Re: imapc and masteruser

[Computerisms Corporation]

Hi Sami


I followed this before, and it seemed the solution was to set

imapc_password = %w

However, dovecot will not start with this configuration.

In Sven's email, he places the imapc_password = %w as a default_field in the 
userdb on the primary instance.  If I remove the default field, I get the 
invalid credentials reported as above.  However, I still think this is correct 
way to pass %w, because if I remove 'imapc_user = authapps' from the global 
config *and*  'imapc_password = %w' from the default_fields in the userdb, the 
logs on the shared instance show that the user password is not being passed in 
the imapc login:


2017-09-28 12:57:10.409884500 Sep 28 12:57:10 auth: Debug: 
static(bob.test,192.168.120.70,): lookup
2017-09-28 12:57:10.409903500 Sep 28 12:57:10 auth: Debug: 
static(bob.test,192.168.120.70,): username changed bob.test 
-> authapps
2017-09-28 12:57:10.409905500 Sep 28 12:57:10 auth: Info: 
static(authapps,192.168.120.70,): No password returned (and 
no nopassword)
2017-09-28 12:57:12.412437500 Sep 28 12:57:12 auth: Debug: client passdb out: 
FAIL  11  user=authapps   original_user=bob.test


Now this starts to be a bit complex. Not sure if you can get this working by 
returning imapc_password = %w from the first passdb. Atleast if it works it 
will only work with PLAIN auth scheme.
What I would do here is to just trust that the user is already authenticated 
with the first ldap passdb in the primary server and then switch the imapc 
connection to both master user and master password.

So just put imapc_password=masterpassword in dovecot.conf of the primary server 
and on secondary server modify ldap config not to fetch the user password but 
always return password=masterpassword.


It took me a while to wrap my head around what you are saying here, but 
once I got it I find it a simple, elegant and absolutely brilliant solution.


In thinking about it, it occurred to me I could maybe do the same 
without even doing an ldap look up, so I changed the userdb/passdb 
stanzas on the shared instance like so:


userdb {
  args = uid=vmail gid=vmail home=/CTFN/SharedMailboxes/CTFN/
  driver = static
}
passdb {
  args = user=%u password=XXX
  driver = static
  master = yes
}
passdb {
  driver = static
}


Where the password is the value set for imapc_password on the primary 
instance.


The logs now show on the shared server that the user is authapps, and it 
has the correct effective uid/gid/home values, and the master user and 
the acl username is that of the user logging into the primary instance.


So looks like this will work!

Thank you, Sami, a bottle of Canada's finest is at your disposal...





and maybe protect the authentication scheme with allow_nets=127.0.0.1 from 
external abuse

Sami

Re: imapc and masteruser

[Sami Ketola]

> On 28 Sep 2017, at 23.08, Computerisms Corporation  
> wrote:
> 
> Hi Sami,
> 
> Thank you for your reply.
>> yes you do need to define imapc_user if you want to switch user and master 
>> user around for imapc. like:
>> imapc_user = authapps
>> imapc_master_user = %u
>> without imapc_user dovecot would login to the secondary server like A 
>> bob.test*bob.test password
> 
> When I add the 'imapc_user = authapps' option to the primary instance running 
> on port 993, it passes the imapc_password as the password for the master 
> user.  here is what the logs on the shared instance show when I log into the 
> primary instance:
> 
> 2017-09-28 12:47:35.361064500 Sep 28 12:47:35 auth: Debug: 
> ldap(bob.test,192.168.120.70,master,): Master user lookup 
> for login: authapps
> 2017-09-28 12:47:35.364892500 Sep 28 12:47:35 auth: Info: 
> ldap(bob.test,192.168.120.70,master,): invalid credentials 
> (given password: X)
> 2017-09-28 12:47:37.367173500 Sep 28 12:47:37 auth: Debug: client passdb out: 
> FAIL2   user=bob.test
> 
> 
> The given password in the logs is the password supplied as imapc_password.
> 
> if I change the imapc_password to be that of the bob.test user, the imapc 
> login does succeed with bob.test as the master user.
> 
> I followed this before, and it seemed the solution was to set
> 
> imapc_password = %w
> 
> However, dovecot will not start with this configuration.
> 
> In Sven's email, he places the imapc_password = %w as a default_field in the 
> userdb on the primary instance.  If I remove the default field, I get the 
> invalid credentials reported as above.  However, I still think this is 
> correct way to pass %w, because if I remove 'imapc_user = authapps' from the 
> global config *and*  'imapc_password = %w' from the default_fields in the 
> userdb, the logs on the shared instance show that the user password is not 
> being passed in the imapc login:
> 
> 
> 2017-09-28 12:57:10.409884500 Sep 28 12:57:10 auth: Debug: 
> static(bob.test,192.168.120.70,): lookup
> 2017-09-28 12:57:10.409903500 Sep 28 12:57:10 auth: Debug: 
> static(bob.test,192.168.120.70,): username changed bob.test 
> -> authapps
> 2017-09-28 12:57:10.409905500 Sep 28 12:57:10 auth: Info: 
> static(authapps,192.168.120.70,): No password returned (and 
> no nopassword)
> 2017-09-28 12:57:12.412437500 Sep 28 12:57:12 auth: Debug: client passdb out: 
> FAIL11  user=authapps   original_user=bob.test
> 
> 
> so maybe I am not passing the %w in the correct spot?
> 
> truly appreciate you taking a look at this, thank you.


