X-Git-Url: https://git.distorted.org.uk/~mdw/exim-config/blobdiff_plain/2845f3f93c860740767f65416559b82ab43cb3ab..a6127611de9e7d36fecc4a59a0d1aad651e8092a:/base.m4

diff --git a/base.m4 b/base.m4
index 692a74b..4f16e20 100644
--- a/base.m4
+++ b/base.m4
@@ -128,7 +128,7 @@ SECTION(acl, misc)m4_dnl
 helo:
 	## Don't worry if this is local submission.  MUAs won't necessarily
 	## have a clear idea of their hostnames.  (For some reason.)
-	accept	 condition = ${if !eq{$acl_c_mode}{submission}}
+	accept	 condition = ${if eq{$acl_c_mode}{submission}}
 
 	## Check that the caller's claimed identity is actually plausible.
 	## This seems like it's a fairly effective filter on spamminess, but
@@ -213,8 +213,7 @@ mail_check_sender:
 
 	## See whether there's a special exception for this sender domain.
 	accept	 senders = ${LOOKUP_DOMAIN($sender_address_domain,
-			     {KV(senders, {$value}{})},
-			     {})}
+			     {KV(senders)})}
 
 	## Ensure that the sender is routable.  This is important to prevent
 	## undeliverable bounces.
@@ -420,6 +419,65 @@ m4_define(<:APPLY_HEADER_CHANGES:>,
 		<:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
 		$2:>):>)
 
+m4_define(<:DKIM_SIGN_P:>,
+	<:and {{exists{CONF_sysconf_dir/dkim-sign.conf}} \
+	       {!def:h_DKIM-Signature:} \
+	       {!def:h_List-ID:} \
+	       {or {{def:authenticated_id} \
+		    {def:authenticated_sender}}} \
+	       {bool {DKIM_KEYS_INSTANCE(<:{true}:>, <:{false}:>)}}}:>)
+
+m4_define(<:DKIM_KEYS_INSTANCE:>,
+	<:${lookup {${domain:$h_From:}} partial0-lsearch \
+			{CONF_sysconf_dir/dkim-sign.conf} \
+		_LOOKUP_ARGS(<:$1:>, <:$2:>)}:>)
+m4_define(<:DKIM_KEYS_STATE:>, <:${lookup {$1} lsearch \
+		{DKIM_KEYS_INSTANCE(<:{CONF_dkim_keys_dir/$value/active/dkim-keys.state}:>)} \
+	_LOOKUP_ARGS(<:$2:>, <:$3:>, <:fail:>)}:>)
+m4_define(<:DKIM_KEYS_INFO:>, <:DKIM_KEYS_STATE(<:params:>,
+	<:{${if and {{>={$tod_epoch}{KV(t0)}} \
+		    {<{$tod_epoch}{${eval:KV(t0) + KV(n)*KV(step)}}}} \
+		{DKIM_KEYS_STATE(<:info.${eval:($tod_epoch - KV(t0))/KV(step)}:>,
+			<:$1:>, <:$2:>)} \
+		m4_ifelse(<:$2:>, <::>, <:fail:>, <:$2:>)}}:>,
+	m4_ifelse(<:$2:>, <::>, <:fail:>, <:$2:>)):>)
+
+m4_define(<:DKIM_SIGN:>,
+	<:dkim_domain = \
+		${if DKIM_SIGN_P \
+			{DKIM_KEYS_INSTANCE({${domain:$h_From:}})}}
+	dkim_selector = DKIM_KEYS_INFO(<:{KV(k)}:>)
+	dkim_private_key = \
+		DKIM_KEYS_INSTANCE(<:m4_dnl
+			{CONF_dkim_keys_dir/$value/active/$dkim_selector.priv}:>)
+	dkim_canon = relaxed
+	dkim_strict = true
+	## The following ridiculous stunt does two important jobs.  Firstly,
+	## and more obviously, it arranges to include one more copy of each
+	## header name than the message actually contains, thereby causing
+	## the signature to fail if another header with the same name is
+	## added.  And secondly, and far more subtly, it also trims the
+	## spaces from the header names so that they're in the format that
+	## the signing machinery secretly wants.
+	dkim_sign_headers = \
+		${sg {${map {CONF_dkim_headers : \
+			     X-CONF_header_token-DKIM-Key-Publication} \
+			    {$item${sg {${expand:\$h_$item:}\n} \
+				       {((?:[^\n]+|\n\\s+)*)\n} \
+				       {:$item}}}}} \
+		     {::}{:}}
+	headers_add = \
+		${if DKIM_SIGN_P \
+			{DKIM_KEYS_INFO(<:m4_dnl
+				{X-CONF_header_token-DKIM-Key-Publication: \
+					DKIM signature not suitable \
+					as evidence after delivery;\n\t\
+					DKIM private key KV(k) will be \
+					published\n\t\
+					at KV(u)\n\t\
+					on or before KV(tpub)}:>)}}:>)
+
+
 m4_define(<:SMTP_DELIVERY:>,
 	<:## Prevent sending messages with overly long lines.  The use of
 	## `message_size_limit' here is somewhat misleading.
@@ -436,6 +494,7 @@ smtp:
 	driver = smtp
 	SMTP_DELIVERY
 	APPLY_HEADER_CHANGES
+	DKIM_SIGN
 	tls_require_ciphers = CONF_acceptable_ciphers
 	tls_dh_min_bits = 508
 	tls_tempfail_tryclear = true
@@ -444,6 +503,7 @@ m4_define(<:SMTP_TRANS_DHBITS:>,
 	<:driver = smtp
 	SMTP_DELIVERY
 	APPLY_HEADER_CHANGES
+	DKIM_SIGN
 	hosts_try_auth = *
 	hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
 	hosts_require_auth = \