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List:       kde-devel
Subject:    Re: LD_PRELOAD question
From:       Lubos Lunak <l.lunak () suse ! cz>
Date:       2007-05-25 12:40:36
Message-ID: 200705251440.36279.l.lunak () suse ! cz
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On Thursday 24 of May 2007, Thiago Macieira wrote:
> Lubos Lunak said:
> >  We should probably find a universal solution for this, as this applies
> > to more LD_* stuff (LD_LIBRARY_PATH comes to mind). The wrapper could
> > even restore them itself, the slight problem is that the list of reset
> > vars for setuid apps is hidden somewhere in libc sources and grows over
> > the time. An
> > obvious solution could be dropping the wrapper, but I'd prefer not to -
> > this
> > cluebat actually makes OOM conditions to be handled quite fine :(.
>
> Actually, that's not hard to do...
>
> We need a wrapper for the wrapper. One that dumps the environment to a
> file and then starts the wrapper. The wrapper, in turn, after dropping its
> privileges, resets the environment.
>
> The only thing is that start_kdeinit is meant to be a very small program
> to avoid security issues. But it can be done. Read stdin, change the \n to
> \0 then build a NULL-terminated index of entries. Pass that to execvpe(3).
>
> That resets all of the environment, regardless of the list that libc keeps
> (whichever libc that is, on whichever system).

 That's an excellent idea. Done.

-- 
Lubos Lunak
KDE developer
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SUSE LINUX, s.r.o.   e-mail: l.lunak@suse.cz , l.lunak@kde.org
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