Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964843AbWBCCAb (ORCPT ); Thu, 2 Feb 2006 21:00:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964845AbWBCCAb (ORCPT ); Thu, 2 Feb 2006 21:00:31 -0500 Received: from clix.aarnet.edu.au ([192.94.63.10]:19356 "EHLO clix.aarnet.edu.au") by vger.kernel.org with ESMTP id S964843AbWBCCAa (ORCPT ); Thu, 2 Feb 2006 21:00:30 -0500 Message-ID: <43E2B8D6.1070707@aarnet.edu.au> Date: Fri, 03 Feb 2006 12:28:46 +1030 From: Glen Turner Organization: Australia's Academic & Research Network User-Agent: Mozilla Thunderbird 1.0.7-1.1.fc4 (X11/20050929) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Alan Cox CC: Kumar Gala , rmk+kernel@arm.linux.org.uk, linux-kernel@vger.kernel.org Subject: Re: 8250 serial console fixes -- issue References: <1138844838.5557.17.camel@localhost.localdomain> In-Reply-To: <1138844838.5557.17.camel@localhost.localdomain> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-MDSA: Yes X-Spam-Score: -104.901 BAYES_00,USER_IN_WHITELIST Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1706 Lines: 48 Hi Alan, The serial console driver has a host of issues - end of line should be CR LF, not LF CR - 'r' option for CTS/RTS flow control assumes CTS is asserted when DSR is not asserted. This is wrong as lots of modems float control lines when off. No control signals are defined is DSR is unasserted. - [SECURITY] 'r' should require DCD to be asserted before outputing characters. Otherwise we talk to Hayes modem command mode. This allows a non-root user to re-program the modem and is a major security issue is people configure calling line identification or encryption to restrict use of the serial console. - 'r' option has insanely slow CTS timeout. So if a terminal server is inactive the kernel can take 30 minutes to boot as each character write to the serial console requires a CTS timeout. All of these have been reported to me multiple times (I'm maintainer of the Remote-Serial-Console-HOWTO). I occassionally clean up and repost a patch I wrote years ago which never gets integrated (although it ships in the patchset of a number of kernels from supercomputer vendors). I'm happy to clean it up again if there's a hope of integration. See for the most recent attempt. Thanks so much, Glen -- Glen Turner Tel: (08) 8303 3936 or +61 8 8303 3936 Australia's Academic & Research Network www.aarnet.edu.au - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/