alex Dale <sigquit@google.com>
Date: Wed, 15 Jun 2022 14:11:50 -0700
Subject: [PATCH] Return null system ID for built-in DRM cert devices.

[ Merge of http://go/wvgerrit/153489 ]

OEMCrypto does not provide an API for retrieving the system ID when
the TEE uses a built-in DRM certificate (provisioning 1.0).  New OEMs
and Android devices do not use prov 1.0; however, the Zimperium CDM
(at least the tests) use a built-in certificate and are failing
certain tests because of the missing system ID.  To address this
failure; the CDM SystemIdExtractor has been updated to return a null
system ID.

Bug: 235879962
Test: system_id_extractor_unittest
Change-Id: Ib4c2bd75a7825967b0aa9e31e144184ae18fe8fb
---
 libwvdrmengine/cdm/core/src/system_id_extractor.cpp   |  8 ++++++--
 .../cdm/core/test/system_id_extractor_unittest.cpp    | 11 ++++++++++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/libwvdrmengine/cdm/core/src/system_id_extractor.cpp b/libwvdrmengine/cdm/core/src/system_id_extractor.cpp
index 85d0859f..33da5757 100644
--- a/libwvdrmengine/cdm/core/src/system_id_extractor.cpp
+++ b/libwvdrmengine/cdm/core/src/system_id_extractor.cpp
@@ -60,8 +60,12 @@ bool SystemIdExtractor::ExtractSystemId(uint32_t* system_id) {
   bool success = false;
   switch (type) {
     case kClientTokenDrmCert:
-      LOGE("Cannot get a system ID from a DRM certificate");
-      return false;
+      LOGW(
+          "Cannot get a system ID from a DRM certificate, "
+          "using null system ID: security_level = %s",
+          RequestedSecurityLevelToString(security_level_));
+      *system_id = NULL_SYSTEM_ID;
+      return true;
     case kClientTokenKeybox:
       success = ExtractSystemIdProv20(system_id);
       break;
diff --git a/libwvdrmengine/cdm/core/test/system_id_extractor_unittest.cpp b/libwvdrmengine/cdm/core/test/system_id_extractor_unittest.cpp
index e08ff529..93635479 100644
--- a/libwvdrmengine/cdm/core/test/system_id_extractor_unittest.cpp
+++ b/libwvdrmengine/cdm/core/test/system_id_extractor_unittest.cpp
@@ -390,13 +390,22 @@ TEST_F(SystemIdExtractorTest, GetProvisioningMethod_Failed) {
 }
 
 TEST_F(SystemIdExtractorTest, GetProvisioningMethod_Unsupported) {
-  ExpectProvisioningType(kClientTokenDrmCert);
+  ExpectProvisioningType(static_cast<CdmClientTokenType>(9999));
   auto extractor = CreateExtractor(kLevelDefault);
   ASSERT_TRUE(extractor);
   uint32_t system_id;
   EXPECT_FALSE(extractor->ExtractSystemId(&system_id));
 }
 
+TEST_F(SystemIdExtractorTest, DrmCertDevice_NullSystemId) {
+  ExpectProvisioningType(kClientTokenDrmCert);
+  auto extractor = CreateExtractor(kLevelDefault);
+  ASSERT_TRUE(extractor);
+  uint32_t system_id;
+  EXPECT_TRUE(extractor->ExtractSystemId(&system_id));
+  EXPECT_EQ(system_id, NULL_SYSTEM_ID);
+}
+
 TEST_F(SystemIdExtractorTest, KeyboxDevice_Success) {
   ExpectProvisioningType(kClientTokenKeybox);
   EXPECT_CALL(*crypto_session_, GetTokenFromKeybox(kLevelDefault, NotNull()))