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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Raul Martinez <mraul@qti.qualcomm.com>
Cc: "netfilter@vger.kernel.org" <netfilter@vger.kernel.org>
Subject: Re: Possible nftables U32 equivalent to read packet's data contents
Date: Fri, 1 Sep 2017 12:30:04 +0200	[thread overview]
Message-ID: <20170901103004.GA16773@salvia> (raw)
In-Reply-To: <f337fb23f03b4a60ae45f24a49dd7696@nalasexr02h.na.qualcomm.com>

Hi Raul,

On Wed, Aug 30, 2017 at 09:59:26PM +0000, Raul Martinez wrote:
> Hi all,
> 
> Looking for a way to implement an expression that can read the first
> few bytes of an packet's data contents.  It seems this is only
> possible using raw expressions such as @ll and @nh  with an offset
> that goes past the header length and into the packet's data.  Is
> there another keyword that supports u32 behavior that I am missing?
> Will this approach fail because of some internal check to prevent
> out of bounds reads?
> 
> Another question is if raw expressions have been fixed or is there a
> kernel change required to enable raw expressions?  I still get the
> below error when I try to use 2017 nftables. 

If not much asking, what application layer patterns would you like to
match?

  reply	other threads:[~2017-09-01 10:30 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-30 21:59 Possible nftables U32 equivalent to read packet's data contents Raul Martinez
2017-09-01 10:30 ` Pablo Neira Ayuso [this message]
2017-09-01 16:39   ` Raul Martinez
2017-09-04 20:55     ` Pablo Neira Ayuso
2017-09-05 17:04       ` Raul Martinez
2017-10-03 13:34 ` Pablo Neira Ayuso

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