LDAP virtual user username being rewritten:

Coy Hile coy.hile at coyhile.com
Sat May 21 19:40:34 UTC 2022


Replying to myself…

Empirically, changing the following two lines in the LDAP configuration seems to have worked:

user_filter = (&(objectClass=posixAccount)(uid=%n))

and

pass_filter = (&(objectClass=posixAccount)(uid=%n))


My question remains, though, why was the original username getting rewritten by default?

-c

> On May 21, 2022, at 3:18 PM, Coy Hile <coy.hile at coyhile.com> wrote:
> 
> Hi all,
> 
> I’m working on migrating a dovecot instance that formerly had its only user (me) stored in a SQL database to a new instance that uses LDAP so I don’t have to maintain a handful of different passwords.  However, I’m ending up getting sent to an incorrect mailbox because the %d part of the username I enter is getting stripped somewhere along the lines. Dovecot debug logs show this happening here:
> 
> May 21 18:36:53 auth: Debug: client in: AUTH    1       PLAIN   service=imap    secured session=itEO5InfPJusEgKD        lip=172.18.2.131        rip=172.18.2.131        lport=143       rport=39740     resp=<hidden>
> May 21 18:36:53 auth: Debug: ldap(hile at coyhile.com,172.18.2.131,<itEO5InfPJusEgKD>): Performing passdb lookup
> May 21 18:36:53 auth: Debug: ldap(hile at coyhile.com,172.18.2.131,<itEO5InfPJusEgKD>): pass search: base=ou=People,dc=coyhile,dc=com scope=subtree filter=(&(objectClass=posixAccount)(uid=hile)) fields=uid,userPassword
> May 21 18:36:53 auth: Debug: ldap(hile at coyhile.com,172.18.2.131,<itEO5InfPJusEgKD>): result: uid=hile userPassword=<hidden>; uid,userPassword unused
> May 21 18:36:53 auth: Debug: ldap(hile at coyhile.com,172.18.2.131,<itEO5InfPJusEgKD>): username changed hile at coyhile.com -> hile
> May 21 18:36:53 auth: Debug: ldap(hile,172.18.2.131,<itEO5InfPJusEgKD>): Finished passdb lookup
> May 21 18:36:53 auth: Debug: auth(hile,172.18.2.131,<itEO5InfPJusEgKD>): Auth request finished
> May 21 18:36:53 auth: Debug: client passdb out: OK      1       user=hile               original_user=hile at coyhile.com
> May 21 18:36:53 auth: Debug: master in: REQUEST 473956353       9409    1       2c1f94ded4de2c343425c90eeee8d094        session_pid=9412        request_auth_token
> May 21 18:36:53 auth: Debug: ldap(hile,172.18.2.131,<itEO5InfPJusEgKD>): Performing userdb lookup
> May 21 18:36:53 auth: Debug: ldap(hile,172.18.2.131,<itEO5InfPJusEgKD>): user search: base=ou=People,dc=coyhile,dc=com scope=subtree filter=(&(objectClass=posixAccount)(uid=hile)) fields=homeDirectory,uidNumber,gidNumber
> May 21 18:36:53 auth: Debug: ldap(hile,172.18.2.131,<itEO5InfPJusEgKD>): result: homeDirectory=/home/hile uidNumber=10000 gidNumber=10000; homeDirectory,uidNumber,gidNumber unused
> May 21 18:36:53 auth: Debug: ldap(hile,172.18.2.131,<itEO5InfPJusEgKD>): Finished userdb lookup
> May 21 18:36:53 auth: Debug: master userdb out: USER    473956353       hile    home=/data/mail/vmail//hile     uid=998 gid=998 auth_token=3a262da408d33ce2c51ecb1ddd943203fdbb17a3     auth_user=hile at coyhile.com
> 
> 
> Note the “username changed” line above. Clearly I’ve misconfigured something, butI am unsure what. My configuration is as follows:
> 
> root at basement-imap01:/var/log# doveconf -n
> # 2.3.7.2 (3c910f64b): /etc/dovecot/dovecot.conf
> # Pigeonhole version 0.5.7.2 ()
> # OS: Linux 5.4.0-110-generic x86_64 Ubuntu 20.04.4 LTS
> # Hostname: basement-imap01.coyhile.com
> auth_debug = yes
> debug_log_path = /var/log/dovecot-debug.log
> doveadm_password = # hidden, use -P to show it
> mail_location = maildir:~/Maildir
> mail_privileged_group = mail
> namespace inbox {
>  inbox = yes
>  location =
>  mailbox Drafts {
>    special_use = \Drafts
>  }
>  mailbox Junk {
>    special_use = \Junk
>  }
>  mailbox Sent {
>    special_use = \Sent
>  }
>  mailbox "Sent Messages" {
