commit 9c4e0fa92912a1fdd7235cd7ae108ad32fe5ea0f
author John W. Bruce <juce@google.com> Fri May 03 17:12:44 2019 -0700
committer John Bruce <juce@google.com> Wed May 08 01:08:07 2019 +0000
tree adb3d730bf0556913f249772caca6afd35900d0f
parent f95c698108b608e6ebf86e7450a9a2464e3ae264

Do Not Pass Blank App Package Name to MediaDrm Plugins

Previously, the NDK has always passed a blank app package name to the
MediaDrm plugins. However, some DRM systems need this value to be filled
in to operate correctly.

Unfortunately, since supplying or not supplying this value can
invalidate existing DRM licenses, we cannot start passing it in for
devices that might have previously run without it. As such, passing it
is only supported on devices for which Q is their first Android release.

Bug: 65680731
Test: CTS NativeMediaDrmClearkeyTest
Change-Id: Icccde9708766a86ccd352c82be25285fc9f8ebca

media/ndk/NdkMediaDrm.cpp

diff --git a/media/ndk/NdkMediaDrm.cpp b/media/ndk/NdkMediaDrm.cpp
index 2deb1a4..85dbffe 100644
--- a/media/ndk/NdkMediaDrm.cpp
+++ b/media/ndk/NdkMediaDrm.cpp
@@ -18,6 +18,7 @@
 #define LOG_TAG "NdkMediaDrm"
 
 #include <inttypes.h>
+#include <unistd.h>
 
 #include <media/NdkMediaDrm.h>
 
@@ -26,6 +27,8 @@
 #include <utils/StrongPointer.h>
 #include <gui/Surface.h>
 
+#include <android-base/properties.h>
+#include <binder/PermissionController.h>
 #include <media/IDrm.h>
 #include <media/IDrmClient.h>
 #include <media/stagefright/MediaErrors.h>
@@ -231,6 +234,39 @@
     return result;
 }
 
+static bool ShouldGetAppPackageName(void) {
+    // Check what this device's first API level was.
+    int32_t firstApiLevel = android::base::GetIntProperty<int32_t>("ro.product.first_api_level", 0);
+    if (firstApiLevel == 0) {
+        // First API Level is 0 on factory ROMs, but we can assume the current SDK
+        // version is the first if it's a factory ROM.
+        firstApiLevel = android::base::GetIntProperty<int32_t>("ro.build.version.sdk", 0);
+    }
+    return firstApiLevel >= 29;  // Android Q
+}
+
+static status_t GetAppPackageName(String8 *packageName) {
+    sp<IServiceManager> serviceManager = defaultServiceManager();
+    sp<IBinder> binder = serviceManager->getService(String16("permission"));
+
+    sp<IPermissionController> permissionContol = interface_cast<IPermissionController>(binder);
+    if (permissionContol == NULL) {
+        ALOGE("Failed to get permission service");
+        return UNKNOWN_ERROR;
+    }
+
+    Vector<String16> packages;
+    permissionContol->getPackagesForUid(getuid(), packages);
+
+    if (packages.isEmpty()) {
+        ALOGE("Unable to get package name for current UID");
+        return UNKNOWN_ERROR;
+    }
+
+    *packageName = String8(packages[0]);
+    return OK;
+}
+
 static sp<IDrm> CreateDrm() {
     sp<IServiceManager> sm = defaultServiceManager();
     sp<IBinder> binder = sm->getService(String16("media.drm"));
@@ -255,8 +291,16 @@
         return NULL;
     }
 
-    String8 nullPackageName;
-    status_t err = drm->createPlugin(uuid, nullPackageName);
+    String8 packageName;
+    if (ShouldGetAppPackageName()) {
+        status_t err = GetAppPackageName(&packageName);
+
+        if (err != OK) {
+            return NULL;
+        }
+    }
+
+    status_t err = drm->createPlugin(uuid, packageName);
 
     if (err != OK) {
         return NULL;