opensnitch/wiki/Known-problems.md

**eBPF**

[cannot open kprobe_events](#cannot-open-kprobe_events): open /sys/kernel/debug/tracing/kprobe_events: permission denied

[cannot write ... kprobe_events: file exists](#kprobe_events-file-exists)

[error while loading "kprobe/(...)": invalid argument](#error-while-loading-kprobes-invalid-argument)

**General**

[KDE/Gnome/Xfce/... does not boot up](#desktop-environment-does-not-bootup)

**GUI**

[GUI crash/exception or does not show up](#gui-crash-exception-or-does-not-show-up):

* NameError: name 'unicode' is not defined
* ModuleNotFoundError: No module named 'grpc'
* TypeError: __new__() got an unexpected keyword argument ...
* Others...

[GUI crash/exception/does not show up on old distros (Ubuntu 16.04, etc)](#gui-crash-exception-does-not-show-up-on-old-distros):

[GUI not working across reboots](#gui-not-working-across-reboots)

[The GUI doesn't change to dark style theme](#the-gui-does-not-change-to-dark-style-theme)

[no icons on the GUI](#no-icons-on-the-gui)

[GUI size problems on 4k monitors](#gui-size-problems-on-4k-monitors)

[OpenSnitch icon doesn't show up on Gnome-Shell](#opensnitch-icon-does-not-show-up-on-gnome-shell)

**daemon**

[Kernel panic on >= 5.6.16 || kernel hardening incompatibilities](#kernel-panics)

[opensnitchd/daemon does not start](#opensnitchd-does-not-start):


***

### Cannot open kprobe_events

If after enabling eBPF you see the following error:

cannot open kprobe_events: open /sys/kernel/debug/tracing/kprobe_events: permission denied

you'll need to allow opensnitch in selinux or set it to permissive:

```
$ sudo journalctl -ar | grep "opensnitch.*lockdown"
Aug 19 06:18:28 localhost-live audit[2443]: AVC avc:  denied  { confidentiality } for  pid=2443 comm=opensnitchd lockdown_reason=use of tracefs scontext=system_u:system_r:unconfined_service_t:s0 tcontext=system_u:system_r:unconfined_service_t:s0 tclass=lockdown permissive=0

$ echo "Aug 19 06:18:28 localhost-live audit[2443]: AVC avc:  denied  { confidentiality } for  pid=2443 comm=opensnitchd lockdown_reason=use of tracefs scontext=system_u:system_r:unconfined_service_t:s0 tcontext=system_u:system_r:unconfined_service_t:s0 tclass=lockdown permissive=0" > opensnitch_lockdown.txt

$ sudo su
# audit2allow -M opensnitchd < opensnitch_lockdown.txt
# semanage -i opensnitchd.pp
```

You can download this generic selinux policy from here: 
https://github.com/evilsocket/opensnitch/issues/475#issuecomment-901838324

Useful links:

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security-enhanced_linux/sect-security-enhanced_linux-fixing_problems-allowing_access_audit2allow

https://danwalsh.livejournal.com/24750.html

https://learn.netdata.cloud/docs/agent/collectors/ebpf.plugin

### kprobe_events file exists

This error indicates that the network hooks are already added, you'll need to delete them manually:

```
$ sudo su
# > /sys/kernel/debug/tracing/kprobe_events
```

If it complains with "resource busy" or similar, restart the daemon.

### Error while loading kprobes: invalid argument

> eBPF Failed to load /etc/opensnitchd/opensnitch.o: error while loading "kprobe/tcp_v4_connect" (invalid argument):

This error may indicate that your kernel doesn't have [ftrace](https://www.kernel.org/doc/html/latest/trace/ftrace.html) support, which is needed for eBPF to work.

CONFIG_FTRACE should be **y** and the directory `/sys/kernel/debug/tracing/` must exist.

```
$ grep CONFIG_FTRACE /boot/config-$(uname-r)
CONFIG_FTRACE=y
```

If the output is `# CONFIG_FTRACE is not set`, your kernel is not compiled with ftrace support.

Read more: [#475](https://github.com/evilsocket/opensnitch/issues/475)

### Desktop Environment does not boot up

If after installing OpenSnitch, or after changing the Default Action to `deny`, the Desktop Environment does not show up (after restart), try:

1. setting the `DefaultAction` back to `allow`
2. adding a rule to allow system apps.

