1 From 2f605f86acec5ce853f764c41f8c737154a274f5 Mon Sep 17 00:00:00 2001
2 From: Alan Coopersmith <alan.coopersmith@oracle.com>
3 Date: Mon, 6 Jan 2014 23:30:14 -0800
4 Subject: [PATCH 03/33] dix: integer overflow in GetHosts() [CVE-2014-8092
7 GetHosts() iterates over all the hosts it has in memory, and copies
8 them to a buffer. The buffer length is calculated by iterating over
9 all the hosts and adding up all of their combined length. There is a
10 potential integer overflow, if there are lots and lots of hosts (with
11 a combined length of > ~4 gig). This should be possible by repeatedly
12 calling ProcChangeHosts() on 64bit machines with enough memory.
14 This patch caps the list at 1mb, because multi-megabyte hostname
15 lists for X access control are insane.
17 Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
18 Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
19 Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
21 os/access.c | 6 ++++++
22 1 file changed, 6 insertions(+)
24 Index: xorg-server-1.16.0/os/access.c
25 ===================================================================
26 --- xorg-server-1.16.0.orig/os/access.c 2014-12-04 11:11:43.752542885 -0500
27 +++ xorg-server-1.16.0/os/access.c 2014-12-04 11:11:43.748542843 -0500
28 @@ -1323,6 +1323,10 @@
29 for (host = validhosts; host; host = host->next) {
31 n += pad_to_int32(host->len) + sizeof(xHostEntry);
32 + /* Could check for INT_MAX, but in reality having more than 1mb of
33 + hostnames in the access list is ridiculous */
38 *data = ptr = malloc(n);
41 for (host = validhosts; host; host = host->next) {
43 + if ((ptr + sizeof(xHostEntry) + len) > (data + n))
45 ((xHostEntry *) ptr)->family = host->family;
46 ((xHostEntry *) ptr)->length = len;
47 ptr += sizeof(xHostEntry);