Re: [exim] Problems with ldap lookup and doubling comma in …

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Author: Daniel Betz
Date:  
To: Mike Brudenell, exim-users@exim.org
Subject: Re: [exim] Problems with ldap lookup and doubling comma in userPassword field
Hi Mike,


thanks for your answer.


No, the quoting isnt the problem.
I dont want to use ldapauth with an constructed ldap_dn, because i need some other values from the full ldap lookup.

When using the examples as described in the specification, it always do two ldap lookups.
One to construct the bind DN for the user and one to ldapauth the user against the ldap.

My idea was to do one lookup in the ldap and extract all the fields that i need (e.g. spamaction, filters, spf actions, dkim key )
and later to do authentification with crypteq{} against $auth2/3 and the crypted userPassword field in the ldap lookup.

This takes me only one ldap lookup and will double the performance against ldap.

But now i have the problem, that the change https://bugs.exim.org/show_bug.cgi?id=660 ALWAYS doubles colons ( , comma or komma in german )
+          for (j = 0; j < len; j++)
+            {
+            if (value[j] == ',')
+              data = string_cat(data, &size, &ptr, US",,", 2);
+            else
+              data = string_cat(data, &size, &ptr, value+j, 1);
+            }
+          }


That destroys the extracted sha512 crypt when there is an colon/comma in.

Best Regards,
Daniel

 









Von: Mike Brudenell <mike.brudenell@???>
Gesendet: Donnerstag, 25. Mai 2017 12:03
An: exim-users@???
Betreff: Re: [exim] Problems with ldap lookup and doubling comma in userPassword field
 

Hi, Daniel -


Is the problem that you've forgotten to use Exim's quoting features on the username and password when constructing the LDAP lookup?


For example the Specification gives examples such as this for ldapauth:



server_condition = ${if and{{ \
      !eq{}{$auth1} }{ \
      ldapauth{\
        user="uid=${quote_ldap_dn:$auth1},ou=people,o=example.org" \
        pass=${quote:$auth2} \
        ldap://ldap.example.org/} }} }


And a later example in the TLS Authenticator section implies that an ldap lookup should also be using quoting:


server_condition =  ${if forany {$auth1} \


                          {!= {0} \
                              {${lookup ldap{ldap:///\
                       mailname=${quote_ldap_dn:${lc:$item}},\
                       ou=users,LDAP_DC?mailid} {$value}{0} \
                     } } }}


Cheers,
Mike B-)






On 24 May 2017 at 10:58, Daniel Betz <dbetz@???> wrote:
Hello list,

i have an problem, which has to do with the change https://bugs.exim.org/show_bug.cgi?id=660

My plan is to reduce LDAP queries and enable an admin password for mail accounts.

The userPassword and adminPassword fields in ldap are base64 encoded sha512 crypt, which can include ","
Problem is, that they get doubled by the patch above, although i have tried an other seperator like : LDAP_LOOKUP_USER_PLAIN = <\n ${lookup ldap.
but the doubling of , is hardcoded into the source.

Debug Log shows this:

exim[13496]: 13506 LDAP value loop userPassword:{crypt}$6$,7_X.clF$OHzHUqADeV9ijFJn9EsB0LMp7iL7PYVNdjUtLblOvch9lGkv7G9jnvU.jUqWL61tg1352IMSVHtdJ0FUA1akT1
exim[13496]: 13506 lookup yielded: id="4029359" objectClass="qmailUser,person" [...] userPassword="{crypt}$6$,,7_X.clF$OHzHUqADeV9ijFJn9EsB0LMp7iL7PYVNdjUtLblOvch9lGkv7G9jnvU.jUqWL61tg1352IMSVHtdJ0FUA1akT1"

Here you can see the doubling of the ,, in the lookup. Therefore authentification with crypteq{} will fail.

It would be nice, when i can change the separator for ldap lookups, so that i must noch manually patch the src/lookups/ldap.c



My config looks like this:
LDAP_LOOKUP_USER_PLAIN = ${lookup ldap {\
                                nettime=3 time=5 user=LDAP_USER pass=LDAP_PASS referrals=nofollow \
                                ldapi:///LDAP_BASEDN??sub?(&(!(accountstatus=inactive))(|(uid=${quote_ldap:$auth2})(mail=${quote_ldap:$auth2})))\
                          }}
LDAP_LOOKUP_USER_LOGIN = ${lookup ldap {\
                                nettime=3 time=5 user=LDAP_USER pass=LDAP_PASS referrals=nofollow \
                                ldapi:///LDAP_BASEDN??sub?(&(!(accountstatus=inactive))(|(uid=${quote_ldap:$auth1})(mail=${quote_ldap:$auth1})))\
                          }}


plain:
  driver = plaintext
  public_name = PLAIN
  server_prompts = :
  server_condition = ${if or {\
                                {crypteq{$auth3}{${extract{userPassword}{LDAP_LOOKUP_USER_PLAIN}}}}\
                                {crypteq{$auth3}{${extract{adminPassword}{LDAP_LOOKUP_USER_PLAIN}}}}\
                     }{yes}{no}}
  server_set_id = $auth2


login:
  driver = plaintext
  public_name = LOGIN
  server_prompts = Username:: : Password::
  server_condition = ${if or {\
                                {crypteq{$auth2}{${extract{userPassword}{LDAP_LOOKUP_USER_LOGIN}}}}\
                                {crypteq{$auth2}{${extract{adminPassword}{LDAP_LOOKUP_USER_LOGIN}}}}\
                     }{yes}{no}}
  server_set_id = $auth1



Freundliche Grüße,

Daniel Betz
System Design Engineer / Senior Systemadministration
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