From 66380f768c0de8bde1f54ac6ab3f126b66928dad Mon Sep 17 00:00:00 2001
From: Jamie Gennis <jgennis@google.com>
Date: Thu, 7 Apr 2011 19:03:56 -0700
Subject: [PATCH] Stagefright: authenticate ANativeWindow.

This change adds a check to verify that the ANativeWindow to which
decoded video buffers are queued sends those buffers to SurfaceFlinger.
The check is done when the buffer content is flagged as protected.  This
change also adds an error in the case where protected buffers are
needed, but an ANativeWindow is not being used as the video destination.

Change-Id: I107c9082d65ef0de4a13594e9535a2053ad5161b
Bug: 4269240
---
 media/libstagefright/OMXCodec.cpp | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/media/libstagefright/OMXCodec.cpp b/media/libstagefright/OMXCodec.cpp
index a70f8681d1945..5d26fd5f72060 100644
--- a/media/libstagefright/OMXCodec.cpp
+++ b/media/libstagefright/OMXCodec.cpp
@@ -1593,6 +1593,11 @@ status_t OMXCodec::allocateBuffersOnPort(OMX_U32 portIndex) {
         return allocateOutputBuffersFromNativeWindow();
     }
 
+    if (mEnableGrallocUsageProtected && portIndex == kPortIndexOutput) {
+        LOGE("protected output buffers must be stent to an ANativeWindow");
+        return PERMISSION_DENIED;
+    }
+
     OMX_PARAM_PORTDEFINITIONTYPE def;
     InitOMXParams(&def);
     def.nPortIndex = portIndex;
@@ -1761,6 +1766,25 @@ status_t OMXCodec::allocateOutputBuffersFromNativeWindow() {
         usage |= GRALLOC_USAGE_PROTECTED;
     }
 
+    // Make sure to check whether either Stagefright or the video decoder
+    // requested protected buffers.
+    if (usage & GRALLOC_USAGE_PROTECTED) {
+        // Verify that the ANativeWindow sends images directly to
+        // SurfaceFlinger.
+        int queuesToNativeWindow = 0;
+        err = mNativeWindow->query(
+                mNativeWindow.get(), NATIVE_WINDOW_QUEUES_TO_WINDOW_COMPOSER,
+                &queuesToNativeWindow);
+        if (err != 0) {
+            LOGE("error authenticating native window: %d", err);
+            return err;
+        }
+        if (queuesToNativeWindow != 1) {
+            LOGE("native window could not be authenticated");
+            return PERMISSION_DENIED;
+        }
+    }
+
     LOGV("native_window_set_usage usage=0x%x", usage);
     err = native_window_set_usage(
             mNativeWindow.get(), usage | GRALLOC_USAGE_HW_TEXTURE | GRALLOC_USAGE_EXTERNAL_DISP);