From 6d6cd68660635d670b0cb17f348b7c1da13704b3 Mon Sep 17 00:00:00 2001
From: Seigo Nonaka <nona@google.com>
Date: Thu, 22 Jun 2017 08:22:18 -0700
Subject: [PATCH] Stop loading other package's font by default.

Since CONTEXT_RESTRICTED is not a default flag of createPackageContext,
we can't rely on it for preventing unexpected font injections.
To protect developers and existing apps from a risk of font injection,
stop loading font from other package's resouce unless the developer
explicitly set CONTEXT_IGNORE_SECURITY.

Bug: 62813533
Bug: 62879353
Test: Manually done
Change-Id: I4442ddc48dadb5c968b444be86038b602074d301
---
 core/java/android/app/ContextImpl.java             | 8 ++++++++
 core/java/android/content/Context.java             | 6 ++++++
 core/java/android/content/ContextWrapper.java      | 6 ++++++
 core/java/android/widget/TextView.java             | 6 +++---
 test-runner/src/android/test/mock/MockContext.java | 6 ++++++
 5 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/core/java/android/app/ContextImpl.java b/core/java/android/app/ContextImpl.java
index a040520ffb9fb..318c7ac315228 100644
--- a/core/java/android/app/ContextImpl.java
+++ b/core/java/android/app/ContextImpl.java
@@ -2156,6 +2156,14 @@ class ContextImpl extends Context {
         return (mFlags & Context.CONTEXT_CREDENTIAL_PROTECTED_STORAGE) != 0;
     }
 
+    @Override
+    public boolean canLoadUnsafeResources() {
+        if (getPackageName().equals(getOpPackageName())) {
+            return true;
+        }
+        return (mFlags & Context.CONTEXT_IGNORE_SECURITY) != 0;
+    }
+
     @Override
     public Display getDisplay() {
         if (mDisplay == null) {
diff --git a/core/java/android/content/Context.java b/core/java/android/content/Context.java
index 5929aca0a38f4..ef6170359dda2 100644
--- a/core/java/android/content/Context.java
+++ b/core/java/android/content/Context.java
@@ -4680,6 +4680,12 @@ public abstract class Context {
     @SystemApi
     public abstract boolean isCredentialProtectedStorage();
 
+    /**
+     * Returns true if the context can load unsafe resources, e.g. fonts.
+     * @hide
+     */
+    public abstract boolean canLoadUnsafeResources();
+
     /**
      * @hide
      */
diff --git a/core/java/android/content/ContextWrapper.java b/core/java/android/content/ContextWrapper.java
index c719c6474cf16..a9fd58bc950ce 100644
--- a/core/java/android/content/ContextWrapper.java
+++ b/core/java/android/content/ContextWrapper.java
@@ -925,6 +925,12 @@ public class ContextWrapper extends Context {
         return mBase.isCredentialProtectedStorage();
     }
 
+    /** {@hide} */
+    @Override
+    public boolean canLoadUnsafeResources() {
+        return mBase.canLoadUnsafeResources();
+    }
+
     /**
      * @hide
      */
diff --git a/core/java/android/widget/TextView.java b/core/java/android/widget/TextView.java
index 6b328ea019979..9a924890fcd7e 100644
--- a/core/java/android/widget/TextView.java
+++ b/core/java/android/widget/TextView.java
@@ -913,7 +913,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                         break;
 
                     case com.android.internal.R.styleable.TextAppearance_fontFamily:
-                        if (!context.isRestricted()) {
+                        if (!context.isRestricted() && context.canLoadUnsafeResources()) {
                             try {
                                 fontTypeface = appearance.getFont(attr);
                             } catch (UnsupportedOperationException
@@ -1233,7 +1233,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                     break;
 
                 case com.android.internal.R.styleable.TextView_fontFamily:
-                    if (!context.isRestricted()) {
+                    if (!context.isRestricted() && context.canLoadUnsafeResources()) {
                         try {
                             fontTypeface = a.getFont(attr);
                         } catch (UnsupportedOperationException | Resources.NotFoundException e) {
@@ -3417,7 +3417,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
 
         Typeface fontTypeface = null;
         String fontFamily = null;
-        if (!context.isRestricted()) {
+        if (!context.isRestricted() && context.canLoadUnsafeResources()) {
             try {
                 fontTypeface = ta.getFont(R.styleable.TextAppearance_fontFamily);
             } catch (UnsupportedOperationException | Resources.NotFoundException e) {
diff --git a/test-runner/src/android/test/mock/MockContext.java b/test-runner/src/android/test/mock/MockContext.java
index ebad81cdda348..5e5ba462cfca2 100644
--- a/test-runner/src/android/test/mock/MockContext.java
+++ b/test-runner/src/android/test/mock/MockContext.java
@@ -814,6 +814,12 @@ public class MockContext extends Context {
         throw new UnsupportedOperationException();
     }
 
+    /** {@hide} */
+    @Override
+    public boolean canLoadUnsafeResources() {
+        throw new UnsupportedOperationException();
+    }
+
     /** {@hide} */
     @Override
     public IBinder getActivityToken() {