Fixed race condition in closeSession

Merged from http://go/wvgerrit/165498
poc: http://go/ag/20978761

Fix race that corrupts mCryptoSessions std::map,
and race that occurs when CryptoSessions are used after free.

Test: poc
Test: atest MediaDrmParameterizedTests
Test: atest GtsMediaTestCases

Bug: 258189255
Change-Id: I298d3e0770ace9cd590dfaacaa4c52a0732c2fe3
Merged-In: I298d3e0770ace9cd590dfaacaa4c52a0732c2fe3

libwvdrmengine/mediadrm/include_hidl/WVDrmPlugin.h

@@ -8,6 +8,7 @@
 #define WV_DRM_PLUGIN_H_
 
 #include <map>
+#include <mutex>
 
 #include "cdm_client_property_set.h"
 #include "cdm_identifier.h"
@@ -450,9 +451,46 @@ struct WVDrmPlugin : public ::drm::V1_4::IDrmPlugin, IDrmPluginListener,
     uint32_t getNextUniqueId();
   } mCdmIdentifierBuilder;
 
+  class CryptoSessionMap {
+   public:
+    std::map<CdmSessionId, std::shared_ptr<CryptoSession>> clear() {
+      std::unique_lock<std::mutex> auto_lock(mLock);
+      auto copy = mMap;
+      mMap.clear();
+      return copy;
+    }
+
+    std::shared_ptr<CryptoSession> get(const CdmSessionId& sid) {
+      std::unique_lock<std::mutex> auto_lock(mLock);
+      if (mMap.count(sid)) {
+        return mMap[sid];
+      }
+      return nullptr;
+    }
+
+    bool empty() {
+      std::unique_lock<std::mutex> auto_lock(mLock);
+      return mMap.empty();
+    }
+
+    void erase(const CdmSessionId& sid) {
+      std::unique_lock<std::mutex> auto_lock(mLock);
+      mMap.erase(sid);
+    }
+
+    void insert(const CdmSessionId& sid, OEMCrypto_SESSION osid) {
+      std::unique_lock<std::mutex> auto_lock(mLock);
+      mMap[sid] = std::make_shared<CryptoSession>(osid);
+    }
+
+   private:
+     std::mutex mLock;
+     std::map<CdmSessionId, std::shared_ptr<CryptoSession>> mMap;
+  };
+
   sp<wvcdm::WvContentDecryptionModule> const mCDM;
   WVGenericCryptoInterface* mCrypto;
-  map<CdmSessionId, CryptoSession> mCryptoSessions;
+  CryptoSessionMap mCryptoSessions;
   sp<IDrmPluginListener> mListener;
   sp<IDrmPluginListener_V1_2> mListenerV1_2;