diff --git a/doc/tor.md b/doc/tor.md index d9ddb87e2..78b8f010e 100644 --- a/doc/tor.md +++ b/doc/tor.md @@ -1,149 +1,289 @@ -*** Warning: Do not assume Tor support does the correct thing in Zcash; better Tor support is a future feature goal. *** - -TOR SUPPORT IN ZCASH +Tor Support in Zcash ==================== -It is possible to run Zcash as a Tor hidden service, and connect to such services. +Tor can be used to provide a layer of network anonymity for Zcash users. +Additionally, Zcash users may chose to connect only to Tor hidden services, and +also to expose their own Tor hidden service to allow users to connect to them +over the Tor network. -The following directions assume you have a Tor proxy running on port 9050. Many distributions default to having a SOCKS proxy listening on port 9050, but others may not. In particular, the Tor Browser Bundle defaults to listening on port 9150. See [Tor Project FAQ:TBBSocksPort](https://www.torproject.org/docs/faq.html.en#TBBSocksPort) for how to properly -configure Tor. +0. Install Tor +-------------- + +The easiest way to install Tor is to use the +[Tor Browser Bundle](https://www.torproject.org/download/). For headless +installs, you probably want to install the Tor daemon. The Tor Project +provides [instructions](https://support.torproject.org/apt/) for doing this on +common Linux distributions. Note that the Tor Browser Bundle exposes a SOCKS +listener on tcp/9150 by default, while the Tor daemon exposes the SOCKS +listener on tcp/9050. For the purposes of the example below, we'll assume that +you're using the Tor daemon and that the SOCKS listener is on tcp/9050. + +1. Run zcashd over Tor +---------------------- + +Configuring zcashd to use a Tor SOCKS proxy will route all outgoing connections +over Tor. + +```bash +$ zcashd -proxy=127.0.0.1:9050 +``` + +Yay! Your zcashd node is now leveraging the Tor network to connect to other +zcashd nodes. But there's more fun to be had. By creating a +[Tor Hidden Service](https://2019.www.torproject.org/docs/faq.html.en#TorOnionServices). +you can help promote privacy for Zcash users by advertising your node's .onion +address to other Tor Zcash users. + +2. Expose your zcashd via a Tor hidden service (optional) +--------------------------------------------------------- + +Edit your /etc/tor/torrc (or equivalent config file) to map the hidden service +to your zcashd TCP listener. The directory can be whatever you like but the +port numbers should be equal to the zcashd p2p listen port (8233 by default). +An example is below. + +```yaml +############### This section is just for location-hidden services ### + +## Once you have configured a hidden service, you can look at the +## contents of the file ".../hidden_service/hostname" for the address +## to tell people. +## +## HiddenServicePort x y:z says to redirect requests on port x to the +## address y:z. + +# +# Placeholder for when zcashd adds support for Onion v3 addresses +#HiddenServiceDir /var/lib/tor/zcash_hidden_service_v3/ +#HiddenServiceVersion 3 +#HiddenServicePort 8233 127.0.0.1:8233 + +# use the generated v2 Onion hostname until v3 support is complete +HiddenServiceDir /var/lib/tor/zcash_hidden_service_v2/ +HiddenServiceVersion 2 +HiddenServicePort 8233 127.0.0.1:8233 +``` + +Note that zcashd does not yet support Onion v3 addresses, but will do so before +v2 addresses are removed from Tor. See [this +issue](https://github.com/zcash/zcash/issues/3051) for more information on +what's required to make zcashd support v3 Onion addresses. + +After making these edits to /etc/tor/torrc, restart tor to create the hidden +service hostname and keys. + +```bash +$ sudo systemctl restart tor +``` + +Then set a bash variable to provide your Onion service hostname to zcashd so it +can advertise your node to other Tor capable nodes on the Zcash network. + +```bash +$ export MY_ONION_HOSTNAME=`sudo cat /var/lib/tor/zcash_hidden_service_v2/hostname` +``` + +Now configure the zcashd node to use the Tor proxy, enable the TCP listener +(only on localhost), and advertise your onion address so that other nodes on +the Zcash network can connect to you over Tor. + +```bash +$ zcashd -proxy=127.0.0.1:9050 -externalip=$MY_ONION_HOSTNAME -listen -bind=127.0.0.1 -listenonion=0 +``` +zcashd flags used: + +- `-proxy=ip:port`: sets the proxy server. This must match the port IP and port + on which your Tor listener is configured. +- `-externalip=`: sets the publicly routable address that zcashd will + advertise to other zcash nodes. This can be an IPv4, IPv6 or .onion address. + Onion addresses are given preference for advertising and connections. Onionv3 + addresses are [not yet supported](https://github.com/zcash/zcash/issues/3051). +- `-listen`: Enable listening for incoming connections with this flag; + listening is off by default, but is needed in order for Tor to connect to + zcashd. +- `-bind=ip`: Bind (only) to this IP. Will bind to all interfaces by default + if ``listen=1``. +- `-listenonion=<0|1>`: Enable or disable autoconfiguration of Tor hidden + service via control socket API. Disabled in this example because we manually + configured the hidden service in /etc/tor/torrc. + +Once your node is up and running, you can use `zcash-cli` to verify that it +is properly connected to other Zcash nodes over the p2p network, and is +correctly advertising its Onion address to the network. + +```bash +$ zcash-cli getnetworkinfo +``` + +```javascript +{ + "version": 4020050, + "subversion": "/MagicBean:4.2.0/", + "protocolversion": 170013, + "connections": 9, + "networks": [ + { + "name": "ipv4", + "limited": true, + "reachable": false, + "proxy": "127.0.0.1:9050", + "proxy_randomize_credentials": true + }, + { + "name": "ipv6", + "limited": true, + "reachable": false, + "proxy": "127.0.0.1:9050", + "proxy_randomize_credentials": true + }, + { + "name": "onion", + "limited": false, + "reachable": true, + "proxy": "127.0.0.1:9050", + "proxy_randomize_credentials": true + } + ], + "relayfee": 0.00000100, + "localaddresses": [ + { + "address": "ynizm2wpla6ec22q.onion", + "port": 8233, + "score": 10 + } + ], +} +``` -1. Run Zcash behind a Tor proxy -------------------------------- - -The first step is running Zcash behind a Tor proxy. This will already make all -outgoing connections be anonymized, but more is possible. - - -proxy=ip:port Set the proxy server. If SOCKS5 is selected (default), this proxy - server will be used to try to reach .onion addresses as well. - - -onion=ip:port Set the proxy server to use for Tor hidden services. You do not - need to set this if it's the same as -proxy. You can use -noonion - to explicitly disable access to hidden service. - - -listen When using -proxy, listening is disabled by default. If you want - to run a hidden service (see next section), you'll need to enable - it explicitly. - - -connect=X When behind a Tor proxy, you can specify .onion addresses instead - -addnode=X of IP addresses or hostnames in these parameters. It requires - -seednode=X SOCKS5. In Tor mode, such addresses can also be exchanged with - other P2P nodes. - -In a typical situation, this suffices to run behind a Tor proxy: - - ./zcashd -proxy=127.0.0.1:9050 - - -2. Run a Zcash hidden server ----------------------------- - -If you configure your Tor system accordingly, it is possible to make your node also -reachable from the Tor network. Add these lines to your /etc/tor/torrc (or equivalent -config file): - - HiddenServiceDir /var/lib/tor/zcash-service/ - HiddenServicePort 8233 127.0.0.1:8233 - HiddenServicePort 18233 127.0.0.1:18233 - -The directory can be different of course, but (both) port numbers should be equal to -your zcashd's P2P listen port (8233 by default). - - -externalip=X You can tell Zcash about its publicly reachable address using - this option, and this can be a .onion address. Given the above - configuration, you can find your onion address in - /var/lib/tor/zcash-service/hostname. Onion addresses are given - preference for your node to advertize itself with, for connections - coming from unroutable addresses (such as 127.0.0.1, where the - Tor proxy typically runs). - - -listen You'll need to enable listening for incoming connections, as