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WireGuard / wgctrl-go

Package wgctrl enables control of WireGuard interfaces on multiple platforms.
https://godoc.org/golang.zx2c4.com/wireguard/wgctrl
MIT License
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Peer endpoint port is not packed correctly #15

Closed apognu closed 5 years ago

apognu commented 5 years ago

Hi,

The port of a peer endpoint seems to be transmitted incorrectly to netlink, here are the values set in the PeerConfig (left) struct and the resulting value as reported by wg (right) after calling ConfigureDevice:

mdlayher commented 5 years ago

I don't believe this is the actual problem; when spelunking through wg code, I noticed it was making a system call ("getnameinfo"? IIRC) to resolve the endpoint address in some way. I forgot to look into it further, but this issue is a good reminder to do so.

However it's totally possible that I missed something, and maybe my unsafe cast isn't quite right.

apognu commented 5 years ago

wg is not the only tool reporting the wrong port. My own tools (in Python and Go) do as well.

And the issue appeared as soon as I migrated from directly using genetlink to wireguardctrl.

mdlayher commented 5 years ago

I'll take a look today, but PRs welcome if you find it first. This sounds like an endianness issue.

apognu commented 5 years ago

I think you're reversing the two bytes of the port number.

10000 is 00100111 00010000 in binary. 4135 is 00010000 00100111

So yes, endianness issue probably. I'll look if I can find the issue.

mdlayher commented 5 years ago

Should be fixed as of #16.

mdlayher commented 5 years ago

Seems to work as expected now:

        cfg := wgtypes.Config{
            ReplacePeers: true,
            Peers: []wgtypes.PeerConfig{{
                PublicKey: priv.PublicKey(),
                Endpoint: &net.UDPAddr{
                    IP:   net.IPv4(192, 168, 1, 4),
                    Port: 58575,
                },
            }},
        }

        if err := c.ConfigureDevice(d.Name, cfg); err != nil {
            log.Fatalf("failed to configure: %v", err)
        }
$ sudo ./wgctrl 
interface: wg0
  public key: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
  private key: (hidden)
  listening port: 0

peer: R65jHoT6fhrk8OFS/L2KiDEP/O/+XrCGfOGzUG3x1j0=
  endpoint: 192.168.1.4:58575
  allowed ips: 
  latest handshake: 1969-12-31 19:00:00 -0500 EST
  transfer: 0 B received, 0 B sent
apognu commented 5 years ago

Yes, everything's good on my end as well.