X-Git-Url: https://git.distorted.org.uk/~mdw/exim-config/blobdiff_plain/d70f6d53afe0d485268ebc22ba37df2dd671251f..87afdfcd0186f0f455034c92257b46a015174335:/base.m4

diff --git a/base.m4 b/base.m4
index 0827835..e74803d 100644
--- a/base.m4
+++ b/base.m4
@@ -60,9 +60,7 @@ gecos_pattern = ([^,:]*)
 SECTION(global, incoming)m4_dnl
 received_header_text = Received: \
 	${if def:sender_rcvhost \
-	     {from $sender_rcvhost\
-	      ${if def:sender_helo_name \
-		   { (helo=$sender_helo_name)}}\n\t} \
+	     {from $sender_rcvhost\n\t} \
 	     {${if def:sender_ident \
 		   {from ${quote_local_part:$sender_ident} }}}}\
 	by $primary_hostname \
@@ -90,6 +88,18 @@ qualify_domain = CONF_master_domain
 SECTION(global, bounce)m4_dnl
 delay_warning = 1h : 24h : 2d
 
+SECTION(global, tls)m4_dnl
+tls_certificate = CONF_sysconf_dir/server.cert
+tls_privatekey = CONF_sysconf_dir/server.key
+tls_advertise_hosts = ${if exists {CONF_sysconf_dir/server.key} {*}{}}
+tls_dhparam = CONF_ca_dir/dh-param-2048.pem
+tls_require_ciphers = ${if or {{={$received_port}{CONF_submission_port}} \
+			       {match_ip {$sender_host_address}{+trusted}}} \
+			   {CONF_good_ciphers} \
+			   {CONF_acceptable_ciphers}}
+tls_verify_certificates = CONF_ca_dir/ca.cert
+tls_verify_hosts = ${if eq{$acl_c_mode}{submission} {} {+allnets}}
+
 DIVERT(null)
 ###--------------------------------------------------------------------------
 ### Access control lists.
@@ -107,19 +117,34 @@ helo:
 	## and we should only care about the most recent one.
 	warn	 set acl_c_helo_warning = false
 		!condition = \
+			${if and {{match_ip {$sender_host_address} \
+					    {<; 127.0.0.0/8 ; ::1}} \
+				  {match_domain {$sender_helo_name} \
+						{localhost : +thishost}}}}
+		!condition = \
 			${if exists {CONF_sysconf_dir/helo.conf} \
 			     {${lookup {$sender_helo_name} \
 				       partial0-lsearch \
 				       {CONF_sysconf_dir/helo.conf} \
 				       {${if match_ip \
 					     {$sender_host_address} \
-					     {$value}}}}}}
+					     {<; $value}}}}}}
 		!verify = helo
 		 set acl_c_helo_warning = true
 
 	accept
 
 SECTION(global, acl)m4_dnl
+acl_not_smtp_start = not_smtp_start
+SECTION(acl, misc)m4_dnl
+not_smtp_start:
+	## Record the user's name.
+	warn	 set acl_c_user = $sender_ident
+
+	## Done.
+	accept
+
+SECTION(global, acl)m4_dnl
 acl_smtp_mail = mail
 SECTION(acl, mail)m4_dnl
 mail:
@@ -130,7 +155,7 @@ mail:
 		 add_header = :after_received:X-Distorted-Warning: \
 			BADHELO \
 			Client's HELO doesn't match its IP address.\n\t\
-			HELO name=$sender_helo_name, \
+			helo-name=$sender_helo_name \
 			address=$sender_host_address
 
 	## Always allow the empty sender, so that we can receive bounces.
@@ -146,6 +171,15 @@ mail:
 	warn	 condition = ${if eq{$acl_c_mode}{submission}}
 		 control = submission
 
+	## Insist that a local client connect through TLS.
+	deny	 message = Hosts within CONF_master_domain must use TLS
+		!condition = ${if eq{$acl_c_mode}{submission}}
+		 hosts = +allnets
+		!encrypted = *
+
+	## Check that a submitted message's sender address is allowable.
+	require	 acl = mail_check_auth
+
 SECTION(acl, mail-tail)m4_dnl
 	## And we're done.
 	accept
@@ -163,7 +197,7 @@ SECTION(acl, connect-tail)m4_dnl
 
 check_submission:
 	## See whether this message needs hacking on.
-	accept	!hosts = +localnet
+	accept	!hosts = +thishost
 		!condition = ${if ={$received_port}{CONF_submission_port}}
 		 set acl_c_mode = relay
 
@@ -180,16 +214,35 @@ rcpt:
 
 	## Reject if the client isn't allowed to relay and the recipient
 	## isn't in one of our known domains.
-	deny	 message = Relaying not permitted
-		!hosts = CONF_relay_clients
-		!authenticated = *
-		!domains = +known
+	require	 message = Relaying not permitted
+		 acl = check_relay
 
