netdev - Re: [PATCH v1] i40e: Add length check for IFLA_AF

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Date: Mon, 24 Jul 2023 14:21:55 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Leon Romanovsky <leon@...nel.org>, Lin Ma <linma@....edu.cn>
Cc: jesse.brandeburg@...el.com, anthony.l.nguyen@...el.com,
 davem@...emloft.net, edumazet@...gle.com, pabeni@...hat.com,
 richardcochran@...il.com, ast@...nel.org, daniel@...earbox.net,
 hawk@...nel.org, john.fastabend@...il.com,
 intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] i40e: Add length check for IFLA_AF_SPEC parsing

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.

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