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QuantumMechanic
Asked: 2012-07-21 20:34:24 +0800 CST

Can't get SASL auxprop/sasldb working with postfix/Ubuntu 12.04

  • 772

I have an Ubuntu 8.04LTS system running Postfix 2.5.1. On that system SMTP AUTH runs fine. The contents of /etc/postfix/sasl/smtpd.conf are:

pwcheck_method: auxprop
auxprop_plugin: sasldb
mech_list: PLAIN

The SASL-related properties are:

smtpd_sasl_type = cyrus
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = smtpd
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
smtpd_sasl_local_domain = $myhostname

When I do sudo sasldblistusers2 I get:

[email protected]: userPassword

Like I said, that all works fine on the 8.04LTS system.

However, I am trying to migrate this over to an Ubuntu 12.04LTS system running Postfix 2.9.3 and I just cannot get it to work. I'm doing everything the same, but postfix gives authentication failures every time.

It's not the /etc/sasldb2 file. I've tried bringing over the file from the old system and that doesn't work. And I've created a new file using:

saslpasswd2 -c -u mail.mydomain.com authusername

and that doesn't work, though it WILL work on the old system if I copy it to the old system, which is how I know there's nothing wrong with the file.

Similarly, I know postfix is seeing the smtpd.conf file. If I add more mechanisms to the mech_list line of the file, I see those extra mechanisms being advertised when I connect to the smtpd daemon. And when I remove them they go away again. So /etc/postfix/sasl/smtpd.conf is clearly getting used.

I am testing both by using an actual mail client and by manually talking to the server after generating a token with this:

perl -MMIME::Base64 -e 'print encode_base64("\000authusername\000thePassword");'

then:

openssl s_client -quiet -starttls smtp -connect the.newsystem.com:587

The resulting conversation is:

250 DSN
EHLO example.com
250-the.newsystem.com
250-PIPELINING
250-SIZE 20971520
250-ETRN
250-AUTH PLAIN
250-AUTH=PLAIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
AUTH PLAIN theBase64EncodedToken
535 5.7.8 Error: authentication failed: authentication failure

But if I instead connect to the.oldsystem.com:587 and do the same thing, I get:

235 2.7.0 Authentication successful

The output of saslfinger on the new machine is:

# sudoh saslfinger -s
saslfinger - postfix Cyrus sasl configuration Sat Jul 21 00:24:24 EDT 2012
version: 1.0.4
mode: server-side SMTP AUTH

-- basics --
Postfix: 2.9.3
System: Ubuntu 12.04 LTS \n \l

-- smtpd is linked to --
        libsasl2.so.2 => /usr/lib/i386-linux-gnu/libsasl2.so.2 (0xb76c5000)


-- active SMTP AUTH and TLS parameters for smtpd --
broken_sasl_auth_clients = yes
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_path = smtpd
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = cyrus
smtpd_tls_CAfile = /etc/ssl/certs/MyCA.pem
smtpd_tls_auth_only = yes
smtpd_tls_cert_file = /etc/postfix/ssl/server.crt
smtpd_tls_key_file = /etc/postfix/ssl/server.key
smtpd_tls_loglevel = 1
smtpd_tls_security_level = may
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_tls_session_cache_timeout = 3600s


-- listing of /usr/lib/sasl2 --
total 16
drwxr-xr-x  2 root root 4096 Jul 20 23:00 .
drwxr-xr-x 67 root root 8192 Jul 20 21:25 ..
-rw-r--r--  1 root root    1 May  4 00:17 berkeley_db.txt

-- listing of /etc/postfix/sasl --
total 20
drwxr-xr-x 2 root root 4096 Jul 20 21:29 .
drwxr-xr-x 5 root root 4096 Jul 20 23:58 ..
-rw-r--r-- 1 root root   64 Jul 20 21:29 smtpd.conf



-- content of /etc/postfix/sasl/smtpd.conf --
pwcheck_method: auxprop
auxprop_plugin: sasldb
mech_list: PLAIN

-- content of /etc/postfix/sasl/smtpd.conf --
pwcheck_method: auxprop
auxprop_plugin: sasldb
mech_list: PLAIN


-- active services in /etc/postfix/master.cf --
# service type  private unpriv  chroot  wakeup  maxproc command + args
#               (yes)   (yes)   (yes)   (never) (100)
smtp      inet  n       -       -       -       -       smtpd
submission inet n       -       -       -       -       smtpd
  -o syslog_name=postfix/submission
  -o smtpd_tls_security_level=encrypt
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
  -o milter_macro_daemon_name=ORIGINATING

[snipping the rest of the services]

-- mechanisms on localhost --

-- end of saslfinger output --

What could I be missing/doing wrong? As far as I've been able to tell, all the config is the same, yet it will not work on the new system.

ubuntu

3 Answers

  1. Best Answer

    The giveaway is here:

    -- active services in /etc/postfix/master.cf --
# service type  private unpriv  chroot  wakeup  maxproc command + args
#               (yes)   (yes)   (yes)   (never) (100)
smtp      inet  n       -       -       -       -       smtpd
submission inet n       -       -       -       -       smtpd

    The smtpd process on the submission port is running in chroot mode (since there is a - in that column which means the default (which is yes) applies and so can't see /etc/sasldb2.

    When I copied /etc/sasldb2 to /var/spool/postfix/etc authentication started working fine.

    • 16

  2. chroot is defnitely the reason, however for my case, copying to /var/spool/postfix/etc did not work.

    So I just got rid of chroot and that works for me.

    n order to do that you will need to edit /etc/postfix/master.cf locate the following line:

    smtp      inet  n       -       -       -       -       smtpd

    and modify it as follows:

    smtp      inet  n       -       n       -       -       smtpd
    • 5

  3. Another way to synchronize the sasldb2 file to postfix's default chroot jail is to add a hard link to it: 

    ln /etc/sasldb2 /var/spool/postfix/etc/

    Note that a symlink wont work because symlinks cant be accessed from inside the jail but hard links can. This has the advantage over simply copying the file because future new users and password changes will be automatically synced without even a postfix reload.

    • 4