 	## Ensure that the recipient is routable.
 	require	 message = Invalid recipient \
 			($recipient_verify_failure; $acl_verify_message)
 		 verify = recipient
 
+SECTION(acl, misc)m4_dnl
+check_relay:
+	## Accept either if the client is allowed to relay through us, or if
+	## we're the correct place to send this mail.
+
+	## Known clients and authenticated users are OK.
+	accept	  hosts = CONF_relay_clients
+	accept	  authenticated = *
+
+	## Known domains are OK.
+	accept	  domains = +public
+
+	## Finally, domains in our table are OK, unless they say they aren't.
+	accept	  domains = \
+		${if exists{CONF_sysconf_dir/domains.conf} \
+		     {partial0-lsearch;	CONF_sysconf_dir/domains.conf}}
+		  condition = DOMKV(service, {$value}{true})
+
+	## Nope, that's not allowed.
+	deny
+
 SECTION(acl, rcpt-tail)m4_dnl
 	## Everything checks out OK: let this one go through.
 	accept
@@ -212,6 +265,60 @@ expn_vrfy:
 
 DIVERT(null)
 ###--------------------------------------------------------------------------
+### Verification of sender address.
+
+SECTION(acl, misc)m4_dnl
+mail_check_auth:
+
+	## If this isn't a submission then it doesn't need checking.
+	accept	 condition = ${if !eq{$acl_c_mode}{submission}}
+
+	## If the caller hasn't formally authenticated, but this is a
+	## loopback connection, then we can trust identd to tell us the right
+	## answer.  So we should stash the right name somewhere consistent.
+	warn	 set acl_c_user = $authenticated_id
+		 hosts = +thishost
+		!authenticated = *
+		 condition = ${if def:sender_ident}
+		 set acl_c_user = $sender_ident
+
+	## User must be authenticated by now.
+	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
+
+DIVERT(null)
+###--------------------------------------------------------------------------
 ### Common options for forwarding routers.
 
 ## We're pretty permissive here.
@@ -242,12 +349,20 @@ m4_define(<:FILTER_VERIFY:>,
 
 ## Transports for redirection filters.
 m4_define(<:FILTER_TRANSPORTS:>,
-	<:verify = false
-	file_transport = mailbox
+	<:file_transport = mailbox
 	directory_transport = maildir
 	pipe_transport = pipe
 	reply_transport = reply:>)
 
+m4_define(<:FILTER_ROUTER:>,
+<:$1_vrf:
+	$2
+	FILTER_VERIFY<::>$3
+$1:
+	$2
+	verify = no
+	FILTER_TRANSPORTS<::>$4:>)
+
 DIVERT(null)
 ###--------------------------------------------------------------------------
 ### Some standard transports.
@@ -258,15 +373,42 @@ m4_define(<:USER_DELIVERY:>,
 	return_path_add = true:>)
 
 SECTION(transports)m4_dnl
-## A standard transport for remote delivery.  Try to do TLS, and don't worry
-## too much if it's not very secure: the alternative is sending in plaintext
-## anyway.
+## A standard transport for remote delivery.  By default, try to do TLS, and
+## don't worry too much if it's not very secure: the alternative is sending
+## in plaintext anyway.  But all of this can be overridden from the
+## `domains.conf' file.  Annoyingly, the `tls_dh_min_bits' setting isn't
+## expanded before use, so we can't set it the obvious way.  Instead, encode
+## it into the transport name.  This is very unpleasant, of course.
 smtp:
 	driver = smtp
 	tls_require_ciphers = CONF_acceptable_ciphers
 	tls_dh_min_bits = 1020
 	tls_tempfail_tryclear = true
 
+m4_define(<:SMTP_TRANS_DHBITS:>,
+	<:driver = smtp
+	hosts_try_auth = *
+	hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
+	hosts_require_auth = \
+		${if bool {DOMKV(require-auth, {$value}{false})} {*}{}}
+	tls_certificate = DOMKV(tls-certificate, {${expand:$value}}fail)
+	tls_privatekey = DOMKV(tls-private-key, {${expand:$value}}fail)
+	tls_verify_certificates = DOMKV(tls-peer-ca, {${expand:$value}}fail)
+	tls_require_ciphers = \
+		DOMKV(tls-ciphers,
+		      {${extract {${expand:$value}} \
+				 { good = CONF_good_ciphers \
+				   any = CONF_acceptable_ciphers } \
+				 {$value} \
+				 {${expand:$value}}}} \
+		      {CONF_acceptable_ciphers})
+	tls_dh_min_bits = $1
+	tls_tempfail_tryclear = true:>)m4_dnl
+smtp_dhbits_1024:
+	SMTP_TRANS_DHBITS(1020)
+smtp_dhbits_2048:
+	SMTP_TRANS_DHBITS(2046)
+
 ## Transport to a local SMTP server; use TLS and perform client
 ## authentication.
 smtp_local: