From b8029948091a04858e0ce649bccca32ff2447207 Mon Sep 17 00:00:00 2001
From: Moxie Marlinspike <moxie@thoughtcrime.org>
Date: Wed, 3 Dec 2014 11:09:01 -0800
Subject: [PATCH] Do a timestamp comparison on unregister events.

// FREEBIE
---
 .../entities/UnregisteredEvent.java            |  7 +++++++
 .../textsecuregcm/push/FeedbackHandler.java    | 18 ++++++++++++++----
 .../textsecuregcm/storage/Device.java          | 17 +++++++++++++++--
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/src/main/java/org/whispersystems/textsecuregcm/entities/UnregisteredEvent.java b/src/main/java/org/whispersystems/textsecuregcm/entities/UnregisteredEvent.java
index af3d3af50..2fdb2f5f8 100644
--- a/src/main/java/org/whispersystems/textsecuregcm/entities/UnregisteredEvent.java
+++ b/src/main/java/org/whispersystems/textsecuregcm/entities/UnregisteredEvent.java
@@ -19,6 +19,9 @@ public class UnregisteredEvent {
   @Min(1)
   private int deviceId;
 
+  @JsonProperty
+  private long timestamp;
+
   public String getRegistrationId() {
     return registrationId;
   }
@@ -30,4 +33,8 @@ public class UnregisteredEvent {
   public int getDeviceId() {
     return deviceId;
   }
+
+  public long getTimestamp() {
+    return timestamp;
+  }
 }
diff --git a/src/main/java/org/whispersystems/textsecuregcm/push/FeedbackHandler.java b/src/main/java/org/whispersystems/textsecuregcm/push/FeedbackHandler.java
index cd1a41d0a..5ebe4801d 100644
--- a/src/main/java/org/whispersystems/textsecuregcm/push/FeedbackHandler.java
+++ b/src/main/java/org/whispersystems/textsecuregcm/push/FeedbackHandler.java
@@ -72,8 +72,13 @@ public class FeedbackHandler implements Managed, Runnable {
       if (device.isPresent()) {
         if (event.getRegistrationId().equals(device.get().getGcmId())) {
           logger.warn("GCM Unregister GCM ID matches!");
-          device.get().setGcmId(null);
-          accountsManager.update(account.get());
+          if (device.get().getPushTimestamp() == 0 ||
+              event.getTimestamp() < device.get().getPushTimestamp())
+          {
+            logger.warn("GCM Unregister Timestamp matches!");
+            device.get().setGcmId(null);
+            accountsManager.update(account.get());
+          }
         }
       }
     }
@@ -90,8 +95,13 @@ public class FeedbackHandler implements Managed, Runnable {
       if (device.isPresent()) {
         if (event.getRegistrationId().equals(device.get().getApnId())) {
           logger.warn("APN Unregister APN ID matches!");
-          device.get().setApnId(null);
-          accountsManager.update(account.get());
+          if (device.get().getPushTimestamp() == 0 ||
+              event.getTimestamp() < device.get().getPushTimestamp())
+          {
+            logger.warn("APN Unregister timestamp matches!");
+            device.get().setApnId(null);
+            accountsManager.update(account.get());
+          }
         }
       }
     }
diff --git a/src/main/java/org/whispersystems/textsecuregcm/storage/Device.java b/src/main/java/org/whispersystems/textsecuregcm/storage/Device.java
index e5f8691c6..c7d81ad8f 100644
--- a/src/main/java/org/whispersystems/textsecuregcm/storage/Device.java
+++ b/src/main/java/org/whispersystems/textsecuregcm/storage/Device.java
@@ -22,8 +22,6 @@ import org.whispersystems.textsecuregcm.auth.AuthenticationCredentials;
 import org.whispersystems.textsecuregcm.entities.SignedPreKey;
 import org.whispersystems.textsecuregcm.util.Util;
 
-import java.io.Serializable;
-
 public class Device {
 
   public static final long MASTER_ID = 1;
@@ -46,6 +44,9 @@ public class Device {
   @JsonProperty
   private String  apnId;
 
+  @JsonProperty
+  private long pushTimestamp;
+
   @JsonProperty
   private boolean fetchesMessages;
 
@@ -79,6 +80,10 @@ public class Device {
 
   public void setApnId(String apnId) {
     this.apnId = apnId;
+
+    if (apnId != null) {
+      this.pushTimestamp = System.currentTimeMillis();
+    }
   }
 
   public String getGcmId() {
@@ -87,6 +92,10 @@ public class Device {
 
   public void setGcmId(String gcmId) {
     this.gcmId = gcmId;
+
+    if (gcmId != null) {
+      this.pushTimestamp = System.currentTimeMillis();
+    }
   }
 
   public long getId() {
@@ -145,4 +154,8 @@ public class Device {
   public void setSignedPreKey(SignedPreKey signedPreKey) {
     this.signedPreKey = signedPreKey;
   }
+
+  public long getPushTimestamp() {
+    return pushTimestamp;
+  }
 }