this - is off by default behind a proxy. - - -discover When -externalip is specified, no attempt is made to discover local - IPv4 or IPv6 addresses. If you want to run a dual stack, reachable - from both Tor and IPv4 (or IPv6), you'll need to either pass your - other addresses using -externalip, or explicitly enable -discover. - Note that both addresses of a dual-stack system may be easily - linkable using traffic analysis. - -In a typical situation, where you're only reachable via Tor, this should suffice: - - ./zcashd -proxy=127.0.0.1:9050 -externalip=zctestseie6wxgio.onion -listen - -(obviously, replace the Onion address with your own). It should be noted that you still -listen on all devices and another node could establish a clearnet connection, when knowing -your address. To mitigate this, additionally bind the address of your Tor proxy: - - ./zcashd ... -bind=127.0.0.1 - -If you don't care too much about hiding your node, and want to be reachable on IPv4 -as well, use `discover` instead: - - ./zcashd ... -discover - -and open port 8233 on your firewall (or use -upnp). - -If you only want to use Tor to reach onion addresses, but not use it as a proxy -for normal IPv4/IPv6 communication, use: - - ./zcashd -onion=127.0.0.1:9050 -externalip=zctestseie6wxgio.onion -discover - - -3. Automatically listen on Tor --------------------------------- +3. Dynamically Configure Onion Service (Optional) +------------------------------------------------- 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. -Zcash has been updated to make use of this. +API, to create and destroy 'ephemeral' hidden services programmatically. zcashd +has been updated to make use of this. -This means that if Tor is running (and proper authentication has been configured), -Zcash automatically creates a hidden service to listen on. Zcash will also use Tor +This configuration could be used instead of manually configuring the Onion +service as in step 2 above. + +If Tor is running (and proper authentication has been configured), zcashd +automatically creates a hidden service to listen on. zcashd will also use Tor automatically to connect to other .onion nodes if the control socket can be -successfully opened. This will positively affect the number of available .onion -nodes and their usage. +successfully opened. -This new feature is enabled by default if Zcash is listening (`-listen`), and -requires a Tor connection to work. It can be explicitly disabled with `-listenonion=0` -and, if not disabled, configured using the `-torcontrol` and `-torpassword` settings. -To show verbose debugging information, pass `-debug=tor`. +This new feature is enabled by default if zcashd is listening (`-listen`) and +requires a Tor connection to work. It can be explicitly disabled with +`-listenonion=0` and, if not disabled, configured using the `-torcontrol` +and `-torpassword` settings. To show verbose debugging information, pass +`-debug=tor`. -Connecting to Tor's control socket API requires one of two authentication methods to be -configured. For cookie authentication the user running zcashd must have write access -to the `CookieAuthFile` specified in Tor configuration. In some cases this is -preconfigured and the creation of a hidden service is automatic. If permission problems -are seen with `-debug=tor` they can be resolved by adding both the user running tor and -the user running zcashd to the same group and setting permissions appropriately. On -Debian-based systems the user running zcashd can be added to the debian-tor group, -which has the appropriate permissions. An alternative authentication method is the use -of the `-torpassword` flag and a `hash-password` which can be enabled and specified in -Tor configuration. +Connecting to Tor's control socket API requires one of two authentication +methods to be configured: +1. Cookie authentication, which requires write access to the `CookieAuthFile` + specified in Tor configuration. In some cases, this is preconfigured and the + creation of a hidden service is automatic. If permission problems are seen + with `-debug=tor` they can be