>    special_use = \Sent
>  }
>  mailbox Trash {
>    special_use = \Trash
>  }
>  prefix =
> }
> passdb {
>  args = /etc/dovecot/dovecot-ldap.conf.ext
>  driver = ldap
> }
> protocols = " imap lmtp"
> service aggregator {
>  fifo_listener replication-notify-fifo {
>    mode = 0666
>    user = vmail
>  }
>  unix_listener replication-notify {
>    mode = 0666
>    user = vmail
>  }
> }
> service doveadm {
>  inet_listener {
>    port = 12345
>  }
>  user = vmail
> }
> service replicator {
>  unix_listener replicator-doveadm {
>    mode = 0666
>  }
> }
> ssl_cert = </etc/dovecot/private/dovecot.pem
> ssl_client_ca_dir = /etc/ssl/certs
> ssl_dh = # hidden, use -P to show it
> ssl_key = # hidden, use -P to show it
> userdb {
>  args = /etc/dovecot/dovecot-ldap.conf.ext
>  driver = ldap
>  override_fields = uid=vmail gid=vmail home=/data/mail/vmail/%d/%n
> }
> root at basement-imap01:/var/log#
> 
> with the dovecot-ldap.conf.ext as follows:
> 
> root at basement-imap01:/etc/dovecot# cat dovecot-ldap.conf.ext
> # This file is commonly accessed via passdb {} or userdb {} section in
> # conf.d/auth-ldap.conf.ext
> 
> # This file is opened as root, so it should be owned by root and mode 0600.
> #
> # http://wiki2.dovecot.org/AuthDatabase/LDAP
> #
> # NOTE: If you're not using authentication binds, you'll need to give
> # dovecot-auth read access to userPassword field in the LDAP server.
> # With OpenLDAP this is done by modifying /etc/ldap/slapd.conf. There should
> # already be something like this:
> 
> # access to attribute=userPassword
> #        by dn="<dovecot's dn>" read # add this
> #        by anonymous auth
> #        by self write
> #        by * none
> 
> # Space separated list of LDAP hosts to use. host:port is allowed too.
> #hosts =
> hosts = ldap.coyhile.com
> 
> # LDAP URIs to use. You can use this instead of hosts list. Note that this
> # setting isn't supported by all LDAP libraries.
> #uris =
> 
> # Distinguished Name - the username used to login to the LDAP server.
> # Leave it commented out to bind anonymously (useful with auth_bind=yes).
> #dn =
> dn = uid=dovecotquery,ou=people,dc=coyhile,dc=com
> 
> # Password for LDAP server, if dn is specified.
> #dnpass =
> dnpass = [REDACTED]
> 
> # Use SASL binding instead of the simple binding. Note that this changes
> # ldap_version automatically to be 3 if it's lower.
> #sasl_bind = no
> # SASL mechanism name to use.
> #sasl_mech =
> # SASL realm to use.
> #sasl_realm =
> # SASL authorization ID, ie. the dnpass is for this "master user", but the
> # dn is still the logged in user. Normally you want to keep this empty.
> #sasl_authz_id =
> 
> # Use TLS to connect to the LDAP server.
> #tls = no
> # TLS options, currently supported only with OpenLDAP:
> #tls_ca_cert_file =
> #tls_ca_cert_dir =
> #tls_cipher_suite =
> # TLS cert/key is used only if LDAP server requires a client certificate.
> #tls_cert_file =
> #tls_key_file =
> # Valid values: never, hard, demand, allow, try
> #tls_require_cert =
> 
> # Use the given ldaprc path.
> #ldaprc_path =
> 
> # LDAP library debug level as specified by LDAP_DEBUG_* in ldap_log.h.
> # -1 = everything. You may need to recompile OpenLDAP with debugging enabled
> # to get enough output.
> #debug_level = 0
> 
> # Use authentication binding for verifying password's validity. This works by
> # logging into LDAP server using the username and password given by client.
> # The pass_filter is used to find the DN for the user. Note that the pass_attrs
> # is still used, only the password field is ignored in it. Before doing any
> # search, the binding is switched back to the default DN.
> #auth_bind = no
> 
> # If authentication binding is used, you can save one LDAP request per login
> # if users' DN can be specified with a common template. The template can use
> # the standard %variables (see user_filter). Note that you can't
