RE: [nfs-utils] [PATCH 3/3] rpc.mountd: set libtirpc nonblocking mode to avoid DOS

Strösser, Bodo
2014-11-06T19:54:11Z

> -----Original Message-----
> From: NeilBrown [mailto:neilb@suse.de]
> Sent: Wednesday, November 05, 2014 11:35 PM
> To: Strösser, Bodo
> Cc: linux-nfs@vger.kernel.org; bfields@fieldses.org
> Subject: Re: [nfs-utils] [PATCH 3/3] rpc.mountd: set libtirpc nonblocking mode to avoid
> DOS

...

> RPC_MAXDATASIZE is 9000.
> This number is only relevant on the receive size.
> When sending, the "sendsz" passed to svc_tli_create (which default to 64K for
> TCP) is used for the 'record size'.
> When receiving, any 'record' in a tcp connection which is larger than 9000
> bytes will be rejected.
> No message to mountd or statd could ever be that large, so this number
> does not impose a problematic limit.

Thank you for this explanation. That's what I wanted to but didn't know.

Bodo

>
> As far as I can tell, this patch is safe and is a clear improvement.
>
> Reviewed-by: NeilBrown <neilb@suse.de>
>
> Thanks,
> NeilBrown