In both cases the idea is to allow certain programs needed by KDE, Gnome, etc: dirmngr, xbrlapi, host, kdeinit5. [more info #402](https://github.com/evilsocket/opensnitch/issues/402):

Save it to `/etc/opensnitchd/rules/000-allow-system-cmds.json`
```
{
  "created": "2021-04-26T09:58:03.704090244+02:00",
  "updated": "2021-04-26T09:58:03.704216578+02:00",
  "name": "000-allow-system-cmds",
  "enabled": true,
  "precedence": true,
  "action": "allow",
  "duration": "always",
  "operator": {
    "type": "regexp",
    "operand": "process.path",
    "sensitive": false,
    "data": "^(/usr/bin/host|/usr/bin/xbrlapi|/usr/bin/dirmngr)",
    "list": []
  }
}
```

You can also allow all traffic to localhost (save it to `/etc/opensnitchd/rules/000-allow-localhost.json`):
```
{
  "created": "2021-04-26T09:58:03.704090244+02:00",
  "updated": "2021-04-26T09:58:03.704216578+02:00",
  "name": "000-allow-localhost",
  "enabled": true,
  "precedence": true,
  "action": "allow",
  "duration": "always",
  "operator": {
    "type": "network",
    "operand": "dest.network",
    "sensitive": false,
    "data": "127.0.0.0/8",
    "list": []
  }
}
```

***

### GUI crash/exception or does not show up

If you have installed it by double clicking on the pkgs, using a graphical installer, try to install it from command line:

> $ sudo dpkg -i `*opensnitch*deb`; sudo apt -f install

See [issue #25](https://github.com/gustavo-iniguez-goya/opensnitch/issues/25), [issue #16](https://github.com/gustavo-iniguez-goya/opensnitch/issues/16) and [issue #32](https://github.com/gustavo-iniguez-goya/opensnitch/issues/32) for additional information.


***

You have to install `unicode_slugify` and `grpcio-tools`, usually not available in old distros. You can install them using pip:

```
pip3 install unicode_slugify
pip3 install grpcio protobuf
```

If grpcio fails to compile, you can try specifying a version: `pip3 install grpcio==1.16.1`

***

**TypeError: __new__() got an unexpected keyword argument ...**

This error means that your `python3-protobuf` is not compatible with OpenSnitch. Try uninstalling or upgrading it. If the GUI keeps failing with the same error, install protobuf using pip3: `pip3 install protobuf==3.6`

***

Check that you don't have a previous installation of opensnitch GUI in _/usr/lib/python3*/*/opensnitch/_ or _/usr/local/lib/python3*/*/opensnitch/_

If you have a previous installation remove it, and install the GUI again (you may have an installation of the original repo). 

If it doesn't work, report it describing the steps to reproduce it, and the exception or log. For example:
```
Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/opensnitch/dialogs/prompt.py", line 362, in _on_apply_clicked
    self._rule.name = slugify("%s %s %s" % (self._rule.action, self._rule.operator.type, self._rule.operator.data))
  File "/usr/lib/python3.8/site-packages/slugify.py", line 24, in slugify
    unicode(
NameError: name 'unicode' is not defined
```

--

For ArchLinux/Manjaro users this worked:
> installed was from AUR python-unicode-slugify-git r43.b696c37-1

> removed it and installed python-unicode-slugify 0.1.3-1.


***

### GUI crash/exception/does not show up on old distros

> /usr/lib/python3.5/site-packages/google/protobuf/internal/containers.py, line 333
> ... object does not support item assignment

Install needed packages from pip:
```
$ pip3 install grpcio==1.16.1
$ pip3 install unicode_slugify
$ pip3 install protobuf==3.6
```

You may need to uninstall setuptools if it keeps failing: `$ pip3 uninstall setuptools`


***

### Opensnicth GUI not working across reboots

If after installing OpenSnitch and reboot, the GUI does not show up upon login to your Desktop Environment, be sure that the following path exist in your $HOME:

`ls ~/.config/autostart/opensnitch_ui.desktop`

If it doesn't exist, create it:
```
$ mkdir -p ~/.config/autostart/
$ ln -s /usr/share/applications/opensnitch_ui.desktop ~/.config/autostart/
```

If you have installed the GUI from the repositories of a distribution, tell the maintainer of the package to create that symbolic link after installation.

see issue [#434](https://github.com/evilsocket/opensnitch/issues/434#issuecomment-859968103) for more information.

