From 0625342382e712a99a83003e828d8ef19f580bf6 Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gbeutner@serenityos.org>
Date: Sat, 5 Jun 2021 13:03:06 +0200
Subject: [PATCH] Kernel: Return EPIPE when trying to write to an unconnected
 socket

When attempting to write to a socket that is not connected or - for
connection-less protocols - doesn't have a peer address set we should
return EPIPE instead of blocking the thread.
---
 Kernel/Net/IPv4Socket.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Kernel/Net/IPv4Socket.cpp b/Kernel/Net/IPv4Socket.cpp
index 54326ce9a2..260c878e22 100644
--- a/Kernel/Net/IPv4Socket.cpp
+++ b/Kernel/Net/IPv4Socket.cpp
@@ -170,7 +170,7 @@ bool IPv4Socket::can_read(const FileDescription&, size_t) const
 
 bool IPv4Socket::can_write(const FileDescription&, size_t) const
 {
-    return is_connected();
+    return true;
 }
 
 PortAllocationResult IPv4Socket::allocate_local_port_if_needed()
@@ -206,6 +206,9 @@ KResultOr<size_t> IPv4Socket::sendto(FileDescription&, const UserOrKernelBuffer&
         m_peer_port = ntohs(ia.sin_port);
     }
 
+    if (!is_connected() && m_peer_address.is_zero())
+        return EPIPE;
+
     auto routing_decision = route_to(m_peer_address, m_local_address, bound_interface());
     if (routing_decision.is_zero())
         return EHOSTUNREACH;