fix for forwarding save option, added SRS

etc/exim4/bounce_message_text

@@ -0,0 +1,12 @@
+****
+
+This message was created automatically by the mail delivery software on $primary_hostname:
+
+A message ${if eq{$sender_address}{$bounce_recipient}{that you sent}{sent by\n}}
+${if ! eq{$sender_address}{$bounce_recipient} {${if match {$sender_address} {\N(?i)^SRS[01][=+-]\N} {${sg {${sg {$sender_address} {\N(?i)^SRS[01][=+-][^ @]+?[=+-][a-zA-Z0-9]{2}[=+-]([^ @]+?)[=+-]([^ @]++)@.*$\N} {\N  $2@$1\N}} } {\N^  prvs=[^=]+?=(.*)$\N} {\N  $1\N} }\n} {${if match {$sender_address} {\N(?i)^prvs=\N} {${sg {$sender_address} {\N(?i)^prvs=[^ @]+?=(.*@.*)$\N} {\N  $1\n\N}}} {  $sender_address\n}}} }}}
+could not be delivered to one or more of its recipients. The following
+address(es) failed:
+****
+****
+****
+****

etc/exim4/exim4.conf

@@ -7,6 +7,7 @@ disable_ipv6 = true
 keep_environment =
 add_environment = PATH=/usr/sbin:/usr/bin:/sbin:/bin
 smtp_enforce_sync = false
+bounce_message_file = /etc/exim4/bounce_message_text
 
 smtp_accept_max = 50
 smtp_accept_max_per_host = 10
@@ -202,7 +203,7 @@ rfc1413_query_timeout = 0s
 
 ignore_bounce_errors_after = 0s
 
-# This option cancels (removes) frozen messages that are older than a week.
+# This option cancels (removes) frozen messages that are older than a day.
 
 timeout_frozen_after = 1d
 
@@ -433,6 +434,32 @@ acl_rcpt_to:
   # Recipent Address Checks
   ######################################################################
 
+  # Ensure only valid SRS prefixed bounce message get accepted
+  deny
+    senders = :
+    domains = +local_domains
+    local_parts = ${if match {$local_part} {(?i)\N^SRS[01][=+-]\N} {$local_part}}
+    control = caseful_local_part
+    condition = ${if match{${readsocket{/run/srsd/srsd.sock}{REVERSE $local_part@$domain}{5s}{\n}}}{^ERROR: .* Invalid hash at .*}}
+    message = Invalid reverse path (SRS check failed on $local_part@$domain).
+
+  warn
+    senders = :
+    domains = +local_domains
+    local_parts = ${if match {$local_part} {\N^srs[01][=+-]\N} {$local_part}}
+    control = caseful_local_part
+    condition = ${if match{${readsocket{/run/srsd/srsd.sock}{REVERSE $local_part@$domain}{5s}{ }}}{^SRS: Case insensitive hash match detected. Someone smashed case in the local-part. .*}}
+    log_message = SRS hash smashed on the way for $local_part@$domain by case insensitive MTA.
+
+  # this is for debugging only. can be safely removed any time
+  warn
+    senders = :
+    domains = +local_domains
+    local_parts = ${if match {$local_part} {(?i)\N^SRS[01][=+-]\N} {$local_part}}
+    control = caseful_local_part
+    condition = ${if !match{${readsocket{/run/srsd/srsd.sock}{REVERSE $local_part@$domain}{5s}{\n}}}{^ERROR: .* Invalid hash at .*}}
+    log_message = Incoming SRS bounce to $local_part@$domain
+
   # Deny if the local part contains @ or % or / or | or !. These are
   # rarely found in genuine local parts, but are often tried by people
   # looking to circumvent relaying restrictions.
@@ -697,6 +724,33 @@ autowhitelist_filter:
   unseen
   allow_filter = true
 
