Problem with external authentication script

7 Jun 2009

      Hello.

I have some trouble to call an external authentication script in freeradius.

I want to use MOTP for authentication. MOTP uses a shell-script
(/usr/local/bin/otpverify.sh) to verify the given password. The script
needs five arguments (User, One-Time-Password, Secret, PIN and Offset).

My system is a fresh installation of freeradius on a Debian/Lenny system.

I did the following changes on the following config-files:

1. A new dictionary-file (included in /etc/freeradius/dictionary):
    /etc/freeradius/dictionary.motp
    -------------------------------
    ATTRIBUTE       Secret                  960     string
    ATTRIBUTE       PIN                     961     string
    ATTRIBUTE       Offset                  962     string

2. A new module in
    /etc/freeradius/radiusd.conf (modules-section):
    ----------------------------
    [...]
    exec motp {
         wait = yes
         program = "/usr/local/bin/otpverify.sh %{User-Name}
%{User-Password} %{Secret} %{PIN} %{Offset}"
         input_pairs = request
         output_pairs = config
    }
    [...]

3. /etc/freeradius/sites-enabled/default (section authenticate)
    -------------------------------------
    [...]
    Auth-Type MOTP {
         motp
    }

4. /etc/freeradius/users
    ---------------------
    DEFAULT Auth-Type = Accept
         Exec-Program-Wait = "/usr/local/bin/otpverify.sh '%{User-Name}'
'%{User-Password}' '%{Secret}' '%{PIN}' '%{Offset}'",
         Fall-Through = Yes

    stefan
         Secret = 143a5c6fa125ac1f,
         PIN = 1234,
         Offset = 0

The main-problem is: freeradius didn't call the script with all the
needed arguments - so the authentication failes:

[...]
         expand: /usr/local/bin/otpverify.sh '%{User-Name}'
'%{User-Password}' '%{Secret}' '%{PIN}' '%{Offset}' ->
/usr/local/bin/otpverify.sh 'stefan' '123' '' '' ''
[...]

Can anybody tell me where I did the mistake in my configuration ??

Thanks a lot
Stefan

P.S.
Here is the complete debugging output:

FreeRADIUS Version 2.0.4, for host x86_64-pc-linux-gnu, built on Sep  7
2008 at 17:42:33
Copyright (C) 1999-2008 The FreeRADIUS server project and contributors.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
You may redistribute copies of FreeRADIUS under the terms of the
GNU General Public License.
Starting - reading configuration files ...
including configuration file /etc/freeradius/radiusd.conf
including configuration file /etc/freeradius/proxy.conf
including configuration file /etc/freeradius/clients.conf
including configuration file /etc/freeradius/snmp.conf
including configuration file /etc/freeradius/eap.conf
including configuration file /etc/freeradius/policy.conf
including files in directory /etc/freeradius/sites-enabled/
including configuration file /etc/freeradius/sites-enabled/default
including configuration file /etc/freeradius/sites-enabled/inner-tunnel
including dictionary file /etc/freeradius/dictionary
main {
         prefix = "/usr"
         localstatedir = "/var"
         logdir = "/var/log/freeradius"
         libdir = "/usr/lib/freeradius"
         radacctdir = "/var/log/freeradius/radacct"
         hostname_lookups = no
         max_request_time = 30
         cleanup_delay = 5
         max_requests = 1024
         allow_core_dumps = no
         pidfile = "/var/run/freeradius/freeradius.pid"
         user = "freerad"
         group = "freerad"
         checkrad = "/usr/sbin/checkrad"
         debug_level = 0
         proxy_requests = yes
  security {
         max_attributes = 200
         reject_delay = 1
         status_server = yes
  }
}
  client localhost {
         ipaddr = 127.0.0.1
         require_message_authenticator = no
         secret = "testing123"
         nastype = "other"
  }
  client 192.168.82.41 {
         require_message_authenticator = no
         secret = "testing123"
  }
  client 192.168.82.40 {
         require_message_authenticator = no
         secret = "testing123"
  }
radiusd: #### Loading Realms and Home Servers ####
  proxy server {
         retry_delay = 5
         retry_count = 3
         default_fallback = no
         dead_time = 120
         wake_all_if_all_dead = no
  }
  home_server localhost {
         ipaddr = 127.0.0.1
         port = 1812
         type = "auth"
         secret = "testing123"
         response_window = 20
         max_outstanding = 65536
         zombie_period = 40
         status_check = "status-server"
         ping_check = "none"
         ping_interval = 30
         check_interval = 30
         num_answers_to_alive = 3
         num_pings_to_alive = 3
         revive_interval = 120
         status_check_timeout = 4
  }
  home_server_pool my_auth_failover {
         type = fail-over
         home_server = localhost
  }
  realm example.com {
         auth_pool = my_auth_failover
  }
  realm LOCAL {
  }
radiusd: #### Instantiating modules ####
  instantiate {
  Module: Linked to module rlm_exec
  Module: Instantiating exec
   exec {
         wait = yes
         input_pairs = "request"
         shell_escape = yes
   }
  Module: Linked to module rlm_expr
  Module: Instantiating expr
  Module: Linked to module rlm_expiration
  Module: Instantiating expiration
   expiration {
         reply-message = "Password Has Expired  "
   }
  Module: Linked to module rlm_logintime
  Module: Instantiating logintime
   logintime {
         reply-message = "You are calling outside your allowed timespan  "
         minimum-timeout = 60
   }
  }
radiusd: #### Loading Virtual Servers ####
server inner-tunnel {
  modules {
  Module: Checking authenticate {...} for more modules to load
  Module: Instantiating motp
   exec motp {
         wait = yes
         program = "/usr/local/bin/otpverify.sh %{User-Name}
%{User-Password} %{Secret} %{PIN} %{Offset}"
         input_pairs = "request"
         output_pairs = "config"
         shell_escape = yes
   }
  Module: Linked to module rlm_pap
  Module: Instantiating pap
   pap {
         encryption_scheme = "auto"
         auto_header = no
   }
  Module: Linked to module rlm_chap
  Module: Instantiating chap
  Module: Linked to module rlm_mschap
  Module: Instantiating mschap
   mschap {
         use_mppe = yes
         require_encryption = no
         require_strong = no
         with_ntdomain_hack = no
   }
  Module: Linked to module rlm_unix
  Module: Instantiating unix
   unix {
         radwtmp = "/var/log/freeradius/radwtmp"
   }
  Module: Linked to module rlm_eap
  Module: Instantiating eap
   eap {
         default_eap_type = "md5"
         timer_expire = 60
         ignore_unknown_eap_types = no
         cisco_accounting_username_bug = no
   }
  Module: Linked to sub-module rlm_eap_md5
  Module: Instantiating eap-md5
  Module: Linked to sub-module rlm_eap_leap
  Module: Instantiating eap-leap
  Module: Linked to sub-module rlm_eap_gtc
  Module: Instantiating eap-gtc
    gtc {
         challenge = "Password: "
         auth_type = "PAP"
    }
rlm_eap: Ignoring EAP-Type/tls because we do not have OpenSSL support.
rlm_eap: Ignoring EAP-Type/ttls because we do not have OpenSSL support.
rlm_eap: Ignoring EAP-Type/peap because we do not have OpenSSL support.
  Module: Linked to sub-module rlm_eap_mschapv2
  Module: Instantiating eap-mschapv2
    mschapv2 {
         with_ntdomain_hack = no
    }
  Module: Checking authorize {...} for more modules to load
  Module: Linked to module rlm_realm
  Module: Instantiating suffix
   realm suffix {
         format = "suffix"
         delimiter = "@"
         ignore_default = no
         ignore_null = no
   }
  Module: Linked to module rlm_files
  Module: Instantiating files
   files {
         usersfile = "/etc/freeradius/users"
         acctusersfile = "/etc/freeradius/acct_users"
         preproxy_usersfile = "/etc/freeradius/preproxy_users"
         compat = "no"
   }
  Module: Checking session {...} for more modules to load
  Module: Linked to module rlm_radutmp
  Module: Instantiating radutmp
   radutmp {
         filename = "/var/log/freeradius/radutmp"
         username = "%{User-Name}"
         case_sensitive = yes
         check_with_nas = yes
         perm = 384
         callerid = yes
   }
  Module: Checking post-proxy {...} for more modules to load
  Module: Checking post-auth {...} for more modules to load
  Module: Linked to module rlm_attr_filter
  Module: Instantiating attr_filter.access_reject
   attr_filter attr_filter.access_reject {
         attrsfile = "/etc/freeradius/attrs.access_reject"
         key = "%{User-Name}"
   }
  }
}
server {
  modules {
  Module: Checking authenticate {...} for more modules to load
  Module: Checking authorize {...} for more modules to load
  Module: Linked to module rlm_preprocess
  Module: Instantiating preprocess
   preprocess {
         huntgroups = "/etc/freeradius/huntgroups"
         hints = "/etc/freeradius/hints"
         with_ascend_hack = no
         ascend_channels_per_line = 23
         with_ntdomain_hack = no
         with_specialix_jetstream_hack = no
         with_cisco_vsa_hack = no
         with_alvarion_vsa_hack = no
   }
  Module: Checking preacct {...} for more modules to load
  Module: Linked to module rlm_acct_unique
  Module: Instantiating acct_unique
   acct_unique {
         key = "User-Name, Acct-Session-Id, NAS-IP-Address,
Client-IP-Address, NAS-Port"
   }
  Module: Checking accounting {...} for more modules to load
  Module: Linked to module rlm_detail
  Module: Instantiating detail
   detail {
         detailfile =
"/var/log/freeradius/radacct/%{Client-IP-Address}/detail-%Y%m%d"
         header = "%t"
         detailperm = 384
         dirperm = 493
         locking = no
         log_packet_header = no
   }
  Module: Instantiating attr_filter.accounting_response
   attr_filter attr_filter.accounting_response {
         attrsfile = "/etc/freeradius/attrs.accounting_response"
         key = "%{User-Name}"
   }
  Module: Checking session {...} for more modules to load
  Module: Checking post-proxy {...} for more modules to load
  Module: Checking post-auth {...} for more modules to load
  }
}
radiusd: #### Opening IP addresses and Ports ####
listen {
         type = "auth"
         ipaddr = *
         port = 0
}
listen {
         type = "acct"
         ipaddr = *
         port = 0
}
main {
         snmp = no
         smux_password = ""
         snmp_write_access = no
}
Listening on authentication address * port 1812
Listening on accounting address * port 1813
Listening on proxy address * port 1814
Ready to process requests.
rad_recv: Access-Request packet from host 192.168.82.40 port 1026,
id=43, length=78
         User-Name = "stefan"
         User-Password = "123"
         Service-Type = Authenticate-Only
         NAS-Identifier = "ubuntu.kuegler.org"
         NAS-IP-Address = 192.168.82.40
+- entering group authorize
++[preprocess] returns ok
++[chap] returns noop
++[mschap] returns noop
     rlm_realm: No '@' in User-Name = "stefan", looking up realm NULL
     rlm_realm: No such realm "NULL"
++[suffix] returns noop
   rlm_eap: No EAP-Message, not doing EAP
++[eap] returns noop
++[unix] returns updated
     users: Matched entry DEFAULT at line 2
         expand: /usr/local/bin/otpverify.sh '%{User-Name}'
'%{User-Password}' '%{Secret}' '%{PIN}' '%{Offset}' ->
/usr/local/bin/otpverify.sh 'stefan' '123' '' '' ''
     users: Matched entry stefan at line 9
++[files] returns ok
++[expiration] returns noop
++[logintime] returns noop
rlm_pap: Found existing Auth-Type, not changing it.
++[pap] returns noop
   rad_check_password:  Found Auth-Type Accept
   rad_check_password: Auth-Type = Accept, accepting the user
Login OK: [stefan/123] (from client 192.168.82.40 port 0)
+- entering group post-auth
Exec-Program output: FAIL
Exec-Program-Wait: plaintext: FAIL
Exec-Program: returned: 3
Login incorrect (external check said so)
++[exec] returns reject
   Found Post-Auth-Type Reject
+- entering group REJECT
         expand: %{User-Name} -> stefan
  attr_filter: Matched entry DEFAULT at line 11
++[attr_filter.access_reject] returns updated
Delaying reject of request 0 for 1 seconds
Going to the next request
Waking up in 0.9 seconds.
rad_recv: Access-Request packet from host 192.168.82.40 port 1026,
id=43, length=78
Waiting to send Access-Reject to client 192.168.82.40 port 1026 - ID: 43
Sending delayed reject for request 0
Sending Access-Reject of id 43 to 192.168.82.40 port 1026
Waking up in 4.9 seconds.

Problem with external authentication script

Stefan Kuegler