Ubuntu Manpage: oracle - server for the SPHINX password manager

NAME

       oracle - server for the SPHINX password manager

SYNOPSIS

       oracle

DESCRIPTION

       The  SPHINX protocol only makes sense if the server (called oracle) is somewhere else than where you type
       your password, pwdsphinx comes with a server implemented in python3 which you can host off-site from your
       usual desktop/smartphone.

       The server can be started simply by running oracle it does not take any parameters.

CONFIGURATION

The server can be configured by any of the following files:

• /etc/sphinx/config

• ~/.sphinxrc

• ~/.config/sphinx/config

• ./sphinx.cfg

Files are parsed in this order, this means global settings can be overridden by per-user and per-directo‐
ry settings.

The server can be configured by changing the variables in the [server] section of the config file.

The address is the IP address on which the server is listening, default is localhost - you might want to
change that.

The port where the server is listening is by default 2355. Another recommended values is to use port 433
which is allowed by most firewalls while 2355 is not.

ssl_key and ssl_cert must be specified, they point at a traditional TLS certificate and secret key file.
It is recommended to not use self-signed certs, but to use certs that signed by CAs that are recognised
widely by browsers and other TLS clients.

datadir specifies the data directory where all the device “secrets” are stored, this defaults to “data/”
in the current directory. You might want to back up this directory from time to time to an encrypted
medium.

verbose enables logging to standard output.

timeout sets the timeout for any connection the server keeps open.

max_kids sets the number maximum requests handled in parallel. The timeout config variable makes sure
that all handlers are recycled in predictable time.

rl_decay specifies the number of seconds after which a ratelimit level decays to an easier difficulty.

rl_threshold increase the difficulty of ratelimit puzzles if not decaying.

rl_gracetime gracetime in seconds added to the expcted time to solve a rate-limiting puzzle.

SECURITY CONSIDERATIONS

       The configuration values max_kids and timeout can be used to tune how many requests are served in  paral‐
       lel and how long each request is allowed to take before it gets killed.  An attacker might be able to run
       a denial-of-service attack against your server, by keeping all max_kids connections “occupied”.

       Since the server does only know about failed authorizations for management operations, but not about cor‐
       rectness of master passwords for get requests, there is no way to mitigate master password bruteforce at‐
       tempts  aside  from ratelimiting.  By tuning the configuration variables starting with rl_ it is possible
       to configure this.  If you have clients that have less than 1G RAM, it might be possible to increase  the
       difficulty  to  the  maximum level where those devices will not be able to solve the ratelimting puzzles.
       Rate-limiting in general should not be noticable, only if dozens of get requests are served to  the  same
       record.  At the highest level the solution should take about 20-40 seconds (depending on your cpu).

REPORTING BUGS

       https://github.com/stef/pwdsphinx/issues/

AUTHOR

       Written by Stefan Marsiske.

COPYRIGHT

       Copyright  ©  2023  Stefan Marsiske.  License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licens‐
       es/gpl.html>.  This is free software: you are free to change and redistribute it.  There is NO  WARRANTY,
       to the extent permitted by law.