Detect when unable to meet policy requirements

[ Merge of http://go/wvgerrit/25781 ]

The security level (software/hardware, decryption/decode)
in the policy that specified how the key was to be used was
not being respected for L3. Playback would either continue or
a vendor specific error would be thrown.

If the device cannot use the key as permitted by the policy
CryptoException#ERROR_INSUFFICIENT_OUTPUT_PROTECTION will be thrown.

Test: Verified by WV unit+integration tests.
      Verified by WidevineDashPolicyTests
      Verified by WidevineDashPolicyTests#testL3SoftwareSecureDecoderRequired,
      testL3HardwareSecureCryptoRequired, testL3HardwareSecureDecodeRequired,
      testL3SecureVideoPathRequired.

b/31913737
b/31913439

Change-Id: Ibfc7f3dd6fc7264e8cf9b0d33f6f8d619eed6c00

libwvdrmengine/cdm/core/include/policy_engine.h

@@ -34,6 +34,10 @@ class PolicyEngine {
   // status is not calculated to avoid overhead in the decryption path.
   virtual bool CanDecryptContent(const KeyId& key_id);
 
+  // Verifies whether the policy allows use of the specified key of
+  // a given security level for content decryption.
+  virtual bool CanUseKey(const KeyId& key_id, CdmSecurityLevel security_level);
+
   // OnTimerEvent is called when a timer fires. It notifies the Policy Engine
   // that the timer has fired and dispatches the relevant events through
   // |event_listener_|.

libwvdrmengine/cdm/core/include/wv_cdm_types.h

@@ -295,6 +295,7 @@ enum CdmResponseType {
   RELEASE_USAGE_INFO_FAILED,
   INCORRECT_USAGE_SUPPORT_TYPE_1,
   INCORRECT_USAGE_SUPPORT_TYPE_2, /* 255 */
+  KEY_PROHIBITED_FOR_SECURITY_LEVEL,
 };
 
 enum CdmKeyStatus {
@@ -392,6 +393,16 @@ struct CdmUsageEntryInfo {
   std::string usage_info_file_name;
 };
 
+enum CdmKeySecurityLevel {
+  kKeySecurityLevelUnset,
+  kSoftwareSecureCrypto,
+  kSoftwareSecureDecode,
+  kHardwareSecureCrypto,
+  kHardwareSecureDecode,
+  kHardwareSecureAll,
+  kKeySecurityLevelUnknown,
+};
+
 class CdmKeyAllowedUsage {
  public:
   CdmKeyAllowedUsage() {
@@ -408,6 +419,7 @@ class CdmKeyAllowedUsage {
     generic_decrypt = false;
     generic_sign = false;
     generic_verify = false;
+    key_security_level_ = kKeySecurityLevelUnset;
     valid_ = false;
   }
 
@@ -418,7 +430,8 @@ class CdmKeyAllowedUsage {
         generic_encrypt != other.generic_encrypt ||
         generic_decrypt != other.generic_decrypt ||
         generic_sign != other.generic_sign ||
-        generic_verify != other.generic_verify) {
+        generic_verify != other.generic_verify ||
+        key_security_level_ != other.key_security_level_) {
       return false;
     }
     return true;
@@ -430,6 +443,7 @@ class CdmKeyAllowedUsage {
   bool generic_decrypt;
   bool generic_sign;
   bool generic_verify;
+  CdmKeySecurityLevel key_security_level_;
 
  private:
   bool valid_;

libwvdrmengine/cdm/core/src/cdm_session.cpp

@@ -553,6 +553,9 @@ CdmResponseType CdmSession::Decrypt(const CdmDecryptionParameters& params) {
     return policy_engine_->IsLicenseForFuture() ? DECRYPT_NOT_READY : NEED_KEY;
   }
 
