Re: [groff] 01/01: preconv: Support Emacs coding tags at file ends.

[Ralph Corderoy]

Hi Ingo,

> but are we really sure that that nobody relies on the possibility to
> run their own preprocessor before preconv(1)?

They of course do.

> And that nobody pipes input into groff(1) on stdin?

All the time.

> This is a more serious bug, a potential security vulnerability:
> Use after free.

And I can see a probable wandering off the end of the buffer too.

> I'd suggest that we first decide whether we want to encourage people
> to put the coding at the end even though that clearly reduces
> robustness and possibly harms portability.

It's a bad idea.  The clue is:

> > +// Get coding tag from Emacs local variables list at end of file.

A non-Unix text editor which liked to do things its way, e.g. the
three-byte ‘foo’ is a text file.  Putting how to read a file at the end
of that file is such a daft idea when placed in a Unix context; it's
alien and should not be encouraged.

-- 
Cheers, Ralph.