From 07bb4de0427047076ba54ce2b2dd4eb32759e840 Mon Sep 17 00:00:00 2001
From: Rahul Frias <rfrias@google.com>
Date: Fri, 13 Apr 2018 01:12:16 -0700
Subject: [PATCH] Prevent race conditions between decrypt and close session

[ Merge of http://go/wvgerrit/47520 ]

Bug: 73781703
Test: WV unit/integration tests, GTS GtsMediaTestCases tests and AUPT tests.
Change-Id: I618ed8ca38855aecdb31e829a7f4041cbd505a02
---
 libwvdrmengine/cdm/core/include/cdm_session.h  |  5 ++++-
 libwvdrmengine/cdm/core/include/wv_cdm_types.h |  1 +
 libwvdrmengine/cdm/core/src/cdm_session.cpp    | 11 ++++++++++-
 libwvdrmengine/cdm/core/test/test_printers.cpp |  2 ++
 libwvdrmengine/include/mapErrors-inl.h         |  1 +
 libwvdrmengine/include_hidl/mapErrors-inl.h    |  1 +
 6 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/libwvdrmengine/cdm/core/include/cdm_session.h b/libwvdrmengine/cdm/core/include/cdm_session.h
index 113c9e96..854f459d 100644
--- a/libwvdrmengine/cdm/core/include/cdm_session.h
+++ b/libwvdrmengine/cdm/core/include/cdm_session.h
@@ -37,7 +37,7 @@ class CdmSession {
   CdmSession(FileSystem* file_system, metrics::SessionMetrics* metrics);
   virtual ~CdmSession();
 
-  void Close() { closed_ = true; }
+  void Close();
   bool IsClosed() { return closed_; }
 
   // Initializes this instance of CdmSession with the given property set.
@@ -263,6 +263,9 @@ class CdmSession {
   bool mock_license_parser_in_use_;
   bool mock_policy_engine_in_use_;
 
+  // Lock to avoid race conditions between Close() and Decrypt()
+  Lock close_lock_;
+
   CORE_DISALLOW_COPY_AND_ASSIGN(CdmSession);
 };
 
diff --git a/libwvdrmengine/cdm/core/include/wv_cdm_types.h b/libwvdrmengine/cdm/core/include/wv_cdm_types.h
index bead3941..19fc6310 100644
--- a/libwvdrmengine/cdm/core/include/wv_cdm_types.h
+++ b/libwvdrmengine/cdm/core/include/wv_cdm_types.h
@@ -333,6 +333,7 @@ enum CdmResponseType {
   GET_PROVISIONING_METHOD_ERROR = 289,
   SESSION_NOT_FOUND_17 = 290,
   SESSION_NOT_FOUND_18 = 291,
+  SESSION_CLOSED_1 = 292,
 };
 
 enum CdmKeyStatus {
diff --git a/libwvdrmengine/cdm/core/src/cdm_session.cpp b/libwvdrmengine/cdm/core/src/cdm_session.cpp
index f66ae08d..26267110 100644
--- a/libwvdrmengine/cdm/core/src/cdm_session.cpp
+++ b/libwvdrmengine/cdm/core/src/cdm_session.cpp
@@ -66,6 +66,11 @@ CdmSession::~CdmSession() {
   }
 }
 
+void CdmSession::Close() {
+  AutoLock lock(close_lock_);
+  closed_ = true;
+}
+
 CdmResponseType CdmSession::Init(
     CdmClientPropertySet* cdm_client_property_set) {
   return Init(cdm_client_property_set, NULL, NULL);
@@ -567,10 +572,14 @@ CdmResponseType CdmSession::QueryOemCryptoSessionId(
 // Decrypt() - Accept encrypted buffer and return decrypted data.
 CdmResponseType CdmSession::Decrypt(const CdmDecryptionParameters& params) {
   if (!initialized_) {
-    LOGE("CdmSession::Decrypt: not initialized");
     return NOT_INITIALIZED_ERROR;
   }
 
+  AutoLock lock(close_lock_);
+  if (IsClosed()) {
+    return SESSION_CLOSED_1;
+  }
+
   // Playback may not begin until either the start time passes or the license
   // is updated, so we treat this Decrypt call as invalid.
   if (params.is_encrypted) {
diff --git a/libwvdrmengine/cdm/core/test/test_printers.cpp b/libwvdrmengine/cdm/core/test/test_printers.cpp
index 475c5f89..0dc40bf6 100644
--- a/libwvdrmengine/cdm/core/test/test_printers.cpp
+++ b/libwvdrmengine/cdm/core/test/test_printers.cpp
@@ -599,6 +599,8 @@ void PrintTo(const enum CdmResponseType& value, ::std::ostream* os) {
       break;
     case SESSION_NOT_FOUND_18: *os << "SESSION_NOT_FOUND_18";
       break;
+    case SESSION_CLOSED_1: *os << "SESSION_CLOSED_1";
+      break;
     default:
       *os                                        << "Unknown CdmResponseType";
       break;
diff --git a/libwvdrmengine/include/mapErrors-inl.h b/libwvdrmengine/include/mapErrors-inl.h
index 029c11d9..8ebc454a 100644
--- a/libwvdrmengine/include/mapErrors-inl.h
+++ b/libwvdrmengine/include/mapErrors-inl.h
@@ -230,6 +230,7 @@ static android::status_t mapCdmResponseType(wvcdm::CdmResponseType res) {
     case wvcdm::SESSION_NOT_FOUND_10:
     case wvcdm::SESSION_NOT_FOUND_17:
     case wvcdm::SESSION_NOT_FOUND_18:
+    case wvcdm::SESSION_CLOSED_1:
         return android::ERROR_DRM_SESSION_NOT_OPENED;
     case wvcdm::SESSION_KEYS_NOT_FOUND:
       return kSessionKeysNotFound;
diff --git a/libwvdrmengine/include_hidl/mapErrors-inl.h b/libwvdrmengine/include_hidl/mapErrors-inl.h
index 1637e626..18503efb 100644
--- a/libwvdrmengine/include_hidl/mapErrors-inl.h
+++ b/libwvdrmengine/include_hidl/mapErrors-inl.h
@@ -58,6 +58,7 @@ static Status mapCdmResponseType(wvcdm::CdmResponseType res) {
     case wvcdm::SESSION_NOT_FOUND_10:
     case wvcdm::SESSION_NOT_FOUND_17:
     case wvcdm::SESSION_NOT_FOUND_18:
+    case wvcdm::SESSION_CLOSED_1:
       return Status::ERROR_DRM_SESSION_NOT_OPENED;
 
     case wvcdm::DECRYPT_ERROR: