In Xinerama/Panoramix configuration there's one screen that's having special
meaning - it's used for simulating as the frontend for all client operations:
the clients (should) only talk to that screen, while panoramix subsystem is
proxying those operations to all the other screens (with certain changed
applied, eg. coordinate transformations).
Historically, this screen happens to be the first one in the system (some of
it's proc's are hooked up in order to achieve desired behaviour). That's why it
used to be accessed via screenInfo.screens[0] - that already had been encapsulated
into a tiny helper `dixGetFirstScreen()`.
a) the correct terminus technicus for a situation where one device (or SW entity)
entirely controlling others is a master-slave-relationship: the controlling
device/entity is `master`, the controlled ones are `slave` (to that specific
master).
b) the term "first screen" is inacurate and misleading here: what the caller's are
actually interest in isn't the first entry in the screen array, but the screen
that's controlling the others. With upcoming refactoring of the Xinerama/Panoramix
subsystem, this might well be a different array index than 0.
c) the term `default` also wouldn't match: `default` implies there's a real practical
choice, and such value applies when no explicit choice has been made. But in this
case, it practically doesn't make sense (except perhaps for debugging purpose)
for a client to use any different screen.
Therefore fixing the function name to the correct technical terminology.
(for sake of patch readability, renaming corresponding variables is left to
subsequent patches).
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Instead of everybody directly accessing the (internal) screenInfo struct,
let those consumers only interested in first screen use a little helper.
Also caching the value if it's needed several times.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Move the walking loops on Xinerama screens into lambda-esque macros:
the callers look quite like we've been using lambda functions and
closures, but actually are just fancy macro trickery.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
When iterating screen lists, consistently use the same variable name
`walkScreenIdx` for holding current screen index everywhere.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Since we're already statically initializing the reply header anyways,
use the default case values here and overwrite them only when requested
version is lower than server's one.
That code path is so cold (at max only called once per client), we really
don't need to care whether there's any chance for saving a few cycles.
So not trying to be clever, but instead focus on readability.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
When iterating screen lists, consistently use the same variable name
`walkScreen` for holding current screen pointer everywhere.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Since most of the extension init logic (and on/off switches for them)
is driven from miext, this seems the appropriate place for the header.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
The dispatcher functions are much more complex than they're usually are
(just switch/case statement). Bring them in line with the standard scheme
used in the Xserver, so further steps become easier.
It's also much cleaner to use the defines from proto headers instead of
raw numbers.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
The current way of switching between Xinerama and single-screen handlers
is quite complicated and needs call vector tables that are changed on
the fly, which in turn makes dispatching more complicated.
Reworking this into a simple and straight code flow, where individual request
procs just look at a flag to decide whether to call the Xinerama or single
screen version.
This isn't just much easier to understand (and debug), but also removes the need
or the call vectors, thus allowing further simplification of the dispatcher.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
* use their actual path instead of relying this to be in compiler's
include path list.
* no need to do it only conditionally, no #ifdef needed
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
All relevant things are now in dix/colormap_priv.h, so no need
to include colormapst.h anymore.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
a) an internal function that's not used by any drivers
b) conflicting with function/define of same name on win32
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Retrieves the ClientPtr for the owner of given resource.
This way reducing the sites directly accessing clients[] array.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Make it type-safe and a bit more obvious what it really does,
also adding some inline documentation. Since it's just some
bit shifting magic, it's qualified for inlining.
The CLIENT_ID() macro isn't used by any external modules, so the
new function doesn't need to be in a public header.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Hide internals (drop the need to include windowstr.h), make it typesafe
as well as the naming easier to understand.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Using calloc() instead of malloc() as preventive measure, so there
never can be any hidden bugs or leaks due uninitialized memory.
The extra cost of using this compiler intrinsic should be practically
impossible to measure - in many cases a good compiler can even deduce
if certain areas really don't need to be zero'd (because they're written
to right after allocation) and create more efficient machine code.
The code pathes in question are pretty cold anyways, so it's probably
not worth even thinking about potential extra runtime costs.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Wrapping ScreenRec's function pointers is problematic for many reasons,
so use the new screen close notify hook instead.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Wrapping ScreenRec's function pointers is problematic for many reasons,
so use the new window position notify hook instead.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Wrapping ScreenRec's function pointers is problematic for many reasons,
so use the new window position notify hook instead.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Wrapping ScreenRec's function pointers is problematic for many reasons,
so use the new window destructor hook instead.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Unlikely to practically happen, but still safer to just check for sure.
A simple zero-value test doesn't cost us much (on modern CPUs perhaps
not even a full clock cycle).
| ../composite/compalloc.c: In function ‘compRedirectWindow’:
| ../composite/compalloc.c:167:35: warning: dereference of NULL ‘pClient’ [CWE-476] [-Wanalyzer-null-dereference]
| 167 | ccw->id = FakeClientID(pClient->index);
| | ~~~~~~~^~~~~~~
| ../composite/compalloc.c: In function ‘compUnredirectWindow’:
| ../composite/compalloc.c:331:75: warning: dereference of NULL ‘pClient’ [CWE-476] [-Wanalyzer-null-dereference]
| 331 | if (ccw->update == update && dixClientIdForXID(ccw->id) == pClient->index) {
| | ~~~~~~~^~~~~~~
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
FOR_NSCREENS() is just alias for FOR_NSCREENS_BACKWARD(). In many cases
it really matters that we're going backwards and the last iteration visited
the screen #0, and that one is panoramix-wrapped.
Thus directly calling FOR_NSCREENS_BACKWARD() here and dropping the alias.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
The include has become empty now. Not used by any external drivers,
so it can be dropped now.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
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>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1828>
The function compCheckRedirect() may fail if it cannot allocate the
backing pixmap.
In that case, compRedirectWindow() will return a BadAlloc error.
However that failure code path will shortcut the validation of the
window tree marked just before, which leaves the validate data partly
initialized.
That causes a use of uninitialized pointer later.
The fix is to not shortcut the call to compHandleMarkedWindows() even in
the case of compCheckRedirect() returning an error.
CVE-2025-26599, ZDI-CAN-25851
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>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1828>
PANORAMIX was the original working title of the extension, before it became
official standard. Just nobody cared about fixing the symbols to the official
naming.
For backwards compatibility with drivers, the old PANORAMIX symbol will
still be set.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1258>
The symbol controls whether to include dix-config.h, and it's always set,
thus we don't need it (and dozens of ifdef's) anymore.
This commit only removes them from our own source files, where we can
guarantee that dix-config.h is present - leaving the (potentially exported)
headers untouched.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
We alread have several of these calls, that aren't interested in result value,
explicitly casting to void. Fixing this up for the remaining ones.
This is helpful for the human reader as well as quality analysis tools.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1648>
