Commit graph

2339 commits

Author SHA1 Message Date
Alan Coopersmith
5d84e4779b dix: FindBestPixel: fix implicit fallthrough warning
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 9c9e1afeb2)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:51:08 +02:00
Alan Coopersmith
2d5494ebbb dix: GetPairedDevice: check if GetMaster returned NULL
Clears warning from gcc 14.1:

../dix/devices.c: In function ‘GetPairedDevice’:
../dix/devices.c:2734:15: warning: dereference of NULL ‘dev’
 [CWE-476] [-Wanalyzer-null-dereference]
 2734 |     return dev->spriteInfo? dev->spriteInfo->paired: NULL;
      |            ~~~^~~~~~~~~~~~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit e6fc0861d8)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:51:04 +02:00
Alan Coopersmith
cfda3969a1 dix: HashResourceID: use unsigned integers for bit shifting
Clears warning from gcc 14.1:

../dix/resource.c: In function ‘HashResourceID’:
../dix/resource.c:691:44: warning: left shift of negative value
 [-Wshift-negative-value]
  691 |     return (id ^ (id >> numBits)) & ~((~0) << numBits);
      |                                            ^~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 26a7ab09ea)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:51:00 +02:00
Alan Coopersmith
4335bdeb01 dix: ProcListProperties: skip unneeded work if numProps is 0
No real harm, but clears warning from gcc 14.1:

../dix/property.c: In function ‘ProcListProperties’:
..//dix/property.c:605:27: warning: dereference of NULL ‘temppAtoms’
 [CWE-476] [-Wanalyzer-null-dereference]
  605 |             *temppAtoms++ = pProp->propertyName;
      |             ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 39f337fd49)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:50:57 +02:00
Alan Coopersmith
6d384ab8bf dix: dixChangeWindowProperty: don't call memcpy if malloc failed
It shouldn't matter, since it would have a length of 0, but it
clears warnings from gcc 14.1:

../dix/property.c: In function ‘dixChangeWindowProperty’:
../dix/property.c:287:9: warning: use of possibly-NULL ‘data’ where
 non-null expected [CWE-690] [-Wanalyzer-possible-null-argument]
  287 |         memcpy(data, value, totalSize);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../dix/property.c:324:13: warning: use of possibly-NULL ‘data’ where
 non-null expected [CWE-690] [-Wanalyzer-possible-null-argument]
  324 |             memcpy(data, value, totalSize);
      |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 10cafd0bbe)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:50:53 +02:00
Alan Coopersmith
fc7b6c7549 dix: InitPredictableAccelerationScheme: avoid memory leak on failure
Clears warning from gcc 14.1:

../dix/ptrveloc.c: In function ‘InitPredictableAccelerationScheme’:
../dix/ptrveloc.c:149:9: warning: leak of ‘<unknown>’
 [CWE-401] [-Wanalyzer-malloc-leak]
  149 |         free(vel);
      |         ^~~~~~~~~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 462d13c2f6)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:50:50 +02:00
Alan Coopersmith
83033ce108 dix: CreateScratchGC: avoid dereference of pointer we just set to NULL
Clears warning from gcc 14.1:

../dix/gc.c: In function ‘CreateScratchGC’:
../dix/gc.c:818:28: warning: dereference of NULL ‘pGC’
 [CWE-476] [-Wanalyzer-null-dereference]
  818 |     pGC->graphicsExposures = FALSE;

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 7ee3a52018)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:50:47 +02:00
Alan Coopersmith
44d1b7e4c1 dix: enterleave.c: fix implicit fallthrough warnings
Clears 7 -Wimplicit-fallthrough warnings from gcc 14.1

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 0cb826e3d0)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:50:43 +02:00
Alan Coopersmith
013311852d dix: SetFontPath: don't set errorValue on Success
Clears warning from gcc 14.1:

../dix/dixfonts.c: In function ‘SetFontPath’:
../dix/dixfonts.c:1697:28: warning: use of uninitialized value ‘bad’
 [CWE-457] [-Wanalyzer-use-of-uninitialized-value]
 1697 |         client->errorValue = bad;
      |         ~~~~~~~~~~~~~~~~~~~^~~~~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 1a86fba0d9)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:50:40 +02:00
Alan Coopersmith
2f1ea65b6d dix: PolyText: fully initialize local_closure
Clears warning from gcc 14.1:

../dix/dixfonts.c:1352:15: warning: use of uninitialized value ‘*c.data’
 [CWE-457] [-Wanalyzer-use-of-uninitialized-value]
 1352 |         free(c->data);
      |              ~^~~~~~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit d78836a3a6)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:50:36 +02:00
Alan Coopersmith
0d1b7672e7 dix: check for calloc() failure in Xi event conversion routines
Clears up 12 -Wanalyzer-possible-null-dereference warnings from gcc 14.1

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 25762834c9)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:50:33 +02:00
Peter Hutterer
13cfe2ec85 dix: don't push the XKB state to a non-existing master keyboard
If our master keyboard is disabled, GetMaster() returns NULL and
we segfault in XkbPushLockedStateToSlaves().

