Re: [Qemu-devel] pty/tty functions for BSD too

[Daniel P. Berrange]

On Mon, Aug 18, 2008 at 07:16:36PM +0300, Blue Swirl wrote:
> On 8/18/08, Samuel Thibault <address@hidden> wrote:
> > Anthony Liguori, le Mon 18 Aug 2008 09:06:41 -0500, a écrit :
> >
> > > Samuel Thibault wrote:
> >  > >In Xen, pty/tty functions are enabled for BSD too, shouldn't we enable
> >  > >them in upstream qemu too, as patched below?
> >  > >
> >  >
> >  > And you're sure that these functions compile/work on NetBSD/OpenBSD?
> >
> >
> > The defines are explicit in Xen, so I guess somebody tested it.  I
> >  haven't myself.  I wonder why there is no FreeBSD however.
> 
> The patch does not work on OpenBSD, because while openpty() is
> available, ptsname() isn't.
> 
> I tested the attached version on OpenBSD and Linux, pty name is
> printed correctly.

Passing a non-NULL value to openpty()'s name parameter is not safe

[quote openpty(1)]
BUGS
       Nobody knows how much space should be reserved for name.  So, call-
       ing openpty() or forkpty() with non-NULL name may not be secure.
[/quote]

If BSD has no other way to determine the PTY name, then at least it
should be conditionalized so that systems with ptsname() use it, only
falling back to using the 'name' arg to openpty() for OS lacking ptsname

Regards,
Daniel
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