Merge "Fix WVCryptoPlugin use after free vulnerability." into sc-dev am: 9d1ad7590a

Original change: https://googleplex-android-review.googlesource.com/c/platform/vendor/widevine/+/13808139

Change-Id: I4c2aadb7b98c48abc349582d0bca0ddb41d05df7

libwvdrmengine/mediacrypto/Android.bp

@@ -102,6 +102,8 @@ cc_library_static {
         "liblog",
     ],
 
+    cflags: ["-Wthread-safety"],
+
     proprietary: true,
 
 }

libwvdrmengine/mediacrypto/include_hidl/WVCryptoPlugin.h

@@ -7,8 +7,11 @@
 #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 "log.h"
 #include "wv_content_decryption_module.h"
@@ -60,7 +63,7 @@ struct WVCryptoPlugin : public ::drm::V1_4::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
 
   Return<void> getLogMessages(
       getLogMessages_cb _hidl_cb) override;
@@ -73,7 +76,7 @@ struct WVCryptoPlugin : public ::drm::V1_4::ICryptoPlugin {
   wvcdm::LoggingUidSetter mLoggingUidSetter;
 
   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;
   uint32_t mUserId;
@@ -81,6 +84,8 @@ struct WVCryptoPlugin : public ::drm::V1_4::ICryptoPlugin {
   Status_V1_2 attemptDecrypt(
       const wvcdm::CdmDecryptionParametersV16& params,
       bool haveEncryptedSubsamples, std::string* errorDetailMsg);
+
+  std::mutex mSharedBufferLock;
 };
 
 }  // namespace widevine

libwvdrmengine/mediacrypto/src_hidl/WVCryptoPlugin.cpp

@@ -121,6 +121,8 @@ 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();
@@ -169,7 +171,7 @@ 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");
@@ -245,6 +247,9 @@ 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;