1 /* $NetBSD: postscreen.c,v 1.4 2022/10/08 16:12:48 christos Exp $ */
2
3 /*++
4 /* NAME
5 /* postscreen 8
6 /* SUMMARY
7 /* Postfix zombie blocker
8 /* SYNOPSIS
9 /* \fBpostscreen\fR [generic Postfix daemon options]
10 /* DESCRIPTION
11 /* The Postfix \fBpostscreen\fR(8) server provides additional
12 /* protection against mail server overload. One \fBpostscreen\fR(8)
13 /* process handles multiple inbound SMTP connections, and decides
14 /* which clients may talk to a Postfix SMTP server process.
15 /* By keeping spambots away, \fBpostscreen\fR(8) leaves more
16 /* SMTP server processes available for legitimate clients, and
17 /* delays the onset of server overload conditions.
18 /*
19 /* This program should not be used on SMTP ports that receive
20 /* mail from end-user clients (MUAs). In a typical deployment,
21 /* \fBpostscreen\fR(8) handles the MX service on TCP port 25, and
22 /* \fBsmtpd\fR(8) receives mail from MUAs on the \fBsubmission\fR
23 /* service (TCP port 587) which requires client authentication.
24 /* Alternatively, a site could set up a dedicated, non-postscreen,
25 /* "port 25" server that provides \fBsubmission\fR service and
26 /* client authentication, but no MX service.
27 /*
28 /* \fBpostscreen\fR(8) maintains a temporary allowlist for
29 /* clients that have passed a number of tests. When an SMTP
30 /* client IP address is allowlisted, \fBpostscreen\fR(8) hands
31 /* off the connection immediately to a Postfix SMTP server
32 /* process. This minimizes the overhead for legitimate mail.
33 /*
34 /* By default, \fBpostscreen\fR(8) logs statistics and hands
35 /* off each connection to a Postfix SMTP server process, while
36 /* excluding clients in mynetworks from all tests (primarily,
37 /* to avoid problems with non-standard SMTP implementations
38 /* in network appliances). This default mode blocks no clients,
39 /* and is useful for non-destructive testing.
40 /*
41 /* In a typical production setting, \fBpostscreen\fR(8) is
42 /* configured to reject mail from clients that fail one or
43 /* more tests. \fBpostscreen\fR(8) logs rejected mail with the
44 /* client address, helo, sender and recipient information.
45 /*
46 /* \fBpostscreen\fR(8) is not an SMTP proxy; this is intentional.
47 /* The purpose is to keep spambots away from Postfix SMTP
48 /* server processes, while minimizing overhead for legitimate
49 /* traffic.
50 /* SECURITY
51 /* .ad
52 /* .fi
53 /* The \fBpostscreen\fR(8) server is moderately security-sensitive.
54 /* It talks to untrusted clients on the network. The process
55 /* can be run chrooted at fixed low privilege.
56 /* STANDARDS
57 /* RFC 821 (SMTP protocol)
58 /* RFC 1123 (Host requirements)
59 /* RFC 1652 (8bit-MIME transport)
60 /* RFC 1869 (SMTP service extensions)
61 /* RFC 1870 (Message Size Declaration)
62 /* RFC 1985 (ETRN command)
63 /* RFC 2034 (SMTP Enhanced Status Codes)
64 /* RFC 2821 (SMTP protocol)
65 /* Not: RFC 2920 (SMTP Pipelining)
66 /* RFC 3030 (CHUNKING without BINARYMIME)
67 /* RFC 3207 (STARTTLS command)
68 /* RFC 3461 (SMTP DSN Extension)
69 /* RFC 3463 (Enhanced Status Codes)
70 /* RFC 5321 (SMTP protocol, including multi-line 220 banners)
71 /* DIAGNOSTICS
72 /* Problems and transactions are logged to \fBsyslogd\fR(8)
73 /* or \fBpostlogd\fR(8).
74 /* BUGS
75 /* The \fBpostscreen\fR(8) built-in SMTP protocol engine
76 /* currently does not announce support for AUTH, XCLIENT or
77 /* XFORWARD.
78 /* If you need to make these services available
79 /* on port 25, then do not enable the optional "after 220
80 /* server greeting" tests.
81 /*
82 /* The optional "after 220 server greeting" tests may result in
83 /* unexpected delivery delays from senders that retry email delivery
84 /* from a different IP address. Reason: after passing these tests a
85 /* new client must disconnect, and reconnect from the same IP
86 /* address before it can deliver mail. See POSTSCREEN_README, section
87 /* "Tests after the 220 SMTP server greeting", for a discussion.
88 /* CONFIGURATION PARAMETERS
89 /* .ad
90 /* .fi
91 /* Changes to main.cf are not picked up automatically, as
92 /* \fBpostscreen\fR(8) processes may run for several hours.
93 /* Use the command "postfix reload" after a configuration
94 /* change.
95 /*
96 /* The text below provides only a parameter summary. See
97 /* \fBpostconf\fR(5) for more details including examples.
