Add a regression test that reproduces the XKB num_levels stack overflow.
The test sends an XkbSetMap request with XkbSetMapResizeTypes that includes
a non-canonical key type with numLevels=255, exceeding XkbMaxShiftLevel
(63). Without the fix, this type would be accepted and stored in the
server's type table. A subsequent ChangeKeyboardMapping would trigger
XkbUpdateKeyTypesFromCore -> XkbKeyTypesForCoreSymbols, where the
oversized num_levels is used as groupsWidth, causing indices into the
tsyms[252] stack buffer to reach up to 1019 and overflow.
Assisted-by: Claude:claude-opus-4-6
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2228>
xclient.send_request() should just take a Request object and handle
to_bytes with the right byte order. This avoids typos/copy-paste errors
in tests when the byte order changes between tests.
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2216>
This test suite is primarily aimed at reproducing the various CVE issues
we've had over the years that require custom crafted protocol requests.
It may also be useful for other testing.
Wrapped in python because pytest is a powerful test suite runner and
writing custom buffers is easy.
The architecture is so that we fork off an X server (one or more of
Xvfb, Xwayland, Xorg) and then run our test clients against that to
check whether we get the right reply, or crash the server, or whether
valgrind complains about something (valgrind is started automatically
for tests that are marked as such).
Tests can be run manually via pytest or via meson test.
Assisted-by: Claude:claude-claude-opus-4-6
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2187>
