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SubjectRe: [patch] fix for major securty problem in dquota code
On 12 Mar 1999, Jes Sorensen wrote:

> >>>>> "Andrea" == Andrea Arcangeli <andrea@e-mind.com> writes:
>
> Andrea> My friend Andrea Borgia (master admin of our University)
> Andrea> reported to me this afternoon that dquota could be overridden
> Andrea> by the nfs-server on 2.2.x kernels.
>
> Andrea> I took a look and and the problem was exactly what I
> Andrea> anticipated to you today (since you said me that quota was
> Andrea> fine except when using the nfs-userspace-server, that's the
> Andrea> only bit of code that play with fsuid ;). The problem is that
> Andrea> dquot think that the initiator of the operation is the euid of
> Andrea> nfsd (and nfsd run as root) and not the euid of the student
> Andrea> that is using the NFS client (stored instead in the fsuid
> Andrea> field).
>
> Andrea, if you got your head down in the dquota code (and have an idea
> about what is going on there) you might want to look at the fact that
> it is not SMP safe. I have a report from a guy who had it blow up on
> him like 1-2 times/day when running on SMP, whereas it seems to be
> fine on UP.
>
> Don't take this as a 'you have to fix it' message, only a suggestion
> if you have nothing better to do ;-)

Alan did something in 2.2.2-ac7 that fixed this for us (we got our first
SMP machine that had to use quotas a week or so ago and I put on
2.2.2-ac1...it blew up as soon as I turned on quotas and typed "sync").
Upgrading to ac7 on that machine has fixed/avoided the problem from what I
can see (it's running fine for a few days now :)).

Simon-

| Simon Kirby | Systems Administration |
| mailto:sim@netnation.com | NetNation Communications |
| http://www.netnation.com/ | Tech: (604) 684-6892 |


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