setgid sticky bit not working

Question

I have yet another frustrating problem. I have a group of users belonging to the "testing" group. I have a folder located at /var/log/projects with the setgid bit set. This is so any new files or folders that get created in /projects will always retain the group ownership of "testing".

[root@system log]# ll | grep projects
drwxr-s---. 4 root   testing     4096 Jun 10 19:36 projects

When I touch a file or create a folder in that directory they inherit the correct perms and ownership.

[root@system log]# touch /var/log/projects/testfile
[root@system log]# ll /var/log/projects/
total 4
-rw-r--r--. 1 root testing    0 Jun 10 19:49 testfile

And when I create a new folder its works as expected.

[root@system projects]# mkdir folder1
[root@system projects]# ll
total 8
drwxr-sr-x. 2 root testing 4096 Jun 10 19:52 folder1
-rw-r--r--. 1 root testing    0 Jun 10 19:49 testfile

So far so good. However I am using this folder for remote syslogs from other systems. When I start the rsyslogd service, any folders of files created by that process inherit the ownership of root:root.

drwx--S---. 2 root root 4096 Jun 10 19:44 remotehost

I was under the impression that the purpose of the setgid bit was for my use case. Can anyone tell me what I am doing wrong or how I can fix this so that any folders/files created by the rsyslogd process have the group ownership of "testing"? This is on a RHEL 6 server.

Answer 1

The method you made would work with programs that don't specifically manage their output permissions and ownership, but rsyslogd does.

Rsyslogd's output module documentation page shows that you can use the fileGroup [groupName] configuration directive to set the default value for the output file's group.

Answer 2

Since rsyslog ignores setgid sticky bits I was able to correct the issue by using the following directives in my rsyslogd.conf custom template config:

$template TmplAuth, "/var/log/projects/%FROMHOST-IP%/%PROGRAMNAME%.log"
$template TmplMsg, "/var/log/projects/%FROMHOST-IP%/%PROGRAMNAME%.log"
$umask 0000
$DirCreateMode 0750
$FileCreateMode 0640
$FileGroup testing
$DirGroup testing
authpriv.*   ?TmplAuth
*.info,mail.none,authpriv.none,cron.none   ?TmplMsg

NOTE $DirCreateMode and $FileCreateMode will not work until you override the default umask with the $umask 0000 directive.