+  if (!policy_engine_->CanUseKey(*params.key_id, security_level_))
+    return KEY_PROHIBITED_FOR_SECURITY_LEVEL;
+
   CdmResponseType status = crypto_session_->Decrypt(params);
 
   if (status == NO_ERROR) {

libwvdrmengine/cdm/core/src/license_key_status.cpp

@@ -169,6 +169,31 @@ void LicenseKeyStatus::ParseContentKey(const KeyContainer& key) {
     allowed_usage_.decrypt_to_clear_buffer = true;
     allowed_usage_.decrypt_to_secure_buffer = true;
   }
+
+  if (key.has_level()) {
+    switch (key.level()) {
+      case KeyContainer::SW_SECURE_CRYPTO:
+        allowed_usage_.key_security_level_ = kSoftwareSecureCrypto;
+        break;
+      case KeyContainer::SW_SECURE_DECODE:
+        allowed_usage_.key_security_level_ = kSoftwareSecureDecode;
+        break;
+      case KeyContainer::HW_SECURE_CRYPTO:
+        allowed_usage_.key_security_level_ = kHardwareSecureCrypto;
+        break;
+      case KeyContainer::HW_SECURE_DECODE:
+        allowed_usage_.key_security_level_ = kHardwareSecureDecode;
+        break;
+      case KeyContainer::HW_SECURE_ALL:
+        allowed_usage_.key_security_level_ = kHardwareSecureAll;
+        break;
+      default:
+        allowed_usage_.key_security_level_ = kKeySecurityLevelUnknown;
+        break;
+    }
+  } else {
+    allowed_usage_.key_security_level_ = kKeySecurityLevelUnset;
+  }
   allowed_usage_.SetValid();
 
   if (key.video_resolution_constraints_size() > 0) {

libwvdrmengine/cdm/core/src/policy_engine.cpp

@@ -283,6 +283,32 @@ CdmResponseType PolicyEngine::QueryKeyAllowedUsage(
   return KEY_NOT_FOUND_1;
 }
 
+bool PolicyEngine::CanUseKey(
+    const KeyId& key_id,
+    CdmSecurityLevel security_level) {
+
+  if (security_level == kSecurityLevelL1) return true;
+
+  CdmKeyAllowedUsage key_usage;
+  CdmResponseType status = QueryKeyAllowedUsage(key_id, &key_usage);
+
+  if (status != NO_ERROR) return false;
+
+  // L1 has already been addressed so verify that L2/3 are allowed
+  switch (key_usage.key_security_level_) {
+    case kKeySecurityLevelUnset:
+      return true;
+    case kSoftwareSecureCrypto:
+      return security_level == kSecurityLevelL2 ||
+          security_level == kSecurityLevelL3;
+    case kSoftwareSecureDecode:
+    case kHardwareSecureCrypto:
+      return security_level == kSecurityLevelL2;
+    default:
+      return false;
+  }
+}
+
 bool PolicyEngine::GetSecondsSinceStarted(int64_t* seconds_since_started) {
   if (playback_start_time_ == 0) return false;
 

libwvdrmengine/cdm/core/test/license_keys_unittest.cpp

@@ -157,9 +157,11 @@ class LicenseKeysTest : public ::testing::Test {
   }
 
   virtual void ExpectAllowedUsageContent(
-      const CdmKeyAllowedUsage& key_usage, KeyFlag secure, KeyFlag clear) {
+      const CdmKeyAllowedUsage& key_usage, KeyFlag secure, KeyFlag clear,
+      CdmKeySecurityLevel key_security_level) {
     EXPECT_EQ(key_usage.decrypt_to_secure_buffer, secure == kKeyFlagTrue);
     EXPECT_EQ(key_usage.decrypt_to_clear_buffer, clear == kKeyFlagTrue);
+    EXPECT_EQ(key_usage.key_security_level_, key_security_level);
     EXPECT_FALSE(key_usage.generic_encrypt);
     EXPECT_FALSE(key_usage.generic_decrypt);
     EXPECT_FALSE(key_usage.generic_sign);
@@ -420,36 +422,41 @@ TEST_F(LicenseKeysTest, AllowedUsageNull) {
 
   CdmKeyAllowedUsage usage_2;
   EXPECT_TRUE(license_keys_.GetAllowedUsage(c_key, &usage_2));
-  ExpectAllowedUsageContent(usage_2, kContentClearTrue, kContentSecureTrue);
+  ExpectAllowedUsageContent(usage_2, kContentClearTrue, kContentSecureTrue,
+                            kKeySecurityLevelUnset);
 
