LP #1521578: mysql client is not authenticating OS user with PAM plugin

This is not a bug. MySQL command line client searches for the directory where client plugins are installed. Value of the server variable plugin_dir is not relevant here. Unfortunately, client cannot default to the correct local directory, because client, unlike the server, does not have option --basedir. Therefore it simply does not know where to find the plugin. This behavior is documented at https://dev.mysql.com/doc/refman/8.0/en/mysql-command-options.html#option_mysql_plugin-dir

This bug persists to this day, I've just tested it from Percona Server 5.7.31 installed from a tarball, then loading the Percona authentication plugin:

and then creating a database user set to use PAM authentication:

... and nothing else. Then I tried to connect and I got the same error:

It does look like the library is statically linked there. I did the test and copied the dialog.so library, which is used by the PAM plugin, to the aforementioned directory; MySQL no longer complains about the file not being there, but of a missing dependency now:

 From a previous comment in this thread:

Looks like you are using binary tarball. Since tarball can be extracted anywhere, where do you expect mysql to look for plugins? There is a --plugin-dir option to specify plugin directory.

plugin_dir is correctly set:

and the target library can be found there:

**Comment from Launchpad by: Launchpad Janitor on: 13-02-2016 04:17:27

[Expired for Percona Server 5.6 because there has been no activity for 60 days.]

**Comment from Launchpad by: Launchpad Janitor on: 13-02-2016 04:17:26

[Expired for Percona Server 5.5 because there has been no activity for 60 days.]

**Comment from Launchpad by: Sergei Glushchenko on: 06-12-2015 02:09:56

Looks like you are using binary tarball. Since tarball can be extracted anywhere, where do you expect mysql to look for plugins? There is a --plugin-dir option to specify plugin directory.