X-Git-Url: https://git.distorted.org.uk/~mdw/exim-config/blobdiff_plain/e12c95862063d5cba833a8db2852916eb5e4e87f..9384ef4f973dc22ca7e65b1710f1c486c4efad0c:/base.m4

diff --git a/base.m4 b/base.m4
index fee3626..62b46ab 100644
--- a/base.m4
+++ b/base.m4
@@ -25,6 +25,7 @@
 ### Global settings.
 
 SECTION(global, priv)m4_dnl
+admin_groups = CONF_admin_groups
 prod_requires_admin = false
 
 SECTION(global, logging)m4_dnl
@@ -58,18 +59,18 @@ 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}}\
 	id $message_exim_id\
@@ -96,16 +97,50 @@ 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 = \
+			${if exists {CONF_sysconf_dir/helo.conf} \
+			     {${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
+
+	## Done.
+	accept
+
+SECTION(global, acl)m4_dnl
 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.
+	warn	 condition = $acl_c_helo_warning
+		 add_header = :after_received:X-Distorted-Warning: \
+			BADHELO \
+			Client's HELO doesn't match its IP address.\n\t\
+			HELO name=$sender_helo_name, \
+			address=$sender_host_address
+
 	## Always allow the empty sender, so that we can receive bounces.
 	accept	 senders = :
 
@@ -119,6 +154,15 @@ 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
@@ -185,6 +229,51 @@ 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 = +localnet
+		!authenticated = *
+		 set acl_c_user = $sender_ident
+
+	## User must be authenticated.
+	deny	 message = Sender not authenticated
+		!hosts = +localnet
+		!authenticated = *
+
+	## 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 = ${LOOKUP_DOMAIN($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.
@@ -220,6 +309,15 @@ 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)
 ###--------------------------------------------------------------------------
 ### Some standard transports.
@@ -248,31 +346,42 @@ smtp_local:
 	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 \
-				    ${authenticated_id@CONF_master_domain} \
+				    {$authenticated_id@CONF_master_domain} \
 				    fail}
 
 ## A standard transport for local delivery.
 deliver:
 	driver = appendfile
 	file = /var/mail/$local_part
+	group = mail
+	mode = 0600
+	mode_fail_narrower = false
 	USER_DELIVERY
 
 ## Transports for user filters.
 mailbox:
 	driver = appendfile
+	initgroups = true
 	USER_DELIVERY
 
 maildir:
 	driver = appendfile
 	maildir_format = true
+	initgroups = true
 	USER_DELIVERY
 
 pipe:
 	driver = pipe
-	return_output = true
+	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: