Refactor key sessions to move them out of crypto session.

Merge from Widevine repo of http://go/wvgerrit/41833

Bug: 64003606
Test: in child CL

Change-Id: I3e1d36d0b0944dce0fb1515257bc15243d76f397

libwvdrmengine/cdm/core/include/content_key_session.h

@@ -0,0 +1,51 @@
+#ifndef WVCDM_CORE_CONTENT_KEY_SESSSION_H_
+#define WVCDM_CORE_CONTENT_KEY_SESSSION_H_
+
+#include "key_session.h"
+#include "timer_metric.h"
+
+namespace wvcdm {
+
+class DefaultKeySession : public KeySession {
+ public:
+  DefaultKeySession(CryptoSessionId oec_session_id,
+                    metrics::CryptoMetrics* metrics)
+      : KeySession(metrics), oec_session_id_(oec_session_id) {}
+  virtual ~DefaultKeySession() {}
+
+  KeySessionType Type() { return kDefault; }
+
+  // Generate Derived Keys for DefaultKeySession
+  bool GenerateDerivedKeys(const std::string& message);
+
+  // Generate Derived Keys (from session key) for DefaultKeySession
+  bool GenerateDerivedKeys(const std::string& message,
+                           const std::string& session_key);
+
+  // Load Keys for DefaultKeySession
+  OEMCryptoResult LoadKeys(const std::string& message,
+                           const std::string& signature,
+                           const std::string& mac_key_iv,
+                           const std::string& mac_key,
+                           const std::vector<CryptoKey>& keys,
+                           const std::string& provider_session_token,
+                           CdmCipherMode* cipher_mode,
+                           const std::string& srm_requirement);
+
+  // Select Key for DefaultKeySession
+  OEMCryptoResult SelectKey(const std::string& key_id,
+                            CdmCipherMode cipher_mode);
+
+  // Decrypt for DefaultKeySession
+  OEMCryptoResult Decrypt(const CdmDecryptionParameters& params,
+                          OEMCrypto_DestBufferDesc& buffer_descriptor,
+                          OEMCrypto_CENCEncryptPatternDesc& pattern_descriptor);
+
+ private:
+  CryptoSessionId oec_session_id_;
+  KeyId cached_key_id_;
+};
+
+}  // namespace wvcdm
+
+#endif  // WVCDM_CORE_CONTENT_KEY_SESSSION_H_

libwvdrmengine/cdm/core/include/crypto_session.h

@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "OEMCryptoCENC.h"
+#include "key_session.h"
 #include "lock.h"
 #include "metrics_collections.h"
 #include "oemcrypto_adapter.h"
@@ -22,37 +23,13 @@ class CryptoKey;
 class UsageTableHeader;
 
 typedef std::map<std::string, CryptoKey*> CryptoKeyMap;
-typedef std::map<std::string, CryptoSessionId> SubLicenseSessionMap;
 
-class KeySession {
- protected:
-  KeySession(metrics::CryptoMetrics* metrics) : metrics_(metrics) {}
-
- public:
-  typedef enum { kDefault, kSubLicense } KeySessionType;
-  virtual ~KeySession() {}
-  virtual KeySessionType Type() = 0;
-  virtual bool GenerateDerivedKeys(const std::string& message) = 0;
-  virtual bool GenerateDerivedKeys(const std::string& message,
-                                   const std::string& session_key) = 0;
-  virtual OEMCryptoResult LoadKeys(const std::string& message,
-                                   const std::string& signature,
-                                   const std::string& mac_key_iv,
-                                   const std::string& mac_key,
-                                   const std::vector<CryptoKey>& keys,
-                                   const std::string& provider_session_token,
-                                   CdmCipherMode* cipher_mode,
-                                   const std::string& srm_requirement) = 0;
-  virtual OEMCryptoResult SelectKey(const std::string& key_id,
-                                    CdmCipherMode cipher_mode) = 0;
-  virtual OEMCryptoResult Decrypt(
-      const CdmDecryptionParameters& params,
-      OEMCrypto_DestBufferDesc& buffer_descriptor,
-      OEMCrypto_CENCEncryptPatternDesc& pattern_descriptor) = 0;
-
- protected:
-  metrics::CryptoMetrics* metrics_;
-};
+// Crypto session utility functions used by KeySession implementations.
+void GenerateMacContext(const std::string& input_context,
+                        std::string* deriv_context);
+void GenerateEncryptContext(const std::string& input_context,
+                            std::string* deriv_context);
+size_t GetOffset(std::string message, std::string field);
 
 class CryptoSession {
  public:

