[vlc-devel] [PATCH] fix null deref crash

[Lyndon Brown]

On Thu, 2020-09-17 at 22:45 +0300, Rémi Denis-Courmont wrote:
> Le torstaina 17. syyskuuta 2020, 22.34.37 EEST Lyndon Brown a écrit :
> > a few plugins have recently introduced options with no shorttext,
> > resulting in a null dereference crash when their respective entries
> > are
> > selected in the Qt advances prefs tree.
> 
> Passing NULL for a translated string is not defined. The approach in
> your patch 
> is not an adequate solution, because it cannot prevent the NULL
> dereference 
> when NLS is disabled.

Not defined? This concerns the VLC wrappers, not the actual gettext
functions... Also, if it's UB, then there's no issue deviating, if
indeed we are...

With the fix in place, a NULL pointer passed into the wrapper is simply
returned, which is the same as when ENABLE_NLS is not defined.

I've tried the fix, and it works, thus the caller (Qt module code in
this case) is clearly able to handle the NULL perfectly fine when
returned for input to QString::fromUtf8(). I don't see any need to
modify the Qt module (or others if they also cope fine) to handle a
null in any special way.

I'm afraid  don't see why the fix would be inadequate...

> The NULs need to be replaced with valid strings.

Granted, I'll submit the patches to address that. But things should
robustly handle this situation rather than crash.