dovecot - Sep 2006 - rc7 bug? [Was: deliver LDA and INBOX location] (fwd)

Anyone had any thoughts on the item below?

If the problem is with my config, I'd like to be guided towards how I
might resolve it.

If it is a bug in rc7, it would be good to fix it, and I'd be happy to
beta-test.

-- 

:  David Lee                                I.T. Service          :
:  Senior Systems Programmer                Computer Centre       :
:                                           Durham University     :
:  http://www.dur.ac.uk/t.d.lee/            South Road            :
:                                           Durham DH1 3LE        :
:  Phone: +44 191 334 2752                  U.K.                  :

---------- Forwarded message ----------
Date: Fri, 1 Sep 2006 10:22:20 +0100 (BST)
From: David Lee <t.d.lee at durham.ac.uk>
To: dovecot at dovecot.org
Subject: Re: [Dovecot] rc7 bug? [Was: deliver LDA and INBOX location]

On Thu, 31 Aug 2006, David Lee wrote:
> [...]
> We have a well-established different convention which subdivides this,
> based on the last two digits of the uid:
"/var/spool/mail/12/fred" (for
> fred's uid as something ending "[...]12").  This is working
nicely with
> dovecot, using the new rc7 functionality:
>   default_mail_env = mbox:%h:INBOX=/var/spool/mail/%-2.02i/%u:[...]
>
> I am now trying to get sendmail to use dovecot's "deliver" as
the LDA,
> [...] The main problem is that, according to the log file, the delivery
> attempt is being made to an INBOX "/var/spool/mail//fred".  That
is, it
> seems to be ignoring the "default_mail_env" setting.
>
> Have I missed something in the wiki, or is this a bug of some sort?
I have looked deeper at my problem (abov).  It seems to be a bug in rc7,
and probably an "always been there" bug.

I sprinked a few "i_info(...)" diagnostics into "deliver.c"
where it does
'getenv("MAIL")' and
'getenv("DEFAULT_MAIL_ENV")'.  It shows that these
are being successfully read from the 'dovecot.conf' file (good).

But, crucially, it seems that the "%" variable substitution is
incomplete:

   line 483: MAIL [null]
   line 486: MAIL
mbox:%h:INBOX=/var/spool/mail/%-2.02i/%u:INDEX=/var/spool/mail/indexes/%d/%n
   line 492: MAIL
mbox:/home/fred:INBOX=/var/spool/mail//fred:INDEX=/var/spool/mail/indexes//fred

(Aside: The act of inserting the 'i_info' will have knocked the line
numbers adrift by a couple.  But it shows what is (not) happening.)

Note in the "INBOX=..." clause that while "%u" and
"%h" have been
successfully expanded (good), the "%i" variant (UNIX uid) has failed
to
get expanded (bad).

I'm new to dovecot, so am on a steep learning curve and am unfamiliar with
the source code and dovecot's principles.  So it would probably take me
ages to work out a suitable patch, and even then it might be
inappropriate.

But hopefully the above information is sufficient and suitable for someone
(Timo?) to investigate more expertly and fully.

If someone can produce a patch (or hints of what to patch and where) I
would certainly intend to test it and work on it for you.

Hope that helps.  Many thanks in advance.

-- 

:  David Lee                                I.T. Service          :
:  Senior Systems Programmer                Computer Centre       :
:                                           Durham University     :
:  http://www.dur.ac.uk/t.d.lee/            South Road            :
:                                           Durham DH1 3LE        :
:  Phone: +44 191 334 2752                  U.K.                  :

Quoting David Lee <t.d.lee at durham.ac.uk>:
> Anyone had any thoughts on the item below?
I see you have stumbled upon the same problem that prompted me to  
subscribe to this list. I'm running rc7 as well and the deliver LDA is  
ignoring default_mail_env. As a workaround I have now explicitly  
specified each user's home directory in userdb, but it would be  
cleaner if the default could be used.

I didn't look far into the dovecot code, but from what I peeked it  
looks like deliver/auth-client.c bails out at function  
auth_parse_input, if it doesn't receive a home directory from the  
userdb. No provisions there for checking default_mail_env. Or maybe  
I'm looking at the wrong place..

   Tapio

On Tue, 5 Sep 2006, David Lee wrote:
> Anyone had any thoughts on the item below? [see earlier in thread]
>
> If the problem is with my config, I'd like to be guided towards how I
> might resolve it.
>
> If it is a bug in rc7, it would be good to fix it, and I'd be happy to
> beta-test.
BUG in rc7 (and probably from much earlier).

The LDA 'deliver' fails to honour any uid (%i) setting in dovecot.conf.
So delivery and reading happen in different places if 'default_mail_env'
uses a '%i' variant.  Clearly incorrect behaviour.

Attached is a draft of a patch which fixes the problem.  Please could the
patch be reviewed and, in some form, applied?

Thanks.

-- 

:  David Lee                                I.T. Service          :
:  Senior Systems Programmer                Computer Centre       :
:                                           Durham University     :
:  http://www.dur.ac.uk/t.d.lee/            South Road            :
:                                           Durham DH1 3LE        :
:  Phone: +44 191 334 2752                  U.K.                  :
-------------- next part --------------
--- src/deliver/deliver.c.orig	2006-08-10 22:47:56.000000000 +0100
+++ src/deliver/deliver.c	2006-09-05 16:29:32.850394000 +0100
@@ -231,7 +231,7 @@
 }
 
 static const struct var_expand_table *
-get_var_expand_table(const char *user, const char *home)
+get_var_expand_table(const char *user, const char *home, uid_t uid)
 {
 	static struct var_expand_table static_tab[] = {
 		{ 'u', NULL },
@@ -242,6 +242,7 @@
 		{ 'l', NULL },
 		{ 'r', NULL },
 		{ 'p', NULL },
+		{ 'i', NULL },
 		{ '\0', NULL }
 	};
 	struct var_expand_table *tab;
@@ -258,6 +259,7 @@
 	tab[5].value = NULL;
 	tab[6].value = NULL;
 	tab[7].value = my_pid;
+	tab[8].value = dec2str(uid);
 
 	return tab;
 }
@@ -356,7 +358,8 @@
 	struct istream *input;
 	struct mailbox_transaction_context *t;
 	struct mail *mail;
-	uid_t process_euid;
+	struct passwd *upw;
+	uid_t process_euid, uid;
 	int i, ret;
 
 	lib_init();
@@ -432,6 +435,13 @@
 			"destination user parameter (-d user) not given");
 	}
 
+	/* get user's details (in particular, the real uid) */
+	upw = getpwnam(user);
+	if (upw == NULL) {
+		i_fatal("Couldn't lookup user's details (user=%s)", user);
+	}
+	uid = upw->pw_uid;
+
 	config_file_init(config_path);
 	open_logfile(user);
 
@@ -483,7 +493,7 @@
 	if (mail_env == NULL) 
 		mail_env = getenv("DEFAULT_MAIL_ENV");
 	if (mail_env != NULL) {
-		table = get_var_expand_table(destination, getenv("HOME"));
+		table = get_var_expand_table(destination, getenv("HOME"), uid);
 		mail_env = expand_mail_env(mail_env, table);
 	}