+srs_bounce:
+  senders = :
+  driver = redirect
+  domains = +local_domains
+  allow_fail
+  allow_defer
+  local_part_prefix = srs0+ : srs0- : srs0= : srs1+ : srs1- : srs1=
+  caseful_local_part
+  address_data = ${readsocket{/run/srsd/srsd.sock}{REVERSE $local_part_prefix$local_part@$domain}{5s}{ }{:defer: SRS daemon failure}}
+  data = ${sg {$address_data} {^SRS: Case insensitive hash match detected. Someone smashed case in the local-part\. .* ([^ ]+)@([^ ]+)\$} {\N$1@$2\N} }
+  headers_add = X-SRS: Decoded valid SRS return address to ${quote_local_part:${local_part:$address_data}}@${domain:$address_data} by $primary_hostname
+
+srs_forward:
+  driver = redirect
+  senders = ! : ! *@+local_domains
+  domains = ! +local_domains : ! +relay_to_domains
+  condition = ${lookup mysql{SELECT vm_domains.id FROM vm_domains WHERE vm_domains.domain='${original_domain}' AND vm_domains.status = '1'}}
+  address_data = ${readsocket{/run/srsd/srsd.sock}\
+                {FORWARD $sender_address_local_part@$sender_address_domain $original_domain\n}\
+                                        {5s}{\n}{:defer: SRS daemon failure}}
+  errors_to = ${quote_local_part:${local_part:$address_data}}@${domain:$address_data}
+  data = ${quote_local_part:$local_part}@$domain
+  headers_add = X-SRS-Forward: from $sender_address to $original_local_part@$original_domain forwarded to $local_part@$domain by $primary_hostname
+  repeat_use = false
+  allow_defer
+  no_verify
+
 # This router routes addresses that are not in local domains by doing a DNS
 # lookup on the domain name. Any domain that resolves to 0.0.0.0 or to a
 # loopback interface address (127.0.0.0/8) is treated as if it had no DNS
@@ -735,24 +789,6 @@ junk_filter:
   condition = ${lookup mysql{SELECT vm_mboxes.id FROM vm_domains, vm_mboxes WHERE vm_domains.domain='${domain}' AND vm_mboxes.mbox='${local_part}' AND vm_domains.id = vm_mboxes.domain_id AND vm_domains.status = '1' AND vm_mboxes.status = '1' AND vm_mboxes.filter > '0'}}
   transport = junk_delivery
 
-spamcheck_router:
-  driver = accept
-  domains = +local_domains
-  local_part_suffix = +*
-  local_part_suffix_optional = true
-  condition = ${if and { \
-              { !eq {$received_protocol}{spam-scanned}} \
-              { !eq {$sender_address_domain}{$domain}} \
-              { < {$message_size}{512k}} \
-              { !eq {$header_X-Junk-Flag:}{YES}} \
-              { !eq {$header_X-Whitelist-Flag:}{YES}} \
-              { eq {${lookup mysql{SELECT vm_mboxes.status FROM vm_domains, vm_mboxes WHERE vm_domains.domain='${domain}' AND vm_mboxes.mbox='${local_part}' AND vm_domains.id = vm_mboxes.domain_id AND vm_domains.status = '1'}{$value}fail}}{1} } \
-              } {yes} {no}}
-  # check domain & mbox 'status'?
-  # Check for other headers too? Blacklist, SPF, DKIM failers go directly to Spam folder without spam scan??? - actually they should go to spam folder before this router is hit?
-  headers_remove = X-Spam-Checker-Version:X-Spam-Flag:X-Spam-Level:X-Spam-Status:X-Spam-Score:X-Spam-Report
-  transport = spamcheck
-
 spam_filter:
   driver = accept
   domains = +local_domains
@@ -772,6 +808,7 @@ virtual_vacation:
   # do not reply to errors or lists or spam-scanned messages, require vacation message in db
   condition = ${if and { \
               { !match {$h_precedence:} {(?i)junk|bulk|list}} \
+              { !eq {$received_protocol}{spam-scanned}} \
               { !eq {$sender_address} {}} \
               { eq {${lookup mysql{SELECT vm_autoresponders.mode FROM vm_domains, vm_mboxes, vm_autoresponders WHERE vm_domains.domain='${domain}' AND vm_mboxes.mbox='${local_part}' AND vm_domains.id = vm_mboxes.domain_id AND vm_autoresponders.mbox_id = vm_mboxes.id AND vm_domains.status = '1' AND vm_mboxes.status = '1' AND vm_autoresponders.status = '1'}{$value}fail}}{Vacation}} \
               } {yes} {no}}
@@ -797,6 +834,7 @@ virtual_autoresponder:
   # do not reply to errors or lists or spam-scanned messages, require autoresponder message in db
   condition = ${if and { \
               { !match {$h_precedence:} {(?i)junk|bulk|list}} \
+              { !eq {$received_protocol}{spam-scanned}} \
               { !eq {$sender_address} {}} \
               { eq {${lookup mysql{SELECT vm_autoresponders.mode FROM vm_domains, vm_mboxes, vm_autoresponders WHERE vm_domains.domain='${domain}' AND vm_mboxes.mbox='${local_part}' AND vm_domains.id = vm_mboxes.domain_id AND vm_autoresponders.mbox_id = vm_mboxes.id AND vm_domains.status = '1' AND vm_mboxes.status = '1' AND vm_autoresponders.status = '1'}{$value}fail}}{Autoresponder} } \
               } {yes} {no}}
@@ -813,13 +851,38 @@ virtual_autoresponder:
   unseen
   no_verify
 
