From 5ee29e8a26d7cabba8a12c955bb71a7c60716649 Mon Sep 17 00:00:00 2001
From: Tom <tomut@yahoo.com>
Date: Wed, 16 Sep 2020 14:05:10 -0600
Subject: [PATCH] LibIPC: Check if socket is still open before using socket
 descriptor

Writing to the socket may trigger a close of the socket descriptor
if a disconnect was detected. We need to check if it is still valid
when waiting for a response after attempting to send a synchronous
message.

Fixes #3515
---
 Libraries/LibIPC/Connection.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Libraries/LibIPC/Connection.h b/Libraries/LibIPC/Connection.h
index c02b633489..016669aa3d 100644
--- a/Libraries/LibIPC/Connection.h
+++ b/Libraries/LibIPC/Connection.h
@@ -140,6 +140,8 @@ protected:
                     return m_unprocessed_messages.take(i).template release_nonnull<MessageType>();
             }
 
+            if (!m_socket->is_open())
+                break;
             fd_set rfds;
             FD_ZERO(&rfds);
             FD_SET(m_socket->fd(), &rfds);
@@ -150,14 +152,15 @@ protected:
             ASSERT(rc > 0);
             ASSERT(FD_ISSET(m_socket->fd(), &rfds));
             if (!drain_messages_from_peer())
-                return nullptr;
+                break;
         }
+        return nullptr;
     }
 
     bool drain_messages_from_peer()
     {
         Vector<u8> bytes;
-        for (;;) {
+        while (m_socket->is_open()) {
             u8 buffer[4096];
             ssize_t nread = recv(m_socket->fd(), buffer, sizeof(buffer), MSG_DONTWAIT);
             if (nread < 0) {