98 /*
99 /* NOTE: Some \fBpostscreen\fR(8) parameters implement
100 /* stress-dependent behavior. This is supported only when the
101 /* default parameter value is stress-dependent (that is, it
102 /* looks like ${stress?{X}:{Y}}, or it is the $\fIname\fR
103 /* of an smtpd parameter with a stress-dependent default).
104 /* Other parameters always evaluate as if the \fBstress\fR
105 /* parameter value is the empty string.
106 /* COMPATIBILITY CONTROLS
107 /* .ad
108 /* .fi
109 /* .IP "\fBpostscreen_command_filter ($smtpd_command_filter)\fR"
110 /* A mechanism to transform commands from remote SMTP clients.
111 /* .IP "\fBpostscreen_discard_ehlo_keyword_address_maps ($smtpd_discard_ehlo_keyword_address_maps)\fR"
112 /* Lookup tables, indexed by the remote SMTP client address, with
113 /* case insensitive lists of EHLO keywords (pipelining, starttls, auth,
114 /* etc.) that the \fBpostscreen\fR(8) server will not send in the EHLO response
115 /* to a remote SMTP client.
116 /* .IP "\fBpostscreen_discard_ehlo_keywords ($smtpd_discard_ehlo_keywords)\fR"
117 /* A case insensitive list of EHLO keywords (pipelining, starttls,
118 /* auth, etc.) that the \fBpostscreen\fR(8) server will not send in the EHLO
119 /* response to a remote SMTP client.
120 /* .PP
121 /* Available in Postfix version 3.1 and later:
122 /* .IP "\fBdns_ncache_ttl_fix_enable (no)\fR"
123 /* Enable a workaround for future libc incompatibility.
124 /* .PP
125 /* Available in Postfix version 3.4 and later:
126 /* .IP "\fBpostscreen_reject_footer_maps ($smtpd_reject_footer_maps)\fR"
127 /* Optional lookup table for information that is appended after a 4XX
128 /* or 5XX \fBpostscreen\fR(8) server response.
129 /* .PP
130 /* Available in Postfix 3.6 and later:
131 /* .IP "\fBrespectful_logging (see 'postconf -d' output)\fR"
132 /* Avoid logging that implies white is better than black.
133 /* TROUBLE SHOOTING CONTROLS
134 /* .ad
135 /* .fi
136 /* .IP "\fBpostscreen_expansion_filter (see 'postconf -d' output)\fR"
137 /* List of characters that are permitted in postscreen_reject_footer
138 /* attribute expansions.
139 /* .IP "\fBpostscreen_reject_footer ($smtpd_reject_footer)\fR"
140 /* Optional information that is appended after a 4XX or 5XX
141 /* \fBpostscreen\fR(8) server
142 /* response.
143 /* .IP "\fBsoft_bounce (no)\fR"
144 /* Safety net to keep mail queued that would otherwise be returned to
145 /* the sender.
146 /* BEFORE-POSTSCREEN PROXY AGENT
147 /* .ad
148 /* .fi
149 /* Available in Postfix version 2.10 and later:
150 /* .IP "\fBpostscreen_upstream_proxy_protocol (empty)\fR"
151 /* The name of the proxy protocol used by an optional before-postscreen
152 /* proxy agent.
153 /* .IP "\fBpostscreen_upstream_proxy_timeout (5s)\fR"
154 /* The time limit for the proxy protocol specified with the
155 /* postscreen_upstream_proxy_protocol parameter.
156 /* PERMANENT ALLOW/DENYLIST TEST
157 /* .ad
158 /* .fi
159 /* This test is executed immediately after a remote SMTP client
160 /* connects. If a client is permanently allowlisted, the client
161 /* will be handed off immediately to a Postfix SMTP server
162 /* process.
163 /* .IP "\fBpostscreen_access_list (permit_mynetworks)\fR"
164 /* Permanent allow/denylist for remote SMTP client IP addresses.
165 /* .IP "\fBpostscreen_blacklist_action (ignore)\fR"
166 /* Renamed to postscreen_denylist_action in Postfix 3.6.
167 /* MAIL EXCHANGER POLICY TESTS
168 /* .ad
169 /* .fi
170 /* When \fBpostscreen\fR(8) is configured to monitor all primary
171 /* and backup MX addresses, it can refuse to allowlist clients
172 /* that connect to a backup MX address only. For small sites,
173 /* this requires configuring primary and backup MX addresses
174 /* on the same MTA. Larger sites would have to share the
175 /* \fBpostscreen\fR(8) cache between primary and backup MTAs,
176 /* which would introduce a common point of failure.
177 /* .IP "\fBpostscreen_whitelist_interfaces (static:all)\fR"
178 /* Renamed to postscreen_allowlist_interfaces in Postfix 3.6.
