linux-kernel - Re: [RFC 1/2] n_tty: fix dropped output characters

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 14 Apr 2014 15:04:38 +0100
From:	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>
To:	Oliver Neukum <oneukum@...e.de>
Cc:	Johan Hovold <jhovold@...il.com>, Jiri Slaby <jslaby@...e.cz>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
	Peter Hurley <peter@...leysoftware.com>,
	Xiao Jin <jin.xiao@...el.com>, david.a.cohen@...ux.intel.com,
	yanmin.zhang@...el.com
Subject: Re: [RFC 1/2] n_tty: fix dropped output characters

On Mon, 14 Apr 2014 15:05:49 +0200
Oliver Neukum <oneukum@...e.de> wrote:

> On Mon, 2014-04-14 at 13:53 +0100, One Thousand Gnomes wrote:
> > On Fri, 11 Apr 2014 11:41:24 +0200
> > Johan Hovold <jhovold@...il.com> wrote:
> > 
> > > Fix characters being dropped by n_tty_write() due to a failure to
> > > check the return value of tty_put_char() in do_output_char().
> > > 
> > > Characters are currently being dropped by write if a tty driver claims
> > > to have write room available, but still fails to buffer any data
> > 
> > Your driver is buggy. If you advertise a buffer you must honour it and
> > neither shrink nor revoke it.
> 
> Is that a general rule or does it apply only till the next write?

Its a general rule. If you've advertised 5 bytes then you can only
advertise 0 after 5 bytes have been sent your way (or a hangup etc
occurred).

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