Fixes 45fb3a934d
Fixes #1611

(cherry picked from commit 9b983fecf9)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1702>
2024-09-24 10:47:58 +02:00
Alan Coopersmith
ca52da8cba Move sizeof to second argument in calloc calls
Clears -Wcalloc-transposed-args warnings from gcc 14.1, such as:

../dix/main.c:165:42: warning: ‘calloc’ sizes specified with ‘sizeof’ in the
 earlier argument and not in the later argument [-Wcalloc-transposed-args]
  165 |             serverClient = calloc(sizeof(ClientRec), 1);
      |                                          ^~~~~~~~~
../dix/main.c:165:42: note: earlier argument should specify number of
 elements, later size of each element

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
(cherry picked from commit 522f469fe9)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1635>
2024-08-06 10:00:59 +02:00
Michel Dänzer
94228264a7 Drop config directory
Not used anymore on this branch.

(cherry picked from commit 23296633bb)
(cherry picked from commit d07af46a67bc8e68fa050c605bb556bc25886f16)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1483>
2024-04-12 10:40:05 +02:00
Enrico Weigelt, metux IT consult
b335a0fa20 dix: unexport CloseDownClient()
This function isn't used by drivers, so no need to export it.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1383>
2024-03-13 00:47:36 +00:00
Enrico Weigelt, metux IT consult
d84fd3bf19 dix: drop now obsolete cursorScreenDevPriv
Since the two DDX'es which had used this key (xnest and xfree86) now using
their own ones, this global key is obsolete and can be removed.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1342>
2024-03-12 15:24:35 +00:00
Enrico Weigelt, metux IT consult
7f13fc7d2f dix: unexport callback manager init / teardown functions
Those are only needed inside DIX, thus no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1346>
2024-03-12 15:18:17 +00:00
Enrico Weigelt, metux IT consult
738edd3501 dix: unexport eventconvert.h functions
This header isn't installed, so no external modules could use the
functions declared there. Thus we can unexport it all.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1358>
2024-03-11 12:26:44 +01:00
Enrico Weigelt, metux IT consult
2a5e754275 dix: unexport SetAccelerationProfile()
Not used by any module, just locally within one source file, thus
unexport and make it static

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1347>
2024-03-09 18:01:52 +00:00
Enrico Weigelt, metux IT consult
1b983d7e82 dix: unexport FreeVelocityData()
Only used within one source, not used by external modules, thus unexport
and make it static.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1347>
2024-03-09 18:01:52 +00:00
Enrico Weigelt, metux IT consult
9d3766080b dix: unexport BasicComputeAcceleration()
only used locally within one source file, so unexport and make it static.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1347>
2024-03-09 18:01:52 +00:00
Enrico Weigelt, metux IT consult
a09f2540d2 dix: unexport ProcessVelocityData2D()
Only used with on source file, so unexport and make it static.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1347>
2024-03-09 18:01:52 +00:00
Enrico Weigelt, metux IT consult
b598727f1c dix: unexport InitTrackers()
Not used by any modules, thus no need to export it.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1347>
2024-03-09 18:01:52 +00:00
Enrico Weigelt, metux IT consult
4db1f3f760 dix: unexport InitVelocityData()
Not used by any modules, not even outside the source file, thus
no need to export it.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1347>
2024-03-09 18:01:52 +00:00
Enrico Weigelt, metux IT consult
a3ebe4fa41 dix: move non-exported ptrveloc functions to separate header
unclutter ptrveloc.h by moving non-exported declarations into their own
private header file.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1347>
2024-03-09 18:01:52 +00:00
Enrico Weigelt, metux IT consult
040e41c7e9 dix: unexport global variables
Those aren't used by drivers, so no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1375>
2024-03-09 17:23:43 +00:00
Enrico Weigelt, metux IT consult
b1ce5543f1 dix: unexport workqueue functions
These aren't used by drivers, so no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1376>
2024-03-07 22:57:53 +00:00
Enrico Weigelt, metux IT consult
53a0442b87 drop remains of DMX
DMX has long gone, but there's still some fallout from it's removal
yet to be cleaned up.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1362>
2024-03-05 16:57:52 +01:00
Enrico Weigelt, metux IT consult
6999bc49d3 dix: unexport AttachOffloadGPU() and DetachOffloadGPU()
These aren't externally used, thus no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1349>
2024-03-03 23:24:29 +00:00
Enrico Weigelt, metux IT consult
1277bb7143 dix: unexport AttachOutputGPU() and DetachOutputGPU()
These aren't externally used, thus no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1349>
2024-03-03 23:24:28 +00:00
Enrico Weigelt, metux IT consult
71b81a7473 dix: unexport AttachUnboundGPU() and DetachUnboundGPU()
These aren't externally used, thus no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1349>
2024-03-03 23:24:28 +00:00
Enrico Weigelt, metux IT consult
55dc4a8bdc dix: unexport RemoveGPUScreen()
This function isn't used by any modules/drivers, so no need to export it.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1349>
2024-03-03 23:24:28 +00:00
Enrico Weigelt, metux IT consult
27b83c4cd0 dix: unexport AddScreen() and AddGPUScreen()
These aren't used by any drivers/modules, just DDX'es, so no need to export.

