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Subject: Re: Insanely high baud rates
To:     Craig Milo Rogers <rogers@isi.edu>,
        Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc:     linux-serial@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>, Johan Hovold <johan@kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>
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From:   "H. Peter Anvin" <hpa@zytor.com>
Message-ID: <aa19265c-f39a-cb7d-1215-1c663d15ac30@zytor.com>
Date:   Thu, 11 Oct 2018 12:39:21 -0700
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On 10/11/18 12:36 PM, Craig Milo Rogers wrote:
> On 18.10.11, Alan Cox wrote:
>> I mean - what is the baud rate of a pty  ?
> 
> 	Solaris made the distinction between B0, which means pty hangup mode,
> and any other baud rate:
> 
> https://docs.oracle.com/cd/E88353_01/html/E37851/pty-4d.html
> 
> 	But... why not implement a pty bandwidth limitation layer?  You say, I
> need to justify it?  It's for, uh... protecting the system from unrestricted
> pty usage DOS attacks!  Yeah.  That's what it's for.

B0 is hangup, that's not in question.

	-hpa