-virtual_forward:
+virtual_forward_and_drop:
   driver = redirect
   domains = +local_domains
+  condition = ${if !eq {$received_protocol}{spam-scanned}}
+  local_part_suffix = +*
+  local_part_suffix_optional = true
+  data = ${lookup mysql{SELECT vm_forwards.forward_to FROM vm_domains, vm_mboxes, vm_forwards WHERE vm_domains.domain='${domain}' AND vm_domains.id = vm_mboxes.domain_id AND vm_mboxes.mbox='${local_part}' AND vm_mboxes.id=vm_forwards.mbox_id AND vm_domains.status = '1' AND vm_mboxes.status = '1' AND vm_forwards.save_local='0'}}
+
+virtual_forward_and_keep:
+  driver = redirect
+  domains = +local_domains
+  condition = ${if !eq {$received_protocol}{spam-scanned}}
+  local_part_suffix = +*
+  local_part_suffix_optional = true
+  data = ${lookup mysql{SELECT CONCAT('${local_part}@${domain}\n', vm_forwards.forward_to) FROM vm_domains, vm_mboxes, vm_forwards WHERE vm_domains.domain='${domain}' AND vm_domains.id = vm_mboxes.domain_id AND vm_mboxes.mbox='${local_part}' AND vm_mboxes.id=vm_forwards.mbox_id AND vm_domains.status = '1' AND vm_mboxes.status = '1' AND vm_forwards.save_local='1'}}
+
+spamcheck_router:
+  driver = accept
+  domains = +local_domains
   local_part_suffix = +*
   local_part_suffix_optional = true
-  data = ${lookup mysql{SELECT vm_forwards.forward_to FROM vm_domains, vm_mboxes, vm_forwards WHERE vm_domains.domain='${domain}' AND vm_domains.id = vm_mboxes.domain_id AND vm_mboxes.mbox='${local_part}' AND vm_mboxes.id=vm_forwards.mbox_id AND vm_domains.status = '1' AND vm_mboxes.status = '1' }}
+  condition = ${if and { \
-  unseen = ${lookup mysql{SELECT vm_forwards.id FROM vm_domains, vm_mboxes, vm_forwards WHERE vm_domains.domain='${domain}' AND vm_domains.id = vm_mboxes.domain_id AND vm_mboxes.mbox='${local_part}' AND vm_mboxes.id=vm_forwards.mbox_id AND vm_domains.status = '1' AND vm_mboxes.status = '1' AND vm_forwards.save_local='1'}{true}{false}}
+              { !eq {$received_protocol}{spam-scanned}} \
+              { !eq {$sender_address_domain}{$domain}} \
+              { < {$message_size}{512k}} \
+              { !eq {$header_X-Junk-Flag:}{YES}} \
+              { !eq {$header_X-Whitelist-Flag:}{YES}} \
+              { eq {${lookup mysql{SELECT vm_mboxes.status FROM vm_domains, vm_mboxes WHERE vm_domains.domain='${domain}' AND vm_mboxes.mbox='${local_part}' AND vm_domains.id = vm_mboxes.domain_id AND vm_domains.status = '1' AND vm_mboxes.status = '1'}{$value}fail}}{1} } \
+              } {yes} {no}}
+  # Check for other headers too? Blacklist, SPF, DKIM failers go directly to Spam folder without spam scan??? - actually they should go to spam folder before this router is hit?
+  headers_remove = X-Spam-Checker-Version:X-Spam-Flag:X-Spam-Level:X-Spam-Status:X-Spam-Score:X-Spam-Report
+  transport = spamcheck
 
 user_filter:
   driver = redirect
@@ -1094,10 +1157,8 @@ address_reply:
 begin retry
 
