AVC generated from virtual terminal switch ('Ctl-Alt-F1/Ctl-Alt-F7')

[Daniel J Walsh]

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Tom London wrote:
> Running Rawhide, targeted enforcing.
> 
> Booting into gdm/gnome, entering 'Ctl-Alt-F1' and logging in as the
> same user generates the following audit messages:
> 
> type=USER_AUTH msg=audit(1199979217.226:28): user pid=2602 uid=0
> auid=4294967295 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='op=PAM:authentication acct=tbl exe="/bin/login" (hostname=?,
> addr=?, terminal=tty1 res=failed)'
> type=USER_LOGIN msg=audit(1199979217.266:29): user pid=2602 uid=0
> auid=4294967295 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='uid=500: exe="/bin/login" (hostname=?, addr=?, terminal=tty1
> res=failed)'
> type=USER_AUTH msg=audit(1199979226.383:30): user pid=2602 uid=0
> auid=4294967295 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='op=PAM:authentication acct=tbl exe="/bin/login" (hostname=?,
> addr=?, terminal=tty1 res=failed)'
> type=USER_LOGIN msg=audit(1199979226.384:31): user pid=2602 uid=0
> auid=4294967295 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='uid=500: exe="/bin/login" (hostname=?, addr=?, terminal=tty1
> res=failed)'
> type=USER_AUTH msg=audit(1199979234.098:32): user pid=2602 uid=0
> auid=4294967295 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='op=PAM:authentication acct=tbl exe="/bin/login" (hostname=?,
> addr=?, terminal=tty1 res=success)'
> type=USER_ACCT msg=audit(1199979234.106:33): user pid=2602 uid=0
> auid=4294967295 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='op=PAM:accounting acct=tbl exe="/bin/login" (hostname=?, addr=?,
> terminal=tty1 res=success)'
> type=LOGIN msg=audit(1199979234.108:34): login pid=2602 uid=0 old
> auid=4294967295 new auid=500
> type=USER_ROLE_CHANGE msg=audit(1199979234.130:35): user pid=2602
> uid=0 auid=500 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='pam: default-context=unconfined_u:unconfined_r:unconfined_t:s0
> selected-context=unconfined_u:unconfined_r:unconfined_t:s0:
> exe="/bin/login" (hostname=?, addr=?, terminal=tty1 res=success)'
> type=AVC msg=audit(1199979234.132:36): avc:  denied  { link } for
> pid=2602 comm="login"
> scontext=system_u:system_r:local_login_t:s0-s0:c0.c1023
> tcontext=system_u:system_r:xdm_t:s0-s0:c0.c1023 tclass=key
> type=SYSCALL msg=audit(1199979234.132:36): arch=40000003 syscall=288
> success=no exit=-13 a0=8 a1=fffffffc a2=fffffffd a3=1f4 items=0 ppid=1
> pid=2602 auid=500 uid=500 gid=500 euid=0 suid=0 fsuid=0 egid=0 sgid=0
> fsgid=0 tty=tty1 comm="login" exe="/bin/login"
> subj=system_u:system_r:local_login_t:s0-s0:c0.c1023 key=(null)
> type=USER_START msg=audit(1199979234.142:37): user pid=2602 uid=0
> auid=500 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='op=PAM:session_open acct=tbl exe="/bin/login" (hostname=?,
> addr=?, terminal=tty1 res=success)'
> type=CRED_ACQ msg=audit(1199979234.142:38): user pid=2602 uid=0
> auid=500 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='op=PAM:setcred acct=tbl exe="/bin/login" (hostname=?, addr=?,
> terminal=tty1 res=success)'
> type=USER_LOGIN msg=audit(1199979234.145:39): user pid=2602 uid=0
> auid=500 subj=system_u:system_r:local_login_t:s0-s0:c0.c1023
> msg='uid=500: exe="/bin/login" (hostname=?, addr=?, terminal=tty1
> res=success)'
> 
> Putting system into permissive mode and retrying appears to generate
> no new AVCs.
> 
> Does
> 
> #============= local_login_t ==============
> allow local_login_t xdm_t:key link;
> 
> make sense?
> 
> tom

This is caused by a bad gdm pam file.  You pam file should look
something like.

#%PAM-1.0
auth     [success=done ignore=ignore default=bad] pam_selinux_permit.so
auth       required    pam_env.so
auth       substack    system-auth
auth       optional    pam_gnome_keyring.so
account    required    pam_nologin.so
account    include     system-auth
password   include     system-auth
session    required    pam_selinux.so close
session    required    pam_loginuid.so
session    optional    pam_console.so
session    required    pam_selinux.so open
session    optional    pam_keyinit.so force revoke
session    required    pam_namespace.so
session    optional    pam_gnome_keyring.so auto_start
session    include     system-auth

pam_keyinit.so has to happen after pam_selinux.  This will create a
keyring labeled unconfined_t or xguest_t which other domains would have
access to.   A keyring labeled after a login program makes no sense.

I just updated gdm in rawhide to have this pam file.
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