From 0c46b770e9be42f0484133861a6b03e843f90556 Mon Sep 17 00:00:00 2001
From: Matthew Chen <charlesmchen@gmail.com>
Date: Wed, 4 Oct 2017 10:19:19 -0400
Subject: [PATCH] Ignore group info requests if sender and recipient aren't
 both known group members.

// FREEBIE
---
 SignalServiceKit/src/Messages/OWSMessageManager.m | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/SignalServiceKit/src/Messages/OWSMessageManager.m b/SignalServiceKit/src/Messages/OWSMessageManager.m
index e30872c97..4b146b86b 100644
--- a/SignalServiceKit/src/Messages/OWSMessageManager.m
+++ b/SignalServiceKit/src/Messages/OWSMessageManager.m
@@ -811,11 +811,21 @@ NS_ASSUME_NONNULL_BEGIN
         return;
     }
 
+    // Ensure sender is in the group.
     if (![gThread.groupModel.groupMemberIds containsObject:envelope.source]) {
         DDLogWarn(@"%@ Ignoring 'Request Group Info' message for non-member of group. %@ not in %@",
             self.tag,
             envelope.source,
             gThread.groupModel.groupMemberIds);
+        return;
+    }
+
+    // Ensure we are in the group.
+    OWSAssert([TSAccountManager isRegistered]);
+    NSString *localNumber = [TSAccountManager localNumber];
+    if (![gThread.groupModel.groupMemberIds containsObject:localNumber]) {
+        DDLogWarn(@"%@ Ignoring 'Request Group Info' message for group we no longer belong to.", self.tag);
+        return;
     }
 
     NSString *updateGroupInfo =