mirror of
https://gitlab.freedesktop.org/xorg/xserver.git
synced 2026-06-08 22:08:25 +02:00
5328a544ba
As reported by valgrind:
== Conditional jump or move depends on uninitialised value(s)
== at 0x547E5B: CheckModifierMap (xkb.c:1972)
== by 0x54A086: _XkbSetMapChecks (xkb.c:2574)
== by 0x54A845: ProcXkbSetMap (xkb.c:2741)
== by 0x556EF4: ProcXkbDispatch (xkb.c:7048)
== by 0x454A8C: Dispatch (dispatch.c:553)
== by 0x462CEB: dix_main (main.c:274)
== by 0x405EA7: main (stubmain.c:34)
== Uninitialised value was created by a heap allocation
== at 0x4840B26: malloc (vg_replace_malloc.c:447)
== by 0x592D5A: AllocateInputBuffer (io.c:981)
== by 0x591F77: InsertFakeRequest (io.c:516)
== by 0x45CA27: NextAvailableClient (dispatch.c:3629)
== by 0x58FA81: AllocNewConnection (connection.c:628)
== by 0x58FC70: EstablishNewConnections (connection.c:692)
== by 0x58FFAA: HandleNotifyFd (connection.c:809)
== by 0x593F42: ospoll_wait (ospoll.c:660)
== by 0x58B9B6: WaitForSomething (WaitFor.c:208)
== by 0x4548AC: Dispatch (dispatch.c:493)
== by 0x462CEB: dix_main (main.c:274)
== by 0x405EA7: main (stubmain.c:34)
The issue is that the loop in CheckModifierMap() reads from wire without
verifying that the data is within the request bounds.
The req->totalModMapKeys value could exceed the actual data provided,
causing reads of uninitialized memory.
To fix that issue, we add a bounds check using _XkbCheckRequestBounds,
but for that, we need to also pass a ClientPtr parameter, which is not
a problem since CheckModifierMap() is a private, static function.
CVE-2026-34002, ZDI-CAN-28737
This vulnerability was discovered by:
Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit
|
||
|---|---|---|
| .. | ||
| ddxBeep.c | ||
| ddxCtrls.c | ||
| ddxKillSrv.c | ||
| ddxLEDs.c | ||
| ddxLoad.c | ||
| ddxPrivate.c | ||
| ddxVT.c | ||
| Makefile.am | ||
| maprules.c | ||
| meson.build | ||
| README.compiled | ||
| xkb.c | ||
| xkb.h | ||
| xkbAccessX.c | ||
| xkbActions.c | ||
| XKBAlloc.c | ||
| xkbDflts.h | ||
| xkbEvents.c | ||
| xkbfmisc.c | ||
| XKBGAlloc.c | ||
| xkbgeom.h | ||
| xkbInit.c | ||
| xkbLEDs.c | ||
| XKBMAlloc.c | ||
| XKBMisc.c | ||
| xkbout.c | ||
| xkbPrKeyEv.c | ||
| xkbSwap.c | ||
| xkbtext.c | ||
| xkbUtils.c | ||
| XKM_file_format.txt | ||
| xkmread.c | ||
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.