From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pablo Neira Ayuso <pablo@netfilter.org>
Subject: Re: [PATCH net] netfilter: xt_hashlimit: do not allow empty names
Date: Fri, 2 Feb 2018 13:17:23 +0100
Message-ID: <20180202121723.47wr5qosugbdse76@salvia>
References: <1517154099.3715.77.camel@gmail.com>
 <1517162045.3715.78.camel@gmail.com>
 <20180202114938.jxsaun6w3hnfedfz@salvia>
 <20180202115522.bmuukhfib4harcoy@salvia>
 <alpine.LSU.2.20.1802021306530.14157@n3.vanv.qr>
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Cc: Eric Dumazet <eric.dumazet@gmail.com>,
        Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
        Florian Westphal <fw@strlen.de>,
        netfilter-devel@vger.kernel.org, netdev <netdev@vger.kernel.org>
To: Jan Engelhardt <jengelh@inai.de>
Return-path: <netfilter-devel-owner@vger.kernel.org>
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In-Reply-To: <alpine.LSU.2.20.1802021306530.14157@n3.vanv.qr>
Sender: netfilter-devel-owner@vger.kernel.org
List-Id: netdev.vger.kernel.org

On Fri, Feb 02, 2018 at 01:12:08PM +0100, Jan Engelhardt wrote:
> On Friday 2018-02-02 12:55, Pablo Neira Ayuso wrote:
> 
> >On Fri, Feb 02, 2018 at 12:49:38PM +0100, Pablo Neira Ayuso wrote:
> >[...]
> >> bool net_valid_name(const char *name, size_t len)
> >> {
> >>         ...
> >> }
> >
> >Am I missing anything in all these tricky string handling? Thanks!
> 
> One will have to watch out for calls like
> 
> 	net_valid_name(NLA_DATA(some_ifla_name), IFNAMSIZ)
> 
> because quite some nlattrs (IFLA_NAME, IFLA_IFNAME to boot) are NLA_STRINGs
> (rather than NLA_NUL_STRINGs) and they are not \0-terminated.

As long as we use nla_str*() helpers, we're all good.