From 11f6fa6e1c39dcc27fb7da0d77ac11589ddf9139 Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Sun, 31 May 2015 16:48:45 +0100
Subject: [PATCH] Give up on checking claimed sender addresses.

I'm told that it's more hassle than its worth.  I can track down
forgeries sufficiently well by staring at Received headers and staring
at logs.
---
 base.m4   | 28 ----------------------------
 config.m4 |  1 -
 lists.m4  |  8 --------
 local.m4  | 21 ---------------------
 4 files changed, 58 deletions(-)

diff --git a/base.m4 b/base.m4
index d43a6f0..22f6852 100644
--- a/base.m4
+++ b/base.m4
@@ -301,34 +301,6 @@ mail_check_auth:
 	deny	 message = Sender not authenticated
 		 condition = ${if !def:acl_c_user}
 
-	## Make sure that the local part is one that the authenticated sender
-	## is allowed to claim.
-	deny	 message = Sender address forbidden to calling user
-		!condition = \
-			${if exists {CONF_sysconf_dir/auth-sender.conf} \
-			     {${lookup {$acl_c_user} \
-				       lsearch \
-				       {CONF_sysconf_dir/auth-sender.conf} \
-				       {${if match_address \
-					     {$sender_address} \
-					     {+value}}} \
-				       {false}}}}
-		!condition = ${LOOKUP_DOMAIN($sender_address_domain,
-			       {${if and {{match_local_part \
-					    {$acl_c_user} \
-					    {+dom_users}} \
-					  {match_local_part \
-					    {$sender_address_local_part} \
-					    {+dom_locals}}}}},
-			       {${if and {{match_local_part \
-					    {$sender_address_local_part} \
-					    {+user_extaddr}} \
-					  {or {{eq {$sender_address_domain} \
-						   {}} \
-					       {match_domain \
-						 {$sender_address_domain} \
-						 {+public}}}}}}})}
-
 	## All done.
 	accept
 
diff --git a/config.m4 b/config.m4
index ee20d3a..e440d28 100644
--- a/config.m4
+++ b/config.m4
@@ -67,7 +67,6 @@ DEFCONF(ca_dir, /etc/ca)
 
 ## User address suffix handling.
 DEFCONF(user_suffix_list, +* : -*)
-DEFCONF(user_extaddr_regexp, $acl_c_user([-+@]|\$))
 DEFCONF(user_extaddr_fixup, ${sg {$local_part_suffix}{^[-+]}{}})
 
 ## Other hosts allowed to relay mail through us.
diff --git a/lists.m4 b/lists.m4
index 93f3b2a..11e1baa 100644
--- a/lists.m4
+++ b/lists.m4
@@ -49,14 +49,6 @@ domainlist thishost = @ : @[] : \
 	      {$item.$qualify_domain}}
 domainlist public = +thishost : CONF_sysdomains
 
-## Some magic lists used because `match_local_parts' and friends don't expand
-## their right-hand sides.
-localpartlist dom_users = ${expand:KV(users, {$value}{*})}
-localpartlist dom_locals = ${expand:KV(locals, {$value}{+user_extaddr})}
-localpartlist user_extaddr = ^CONF_user_extaddr_regexp
-addresslist user_extaddr = ^CONF_user_extaddr_regexp
-addresslist value = $value
-
 ## All of the `standard' local parts which ought to be provided by a domain.
 localpartlist required = postmaster : abuse
 
diff --git a/local.m4 b/local.m4
index c403876..65939a2 100644
--- a/local.m4
+++ b/local.m4
@@ -37,27 +37,6 @@ m4_define(<:FILTER_LOCALUSER:>,
 SECTION(global, priv)m4_dnl
 local_from_suffix = CONF_user_suffix_list
 
-SECTION(global, process)m4_dnl
-## Restrict users to plausible envelope sender addresses.  This is
-## surprisingly fiddly.  What I actually want to say is that the local part
-## must match ^$sender_ident(\$|-) and the domain part must match an
-## appropriate domain; but writing a conjunction is rather tricky.  And so we
-## must burn some addresslist variables.
-addresslist wrong_local = ! +user_extaddr
-addresslist wrong_domain = ! *@+public
-addresslist wrong_address = +wrong_local : +wrong_domain
-untrusted_set_sender = : \
-	${if exists {CONF_sysconf_dir/auth-sender.conf} \
-	     {${lookup {$sender_ident} \
-		       lsearch {CONF_sysconf_dir/auth-sender.conf} \
-		       {$value}}}} : \
-	${LOOKUP_DOMAIN($sender_address_domain,
-		{${if and {{match_local_part {$sender_ident} {+dom_users}} \
-			   {match_local_part {$sender_address_local_part} \
-					     {+dom_locals}}} \
-		      {*}}})} : \
-	! +wrong_address
-
 ###--------------------------------------------------------------------------
 ### Forwarding and redirection for incoming mail.
 
-- 
2.11.0