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Commit 2da50cfe authored by Hall Liu's avatar Hall Liu
Browse files

Institute limit on PhoneStateListener 

Limit apps to 50 concurrently registered instances of PhoneStateListener
via TelephonyManager#listen

Test: atest CtsTelephonyTestCases:PhoneStateListenerTest#testListenerLimit
Bug: 151835251
Change-Id: I8486d86773a1e28b4018620c48003855dae75b9d
parent 5bb02f08

core/java/android/telephony/PhoneStateListener.java

+12 −0
Original line number Diff line number Diff line
@@ -64,6 +64,18 @@ public class PhoneStateListener { 
    private static final String LOG_TAG = "PhoneStateListener";

    private static final boolean DBG = false; // STOPSHIP if true





    /**

     * Limit on registrations of {@link PhoneStateListener}s on a per-pid

     * basis. When this limit is exceeded, any calls to {@link TelephonyManager#listen} will fail

     * with an {@link IllegalStateException}.

     *

     * {@link android.os.Process#PHONE_UID}, {@link android.os.Process#SYSTEM_UID}, and the uid that

     * TelephonyRegistry runs under are exempt from this limit.

     * @hide

     */

    public static final int PER_PID_REGISTRATION_LIMIT = 50;



    /**

     * Stop listening for updates.

     *

services/core/java/com/android/server/TelephonyRegistry.java

+26 −4
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ import android.os.Bundle; 
import android.os.Handler;

import android.os.IBinder;

import android.os.Message;

import android.os.Process;

import android.os.RemoteException;

import android.os.UserHandle;

import android.telephony.Annotation;
@@ -605,7 +606,7 @@ public class TelephonyRegistry extends ITelephonyRegistry.Stub { 
        synchronized (mRecords) {

            // register

            IBinder b = callback.asBinder();

            Record r = add(b);

            Record r = add(b, Binder.getCallingPid(), false);



            if (r == null) {

                return;
@@ -659,7 +660,7 @@ public class TelephonyRegistry extends ITelephonyRegistry.Stub { 
        synchronized (mRecords) {

            // register

            IBinder b = callback.asBinder();

            Record r = add(b);

            Record r = add(b, Binder.getCallingPid(), false);



            if (r == null) {

                return;
@@ -789,7 +790,11 @@ public class TelephonyRegistry extends ITelephonyRegistry.Stub { 
            synchronized (mRecords) {

                // register

                IBinder b = callback.asBinder();

                Record r = add(b);

                boolean shouldEnforceListenerLimit =

                        Binder.getCallingUid() != Process.SYSTEM_UID

                        && Binder.getCallingUid() != Process.PHONE_UID

                        && Binder.getCallingUid() != Process.myUid();

                Record r = add(b, Binder.getCallingPid(), shouldEnforceListenerLimit);



                if (r == null) {

                    return;
@@ -1084,18 +1089,35 @@ public class TelephonyRegistry extends ITelephonyRegistry.Stub { 
        return record.canReadCallLog() ? mCallIncomingNumber[phoneId] : "";

    }



    private Record add(IBinder binder) {

    private Record add(IBinder binder, int callingPid, boolean enforceLimit) {

        Record r;



        synchronized (mRecords) {

            final int N = mRecords.size();

            // While iterating through the records, keep track of how many we have from this pid.

            int numRecordsForPid = 0;

            for (int i = 0; i < N; i++) {

                r = mRecords.get(i);

                if (binder == r.binder) {

                    // Already existed.

                    return r;

                }

                if (r.callerPid == callingPid) {

                    numRecordsForPid++;

                }

            }

            // If we've exceeded the limit for registrations, log a warning and quit.

            if (enforceLimit && numRecordsForPid >= PhoneStateListener.PER_PID_REGISTRATION_LIMIT) {

                String errorMsg = "Pid " + callingPid + " has exceeded the number of permissible"

                        + "registered listeners. Ignoring request to add.";

                loge(errorMsg);

                throw new IllegalStateException(errorMsg);

            } else if (enforceLimit

                    && numRecordsForPid >= PhoneStateListener.PER_PID_REGISTRATION_LIMIT / 2) {

                Rlog.w(TAG, "Pid " + callingPid + " has exceeded half the number of permissible"

                        + "registered listeners. Now at " + numRecordsForPid);

            }



            r = new Record();

            r.binder = binder;

            r.deathRecipient = new TelephonyRegistryDeathRecipient(binder);