From: Jonathan Toppins <jtoppins@cumulusnetworks•com>
To: "Rustad, Mark D" <mark.d.rustad@intel•com>,
Alexander Duyck <alexander.duyck@gmail•com>
Cc: "Kirsher, Jeffrey T" <jeffrey.t.kirsher@intel•com>,
"Brandeburg, Jesse" <jesse.brandeburg@intel•com>,
"Nelson, Shannon" <shannon.nelson@intel•com>,
"Wyborny, Carolyn" <carolyn.wyborny@intel•com>,
"Skidmore, Donald C" <donald.c.skidmore@intel•com>,
"Vick, Matthew" <matthew.vick@intel•com>,
"Ronciak, John" <john.ronciak@intel•com>,
"Williams, Mitch A" <mitch.a.williams@intel•com>,
"intel-wired-lan@lists•osuosl.org"
<intel-wired-lan@lists•osuosl.org>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
"gospo@cumulusnetworks•com" <gospo@cumulusnetworks•com>,
"shm@cumulusnetworks•com" <shm@cumulusnetworks•com>,
Alan Liebthal <alanl@cumulusnetworks•com>
Subject: Re: [PATCH v1 net-next 2/2] igb: support SIOCSMIIREG
Date: Fri, 08 May 2015 12:57:48 -0400 [thread overview]
Message-ID: <554CEB0C.40308@cumulusnetworks.com> (raw)
In-Reply-To: <93C443E7-4209-45A3-A54F-949A4ECDD508@intel.com>
On 5/7/15 4:46 PM, Rustad, Mark D wrote:
>> On May 7, 2015, at 10:52 AM, Alexander Duyck <alexander.duyck@gmail•com> wrote:
>>
>>> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
>>> index 720b785..1071a71 100644
>>> --- a/drivers/net/ethernet/intel/igb/igb_main.c
>>> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
>>> @@ -7141,6 +7141,11 @@ static int igb_mii_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
>>> return -EIO;
>>> break;
>>> case SIOCSMIIREG:
>>> + adapter->hw.phy.addr = data->phy_id;
>>> + if (igb_write_phy_reg(&adapter->hw, data->reg_num & 0x1F,
>>> + data->val_in))
>>> + return -EIO;
>>> + break;
>>> default:
>>> return -EOPNOTSUPP;
>>> }
>>
>> How and why is this being used? From what I can tell it looks like it is an easy way to break any of the existing interfaces if it is misused since all you would need to do is specify a phy address that doesn't match the existing PHY in the system and then you would likely lose link, or possibly mess up the configuration on the system requiring.
>>
>> I suspect this is a back door for some piece of user space code that is being given far more permission than it should be.
>
> I don't know about a back door, but the real problem is that it has a
> side-effect of changing the saved value of the phy addr. That is clearly
> a problem and can't be allowed.
This patch was worse before... it had changes in SIOGMIIREG that had
similar side-effects, missed this one.
Checking with some of the platform people here this patch can be
dropped. We don't use it as a backdoor of any kind it was mainly used
for debugging/guess-what-the-phy-addr-was when we originally got the boards.
>
> For the phylib stuff to really work as intended, the igb_write_phy_reg
> really should take the phy address as a parameter instead of getting
> the value from the structure itself. Or a new function should be
> defined that has that interface.
>
> --
> Mark Rustad, Networking Division, Intel Corporation
>
next prev parent reply other threads:[~2015-05-08 16:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-17 20:23 [PATCH v1 net-next 1/2] igb: add PHY support for Broadcom 5461S Jonathan Toppins
2015-04-17 20:24 ` [PATCH v1 net-next 2/2] igb: support SIOCSMIIREG Jonathan Toppins
2015-05-05 17:25 ` Brown, Aaron F
2015-05-05 19:31 ` Jonathan Toppins
2015-05-07 17:52 ` Alexander Duyck
2015-05-07 20:46 ` Rustad, Mark D
2015-05-08 16:57 ` Jonathan Toppins [this message]
2015-04-27 15:44 ` [PATCH v1 net-next 1/2] igb: add PHY support for Broadcom 5461S Jonathan Toppins
2015-05-02 1:45 ` Brown, Aaron F
2015-05-07 16:18 ` Tim Harvey
2015-05-07 16:57 ` Jonathan Toppins
2015-05-07 18:20 ` Alexander Duyck
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