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I need to restrict ssh access to hosts based on the user's LDAP group membership. I want to do this using sssd's ldap_access_filter feature. Here's my sssd.conf file:

[sssd]
config_file_version = 2
services = nss, pam
domains = default

[nss]
filter_users = root,ldap,named,avahi,haldaemon,dbus,radiusd,news,nscd

[pam]

[domain/default]
debug_level = 5
ldap_tls_reqcert = never
auth_provider = ldap
access_provider = ldap
ldap_schema = rfc2307bis
ldap_search_base = dc=edurp,dc=com
ldap_group_member = uniquemember
#id_provider = ldap
ldap_id_use_start_tls = False
chpass_provider = ldap
ldap_uri = ldaps://ldap0.la01.edurp.com/,ldaps://ldap1.la01.edurp.com/
ldap_chpass_uri = ldaps://ldap0.edurp.com/
cache_credentials = True
ldap_tls_cacertdir = /etc/openldap/cacerts
entry_cache_timeout = 600
ldap_network_timeout = 3
ldap_access_filter = (&(object)(object))
krb5_realm = EXAMPLE.COM
krb5_kdcip = kerberos.example.com
ldap_access_filter = (|(memberOf=cn=datateam,ou=group,dc=edurp,dc=com)(memberOf=cn=ctmtest,ou=group,dc=edurp,d    c=com)(memberOf=cn=syseng,ou=group,dc=edurp,dc=com))

My nsswitch.conf file looks like this:

passwd:     files sss
shadow:     files sss
passwd_compat: sss
shadow_compat: sss
group:      files sss
hosts:      files dns
bootparams: nisplus [NOTFOUND=return] files
ethers:     files
netmasks:   files
networks:   files
protocols:  files
rpc:        files
services:   files sss
netgroup:   sss files
publickey:  nisplus
automount:  files ldap
aliases:    files nisplus

So the error messages I see in /var/log/sssd/

(Wed Jun 25 12:25:36 2014) [sssd[be[default]]] [be_pam_handler_callback] (0x0100): Backend returned: (0, 6, <NULL>) [Success]
(Wed Jun 25 12:25:36 2014) [sssd[be[default]]] [be_pam_handler_callback] (0x0100): Sending result [6][default]
(Wed Jun 25 12:25:36 2014) [sssd[be[default]]] [be_pam_handler_callback] (0x0100): Sent result [6][default]
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [be_get_account_info] (0x0100): Got request for [3][1][name=bobdog]
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [acctinfo_callback] (0x0100): Request processed. Returned 0,0,Success
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [be_pam_handler] (0x0100): Got request with the following data
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): command: PAM_ACCT_MGMT
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): domain: default
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): user: bobdog
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): service: sshd
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): tty: ssh
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): ruser:
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): rhost: 10.65.6.65
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): authtok type: 0
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): authtok size: 0
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): newauthtok type: 0
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): newauthtok size: 0
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): priv: 1
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [pam_print_data] (0x0100): cli_pid: 48404
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [sdap_access_filter_get_access_done] (0x0100): User [bobdog] was not found with the specified filter. Denying access.
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [be_pam_handler_callback] (0x0100): Backend returned: (0, 6, <NULL>) [Success]
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [be_pam_handler_callback] (0x0100): Sending result [6][default]
(Wed Jun 25 12:29:37 2014) [sssd[be[default]]] [be_pam_handler_callback] (0x0100): Sent result [6][default]

And in /var/log/secure I see:

Jun 25 12:29:37 vmtest0 sshd[48404]: pam_sss(sshd:account): Access denied for user bobdog: 6 (Permission denied)
Jun 25 12:29:37 vmtest0 sshd[48405]: fatal: Access denied for user bobdog by PAM account configuration

I'm being made to use Oracle 6.5 Linux and openldap on the client machines for this project. The ldap servers run dsee7.

Thanks for any advice.

share|improve this question
    
My user is definitely a member of the LDAP group syseng, and was able to ssh in to the machine before I started messing with sssd.conf. I know I need to restart sssd after I change anything in sssd.conf. –  mr.zog Jun 25 at 16:43

1 Answer 1

Without an id_provider sssd cannot perform any of its nsswitch roles. All sss user and group resolution will fail. You can see this with getent passwd bobdog.


I notice you have two different ldap_access_filter. Though the first one seems bad, but it's last value wins, so that's more of a tidiness issue.

ldap_access_filter = (&(object)(object))
ldap_access_filter = (|(memberOf=cn=datateam,ou=group,dc=edurp,dc=com)(memberOf=cn=ctmtest,ou=group,dc=edurp,dc=com)(memberOf=cn=syseng,ou=group,dc=edurp,dc=com))

Additionally, I don't know if dsee7 supports memberof, though I suspect it does. It is worth double checking. memberof is usually an operational attribute, so you have to ask for it explicitly. ldapsearch -H ldaps://ldap0.la01.edurp.com/ -b dc=edurp,dc=com uid=bobdog memberof.


It's generally better to use SRV RRs than explicit hosts. You're already relying on DNS for name resolution.


If you have a kerberos KDC, you might want to use krb5 as your auth_provider and use sshd's AllowGroups instead to restrict access. GSSAPI is handy at times.

AllowGroups
This keyword can be followed by a list of group name patterns, separated by spaces. If specified, login is allowed only for users whose primary group or supplementary group list matches one of the patterns. Only group names are valid; a numerical group ID is not recognized. By default, login is allowed for all groups. The allow/deny directives are processed in the following order: DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups.
See PATTERNS in ssh_config(5) for more information on patterns.

share|improve this answer
    
We are using hbac rules rather than ldap_access_filter to govern access to hosts. It makes it easier to manage than having to update sssd.conf anytime your access policy changes. Also allows you to filter access on specific services. –  lsd Jun 25 at 17:30
    
Do I need to run an IPA server to use HBAC rules? Seems like I do. Just checking. –  mr.zog Jun 25 at 17:43
    
@84104 I do have a line "id_provider = ldap" in my sssd.conf –  mr.zog Jun 25 at 17:52
    
@mr.zog Then update your question accordingly. The config you provided had it commented out. –  84104 Jun 25 at 18:14
    
Oh sorry. I've been changing it a lot. –  mr.zog Jun 25 at 19:10

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