From f8c78f83efd202fd5cabc0e7a8013ce07a2bdd27 Mon Sep 17 00:00:00 2001
From: psychon <psychon@726aef4b-f618-498e-8847-2d620e286838>
Date: Wed, 5 Aug 2009 19:35:09 +0000
Subject: [PATCH] Fix a crash bug if c-ares is enabled

CSocket sometimes calls our select() wrapper with writeds == NULL and we didn't
handle this case at all which lead to a NULL pointer dereference.


git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@1586 726aef4b-f618-498e-8847-2d620e286838
---
 Socket.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Socket.cpp b/Socket.cpp
index c771fdb0..7459877b 100644
--- a/Socket.cpp
+++ b/Socket.cpp
@@ -64,6 +64,14 @@ CSockManager::~CSockManager() {
 int CSockManager::Select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
 {
 	int ret;
+	fd_set tmp;
+
+	// Csocket sometimes can use NULL for exceptfds and c-ares doesn't like NULLs
+	if (writefds == NULL)
+	{
+		writefds = &tmp;
+		FD_ZERO(writefds);
+	}
 
 	// We assume that nfds is already the max. number of sockets allowed by
 	// the OS, so we don't need to update it here.