From owner-freebsd-security Sat Dec 1 6:19: 8 2001 Delivered-To: freebsd-security@freebsd.org Received: from pineapple.theshop.net (pineapple.theshop.net [208.128.7.7]) by hub.freebsd.org (Postfix) with ESMTP id 5BCDD37B416 for ; Sat, 1 Dec 2001 06:19:03 -0800 (PST) Received: from bsdprophet.org (cherry46.theshop.net [63.67.33.111]) by pineapple.theshop.net (8.12.0/8.12.0) with ESMTP id fB1EMJw1025605; Sat, 1 Dec 2001 08:22:20 -0600 (CST) Message-ID: <3C08E711.A4B08098@bsdprophet.org> Date: Sat, 01 Dec 2001 08:20:01 -0600 From: scott X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.2.12 i386) X-Accept-Language: en MIME-Version: 1.0 To: Dave Cc: freebsd-security@FreeBSD.ORG Subject: Re: options USER_LDT References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Dave wrote: > > I really have no clue what the kernel option: > options USER_LDT > > means, except this rugged definition I found in LINT (paraphrase): > "Allow applications running in user space to manipulate the Local > Descriptor Table (LDT)" > > Since it didn't come in the GENERIC (FBSD 4.4 REL), I'm assuming that > someone, somewhere, thought it would be a good idea to have this disabled > by default and maybe it was meant to be added in only by people who know > what they are doing. > > Is there a security risk by allowing programs to access the Local > Descriptor Table? (I'm not sure what the LDT is, but if it was off for a > reason I wouldn't want to challenge the decisions of those more informed > than myself. If it wasn't for an efficiency judgement, it could of been > for a security judgement) Yes there is a security risk. Here read all about it: http://www.phrack.org/show.php?p=51&a=9 > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-security" in the body of the message -- Scott To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message