179 /* BEFORE 220 GREETING TESTS
180 /* .ad
181 /* .fi
182 /* These tests are executed before the remote SMTP client
183 /* receives the "220 servername" greeting. If no tests remain
184 /* after the successful completion of this phase, the client
185 /* will be handed off immediately to a Postfix SMTP server
186 /* process.
187 /* .IP "\fBdnsblog_service_name (dnsblog)\fR"
188 /* The name of the \fBdnsblog\fR(8) service entry in master.cf.
189 /* .IP "\fBpostscreen_dnsbl_action (ignore)\fR"
190 /* The action that \fBpostscreen\fR(8) takes when a remote SMTP client's combined
191 /* DNSBL score is equal to or greater than a threshold (as defined
192 /* with the postscreen_dnsbl_sites and postscreen_dnsbl_threshold
193 /* parameters).
194 /* .IP "\fBpostscreen_dnsbl_reply_map (empty)\fR"
195 /* A mapping from actual DNSBL domain name which includes a secret
196 /* password, to the DNSBL domain name that postscreen will reply with
197 /* when it rejects mail.
198 /* .IP "\fBpostscreen_dnsbl_sites (empty)\fR"
199 /* Optional list of DNS allow/denylist domains, filters and weight
200 /* factors.
201 /* .IP "\fBpostscreen_dnsbl_threshold (1)\fR"
202 /* The inclusive lower bound for blocking a remote SMTP client, based on
203 /* its combined DNSBL score as defined with the postscreen_dnsbl_sites
204 /* parameter.
205 /* .IP "\fBpostscreen_greet_action (ignore)\fR"
206 /* The action that \fBpostscreen\fR(8) takes when a remote SMTP client speaks
207 /* before its turn within the time specified with the postscreen_greet_wait
208 /* parameter.
209 /* .IP "\fBpostscreen_greet_banner ($smtpd_banner)\fR"
210 /* The \fItext\fR in the optional "220-\fItext\fR..." server
211 /* response that
212 /* \fBpostscreen\fR(8) sends ahead of the real Postfix SMTP server's "220
213 /* text..." response, in an attempt to confuse bad SMTP clients so
214 /* that they speak before their turn (pre-greet).
215 /* .IP "\fBpostscreen_greet_wait (normal: 6s, overload: 2s)\fR"
216 /* The amount of time that \fBpostscreen\fR(8) will wait for an SMTP
217 /* client to send a command before its turn, and for DNS blocklist
218 /* lookup results to arrive (default: up to 2 seconds under stress,
219 /* up to 6 seconds otherwise).
220 /* .IP "\fBsmtpd_service_name (smtpd)\fR"
221 /* The internal service that \fBpostscreen\fR(8) hands off allowed
222 /* connections to.
223 /* .PP
224 /* Available in Postfix version 2.11 and later:
225 /* .IP "\fBpostscreen_dnsbl_whitelist_threshold (0)\fR"
226 /* Renamed to postscreen_dnsbl_allowlist_threshold in Postfix 3.6.
227 /* .PP
228 /* Available in Postfix version 3.0 and later:
229 /* .IP "\fBpostscreen_dnsbl_timeout (10s)\fR"
230 /* The time limit for DNSBL or DNSWL lookups.
231 /* .PP
232 /* Available in Postfix version 3.6 and later:
233 /* .IP "\fBpostscreen_denylist_action (ignore)\fR"
234 /* The action that \fBpostscreen\fR(8) takes when a remote SMTP client is
235 /* permanently denylisted with the postscreen_access_list parameter.
236 /* .IP "\fBpostscreen_allowlist_interfaces (static:all)\fR"
237 /* A list of local \fBpostscreen\fR(8) server IP addresses where a
238 /* non-allowlisted remote SMTP client can obtain \fBpostscreen\fR(8)'s temporary
239 /* allowlist status.
240 /* .IP "\fBpostscreen_dnsbl_allowlist_threshold (0)\fR"
241 /* Allow a remote SMTP client to skip "before" and "after 220
242 /* greeting" protocol tests, based on its combined DNSBL score as
243 /* defined with the postscreen_dnsbl_sites parameter.
244 /* AFTER 220 GREETING TESTS
245 /* .ad
246 /* .fi
247 /* These tests are executed after the remote SMTP client
248 /* receives the "220 servername" greeting. If a client passes
249 /* all tests during this phase, it will receive a 4XX response
250 /* to all RCPT TO commands. After the client reconnects, it
251 /* will be allowed to talk directly to a Postfix SMTP server
252 /* process.
253 /* .IP "\fBpostscreen_bare_newline_action (ignore)\fR"
254 /* The action that \fBpostscreen\fR(8) takes when a remote SMTP client sends
255 /* a bare newline character, that is, a newline not preceded by carriage
256 /* return.
257 /* .IP "\fBpostscreen_bare_newline_enable (no)\fR"
258 /* Enable "bare newline" SMTP protocol tests in the \fBpostscreen\fR(8)
259 /* server.
260 /* .IP "\fBpostscreen_disable_vrfy_command ($disable_vrfy_command)\fR"
261 /* Disable the SMTP VRFY command in the \fBpostscreen\fR(8) daemon.
