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 25328e72627ea7284e9db82403a7769b5e8a276f..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} \
@@ -86,6 +88,7 @@ received_header_text = Received: \
 SECTION(global, smtp)m4_dnl
 smtp_return_error_details = true
 accept_8bitmime = true
+chunking_advertise_hosts =
 
 SECTION(global, env)m4_dnl
 keep_environment =
@@ -261,17 +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
@@ -284,6 +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
@@ -407,6 +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
@@ -418,11 +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, {*}{})
@@ -441,15 +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