Date: Fri, 21 Feb 2003 15:26:01 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Yevgeniy Aleynikov <eugenea@infospace.com> Cc: 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: <3E56B589.2E15F3C3@mindspring.com> References: <200302200101.h1K11ZFL056229@beastie.mckusick.com> <3E56A683.5070504@infospace.com>
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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. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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