diff -upk.orig postfix-2.2.4.orig/proto/postconf.proto postfix-2.2.4/proto/postconf.proto
--- postfix-2.2.4.orig/proto/postconf.proto	2005-06-23 12:37:33 +0000
+++ postfix-2.2.4/proto/postconf.proto	2005-06-23 12:51:25 +0000
@@ -2345,6 +2345,11 @@ mailbox_command = /some/where/maildrop -
         -f "$SENDER" "$EXTENSION"
 </pre>
 
+%PARAM mailbox_unpriv_delivery yes
+
+<p> If enabled, then local(8) will not apply root privileges
+for mailbox delivery.  </p>
+
 %PARAM mailbox_size_limit 51200000
 
 <p> The maximal size of any local(8) individual mailbox or maildir
diff -upk.orig postfix-2.2.4.orig/src/global/mail_params.h postfix-2.2.4/src/global/mail_params.h
--- postfix-2.2.4.orig/src/global/mail_params.h	2005-06-23 12:49:30 +0000
+++ postfix-2.2.4/src/global/mail_params.h	2005-06-23 12:51:25 +0000
@@ -470,6 +470,10 @@ extern char *var_mail_spool_dir;
 #define DEF_HOME_MAILBOX	""
 extern char *var_home_mailbox;
 
+#define VAR_MAILBOX_UNPRIV_DELIVERY	"mailbox_unpriv_delivery"
+#define DEF_MAILBOX_UNPRIV_DELIVERY	1
+bool	var_mailbox_unpriv_delivery;
+
 #define VAR_MAILBOX_COMMAND	"mailbox_command"
 #define DEF_MAILBOX_COMMAND	""
 extern char *var_mailbox_command;
diff -upk.orig postfix-2.2.4.orig/src/local/local.c postfix-2.2.4/src/local/local.c
--- postfix-2.2.4.orig/src/local/local.c	2005-06-23 12:37:33 +0000
+++ postfix-2.2.4/src/local/local.c	2005-06-23 12:51:25 +0000
@@ -374,6 +374,9 @@
 /* .IP "\fBmailbox_command (empty)\fR"
 /*	Optional external command that the \fBlocal\fR(8) delivery agent should
 /*	use for mailbox delivery.
+/* .IP "\fBmailbox_unpriv_delivery (yes)\fR"
+/*	If enabled, then local(8) will not apply root privileges
+/*	for mailbox delivery.
 /* .IP "\fBhome_mailbox (empty)\fR"
 /*	Optional pathname of a mailbox file relative to a \fBlocal\fR(8) user's
 /*	home directory.
@@ -576,6 +579,7 @@ char   *var_allow_files;
 char   *var_alias_maps;
 int     var_dup_filter_limit;
 char   *var_home_mailbox;
+bool    var_mailbox_unpriv_delivery;
 char   *var_mailbox_command;
 char   *var_mailbox_cmd_maps;
 char   *var_rcpt_fdelim;
@@ -835,6 +839,7 @@ int     main(int argc, char **argv)
 	VAR_EXP_OWN_ALIAS, DEF_EXP_OWN_ALIAS, &var_exp_own_alias,
 	VAR_STAT_HOME_DIR, DEF_STAT_HOME_DIR, &var_stat_home_dir,
 	VAR_MAILTOOL_COMPAT, DEF_MAILTOOL_COMPAT, &var_mailtool_compat,
+	VAR_MAILBOX_UNPRIV_DELIVERY, DEF_MAILBOX_UNPRIV_DELIVERY, &var_mailbox_unpriv_delivery,
 	0,
     };
 
diff -upk.orig postfix-2.2.4.orig/src/local/mailbox.c postfix-2.2.4/src/local/mailbox.c
--- postfix-2.2.4.orig/src/local/mailbox.c	2002-11-16 23:44:57 +0000
+++ postfix-2.2.4/src/local/mailbox.c	2005-03-02 22:33:07 +0000
@@ -149,7 +149,8 @@ static int deliver_mailbox_file(LOCAL_ST
      * world-writable, deliver as the recipient; if the spool directory is
      * group-writable, use the recipient user id and the mail spool group id.
      * 
-     * Otherwise, use root privileges and chown the mailbox.
+     * Otherwise, if var_mailbox_unpriv_delivery is set, then deliver
+     * as the recipient, else use root privileges and chown the mailbox.
      */
     if (spool_dir == 0
 	|| stat(spool_dir, &st) < 0
@@ -160,8 +161,8 @@ static int deliver_mailbox_file(LOCAL_ST
 	spool_uid = usr_attr.uid;
 	spool_gid = st.st_gid;
     } else {
-	spool_uid = 0;
-	spool_gid = 0;
+	spool_uid = var_mailbox_unpriv_delivery ? usr_attr.uid : 0;
+	spool_gid = var_mailbox_unpriv_delivery ? usr_attr.gid : 0;
     }
     if (spool_uid == usr_attr.uid) {
 	chown_uid = -1;