[Dovecot] Hierarchy separator usage -- and a bijou bug? (was: Prayer, Maildir and Folders whose names begin with ".")

[Mike Brudenell]

Greetings -

> On 9 Mar 2007, at 19:40, Timo Sirainen wrote:
>
> I don't see any other way of doing this. Except possibly to give
> "invalid mailbox name" errors, or maybe even change the dot  
> silently to
> some other character. All of these options kind of suck.

We've been discussing this problem here and feel that for our users  
asking for a folder "M.Brudenell" but being given folder "M"  
containing folder "Brudenell" is going to be too unexpected.

Instead we'd like to either reject attempts to create a folder  
containing ".", or else silently change the "." to another single  
character (eg, "_").  We haven't decided which yet, but probably the  
former.

I've been trying to find my way around the Dovecot source (a new  
package is _such_ an adventure! :-) and I *think* the place for us to  
bolt such a check in is here:

     File:       src/imap/commands-util.c
     Function:   client_verify_mailbox_name()

Currently this contains various checks including one like this:

     /* make sure two hierarchy separators aren't next to each others */
     for (p = mailbox+1; *p != '\0'; p++) {
             if (p[0] == sep && p[-1] == sep) {
                     client_send_tagline(cmd, "NO Invalid mailbox  
name.");
                     return FALSE;
             }
     }

I was thinking of preceding this with something along the lines of  
this (UNTESTED) code fragment:

     /* if the separator isn't '.' then don't allow '.' in folder  
names */
     if (sep != '.') {
         for (p = mailbox; *p != '\0'; p++) {
                 if (p[0] == '.') {
                         client_send_tagline(cmd, "NO Full-stop not  
allowed in mailbox name.");
                         return FALSE;
                 }
         }
     }

Does something like this look OK?

And should it be sufficient?  (ie, is this the only place I would  
need to insert such a test, or are there other files/functions that  
would need it too?)

===================================

By the way...

Timo:  I may have spotted another instance of a mailbox name being  
returned using the wrong hierarchy separator character (in Dovecot  
1.0rc24 with separator set to "/").  Here:

a01 login pmb1 secretpassword
a01 OK Logged in.
a02 select a//b          <========================== Asked with //
a02 NO Mailbox doesn't exist: a..b     <============ Reply with ..
a03 select a..b
a03 NO Mailbox doesn't exist: a..b
a04 create a..b
a04 NO Invalid mailbox name.
a05 create a//b
a05 NO Invalid mailbox name.
a06 logout
* BYE Logging out
a06 OK Logout completed.

And also...

I'm confused how client_verify_mailbox_name() is detecting two or  
more of either "." or "/" as the code looks to only check one  
separator character (obtained from mail_storage_get_hierarchy_sep 
(storage))

Or is this returning the separator character maildir is using (".")  
and not the hierarchy separator which we have changed in the Dovecot  
configuration file to "/"?  If so then my code fragment isn't going  
to work, as the Maildir filestore separator will continue to be "." :-(

Help!  I'm confused now!

Cheers,
Mike B-)

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