Fix a bug in socks5 when rendering remote address

[jieyu]

When the remote address is an IP address, we cannot directly convert
byte array to string. Otherwise, we will see hex strings like
"\xac\x11\x01\xc8:443".

See more details about the bug in:
https://community.gravitational.com/t/ssh-dynamic-port-forwarding-not-working/432

The above reported issue is resolved after applying the patch.

[gravitational-jenkins]

Can one of the admins verify this patch?

[webvictim]

ok to test

[jieyu]

hum, I cannot see test logs. Can someone check for me?

[webvictim]

@jieyu

FAIL: socks_test.go:48: SOCKSSuite.TestHandshake

socks_test.go:69:
    c.Assert(string(buf), check.Equals, remoteAddr)
... obtained string = "?6578616d706c65"
... expected string = "example.com:443"

OOPS: 0 passed, 1 FAILED
--- FAIL: TestSocks (0.01s)

[jieyu]

OK, i'll fix. I think we should distinguish between DNS name and IP addresses.

[jieyu]

@webvictim can you take another look? I updated the code and the test.

[jieyu]

ping @klizhentas @russjones

[webvictim]

Looks like the test passes now @jieyu - the integration test is failing but that's probably unrelated.

[jieyu]

@webvictim how can I get this bug fix reviewed and merged? This is blocking our progress

[klizhentas]

Thanks for your patience. We are currently overloaded with requests. We will get to this issue in the context of 4.2 milestone in a couple of weeks from now.

[webvictim]

@jieyu You can always build Teleport yourself from source with your patch included if you like.

[jieyu]

@webvictim we could, but that means our customers will have to use a forked version of teleport, which I am trying to avoid. This is clearly a bug, so I expect not too much trouble merging this.

[klizhentas]

@russjones can you please review sometime this week?

[klizhentas]

@jieyu the fix looks quite straightforward to me, we will try to wrap up the review this week. What version are you using?

[jieyu]

@klizhentas thanks for the review! we're using the latest. So if this can be included in the upcoming release, that'll be sufficient.

[klizhentas]

sounds good to me, thank you for the patch.