Deliver mail to virtual users with sendmail and dovecot lda

dovecotsendmail

I'm trying to migrate our linux system user based post system to virtual users.

I have

  • sendmail with procmail delivery
  • dovecot
  • system users with different uids
  • roundcube web interface

Sendmail handles all mail delivery to user mailboxes, dovecot handles pop3 and imap interraction with users, everything is working like a charm

Now we start to implement active directory globally and i want to refuse from linux system email users prior to ldap virutal users.

I enabled sendmail ldap_routing

define(`confLDAP_DEFAULT_SPEC', `-h "10.1.0.1" -b "ou=portal,dc=univ,dc=priv" -d "cn=portal admin,ou=portal,dc=univ,dc=priv" -MLDAP_AUTH_SIMPLE -P/etc/mail/ldap_pass')dnl

LDAPROUTE_DOMAIN_FILE(`/etc/mail/ldap_route_domains')dnl

FEATURE(`ldap_routing', `null', `ldap -1 -T -v sAMAccountName -k (&(|(objectclass=user)(objectclass=group))(|(mail=%0)(proxyAddresses=smtp:%0)))',`passthru')dnl

created simple alias file for ldap users via perl script. File initially looked like this

sAMAccountName1:    vmail
sAMAccountName2:    vmail
....
sAMAccountNameN:    vmail

enabled dovecot-lda using this howto

Unfortunately sendmail passes real system user name ("vmail" in my case) as -d argument, not sAMAccountName of virtial user with this configuration.

After that i modify my alias file in something like this (inspired by this topic)

sAMAccountName1:    "|/usr/libexec/dovecot/dovecot-lda -d sAMAccountName1"
sAMAccountName2:    "|/usr/libexec/dovecot/dovecot-lda -d sAMAccountName1"
....
sAMAccountNameN:    "|/usr/libexec/dovecot/dovecot-lda -d sAMAccountName1"

This solution fails because of system right problem i can't solve. Here's log messages

Fatal: setgid(5000(vmail) from userdb lookup) failed with euid=8(mail), gid=12(mail), egid=12(mail): Operation not permitted (This binary should probably be called with process group set to 5000(vmail) instead of 12(mail))

dovecot deliver agent defined in sendmail.cf with U=vmail:vmail

Mdovecot,      P=/usr/libexec/dovecot/dovecot-lda,
           F=l59DFMPhnu,
           S=EnvFromL/HdrFromL, R=EnvToL/HdrToL,
           M=51200000,
           U=vmail:vmail,
           T=DNS/RFC822/X-Unix,
           A=/usr/libexec/dovecot/dovecot-lda -d $u

dovecot-lda has same owner and group

-rwxr-x--- 1 vmail vmail 28512 апр.   5  2013 /usr/libexec/dovecot/dovecot-lda

If i use system user mail instead vmail everything starts working fine.
But this config seems to me less secure and i want use user vmail with uid > 100 instead of user mail.

So mail delivery fails. I appreciate any help solving this problem.

Best Answer

  1. Skip reading if you are not determined :-)

  2. Make vmail special to sendmail (no DNS lookups for destination)

    LOCAL_CONFIG
CPvmail

  3. Use FEATURE(ldap_routing) to select mailHost not mailRoutingAddress

  4. Use FEATURE(mailertable) to select delivery method (mailer)

    mailertable

    vmail  dovecot:dummy

  5. Do not make dovecot the local mailer - FEATURE(local_procmail,...)

  6. In dovecot mailer definition use xSMTP rules not xL (local) rules

    http://wiki2.dovecot.org/LDA/Sendmail

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