Check /dev/binder access before calling defaultServiceManager()

am: 41b7c70821

Change-Id: Idfe934eb2e7339b7bfbbd4fbfaacbcce670baf72

1 files changed, 5 insertions, 0 deletions

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 android {
 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);