Exposing the Cast Signing Algorithm

[ Merge of http://go/wvgerrit/178076 ]

1. Exposing the Cast Signing Algorithm in cdm core.
2. Update core Cast tests to use new core CDM Cast signing API.

Bug: 279671867
Bug: 279672538
Test: com.google.android.wvts
Change-Id: Ia73c4b5e6dd61edf790bca97a321881d310e7a99
(cherry picked from commit 8996b624d73adf14db45e54653e7ddc513f3895c)

libwvdrmengine/cdm/core/src/cdm_engine.cpp

@@ -2340,4 +2340,48 @@ void CdmEngine::SetFastOtaKeyboxFallbackDurationRules() {
   }
   system_fallback_policy->SetFastBackoffDurationRules();
 }
+
+CdmResponseType CdmEngine::SignRSA(const std::string& wrapped_key,
+                                   const std::string& message,
+                                   std::string* signature,
+                                   RSA_Padding_Scheme padding_scheme) {
+  // Try to open cdm session.
+  CdmSessionId session_id;
+  auto sts = OpenSession("com.widevine", nullptr, nullptr, &session_id);
+  if (sts != NO_ERROR) {
+    LOGE("OpenSession failed, status: %d", static_cast<int>(sts));
+    return sts;
+  }
+
+  // Retrieve the cdm session
+  std::shared_ptr<CdmSession> session;
+  if (!session_map_.FindSession(session_id, &session)) {
+    LOGE("Session not found: session_id = %s", IdToString(session_id));
+    return CdmResponseType(SESSION_NOT_FOUND_24);
+  }
+
+  // Load cast private key for signing
+  CryptoWrappedKey key(CryptoWrappedKey::kRsa, wrapped_key);
+  sts = session->LoadCastPrivateKey(key);
+  if (sts != NO_ERROR) {
+    LOGE("LoadCastPrivateKey failed, status: %d", static_cast<int>(sts));
+    return sts;
+  }
+
+  // Generate Rsa signature for cast message
+  sts = session->GenerateRSASignature(message, signature, padding_scheme);
+  if (sts != NO_ERROR) {
+    LOGE("GenerateRSASignature failed, status: %d", static_cast<int>(sts));
+    return sts;
+  }
+
+  // Try to close cdm session.
+  sts = CloseSession(session_id);
+  if (sts != NO_ERROR) {
+    LOGE("CloseSession failed, status: %d", static_cast<int>(sts));
+    return sts;
+  }
+
+  return sts;
+}
 }  // namespace wvcdm

libwvdrmengine/cdm/core/src/cdm_session.cpp

@@ -1302,6 +1302,18 @@ bool CdmSession::HasRootOfTrustBeenRenewed() {
   return true;
 }
 
+CdmResponseType CdmSession::LoadCastPrivateKey(
+    const CryptoWrappedKey& private_key) {
+  return crypto_session_->LoadCertificatePrivateKey(private_key);
+}
+
+CdmResponseType CdmSession::GenerateRSASignature(const std::string& message,
+                                                 std::string* signature,
+                                                 RSA_Padding_Scheme scheme) {
+  return crypto_session_->GenerateRsaSignature(message, signature,
+                                               scheme);
+}
+
 // For testing only - takes ownership of pointers
 
 void CdmSession::set_license_parser(CdmLicense* license_parser) {

libwvdrmengine/cdm/core/src/crypto_session.cpp

@@ -1573,7 +1573,8 @@ CdmResponseType CryptoSession::GenerateDerivedKeys(
 }
 
 CdmResponseType CryptoSession::GenerateRsaSignature(const std::string& message,
-                                                    std::string* signature) {
+                                                    std::string* signature,
+                                                    RSA_Padding_Scheme scheme) {
   LOGV("Generating RSA signature: id = %u", oec_session_id_);
   RETURN_IF_NULL(signature, PARAMETER_NULL);
 
@@ -1590,7 +1591,7 @@ CdmResponseType CryptoSession::GenerateRsaSignature(const std::string& message,
               oec_session_id_, reinterpret_cast<const uint8_t*>(message.data()),
               message.size(),
               reinterpret_cast<uint8_t*>(const_cast<char*>(signature->data())),
-              &length, kSign_RSASSA_PSS),
+              &length, scheme),
           metrics_, oemcrypto_generate_rsa_signature_, sts,
           metrics::Pow2Bucket(length));
     });
@@ -3329,4 +3330,5 @@ CryptoSession* CryptoSessionFactory::MakeCryptoSession(
     metrics::CryptoMetrics* crypto_metrics) {
   return new CryptoSession(crypto_metrics);
 }
+
 }  // namespace wvcdm

libwvdrmengine/cdm/core/src/wv_cdm_types.cpp

@@ -867,6 +867,8 @@ const char* CdmResponseEnumToString(CdmResponseEnum cdm_response_enum) {
       return "STORE_ATSC_LICENSE_ERROR";
     case SESSION_NOT_FOUND_GENERIC_CRYPTO:
       return "SESSION_NOT_FOUND_GENERIC_CRYPTO";
+    case SESSION_NOT_FOUND_24:
+      return "SESSION_NOT_FOUND_24";
   }
   return UnknownValueRep(cdm_response_enum);
 }