X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/exim-config/blobdiff_plain/e12c95862063d5cba833a8db2852916eb5e4e87f..3e7e168cf0a57fea364ad9a913574b383565d9be:/base.m4

diff --git a/base.m4 b/base.m4
index fee3626..e78194a 100644
--- a/base.m4
+++ b/base.m4
@@ -25,6 +25,8 @@
 ### Global settings.
 
 SECTION(global, priv)m4_dnl
+admin_groups = CONF_admin_groups
+trusted_groups = CONF_trusted_groups
 prod_requires_admin = false
 
 SECTION(global, logging)m4_dnl
@@ -38,7 +40,7 @@ syslog_timestamp = false
 
 SECTION(global, daemon)m4_dnl
 local_interfaces = <; CONF_interfaces
-extra_local_interfaces = <; 0.0.0.0 ; ::
+extra_local_interfaces = <; 0.0.0.0 ; ::0
 
 SECTION(global, resource)m4_dnl
 deliver_queue_load_max = 8
@@ -58,20 +60,26 @@ gecos_pattern = ([^,:]*)
 
 SECTION(global, incoming)m4_dnl
 received_header_text = Received: \
-	${if def:sender_rcvhost {from $sender_rcvhost\n\t} \
+	${if def:sender_rcvhost \
+	     {from $sender_rcvhost\n\t} \
 	     {${if def:sender_ident \
-		   {from ${quote_local_part:$sender_ident} }}\
-	      ${if def:sender_helo_name \
-		   {(helo=$sender_helo_name)\n\t}}}}\
+		   {from ${quote_local_part:$sender_ident} }}}}\
 	by $primary_hostname \
+	(Exim $version_number)\
+	${if def:tls_cipher {\n\t} { }}\
 	${if def:received_protocol \
 	     {with $received_protocol \
-	      ${if def:tls_cipher {(cipher=$tls_cipher)\n\t}}}}\
-	(Exim $version_number)\n\t\
+	      ${if def:tls_cipher {(cipher=$tls_cipher)}}}}\n\t\
 	${if def:sender_address \
-	     {(envelope-from <$sender_address>\
+	     {(envelope-from $sender_address\
 	      ${if def:authenticated_id \
-		   {; auth=$authenticated_id}})\n\t}}\
+		   {; auth=${quote_local_part:$authenticated_id}} \
+		   {${if and {{def:authenticated_sender} \
+			      {match_address{$authenticated_sender} \
+					    {*@CONF_master_domain}}} \
+			 {; auth=${quote_local_part:\
+				    ${local_part:\
+				      $authenticated_sender}}}}}})\n\t}}\
 	id $message_exim_id\
 	${if def:received_for {\n\tfor $received_for}}
 
@@ -79,14 +87,32 @@ SECTION(global, smtp)m4_dnl
 smtp_return_error_details = true
 accept_8bitmime = true
 
+SECTION(global, env)m4_dnl
+keep_environment =
+
 SECTION(global, process)m4_dnl
 extract_addresses_remove_arguments = false
 headers_charset = utf-8
 qualify_domain = CONF_master_domain
+untrusted_set_sender = *
+local_from_check = false
+local_sender_retain = true
 
 SECTION(global, bounce)m4_dnl
 delay_warning = 1h : 24h : 2d
 
+SECTION(global, tls)m4_dnl
+tls_certificate = CONF_sysconf_dir/server.certlist
+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.
@@ -96,9 +122,40 @@ SECTION(global, acl)m4_dnl
 acl_smtp_helo = helo
 SECTION(acl, misc)m4_dnl
 helo:
-	require	 message = The other one has bells on
-		 verify = helo
+	## Check that the caller's claimed identity is actually plausible.
+	## This seems like it's a fairly effective filter on spamminess, but
+	## it's too blunt a tool.  Rather than reject, add a warning header.
+	## Only we can't do this the easy way, so save it up for use in MAIL.
+	## Also, we're liable to get a subsequent HELO (e.g., after STARTTLS)
+	## 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}}}}}}
+		!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
+		 set acl_m_user = $sender_ident
+
+	## Done.
 	accept
 
 SECTION(global, acl)m4_dnl
@@ -106,23 +163,60 @@ acl_smtp_mail = mail
 SECTION(acl, mail)m4_dnl
 mail:
 
+	## If we stashed a warning header about HELO from earlier, we should
+	## add it now.  Only don't bother if the client has authenticated
+	## successfully for submission (because we can't expect mobile
+	## clients to be properly set up knowing their names), or it's one of
+	## our own satellites (because they're either properly set up anyway,
+	## or satellites using us as a smarthost).
+	warn	 condition = $acl_c_helo_warning
+		!condition = ${if eq{$acl_c_mode}{submission}}
+		!hosts = +allnets
+		 WARNING_HEADER(BADHELO,
+				<:Client's HELO doesn't match its IP address.\n\t\
+				  helo-name=$sender_helo_name \
+				  address=$sender_host_address:>)
+
 	## Always allow the empty sender, so that we can receive bounces.
 	accept	 senders = :
 
-	## Ensure that the sender is routable.  This is important to prevent
-	## undeliverable bounces.
-	require	 message = Invalid sender; \
-			($sender_verify_failure; $acl_verify_message)
-		 verify = sender
+	## Ensure that the sender looks valid.
+	require	 acl = mail_check_sender
 
 	## If this is directly from a client then hack on it for a while.
 	warn	 condition = ${if eq{$acl_c_mode}{submission}}
-		 control = submission
+		 control = submission/sender_retain
+
+	## 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
 
