API council requested tweaks to TrafficStats.

Test: atest android.appsecurity.cts.AppSecurityTests#testAppFailAccessPrivateData
Bug: 71584606
Change-Id: I4be8a47d54a04f17cbaac735d543ff7d6370376d

4 files changed, 34 insertions, 9 deletions

diff --git a/api/current.txt b/api/current.txt
index 5e7fa591385e..26054ab057d7 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -27277,6 +27277,7 @@ package android.net {
     method public static long getMobileTxBytes();
     method public static long getMobileTxPackets();
     method public static int getThreadStatsTag();
+    method public static int getThreadStatsUid();
     method public static long getTotalRxBytes();
     method public static long getTotalRxPackets();
     method public static long getTotalTxBytes();
@@ -27296,7 +27297,7 @@ package android.net {
     method public static void incrementOperationCount(int);
     method public static void incrementOperationCount(int, int);
     method public static void setThreadStatsTag(int);
-    method public static void setThreadStatsUidSelf();
+    method public static void setThreadStatsUid(int);
     method public static void tagDatagramSocket(java.net.DatagramSocket) throws java.net.SocketException;
     method public static void tagFileDescriptor(java.io.FileDescriptor) throws java.io.IOException;
     method public static void tagSocket(java.net.Socket) throws java.net.SocketException;
diff --git a/api/removed.txt b/api/removed.txt
index 1228fd18c71a..64a9c3f6666b 100644
--- a/api/removed.txt
+++ b/api/removed.txt
@@ -261,6 +261,10 @@ package android.net {
     method public static deprecated org.apache.http.conn.ssl.SSLSocketFactory getHttpSocketFactory(int, android.net.SSLSessionCache);
   }
 
+  public class TrafficStats {
+    method public static deprecated void setThreadStatsUidSelf();
+  }
+
 }
 
 package android.os {
diff --git a/core/java/android/net/TrafficStats.java b/core/java/android/net/TrafficStats.java
index 7922276edb75..40d53b741d6b 100644
--- a/core/java/android/net/TrafficStats.java
+++ b/core/java/android/net/TrafficStats.java
@@ -16,7 +16,6 @@
 
 package android.net;
 
-import android.annotation.RequiresPermission;
 import android.annotation.SuppressLint;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
@@ -259,30 +258,47 @@ public class TrafficStats {
     /**
      * Set specific UID to use when accounting {@link Socket} traffic
      * originating from the current thread. Designed for use when performing an
-     * operation on behalf of another application.
+     * operation on behalf of another application, or when another application
+     * is performing operations on your behalf.
+     * <p>
+     * Any app can <em>accept</em> blame for traffic performed on a socket
+     * originally created by another app by calling this method with the
+     * {@link android.system.Os#getuid()} value. However, only apps holding the
+     * {@code android.Manifest.permission#UPDATE_DEVICE_STATS} permission may
+     * <em>assign</em> blame to another UIDs.
      * <p>
      * Changes only take effect during subsequent calls to
      * {@link #tagSocket(Socket)}.
-     * <p>
-     * To take effect, caller must hold
-     * {@link android.Manifest.permission#UPDATE_DEVICE_STATS} permission.
-     *
-     * @hide
      */
     @SystemApi
-    @RequiresPermission(android.Manifest.permission.UPDATE_DEVICE_STATS)
+    @SuppressLint("Doclava125")
     public static void setThreadStatsUid(int uid) {
         NetworkManagementSocketTagger.setThreadSocketStatsUid(uid);
     }
 
     /**
+     * Get the active UID used when accounting {@link Socket} traffic originating
+     * from the current thread. Only one active tag per thread is supported.
+     * {@link #tagSocket(Socket)}.
+     *
+     * @see #setThreadStatsUid(int)
+     */
+    public static int getThreadStatsUid() {
+        return NetworkManagementSocketTagger.getThreadSocketStatsUid();
+    }
+
+    /**
      * Set specific UID to use when accounting {@link Socket} traffic
      * originating from the current thread as the calling UID. Designed for use
      * when another application is performing operations on your behalf.
      * <p>
      * Changes only take effect during subsequent calls to
      * {@link #tagSocket(Socket)}.
+     *
+     * @removed
+     * @deprecated use {@link #setThreadStatsUid(int)} instead.
      */
+    @Deprecated
     public static void setThreadStatsUidSelf() {
         setThreadStatsUid(android.os.Process.myUid());
     }
diff --git a/core/java/com/android/server/NetworkManagementSocketTagger.java b/core/java/com/android/server/NetworkManagementSocketTagger.java
index 03f2bc10b551..2959667e046f 100644
--- a/core/java/com/android/server/NetworkManagementSocketTagger.java
+++ b/core/java/com/android/server/NetworkManagementSocketTagger.java
@@ -67,6 +67,10 @@ public final class NetworkManagementSocketTagger extends SocketTagger {
         return old;
     }
 
+    public static int getThreadSocketStatsUid() {
+        return threadSocketTags.get().statsUid;
+    }
+
     @Override
     public void tag(FileDescriptor fd) throws SocketException {
         final SocketTags options = threadSocketTags.get();