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<p>I struggled for quite some time to get opensips-cli working on
Ubuntu 20.04 LTS.</p>
<p>It seems that there are now some security protections within the
Linux kernel (<code>fs.protected_fifos) </code>against users
other then the original creator from writing to fifo files in
/tmp.</p>
<p><a moz-do-not-send="true"
href="https://unix.stackexchange.com/questions/503111/group-permissions-for-root-not-working-in-tmp">https://unix.stackexchange.com/questions/503111/group-permissions-for-root-not-working-in-tmp</a></p>
<p>I eventually got opensips-cli working by moving the opensips_fifo
into /var/run/opensip/ instead of /tmp and then setting up an
opensips-cli.cnf file that pointed opensips-cli to the new fifo
path.</p>
<p>I don't fully undertand the reasons for protecting fifos in this
manner but I'm guessing that the intent is to prevent something
other then the intended application from creating the fifo first
and then snooping in to any data sent by client applications.
Although the risk for something like opensips-cli is probably
minimal, I can see how this may present a security risk for other
applications.<br>
</p>
<p>This calls into question whether it is sensible to continue
creating the opensips_fifo within /tmp by default? Perhaps, for
future versions, the default should be in a directory owned by the
opensips user (rather than one with the sticky bit set)?<br>
</p>
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