Fix for heap-use-after-free in GPUService.cpp

This adds a unit test and fix for the bug reported by libfuzzer.
Changes made:
 * Expose GPUService as testable code.
 * Update main_gpuservice.cpp to use the new GpuService now located at
   gpuservice/GpuService.h
 * Make initializer threads members of GpuService
 * Join the threads in destructor to prevent heap-use-after-free.
 * Add unit test that waits 3 seconds after deallocation to ensure no
   wrong access is made.

Bug: 282919145
Test: Added unit test and ran on device with ASAN
(cherry picked from commit 3c00cbc)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:7fb707802ee4c667d1ee6065ae2845d835b47aeb)
Merged-In: I4d1d2d4658b575bf2c8f425f91f68f03114ad029
Change-Id: I4d1d2d4658b575bf2c8f425f91f68f03114ad029

services/gpuservice/Android.bp

@@ -71,6 +71,7 @@ filegroup {
 cc_library_shared {
     name: "libgpuservice",
     defaults: ["libgpuservice_production_defaults"],
+    export_include_dirs: ["include"],
     srcs: [
         ":libgpuservice_sources",
     ],

services/gpuservice/GpuService.cpp

@@ -16,7 +16,7 @@
 
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
 
-#include "GpuService.h"
+#include "gpuservice/GpuService.h"
 
 #include <android-base/stringprintf.h>
 #include <binder/IPCThreadState.h>
@@ -34,6 +34,7 @@
 #include <vkjson.h>
 
 #include <thread>
+#include <memory>
 
 namespace android {
 
@@ -55,18 +56,21 @@ GpuService::GpuService()
         mGpuStats(std::make_unique<GpuStats>()),
         mGpuMemTracer(std::make_unique<GpuMemTracer>()) {
 
-    std::thread gpuMemAsyncInitThread([this]() {
+    mGpuMemAsyncInitThread = std::make_unique<std::thread>([this] (){
         mGpuMem->initialize();
         mGpuMemTracer->initialize(mGpuMem);
     });
-    gpuMemAsyncInitThread.detach();
 
-    std::thread gpuWorkAsyncInitThread([this]() {
+    mGpuWorkAsyncInitThread = std::make_unique<std::thread>([this]() {
         mGpuWork->initialize();
     });
-    gpuWorkAsyncInitThread.detach();
 };
 
+GpuService::~GpuService() {
+    mGpuWorkAsyncInitThread->join();
+    mGpuMemAsyncInitThread->join();
+}
+
 void GpuService::setGpuStats(const std::string& driverPackageName,
                              const std::string& driverVersionName, uint64_t driverVersionCode,
                              int64_t driverBuildTime, const std::string& appPackageName,

services/gpuservice/GpuService.h → services/gpuservice/include/gpuservice/GpuService.h

@@ -24,6 +24,7 @@
 #include <serviceutils/PriorityDumper.h>
 
 #include <mutex>
+#include <thread>
 #include <vector>
 
 namespace android {
@@ -41,6 +42,7 @@ class GpuService : public BnGpuService, public PriorityDumper {
     static const char* const SERVICE_NAME ANDROID_API;
 
     GpuService() ANDROID_API;
+    ~GpuService();
 
 protected:
     status_t shellCommand(int in, int out, int err, std::vector<String16>& args) override;
@@ -86,6 +88,8 @@ class GpuService : public BnGpuService, public PriorityDumper {
     std::unique_ptr<GpuMemTracer> mGpuMemTracer;
     std::mutex mLock;
     std::string mDeveloperDriverPath;
+    std::unique_ptr<std::thread> mGpuMemAsyncInitThread;
+    std::unique_ptr<std::thread> mGpuWorkAsyncInitThread;
 };
 
 } // namespace android

services/gpuservice/main_gpuservice.cpp

@@ -18,7 +18,7 @@
 #include <binder/IServiceManager.h>
 #include <binder/ProcessState.h>
 #include <sys/resource.h>
-#include "GpuService.h"
+#include "gpuservice/GpuService.h"
 
 using namespace android;
 

services/gpuservice/tests/unittests/Android.bp

@@ -31,6 +31,7 @@ cc_test {
         "GpuMemTest.cpp",
         "GpuMemTracerTest.cpp",
         "GpuStatsTest.cpp",
+        "GpuServiceTest.cpp",
     ],
     header_libs: ["bpf_headers"],
     shared_libs: [
@@ -47,6 +48,7 @@ cc_test {
         "libstatslog",
         "libstatspull",
         "libutils",
+        "libgpuservice",
     ],
     static_libs: [
         "libgmock",

services/gpuservice/tests/unittests/GpuServiceTest.cpp

@@ -0,0 +1,52 @@
+#undef LOG_TAG
+#define LOG_TAG "gpuservice_unittest"
+
+#include "gpuservice/GpuService.h"
+
+#include <gtest/gtest.h>
+#include <log/log_main.h>
+
+#include <chrono>
+#include <thread>
+
+namespace android {
+namespace {
+
+class GpuServiceTest : public testing::Test {
+public:
+    GpuServiceTest() {
+        const ::testing::TestInfo* const test_info =
+                ::testing::UnitTest::GetInstance()->current_test_info();
+        ALOGD("**** Setting up for %s.%s\n", test_info->test_case_name(), test_info->name());
+    }
+
+    ~GpuServiceTest() {
+        const ::testing::TestInfo* const test_info =
+            ::testing::UnitTest::GetInstance()->current_test_info();
+        ALOGD("**** Tearing down after %s.%s\n", test_info->test_case_name(), test_info->name());
+    }
+
+};
+
+
+/*
+* The behaviour before this test + fixes was UB caused by threads accessing deallocated memory.
+*
+* This test creates the service (which initializes the culprit threads),
+* deallocates it immediately and sleeps.
+*
+* GpuService's destructor gets called and joins the threads.
+* If we haven't crashed by the time the sleep time has elapsed, we're good
+* Let the test pass.
+*/
+TEST_F(GpuServiceTest, onInitializeShouldNotCauseUseAfterFree) {
+    sp<GpuService> service = new GpuService();
+    service.clear();
+    std::this_thread::sleep_for(std::chrono::seconds(3));
+
+    // If we haven't crashed yet due to threads accessing freed up memory, let the test pass
+    EXPECT_TRUE(true);
+}
+
+} // namespace
+} // namespace android