From owner-freebsd-hackers Fri Feb 21 15:36:17 2003 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5BD5437B405; Fri, 21 Feb 2003 15:36:15 -0800 (PST) Received: from rwcrmhc52.attbi.com (rwcrmhc52.attbi.com [216.148.227.88]) by mx1.FreeBSD.org (Postfix) with ESMTP id B90C843FDD; Fri, 21 Feb 2003 15:36:13 -0800 (PST) (envelope-from julian@elischer.org) Received: from interjet.elischer.org (12-232-168-4.client.attbi.com[12.232.168.4]) by rwcrmhc52.attbi.com (rwcrmhc52) with ESMTP id <20030221233612052001knr2e>; Fri, 21 Feb 2003 23:36:13 +0000 Received: from localhost (localhost.elischer.org [127.0.0.1]) by InterJet.elischer.org (8.9.1a/8.9.1) with ESMTP id PAA53193; Fri, 21 Feb 2003 15:36:10 -0800 (PST) Date: Fri, 21 Feb 2003 15:36:09 -0800 (PST) From: Julian Elischer To: Terry Lambert Cc: Yevgeniy Aleynikov , Kirk McKusick , Matt Dillon , Ian Dowse , peter@FreeBSD.ORG, ache@FreeBSD.ORG, Ken Pizzini , hackers@FreeBSD.ORG, security-officer@FreeBSD.ORG, nectar@FreeBSD.ORG, jedgar@FreeBSD.ORG, rwatson@FreeBSD.ORG, imp@FreeBSD.ORG, security-team@FreeBSD.ORG, wes@FreeBSD.ORG, guido@FreeBSD.ORG Subject: Re: bleh. Re: ufs_rename panic In-Reply-To: <3E56B589.2E15F3C3@mindspring.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Fri, 21 Feb 2003, Terry Lambert wrote: > Yevgeniy Aleynikov wrote: > > As pointed by Ken - we do have alot of file renames (qmail). > > But 2-nd solution, directory-only rename serialization, probably won't > > affect performance as much. > > > > But i believe it's not only us who's gonna have problem when exploit > > code will be known by everybody sooner or later.... > > Dan's non-atomicity assumption on renames is incorrect. > > Even if it's were correct, it's possible to recover fully following > a failure, because metadata updates are ordered (there is a real > synchronization between dependent operations). > > I think that a workaround would be to comment the directory fsync() > code out of qmail, which apparently thinks it's running on extfs > or an async mounted FFS. If you don't want to lose mail then qmail needs to do a fsync after it does the rename. > > -- Terry > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message