262 /* .IP "\fBpostscreen_forbidden_commands ($smtpd_forbidden_commands)\fR"
263 /* List of commands that the \fBpostscreen\fR(8) server considers in
264 /* violation of the SMTP protocol.
265 /* .IP "\fBpostscreen_helo_required ($smtpd_helo_required)\fR"
266 /* Require that a remote SMTP client sends HELO or EHLO before
267 /* commencing a MAIL transaction.
268 /* .IP "\fBpostscreen_non_smtp_command_action (drop)\fR"
269 /* The action that \fBpostscreen\fR(8) takes when a remote SMTP client sends
270 /* non-SMTP commands as specified with the postscreen_forbidden_commands
271 /* parameter.
272 /* .IP "\fBpostscreen_non_smtp_command_enable (no)\fR"
273 /* Enable "non-SMTP command" tests in the \fBpostscreen\fR(8) server.
274 /* .IP "\fBpostscreen_pipelining_action (enforce)\fR"
275 /* The action that \fBpostscreen\fR(8) takes when a remote SMTP client
276 /* sends
277 /* multiple commands instead of sending one command and waiting for
278 /* the server to respond.
279 /* .IP "\fBpostscreen_pipelining_enable (no)\fR"
280 /* Enable "pipelining" SMTP protocol tests in the \fBpostscreen\fR(8)
281 /* server.
282 /* CACHE CONTROLS
283 /* .ad
284 /* .fi
285 /* .IP "\fBpostscreen_cache_cleanup_interval (12h)\fR"
286 /* The amount of time between \fBpostscreen\fR(8) cache cleanup runs.
287 /* .IP "\fBpostscreen_cache_map (btree:$data_directory/postscreen_cache)\fR"
288 /* Persistent storage for the \fBpostscreen\fR(8) server decisions.
289 /* .IP "\fBpostscreen_cache_retention_time (7d)\fR"
290 /* The amount of time that \fBpostscreen\fR(8) will cache an expired
291 /* temporary allowlist entry before it is removed.
292 /* .IP "\fBpostscreen_bare_newline_ttl (30d)\fR"
293 /* The amount of time that \fBpostscreen\fR(8) will use the result from
294 /* a successful "bare newline" SMTP protocol test.
295 /* .IP "\fBpostscreen_dnsbl_max_ttl (${postscreen_dnsbl_ttl?{$postscreen_dnsbl_ttl}:{1}}h)\fR"
296 /* The maximum amount of time that \fBpostscreen\fR(8) will use the
297 /* result from a successful DNS-based reputation test before a
298 /* client IP address is required to pass that test again.
299 /* .IP "\fBpostscreen_dnsbl_min_ttl (60s)\fR"
300 /* The minimum amount of time that \fBpostscreen\fR(8) will use the
301 /* result from a successful DNS-based reputation test before a
302 /* client IP address is required to pass that test again.
303 /* .IP "\fBpostscreen_greet_ttl (1d)\fR"
304 /* The amount of time that \fBpostscreen\fR(8) will use the result from
305 /* a successful PREGREET test.
306 /* .IP "\fBpostscreen_non_smtp_command_ttl (30d)\fR"
307 /* The amount of time that \fBpostscreen\fR(8) will use the result from
308 /* a successful "non_smtp_command" SMTP protocol test.
309 /* .IP "\fBpostscreen_pipelining_ttl (30d)\fR"
310 /* The amount of time that \fBpostscreen\fR(8) will use the result from
311 /* a successful "pipelining" SMTP protocol test.
312 /* RESOURCE CONTROLS
313 /* .ad
314 /* .fi
315 /* .IP "\fBline_length_limit (2048)\fR"
316 /* Upon input, long lines are chopped up into pieces of at most
317 /* this length; upon delivery, long lines are reconstructed.
318 /* .IP "\fBpostscreen_client_connection_count_limit ($smtpd_client_connection_count_limit)\fR"
319 /* How many simultaneous connections any remote SMTP client is
320 /* allowed to have
321 /* with the \fBpostscreen\fR(8) daemon.
322 /* .IP "\fBpostscreen_command_count_limit (20)\fR"
323 /* The limit on the total number of commands per SMTP session for
324 /* \fBpostscreen\fR(8)'s built-in SMTP protocol engine.
325 /* .IP "\fBpostscreen_command_time_limit (normal: 300s, overload: 10s)\fR"
326 /* The time limit to read an entire command line with \fBpostscreen\fR(8)'s
327 /* built-in SMTP protocol engine.
328 /* .IP "\fBpostscreen_post_queue_limit ($default_process_limit)\fR"
329 /* The number of clients that can be waiting for service from a
330 /* real Postfix SMTP server process.
331 /* .IP "\fBpostscreen_pre_queue_limit ($default_process_limit)\fR"
332 /* The number of non-allowlisted clients that can be waiting for
333 /* a decision whether they will receive service from a real Postfix
334 /* SMTP server
335 /* process.
336 /* .IP "\fBpostscreen_watchdog_timeout (10s)\fR"
337 /* How much time a \fBpostscreen\fR(8) process may take to respond to
338 /* a remote SMTP client command or to perform a cache operation before it
339 /* is terminated by a built-in watchdog timer.
340 /* STARTTLS CONTROLS
341 /* .ad
342 /* .fi
343 /* .IP "\fBpostscreen_tls_security_level ($smtpd_tls_security_level)\fR"
344 /* The SMTP TLS security level for the \fBpostscreen\fR(8) server; when
345 /* a non-empty value is specified, this overrides the obsolete parameters
346 /* postscreen_use_tls and postscreen_enforce_tls.
347 /* .IP "\fBtlsproxy_service_name (tlsproxy)\fR"
348 /* The name of the \fBtlsproxy\fR(8) service entry in master.cf.
349 /* OBSOLETE STARTTLS SUPPORT CONTROLS
350 /* .ad
351 /* .fi
352 /* These parameters are supported for compatibility with
353 /* \fBsmtpd\fR(8) legacy parameters.
354 /* .IP "\fBpostscreen_use_tls ($smtpd_use_tls)\fR"
355 /* Opportunistic TLS: announce STARTTLS support to remote SMTP clients,
356 /* but do not require that clients use TLS encryption.
357 /* .IP "\fBpostscreen_enforce_tls ($smtpd_enforce_tls)\fR"
358 /* Mandatory TLS: announce STARTTLS support to remote SMTP clients, and
359 /* require that clients use TLS encryption.
360 /* MISCELLANEOUS CONTROLS
361 /* .ad
362 /* .fi
363 /* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
364 /* The default location of the Postfix main.cf and master.cf
365 /* configuration files.
366 /* .IP "\fBdelay_logging_resolution_limit (2)\fR"
367 /* The maximal number of digits after the decimal point when logging
368 /* sub-second delay values.
369 /* .IP "\fBcommand_directory (see 'postconf -d' output)\fR"
370 /* The location of all postfix administrative commands.
371 /* .IP "\fBmax_idle (100s)\fR"
372 /* The maximum amount of time that an idle Postfix daemon process waits
373 /* for an incoming connection before terminating voluntarily.
374 /* .IP "\fBprocess_id (read-only)\fR"
375 /* The process ID of a Postfix command or daemon process.
376 /* .IP "\fBprocess_name (read-only)\fR"
377 /* The process name of a Postfix command or daemon process.
378 /* .IP "\fBsyslog_facility (mail)\fR"
379 /* The syslog facility of Postfix logging.
380 /* .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
381 /* A prefix that is prepended to the process name in syslog
382 /* records, so that, for example, "smtpd" becomes "prefix/smtpd".
383 /* .PP
384 /* Available in Postfix 3.3 and later:
385 /* .IP "\fBservice_name (read-only)\fR"
386 /* The master.cf service name of a Postfix daemon process.
387 /* .PP
388 /* Available in Postfix 3.5 and later:
389 /* .IP "\fBinfo_log_address_format (external)\fR"
390 /* The email address form that will be used in non-debug logging
391 /* (info, warning, etc.).
392 /* SEE ALSO
393 /* smtpd(8), Postfix SMTP server
394 /* tlsproxy(8), Postfix TLS proxy server
395 /* dnsblog(8), DNS allow/denylist logger
396 /* postlogd(8), Postfix logging
397 /* syslogd(8), system logging
398 /* README FILES
399 /* .ad
400 /* .fi
401 /* Use "\fBpostconf readme_directory\fR" or "\fBpostconf
402 /* html_directory\fR" to locate this information.
403 /* .nf
404 /* .na
405 /* POSTSCREEN_README, Postfix Postscreen Howto
406 /* LICENSE
407 /* .ad
408 /* .fi
409 /* The Secure Mailer license must be distributed with this software.
410 /* HISTORY
411 /* .ad
412 /* .fi
413 /* This service was introduced with Postfix version 2.8.
414 /*
415 /* Many ideas in \fBpostscreen\fR(8) were explored in earlier
416 /* work by Michael Tokarev, in OpenBSD spamd, and in MailChannels
417 /* Traffic Control.
418 /* AUTHOR(S)
419 /* Wietse Venema
420 /* IBM T.J. Watson Research
421 /* P.O. Box 704
422 /* Yorktown Heights, NY 10598, USA
423 /*
424 /* Wietse Venema
425 /* Google, Inc.