Note: tigervnc does use it, but it has it's own DDX, therefore directly
linked in, just like the in-tree DDX'es which doesn't need exporting.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1349>
2024-03-03 23:24:28 +00:00
Enrico Weigelt, metux IT consult
dc84331f5d include: drop obsolete registry.h
Now that there's no actual consumer of it left, it can be dropped.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1348>
2024-03-03 23:20:06 +00:00
Enrico Weigelt, metux IT consult
5f5d55be88 dix: unexport XREGISTRY_UNKNOWN define
It's not used by external modules, thus no need to have it in the
public API.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1348>
2024-03-03 23:20:06 +00:00
Enrico Weigelt, metux IT consult
4ebb02cdda dix: unexport extension registry functions
These aren't used by (known) external modules, thus no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1348>
2024-03-03 23:20:06 +00:00
Enrico Weigelt, metux IT consult
1f5ab6ec28 dix: unexport RegisterResourceName() and LookupResourceName()
These aren't used by external modules, thus no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1348>
2024-03-03 23:20:06 +00:00
Enrico Weigelt, metux IT consult
36e2cf64c8 dix: unexport registry setup/teardown functions
these aren't to be called by modules, thus no need to export them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1348>
2024-03-03 23:20:06 +00:00
Enrico Weigelt, metux IT consult
489485ea7d dix: drop duplicate _X_EXPORT
These are already defined in privates.h

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1274>
2024-03-03 22:34:26 +00:00
Enrico Weigelt, metux IT consult
fe1e2b7b3d dix: unexport and move maxBigRequestSize
* this symbol is a server configuration flag (can be passed via cmdline)
  for limiting the max size of big-requests. there shouldn't be any need
  to use it outside the core X server (in server modules like drivers
  or external extension) - therefore unexport it
* in order to reduce namespace pollution of public (server module API)
  headers, create a new internal header for those tings (more to come)

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1275>
2024-02-23 23:19:32 +00:00
Peter Hutterer
eaa92ea422 Revert "include: move BUG_*() macros to separate header"
This breaks the xf86-input-synaptics driver:

  synaptics.c: In function 'clickpad_guess_clickfingers':
  synaptics.c:2638:5: error: implicit declaration of function 'BUG_RETURN_VAL' [-Werror=implicit-function-declaration]
   2638 |     BUG_RETURN_VAL(hw->num_mt_mask > sizeof(close_point) * 8, 0);

This reverts commit 442aec2219.

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1316>
2024-02-23 23:11:01 +00:00
Enrico Weigelt, metux IT consult
af9f70013a dix: dixutils: make workQueue pointer dix-private
The workQueue pointer is currently declared extern, so that WaitForSomething()
can check wether we've got something in the queue and call ProcessWorkQueue()
then.

But that's trivial to simplify: just let ProcessWorkQueue() return early if
workQueue == NULL. Gives us a better isolation of internal stuff as well as
ProcessWorkQueue() protecting itself from possible segfault.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1310>
2024-02-23 23:06:38 +00:00
Enrico Weigelt
442aec2219 include: move BUG_*() macros to separate header
Yet another step of uncluttering includes: move out the BUG_* macros
into a separate header, which then is included as-needed.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
2024-02-15 23:33:46 +00:00
Enrico Weigelt, metux IT consult
b3b86ae674 replace _X_INLINE by inline in internal static functions
Since xserver is compiled as C99, we just can use the `inline` keyword.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
2024-02-05 19:26:14 +00:00
Wanli Niu
e62246641b dix: Fix segfault if CreateGC() failed in XaceHook()
CreateGC() allocates a new GC and then checks the resource access rights
with XaceHook().