resolved by adding both the user running tor + and the user running zcashd to the same group and setting permissions + appropriately. On Debian-based systems the user running zcashd can be added + to the debian-tor group, which has the appropriate permissions. +2. Authentication with the `-torpassword` flag and a `hash-password`, which + can be enabled and specified in Tor configuration. -4. Connect to a Zcash hidden server ------------------------------------ +On Debian systems, where Tor is installed via APT, you can trivially permit +zcashd to connect to the Tor socket by adding the zcash user to the +`debian-tor` group. -To test your set-up, you might want to try connecting via Tor on a different computer to just a -a single Zcash hidden server. Launch zcashd as follows: +```bash +$ sudo usermod -aG debian-tor zcash +``` + +When properly configured, this will allow zcashd to automatically connect to +the Tor control socket API and configure an ephemeral hidden service. + +```bash +$ zcashd -debug=tor +``` + +``` +Feb 11 15:26:20.323 INFO main: tor: Got service ID tweustb4j6o3u5x7, advertizing service tweustb4j6o3u5x7.onion:8233 +Feb 11 15:26:20.323 DEBUG tor: tor: Cached service private key to /home/zcash/.zcash/onion_private_key +Feb 11 15:26:20.323 INFO main: AddLocal(tweustb4j6o3u5x7.onion:8233,4) +... +Feb 11 15:26:47.565 INFO main: ProcessMessages: advertizing address tweustb4j6o3u5x7.onion:8233 +``` + +4. Connect to a single Zcash Onion server +----------------------------------------- + +This invocation will start zcashd and connect via Tor to a single zcashd onion +server. + +Launch zcashd as follows: + +```bash +$ zcashd -onion=127.0.0.1:9050 -connect=ynizm2wpla6ec22q.onion +``` + +- `-onion=ip:port`: Use SOCKS5 proxy to reach peers via Tor hidden services. + This must match the port IP and port on which your Tor listener is + configured. +- `-connect=`: Connect only to the specified node(s); `-noconnect` + or `-connect=0` alone to disable automatic connections - ./zcashd -onion=127.0.0.1:9050 -connect=zctestseie6wxgio.onion Now use zcash-cli to verify there is only a single peer connection. - zcash-cli getpeerinfo +```bash +$ zcash-cli getpeerinfo +``` + +```javascript +[ + { + "id": 1, + "addr": "ynizm2wpla6ec22q.onion", + ... + "version": 170013, + "subver": "/MagicBean:4.2.0/", + "inbound": false, + ... + } +] +``` + +4. Connect to multiple Zcash Onion servers +------------------------------------------ + +This invocation will start zcashd, skip DNS seeding, connect via Tor to a +multiple zcashd onion servers, and also advertise your Onion server to other +Tor capable Zcash nodes. + +Launch zcashd as follows: + +```bash +$ export MY_ONION_HOSTNAME=`sudo cat /var/lib/tor/zcash_hidden_service_v2/hostname` +$ zcashd -listen -onion=127.0.0.1:9050 -addnode=ynizm2wpla6ec22q.onion -dnsseed=0 -onlynet=onion -externalip=$MY_ONION_HOSTNAME -bind=127.0.0.1 +``` + +zcashd flags used: + +- `-onion=ip:port`: Use SOCKS5 proxy to reach peers via Tor hidden services. + This must match the port IP and port on which your Tor listener is + configured. +- `-addnode=`: Add a node to connect to and attempt to keep the + connection open +- `-externalip=`: sets the publicly routable address that zcashd will + advertise to other zcash nodes. This can be an IPv4, IPv6 or .onion address. + Onion addresses are given preference for advertising and connections. Onionv3 + addresses are [not yet supported](https://github.com/zcash/zcash/issues/3051). +- `-listen`: Enable listening for incoming connections with this flag; + listening is off by default, but is needed in order for Tor to connect to + zcashd. +- `-bind=`: Bind (only) to this IP. Will bind to all interfaces by default + if `listen=1` and `bind` is not set. +- `-onlynet=`: Only connect to nodes in network `` (ipv4, ipv6 or + onion) - [ - { - "id" : 1, - "addr" : "zctestseie6wxgio.onion:18233", - ... - "version" : 170002, - "subver" : "/MagicBean:1.0.0/", - ... - } - ] -To connect to multiple Tor nodes, use: - ./zcashd -onion=127.0.0.1:9050 -addnode=zctestseie6wxgio.onion -dnsseed=0 -onlynet=onion