[Vm-dev] Encoding of path/file names in security plugin

[Nicolas Cellier]

Le jeu. 27 déc. 2018 à 17:40, Alistair Grant <akgrant0710 at gmail.com> a
écrit :

>
> Hi Nicolas,
>
> On Thu, 27 Dec 2018 at 17:05, Nicolas Cellier
> <nicolas.cellier.aka.nice at gmail.com> wrote:
> >
> >
> > Hi all,
> > while reviewing compiler warnings via MSVC for WIN-64 SPUR VM, I saw
> that we incorrectly pass a TCHAR * (via fromSqueak() function) to a
> function (isAccessiblePathName) expecting a WCHAR * (that is UTF-16 encoded
> wide char).
> >
> > TCHAR is a facade, it might be char *, or it might be WCHAR *, depending
> on -DUNICODE compiler flag, or #define UNICODE preprocessor macro.
> >
> > fromSqueak() just copies the image-side ByteString to a null terminated
> string. If -DUNICODE, it copies to a WCHAR *, but this only work for ASCII
> strings.
> >
> > I suggest to rather interpret every path passed to the VM as UTF-8
> encoded, and for that purpose I've committed a change to sqWin32Security.c.
> >
> https://github.com/OpenSmalltalk/opensmalltalk-vm/commit/b52caab76f7f6b91c1f16d9037e0b0a43d968176
>
> I actually thought this was what the VM always did, i.e. paths should
> be UTF-8 encoded in the image before being passed to a plugin.
>
> I agree, but apparently security plugin was left apart from these
evolutions.
It's not a concern for Pharo, this plugin is only for sandboxing, I think
mainly for E-toys.
I think that uptodate technics would be to use some kind of virtualization
like thru Docker.


> > But I see that other platforms flavours (unix at least) require the same
> kind of changes. Any thought before i proceeed?
>
> For Linux and Mac there is:
>
> - ux2sqPath(char *from, int fromLen, char *to, int toLen, int term)
> - sq2uxPath(char *from, int fromLen, char *to, int toLen, int term)
>
> On Mac this takes care of using the Mac specific decomposed UTF-8
> encoding required on that platform.  Both of these assume that the
> image is passing down (and receiving) a UTF-8 encoded string.  See
> platforms/unix/vm/sqUnixCharConv.h.
>
>
> Also, Tobias wrote a helper function for long file names on Windows:
>
>
> https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/476f70605a0352dd7528d251f7403e9233716cdb/platforms/win32/plugins/FilePlugin/sqWin32File.h#L33
>
>
> HTH,
> Alistair
>

Thanks for the reminder, after an interrupt of a year or so, this will
reduce the warm-up time ;)
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