From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Pranav Madapurmath <pmadapurmath@google.com>
Date: Thu, 25 May 2023 21:58:19 +0000
Subject: [PATCH] Resolve StatusHints image exploit across user.

Because of the INTERACT_ACROSS_USERS permission, an app that implements
a ConnectionService can upload an image icon belonging to another user
by setting it in the StatusHints. Validating the construction of the
StatusHints on the calling user would prevent a malicious app from
registering a connection service with the embedded image icon from a
different user.

From additional feedback, this CL also addresses potential
vulnerabilities in an app being able to directly invoke the binder for a
means to manipulate the contents of the bundle that are passed with it.
The targeted points of entry are in ConnectionServiceWrapper for the
following APIs: handleCreateConnectionComplete, setStatusHints,
addConferenceCall, and addExistingConnection.

Fixes: 280797684
Test: Manual (verified that original exploit is no longer an issue).
Test: Unit test for validating image in StatusHints constructor.
Test: Unit tests to address vulnerabilities via the binder.
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:48223d6034907349c6a3fab3018c1b37d86367af)
Merged-In: I6e70e238b3a5ace1cab41ec5796a6bb4d79769f2
Change-Id: I6e70e238b3a5ace1cab41ec5796a6bb4d79769f2
---
 .../java/android/telecom/StatusHints.java     | 53 ++++++++++++++++++-
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/telecomm/java/android/telecom/StatusHints.java b/telecomm/java/android/telecom/StatusHints.java
index 453f408bedba..c75bd2781f9f 100644
--- a/telecomm/java/android/telecom/StatusHints.java
+++ b/telecomm/java/android/telecom/StatusHints.java
@@ -16,14 +16,19 @@
 
 package android.telecom;
 
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.content.ComponentName;
 import android.content.Context;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.Icon;
+import android.os.Binder;
 import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.os.UserHandle;
+
+import com.android.internal.annotations.VisibleForTesting;
 
 import java.util.Objects;
 
@@ -33,7 +38,7 @@ import java.util.Objects;
 public final class StatusHints implements Parcelable {
 
     private final CharSequence mLabel;
-    private final Icon mIcon;
+    private Icon mIcon;
     private final Bundle mExtras;
 
     /**
@@ -48,10 +53,30 @@ public final class StatusHints implements Parcelable {
 
     public StatusHints(CharSequence label, Icon icon, Bundle extras) {
         mLabel = label;
-        mIcon = icon;
+        mIcon = validateAccountIconUserBoundary(icon, Binder.getCallingUserHandle());
         mExtras = extras;
     }
 
+    /**
+     * @param icon
+     * @hide
+     */
+    @VisibleForTesting
+    public StatusHints(@Nullable Icon icon) {
+        mLabel = null;
+        mExtras = null;
+        mIcon = icon;
+    }
+
+    /**
+     *
+     * @param icon
+     * @hide
+     */
+    public void setIcon(@Nullable Icon icon) {
+        mIcon = icon;
+    }
+
     /**
      * @return A package used to load the icon.
      *
@@ -112,6 +137,30 @@ public final class StatusHints implements Parcelable {
         return 0;
     }
 
+    /**
+     * Validates the StatusHints image icon to see if it's not in the calling user space.
+     * Invalidates the icon if so, otherwise returns back the original icon.
+     *
+     * @param icon
+     * @return icon (validated)
+     * @hide
+     */
+    public static Icon validateAccountIconUserBoundary(Icon icon, UserHandle callingUserHandle) {
+        // Refer to Icon#getUriString for context. The URI string is invalid for icons of
+        // incompatible types.
+        if (icon != null && (icon.getType() == Icon.TYPE_URI
+                /*|| icon.getType() == Icon.TYPE_URI_ADAPTIVE_BITMAP*/)) {
+            String encodedUser = icon.getUri().getEncodedUserInfo();
+            // If there is no encoded user, the URI is calling into the calling user space
+            if (encodedUser != null) {
+                int userId = Integer.parseInt(encodedUser);
+                // Do not try to save the icon if the user id isn't in the calling user space.
+                if (userId != callingUserHandle.getIdentifier()) return null;
+            }
+        }
+        return icon;
+    }
+
     @Override
     public void writeToParcel(Parcel out, int flags) {
         out.writeCharSequence(mLabel);