Node: os.networkInterfaces() returns wrong MAC addresses

[mattbrun]

• Version: 8.1.0
• Platform: linux
• Subsystem: os

os.networkInterfaces() returns wrong MAC addresses.

Running the following code

console.log('interfaces ####################\n',
  require('os').networkInterfaces())
console.log('ip a ####################\n',
  require('child_process').execSync('ip a').toString().trim())

I get the following output

interfaces ####################
 { lo: 
   [ { address: '127.0.0.1',
       netmask: '255.0.0.0',
       family: 'IPv4',
       mac: '00:00:00:00:00:00',
       internal: true },
     { address: '::1',
       netmask: 'ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff',
       family: 'IPv6',
       mac: '00:00:00:00:00:00',
       scopeid: 0,
       internal: true } ],
  enp3s0f1: 
   [ { address: '192.168.1.116',
       netmask: '255.255.255.0',
       family: 'IPv4',
       mac: '00:00:00:00:41:00',
       internal: false },
     { address: 'fe80::4100:1991:751a:d1aa',
       netmask: 'ffff:ffff:ffff:ffff::',
       family: 'IPv6',
       mac: '00:00:00:00:41:00',
       scopeid: 2,
       internal: false } ] }
ip a ####################
 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp3s0f1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 70:4d:7b:3c:16:b0 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.116/24 brd 192.168.1.255 scope global dynamic enp3s0f1
       valid_lft 1076sec preferred_lft 1076sec
    inet6 fe80::4100:1991:751a:d1aa/64 scope link 
       valid_lft forever preferred_lft forever
165: wlp2s0mon: <BROADCAST,ALLMULTI,PROMISC,NOTRAILERS,UP,LOWER_UP> mtu 1500 qdisc mq state UNKNOWN group default qlen 1000
    link/ieee802.11/radiotap d0:57:7b:0e:93:31 brd ff:ff:ff:ff:ff:ff

This a small tabble with some experiments I did playing with node versions and platforms

| Version | OS | Platform | Output |
| --- | --- | --- | --- |
| 8.1.0 | linux | PC | wrong |
| 7.10.0 | linux | RaspberryPi 3 | wrong |
| 4.8.3 | linux | PC | correct |
| 4.4.3 | linux | RaspberryPi 3 | correct |

I'm no expert of nodejs core, but my feeleing is that maybe libuv returns a wrong MAC address... Is it maybe related to https://github.com/libuv/libuv/issues/829 ?

Thanks for your help, and all the hard work you're doing!
Kind regards,
M.

[XadillaX]

I've created a PR for this bug in libuv. After that PR done, we can upgrade libuv in Node.js.

[mattbrun]

Thanks a lot!

[oxygen]

On CentOS 7.2, node 8.0.0 and every 7.x version I have tried works fine.

However, when switching to node 8.1.0 the MAC addresses are wrong and always begin with 00:00:00:00:xx:xx.

I have reproduced this with two fresh installs in VMware on two different hosts.

Is there any other way I can help with this?

[XadillaX]

@oxygen Yes, This bug appears on the newer version of libuv. Node.js 8.x failed because of the updating of libuv. And I've already create a PR to fix this issue on libuv (https://github.com/libuv/libuv/issues/1375). After that PR done, we can upgrade libuv in Node.js.

Maybe you can give some suggest to that PR.

[targos]

Reopening because the fix only landed in libuv.

[XadillaX]

@bnoordhuis Shall I wait for new version of libuv releases, or just patch the bugfix code into Node.js master?

[bnoordhuis]

Just wait for the upgrade, we never float libuv patches.

[XadillaX]

14866 will fix this issue. (via https://github.com/libuv/libuv/commit/f1e0fc43d17d9f2d16b6c4f9da570a4f3f6063ed)