OEMCrypto Usage Tables

This CL adds usage tables to the OEMCrypto reference implementation
(mock) and unit tests.

There is also a new parameter called oem_crypto_require_usage_tables
that determines if the usage tables are required or not.  This is set
to true for Android and false for all other platforms.

This CL is most of OEMCrypto version 9 updates.

This CL is a copy of
https://widevine-internal-review.googlesource.com/#/c/9720
https://widevine-internal-review.googlesource.com/#/c/9874
https://widevine-internal-review.googlesource.com/#/c/9873

Change-Id: I78c4f7651306f9f79ba2260c3e04fb1eca7e20e3

libwvdrmengine/oemcrypto/mock/src/oemcrypto_usage_table_mock.h

@@ -0,0 +1,106 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+//  Mock implementation of OEMCrypto APIs
+//
+#ifndef WVOEC_MOCK_OEMCRYPTO_USAGE_TABLE_MOCK_H_
+#define WVOEC_MOCK_OEMCRYPTO_USAGE_TABLE_MOCK_H_
+
+#include <stdint.h>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "clock.h"
+#include "lock.h"
+#include "OEMCryptoCENC.h"
+#include "openssl/sha.h"
+#include "wv_cdm_constants.h"
+
+namespace wvoec_mock {
+
+class SessionContext;
+class CryptoEngine;
+
+struct StoredUsageEntry {
+  // To save disk space, we only store a hash of the pst.
+  uint8_t pst_hash[SHA256_DIGEST_LENGTH];
+  int64_t time_of_license_received;
+  int64_t time_of_first_decrypt;
+  int64_t time_of_last_decrypt;
+  enum OEMCrypto_Usage_Entry_Status status;
+  uint8_t mac_key_server[wvcdm::MAC_KEY_SIZE];
+  uint8_t mac_key_client[wvcdm::MAC_KEY_SIZE];
+};
+typedef union {
+  struct StoredUsageEntry entry;
+  uint8_t padding[128];  // multiple of block size and bigger than entry size.
+} AlignedStoredUsageEntry;
+
+struct StoredUsageTable {
+  uint8_t signature[SHA256_DIGEST_LENGTH];
+  uint8_t iv[wvcdm::KEY_IV_SIZE];
+  int64_t generation;
+  size_t count;
+  AlignedStoredUsageEntry entries[];
+};
+
+class UsageTableEntry {
+ public:
+  UsageTableEntry(const std::vector<uint8_t> &pst_hash, SessionContext *ctx);
+  UsageTableEntry(const StoredUsageEntry *buffer);
+  ~UsageTableEntry();
+  void SaveToBuffer(StoredUsageEntry *buffer);
+  OEMCrypto_Usage_Entry_Status status() const { return status_; }
+  void Deactivate();
+  bool UpdateTime();
+  OEMCryptoResult ReportUsage(SessionContext *session,
+                              const std::vector<uint8_t> &pst,
+                              OEMCrypto_PST_Report *buffer,
+                              size_t *buffer_length);
+  // Set them if not set, verify if already set.
+  bool VerifyOrSetMacKeys(const std::vector<uint8_t> &server,
+                          const std::vector<uint8_t> &client);
+  const std::vector<uint8_t> &pst_hash() const { return pst_hash_; }
+  void set_session(SessionContext *session) { session_ = session; }
+
+ private:
+  std::vector<uint8_t> pst_hash_;
+  int64_t time_of_license_received_;
+  int64_t time_of_first_decrypt_;
+  int64_t time_of_last_decrypt_;
+  enum OEMCrypto_Usage_Entry_Status status_;
+  std::vector<uint8_t> mac_key_server_;
+  std::vector<uint8_t> mac_key_client_;
+
+  SessionContext *session_;
+  static wvcdm::Clock clock_;
+};
+
+class UsageTable {
+ public:
+  UsageTable(CryptoEngine *ce);
+  ~UsageTable() { Clear(); }
+  UsageTableEntry *FindEntry(const std::vector<uint8_t> &pst);
+  UsageTableEntry *CreateEntry(const std::vector<uint8_t> &pst,
+                               SessionContext *ctx);
+  OEMCryptoResult UpdateTable();
+  OEMCryptoResult DeactivateEntry(const std::vector<uint8_t> &pst);
+  bool DeleteEntry(const std::vector<uint8_t> &pst);
+  bool Clear();
+
+ private:
+  UsageTableEntry *FindEntryLocked(const std::vector<uint8_t> &pst);
+  bool SaveToFile();
+  bool ComputeHash(const std::vector<uint8_t> &pst,
+                   std::vector<uint8_t> &pst_hash);
+
+  typedef std::map<std::vector<uint8_t>, UsageTableEntry *> EntryMap;
+  EntryMap table_;
+  wvcdm::Lock lock_;
+  int64_t generation_;
+  CryptoEngine *ce_;
+};
+
+};  // namespace wvoec_mock
+
+#endif  // WVOEC_MOCK_OEMCRYPTO_USAGE_TABLE_MOCK_H_