convention on listen port local or all network interfaces etc.
A convention on listen port local or all network interfaces etc. would be desirable.
At the moment it looks like there is no convention for where server applications are configured to listen by default, on localhost vs. all interfaces. Looks like deciding that is up to the upstream author of the software as well as the packager. Then it's up to the system administrator to decide on where the server application should listen. There is no great place for derivatives to globally modify this setting.
Usually applications using Tor ephemeral hidden services such as ricochet-im, onionshare, ZeroNet, unMessage listen on localhost only.
Whonix is a Debian derivative with focus on anonymity, privacy and security. To oversimplify it, we preconfigure Debian with these goals in mind.
Due to Whonix's workstation, gateway split design, applications using Tor ephemeral hidden services need to listen on the workstation's external interface rather than on the workstation's localhost.
A global configuration file such as `/etc/ricochet-im.conf` works for system administrators, but not for derivatives.
Why is a config folder `/etc/ricochet-im.d` strongly preferred over a config file `/etc/ricochet-im.conf`? When a config file such as `/etc/ricochet-im.conf` is owned by one package `ricochet-im`, it cannot be owned by another package. If another package was to modify it using `sed` or so, then dpkg would regard that file as user modified. The problem is, next time that config file is changed by upstream, this throws an interactive dpkg conflict resolution dialog at the user, which is a usability bug. (example [x]) `sed` style config modifications are a Debian policy violation as well.
So far we at Whonix had discussions with ricochet-im, onionshare, ZeroNet and unMessage. They are all interested to make their applications compatible with Whonix. However, asking each individual project to `/etc/application-specific.d` folder where Whonix then could drop a `/etc/application-specific.d/30_whonix.conf` that says `listen=10.152.152.10` is a lot duplicate effort and not that desirable for these applications because they have not yet any need for `/etc/application-specific.d/`.
Having these applications auto detect Whonix also does not seem like great solution. Seems unsafe. If the auto detection code kicks in as a false positive, users would be at risk. Since it's Whonix specific and general solutions reusable by anyone are to be preferred. At least that is my interpretation of *nix philosophy.
May the following convention be suggested.
* Parse in lexical order.
** Similar to how systemd would parse these folders. I.e. for example start with parsing `/usr/lib/server-config.d/30_default.conf`, followed by `/usr/lib/server-config.d/31_other.conf`, followed by `/etc/server-config.d/30_user.conf`, followed by `/etc/server-config.d/40_user.conf` and so forth.
* The pseudo code in shell / bash:
for file_name in /usr/lib/server-config.d/*.conf ; do
for file_name in /etc/server-config.d/*.conf ; do
for file_name in /home/.config/server-config.d/*.conf ; do
for item in $file_list ; do
* config options:
# lines starting with # are ignored
# global fallback setting for all listeners
# web interfaces
# listen incoming IP
# optional application specific listen port
Would mean listen on `0.0.0.0` as well as on `127.0.0.1`.
This disable listeners by previous lower priority configuration files, one could use `listen_ip=`. For example:
Would result in listening on `127.0.0.1` only. This is similar to how systemd parses systemd unit files.
To prevent different applications to parse the configuration differently, to avoid unexpected results, it would be useful to have a python library and command line tool to query it.
Any questions? Any suggestions? What do you think?
* improve draft
* send to debian-devel mailing list
* discuss on debian-devel