Getting a string 'as is' with no escapes from LDAP
Kostas Zorbadelos
kzorba at otenet.gr
Wed Sep 12 10:27:17 CEST 2018
Quick update, I found a workaround in my case.
I map the ldap attribute to a binary attribute and in case for any
reason this fails, I use Auth-Type ldap as last resort.
My policy now looks like this:
authorize {
...
# set Cleartext-Password from LDAP in a way that avoids
# freeradius string escaping rules
if (&control:Tmp-Octets-0) {
update control {
Cleartext-Password := "%{string:&control:Tmp-Octets-0}"
}
}
else {
update {
control:Auth-Type := ldap_1
}
}
...
}
authenticate {
...
ldap_1
}
This seems to work. In any case, I consider it an issue that we cannot
retrieve a string 'as is' out of an LDAP backend (and perhaps other
backends too).
Any thoughts/input highly welcome.
Regards,
Kostas
On Τετ, Σεπ 12 2018 at 09:42:38 πμ, Kostas Zorbadelos <kzorba at otenet.gr> wrote:
> Hello all,
>
> I think a new thread is better for this discussion. In a previous thread
> (http://lists.freeradius.org/pipermail/freeradius-users/2018-September/092606.html)
> I raised the issue of failing to get a string as is from an LDAP
> backend. The string represents the clear text password and I would like
> to take it 'as is' with no escaping of any kind.
>
> I got the explanation about the shell rules that are now implemented in
> freeradius 3 for strings, so as to get a single uniform approach to
> freeradius 3 and fix the inconsistencies of string handling in
> freeradius 2.
>
> We got to the solution of mapping the LDAP attribute as a binary
> attribute, say Tmp-Octets-0 and then use the following policy:
>
> if (control:Tmp-Octets-0) {
> update control {
> Cleartext-Password := "%{string:control:Tmp-Octets-0}"
> }
> }
>
> The binary attribute would need to be converted to string for the
> comparison in pap to work.
>
> Now, we found a problem for strings beginning with '0x' :)
>
> Example 1 (passwd '0xtest123')
> --------------------------------
> kzorba at devradius(0)[09:34 AM]~/radius->/opt/freeradius/bin/radclient -f test_kzorba1.txt -x 79.128.176.142:1812 auth testing123
> Sending Access-Request of id 178 to 79.128.176.142 port 1812
> User-Name = "kzorba1 at otenet.gr"
> NAS-Port-Type = xDSL
> User-Password = "0xtest123"
> NAS-Port-Id = "#DSLAM PORT DESCRIPTION HERE#"
> Calling-Station-Id = "BNG INTERFACE # DSLAM PORT DESCRIPTION"
> NAS-Port = 12234455
> rad_recv: Access-Reject packet from host 79.128.176.142 port 1812, id=178, length=20
>
> (0) Received Access-Request Id 99 from 79.128.176.142:50436 to 79.128.176.142:1812 length 140
> (0) User-Name = "kzorba1 at otenet.gr"
> (0) NAS-Port-Type = xDSL
> (0) User-Password = "0xtest123"
> (0) NAS-Port-Id = "#DSLAM PORT DESCRIPTION HERE#"
> (0) Calling-Station-Id = "BNG INTERFACE # DSLAM PORT DESCRIPTION"
> (0) NAS-Port = 12234455
> (0) # Executing section authorize from file /opt/freeradius-3.0.17/etc/raddb/sites-enabled/cisco-bng
> (0) authorize {
> (0) [preprocess] = ok
> (0) [chap] = noop
> (0) [mschap] = noop
> ...
> rlm_ldap (ldap_1): Reserved connection (0)
> ...
> (0) ldap_1: Performing search in "..." with filter "...", scope "sub"
> (0) ldap_1: Waiting for search result...
> (0) ldap_1: User object found at DN "..."
> (0) ldap_1: Processing user attributes
> ...
> (0) ldap_1: WARNING: Failed parsing value "0xtest123" for attribute Tmp-Octets-0: Length of Hex String is not even, got 7 bytes
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> (0) ldap_1: No attributes updated
> (0) ldap_1: reply:Framed-IP-Address = 62.103.131.9
> rlm_ldap (ldap_1): Released connection (0)
> (0) [ldap_1] = updated
> ...
> (0) pap: WARNING: No "known good" password found for the user. Not setting Auth-Type
> (0) pap: WARNING: Authentication will fail unless a "known good" password is available
> (0) [pap] = noop
> (0) } # authorize = updated
> (0) ERROR: No Auth-Type found: rejecting the user via Post-Auth-Type = Reject
> (0) Failed to authenticate the user
> (0) Using Post-Auth-Type Reject
> (0) # Executing group from file /opt/freeradius-3.0.17/etc/raddb/sites-enabled/cisco-bng
> (0) Post-Auth-Type REJECT {
> (0) attr_filter.access_reject: EXPAND %{User-Name}
> (0) attr_filter.access_reject: --> kzorba1 at otenet.gr
> (0) attr_filter.access_reject: Matched entry DEFAULT at line 11
> (0) [attr_filter.access_reject] = updated
> (0) } # Post-Auth-Type REJECT = updated
> (0) Login incorrect (No Auth-Type found: rejecting the user via Post-Auth-Type = Reject): [kzorba1 at otenet.gr] (from client myself port 12234455 cli BNG INTERFACE # DSLAM PORT DESC
> RIPTION)
> (0) Delaying response for 1.000000 seconds
> Waking up in 0.3 seconds.
>
> Example 2 (passwd '0xtest1234')
> --------------------------------
> kzorba at devradius(0)[09:39 AM]~/radius->/opt/freeradius/bin/radclient -f test_kzorba1.txt -x 79.128.176.142:1812 auth testing123
> Sending Access-Request of id 85 to 79.128.176.142 port 1812
> User-Name = "kzorba1 at otenet.gr"
> NAS-Port-Type = xDSL
> User-Password = "0xtest1234"
> NAS-Port-Id = "#DSLAM PORT DESCRIPTION HERE#"
> Calling-Station-Id = "BNG INTERFACE # DSLAM PORT DESCRIPTION"
> NAS-Port = 12234455
> rad_recv: Access-Reject packet from host 79.128.176.142 port 1812, id=85, length=20
>
> (0) Received Access-Request Id 85 from 79.128.176.142:38359 to 79.128.176.142:1812 length 140
> (0) User-Name = "kzorba1 at otenet.gr"
> (0) NAS-Port-Type = xDSL
> (0) User-Password = "0xtest1234"
> (0) NAS-Port-Id = "#DSLAM PORT DESCRIPTION HERE#"
> (0) Calling-Station-Id = "BNG INTERFACE # DSLAM PORT DESCRIPTION"
> (0) NAS-Port = 12234455
> (0) # Executing section authorize from file /opt/freeradius-3.0.17/etc/raddb/sites-enabled/cisco-bng
> (0) authorize {
> ...
> (0) ldap_1: WARNING: Failed parsing value "0xtest1234" for attribute Tmp-Octets-0: Invalid hex data
> (0) ldap_1: No attributes updated
> ...
>
> Is there a way to overcome this?
> Generally speaking a solution is needed to get a string 'as is' out of
> an LDAP backend (most probably this will affect other backends too)
> without escaping/unescaping of any kind.
>
> Regards,
> Kostas
--
Kostas Zorbadelos http://gr.linkedin.com/in/kzorba
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