libwvdrmengine/cdm/core/include/key_session.h

@@ -0,0 +1,44 @@
+#ifndef WVCDM_CORE_KEY_SESSSION_H_
+#define WVCDM_CORE_KEY_SESSSION_H_
+
+#include "metrics_collections.h"
+
+namespace wvcdm {
+
+class CryptoKey;
+
+class KeySession {
+ protected:
+  KeySession(metrics::CryptoMetrics* metrics) : metrics_(metrics) {}
+
+ public:
+  typedef enum { kDefault, kSubLicense } KeySessionType;
+  virtual ~KeySession() {}
+  virtual KeySessionType Type() = 0;
+  virtual bool GenerateDerivedKeys(const std::string& message) = 0;
+  virtual bool GenerateDerivedKeys(const std::string& message,
+                                   const std::string& session_key) = 0;
+  virtual OEMCryptoResult LoadKeys(const std::string& message,
+                                   const std::string& signature,
+                                   const std::string& mac_key_iv,
+                                   const std::string& mac_key,
+                                   const std::vector<CryptoKey>& keys,
+                                   const std::string& provider_session_token,
+                                   CdmCipherMode* cipher_mode,
+                                   const std::string& srm_requirement) = 0;
+  virtual OEMCryptoResult SelectKey(const std::string& key_id,
+                                    CdmCipherMode cipher_mode) = 0;
+  virtual OEMCryptoResult Decrypt(
+      const CdmDecryptionParameters& params,
+      OEMCrypto_DestBufferDesc& buffer_descriptor,
+      OEMCrypto_CENCEncryptPatternDesc& pattern_descriptor) = 0;
+
+ protected:
+  metrics::CryptoMetrics* metrics_;
+};
+
+typedef std::map<std::string, CryptoSessionId> SubLicenseSessionMap;
+
+}  // namespace wvcdm
+
+#endif  // WVCDM_CORE_KEY_SESSSION_H_

libwvdrmengine/cdm/core/include/sublicense_key_session.h

@@ -0,0 +1,91 @@
+#ifndef WVCDM_CORE_SUBLICENSE_KEY_SESSSION_H_
+#define WVCDM_CORE_SUBLICENSE_KEY_SESSSION_H_
+
+#include "crypto_key.h"
+#include "key_session.h"
+
+namespace wvcdm {
+
+class SubLicenseKeySession : public KeySession {
+  typedef enum {
+    kInitializing,
+    kInitialLicenseLoaded,
+    kInitialLicenseFailed,
+  } SubLicenseState;
+
+ public:
+  SubLicenseKeySession(SubLicenseSessionMap& sub_license_oec_sessions,
+                       metrics::CryptoMetrics* metrics,
+                       const std::string& wrapped_private_device_key,
+                       SecurityLevel requested_security_level,
+                       const std::string& group_master_key_id);
+
+  virtual ~SubLicenseKeySession();
+
+  KeySessionType Type() { return kSubLicense; }
+
+  // This version of GenerateDerivedKeys is for devices using keyboxes. It is
+  // not supported using sub licenses.
+  bool GenerateDerivedKeys(const std::string&) { return false; }
+
+  // GenerateDerivedKeys is called for each open oemcrypto session and is only
+  // called once.
+  bool GenerateDerivedKeys(const std::string& message,
+                           const std::string& session_key);
+
+  // Load the keys in |keys|. The initial keys are saved for key rotation.
+  OEMCryptoResult LoadKeys(const std::string& message,
+                           const std::string& signature,
+                           const std::string& mac_key_iv,
+                           const std::string& mac_key,
+                           const std::vector<CryptoKey>& keys,
+                           const std::string& provider_session_token,
+                           CdmCipherMode* cipher_mode,
+                           const std::string& srm_requirement);
+
+  // Each oemcrypto session contains a single key. Find the right sub session
+  // and save it's id as the selected oemcrypto session.
+  OEMCryptoResult SelectKey(const std::string& key_id,
+                            CdmCipherMode cipher_mode);
+
+  // Decrypt performs the decryption using the selected oemcrypto session.
+  // TODO(jfore): Support DecryptInChunks.
+  OEMCryptoResult Decrypt(const CdmDecryptionParameters& params,
+                          OEMCrypto_DestBufferDesc& buffer_descriptor,
+                          OEMCrypto_CENCEncryptPatternDesc& pattern_descriptor);
+
+ private:
+  // Destroy each open oemcrypto session and relace them with new ones.
+  OEMCryptoResult ResetCryptoSessions();
+
+  // DoLoadKeys loads a single key into each oemcrypto session.
+  OEMCryptoResult DoLoadKeys(const std::string& message,
+                             const std::string& signature,
+                             const std::string& mac_key_iv,
+                             const std::string& mac_key,
+                             const std::vector<CryptoKey>& keys,
+                             const std::string& provider_session_token,
+                             CdmCipherMode* cipher_mode,
+                             const std::string& srm_requirement);
+
+  // DoLoadKeys loads a single key into each oemcrypto session.
+  OEMCryptoResult DoSubLicenseLoadKeys(
+      const std::string& message, const std::string& signature,
+      const std::string& mac_key_iv, const std::string& mac_key,
+      const CryptoKey& key, const std::string& provider_session_token,
+      CdmCipherMode*, const std::string& srm_requirement);
+
+  SubLicenseState state_;
+  std::string cached_sub_session_key_id_;
+  std::string wrapped_private_device_key_;
+  std::string message_;
+  std::string session_key_;
+  std::vector<CryptoKey> keys_;
+  SubLicenseSessionMap& sub_license_oec_sessions_;
+  SecurityLevel requested_security_level_;
+  KeyId group_master_key_id_;
+};
+
+}  // namespace wvcdm
+
+#endif  // WVCDM_CORE_SUBLICENSE_KEY_SESSSION_H_