net: Automatically create hidden service, listen on Tor #6639

laanwj · 2015-09-04T15:43:04Z

Discussion in #6586.

Starting with Tor version 0.2.7.1 it is possible, through Tor's control socket API, to create and destroy 'ephemeral' hidden services programmatically.
https://stem.torproject.org/api/control.html#stem.control.Controller.create_ephemeral_hidden_service

This means that if Tor is running (and proper authorization is available), bitcoin automatically creates a hidden service to listen on, without user manual configuration. This will positively affect the number of available .onion nodes.

When the node is started, connect to Tor through control socket
Send ADD_ONION command
First time:
- Make it create a hidden service key
- Save the key in the data directory for later usage
Make it redirect port 8333 to the local port 8333 (or whatever port we're listening on).
Keep control socket connection open for as long node is running. The hidden service will
(by default) automatically go away when the connection is closed.

Adds command line options:

-listenonion Automatically create Tor hidden service (default: 1)
-torcontrol=<ip>:<port> "Tor control port to use if onion listening enabled (default: 127.0.0.1:9051)

TODO:

SAFECOOKIE authentication support (see discussion in Automatically create hidden service, listen on Tor #6586)
HASHEDPASSWORD authentication: manually provide Tor credentials
Logging: most of the more specific logging should go into a debug category

jgarzik · 2015-09-15T23:27:52Z

I like the feature - concept ACK

Trying to think through whether there are edge cases that persuade us to default this 'off' Leaning towards default-on as presented.

dcousens · 2015-09-16T07:09:51Z

concept ACK

btcdrak · 2015-09-23T19:55:12Z

concept ACK

sipa · 2015-09-26T00:07:35Z

2015-09-26 00:03:11 [tor] Using COOKIE authentication, reading cookie authentication from /var/run/tor/control.authcookie
2015-09-26 00:03:11 [tor] Authentication cookie not found, is inaccessible, or is not exactly 64 bytes

I have ControlPort 9051 and CookieAuthentication in torrc.

pstratem · 2015-09-26T00:23:25Z

Check the permissions
On Sep 25, 2015 5:07 PM, "Pieter Wuille" notifications@github.com wrote:

2015-09-26 00:03:11 [tor] Using COOKIE authentication, reading cookie
authentication from /var/run/tor/control.authcookie
2015-09-26 00:03:11 [tor] Authentication cookie not found, is
inaccessible, or is not exactly 64 bytes

I have ControlPort 9051 and CookieAuthentication in torrc.

—
Reply to this email directly or view it on GitHub
#6639 (comment).

laanwj · 2015-10-02T12:25:51Z

@sipa the check was broken, the cookie is 32 bytes not 64. That said, we should have a more specific error message.

theuni · 2015-10-02T15:24:04Z

src/torcontrol.cpp

+    if (f == NULL)
+        return false;
+    if (fwrite(data.data(), 1, data.size(), f) != data.size())
+        return false;


false case needs fclose too

oops good catch

theuni · 2015-10-02T15:54:15Z

Can the shutdown detection be changed to work like the httpserver? ie Init calls InterruptTorControl() which starts the immediate shutdown process?

theuni · 2015-10-02T16:26:06Z

src/torcontrol.cpp

+
+bool TorControlConnection::Disconnect()
+{
+    if (b_conn)


Need to undo the AddLocal here?

theuni · 2015-10-02T16:43:00Z

(Not for this PR) Looks like it'd be pretty simple to add support for connecting via Unix socket (/var/run/tor/control) as well.

theuni · 2015-10-02T16:45:20Z

Concept ACK. This looks like a great feature.

laanwj · 2015-10-03T09:57:45Z

@cfields

Can the shutdown detection be changed to work like the httpserver? ie Init calls InterruptTorControl() which starts the immediate shutdown process?

Yes, that sounds better. I have not done this before because it means making the libevent instance thread-safe - Interrupt happens from a different thread. But as we need multi-threaded libevent anyway from the http server that's a bad reason.

(Not for this PR) Looks like it'd be pretty simple to add support for connecting via Unix socket (/var/run/tor/control) as well.

