xserver/xkb
Olivier Fourdan 475d9f49ac xkb: Prevent overflow in XkbSetCompatMap()
The XkbCompatMap structure stores its "num_si" and "size_si" fields
using an unsigned short.

However, the function _XkbSetCompatMap() will store the sum of the
input data "firstSI" and "nSI" in both XkbCompatMap's "num_si" and
"size_si" without first checking if the sum overflows the maximum
unsigned short value, leading to a possible overflow.

To avoid the issue, check whether the sum does not exceed the maximum
unsigned short value, or return a "BadValue" error otherwise.

CVE-2025-62231, ZDI-CAN-27560

This vulnerability was discovered by:
Jan-Niklas Sohn working with Trend Micro Zero Day Initiative

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2086>
2025-10-28 13:22:43 +01:00
..
ddxBeep.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
ddxCtrls.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
ddxKillSrv.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
ddxLEDs.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
ddxLoad.c Revert "xkb: unexport functions from xkbfmisc.c" 2025-07-12 11:47:06 -07:00
ddxPrivate.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
ddxVT.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
maprules.c Revert "xkb: drop unused XkbRF_LoadRulesByName()" 2025-07-12 11:47:06 -07:00
meson.build Add a Meson build system alongside autotools. 2017-04-26 15:25:27 -07:00
README.compiled Strip trailing whitespace from source files 2025-10-05 11:56:48 -07:00
xkb-procs.h xkb: rename xkb.h to xkb-procs.h 2022-07-08 14:27:04 +00:00
xkb.c xkb: Prevent overflow in XkbSetCompatMap() 2025-10-28 13:22:43 +01:00
xkbAccessX.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
xkbActions.c Revert "dix: unexport GetSpritePosition()" 2025-09-06 17:01:37 +00:00
XKBAlloc.c xkb: ensure XkbAllocNames sets num_rg to 0 on allocation failure 2025-02-26 13:15:34 +00:00
xkbDflts.h Use ARRAY_SIZE all over the tree 2017-10-30 13:45:20 -04:00
xkbEvents.c xkb: Free the XKB resource when freeing XkbInterest 2025-10-28 13:22:43 +01:00
xkbfmisc.c Revert "xkb: move XkbConvertGetByNameComponents and make it static" 2025-07-12 11:47:06 -07:00
XKBGAlloc.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
xkbgeom.h Drop trailing whitespaces 2014-11-12 10:25:00 +10:00
xkbInit.c Revert "include: drop now empty xkbfile.h" 2025-07-12 11:47:06 -07:00
xkbLEDs.c drop obsolete HAVE_DIX_CONFIG_H 2024-10-10 13:38:31 +00:00
XKBMAlloc.c xkb: Check that needed is > 0 in XkbResizeKeyActions 2025-02-26 13:15:34 +00:00
XKBMisc.c Revert "xkb: unexport functions from xkbfmisc.c" 2025-07-12 11:47:06 -07:00
xkbout.c Revert "xkb: unexport functions from xkbfmisc.c" 2025-07-12 11:47:06 -07:00
xkbPrKeyEv.c xwayland: Don't run key behaviors and actions 2025-02-03 05:37:48 +00:00
xkbsrv_priv.h xkb: Make the RT_XKBCLIENT resource private 2025-10-28 13:22:43 +01:00
xkbSwap.c xkb: drop swapping request length fields 2025-02-06 22:28:48 +00:00
xkbtext.c xkb: Add tbGetBufferString helper function 2025-02-26 13:15:34 +00:00
xkbtext_priv.h xkbtext_priv.h: fix typo in header guard definition 2024-11-10 12:51:10 -08:00
xkbUtils.c xkb: Always use MAP_LENGTH keymap size 2025-01-13 11:44:11 +01:00
XKM_file_format.txt Fix spelling/wording issues 2020-07-05 13:07:33 -07:00
xkmread.c Revert "xkb: unexport functions from xkbfmisc.c" 2025-07-12 11:47:06 -07:00

The X server uses this directory to store the compiled version of the
current keymap and/or any scratch keymaps used by clients.  The X server
or some other tool might destroy or replace the files in this directory,
so it is not a safe place to store compiled keymaps for long periods of
time.  The default keymap for any server is usually stored in:
     X<num>-default.xkm
where <num> is the display number of the server in question, which makes
it possible for several servers *on the same host* to share the same
directory.

Unless the X server is modified, sharing this directory between servers on
different hosts could cause problems.