 # This single retry rule applies to all domains and all errors. It specifies
-# retries every 15 minutes for 2 hours, then increasing retry intervals,
+# retries every 15 minutes for 2 hours, then every 2 hours until 1 full day
-# starting at 1 hour and increasing each time by a factor of 1.5, up to 16
+# has passed since the first delivery failed.
-# hours, then retries every 6 hours until 4 days have passed since the first
-# failed delivery.
 
 # Domain               Error       Retries
 # ------               -----       -------
@@ -1114,7 +1175,6 @@ begin retry
 begin rewrite
 
 
-
 ######################################################################
 #                   AUTHENTICATION CONFIGURATION                     #
 ######################################################################

install.sh

@@ -59,7 +59,7 @@ mysql -e "GRANT ALL PRIVILEGES ON vmail.* TO 'vmail'@'localhost';"
 mysqladmin flush-privileges
 
 # install mail server software
-apt -y install exim4-daemon-heavy spf-tools-perl spamassassin libclass-dbi-mysql-perl dovecot-core dovecot-imapd dovecot-mysql dovecot-pop3d dovecot-lmtpd
+apt -y install exim4-daemon-heavy spf-tools-perl spamassassin srs libclass-dbi-mysql-perl dovecot-core dovecot-imapd dovecot-mysql dovecot-pop3d dovecot-lmtpd
 
 # configure system users
 apt -y install ssl-cert
@@ -97,6 +97,16 @@ chmod 644 /etc/spamassassin/local.cf
 chown debian-spamd:mail /etc/spamassassin/sql.cf
 chmod 640 /etc/spamassassin/sql.cf
 
+# srsd
+# bug fixes for libmail-srs-perl. still needed as of v0.31-6 on Ubuntu 20.04
+sed -i 's|/tmp/srsd|/run/srsd/srsd.sock|' /usr/share/perl5/Mail/SRS/Daemon.pm
+sed -i '/Until we decide that forward/,+3d' /usr/share/perl5/Mail/SRS/Daemon.pm
+cp systemd/srsd.service /lib/systemd/system/srsd.service
+chmod 644 /lib/systemd/system/srsd.service
+systemctl daemon-reload
+systemctl enable srsd
+systemctl start srsd
+
 # exim config
 maildomain=`hostname -d`
 sed -i 's/size 10M/daily/g' /etc/logrotate.d/exim4-paniclog
@@ -112,6 +122,10 @@ chmod 640 /etc/exim4/skip_greylisting_hosts
 sed -i "s|example.com|$maildomain|g" /etc/exim4/skip_greylisting_hosts
 sed -i "s|password|$VMAILPASS|g" /etc/exim4/exim_local.conf
 sed -i "s|example.com|$maildomain|g" /etc/exim4/exim_local.conf
+touch /etc/exim4/srsd.secret
+chmod 640 /etc/exim4/srsd.secret
+chown Debian-exim:Debian-exim /etc/exim4/srsd.secret
+pwgen -N 1 -cny 64 > /etc/exim4/srsd.secret
 
 # dovecot config
 mkdir /etc/dovecot/sites.d

systemd/srsd.service

@@ -0,0 +1,15 @@
+[Unit]
+Description=Sender Rewriting Scheme Daemon
+
+[Service]
+Type=exec
+User=Debian-exim
+Group=Debian-exim
+ExecStart=/usr/bin/srsd --secretfile /etc/exim4/srsd.secret --hashlength 24
+PIDFile=/run/srsd/srsd.pid
+Restart=on-failure
+RuntimeDirectory=srsd
+RuntimeDirectoryMode=0750
+
+[Install]
+WantedBy=multi-user.target