426 /* 111 8th Avenue
427 /* New York, NY 10011, USA
428 /*--*/
429
430 /* System library. */
431
432 #include <sys_defs.h>
433 #include <sys/stat.h>
434 #include <stdlib.h>
435
436 /* Utility library. */
437
438 #include <msg.h>
439 #include <mymalloc.h>
440 #include <events.h>
441 #include <myaddrinfo.h>
442 #include <dict_cache.h>
443 #include <set_eugid.h>
444 #include <vstream.h>
445 #include <name_code.h>
446 #include <inet_proto.h>
447
448 /* Global library. */
449
450 #include <mail_conf.h>
451 #include <mail_params.h>
452 #include <mail_version.h>
453 #include <mail_proto.h>
454 #include <data_redirect.h>
455 #include <string_list.h>
456
457 /* Master server protocols. */
458
459 #include <mail_server.h>
460
461 /* Application-specific. */
462
463 #include <postscreen.h>
464
465 /*
466 * Configuration parameters.
467 */
468 char *var_smtpd_service;
469 char *var_smtpd_banner;
470 bool var_disable_vrfy_cmd;
471 bool var_helo_required;
472
473 char *var_smtpd_cmd_filter;
474 char *var_psc_cmd_filter;
475
476 char *var_smtpd_forbid_cmds;
477 char *var_psc_forbid_cmds;
478
479 char *var_smtpd_ehlo_dis_words;
480 char *var_smtpd_ehlo_dis_maps;
481 char *var_psc_ehlo_dis_words;
482 char *var_psc_ehlo_dis_maps;
483
484 char *var_smtpd_tls_level;
485 bool var_smtpd_use_tls;
486 bool var_smtpd_enforce_tls;
487 char *var_psc_tls_level;
488 bool var_psc_use_tls;
489 bool var_psc_enforce_tls;
490
491 bool var_psc_disable_vrfy;
492 bool var_psc_helo_required;
493
494 char *var_psc_cache_map;
495 int var_psc_cache_scan;
496 int var_psc_cache_ret;
497 int var_psc_post_queue_limit;
498 int var_psc_pre_queue_limit;
499 int var_psc_watchdog;
500
501 char *var_psc_acl;
502 char *var_psc_dnlist_action;
503
504 char *var_psc_greet_ttl;
505 int var_psc_greet_wait;
506
507 char *var_psc_pregr_banner;
508 char *var_psc_pregr_action;
509 int var_psc_pregr_ttl;
510
511 char *var_psc_dnsbl_sites;
512 char *var_psc_dnsbl_reply;
513 int var_psc_dnsbl_thresh;
514 int var_psc_dnsbl_althresh;
515 char *var_psc_dnsbl_action;
516 int var_psc_dnsbl_min_ttl;
517 int var_psc_dnsbl_max_ttl;
518 int var_psc_dnsbl_tmout;
519
520 bool var_psc_pipel_enable;
521 char *var_psc_pipel_action;
522 int var_psc_pipel_ttl;
523
524 bool var_psc_nsmtp_enable;
525 char *var_psc_nsmtp_action;
526 int var_psc_nsmtp_ttl;
527
528 bool var_psc_barlf_enable;
529 char *var_psc_barlf_action;
530 int var_psc_barlf_ttl;
531
532 int var_psc_cmd_count;
533 int var_psc_cmd_time;
534
535 char *var_dnsblog_service;
536 char *var_tlsproxy_service;
537
538 char *var_smtpd_rej_footer;
539 char *var_psc_rej_footer;
540 char *var_psc_rej_ftr_maps;
541
542 int var_smtpd_cconn_limit;
543 int var_psc_cconn_limit;
544
545 char *var_smtpd_exp_filter;
546 char *var_psc_exp_filter;
547
548 char *var_psc_allist_if;
549 char *var_psc_uproxy_proto;
550 int var_psc_uproxy_tmout;
551
552 /*
553 * Global variables.
554 */
555 int psc_check_queue_length; /* connections being checked */
556 int psc_post_queue_length; /* being sent to real SMTPD */
557 DICT_CACHE *psc_cache_map; /* cache table handle */
558 VSTRING *psc_temp; /* scratchpad */
559 char *psc_smtpd_service_name; /* path to real SMTPD */
560 int psc_pregr_action; /* PSC_ACT_DROP/ENFORCE/etc */
561 int psc_dnsbl_action; /* PSC_ACT_DROP/ENFORCE/etc */
562 int psc_pipel_action; /* PSC_ACT_DROP/ENFORCE/etc */
563 int psc_nsmtp_action; /* PSC_ACT_DROP/ENFORCE/etc */
564 int psc_barlf_action; /* PSC_ACT_DROP/ENFORCE/etc */
565 int psc_min_ttl; /* Update with new tests! */
566 STRING_LIST *psc_forbid_cmds; /* CONNECT GET POST */
567 int psc_stress_greet_wait; /* stressed greet wait */
568 int psc_normal_greet_wait; /* stressed greet wait */
569 int psc_stress_cmd_time_limit; /* stressed command limit */
570 int psc_normal_cmd_time_limit; /* normal command time limit */
571 int psc_stress; /* stress level */
572 int psc_lowat_check_queue_length; /* stress low-water mark */
573 int psc_hiwat_check_queue_length; /* stress high-water mark */
574 DICT *psc_dnsbl_reply; /* DNSBL name mapper */
575 HTABLE *psc_client_concurrency; /* per-client concurrency */
576
577 /*
578 * Local variables and functions.