***

### The GUI does not change to dark style theme

It's usually a problem of the Desktop Environment. You can try to configure the theme by using `qt5ct`, or executing the following commands: 
```
sudo apt-get install -y qt5-style-plugins
sudo cat << EOF | sudo tee  /etc/environment
QT_QPA_PLATFORMTHEME=gtk2
EOF
```

More info: [#303](https://github.com/evilsocket/opensnitch/issues/303)

Since version v1.5.1, you can change GUI theme from the Preferences -> UI -> Theme . You'll need to install qt-material: `pip3 install qt-material`

***

### No icons on the GUI

Be sure that you have properly set the icon theme of your Window Manager. [More information](https://github.com/gustavo-iniguez-goya/opensnitch/issues/53#issuecomment-671419790)


***

### GUI size problems on 4k monitors

Some users have reported issues displaying the GUI on 4k monitors. See [#43](https://github.com/gustavo-iniguez-goya/opensnitch/issues/43) for more information.

Setting these variables may help:

```
export QT_AUTO_SCREEN_SCALE_FACTOR=0
export QT_SCREEN_SCALE_FACTORS=1 (or 1.25, 1.5, 2, ...)
```

In case of multiple displays:
`export "QT_SCREEN_SCALE_FACTORS=1;1"`


***

### OpenSnitch icon does not show up on Gnome-Shell

On Gnome-Shell >= 3.16, systray icons have been removed. You have to install the extension [gnome-shell-extension-appindicator](https://extensions.gnome.org/extension/615/appindicator-support/) to get them back.

1. Download latest version - https://github.com/ubuntu/gnome-shell-extension-appindicator/releases
2. Install it with your regular user: `gnome-extensions install gnome-shell-extension-appindicator-v33.zip`

See this comment/issue for more information: [#44](https://github.com/gustavo-iniguez-goya/opensnitch/issues/44#issuecomment-654373737)


***

### opensnitchd does not start

For all these options, 

* `Error while creating queue #0: Error binding to queue: operation not permitted.`
* `Error while enabling probe descriptor for opensnitch_exec_probe: write /sys/kernel/debug/tracing/kprobe_events: no such file or directory` (the kernel does not have support for CONFIG_FTRACE, or it's not loaded)
* `Error while creating queue #0: Error binding to queue: operation not permitted.`
* `iptables: Protocol wrong type for socket` (modules nf_defrag_ipv4, nf_conntrack_ipv4 not loaded)
* `Error opening Queue handle: protocol not supported` (nfnetlink module not loaded)
* `Could not open socket to kernel: Address family not supported by protocol (IPv6)`
* `Error while creating queue #0: Error unbinding existing q handler from AF_INET protocol` see [#323](https://github.com/evilsocket/opensnitch/issues/323) and [#204](https://github.com/evilsocket/opensnitch/issues/204#issuecomment-802932344). (probably ip_queue loaded. Unload it and try again)

be sure that you have NFQUEUE support in the kernel (=y or =m):
```
$ grep -E "(NFT|NETLINK|NFQUEUE) /boot/config-$(uname -r)"
CONFIG_NFT_QUEUE=y
CONFIG_NETFILTER_NETLINK_QUEUE=y
CONFIG_NETFILTER_XT_TARGET_NFQUEUE=y
```

and that the needed modules are loaded:
```
$ lsmod | grep -i nfqueue
xt_NFQUEUE             16384  4
x_tables               53248  20 xt_conntrack,nft_compat,xt_LOG,xt_multiport,xt_tcpudp,xt_addrtype,xt_CHECKSUM,xt_recent,xt_nat,ip6t_rt,xt_set,ip6_tables,ipt_REJECT,ip_tables,xt_limit,xt_hl,xt_MASQUERADE,ip6t_REJECT,xt_NFQUEUE,xt_mark
```

The following modules are also needed:

nf_defrag_ipv4.ko, nf_conntrack_ipv4.ko, nfnetlink.ko


***

### Kernel panics

Some users have reported kernel panics with kernel 5.6.16 ([#297](https://github.com/evilsocket/opensnitch/issues/297)) and other kernels([#41](https://github.com/gustavo-iniguez-goya/opensnitch/issues/41)). **deathtrip** found that the culprit in his/her case was a configuration of the Arch's [linux-hardened](https://www.archlinux.org/packages/extra/x86_64/linux-hardened/) kernel command line option. 

Removing the following options from the kernel booting parameters solved the issue:

`slab_nomerge, slub_debug=FZP and page_alloc.shuffle=1`

On Debian with kernel 5.7.0, remove `slub_debug=FZP` if you have it configured and try again.

**Note:** This was caused by [a bug in the libnetfilter_queue library](https://bugzilla.netfilter.org/show_bug.cgi?id=1440).