dix: integer overflow in ProcPutImage() [CVE-2014-8092 1/4]

ProcPutImage() calculates a length field from a width, left pad and depth
specified by the client (if the specified format is XYPixmap).

The calculations for the total amount of memory the server needs for the
pixmap can overflow a 32-bit number, causing out-of-bounds memory writes
on 32-bit systems (since the length is stored in a long int variable).

v2: backport to nx-libs 3.6.x (Mike DePaulo)
v3: port to NXdispatch.c rather than dispatch.c (Mike DePaulo)

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>

Conflicts:
	dix/dispatch.c

1 files changed, 3 insertions, 1 deletions

diff --git a/nx-X11/programs/Xserver/hw/nxagent/NXdispatch.c b/nx-X11/programs/Xserver/hw/nxagent/NXdispatch.c
index 3d9ee8c7f..e5bec8aba 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/NXdispatch.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/NXdispatch.c
@@ -2618,7 +2618,9 @@ ProcPutImage(register ClientPtr client)
 
     tmpImage = (char *)&stuff[1];
     lengthProto = length;
-	
+    if (lengthProto >= (INT32_MAX / stuff->height))
+        return BadLength;
+
     if (((((lengthProto * stuff->height) + (unsigned)3) >> 2) + 
 	(sizeof(xPutImageReq) >> 2)) != client->req_len)
 	return BadLength;