From 5a4c6621aaf4e886f2c3b633e837ba359fedf921 Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter@cs.unisa.edu.au>
Date: Thu, 10 Apr 2008 08:29:05 +0930
Subject: [PATCH] Xi: some extra checks for validity of kbd and mouse.

Floating SDs are paired with themselves, so the paired device may not be a
proper keyboard or mouse. Put some extra checks in to avoid dereferencing a
nullpointer later.
---
 Xi/exevents.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Xi/exevents.c b/Xi/exevents.c
index f28952fdc..38f6cb57a 100644
--- a/Xi/exevents.c
+++ b/Xi/exevents.c
@@ -730,11 +730,15 @@ ProcessOtherEvent(xEventPtr xE, DeviceIntPtr device, int count)
         {
             kbd = GetPairedDevice(device);
             mouse = device;
+            if (!kbd->key) /* can happen with floating SDs */
+                kbd = NULL;
         }
         else
         {
             mouse = GetPairedDevice(device);
             kbd = device;
+            if (!mouse->valuator || !mouse->button) /* may be float. SDs */
+                mouse = NULL;
         }
         xE->u.keyButtonPointer.state = (kbd) ? (kbd->key->state) : 0;
         xE->u.keyButtonPointer.state |= (mouse) ? (mouse->button->state) : 0;