opensnitch/README.md

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  <img alt="opensnitch" src="https://raw.githubusercontent.com/evilsocket/opensnitch/master/ui/res/icon.png" height="160" />
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    <a href="https://github.com/evilsocket/opensnitch/releases/latest"><img alt="Release" src="https://img.shields.io/github/release/evilsocket/opensnitch.svg?style=flat-square"></a>
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**OpenSnitch** is a GNU/Linux port of the Little Snitch application firewall. 

<p align="center">
  <img src="https://raw.githubusercontent.com/evilsocket/opensnitch/master/screenshot.png" alt="OpenSnitch"/>
</p>

### Daemon

The `daemon` is implemented in Go and needs to run as root in order to interact with the Netfilter packet queue, edit 
iptables rules and so on, in order to compile it you will need to install the `protobuf-compiler`, `libpcap-dev` and `libnetfilter-queue-dev`
packages on your system, then just:

    cd daemon
    go build .

### Qt5 UI

The user interface is a python script running as a `gRPC` server on a unix socket, to order to install its dependencies:

    cd ui
    pip install -r requirements.txt

You will also need to install the package `python-pyqt5` for your system (if anyone finds a way to make this work from 
the `requirements.txt` file feel free to send a PR).

### Running

First, you need to decide in which folder opensnitch rules will be saved, it is suggested that you just:

    mkdir -p ~/.opensnitch/rules

Now run the daemon:

    sudo /path/to/daemon -ui-socket unix:///tmp/osui.sock -rules-path ~/.opensnitch/rules

And the UI service as your user:

    python /path/to/ui/main.py --socket unix:///tmp/osui.sock

You can also use `--socket "[::]:50051"` to have the UI use TCP instead of a unix socket and run the daemon on another
computer with `-ui-socket "x.x.x.x:50051"` (where `x.x.x.x` is the IP of the computer running the UI service).

### Rules

Rules are stored as JSON files inside the `-rule-path` folder, in the simplest cast a rule looks like this:

```json
{
   "created": "2018-04-07T14:13:27.903996051+02:00",
   "updated": "2018-04-07T14:13:27.904060088+02:00",
   "name": "deny-simple-www-google-analytics-l-google-com",
   "enabled": true,
   "action": "deny",
   "duration": "always",
   "operator": {
     "type": "simple",
     "operand": "dest.host",
     "data": "www-google-analytics.l.google.com"
   }
}
```

| Field            | Description   |
| -----------------|---------------|
| created          | UTC date and time of creation. |
| update           | UTC date and time of the last update. |
| name             | The name of the rule. |
| enabled          | Use to temporarily disable and enable rules without moving their files. |
| action           | Can be `deny` or `allow`. |
| duration         | For rules persisting on disk, this value is default to `always`. |
| operator.type    | Can be `simple`, in which case a simple `==` comparision will be performed, or `regexp` if the `data` field is a regular expression to match. |
| operator.operand | What element of the connection to compare, can be one of: `true` (will always match), `process.path` (the path of the executable), `user.id`, `dest.ip`, `dest.host` or `dest.port`. |
| operator.data    | The data to compare the `operand` to, can be a regular expression if `type` is `regexp`. |

An example with a regular expression:

```json
{
   "created": "2018-04-07T14:13:27.903996051+02:00",
   "updated": "2018-04-07T14:13:27.904060088+02:00",
   "name": "deny-any-google-analytics",
   "enabled": true,
   "action": "deny",
   "duration": "always",
   "operator": {
     "type": "regexp",
     "operand": "dest.host",
     "data": "(?i).*analytics.*\\.google\\.com"
   }
}
```

An example whitelisting a whole process:

```json
{
   "created": "2018-04-07T15:00:48.156737519+02:00",
   "updated": "2018-04-07T15:00:48.156772601+02:00",
   "name": "allow-simple-opt-google-chrome-chrome",
   "enabled": true,
   "action": "allow",
   "duration": "always",
   "operator": {
     "type": "simple",
     "operand": "process.path",
     "data": "/opt/google/chrome/chrome"
   }
 }
```

### FAQ

##### Why Qt and not GTK?

I tried, but for very fast updates it failed bad on my configuration (failed bad = SIGSEGV), moreover I find Qt5 layout system superior and easier to use.

##### Why gRPC and not DBUS?

The UI service is able to use a TCP listener instead of a UNIX socket, that means the UI service itself can be executed on any 
operating system, while receiving messages from a single local daemon instance or multiple instances from remote computers in the network,
therefore DBUS would have made the protocol and logic uselessly GNU/Linux specific.