Re: [PATCH v4] n_tty: Fix buffer overruns with larger-than-4k pastes

[Peter Hurley]

On 12/16/2013 07:57 PM, Greg Kroah-Hartman wrote:
> On Tue, Dec 10, 2013 at 05:12:02PM -0500, Peter Hurley wrote:
> > readline() inadvertently triggers an error recovery path when
> > pastes larger than 4k overrun the line discipline buffer. The
> > error recovery path discards input when the line discipline buffer
> > is full and operating in canonical mode and no newline has been
> > received. Because readline() changes the termios to non-canonical
> > mode to read the line char-by-char, the line discipline buffer
> > can become full, and then when readline() restores termios back
> > to canonical mode for the caller, the now-full line discipline
> > buffer triggers the error recovery.
> >
> > When changing termios from non-canon to canon mode and the read
> > buffer contains data, simulate an EOF push _without_ the
> > DISABLED_CHAR in the read buffer.
> >
> > Importantly for the readline() problem, the termios can be
> > changed back to non-canonical mode without changes to the read
> > buffer occurring; ie., as if the previous termios change had not
> > happened (as long as no intervening read took place).
> >
> > Preserve existing userspace behavior which allows '\0's already
> > received in non-canon mode to be read as '\0's in canon mode
> > (rather than trigger add'l EOF pushes or an actual EOF).
> >
> > Patch based on original proposal and discussion here
> > https://bugzilla.kernel.org/show_bug.cgi?id=55991
> > by Stas Sergeev <stsp@xxxxxxxxxxxxxxxxxxxxx>
> >
> > Reported-by: Margarita Manterola <margamanterola@xxxxxxxxx>
> > Cc: Maximiliano Curia <maxy@xxxxxxxxxxxxxxxxx>
> > Cc: Pavel Machek <pavel@xxxxxx>
> > Cc: Arkadiusz Miskiewicz <a.miskiewicz@xxxxxxxxx>
> > Acked-by: Stas Sergeev <stsp@xxxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
> > ---
>
> Is this a 3.13-final thing, or can it wait for 3.14-rc1?

Definitely not 3.13 at this point -- it should go to -next.

Regards,
Peter Hurley

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/