Good idea.

laanwj · 2015-10-03T15:26:49Z

Ok: addressed all of @theuni's comments (apart from the UNIX socket, which we can add later).
Still have SAFECOOKIE auth support on my TODO list above, it is superior to COOKIE (no potential exposure of data), and COOKIE will eventually be deprecated.
This does require use of HMAC-SHA256. Luckily we have an implementation of that for BIP32, so I think it's doable.

Edit: done

Starting with Tor version 0.2.7.1 it is possible, through Tor's control socket API, to create and destroy 'ephemeral' hidden services programmatically. https://stem.torproject.org/api/control.html#stem.control.Controller.create_ephemeral_hidden_service This means that if Tor is running (and proper authorization is available), bitcoin automatically creates a hidden service to listen on, without user manual configuration. This will positively affect the number of available .onion nodes. - When the node is started, connect to Tor through control socket - Send `ADD_ONION` command - First time: - Make it create a hidden service key - Save the key in the data directory for later usage - Make it redirect port 8333 to the local port 8333 (or whatever port we're listening on). - Keep control socket connection open for as long node is running. The hidden service will (by default) automatically go away when the connection is closed.

laanwj · 2015-11-10T17:07:17Z

Also mentioned in release notes now.

petertodd · 2015-11-10T20:30:07Z

ACK

Tests done:

Restart reuses cached onion private key
SAFECOOKIE auth
HASHEDPASSWORD auth
Onion advertisement stops with tor disconnects
Onion advertisement starts when tor restarted

sipa · 2015-11-11T07:53:58Z

No code review, did a weak test (it correctly reports my Tor version is too old).

maflcko · 2015-11-11T12:50:08Z

That's great! I will try to look into this soon.

petertodd · 2015-11-11T18:06:15Z

utACK squashme commits

maflcko · 2015-11-11T22:41:44Z

src/torcontrol.cpp

+        service = CService(service_id+".onion", GetListenPort(), false);
+        LogPrintf("tor: Got service ID %s, advertizing service %s\n", service_id, service.ToString());
+        if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) {
+            LogPrint("tor", "tor: Cached service private key to %s\n", GetPrivateKeyFile());


~~Nit: "Wrote service key..."?~~

Also, mind to pass this file through

contrib/devtools/clang-format.py clang-format src/torcontrol.cpp?

Nit: Please update https://github.com/bitcoin/bitcoin/blob/master/doc/files.md

maflcko · 2015-11-11T22:57:24Z

Somehow I can set up a -onlynet=onion node and connect to it (sometimes) but it never established outgoing connections:

2015-11-11 22:05:45 tor: ADD_ONION succesful
2015-11-11 22:05:45 tor: Got service ID moheur3skn7jbca4, advertizing service moheur3skn7jbca4.onion:18333
2015-11-11 22:05:45 tor: Cached service private key to /home/test/.bitcoin/testnet3/onion_private_key
2015-11-11 22:05:45 AddLocal(moheur3skn7jbca4.onion:18333,4)
2015-11-11 22:05:46 Cannot connect to t6xj6wilh4ytvcs7.onion:18333: unsupported network
2015-11-11 22:05:46 Cannot connect to 4azvkpo55qaskhjl.onion:18333: unsupported network
2015-11-11 22:05:47 Cannot connect to nkf5e6b7pl4jfd4a.onion:18333: unsupported network
2015-11-11 22:05:48 Cannot connect to 4zhkir2ofl7orfom.onion:18333: unsupported network

gits7r · 2015-11-11T23:56:48Z

you are mistaking. it's -onlynet=tor . you confuse onion with -onion=127.0.0.1:9050 where you instruct bitcoin to use that socks5 proxy to connect to onion peers (from tor network). While -onlynet=tor will make sure you connect only to onion (Tor) peers, -onion=xxx will only provide a gateway for these peers but connect to other kind of peers also.

maflcko · 2015-11-12T07:15:34Z

Then, why does -? doesn't even mention tor?

