netdev - Re: [RFC PATCH net-next 03/19] ipv6: Clear nexthop flags upon netdev up

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]

Date:   Wed, 3 Jan 2018 08:32:51 -0700
From:   David Ahern <dsahern@...il.com>
To:     Ido Schimmel <idosch@...sch.org>
Cc:     Ido Schimmel <idosch@...lanox.com>, netdev@...r.kernel.org,
        davem@...emloft.net, roopa@...ulusnetworks.com,
        nicolas.dichtel@...nd.com, mlxsw@...lanox.com
Subject: Re: [RFC PATCH net-next 03/19] ipv6: Clear nexthop flags upon netdev
 up

On 1/3/18 12:44 AM, Ido Schimmel wrote:
>>> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
>>> index ed06b1190f05..b6405568ed7b 100644
>>> --- a/net/ipv6/addrconf.c
>>> +++ b/net/ipv6/addrconf.c
>>> @@ -3484,6 +3484,9 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
>>>  			if (run_pending)
>>>  				addrconf_dad_run(idev);
>>>  
>>> +			/* Device has an address by now */
>>> +			rt6_sync_up(dev, RTNH_F_DEAD);
>>> +
>>
>> Seems like this should be in the NETDEV_UP section, say after
>> addrconf_permanent_addr.
> 
> Unless the `keep_addr_on_down` sysctl is set, then at this stage the
> netdev doesn't have an IP address and we shouldn't clear the dead flag
> just yet.
> 
> This is consistent with IPv4 that clears the dead flag from nexthops in
> a multipath route only if the nexthop device has an IP address. When the
> last IPv4 address is removed from a netdev all the routes using it are
> flushed and there's nothing to clear upon NETDEV_UP.

I have a bug about that IPv4 handling from the FRR team:

$ ip link add dummy1 type dummy
$ ip li set dummy1 up
$ ip route add 1.1.1.0/24 dev dummy1

$ ip addr add dev dummy1 2.2.2.1/24
$ ip ro ls | grep dummy1
1.1.1.0/24 dev dummy1 scope link
2.2.2.0/24 dev dummy1 proto kernel scope link src 2.2.2.1

$ ip addr del dev dummy1 2.2.2.1/24
$ ip ro ls | grep dummy1
<no outpu>

The 1.1.1.0/24 route was removed as well the 2.2.2.0 connected route.