Retrieving visuals offered by upstream Xserver is broken in several ways:
a) duplicate elimination breaks out too fast: when a duplicate is found,
it doesn't just skips that one, it completely breaks out the loop,
so subsequent upstream visuals aren't considered anymore. that's leading
to (unpredictable) limit on available color depths (depending on the order
reported by upstream sever)
b) buffer overflow when user specificed different depth/class than default one:
xnestOpenScreen() looks into the wrong table: it's local visuals[] array,
instead of the global (non-dedup'ed) list fetched by xlib. The visuals[]
array is *much* smaller (deduplicated) than the xnestVisuals[] array,
and xnestDefaultVisualIndex is likely to point outside of visual[]'s bounds.
To make it actually work against an Xorg upstream server, the upstream server
needs fix for another bug in the DIX:
https://gitlab.freedesktop.org/xorg/xserver/-/issues/1741https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1644
Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1742
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
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