netdev - Re: [PATCH net v2] bonding: Prevent IPv6 link local address on enslaved devices

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 for Android: free password hash cracker in your pocket

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

Date:	Mon, 11 Jan 2016 16:08:48 -0500
From:	Andy Gospodarek <gospo@...ulusnetworks.com>
To:	Karl Heiss <kheiss@...il.com>
Cc:	netdev@...r.kernel.org, Jay Vosburgh <j.vosburgh@...il.com>,
	Veaceslav Falico <vfalico@...il.com>
Subject: Re: [PATCH net v2] bonding: Prevent IPv6 link local address on
 enslaved devices

On Mon, Jan 11, 2016 at 08:28:43AM -0500, Karl Heiss wrote:
> Commit 1f718f0f4f97 ("bonding: populate neighbour's private on enslave")
> undoes the fix provided by commit c2edacf80e15 ("bonding / ipv6: no addrconf
> for slaves separately from master") by effectively setting the slave flag
> after the slave has been opened.  If the slave comes up quickly enough, it
> will go through the IPv6 addrconf before the slave flag has been set and
> will get a link local IPv6 address.
> 
> In order to ensure that addrconf knows to ignore the slave devices on state
> change, set IFF_SLAVE before dev_open() during bonding enslavement.
> 
> Fixes: 1f718f0f4f97 ("bonding: populate neighbour's private on enslave")
> 
> Signed-off-by: Karl Heiss <kheiss@...il.com>

Good find.

Signed-off-by: Andy Gospodarek <gospo@...ulusnetworks.com>

> ---
> - Changes since 'v1':
>   - Revert clearing the IFF_SLAVE flag later during bond release so that
>     RTM_NEWLINK messages will correctly reflect the slave state.
>   - Update commit message for clarity.
> ---
>  drivers/net/bonding/bond_main.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 9e0f8a7..f1692e4 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -1207,7 +1207,6 @@ static int bond_master_upper_dev_link(struct net_device *bond_dev,
>  	err = netdev_master_upper_dev_link_private(slave_dev, bond_dev, slave);
>  	if (err)
>  		return err;
> -	slave_dev->flags |= IFF_SLAVE;
>  	rtmsg_ifinfo(RTM_NEWLINK, slave_dev, IFF_SLAVE, GFP_KERNEL);
>  	return 0;
>  }
> @@ -1465,6 +1464,9 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
>  		}
>  	}
>  
> +	/* set slave flag before open to prevent IPv6 addrconf */
> +	slave_dev->flags |= IFF_SLAVE;
> +
>  	/* open the slave since the application closed it */
>  	res = dev_open(slave_dev);
>  	if (res) {
> @@ -1725,6 +1727,7 @@ err_close:
>  	dev_close(slave_dev);
>  
>  err_restore_mac:
> +	slave_dev->flags &= ~IFF_SLAVE;
>  	if (!bond->params.fail_over_mac ||
>  	    BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
>  		/* XXX TODO - fom follow mode needs to change master's
> -- 
> 1.7.1
>