netdev - Re: [PATCHv2 net] i40e: Implement ndo_gso

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CANr6G5zK3MPYeco6QmfuxUpGR1Qx2PkkCexiTPQRETHnem_-nA@mail.gmail.com>
Date:	Mon, 1 Dec 2014 15:58:45 -0800
From:	Joe Stringer <joestringer@...ira.com>
To:	Jesse Gross <jesse@...ira.com>
Cc:	Tom Herbert <therbert@...gle.com>, netdev <netdev@...r.kernel.org>,
	Shannon Nelson <shannon.nelson@...el.com>,
	"Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
	"linux.nics" <linux.nics@...el.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv2 net] i40e: Implement ndo_gso_check()

On 1 December 2014 at 15:53, Jesse Gross <jesse@...ira.com> wrote:
> On Mon, Dec 1, 2014 at 3:47 PM, Tom Herbert <therbert@...gle.com> wrote:
>> On Mon, Dec 1, 2014 at 3:35 PM, Joe Stringer <joestringer@...ira.com> wrote:
>>> On 21 November 2014 at 09:59, Joe Stringer <joestringer@...ira.com> wrote:
>>>> On 20 November 2014 16:19, Jesse Gross <jesse@...ira.com> wrote:
>>>>> I don't know if we need to have the check at all for IPIP though -
>>>>> after all the driver doesn't expose support for it all (actually it
>>>>> doesn't expose GRE either). This raises kind of an interesting
>>>>> question about the checks though - it's pretty easy to add support to
>>>>> the driver for a new GSO type (and I imagine that people will be
>>>>> adding GRE soon) and forget to update the check.
>>>>
>>>> If the check is more conservative, then testing would show that it's
>>>> not working and lead people to figure out why (and update the check).
>>>
>>> More concretely, one suggestion would be something like following at
>>> the start of each gso_check():
>>>
>>> +       const int supported = SKB_GSO_TCPV4 | SKB_GSO_TCPV6 | SKB_GSO_FCOE |
>>> +                             SKB_GSO_UDP | SKB_GSO_UDP_TUNNEL;
>>> +
>>> +       if (skb_shinfo(skb)->gso_type & ~supported)
>>> +               return false;
>>
>> This should already be handled by net_gso_ok.
>
> My original point wasn't so much that this isn't handled at the moment
> but that it's easy to add a supported GSO type but then forget to
> update this check - i.e. if a driver already supports UDP_TUNNEL and
> adds support for GRE with the same constraints. It seems not entirely
> ideal that this function is acting as a blacklist rather than a
> whitelist.

How much less ideal is it to forget to update the check than to make
this a blacklist?
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html