Now this starts to be a bit complex. Not sure if you can get this working by 
returning imapc_password = %w from the first passdb. Atleast if it works it 
will only work with PLAIN auth scheme.
What I would do here is to just trust that the user is already authenticated 
with the first ldap passdb in the primary server and then switch the imapc 
connection to both master user and master password.

So just put imapc_password=masterpassword in dovecot.conf of the primary server 
and on secondary server modify ldap config not to fetch the user password but 
always return password=masterpassword.

and maybe protect the authentication scheme with allow_nets=127.0.0.1 from 
external abuse

Sami

Re: imapc and masteruser

[Computerisms Corporation]

Hi Sami,

Thank you for your reply.

yes you do need to define imapc_user if you want to switch user and master user 
around for imapc. like:

imapc_user = authapps
imapc_master_user = %u

without imapc_user dovecot would login to the secondary server like A 
bob.test*bob.test password


When I add the 'imapc_user = authapps' option to the primary instance 
running on port 993, it passes the imapc_password as the password for 
the master user.  here is what the logs on the shared instance show when 
I log into the primary instance:


2017-09-28 12:47:35.361064500 Sep 28 12:47:35 auth: Debug: 
ldap(bob.test,192.168.120.70,master,): Master user 
lookup for login: authapps
2017-09-28 12:47:35.364892500 Sep 28 12:47:35 auth: Info: 
ldap(bob.test,192.168.120.70,master,): invalid 
credentials (given password: X)
2017-09-28 12:47:37.367173500 Sep 28 12:47:37 auth: Debug: client passdb 
out: FAIL	2	user=bob.test



The given password in the logs is the password supplied as imapc_password.

if I change the imapc_password to be that of the bob.test user, the 
imapc login does succeed with bob.test as the master user.


I followed this before, and it seemed the solution was to set

imapc_password = %w

However, dovecot will not start with this configuration.

In Sven's email, he places the imapc_password = %w as a default_field in 
the userdb on the primary instance.  If I remove the default field, I 
get the invalid credentials reported as above.  However, I still think 
this is correct way to pass %w, because if I remove 'imapc_user = 
authapps' from the global config *and*  'imapc_password = %w' from the 
default_fields in the userdb, the logs on the shared instance show that 
the user password is not being passed in the imapc login:



2017-09-28 12:57:10.409884500 Sep 28 12:57:10 auth: Debug: 
static(bob.test,192.168.120.70,): lookup
2017-09-28 12:57:10.409903500 Sep 28 12:57:10 auth: Debug: 
static(bob.test,192.168.120.70,): username changed 
bob.test -> authapps
2017-09-28 12:57:10.409905500 Sep 28 12:57:10 auth: Info: 
static(authapps,192.168.120.70,): No password returned 
(and no nopassword)
2017-09-28 12:57:12.412437500 Sep 28 12:57:12 auth: Debug: client passdb 
out: FAIL	11	user=authapps	original_user=bob.test



so maybe I am not passing the %w in the correct spot?

truly appreciate you taking a look at this, thank you.


passdb {
  args = user=authapps password=XX
  driver = static
}


This is probably correct except that now user authapps can also login directly 
with password XX without master user login.
Which is probably OK as long as the password is kept secret


Once I get the imapc master user sorted out, I will play with the config 
to see what I can trim, but as of now, dropping just the password, or 
the entire args line, also causes the imapc login to fail...


truly appreciate you taking a look at this, thank you.



Sami

Re: imapc and masteruser

[Sami Ketola]

> On 28 Sep 2017, at 20.50, Computerisms Corporation  
> wrote:
> 
> Hi,
> 
> My end goal is to set up shared mailboxes on a cluster as per:
> 
> https://wiki.dovecot.org/SharedMailboxes/ClusterSetup
> 
> I was having very little luck with it, so I had been trying to break down 
> into pieces and get individual components working.  So I have things setup on 
> a single server, with a working dovecot instance.  I have no director or any 
> thing else running yet, and I am just trying to get the imapc portion of 
> things working.  Eventually I came across a post from Sven Hartge:
> 
> https://www.dovecot.org/list/dovecot/2012-November/087046.html
> 
> This is from several years ago, but I set up a separate dovecot instance on 
> port 9993 specifically to run the shared folders as he describes, and copied 
> his configuration suggestions pretty much verbatim.  The only signficant 
> difference is that I needed to not configure the imapc_user as he had done, 
> and instead as the wiki suggests remove that config option entirely.  With 
> this, the imapc connection is being made from the primary instance on port 
> 993 to the shared instance on port 9993.

yes you do need to define imapc_user if you want to switch user and master user 
around for imapc. like:

imapc_user = authapps
imapc_master_user = %u

without imapc_user dovecot would login to the secondary server like A 
bob.test*bob.test password


> 
> SHARED SERVER ON PORT 9993
> 
> passdb {
>  args = /usr/local/etc/dovecot/dovecot-ldap.conf.ext
>  driver = ldap
>  master = yes
> }
> passdb {
>  args = user=authapps password=XX
>  driver = static
> }

This is probably correct except that now user authapps can also login directly 
with password XX without master user login.
Which is probably OK as long as the password is kept secret

Sami