+SECTION(acl, misc)m4_dnl
+mail_check_sender:
+
+	## See whether there's a special exception for this sender domain.
+	accept	 senders = ${LOOKUP_DOMAIN($sender_address_domain,
+			     {KV(senders, {$value}{})},
+			     {})}
+
+	## Ensure that the sender is routable.  This is important to prevent
+	## undeliverable bounces.
+	require	 message = Invalid sender; \
+			($sender_verify_failure; $acl_verify_message)
+		 verify = sender
+
+	## We're good, then.
+	accept
+
 SECTION(global, acl)m4_dnl
 acl_smtp_connect = connect
 SECTION(acl, connect)m4_dnl
@@ -136,7 +230,7 @@ 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
 
@@ -153,16 +247,35 @@ 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
@@ -178,11 +291,41 @@ SECTION(acl, data-tail)m4_dnl
 SECTION(global, acl)m4_dnl
 acl_smtp_expn = expn_vrfy
 acl_smtp_vrfy = expn_vrfy
-SECTION(acl)m4_dnl
+SECTION(acl, misc)m4_dnl
 expn_vrfy:
 	accept	 hosts = +trusted
 	deny	 message = Suck it and see
 
+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}
+
+	## Set the per-message authentication flag, since we now know that
+	## there's a sensible value.
+	warn	 set acl_m_user = $acl_c_user
+
+	## All done.
+	accept
+
 DIVERT(null)
 ###--------------------------------------------------------------------------
 ### Common options for forwarding routers.
@@ -220,6 +363,31 @@ m4_define(<:FILTER_TRANSPORTS:>,
 	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)
+###--------------------------------------------------------------------------
+### Common routers.
+
+SECTION(routers, alias)m4_dnl
+## Look up the local part in the address map.
+alias:
+	driver = redirect
+	allow_fail = true
+	allow_defer = true
+	user = CONF_filter_user
+	FILTER_TRANSPORTS
+	local_parts = nwildlsearch; CONF_alias_file
+	data = ${expand:$local_part_data}
+SECTION(routers, alias-opts)m4_dnl
+
 DIVERT(null)
 ###--------------------------------------------------------------------------
 ### Some standard transports.
@@ -229,50 +397,111 @@ m4_define(<:USER_DELIVERY:>,
 	envelope_to_add = true
 	return_path_add = true:>)
 
+m4_define(<:APPLY_HEADER_CHANGES:>,
+	<:headers_add = m4_ifelse(<:$1:>, <::>,
+		<:$acl_m_hdradd:>,
+		<:${if def:acl_m_hdradd{$acl_m_hdradd\n}}\
+		$1:>)
+	headers_remove = m4_ifelse(<:$2:>, <::>,
+		<:$acl_m_hdrrm:>,
+		<:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
+		$2:>):>)
+
 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
+	APPLY_HEADER_CHANGES
 	tls_require_ciphers = CONF_acceptable_ciphers
-	tls_dh_min_bits = 1020
+	tls_dh_min_bits = 508
 	tls_tempfail_tryclear = true
 
+m4_define(<:SMTP_TRANS_DHBITS:>,
+	<:driver = smtp
+	APPLY_HEADER_CHANGES
+	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_512:
+	SMTP_TRANS_DHBITS(508)
+smtp_dhbits_768:
+	SMTP_TRANS_DHBITS(764)
+smtp_dhbits_1024:
+	SMTP_TRANS_DHBITS(1020)
+smtp_dhbits_2048:
+	SMTP_TRANS_DHBITS(2044)
+
 ## Transport to a local SMTP server; use TLS and perform client
 ## authentication.
 smtp_local:
 	driver = smtp
+	APPLY_HEADER_CHANGES
 	hosts_require_tls = *
-	tls_certificate = CONF_sysconf_dir/client.cert
+	tls_certificate = CONF_sysconf_dir/client.certlist
 	tls_privatekey = CONF_sysconf_dir/client.key
 	tls_verify_certificates = CONF_ca_dir/ca.cert
 	tls_require_ciphers = CONF_good_ciphers
-	tls_dh_min_bits = 3070
+	tls_dh_min_bits = 2046
 	tls_tempfail_tryclear = false
-	authenticated_sender = ${if def:authenticated_id \
-				    ${authenticated_id@CONF_master_domain} \
-				    fail}
+	authenticated_sender_force = true
+	authenticated_sender = \
+		${if def:acl_m_user {$acl_m_user@CONF_master_domain} \
+		     {${if def:authenticated_sender {$authenticated_sender} \
+			   fail}}}
 
 ## A standard transport for local delivery.
 deliver:
 	driver = appendfile
+	APPLY_HEADER_CHANGES
 	file = /var/mail/$local_part
+	group = mail
+	mode = 0600
+	mode_fail_narrower = false
 	USER_DELIVERY
 
 ## Transports for user filters.
 mailbox:
 	driver = appendfile
+	APPLY_HEADER_CHANGES
+	initgroups = true
 	USER_DELIVERY
 
 maildir:
 	driver = appendfile
+	APPLY_HEADER_CHANGES
 	maildir_format = true
+	initgroups = true
 	USER_DELIVERY
 
 pipe:
 	driver = pipe
-	return_output = true
+	APPLY_HEADER_CHANGES
+	path = ${if and {{def:home} {exists{$home/bin}}} {$home/bin:} {}}\
+		/usr/local/bin:/usr/local/sbin:\
+		/usr/bin:/usr/sbin:/bin:/sbin
+	initgroups = true
+	umask = 002
+	return_fail_output = true
+	log_output = true
 
 ## A special dummy transport for use during address verification.
 dummy: