iankelling.org Git - distro-setup/blob - filesystem/etc/exim4/conf.d/acl/40_exim4-config_check_data

   1
   2 ### acl/40_exim4-config_check_data
   3 #################################
   4
   5 # This ACL is used after the contents of a message have been received. This
   6 # is the ACL in which you can test a message's headers or body, and in
   7 # particular, this is where you can invoke external virus or spam scanners.
   8
   9 acl_check_data:
  10
  11   # Deny if the message contains an overlong line.  Per the standards
  12   # we should never receive one such via SMTP.
  13   #
  14   .ifndef IGNORE_SMTP_LINE_LENGTH_LIMIT
  15   deny    message    = maximum allowed line length is 998 octets, \
  16                        got $max_received_linelength
  17           condition  = ${if > {$max_received_linelength}{998}}
  18   .endif
  19
  20   # Deny unless the address list headers are syntactically correct.
  21   #
  22   # If you enable this, you might reject legitimate mail.
  23   .ifdef CHECK_DATA_VERIFY_HEADER_SYNTAX
  24   deny
  25     message = Message headers fail syntax check
  26     !acl = acl_local_deny_exceptions
  27     !verify = header_syntax
  28   .endif
  29
  30
  31   # require that there is a verifiable sender address in at least
  32   # one of the "Sender:", "Reply-To:", or "From:" header lines.
  33   .ifdef CHECK_DATA_VERIFY_HEADER_SENDER
  34   deny
  35     message = No verifiable sender address in message headers
  36     !acl = acl_local_deny_exceptions
  37     !verify = header_sender
  38   .endif
  39
  40
  41   # Deny if the message contains malware. Before enabling this check, you
  42   # must install a virus scanner and set the av_scanner option in the
  43   # main configuration.
  44   #
  45   # exim4-daemon-heavy must be used for this section to work.
  46   #
  47   # deny
  48   #   malware = *
  49   #   message = This message was detected as possible malware ($malware_name).
  50
  51
  52   # Add headers to a message if it is judged to be spam. Before enabling this,
  53   # you must install SpamAssassin. You also need to set the spamd_address
  54   # option in the main configuration.
  55   #
  56   # exim4-daemon-heavy must be used for this section to work.
  57   #
  58   # Please note that this is only suiteable as an example. There are
  59   # multiple issues with this configuration method. For example, if you go
  60   # this way, you'll give your spamassassin daemon write access to the
  61   # entire exim spool which might be a security issue in case of a
  62   # spamassassin exploit.
  63   #
  64   # See the exim docs and the exim wiki for more suitable examples.
  65   #
  66
  67 # ian: uncommented this. The above comment about this not
  68 # being suitable is mostly bs. The only thing I found was to
  69 # add the condition, cuz spamassassin has problems with big
  70 # messages and spammers don't bother with big messages,
  71 # but I've increased the size from 10k
  72 # suggested in official docs, and 100k in the wiki example because
  73 # those docs are rather old and I see a 110k spam message
  74 # pretty quickly looking through my spam folder.
  75   warn
  76     condition = ${if < {$message_size}{1000K}}
  77     spam = Debian-exim:true
  78     add_header = X-Spam_score: $spam_score\n\
  79               X-Spam_score_int: $spam_score_int\n\
  80               X-Spam_bar: $spam_bar\n\
  81               X-Spam_report: $spam_report
  82
  83
  84   # This hook allows you to hook in your own ACLs without having to
  85   # modify this file. If you do it like we suggest, you'll end up with
  86   # a small performance penalty since there is an additional file being
  87   # accessed. This doesn't happen if you leave the macro unset.
  88   .ifdef CHECK_DATA_LOCAL_ACL_FILE
  89   .include CHECK_DATA_LOCAL_ACL_FILE
  90   .endif
  91
  92
  93   # accept otherwise
  94   accept