xserver-multidpi/Xi/xigrabdev.c
Alan Coopersmith 73c63afb93 Xi: unvalidated lengths in Xinput extension [CVE-2014-8095]
Multiple functions in the Xinput extension handling of requests from
clients failed to check that the length of the request sent by the
client was large enough to perform all the required operations and
thus could read or write to memory outside the bounds of the request
buffer.

This commit includes the creation of a new REQUEST_AT_LEAST_EXTRA_SIZE
macro in include/dix.h for the common case of needing to ensure a
request is large enough to include both the request itself and a
minimum amount of extra data following the request header.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
2014-12-08 18:09:48 -08:00

181 lines
5.0 KiB
C

/*
* Copyright © 2009 Red Hat, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Author: Peter Hutterer
*/
/***********************************************************************
*
* Request to grab or ungrab input device.
*
*/
#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif
#include "inputstr.h" /* DeviceIntPtr */
#include "windowstr.h" /* window structure */
#include <X11/extensions/XI2.h>
#include <X11/extensions/XI2proto.h>
#include "exglobals.h" /* BadDevice */
#include "exevents.h"
#include "xigrabdev.h"
#include "inpututils.h"
int
SProcXIGrabDevice(ClientPtr client)
{
REQUEST(xXIGrabDeviceReq);
/*
* Check here for at least the length of the struct we swap, then
* let ProcXIGrabDevice check the full size after we swap mask_len.
*/
REQUEST_AT_LEAST_SIZE(xXIGrabDeviceReq);
swaps(&stuff->length);
swaps(&stuff->deviceid);
swapl(&stuff->grab_window);
swapl(&stuff->cursor);
swapl(&stuff->time);
swaps(&stuff->mask_len);
return ProcXIGrabDevice(client);
}
int
ProcXIGrabDevice(ClientPtr client)
{
DeviceIntPtr dev;
xXIGrabDeviceReply rep;
int ret = Success;
uint8_t status;
GrabMask mask = { 0 };
int mask_len;
unsigned int keyboard_mode;
unsigned int pointer_mode;
REQUEST(xXIGrabDeviceReq);
REQUEST_FIXED_SIZE(xXIGrabDeviceReq, ((size_t) stuff->mask_len) * 4);
ret = dixLookupDevice(&dev, stuff->deviceid, client, DixGrabAccess);
if (ret != Success)
return ret;
if (!IsMaster(dev))
stuff->paired_device_mode = GrabModeAsync;
if (IsKeyboardDevice(dev)) {
keyboard_mode = stuff->grab_mode;
pointer_mode = stuff->paired_device_mode;
}
else {
keyboard_mode = stuff->paired_device_mode;
pointer_mode = stuff->grab_mode;
}
if (XICheckInvalidMaskBits(client, (unsigned char *) &stuff[1],
stuff->mask_len * 4) != Success)
return BadValue;
mask.xi2mask = xi2mask_new();
if (!mask.xi2mask)
return BadAlloc;
mask_len = min(xi2mask_mask_size(mask.xi2mask), stuff->mask_len * 4);
/* FIXME: I think the old code was broken here */
xi2mask_set_one_mask(mask.xi2mask, dev->id, (unsigned char *) &stuff[1],
mask_len);
ret = GrabDevice(client, dev, pointer_mode,
keyboard_mode,
stuff->grab_window,
stuff->owner_events,
stuff->time,
&mask, XI2, stuff->cursor, None /* confineTo */ ,
&status);
xi2mask_free(&mask.xi2mask);
if (ret != Success)
return ret;
rep = (xXIGrabDeviceReply) {
.repType = X_Reply,
.RepType = X_XIGrabDevice,
.sequenceNumber = client->sequence,
.length = 0,
.status = status
};
WriteReplyToClient(client, sizeof(rep), &rep);
return ret;
}
int
SProcXIUngrabDevice(ClientPtr client)
{
REQUEST(xXIUngrabDeviceReq);
REQUEST_SIZE_MATCH(xXIUngrabDeviceReq);
swaps(&stuff->length);
swaps(&stuff->deviceid);
swapl(&stuff->time);
return ProcXIUngrabDevice(client);
}
int
ProcXIUngrabDevice(ClientPtr client)
{
DeviceIntPtr dev;
GrabPtr grab;
int ret = Success;
TimeStamp time;
REQUEST(xXIUngrabDeviceReq);
REQUEST_SIZE_MATCH(xXIUngrabDeviceReq);
ret = dixLookupDevice(&dev, stuff->deviceid, client, DixGetAttrAccess);
if (ret != Success)
return ret;
grab = dev->deviceGrab.grab;
time = ClientTimeToServerTime(stuff->time);
if ((CompareTimeStamps(time, currentTime) != LATER) &&
(CompareTimeStamps(time, dev->deviceGrab.grabTime) != EARLIER) &&
(grab) && SameClient(grab, client) && grab->grabtype == XI2)
(*dev->deviceGrab.DeactivateGrab) (dev);
return Success;
}
void
SRepXIGrabDevice(ClientPtr client, int size, xXIGrabDeviceReply * rep)
{
swaps(&rep->sequenceNumber);
swapl(&rep->length);
WriteToClient(client, size, rep);
}