linux-kernel - Re: [NFS] [PATCH 008 of 11] knfsd: Prepare knfsd for support of rsize/wsize of up to 1MB, over TCP.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 2 Oct 2006 22:13:04 -0400
From:	"J. Bruce Fields" <bfields@...ldses.org>
To:	Neil Brown <neilb@...e.de>
Cc:	nfs@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	Greg Banks <gnb@...bourne.sgi.com>
Subject: Re: [NFS] [PATCH 008 of 11] knfsd: Prepare knfsd for support of	rsize/wsize of up to 1MB, over TCP.

On Tue, Oct 03, 2006 at 11:36:32AM +1000, Neil Brown wrote:
> The only real problem is that NFSv4 can have arbitrarily large
> non-payload data, and arbitrarily many payloads.  But I guess any
> client that trying to send two full-sized payloads in the one request
> is asking for trouble (I don't suppose the RPC spells this out at
> all?).

The RFC?  Well, it does have a "RESOURCE" error that the server can
return for overly complicated compounds.  It doesn't give much guidance
on when exactly that could happen, but if there's ever a clear case for
returning NFS4ERR_RESOURCE, I think it must be the case of a client
trying to circumvent the maximum read/write size by using multiple read
or write operations in a single compound.

(We have some other odd restrictions on the sorts of compounds we can
accept, which I'd like to relax.  But that's a problem for another day.)

> And the fact that the code change to effect this is so tiny seems to
> imply that most of the code was already assuming that sv_bufsz was
> really the payload size rather than the packet size.

There's also the check at the end of svc_tcp_recvfrom():

	if (svsk->sk_reclen > serv->sv_bufsz) {
		printk(KERN_NOTICE "RPC: bad TCP reclen 0x%08lx (large)\n",
		       (unsigned long) svsk->sk_reclen);
		goto err_delete;
	}

--b.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/