   CdmKeyAllowedUsage usage_3;
   EXPECT_TRUE(license_keys_.GetAllowedUsage(os_key, &usage_3));
-  ExpectAllowedUsageContent(usage_3, kContentClearFalse, kContentSecureFalse);
+  ExpectAllowedUsageContent(usage_3, kContentClearFalse, kContentSecureFalse,
+                            kKeySecurityLevelUnset);
 }
 
 TEST_F(LicenseKeysTest, AllowedUsageContent) {
   StageContentKeys();
   CdmKeyAllowedUsage u_sw_crypto;
   EXPECT_TRUE(license_keys_.GetAllowedUsage(ck_sw_crypto, &u_sw_crypto));
-  ExpectAllowedUsageContent(u_sw_crypto, kContentSecureTrue, kContentClearTrue);
+  ExpectAllowedUsageContent(u_sw_crypto, kContentSecureTrue, kContentClearTrue,
+                            kSoftwareSecureCrypto);
 
   CdmKeyAllowedUsage u_sw_decode;
   EXPECT_TRUE(license_keys_.GetAllowedUsage(ck_sw_decode, &u_sw_decode));
-  ExpectAllowedUsageContent(u_sw_decode, kContentSecureTrue, kContentClearTrue);
+  ExpectAllowedUsageContent(u_sw_decode, kContentSecureTrue, kContentClearTrue,
+                            kSoftwareSecureDecode);
 
   CdmKeyAllowedUsage u_hw_crypto;
   EXPECT_TRUE(license_keys_.GetAllowedUsage(ck_hw_crypto, &u_hw_crypto));
-  ExpectAllowedUsageContent(u_hw_crypto, kContentSecureTrue, kContentClearTrue);
+  ExpectAllowedUsageContent(u_hw_crypto, kContentSecureTrue, kContentClearTrue,
+                            kHardwareSecureCrypto);
 
   CdmKeyAllowedUsage u_hw_decode;
   EXPECT_TRUE(license_keys_.GetAllowedUsage(ck_hw_decode, &u_hw_decode));
   ExpectAllowedUsageContent(u_hw_decode, kContentSecureTrue,
-                            kContentClearFalse);
+                            kContentClearFalse, kHardwareSecureDecode);
 
   CdmKeyAllowedUsage u_hw_secure;
   EXPECT_TRUE(license_keys_.GetAllowedUsage(ck_hw_secure, &u_hw_secure));
   ExpectAllowedUsageContent(u_hw_secure, kContentSecureTrue,
-                            kContentClearFalse);
+                            kContentClearFalse, kHardwareSecureAll);
 }
 
 TEST_F(LicenseKeysTest, AllowedUsageOperatorSession) {

libwvdrmengine/cdm/core/test/policy_engine_unittest.cpp

@@ -1259,6 +1259,63 @@ TEST_F(PolicyEngineTest, PlaybackOk_CanStoreGracePeriod) {
   EXPECT_EQ(kPlaybackStartTime, policy_engine_->GetGracePeriodEndTime());
 }
 
