blob: 2034f285c2e716d24a8b8f21968572430a197cfe (
plain) (
tree)
|
|
From 7909f70e73f40113608fba3ddb657c05c3276da1 Mon Sep 17 00:00:00 2001
From: Alan Coopersmith <alan.coopersmith@oracle.com>
Date: Mon, 6 Jan 2014 23:30:14 -0800
Subject: [PATCH 03/31] dix: integer overflow in GetHosts() [CVE-2014-8092 2/4]
GetHosts() iterates over all the hosts it has in memory, and copies
them to a buffer. The buffer length is calculated by iterating over
all the hosts and adding up all of their combined length. There is a
potential integer overflow, if there are lots and lots of hosts (with
a combined length of > ~4 gig). This should be possible by repeatedly
calling ProcChangeHosts() on 64bit machines with enough memory.
This patch caps the list at 1mb, because multi-megabyte hostname
lists for X access control are insane.
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Fedora X Ninjas <x@fedoraproject.org>
---
os/access.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/os/access.c b/os/access.c
index 88a44d9..e7d668a 100644
--- a/os/access.c
+++ b/os/access.c
@@ -1323,6 +1323,10 @@ GetHosts(pointer *data, int *pnHosts, int *pLen, BOOL * pEnabled)
for (host = validhosts; host; host = host->next) {
nHosts++;
n += pad_to_int32(host->len) + sizeof(xHostEntry);
+ /* Could check for INT_MAX, but in reality having more than 1mb of
+ hostnames in the access list is ridiculous */
+ if (n >= 1048576)
+ break;
}
if (n) {
*data = ptr = malloc(n);
@@ -1331,6 +1335,8 @@ GetHosts(pointer *data, int *pnHosts, int *pLen, BOOL * pEnabled)
}
for (host = validhosts; host; host = host->next) {
len = host->len;
+ if ((ptr + sizeof(xHostEntry) + len) > (data + n))
+ break;
((xHostEntry *) ptr)->family = host->family;
((xHostEntry *) ptr)->length = len;
ptr += sizeof(xHostEntry);
--
1.9.3
|
