commit 700342fb8cc3d170236783fc1faeceec1ccd067f
author Galia Peycheva <galinap@google.com> Tue Jan 12 19:59:51 2021 +0100
committer Galia Peycheva <galinap@google.com> Tue Jan 12 21:00:03 2021 +0100
tree 3700e42798336e2c8654e821c3717f167bcdf950
parent 7b632a57ee3f4a236575a62bb6fb7c3ab91c4f65

Add permission check for blurs in SurfaceFlinger

This CL checks that original calling package for background blur and
blur regions has the Manifest.permission.USE_BACKGROUND_BLUR permission.

Bug: 177336952
Test: manual
Change-Id: I70d1e17158d83cc87f73be6f3a2f39d173c01149

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 63201b0..8331646 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -276,6 +276,7 @@
 const String16 sAccessSurfaceFlinger("android.permission.ACCESS_SURFACE_FLINGER");
 const String16 sRotateSurfaceFlinger("android.permission.ROTATE_SURFACE_FLINGER");
 const String16 sReadFramebuffer("android.permission.READ_FRAME_BUFFER");
+const String16 sUseBackgroundBlur("android.permission.USE_BACKGROUND_BLUR");
 const String16 sDump("android.permission.DUMP");
 const char* KERNEL_IDLE_TIMER_PROP = "graphics.display.kernel_idle_timer.enabled";
 
@@ -333,6 +334,10 @@
             PermissionCache::checkPermission(sRotateSurfaceFlinger, pid, uid);
 }
 
+bool originalCallerCanUseBlurs(int originPid, int originUid) {
+    return PermissionCache::checkPermission(sUseBackgroundBlur, originPid, originUid);
+}
+
 SurfaceFlingerBE::SurfaceFlingerBE() : mHwcServiceName(getHwcServiceName()) {}
 
 SurfaceFlinger::SurfaceFlinger(Factory& factory, SkipInitializationTag)
@@ -3436,9 +3441,10 @@
     std::unordered_set<ListenerCallbacks, ListenerCallbacksHash> listenerCallbacksWithSurfaces;
     uint32_t clientStateFlags = 0;
     for (const ComposerState& state : states) {
-        clientStateFlags |= setClientStateLocked(frameTimelineVsyncId, state, desiredPresentTime,
-                                                 isAutoTimestamp, postTime, privileged,
-                                                 listenerCallbacksWithSurfaces);
+        clientStateFlags |=
+                setClientStateLocked(frameTimelineVsyncId, state, desiredPresentTime,
+                                     isAutoTimestamp, postTime, privileged,
+                                     listenerCallbacksWithSurfaces, originPid, originUid);
         if ((flags & eAnimation) && state.state.surface) {
             if (const auto layer = fromHandleLocked(state.state.surface).promote(); layer) {
                 mScheduler->recordLayerHistory(layer.get(),
@@ -3618,7 +3624,8 @@
 uint32_t SurfaceFlinger::setClientStateLocked(
         int64_t frameTimelineVsyncId, const ComposerState& composerState,
         int64_t desiredPresentTime, bool isAutoTimestamp, int64_t postTime, bool privileged,
-        std::unordered_set<ListenerCallbacks, ListenerCallbacksHash>& listenerCallbacks) {
+        std::unordered_set<ListenerCallbacks, ListenerCallbacksHash>& listenerCallbacks,
+        int originPid, int originUid) {
     const layer_state_t& s = composerState.state;
 
     for (auto& listener : s.listeners) {
@@ -3762,10 +3769,14 @@
         if (layer->setCornerRadius(s.cornerRadius))
             flags |= eTraversalNeeded;
     }
-    if (what & layer_state_t::eBackgroundBlurRadiusChanged && !mDisableBlurs && mSupportsBlur) {
+
+    if (what & layer_state_t::eBackgroundBlurRadiusChanged && !mDisableBlurs && mSupportsBlur &&
+        originalCallerCanUseBlurs(originPid, originUid)) {
         if (layer->setBackgroundBlurRadius(s.backgroundBlurRadius)) flags |= eTraversalNeeded;
     }
-    if (what & layer_state_t::eBlurRegionsChanged) {
+
+    if (what & layer_state_t::eBlurRegionsChanged &&
+        originalCallerCanUseBlurs(originPid, originUid)) {
         if (layer->setBlurRegions(s.blurRegions)) flags |= eTraversalNeeded;
     }
     if (what & layer_state_t::eLayerStackChanged) {

services/surfaceflinger/SurfaceFlinger.h

diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 9f0f2ea..67cf464 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -342,8 +342,8 @@
     virtual uint32_t setClientStateLocked(
             int64_t frameTimelineVsyncId, const ComposerState& composerState,
             int64_t desiredPresentTime, bool isAutoTimestamp, int64_t postTime, bool privileged,
-            std::unordered_set<ListenerCallbacks, ListenerCallbacksHash>& listenerCallbacks)
-            REQUIRES(mStateLock);
+            std::unordered_set<ListenerCallbacks, ListenerCallbacksHash>& listenerCallbacks,
+            int originPid, int originUid) REQUIRES(mStateLock);
     virtual void commitTransactionLocked();
 
     // Used internally by computeLayerBounds() to gets the clip rectangle to use for the