From 6ca03b9161d33b1d2b55a3a1a913cf88deb2343f Mon Sep 17 00:00:00 2001
From: Dave Airlie <airlied@gmail.com>
Date: Wed, 10 Apr 2013 06:09:01 +0000
Subject: xf86: fix flush input to work with Linux evdev devices.

So when we VT switch back and attempt to flush the input devices,
we don't succeed because evdev won't return part of an event,
since we were only asking for 4 bytes, we'd only get -EINVAL back.

This could later cause events to be flushed that we shouldn't have
gotten.

This is a fix for CVE-2013-1940.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
---
diff --git a/hw/xfree86/os-support/shared/posix_tty.c b/hw/xfree86/os-support/shared/posix_tty.c
index ab3757a..4d08c1e 100644
--- a/hw/xfree86/os-support/shared/posix_tty.c
+++ b/hw/xfree86/os-support/shared/posix_tty.c
@@ -421,7 +421,8 @@ xf86FlushInput(int fd)
 {
     fd_set fds;
     struct timeval timeout;
-    char c[4];
+    /* this needs to be big enough to flush an evdev event. */
+    char c[256];
 
     DebugF("FlushingSerial\n");
     if (tcflush(fd, TCIFLUSH) == 0)
--
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