+struct KeySecurityLevelParams {
+  bool is_security_level_set;
+  License::KeyContainer::SecurityLevel security_level;
+  bool expect_can_L1_use_key;
+  bool expect_can_L2_use_key;
+  bool expect_can_L3_use_key;
+  bool expect_can_L_unknown_use_key;
+};
+
+KeySecurityLevelParams key_security_test_vectors[] = {
+  { false, License::KeyContainer::HW_SECURE_ALL, true, true, true, true },
+  { true, License::KeyContainer::SW_SECURE_CRYPTO, true, true, true, false },
+  { true, License::KeyContainer::SW_SECURE_DECODE, true, true, false, false },
+  { true, License::KeyContainer::HW_SECURE_CRYPTO, true, true, false, false },
+  { true, License::KeyContainer::HW_SECURE_DECODE, true, false, false, false },
+  { true, License::KeyContainer::HW_SECURE_ALL, true, false, false, false },
+};
+
+class PolicyEngineKeySecurityLevelTest
+  : public PolicyEngineTest,
+    public ::testing::WithParamInterface<KeySecurityLevelParams*> {};
+
+TEST_P(PolicyEngineKeySecurityLevelTest, CanUseKey) {
+
+  KeySecurityLevelParams* param = GetParam();
+
+  license_.clear_key();
+
+  License::KeyContainer* content_key = license_.add_key();
+  content_key->set_type(License::KeyContainer::CONTENT);
+  content_key->set_id(kKeyId);
+  if (param->is_security_level_set)
+    content_key->set_level(param->security_level);
+
+  EXPECT_CALL(*mock_clock_, GetCurrentTime())
+      .WillOnce(Return(kLicenseStartTime + 1));
+
+  ExpectSessionKeysChange(kKeyStatusUsable, true);
+  EXPECT_CALL(mock_event_listener_, OnExpirationUpdate(_, _));
+
+  policy_engine_->SetLicense(license_);
+
+  EXPECT_EQ(param->expect_can_L1_use_key,
+            policy_engine_->CanUseKey(kKeyId, kSecurityLevelL1));
+  EXPECT_EQ(param->expect_can_L2_use_key,
+            policy_engine_->CanUseKey(kKeyId, kSecurityLevelL2));
+  EXPECT_EQ(param->expect_can_L3_use_key,
+            policy_engine_->CanUseKey(kKeyId, kSecurityLevelL3));
+  EXPECT_EQ(param->expect_can_L_unknown_use_key,
+            policy_engine_->CanUseKey(kKeyId, kSecurityLevelUnknown));
+}
+
+INSTANTIATE_TEST_CASE_P(
+    PolicyEngine, PolicyEngineKeySecurityLevelTest,
+    ::testing::Range(&key_security_test_vectors[0],
+                     &key_security_test_vectors[5]));
+
 class PolicyEngineKeyAllowedUsageTest : public PolicyEngineTest {
  protected:
   enum KeyFlag {
@@ -1287,9 +1344,11 @@ class PolicyEngineKeyAllowedUsageTest : public PolicyEngineTest {
 
 
   void ExpectAllowedContentKeySettings(const CdmKeyAllowedUsage& key_usage,
-                                       KeyFlag secure, KeyFlag clear) {
+                                       KeyFlag secure, KeyFlag clear,
+                                       CdmKeySecurityLevel key_security_level) {
     EXPECT_EQ(key_usage.decrypt_to_secure_buffer, secure == kKeyFlagTrue);
     EXPECT_EQ(key_usage.decrypt_to_clear_buffer, clear == kKeyFlagTrue);
+    EXPECT_EQ(key_usage.key_security_level_, key_security_level);
     EXPECT_FALSE(key_usage.generic_encrypt);
     EXPECT_FALSE(key_usage.generic_decrypt);
     EXPECT_FALSE(key_usage.generic_sign);
@@ -1307,22 +1366,24 @@ class PolicyEngineKeyAllowedUsageTest : public PolicyEngineTest {
     EXPECT_EQ(key_usage.generic_verify, verify == kKeyFlagTrue);
   }
 
-  void ExpectSecureContentKey(const KeyId& key_id) {
+  void ExpectSecureContentKey(const KeyId& key_id,
+                              CdmKeySecurityLevel key_security_level) {
     CdmKeyAllowedUsage key_usage;
     EXPECT_EQ(NO_ERROR,
               policy_engine_->QueryKeyAllowedUsage(key_id, &key_usage));
 
     ExpectAllowedContentKeySettings(key_usage, kContentSecureTrue,
-                                    kContentSecureFalse);
+                                    kContentSecureFalse, key_security_level);
   }
 
-  void ExpectLessSecureContentKey(const KeyId& key_id) {
+  void ExpectLessSecureContentKey(const KeyId& key_id,
+                                  CdmKeySecurityLevel key_security_level) {
     CdmKeyAllowedUsage key_usage;
     EXPECT_EQ(NO_ERROR,
               policy_engine_->QueryKeyAllowedUsage(key_id, &key_usage));
 
     ExpectAllowedContentKeySettings(key_usage, kContentSecureTrue,
-                                    kContentSecureTrue);
+                                    kContentSecureTrue, key_security_level);
   }
 
   void ExpectOperatorSessionKey(const KeyId& key_id, KeyFlag encrypt,
@@ -1388,8 +1449,8 @@ TEST_F(PolicyEngineKeyAllowedUsageTest, AllowedUsageBasic) {
 
   policy_engine_->SetLicense(license_);
 
-  ExpectSecureContentKey(kKeyId);
+  ExpectSecureContentKey(kKeyId, kHardwareSecureAll);
-  ExpectLessSecureContentKey(kAnotherKeyId);
+  ExpectLessSecureContentKey(kAnotherKeyId, kKeySecurityLevelUnset);
   ExpectOperatorSessionKey(kGenericKeyId, kEncryptNull, kDecryptNull,
                            kSignTrue, kVerifyNull);
 
@@ -1443,8 +1504,8 @@ TEST_F(PolicyEngineKeyAllowedUsageTest, AllowedUsageGeneric) {
 
   policy_engine_->SetLicense(license_);
 
-  ExpectSecureContentKey(kKeyId);
+  ExpectSecureContentKey(kKeyId, kHardwareSecureDecode);
-  ExpectLessSecureContentKey(kAnotherKeyId);
+  ExpectLessSecureContentKey(kAnotherKeyId, kHardwareSecureCrypto);
   ExpectOperatorSessionKey(kGenericEncryptKeyId, kEncryptTrue, kDecryptFalse,
                            kSignFalse, kVerifyFalse);
   ExpectOperatorSessionKey(kGenericDecryptKeyId, kEncryptFalse, kDecryptTrue,

libwvdrmengine/cdm/core/test/test_printers.cpp

@@ -568,6 +568,9 @@ void PrintTo(const enum CdmResponseType& value, ::std::ostream* os) {
     case INCORRECT_USAGE_SUPPORT_TYPE_2:
       *os << "INCORRECT_USAGE_SUPPORT_TYPE_2";
       break;
+    case KEY_PROHIBITED_FOR_SECURITY_LEVEL:
+      *os << "KEY_PROHIBITED_FOR_SECURITY_LEVEL";
+      break;
 
     default:
       *os                                        << "Unknown CdmResponseType";

libwvdrmengine/include/mapErrors-inl.h

@@ -377,6 +377,7 @@ static android::status_t mapCdmResponseType(wvcdm::CdmResponseType res) {
       return android::ERROR_DRM_CANNOT_HANDLE;
     case wvcdm::INSUFFICIENT_OUTPUT_PROTECTION:
     case wvcdm::ANALOG_OUTPUT_ERROR:
+    case wvcdm::KEY_PROHIBITED_FOR_SECURITY_LEVEL:
       return android::ERROR_DRM_INSUFFICIENT_OUTPUT_PROTECTION;
     case wvcdm::SESSION_NOT_FOUND_12:
       return kSessionNotFound12;

libwvdrmengine/mediacrypto/src/WVCryptoPlugin.cpp

@@ -322,9 +322,14 @@ status_t WVCryptoPlugin::attemptDecrypt(const CdmDecryptionParameters& params,
             "Error decrypting data: unspecified error");
         break;
       case wvcdm::INSUFFICIENT_OUTPUT_PROTECTION:
+      case wvcdm::ANALOG_OUTPUT_ERROR:
         errorDetailMsg->setTo(
             "Error decrypting data: insufficient output protection");
         break;
+      case wvcdm::KEY_PROHIBITED_FOR_SECURITY_LEVEL:
+        errorDetailMsg->setTo(
+            "Error decrypting data: key prohibited for security level");
+        break;
       default:
         actionableError = false;
         break;

libwvdrmengine/mediacrypto/src_hidl/WVCryptoPlugin.cpp

@@ -354,9 +354,14 @@ status_t WVCryptoPlugin::attemptDecrypt(const CdmDecryptionParameters& params,
             "Error decrypting data: unspecified error");
         break;
       case wvcdm::INSUFFICIENT_OUTPUT_PROTECTION:
+      case wvcdm::ANALOG_OUTPUT_ERROR:
         errorDetailMsg->assign(
             "Error decrypting data: insufficient output protection");
         break;
+      case wvcdm::KEY_PROHIBITED_FOR_SECURITY_LEVEL:
+        errorDetailMsg->assign(
+            "Error decrypting data: key prohibited for security level");
+        break;
       default:
         actionableError = false;
         break;