[RESTRICT AUTOMERGE] Fix WVCryptoPlugin use after free vulnerability. am: 76f39ddb08 am: 2c59c30f1b

Original change: https://googleplex-android-review.googlesource.com/c/platform/vendor/widevine/+/13499847

Change-Id: I9d84f4bc553f9c665d418734a9cf032bb4460a0c

libwvdrmengine/mediacrypto/Android.mk

@@ -78,6 +78,8 @@ LOCAL_SHARED_LIBRARIES := \
   libhidlmemory \
   liblog
 
+LOCAL_CFLAGS := -Wthread-safety
+
 LOCAL_MODULE := libwvdrmcryptoplugin_hidl
 LOCAL_LICENSE_KINDS := legacy_by_exception_only
 LOCAL_LICENSE_CONDITIONS := by_exception_only

libwvdrmengine/mediacrypto/include_hidl/WVCryptoPlugin.h

@@ -7,11 +7,14 @@
 #ifndef WV_CRYPTO_PLUGIN_H_
 #define WV_CRYPTO_PLUGIN_H_
 
+#include <android-base/thread_annotations.h>
 #include <android/hidl/memory/1.0/IMemory.h>
 
+#include <mutex>
+
 #include "HidlTypes.h"
-#include "wv_content_decryption_module.h"
 #include "WVTypes.h"
+#include "wv_content_decryption_module.h"
 
 namespace wvdrm {
 namespace hardware {
@@ -59,19 +62,21 @@ struct WVCryptoPlugin : public ICryptoPlugin {
       const SharedBuffer& source,
       uint64_t offset,
       const DestinationBuffer& destination,
-      decrypt_1_2_cb _hidl_cb) override;
+      decrypt_1_2_cb _hidl_cb) override  NO_THREAD_SAFETY_ANALYSIS; // use unique_lock
 
  private:
   WVDRM_DISALLOW_COPY_AND_ASSIGN_AND_NEW(WVCryptoPlugin);
 
   wvcdm::CdmSessionId mSessionId;
-  std::map<uint32_t, sp<IMemory> > mSharedBufferMap;
+  std::map<uint32_t, sp<IMemory> > mSharedBufferMap GUARDED_BY(mSharedBufferLock);
 
   sp<wvcdm::WvContentDecryptionModule> const mCDM;
 
   Status_V1_2 attemptDecrypt(
       const wvcdm::CdmDecryptionParametersV16& params,
       bool haveEncryptedSubsamples, std::string* errorDetailMsg);
+
+  std::mutex mSharedBufferLock;
 };
 
 }  // namespace widevine

libwvdrmengine/mediacrypto/src_hidl/WVCryptoPlugin.cpp

@@ -110,6 +110,8 @@ Return<void> WVCryptoPlugin::setSharedBufferBase(
     const hidl_memory& base, uint32_t bufferId) {
   sp<IMemory> hidlMemory = mapMemory(base);
 
+  std::lock_guard<std::mutex> shared_buffer_lock(mSharedBufferLock);
+
   // allow mapMemory to return nullptr
   mSharedBufferMap[bufferId] = hidlMemory;
   return Void();
@@ -158,7 +160,7 @@ Return<void> WVCryptoPlugin::decrypt_1_2(
     uint64_t offset,
     const DestinationBuffer& destination,
     decrypt_1_2_cb _hidl_cb) {
-
+  std::unique_lock<std::mutex> lock(mSharedBufferLock);
   if (mSharedBufferMap.find(source.bufferId) == mSharedBufferMap.end()) {
     _hidl_cb(Status_V1_2::ERROR_DRM_CANNOT_HANDLE, 0,
              "source decrypt buffer base not set");
@@ -231,6 +233,9 @@ Return<void> WVCryptoPlugin::decrypt_1_2(
     destPtr = static_cast<void *>(handle);
   }
 
+  // release mSharedBufferLock
+  lock.unlock();
+
   // Set up the decrypt params
   CdmDecryptionParametersV16 params;
   params.key_id = cryptoKey;