Hartmut Holzgraefe added a comment - 1 week ago > As far as I know, the implementations can't be 100% the same due to licensing reasons unless we rewrite the one in the MariaDB server with 100% new code that's owned by MariaDB. As far as I can tell both `auth_pam` v1, and especially the v2 `auth_pam_tool` external helper process, source files clearly have MariaDB copyright headers only, no mention of MySQL or Oracle anywhere in server/plugin/auth_pam/ at all > As Markus said, the REST-API pam implementation calls the same functions as the sql authenticator. I was referring to "I see that there is PAM sandboxing process support now in 23.08, but only for listeners, not for the REST APIs admin_pam_readwrite_service" when claiming different implementations. Yes, the same PAM library functions are called in the end, but that was not what I was referring to > I tested this with MaxScale and it worked correctly. I can still reproduce that maxscale REST api PAM authentication behaves differently than the servers client authentication using the same PAM service. Client connecting to MariaDB server directly, with user in correct group: noformat $ mysql --host=mariadb --port=3306 --user=unix_mysql --password=secret test Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 39 Server version: 10.6.21-MariaDB-ubu2004 mariadb.org binary distribution ... -------- Mar 5 23:10:45 ubuntu-focal auth_pam_tool: pam_succeed_if(mariadb_unix:auth): 'user' resolves to 'unix_mysql' Mar 5 23:10:45 ubuntu-focal auth_pam_tool: pam_succeed_if(mariadb_unix:auth): requirement "user ingroup mysql" was met by user "unix_mysql" noformat Client connecting to the server directly. noformat $ mysql --host=mariadb --port=3306 --user=unix_user --password=secret test ERROR 1045 (28000): Access denied for user 'unix_user'@'mariadb' (using password: NO) Mar 5 23:21:03 ubuntu-focal auth_pam_tool: pam_succeed_if(mariadb_unix:auth): 'user' resolves to 'unix_user' Mar 5 23:21:03 ubuntu-focal auth_pam_tool: pam_succeed_if(mariadb_unix:auth): requirement "user ingroup mysql" not met by user "unix_user" noformat Doing the same via maxscale both logins seem to work at first, but it turns out that no actual client session exists as maxscale logs noformat 2025-03-05 23:22:43 info : (2) [readwritesplit] (Read-Write-Service); Server 'server1' failed: Authentication to 'server1' failed: 1045, #28000: Access denied for user 'unix_user'@'localhost' (using password: NO) (server1, session=2, conn_id=72, idle=0s) 2025-03-05 23:22:43 error : (2) (Read-Write-Service); All backends are now permanently unusable, closing session. { Name: server1 Open: Broken Status: Master, Running } Error from 'server1': Authentication to 'server1' failed: 1045, #28000: Access denied for user 'unix_user'@'localhost' (using password: NO) (server1, session=2, conn_id=72, idle=0s) noformat and any attempt to run actual queries ends in ERROR 2006 (HY000): Server has gone away authenticator=PAMAuth and authenticator=PAMBackendAuth had been added to the listener and server sections. Now turning to maxctrl : Both the user in the correct group and the one not being a member of the required group can connect: maxctrl --user=unix_mysql --password=secret list servers and maxctrl --user=unix_user --password=secret list servers both work. And all the log output I'm getting is 2025-03-05 23:27:58 info : Accept authentication from 'unix_user', using password. Request: /v1/servers in the maxscale log, in /var/log/auth.log there's nothing in either case. Only when using a nonexisting user, or a wrong password, access fails and there is Mar 5 23:30:26 ubuntu-focal maxscale [2420] : pam_unix(mariadb_unix:auth): authentication failure; logname= uid=996 euid=996 tty= ruser= rhost= user=unix_user in the auth.log for the attempt with wrong password, and Mar 5 23:30:18 ubuntu-focal maxscale[2420]: pam_unix(mariadb_unix:auth): check pass; user unknown Mar 5 23:30:18 ubuntu-focal maxscale[2420]: pam_unix(mariadb_unix:auth): authentication failure; logname= uid=996 euid=996 tty= ruser= rhost= Mar 5 23:30:19 ubuntu-focal maxscale[2420]: pam_unix(mariadb_unix:auth): check pass; user unknown Mar 5 23:30:19 ubuntu-focal maxscale[2420]: pam_unix(mariadb_unix:auth): authentication failure; logname= uid=996 euid=996 tty= ruser= rhost= (yes, twice) for the attempt with an unknown user. So why is there no debug/audit log info in auth.log coming from maxscale, just error output, while the server shows debug/audit output just fine; and why does the server correctly fail on wrong group membership, but when PAM checks are initiated by maxscale it looks as if the pam_succeed_if ... ingroup ... is apparently ignored completely? I even tried with both the old and new server plugins for PAM to see whether this maybe only works with the new extra `auth_pam_tool` process approach, but found that it works fine the same on the server side with both versions. Versions I'm currently testing with: MariaDB 10.6.21 Maxscale 24.02.4 OS: Ubuntu 20.04.6 LTS