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comparison mod_dnsbl/mod_dnsbl.lua @ 6133:99860e1b817d

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mod_dnsbl: Flag accounts registered by IPs matching blocklists
author Matthew Wild <mwild1@gmail.com>
date Wed, 22 Jan 2025 18:04:26 +0000
parents
children ec4a0e4d950e
comparison
equal deleted inserted replaced
6132:4887f68130c0 6133:99860e1b817d
1 local lfs = require "lfs";
2
3 local adns = require "net.adns";
4 local it = require "util.iterators";
5 local parse_cidr = require "util.ip".parse_cidr;
6 local parse_ip = require "util.ip".new_ip;
7 local promise = require "util.promise";
8 local set = require "util.set";
9 local st = require "util.stanza";
10
11 local render_message = require "util.interpolation".new("%b{}", function (s)
12 return s;
13 end);
14
15 local trie = module:require("mod_anti_spam/trie");
16
17 local dnsbls_config_raw = module:get_option("dnsbls");
18 local default_dnsbl_flag = module:get_option_string("dnsbl_flag", "dnsbl_hit");
19 local default_dnsbl_message = module:get_option("dnsbl_message");
20
21 if not dnsbls_config_raw then
22 module:log_status("error", "No 'dnsbls' in config file");
23 return;
24 end
25
26 local dnsbls = set.new();
27 local dnsbls_config = {};
28
29 for k, v in ipairs(dnsbls_config_raw) do
30 local dnsbl_name, dnsbl_config;
31 if type(k) == "string" then
32 dnsbl_name = k;
33 dnsbl_config = v;
34 else
35 dnsbl_name = v;
36 dnsbl_config = {};
37 end
38 dnsbls:add(dnsbl_name);
39 dnsbls_config[dnsbl_name] = dnsbl_config;
40 end
41
42 local function read_dnsbl_file(filename)
43 local t = trie.new();
44 local f, err = io.open(filename);
45 if not f then
46 module:log("error", "Failed to read file: %s", err);
47 return t;
48 end
49
50 local n_line, n_added = 0, 0;
51 for line in f:lines() do
52 n_line = n_line + 1;
53 line = line:gsub("#.+$", ""):match("^%s*(.-)%s*$");
54 if line == "" then -- luacheck: ignore 542
55 -- Skip
56 else
57 local parsed_ip, parsed_bits = parse_cidr(line);
58 if not parsed_ip then
59 -- Skip
60 module:log("warn", "Failed to parse IP/CIDR on %s:%d", filename, n_line);
61 else
62 if not parsed_bits then
63 -- Default to full length of IP address
64 parsed_bits = #parsed_ip.packed * 8;
65 end
66 t:add_subnet(parsed_ip, parsed_bits);
67 n_added = n_added + 1;
68 end
69 end
70 end
71
72 module:log("info", "Loaded %d entries from %s", n_added, filename);
73
74 return t;
75 end
76
77 local ipsets = {};
78 local ipsets_last_updated = {};
79
80 function reload_file_dnsbls()
81 for dnsbl in dnsbls do
82 if dnsbl:byte(1) == 64 then -- '@'
83 local filename = dnsbl:sub(2);
84 local file_last_updated = lfs.attributes(filename, "change");
85 if (ipsets_last_updated[dnsbl] or 0) < file_last_updated then
86 ipsets[dnsbl] = read_dnsbl_file(filename);
87 ipsets_last_updated[dnsbl] = file_last_updated;
88 end
89 end
90 end
91 end
92
93 module:hook_global("config-reloaded", reload_file_dnsbls);
94 reload_file_dnsbls();
95
96 local mod_flags = module:depends("flags");
97
98 local function reverse(ip, suffix)
99 local a,b,c,d = ip:match("^(%d+).(%d+).(%d+).(%d+)$");
100 if not a then return end
101 return ("%d.%d.%d.%d.%s"):format(d,c,b,a, suffix);
102 end
103
104 function check_dnsbl(ip_address, dnsbl, callback, ud)
105 if dnsbl:byte(1) == 64 then -- '@'
106 local parsed_ip = parse_ip(ip_address);
107 if not parsed_ip then
108 module:log("warn", "Failed to parse IP address: %s", ip_address);
109 callback(ud, false, dnsbl);
110 return;
111 end
112 callback(ud, not not ipsets[dnsbl]:contains_ip(parsed_ip), dnsbl);
113 return;
114 else
115 if ip_address:sub(1,7):lower() == "::ffff:" then
116 ip_address = ip_address:sub(8);
117 end
118
119 local rbl_ip = reverse(ip_address, dnsbl);
120 if not rbl_ip then return; end
121
122 module:log("debug", "Sending DNSBL lookup for %s", ip_address);
123 adns.lookup(function (reply)
124 local hit = not not (reply and reply[1]);
125 module:log("debug", "Received DNSBL result for %s: %s", ip_address, hit and "present" or "absent");
126 callback(ud, hit, dnsbl);
127 end, rbl_ip);
128 end
129 end
130
131 local function handle_dnsbl_register_result(registration_event, hit, dnsbl)
132 if not hit then return; end
133
134 if registration_event.dnsbl_match then return; end
135 registration_event.dnsbl_match = true;
136
137 local username = registration_event.username;
138 local flag = dnsbls_config[dnsbl].flag or default_dnsbl_flag;
139
140 module:log("info", "Flagging %s for user %s registered from %s matching %s", flag, username, registration_event.ip, dnsbl);
141
142 mod_flags:add_flag(username, flag, "Matched "..dnsbl);
143
144 local msg = dnsbls_config[dnsbl].message or default_dnsbl_message;
145
146 if msg then
147 module:log("debug", "Sending warning message to %s", username);
148 local msg_stanza = st.message(
149 {
150 to = username.."@"..module.host;
151 from = module.host;
152 },
153 render_message(msg, { registration = registration_event })
154 );
155 module:send(msg_stanza);
156 end
157 end
158
159 module:hook("user-registered", function (event)
160 local session = event.session;
161 local ip = event.ip or (session and session.ip);
162 if not ip then return; end
163
164 if not event.ip then
165 event.ip = ip;
166 end
167
168 for dnsbl in dnsbls do
169 check_dnsbl(ip, dnsbl, handle_dnsbl_register_result, event);
170 end
171 end);
172
173 module:add_item("account-trait", {
174 name = "register-dnsbl-hit";
175 prob_bad_true = 0.6;
176 prob_bad_false = 0.4;
177 });
178
179 module:hook("get-account-traits", function (event)
180 event.traits["register-dnsbl-hit"] = mod_flags.has_flag(event.username, default_dnsbl_flag);
181 end);
182
183 module:add_item("shell-command", {
184 section = "dnsbl";
185 section_desc = "Manage DNS blocklists";
186 name = "lists";
187 desc = "Show all lists currently in use on the specified host";
188 args = {
189 { name = "host", type = "string" };
190 };
191 host_selector = "host";
192 handler = function(self, host) --luacheck: ignore 212/self 212/host
193 local count = 0;
194 for list in dnsbls do
195 count = count + 1;
196 self.session.print(list);
197 end
198 return true, ("%d lists"):format(count);
199 end;
200 });
201
202 module:add_item("shell-command", {
203 section = "dnsbl";
204 section_desc = "Manage DNS blocklists";
205 name = "check";
206 desc = "Check an IP against the configured block lists";
207 args = {
208 { name = "host", type = "string" };
209 { name = "ip_address", type = "string" };
210 };
211 host_selector = "host";
212 handler = function(self, host, ip_address) --luacheck: ignore 212/self 212/host
213 local parsed_ip = parse_ip(ip_address);
214 if not parsed_ip then
215 return false, "Failed to parse IP address";
216 end
217
218 local matches, total = 0, 0;
219
220 local promises = {};
221
222 for dnsbl in dnsbls do
223 total = total + 1;
224 promises[dnsbl] = promise.new(function (resolve)
225 check_dnsbl(parsed_ip, dnsbl, resolve, true);
226 end);
227 end
228
229 return promise.all_settled(promises):next(function (results)
230 for dnsbl, result in it.sorted_pairs(results) do
231 local msg;
232 if result.status == "fulfilled" then
233 if result.value then
234 msg = "[X]";
235 matches = matches + 1;
236 else
237 msg = "[ ]";
238 end
239 else
240 msg = "[?]";
241 end
242
243 print(msg, dnsbl);
244 end
245 return ("Found in %d of %d lists"):format(matches, total);
246 end);
247 end;
248 });