commit 1ab425f1358e7c302296cb0bf65c3aadd4cbbd56
author Tri Vo <trong@google.com> Mon Mar 25 10:48:48 2019 -0700
committer android-build-merger <android-build-merger@google.com> Mon Mar 25 10:48:48 2019 -0700
tree f4f018d7160aeed26de6c6647023269b99a68626
parent 5b8024f3a484203650c3065e68391a6b26a265ab
parent 5e682c2851eb5951d08083b5ee7acde2537f473d

Check /dev/binder access before calling defaultServiceManager() am: 41b7c70821
am: 5e682c2851

Change-Id: Iaa776c7824bd4986d5618d2d5f2208ca023a5e99

ashmemd_client.cpp

diff --git a/ashmemd_client.cpp b/ashmemd_client.cpp
index 3380209..04227ba 100644
--- a/ashmemd_client.cpp
+++ b/ashmemd_client.cpp
@@ -28,6 +28,11 @@
 namespace ashmemd {
 
 sp<IAshmemDeviceService> getAshmemService() {
+    // Calls to defaultServiceManager() crash the process if it doesn't have appropriate
+    // binder permissions. Check these permissions proactively.
+    if (access("/dev/binder", R_OK | W_OK) != 0) {
+        return nullptr;
+    }
     sp<IServiceManager> sm = android::defaultServiceManager();
     sp<IBinder> binder = sm->checkService(String16("ashmem_device_service"));
     return interface_cast<IAshmemDeviceService>(binder);