base.m4: Neither accept nor transmit messages with long lines over SMTP.

[exim-config] / base.m4

diff --git a/base.m4 b/base.m4
index 947f52d04240665c5d2a0397c5bbc74587866060..4961012ef20bb0b148d6ec00552d87994ed66d27 100644 (file)
--- a/base.m4
+++ b/base.m4
@@ -59,6 +59,8 @@ gecos_name = $1
 gecos_pattern = ([^,:]*)
 
 SECTION(global, incoming)m4_dnl
+rfc1413_hosts = *
+rfc1413_query_timeout = 10s
 received_header_text = Received: \
        ${if def:sender_rcvhost \
             {from $sender_rcvhost\n\t} \
@@ -73,19 +75,31 @@ received_header_text = Received: \
        ${if def: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}}
 
 SECTION(global, smtp)m4_dnl
 smtp_return_error_details = true
 accept_8bitmime = true
+chunking_advertise_hosts =
+
+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
@@ -142,6 +156,7 @@ 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
@@ -249,17 +264,17 @@ check_relay:
        ## we're the correct place to send this mail.
 
        ## Known clients and authenticated users are OK.
-       accept    hosts = CONF_relay_clients
-       accept    authenticated = *
+       accept   hosts = CONF_relay_clients
+       accept   authenticated = *
 
        ## Known domains are OK.
-       accept    domains = +public
+       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} \
+       accept   domains = \
+                ${if exists{CONF_sysconf_dir/domains.conf} \
                     {partial0-lsearch; CONF_sysconf_dir/domains.conf}}
-                 condition = DOMKV(service, {$value}{true})
+                condition = DOMKV(service, {$value}{true})
 
        ## Nope, that's not allowed.
        deny
@@ -272,6 +287,10 @@ SECTION(global, acl)m4_dnl
 acl_smtp_data = data
 SECTION(acl, data)m4_dnl
 data:
+       ## Don't accept messages with overly-long lines.
+       deny     message = line length exceeds SMTP permitted maximum: \
+                       $max_received_linelength > 998
+                condition = ${if >{$max_received_linelength}{998}}
 
 SECTION(acl, data-tail)m4_dnl
        accept
@@ -307,6 +326,10 @@ mail_check_auth:
        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
 
@@ -391,6 +414,11 @@ m4_define(<:APPLY_HEADER_CHANGES:>,
                <:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
                $2:>):>)
 
+m4_define(<:SMTP_DELIVERY:>,
+       <:## Prevent sending messages with overly long lines.  The use of
+       ## `message_size_limit' here is somewhat misleading.
+       message_size_limit = ${if >{$max_received_linelength}{998}{1}{0}}:>)
+
 SECTION(transports)m4_dnl
 ## 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
@@ -402,11 +430,12 @@ 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
+       SMTP_DELIVERY
        APPLY_HEADER_CHANGES
        hosts_try_auth = *
        hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
@@ -425,15 +454,20 @@ m4_define(<:SMTP_TRANS_DHBITS:>,
                      {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(2046)
+       SMTP_TRANS_DHBITS(2044)
 
 ## Transport to a local SMTP server; use TLS and perform client
 ## authentication.
 smtp_local:
        driver = smtp
+       SMTP_DELIVERY
        APPLY_HEADER_CHANGES
        hosts_require_tls = *
        tls_certificate = CONF_sysconf_dir/client.certlist
@@ -442,9 +476,11 @@ smtp_local:
        tls_require_ciphers = CONF_good_ciphers
        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: