xserver/composite
Olivier Fourdan 318085a6f5 composite: initialize border clip even when pixmap alloc fails
If it fails to allocate the pixmap, the function compAllocPixmap() would
return early and leave the borderClip region uninitialized, which may
lead to the use of uninitialized value as reported by valgrind:

 Conditional jump or move depends on uninitialised value(s)
    at 0x4F9B33: compClipNotify (compwindow.c:317)
    by 0x484FC9: miComputeClips (mivaltree.c:476)
    by 0x48559A: miValidateTree (mivaltree.c:679)
    by 0x4F0685: MapWindow (window.c:2693)
    by 0x4A344A: ProcMapWindow (dispatch.c:922)
    by 0x4A25B5: Dispatch (dispatch.c:560)
    by 0x4B082A: dix_main (main.c:282)
    by 0x429233: main (stubmain.c:34)
  Uninitialised value was created by a heap allocation
    at 0x4841866: malloc (vg_replace_malloc.c:446)
    by 0x4F47BC: compRedirectWindow (compalloc.c:171)
    by 0x4FA8AD: compCreateWindow (compwindow.c:592)
    by 0x4EBB89: CreateWindow (window.c:925)
    by 0x4A2E6E: ProcCreateWindow (dispatch.c:768)
    by 0x4A25B5: Dispatch (dispatch.c:560)
    by 0x4B082A: dix_main (main.c:282)
    by 0x429233: main (stubmain.c:34)

 Conditional jump or move depends on uninitialised value(s)
    at 0x48EEDBC: pixman_region_translate (pixman-region.c:2233)
    by 0x4F9255: RegionTranslate (regionstr.h:312)
    by 0x4F9B7E: compClipNotify (compwindow.c:319)
    by 0x484FC9: miComputeClips (mivaltree.c:476)
    by 0x48559A: miValidateTree (mivaltree.c:679)
    by 0x4F0685: MapWindow (window.c:2693)
    by 0x4A344A: ProcMapWindow (dispatch.c:922)
    by 0x4A25B5: Dispatch (dispatch.c:560)
    by 0x4B082A: dix_main (main.c:282)
    by 0x429233: main (stubmain.c:34)
  Uninitialised value was created by a heap allocation
    at 0x4841866: malloc (vg_replace_malloc.c:446)
    by 0x4F47BC: compRedirectWindow (compalloc.c:171)
    by 0x4FA8AD: compCreateWindow (compwindow.c:592)
    by 0x4EBB89: CreateWindow (window.c:925)
    by 0x4A2E6E: ProcCreateWindow (dispatch.c:768)
    by 0x4A25B5: Dispatch (dispatch.c:560)
    by 0x4B082A: dix_main (main.c:282)
    by 0x429233: main (stubmain.c:34)

 Conditional jump or move depends on uninitialised value(s)
    at 0x48EEE33: UnknownInlinedFun (pixman-region.c:2241)
    by 0x48EEE33: pixman_region_translate (pixman-region.c:2225)
    by 0x4F9255: RegionTranslate (regionstr.h:312)
    by 0x4F9B7E: compClipNotify (compwindow.c:319)
    by 0x484FC9: miComputeClips (mivaltree.c:476)
    by 0x48559A: miValidateTree (mivaltree.c:679)
    by 0x4F0685: MapWindow (window.c:2693)
    by 0x4A344A: ProcMapWindow (dispatch.c:922)
    by 0x4A25B5: Dispatch (dispatch.c:560)
    by 0x4B082A: dix_main (main.c:282)
    by 0x429233: main (stubmain.c:34)
  Uninitialised value was created by a heap allocation
    at 0x4841866: malloc (vg_replace_malloc.c:446)
    by 0x4F47BC: compRedirectWindow (compalloc.c:171)
    by 0x4FA8AD: compCreateWindow (compwindow.c:592)
    by 0x4EBB89: CreateWindow (window.c:925)
    by 0x4A2E6E: ProcCreateWindow (dispatch.c:768)
    by 0x4A25B5: Dispatch (dispatch.c:560)
    by 0x4B082A: dix_main (main.c:282)
    by 0x429233: main (stubmain.c:34)

Fix compAllocPixmap() to initialize the border clip even if the creation
of the backing pixmap has failed, to avoid depending later on
uninitialized border clip values.

Related to CVE-2025-26599, ZDI-CAN-25851

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit b07192a8be)

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1831>
2025-02-25 19:38:11 +01:00
..
compalloc.c composite: initialize border clip even when pixmap alloc fails 2025-02-25 19:38:11 +01:00
compext.c Remove "All rights reserved" from Oracle copyright notices 2023-02-25 09:40:41 -08:00
compinit.c composite: Free cs->implicitRedirectExceptions in compCloseScreen 2023-07-18 09:34:39 +00:00
compint.h Remove "All rights reserved" from Oracle copyright notices 2023-02-25 09:40:41 -08:00
compositeext.h composite: move out unexported CompositeIsImplicitRedirectException() 2024-03-03 22:50:07 +00:00
compositeext_priv.h composite: move out unexported CompositeIsImplicitRedirectException() 2024-03-03 22:50:07 +00:00
compoverlay.c Remove "All rights reserved" from Oracle copyright notices 2023-02-25 09:40:41 -08:00
compwindow.c composite: move out unexported CompositeIsImplicitRedirectException() 2024-03-03 22:50:07 +00:00
meson.build Drop Xorg DDX 2024-04-12 10:40:05 +02:00