Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 25 Jul 2023 08:40:46 +0300
From:   Leon Romanovsky <leon@kernel.org>
To:     Jakub Kicinski <kuba@kernel.org>
Cc:     Lin Ma <linma@zju.edu.cn>, jesse.brandeburg@intel.com,
        anthony.l.nguyen@intel.com, davem@davemloft.net,
        edumazet@google.com, pabeni@redhat.com, richardcochran@gmail.com,
        ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org,
        john.fastabend@gmail.com, intel-wired-lan@lists.osuosl.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] i40e: Add length check for IFLA_AF_SPEC parsing
Message-ID: <20230725054046.GK11388@unreal>
References: <20230723075042.3709043-1-linma@zju.edu.cn>
 <20230724174435.GA11388@unreal>
 <20230724142155.13c83625@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230724142155.13c83625@kernel.org>
Precedence: bulk

On Mon, Jul 24, 2023 at 02:21:55PM -0700, Jakub Kicinski wrote:
> On Mon, 24 Jul 2023 20:44:35 +0300 Leon Romanovsky wrote:
> > > @@ -13186,6 +13186,9 @@ static int i40e_ndo_bridge_setlink(struct net_device *dev,
> > >  		if (nla_type(attr) != IFLA_BRIDGE_MODE)
> > >  			continue;
> > >  
> > > +		if (nla_len(attr) < sizeof(mode))
> > > +			return -EINVAL;
> > > +  
> > 
> > I see that you added this hunk to all users of nla_for_each_nested(), it
> > will be great to make that iterator to skip such empty attributes.
> > 
> > However, i don't know nettlink good enough to say if your change is
> > valid in first place.
> 
> Empty attributes are valid, we can't do that.

Maybe Lin can add special version of nla_for_each_nested() which will
skip these empty NLAs, for code which don't allow empty attributes.

> 
> But there's a loop in rtnl_bridge_setlink() which checks the attributes.
> We can add the check there instead of all users, as Leon points out.
> (Please just double check that all ndo_bridge_setlink implementation
> expect this value to be a u16, they should/)
> -- 
> pw-bot: cr