579 */
580 static ARGV *psc_acl; /* permanent allow/denylist */
581 static int psc_dnlist_action; /* PSC_ACT_DROP/ENFORCE/etc */
582 static ADDR_MATCH_LIST *psc_allist_if; /* allowlist interfaces */
583
584 static void psc_endpt_lookup_done(int, VSTREAM *,
585 MAI_HOSTADDR_STR *, MAI_SERVPORT_STR *,
586 MAI_HOSTADDR_STR *, MAI_SERVPORT_STR *);
587
588 /* psc_dump - dump some statistics before exit */
589
psc_dump(char * unused_service,char ** unused_argv)590 static void psc_dump(char *unused_service, char **unused_argv)
591 {
592
593 /*
594 * Dump preliminary cache cleanup statistics when the process commits
595 * suicide while a cache cleanup run is in progress. We can't currently
596 * distinguish between "postfix reload" (we should restart) or "maximal
597 * idle time reached" (we could finish the cache cleanup first).
598 */
599 if (psc_cache_map) {
600 dict_cache_close(psc_cache_map);
601 psc_cache_map = 0;
602 }
603 }
604
605 /* psc_drain - delayed exit after "postfix reload" */
606
psc_drain(char * unused_service,char ** unused_argv)607 static void psc_drain(char *unused_service, char **unused_argv)
608 {
609 int count;
610
611 /*
612 * After "postfix reload", complete work-in-progress in the background,
613 * instead of dropping already-accepted connections on the floor.
614 *
615 * Unfortunately we must close all writable tables, so we can't store or
616 * look up reputation information. The reason is that we don't have any
617 * multi-writer safety guarantees. We also can't use the single-writer
618 * proxywrite service, because its latency guarantees are too weak.
619 *
620 * All error retry counts shall be limited. Instead of blocking here, we
621 * could retry failed fork() operations in the event call-back routines,
622 * but we don't need perfection. The host system is severely overloaded
623 * and service levels are already way down.
624 *
625 * XXX Some Berkeley DB versions break with close-after-fork. Every new
626 * version is an improvement over its predecessor.
627 *
628 * XXX Don't assume that it is OK to share the same LMDB lockfile descriptor
629 * between different processes.
630 */
631 if (psc_cache_map != 0 /* XXX && psc_cache_map
632 requires locking */ ) {
633 dict_cache_close(psc_cache_map);
634 psc_cache_map = 0;
635 }
636 for (count = 0; /* see below */ ; count++) {
637 if (count >= 5) {
638 msg_fatal("fork: %m");
639 } else if (event_server_drain() != 0) {
640 msg_warn("fork: %m");
641 sleep(1);
642 continue;
643 } else {
644 return;
645 }
646 }
647 }
648
649 /* psc_service - handle new client connection */
650
psc_service(VSTREAM * smtp_client_stream,char * unused_service,char ** unused_argv)651 static void psc_service(VSTREAM *smtp_client_stream,
652 char *unused_service,
653 char **unused_argv)
654 {
655
656 /*
657 * For sanity, require that at least one of INET or INET6 is enabled.
658 * Otherwise, we can't look up interface information, and we can't
659 * convert names or addresses.
660 */
661 if (inet_proto_info()->ai_family_list[0] == 0)
662 msg_fatal("all network protocols are disabled (%s = %s)",
663 VAR_INET_PROTOCOLS, var_inet_protocols);
664
665 /*
666 * This program handles all incoming connections, so it must not block.
667 * We use event-driven code for all operations that introduce latency.
668 *
669 * Note: instead of using VSTREAM-level timeouts, we enforce limits on the
670 * total amount of time to receive a complete SMTP command line.
671 */
672 non_blocking(vstream_fileno(smtp_client_stream), NON_BLOCKING);
673
674 /*
675 * Look up the remote SMTP client address and port.
676 */
677 psc_endpt_lookup(smtp_client_stream, psc_endpt_lookup_done);
678 }
679
680 /* psc_warn_compat_respectful_logging - compatibility warning */
681
psc_warn_compat_respectful_logging(PSC_STATE * state)682 static void psc_warn_compat_respectful_logging(PSC_STATE *state)
683 {
684 msg_info("using backwards-compatible default setting "
685 VAR_RESPECTFUL_LOGGING "=no for client [%s]:%s",
686 PSC_CLIENT_ADDR_PORT(state));
687 warn_compat_respectful_logging = 0;
688 }
689
690 /* psc_endpt_lookup_done - endpoint lookup completed */
691
psc_endpt_lookup_done(int endpt_status,VSTREAM * smtp_client_stream,MAI_HOSTADDR_STR * smtp_client_addr,MAI_SERVPORT_STR * smtp_client_port,MAI_HOSTADDR_STR * smtp_server_addr,MAI_SERVPORT_STR * smtp_server_port)692 static void psc_endpt_lookup_done(int endpt_status,
693 VSTREAM *smtp_client_stream,
694 MAI_HOSTADDR_STR *smtp_client_addr,
695 MAI_SERVPORT_STR *smtp_client_port,
696 MAI_HOSTADDR_STR *smtp_server_addr,
697 MAI_SERVPORT_STR *smtp_server_port)
698 {
699 const char *myname = "psc_endpt_lookup_done";
700 PSC_STATE *state;
701 const char *stamp_str;
702 int saved_flags;
703
704 /*
705 * Best effort - if this non-blocking write(2) fails, so be it.
