3 ### Spam filtering for distorted.org.uk Exim configuration
5 ### (c) 2012 Mark Wooding
8 ###----- Licensing notice ---------------------------------------------------
10 ### This program is free software; you can redistribute it and/or modify
11 ### it under the terms of the GNU General Public License as published by
12 ### the Free Software Foundation; either version 2 of the License, or
13 ### (at your option) any later version.
15 ### This program is distributed in the hope that it will be useful,
16 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ### GNU General Public License for more details.
20 ### You should have received a copy of the GNU General Public License
21 ### along with this program; if not, write to the Free Software Foundation,
22 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
25 ###--------------------------------------------------------------------------
28 SECTION(global, policy)m4_dnl
29 spamd_address = CONF_spamd_address CONF_spamd_port
31 SECTION(routers, allspam)m4_dnl
32 ## If we're verifying an address and the recipient has a `~/.mail/spam-limit'
33 ## file, then look up the recipient and sender addresses to find a plausible
34 ## limit and insert it into the `address_data' where the RCPT ACL can find
35 ## it. This router always declines, so it doesn't affect the overall outcome
36 ## of the verification.
41 local_part_suffix = CONF_user_suffix_list
42 local_part_suffix_optional = true
45 ${if def:address_data {$address_data}{}} \
46 ${if exists {CONF_userconf_dir/spam-limit} \
47 {${lookup {$local_part_prefix\
52 nwildlsearch {CONF_userconf_dir/spam-limit} \
56 ${if exists {CONF_userconf_dir/spam-limit.userv} \
57 {${run {timeout 5s -- \
58 userv $local_part exim-spam-limit \
64 {${if match{$value}{\N^[0-9]+$\N} \
70 SECTION(acl, rcpt-hooks)m4_dnl
71 ## Do per-recipient spam-filter processing.
72 require acl = rcpt_spam
74 SECTION(acl, misc)m4_dnl
77 ## If the client is trusted, don't bother with any of this.
78 accept hosts = +trusted
80 ## Always accept mail to `postmaster'. Currently this is not
81 ## negotiable; maybe a tweak can be added to `domains.conf' if
83 accept local_parts = postmaster
85 ## Collect the user's spam threshold from the `address_data'
86 ## variable, where it was left by the `fetch_spam_limit' router
87 ## during recipient verification. (This just saves duplicating this
88 ## enormous expression.)
89 warn set acl_m_this_spam_limit = \
90 ${sg {${extract {spam_limit} \
91 {${if def:address_data \
94 {^(|.*\\D.*)\$}{CONF_spam_max}}
96 ## If there's a spam limit already established, and it's different
97 ## from this user's limit, then the sender will have to try this user
99 defer !hosts = +trusted
100 message = "You'd better try this one later"
101 condition = ${if def:acl_m_spam_limit {true}{false}}
102 condition = ${if ={$acl_m_spam_limit} \
103 {$acl_m_this_spam_limit} \
106 ## There's no limit set yet, or the user's limit is the same as the
107 ## existing one, or the client's local and we're not checking for
108 ## spam anyway. Whichever way, it's safe to set it now.
109 warn set acl_m_spam_limit = $acl_m_this_spam_limit
114 SECTION(acl, data-spam)m4_dnl
116 require acl = data_spam
118 SECTION(acl, misc)m4_dnl
121 ## If the client is trusted, don't bother with any of this.
122 accept hosts = +trusted
124 ## Check header validity.
125 require verify = header_syntax
127 ## Check the message for spam, comparing to the configured limit.
128 deny spam = exim:true
129 message = Tinned meat product detected ($spam_score)
130 condition = ${if >{$spam_score_int}{$acl_m_spam_limit} \
133 ## Insert headers from the spam check now that we've decided to
134 ## accept the message.
137 ## Convert the limit (currently 10x fixed point) into a
138 ## decimal for presentation.
139 set acl_m_spam_limit_presentation = \
140 ${sg{$acl_m_spam_limit}{\N(\d)$\N}{.\$1}}
142 ## Convert the report into something less obnoxious. Plain
143 ## old SpamAssassin has an `X-Spam-Status' header which
144 ## lists the matched rules and provides some other basic
145 ## information. Try to extract something similar from the
148 ## This is rather fiddly.
150 ## Firstly, escape angle brackets, because we'll be using
151 ## them for our own purposes.
152 set acl_m_spam_tests = ${sg{$spam_report}{([!<>])}{!\$1}}
154 ## Trim off the blurb paragraph and the preview. The rest
155 ## should be fairly well behaved. Wrap double angle-
156 ## brackets around the remainder; these can't appear in the
157 ## body because we escaped them all earlier.
158 set acl_m_spam_tests = \
159 ${sg{$acl_m_spam_tests} \
160 {\N^(?s).*\n Content analysis details:(.*)$\N} \
163 ## Extract the information about the matching rules and
164 ## their scores. Leave `<<...>>' around everything else.
165 set acl_m_spam_tests = \
166 ${sg{$acl_m_spam_tests} \
167 {\N(?s)\n\s*(-?[\d.]+)\s+([-\w]+)\s\N} \
170 ## Strip everything still in `<<...>>' pairs, including any
171 ## escaped characters inside.
172 set acl_m_spam_tests = \
173 ${sg{$acl_m_spam_tests}{\N(?s)<<([^!>]+|!.)*>>\N}{}}
175 ## Trim off a trailing comma.
176 set acl_m_spam_tests = ${sg{$acl_m_spam_tests}{,\s*\$}{}}
178 ## Undo the escaping.
179 set acl_m_spam_tests = ${sg{$acl_m_spam_tests}{!(.)}{\$1}}
181 ## Insert the headers.
182 add_header = X-SpamAssassin-Score: \
183 $spam_score/$acl_m_spam_limit_presentation \
185 add_header = X-SpamAssassin-Status: \
187 limit=$acl_m_spam_limit_presentation, \n\t\
188 tests=$acl_m_spam_tests
194 ###----- That's all, folks --------------------------------------------------