[RADIATOR] Radiator / LDAP / matching on multi-valued field

[Heikki Vatiainen]

On 15.2.2022 22.40, Dave Kitabjian wrote:

> First question: our AuthBy LDAP2 already has a PostSearchHook specified:
> 
>          PostSearchHook sub { my @hash = $_[4]->get('hash'); \
>                  my @username = $_[4]->get('sAMAccountName'); \
>                  system('/opt/radiator/radiator/goodies/inserttotp.sh', at username, at hash); \
>                  return 1 ;}
> 
> It appears that if I define two, the latter one overrides. What's the right way to configure two hooks in the same context? Is the only way to merge them into a single perl script?

You can merge them. For example, put somewhere after 'return unless 
$entry' and change $_[4] to $entry (but $_[4] would work too) for 
consistent naming.

> And the follow up question is (and forgive me that all of this plumbing isn't entirely clear to me): should the hook code from ldap-memberof-hook.pl come before inserttotp.sh since we don't want to bother to update the totp table if they're not even granted NAS access? Or the other way around, so we can track the "bad logins"??

I think there's the insertopt functionality can be placed after group 
authorisation logic. For example, just before the last 'return;' in 
ldap-memberof-hook.pl.

In the example below, it shows how to use 'Auth-Type' to trigger a 
reject. In this branch you could return directly and let the rest of the 
cases (success cases) exit via insertotp call.

For list archive and future reference, goodies/logformat.cfg has an 
example where the hooks are collected to a common module. Instead of 
having just one file with everything in a single function, module can 
contain multiple functions. In this case it may not be necessary, but if 
there is, or will be, more customisation, then this kind of 
re-arrangement can be helpful.

Thanks,
Heikki


> Thanks in advance!
> 
> Dave
> 
> -----Original Message-----
> From: radiator <radiator-bounces at lists.open.com.au> On Behalf Of Heikki Vatiainen
> Sent: Monday, February 14, 2022 8:55 AM
> To: radiator at lists.open.com.au
> Subject: Re: [RADIATOR] Radiator / LDAP / matching on multi-valued field
> 
> On 12.2.2022 0.39, Dave Kitabjian wrote:
> 
>> So, the second part of my problem is that obviously "DC=com CN=Admin
>> Access" won't match the NAS-IP-Address. What I really need is logic like:
>>
>> IF AD.memberOf(user) matches "DC=com CN=Admin Access" AND NAS-IP-Address
>> = A.B.C.D
>> THEN PASS
>> ELSE IF AD.memberOf(user) matches "DC=com CN=Regular Access" AND
>> NAS-IP-Address = W.X.Y.Z
>> THEN PASS
>> ELSE FAIL
> 
> One option is to use code to implement the authorisation logic. First,
> configure AuthBy LDAP2 to fetch 'memberOf' attributes. There's no need
> to store them in request or response, so the configuration is simply this:
> 
>       AuthAttrDef memberOf
>       PostSearchHook file:"%D/ldap-memberof-hook.pl"
> 
> The hook that processes the LDAP groups is below. Implementing flexbile
> authorisation with configuration options might be possible, for example
> how Martin shows in his email, and a hook can then cover the rest of the
> cases.
> 
> Here's ldap-memberof-hook.pl. I'll see that a copy gets added to goodies
> too. The logic is meant for tailoring for local needs.
> 
> 
> use strict;
> use warnings;
> use List::Util;
> 
> sub {
>       my $p = $_[2];     # The request
>       my $user = $_[3];  # The user trying to authenticate
>       my $entry = $_[4]; # Returned LDAP entry
>       my $rp = $_[5];    # The reply
> 
>       # Process Access-Request messages only
>       return unless $p->code() eq 'Access-Request';
> 
>       # Do nothing if the search did not return any results.
>       return unless $entry;
> 
>       # groupMembership or memberOf is typically a multivalued LDAP
> attribute for group memberships
>       my $attr = 'memberOf';
>       my $dn = $entry->dn();
>       main::log($main::LOG_DEBUG, "PostSearchHook: processing '$attr'
> values for '$dn'", $p);
> 
>       # Convert all DNs to canonical format and then fully lowercase them
>       my $admin_dn   = lc(Net::LDAP::Util::canonical_dn('CN=Demo Admin
> Access,OU=Groups,DC=dev,DC=radiatorsoftware,DC=com'));
>       my $regular_dn = lc(Net::LDAP::Util::canonical_dn('cn=DEMO Regular
> Access,ou=Groups,dc=dev,dc=radiatorsoftware,dc=com'));
>       my @ldapgroups = map { lc(Net::LDAP::Util::canonical_dn($_)) }
> $entry->get_value($attr);
> 
>       my $nas_ip = $p->get_attr('NAS-IP-Address');
> 
>       # We can now run authorisation logic based on LDAP groups, request
>       # attributes and other available information.
>       #
>       # Sample: The first NAS allows only admins, the second only
>       # regular users. Otherwise trigger failure.
>       if ($nas_ip eq '10.20.30.44' &&
>           (List::Util::first { $admin_dn eq $_ } @ldapgroups))
>       {
>           main::log($main::LOG_DEBUG, "PostSearchHook: matched LDAP group
> '$admin_dn'", $p);
>           $user->get_reply->add_attr('Reply-Message', 'You are admin');
>       }
>       elsif ($nas_ip eq '10.20.50.66' &&
>              (List::Util::first { $regular_dn eq $_ } @ldapgroups))
>       {
>           main::log($main::LOG_DEBUG, "PostSearchHook: matched LDAP group
> '$regular_dn'", $p);
>           $user->get_reply->add_attr('Reply-Message', 'You are regular');
>       }
>       else
>       {
>           # Could also use add_attr to assing a default
>           # authorization level.
>           $user->get_check->add_attr('Auth-Type', "Reject:No
> authorisation group found in LDAP for '$dn'");
>       }
> 
>       return;
> }
> 
> 
> 
> 
> --
> Heikki Vatiainen
> OSC, makers of Radiator
> Visit radiatorsoftware.com for Radiator AAA server software
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-- 
Heikki Vatiainen
OSC, makers of Radiator
Visit radiatorsoftware.com for Radiator AAA server software