netdev - Re: [PATCH] bonding: do not enslave CAN devices

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Date:   Thu, 30 Jan 2020 14:57:39 +0100
From:   Oliver Hartkopp <socketcan@...tkopp.net>
To:     Sabrina Dubroca <sd@...asysnail.net>
Cc:     linux-can@...r.kernel.org, netdev@...r.kernel.org,
        syzbot+c3ea30e1e2485573f953@...kaller.appspotmail.com,
        dvyukov@...gle.com, mkl@...gutronix.de, j.vosburgh@...il.com,
        vfalico@...il.com, andy@...yhouse.net, davem@...emloft.net,
        linux-stable <stable@...r.kernel.org>
Subject: Re: [PATCH] bonding: do not enslave CAN devices

On 30/01/2020 14.41, Sabrina Dubroca wrote:

> 2020-01-30, 14:30:46 +0100, Oliver Hartkopp wrote:
>> Since commit 8df9ffb888c ("can: make use of preallocated can_ml_priv for per
>> device struct can_dev_rcv_lists") the device specific CAN receive filter lists
>> are stored in netdev_priv() and dev->ml_priv points to these filters.
>>
>> In the bug report Syzkaller enslaved a vxcan1 CAN device and accessed the
>> bonding device with a PF_CAN socket which lead to a crash due to an access of
>> an unhandled bond_dev->ml_priv pointer.
>>
>> Deny to enslave CAN devices by the bonding driver as the resulting bond_dev
>> pretends to be a CAN device by copying dev->type without really being one.
> 
> Does the team driver have the same problem?

Good point!

 From a first look into team_setup_by_port() in team.c I would say YES :-)

Thanks for watching out! I would suggest to wait for some more feedback 
and upstream of this fix.

Best regards,
Oliver