706 */
707 if (endpt_status < 0) {
708 (void) write(vstream_fileno(smtp_client_stream),
709 "421 4.3.2 No system resources\r\n",
710 sizeof("421 4.3.2 No system resources\r\n") - 1);
711 event_server_disconnect(smtp_client_stream);
712 return;
713 }
714 if (msg_verbose > 1)
715 msg_info("%s: sq=%d cq=%d connect from [%s]:%s",
716 myname, psc_post_queue_length, psc_check_queue_length,
717 smtp_client_addr->buf, smtp_client_port->buf);
718
719 msg_info("CONNECT from [%s]:%s to [%s]:%s",
720 smtp_client_addr->buf, smtp_client_port->buf,
721 smtp_server_addr->buf, smtp_server_port->buf);
722
723 /*
724 * Bundle up all the loose session pieces. This zeroes all flags and time
725 * stamps.
726 */
727 state = psc_new_session_state(smtp_client_stream, smtp_client_addr->buf,
728 smtp_client_port->buf,
729 smtp_server_addr->buf,
730 smtp_server_port->buf);
731
732 /*
733 * Reply with 421 when the client has too many open connections.
734 */
735 if (var_psc_cconn_limit > 0
736 && state->client_info->concurrency > var_psc_cconn_limit) {
737 msg_info("NOQUEUE: reject: CONNECT from [%s]:%s: too many connections",
738 state->smtp_client_addr, state->smtp_client_port);
739 PSC_DROP_SESSION_STATE(state,
740 "421 4.7.0 Error: too many connections\r\n");
741 return;
742 }
743
744 /*
745 * Reply with 421 when we can't forward more connections.
746 */
747 if (var_psc_post_queue_limit > 0
748 && psc_post_queue_length >= var_psc_post_queue_limit) {
749 msg_info("NOQUEUE: reject: CONNECT from [%s]:%s: all server ports busy",
750 state->smtp_client_addr, state->smtp_client_port);
751 PSC_DROP_SESSION_STATE(state,
752 "421 4.3.2 All server ports are busy\r\n");
753 return;
754 }
755
756 /*
757 * The permanent allow/denylist has highest precedence.
758 */
759 if (psc_acl != 0) {
760 switch (psc_acl_eval(state, psc_acl, VAR_PSC_ACL)) {
761
762 /*
763 * Permanently denylisted.
764 */
765 case PSC_ACL_ACT_DENYLIST:
766 msg_info("%sLISTED [%s]:%s",
767 var_respectful_logging ? "DENY" : "BLACK",
768 PSC_CLIENT_ADDR_PORT(state));
769 if (warn_compat_respectful_logging)
770 psc_warn_compat_respectful_logging(state);
771 PSC_FAIL_SESSION_STATE(state, PSC_STATE_FLAG_DNLIST_FAIL);
772 switch (psc_dnlist_action) {
773 case PSC_ACT_DROP:
774 PSC_DROP_SESSION_STATE(state,
775 "521 5.3.2 Service currently unavailable\r\n");
776 return;
777 case PSC_ACT_ENFORCE:
778 PSC_ENFORCE_SESSION_STATE(state,
779 "550 5.3.2 Service currently unavailable\r\n");
780 break;
781 case PSC_ACT_IGNORE:
782 PSC_UNFAIL_SESSION_STATE(state, PSC_STATE_FLAG_DNLIST_FAIL);
783
784 /*
785 * Not: PSC_PASS_SESSION_STATE. Repeat this test the next
786 * time.
787 */
788 break;
789 default:
790 msg_panic("%s: unknown denylist action value %d",
791 myname, psc_dnlist_action);
792 }
793 break;
794
795 /*
796 * Permanently allowlisted.
797 */
798 case PSC_ACL_ACT_ALLOWLIST:
799 msg_info("%sLISTED [%s]:%s",
800 var_respectful_logging ? "ALLOW" : "WHITE",
801 PSC_CLIENT_ADDR_PORT(state));
802 if (warn_compat_respectful_logging)
803 psc_warn_compat_respectful_logging(state);
804 psc_conclude(state);
805 return;
806
807 /*
808 * Other: dunno (don't know) or error.
809 */
810 default:
811 break;
812 }
813 }
814
815 /*
816 * The temporary allowlist (i.e. the postscreen cache) has the lowest
817 * precedence. This cache contains information about the results of prior
818 * tests. