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Tasklist

FS#58877 - Su command say: Error in service module after update with group configuration

Attached to Project: Arch Linux
Opened by Martin Strympl (sfence) - Tuesday, 05 June 2018, 14:45 GMT
Last edited by Doug Newgard (Scimmia) - Thursday, 07 June 2018, 15:19 GMT
Task Type Bug Report
Category Packages: Extra
Status Closed
Assigned To No-one
Architecture x86_64
Severity Low
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

When I use "su username" command and enter password, su say "su: Error in service module".

I have recognized that it depend on /etc/pam.d/su configuration file. When I comment line
"auth required pam_wheel.so group=_access_su"
su starts to work withou error message.
I have tried change line to "auth required pam_wheel.so group=host" and su fail with same error.

su --version say su from util-linux 2.32

"man pam_wheel.so" say, that group parameter should be still supported with group name...
This task depends upon

Closed by  Doug Newgard (Scimmia)
Thursday, 07 June 2018, 15:19 GMT
Reason for closing:  Not a bug
Additional comments about closing:  Config issue
Comment by loqs (loqs) - Tuesday, 05 June 2018, 20:05 GMT
https://github.com/linux-pam/linux-pam/blob/Linux-PAM-1.3.0/modules/pam_wheel/pam_wheel.c#L138

From the pam_wheel man page
...
use_uid
The check for wheel membership will be done against the current uid
instead of the original one (useful when jumping with su from one
account to another for example).
...
RETURN VALUES
PAM_SERVICE_ERR
Cannot determine the user name.
Comment by Martin Strympl (sfence) - Wednesday, 06 June 2018, 15:53 GMT
When I update ocnfiguration line to "auth required pam_wheel.so use_uid group=_access_su", it works...

This some new feature? Becouse I was running with configuration "auth required pam_wheel.so group=_access_su" longer then one year witou problems.
But when I do pacman -Syu on 04 June 2018, it stops to work...
Comment by loqs (loqs) - Wednesday, 06 June 2018, 17:50 GMT
Possibly https://www.archlinux.org/news/glibc-227-2-and-pam-130-2-may-require-manual-intervention/ I do not know what packages the pacman update you referenced contained for your system.
The relevant code in pam_wheel has not been changed in over ten years.
Comment by Martin Strympl (sfence) - Wednesday, 06 June 2018, 19:43 GMT
It is interesting....
In attachmet is part of my pacman log... Where is see what pacman upgraded... after this upgrade, su stops to work with configuration file including line "auth required pam_wheel.so group=_access_su".

But problem is solved, that, if you not interested in looking for reasons of unexpected behaviours, this issue can be closed....
Comment by loqs (loqs) - Wednesday, 06 June 2018, 20:26 GMT
pam, pam_base, util-linux and glibc were not in the update so I have no idea why the issue started then sorry.

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