The BigRequest extension allows requests larger than the 16-bit length
limit.
It uses integers for the request length and checks for the size not to
exceed the maxBigRequestSize limit, but does so after translating the
length to integer by multiplying the given size in bytes by 4.
In doing so, it might overflow the integer size limit before actually
checking for the overflow, defeating the purpose of the test.
To avoid the issue, make sure to check that the request size does not
overflow the maxBigRequestSize limit prior to any conversion.
The caller Dispatch() function however expects the return value to be in
bytes, so we cannot just return the converted value in case of error, as
that would also overflow the integer size.
To preserve the existing API, we use a negative value for the X11 error
code BadLength as the function only return positive values, 0 or -1 and
update the caller Dispatch() function to take that case into account to
return the error code to the offending client.
CVE-2025-49176
This issue was discovered by Nils Emmerich <nemmerich@ernw.de> and
reported by Julian Suleder via ERNW Vulnerability Disclosure.
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/2024>
This callback only had been added for Xwayland, which is gone now,
so we don't need it anymore. For property filtering (eg. security
extensions), we have PropertyFilterCallback.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
It always had it's own lifecycle (not been part of Xorg releases),
doesn't make sense to maintain a competing implementation that we
won't use anyways.
Once that's gone, we can also drop few things in core/dix that had
been added just for xwayland only.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
in struct _Screen (include/scrnintstr.h) there is a PRIVATE_LAST-sized array,
having another private increases PRIVATE_LAST, the array increases in size,
moving everything below it down. this breaks ABI for nvidia driver
Signed-off-by: dasha_uwu <dasha@linuxping.win>
Nvidia has a strange habit of messing with really internal stuff,
so need to add it to the executable's symbol table.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
As long as the wfb module is still a separate shared object, this
function needs to be in the symbol table.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Adding data structure and initial data for namespace configuration.
Built-in namespaces are ROOT and ANONYMOUS.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
This helper checks whether a given XID belongs to some screen's
root window. It does so by looking up the window and comparing that
with the window's screen's root window pointer. The resource lookup
is intentionally being on behalf of the serverClient, so the fired
XACE hook doesn't treat it as an actual client's request.
It's explicitly designed for being used by callback handlers.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Add a little helper that's looking up the ClientPtr to the client
of the owner of given XID. The lookup is solely done on the ID space,
the actual resource doesn't even need to exist.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Add hooks for filtering and fully rewrite rewrite selection requests
and events (what existing XACE hooks cannot do), e.g. for supporting
separate selection name spaces.
The hook can change individual fields in the parameter struct, so
operation continues with these changed values (eg. replace the original
selection name atom by a different one). It's also possible to stop
operations completely (with given result code) - in that case the
hook needs to take care of the remaining work to do (eg. sending events)
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
This hook allows extensions to intercept client requests for changing
window attributes. It can either change the parameters or skip the
entire call (eg. handle all itself) so just the hook provided result
code is returned to the client.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
a) no need to checking for win->optional == NULL before calling
MakeWindowOptional(), because it checks itself
(except some cases where it's presence has it's own semantics,
or prevent unnecessary allocations)
b) lots of call sites didn't check for allocation failure.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Allow extensions to catch in right after a screen's root window has
been finally initialized
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Not used by any drivers, and shouldn't be used by them.
Needs to _X_EXPORT'ed, as long as glx is a separate module.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Lots of logging functions, especially init and teardown aren't called
by any drivers/modules, so no need to keep them exported.
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>
Instead of highjacking core request handlers, use the recently introduced
DDX/driver API.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
We don't have a standard protocol for enabling VRR yet, but some time ago an
ad-hoc had been made in the amdgpu driver (later also copied to modsetting),
which works by client setting the _VARIABLE_REFRESH window property.
The way it's currently done - driver is highjacking the X_ChangeProperty and
X_DeleteProperty request handlers - is pretty fragile, and is also a violation
of layers: drivers never should be twisted with core protocol details. (And in
the future, this should be done by some suitable extension).
Another problem is Xinerama: when it's enabled, this only works on the first
screen - the others won't ever see this signal, no matter on which one(s) the
Window is physically placed (for the wire protocol, all windows are on screen 0,
unless the client explicitly creates them on another one)
This commit adds a generic Screen proc for telling the DDX, whether the VRR mode
shall be changed (for now, it's only DISABLED and ENABLED). Drivers can hook into
here in order to receive this signal, w/o having to highjack any core request
handlers. Catching the property change is now entirely done in the DIX.
The (non-standard) status qou of (ab)using window properties is kept, but it's
now also easy to add a new signaling mechanism, in case a standard is agreed on.
Yet a quite naive implementation (eg. not acting on moving windows between screens),
but enough to fix the most pressing problems supporting extra screens in general,
as well as stopping the highjacking of core request handlers by drivers.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
XServer refuses the create windows with different color depth than the parent's,
just in the special case that neither border pixmap nor border pixel is given,
even if the screen supports it. (that's also one of the reasons why Xnest fails
to run with different color depths than the default one)
it really doesn't make sense to deny this, while it's allowed when having a
border color or pixmap set.
Fixes: ded6147b - R6.6 is the Xorg base-line
Closes:https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1644
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Only key difference that calloc(), in contrast to rellocarray(),
is zero-initializing. The overhead is hard to measure on today's
machines, and it's safer programming practise to always allocate
zero-initialized, so one can't forget to do it explicitly.
Cocci rule:
@@
expression COUNT;
expression LEN;
@@
- xallocarray(COUNT,LEN)
+ calloc(COUNT,LEN)
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>
It's only ever used inside dix/grabs.c, no outside users,
no no need to keep it public.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
We're clearing the whole object size anyways, so we can directly
use calloc() instead of malloc() plus memset().
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>
Several places outside Xi (eg. dix, security hooks, ...) need to know the
actual XI base opcode. This formerly had been done by a global variable,
which is filled on XI init. This has some drawbacks, eg. requires that
XI really is initialized before anybody else attempting to access this
variable - changes in extension init order could be dangerous.
Since extension opcodes are now (compile-time) fixed for all known
extensions (including XI), this isn't needed anymore. We can really
rely on the XI extension always having the same opcode base. So we
can drop that variable entirely and use the corresponding define instead.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Assign fixed opcodes for known (in-tree) extensions and add
defines for them. Other places (eg. security extensions) that
need to know those opcodes now can directly use those defines
not having to look them up at runtime.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
In order to allow extensions being registered at fixed opcodes,
there need to be a reserved slot range. Thus `NumExtensions` needs
to start out with the upper ceiling of the reserved slot space.
Thus it cannot tell whether the array already had been allocated,
and some slots now may be NULL, so we need some extra checks.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
The function returns X result codes, but -1 isn't a valid value here.
Therefore all callers explicitly translate -1 to BadValue, so we can return
that directly instead of -1.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
No need for using a complex callback machinery, if we just move the
little pieces of byte-swapping directly into the request handler.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
No need for using a complex callback machinery, if we just move the
little pieces of byte-swapping directly into the request handler.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Olivier Fourdan
Enrico Weigelt, metux IT consult
dasha_uwu