If the call to XaceHook() fails (i.e. GC creation is not granted to the
client), CreateGC() exits early and calls FreeGC() to avoid leaking the
newly allocated GC.

If that happens, the screen's own CreateGC() has not yet been invoked,
and as a result the GC functions (GCfuncs) have not been set yet.

FreeGC() will invoke the funcs->DestroyClip() and the funcs->DestroyGC()
functions, but since those haven't been set, the Xserver will segfault
trying to call a NULL function.

To prevent that issue, make sure the GC's functions are initialized
prior to call them in FreeGC().

Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1625
Reviewed-by: Olivier Fourdan <ofourdan@redhat.com>
2024-02-01 10:10:53 +01:00
Peter Hutterer
133e0d651c dix: fix valuator copy/paste error in the DeviceStateNotify event
Fixes 219c54b8a3
2024-01-22 21:24:58 +00:00
Peter Hutterer
26769aa71f dix: when disabling a master, float disabled slaved devices too
Disabling a master device floats all slave devices but we didn't do this
to already-disabled slave devices. As a result those devices kept their
reference to the master device resulting in access to already freed
memory if the master device was removed before the corresponding slave
device.

And to match this behavior, also forcibly reset that pointer during
CloseDownDevices().

Related to CVE-2024-21886, ZDI-CAN-22840
2024-01-16 09:24:31 +01:00
José Expósito
bc1fdbe465 Xi: do not keep linked list pointer during recursion
The `DisableDevice()` function is called whenever an enabled device
is disabled and it moves the device from the `inputInfo.devices` linked
list to the `inputInfo.off_devices` linked list.

However, its link/unlink operation has an issue during the recursive
call to `DisableDevice()` due to the `prev` pointer pointing to a
removed device.

This issue leads to a length mismatch between the total number of
devices and the number of device in the list, leading to a heap
overflow and, possibly, to local privilege escalation.

Simplify the code that checked whether the device passed to
`DisableDevice()` was in `inputInfo.devices` or not and find the
previous device after the recursion.

CVE-2024-21886, ZDI-CAN-22840

This vulnerability was discovered by:
Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
2024-01-16 09:24:31 +01:00
Peter Hutterer
219c54b8a3 dix: fix DeviceStateNotify event calculation
The previous code only made sense if one considers buttons and keys to
be mutually exclusive on a device. That is not necessarily true, causing
a number of issues.

This function allocates and fills in the number of xEvents we need to
send the device state down the wire.  This is split across multiple
32-byte devices including one deviceStateNotify event and optional
deviceKeyStateNotify, deviceButtonStateNotify and (possibly multiple)
deviceValuator events.

The previous behavior would instead compose a sequence
of [state, buttonstate, state, keystate, valuator...]. This is not
protocol correct, and on top of that made the code extremely convoluted.

Fix this by streamlining: add both button and key into the deviceStateNotify
and then append the key state and button state, followed by the
valuators. Finally, the deviceValuator events contain up to 6 valuators
per event but we only ever sent through 3 at a time. Let's double that
troughput.

CVE-2024-0229, ZDI-CAN-22678

This vulnerability was discovered by:
Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
2024-01-16 09:24:01 +01:00
Peter Hutterer
ece23be888 dix: Allocate sufficient xEvents for our DeviceStateNotify
If a device has both a button class and a key class and numButtons is
zero, we can get an OOB write due to event under-allocation.

This function seems to assume a device has either keys or buttons, not
both. It has two virtually identical code paths, both of which assume
they're applying to the first event in the sequence.

A device with both a key and button class triggered a logic bug - only
one xEvent was allocated but the deviceStateNotify pointer was pushed on
once per type. So effectively this logic code:

   int count = 1;
   if (button && nbuttons > 32) count++;
   if (key && nbuttons > 0) count++;
   if (key && nkeys > 32) count++; // this is basically always true
   // count is at 2 for our keys + zero button device

   ev = alloc(count * sizeof(xEvent));
   FixDeviceStateNotify(ev);
   if (button)
     FixDeviceStateNotify(ev++);
   if (key)
     FixDeviceStateNotify(ev++);   // santa drops into the wrong chimney here

If the device has more than 3 valuators, the OOB is pushed back - we're
off by one so it will happen when the last deviceValuator event is
written instead.

Fix this by allocating the maximum number of events we may allocate.
Note that the current behavior is not protocol-correct anyway, this
patch fixes only the allocation issue.

Note that this issue does not trigger if the device has at least one
button. While the server does not prevent a button class with zero
buttons, it is very unlikely.

CVE-2024-0229, ZDI-CAN-22678

This vulnerability was discovered by:
Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
2024-01-16 09:24:01 +01:00