[DSE-Dev] Bug#707247: selinux-policy-default: systemd_logind_t produce AVC when trying to communicate with sshd over dbus

Michael Scherer misc at zarb.org
Wed May 8 14:35:15 UTC 2013

Package: selinux-policy-default
Version: 2:2.20110726-12
Severity: normal


Booting a system with systemd and SElinux, i have seen the following AVC :

  May  5 14:22:36 venser dbus[511]: avc:  denied  { send_msg } for msgtype=method_return dest=:1.2 spid=515 tpid=647 scontext=system_u:system_r:systemd_logind_t:s0 tcontext=system_u:system_r:sshd_t:s0-s0:c0.c1023 tclass=dbus

I have no idea of why it does try to speak to sshd over dbus. I suspect it to be due to some pam module used
there, and looking at Fedora policy, there is much more rules regarding dbus for systemd_logind_t than
on Debian, and there is indeed this one :

  allow systemd_logind_t sshd_t : dbus send_msg ; 

Without this, pam_systemd complain about :

  May 08 16:32:36 venser.ephaone.org sshd[28404]: pam_systemd(sshd:session): Failed to create session: Access denied

and I guess this prevent pam_systemd from working properly ( ie, you do not have 1 cgroups hierarchy per user,
no way to kill all the process on logout, etc, etc ).

-- System Information:
Debian Release: 7.0
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.2.0-4-amd64 (SMP w/1 CPU core)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=ANSI_X3.4-1968) (ignored: LC_ALL set to C)
Shell: /bin/sh linked to /bin/dash

Versions of packages selinux-policy-default depends on:
ii  libpam-modules   1.1.3-7.1
ii  libselinux1      2.1.9-5
ii  libsepol1        2.1.4-3
ii  policycoreutils  2.1.10-9
ii  python           2.7.3-4

Versions of packages selinux-policy-default recommends:
ii  checkpolicy  2.1.8-2
ii  setools      3.3.7-3

Versions of packages selinux-policy-default suggests:
pn  logcheck        <none>
pn  syslog-summary  <none>

-- Configuration Files:
/etc/selinux/default/modules/active/file_contexts.local [Errno 13] Permission denied: u'/etc/selinux/default/modules/active/file_contexts.local'

-- no debconf information

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