Date: Fri, 21 Feb 2003 15:36:09 -0800 (PST) From: Julian Elischer <julian@elischer.org> To: Terry Lambert <tlambert2@mindspring.com> Cc: Yevgeniy Aleynikov <eugenea@infospace.com>, Kirk McKusick <mckusick@beastie.mckusick.com>, Matt Dillon <dillon@earth.backplane.com>, Ian Dowse <iedowse@maths.tcd.ie>, peter@FreeBSD.ORG, ache@FreeBSD.ORG, Ken Pizzini <kenp@infospace.com>, 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 Message-ID: <Pine.BSF.4.21.0302211534490.51164-100000@InterJet.elischer.org> In-Reply-To: <3E56B589.2E15F3C3@mindspring.com>
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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
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