  -onlynet=<net>
       Only connect to nodes in network <net> (ipv4, ipv6 or onion)

laanwj · 2015-11-12T07:29:50Z

onlynet=onion should work. But is unrelated to this pull. Did you pass a proxy?

maflcko · 2015-11-12T07:48:03Z

I tried with and without proxy:
bitcoin/src/bitcoind -debug=tor -onlynet=onion -proxy=127.0.0.1:9050 -listen=1 -torpassword=bar

But maybe my VPS provider is blocking tor...

laanwj · 2015-11-12T07:54:01Z

They could, but that whouldn't result in errors like

2015-11-11 22:05:46 Cannot connect to t6xj6wilh4ytvcs7.onion:18333: unsupported network

Instead you'd get proxy errors. It's not using the proxy, why is that (again, this is seemingly unrleated to this pull, maybe file a new issue)

- Force AUTHCOOKIE size to be 32 bytes: This provides protection against an attack where a process pretends to be Tor and uses the cookie authentication method to nab arbitrary files such as the wallet - torcontrol logging - fix cookie auth - add HASHEDPASSWORD auth, fix fd leak when fwrite() fails - better error reporting when cookie file is not ok - better init/shutdown flow - stop advertizing service when disconnected from tor control port - COOKIE->SAFECOOKIE auth

- add new data directory files for 0.12 to doc/files.md - mention torcontrol in doc/tor.md

58ef0ff doc: update docs for Tor listening (Wladimir J. van der Laan) 68ccdc4 doc: Mention Tor listening in release notes (Wladimir J. van der Laan) 09c1ae1 torcontrol improvements and fixes (Wladimir J. van der Laan) 2f796e5 Better error message if Tor version too old (Peter Todd) 8f4e67f net: Automatically create hidden service, listen on Tor (Wladimir J. van der Laan)

maflcko · 2015-11-12T18:37:06Z

tested ACK 58ef0ff

laanwj added the P2P label Sep 4, 2015

laanwj force-pushed the 2015_08_tor_hs_v2 branch from 6adfb50 to 4ed85cf Compare October 2, 2015 12:25

theuni reviewed Oct 2, 2015
View reviewed changes

src/torcontrol.cpp

bool TorControlConnection::Disconnect()

{

if (b_conn)

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Need to undo the AddLocal here?

laanwj and others added 2 commits November 10, 2015 17:29

Better error message if Tor version too old

2f796e5

laanwj force-pushed the 2015_08_tor_hs_v2 branch from 93221f9 to 583d9bf Compare November 10, 2015 16:33

maflcko reviewed Nov 11, 2015
View reviewed changes

laanwj added 2 commits November 12, 2015 17:58

doc: Mention Tor listening in release notes

68ccdc4

laanwj force-pushed the 2015_08_tor_hs_v2 branch 2 times, most recently from 944fcca to 58ef0ff Compare November 12, 2015 17:08

doc: update docs for Tor listening

58ef0ff

- add new data directory files for 0.12 to doc/files.md - mention torcontrol in doc/tor.md

laanwj merged commit 58ef0ff into bitcoin:master Nov 12, 2015

laanwj mentioned this pull request Nov 16, 2015

Automatically create hidden service, listen on Tor #6586

Closed

petertodd mentioned this pull request Nov 24, 2015

Connect to Tor hidden services by default #7090

Merged

str4d mentioned this pull request Jun 14, 2016

Figure out how upstream Tor integration works, then interactively test it. zcash/zcash#917

Closed

str4d mentioned this pull request Jan 5, 2017

Merge libevent-based http server from Bitcoin for better stability in RPC zcash/zcash#1593

Closed

daira mentioned this pull request Feb 2, 2017

Merge upstream support for Tor ephemeral hidden services zcash/zcash#2061

Closed

str4d mentioned this pull request Mar 14, 2017

Tor ephemeral hidden services zcash/zcash#2177

Merged

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net: Automatically create hidden service, listen on Tor #6639

net: Automatically create hidden service, listen on Tor #6639

laanwj commented Sep 4, 2015

jgarzik commented Sep 15, 2015

dcousens commented Sep 16, 2015

btcdrak commented Sep 23, 2015

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net: Automatically create hidden service, listen on Tor #6639

net: Automatically create hidden service, listen on Tor #6639

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laanwj commented Sep 4, 2015

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