From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: Denis Kenzior <denkenz@gmail.com>, iwd@lists.linux.dev
Subject: Re: Wrong source MAC for DHCP requests with AddressRandomization=network
Date: Fri, 24 Nov 2023 17:53:03 +0100 [thread overview]
Message-ID: <87plzzhz4g.fsf@toke.dk> (raw)
In-Reply-To: <0d1aaf1b-09b3-48c9-82ed-fa3a46cc56b2@gmail.com>
Denis Kenzior <denkenz@gmail.com> writes:
> Hi Toke,
>
> On 11/24/23 05:58, Toke Høiland-Jørgensen wrote:
>> Hi
>>
>> When setting AddressRandomization=network in main.conf, I am unable to
>> connect to networks because I don't get a DHCP reply after the L2
>> connection.
>>
>> Looking at a packet dump, it seems the DHCP request uses the wrong
>> source MAC in the request:
>>
>
> Can you try the following patch on the ell mailing list? Here's the patchwork
> link in case you're not subscribed:
> https://patchwork.kernel.org/project/ell/patch/20231124161740.1243946-1-denkenz@gmail.com/
Yup, that resolves the issue so that I can connect. However, this is the
DHCP packets I see when moving between two networks (back and forth):
17:49:59.040639 1e:aa:ca:6d:0d:e0 > 92:0a:9a:27:ca:65, ethertype IPv4 (0x0800), length 342: 10.42.3.52.68 > 10.42.3.33.67: BOOTP/DHCP, Request from 1e:aa:ca:6d:0d:e0, length 300
17:49:59.392682 ba:06:75:75:30:90 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from ba:06:75:75:30:90, length 300
17:49:59.396012 e6:49:86:36:22:bf > ba:06:75:75:30:90, ethertype IPv4 (0x0800), length 335: 10.42.3.97.67 > 10.42.3.102.68: BOOTP/DHCP, Reply, length 293
17:49:59.396167 ba:06:75:75:30:90 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from ba:06:75:75:30:90, length 300
17:49:59.397811 e6:49:86:36:22:bf > ba:06:75:75:30:90, ethertype IPv4 (0x0800), length 335: 10.42.3.97.67 > 10.42.3.102.68: BOOTP/DHCP, Reply, length 293
17:50:03.306455 ba:06:75:75:30:90 > e6:49:86:36:22:bf, ethertype IPv4 (0x0800), length 342: 10.42.3.102.68 > 10.42.3.97.67: BOOTP/DHCP, Request from ba:06:75:75:30:90, length 300
17:50:03.614293 1e:aa:ca:6d:0d:e0 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 1e:aa:ca:6d:0d:e0, length 300
17:50:03.619009 92:0a:9a:27:ca:65 > 1e:aa:ca:6d:0d:e0, ethertype IPv4 (0x0800), length 359: 10.42.3.33.67 > 10.42.3.52.68: BOOTP/DHCP, Reply, length 317
17:50:03.619085 1e:aa:ca:6d:0d:e0 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 1e:aa:ca:6d:0d:e0, length 300
17:50:03.620141 92:0a:9a:27:ca:65 > 1e:aa:ca:6d:0d:e0, ethertype IPv4 (0x0800), length 359: 10.42.3.33.67 > 10.42.3.52.68: BOOTP/DHCP, Reply, length 317
As you can see, in each case, there's an initial unicast request that
contains the old MAC and IP. Which seems to be a bit counter productive
if this is supposed to be a privacy feature that doesn't leak addresses
across networks? :)
-Toke
next prev parent reply other threads:[~2023-11-24 16:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-24 11:58 Wrong source MAC for DHCP requests with AddressRandomization=network Toke Høiland-Jørgensen
2023-11-24 16:23 ` Denis Kenzior
2023-11-24 16:53 ` Toke Høiland-Jørgensen [this message]
2023-11-24 17:09 ` Denis Kenzior
2023-11-24 17:51 ` Toke Høiland-Jørgensen
2023-11-24 19:21 ` Rhys Perry
2023-11-25 23:30 ` Denis Kenzior
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