> # use any pass_attrs if you use this setting.
> #
> # If you use this setting, it's a good idea to use a different
> # dovecot-ldap.conf.ext for userdb (it can even be a symlink, just as long as
> # the filename is different in userdb's args). That way one connection is used
> # only for LDAP binds and another connection is used for user lookups.
> # Otherwise the binding is changed to the default DN before each user lookup.
> #
> # For example:
> #   auth_bind_userdn = cn=%u,ou=people,o=org
> #
> #auth_bind_userdn =
> 
> # LDAP protocol version to use. Likely 2 or 3.
> #ldap_version = 3
> 
> # LDAP base. %variables can be used here.
> # For example: dc=mail, dc=example, dc=org
> base = ou=People,dc=coyhile,dc=com
> 
> # Dereference: never, searching, finding, always
> #deref = never
> 
> # Search scope: base, onelevel, subtree
> #scope = subtree
> scope = subtree
> 
> # User attributes are given in LDAP-name=dovecot-internal-name list. The
> # internal names are:
> #   uid - System UID
> #   gid - System GID
> #   home - Home directory
> #   mail - Mail location
> #
> # There are also other special fields which can be returned, see
> # http://wiki2.dovecot.org/UserDatabase/ExtraFields
> #user_attrs = homeDirectory=home,uidNumber=uid,gidNumber=gid
> 
> # Filter for user lookup. Some variables can be used (see
> # http://wiki2.dovecot.org/Variables for full list):
> #   %u - username
> #   %n - user part in user at domain, same as %u if there's no domain
> #   %d - domain part in user at domain, empty if user there's no domain
> #user_filter = (&(objectClass=posixAccount)(uid=%u))
> user_filter = (&(objectClass=posixAccount)(uid=%u))
> 
> # Password checking attributes:
> #  user: Virtual user name (user at domain), if you wish to change the
> #        user-given username to something else
> #  password: Password, may optionally start with {type}, eg. {crypt}
> # There are also other special fields which can be returned, see
> # http://wiki2.dovecot.org/PasswordDatabase/ExtraFields
> #pass_attrs = uid=user,userPassword=password
> 
> # If you wish to avoid two LDAP lookups (passdb + userdb), you can use
> # userdb prefetch instead of userdb ldap in dovecot.conf. In that case you'll
> # also have to include user_attrs in pass_attrs field prefixed with "userdb_"
> # string. For example:
> #pass_attrs = uid=user,userPassword=password,\
> #  homeDirectory=userdb_home,uidNumber=userdb_uid,gidNumber=userdb_gid
> 
> # Filter for password lookups
> #pass_filter = (&(objectClass=posixAccount)(uid=%u))
> pass_filter = (&(objectClass=posixAccount)(uid=%n))
> 
> # Attributes and filter to get a list of all users
> #iterate_attrs = uid=user
> iterate_attrs = maildrop=user
> iterate_filter = (objectClass=posixAccount)
> 
> # Default password scheme. "{scheme}" before password overrides this.
> # List of supported schemes is in: http://wiki2.dovecot.org/Authentication
> #default_pass_scheme = CRYPT
> 
> # By default all LDAP lookups are performed by the auth master process.
> # If blocking=yes, auth worker processes are used to perform the lookups.
> # Each auth worker process creates its own LDAP connection so this can
> # increase parallelism. With blocking=no the auth master process can
> # keep 8 requests pipelined for the LDAP connection, while with blocking=yes
> # each connection has a maximum of 1 request running. For small systems the
> # blocking=no is sufficient and uses less resources.
> #blocking = no
> root at basement-imap01:/etc/dovecot#
> 
> --
> Coy Hile
> coy.hile at coyhile.com
> 
> 
> 
> 

--
Coy Hile
coy.hile at coyhile.com




-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: Message signed with OpenPGP
URL: <https://dovecot.org/pipermail/dovecot/attachments/20220521/720cf637/attachment-0001.sig>


More information about the dovecot mailing list