linux-kernel - Re: [PATCH 04/24] tty: Fix ref counting for port krefs

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:	Thu, 13 Feb 2014 10:36:16 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	Peter Hurley <peter@...leysoftware.com>
Cc:	Marcel Holtmann <marcel@...tmann.org>,
	Gustavo Padovan <gustavo@...ovan.org>,
	Johan Hedberg <johan.hedberg@...il.com>,
	Gianluca Anzolin <gianluca@...tospazio.it>,
	Alexander Holler <holler@...oftware.de>,
	Andrey Vihrov <andrey.vihrov@...il.com>,
	Sander Eikelenboom <linux@...elenboom.it>,
	linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org,
	Jiri Slaby <jslaby@...e.cz>
Subject: Re: [PATCH 04/24] tty: Fix ref counting for port krefs

On Sun, Feb 09, 2014 at 08:59:04PM -0500, Peter Hurley wrote:
> The tty core supports two models for handling tty_port lifetimes;
> the tty_port can use the kref supplied by tty_port (which will
> automatically destruct the tty_port when the ref count drops to
> zero) or it can destruct the tty_port manually.
> 
> For tty drivers that choose to use the port kref to manage the
> tty_port lifetime, it is not possible to safely acquire a port
> reference conditionally. If the last reference is released after
> evaluating the condition but before acquiring the reference, a
> bogus reference will be held while the tty_port destruction
> commences.
> 
> Rather, only acquire a port reference if the ref count is non-zero
> and allow the caller to distinguish if a reference has successfully
> been acquired.
> 
> Cc: Jiri Slaby <jslaby@...e.cz>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Signed-off-by: Peter Hurley <peter@...leysoftware.com>

Acked-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

--
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/