tinc-1.1pre10 seems to be broken on Windows

[Etienne Dechamps]

Hi,

I was previously using tinc-1.1pre8 and it worked just fine, but after 
upgrading to tinc-1.1pre10 my Windows machine is unable to connect to my 
tinc network, as it fails to complete the handshake.

Steps to reproduce:
- Set up a Linux node with tinc-1.1pre10 using "tinc init"
- Set up a Windows node with tinc-1.1pre10 using "tinc init", and try to 
make it connect to the Linux node

The Windows node will be unable to connect. Here's an example with 
"pegasus" as the Windows (client) node and "zyklos" as the Linux 
(server) node:

### pegasus (Windows) SIDE ###

tincd 1.1pre10 (Feb  7 2014 22:45:15) starting, debug level 5
{79D0E1D7-EAA8-442D-BC16-E4FBAEA3E3C2} (Longcat) is a Windows tap device
Tap reader running
Listening on :: port 655
Listening on 0.0.0.0 port 655
Ready
Trying to connect to zyklos (10.172.1.1 port 655)
Connected to zyklos (10.172.1.1 port 655)
Sending ID to zyklos (10.172.1.1 port 655): 0 pegasus 17.3
Sending 15 bytes of metadata to zyklos (10.172.1.1 port 655)
Got ID from zyklos (10.172.1.1 port 655): 0 zyklos 17.3
Broadcasting packet of 149 bytes from pegasus (MYSELF port 655)
Sending ACK to zyklos (10.172.1.1 port 655): 4 655 24 300000c
Sending 17 bytes of metadata to zyklos (10.172.1.1 port 655)
Error while decrypting: error:00000000:lib(0):func(0):reason(0)
Failed to decrypt record
Closing connection with zyklos (10.172.1.1 port 655)
Could not set up a meta connection to zyklos

### zyklos (Linux) SIDE ###

tincd 1.1pre10 (Jun 21 2014 11:54:28) starting, debug level 5
/dev/net/tun is a Linux tun/tap device (tun mode)
Listening on 0.0.0.0 port 655
Listening on :: port 655
Executing script tinc-up
Unconfigured tinc-up script, please edit 
/usr/local/tinc/etc/tinc/sandbox/tinc-up!
Ready
Connection from 10.172.1.2 port 12976
Sending ID to <unknown> (10.172.1.2 port 12976): 0 zyklos 17.3
Sending 14 bytes of metadata to <unknown> (10.172.1.2 port 12976)
Got ID from <unknown> (10.172.1.2 port 12976): 0 pegasus 17.3
Sending ACK to pegasus (10.172.1.2 port 12976): 4 655 17 300000c
Sending 17 bytes of metadata to pegasus (10.172.1.2 port 12976)
Got ACK from pegasus (10.172.1.2 port 12976): 4 655 24 300000c
Connection with pegasus (10.172.1.2 port 12976) activated
Sending ADD_EDGE to everyone (BROADCAST): 12 340155a3 zyklos pegasus 
10.172.1.2 655 300000c 20
Sending 53 bytes of metadata to pegasus (10.172.1.2 port 12976)
Connection closed by pegasus (10.172.1.2 port 12976)
Closing connection with pegasus (10.172.1.2 port 12976)

Additional information:
  - I can confirm that zyklos (Linux) behaves correctly: if I connect to 
it from another Linux node it works fine (and the other way as well). 
Therefore the problems seems to be on pegasus (Windows) side.
  - Both sides are using freshly generated keys. Generating the Windows 
keys on the Linux box does not solve the problem, so it doesn't seem to 
be a problem with key generation.
  - The error message points strongly to a problem with the keys 
themselves, but I triple-checked that everything was consistent (no 
mixing of public/private keys and checksum-identical public key files on 
both sides).
  - On zyklos (Linux), tinc was compiled from source from the 
"release-1.1pre10" git tag. On pegasus (Windows) tinc was installed from 
the downloadable package.
  - From where I'm standing this looks like a Windows-only regression 
between 1.1pre8 and 1.1pre10.

-- 
Etienne Dechamps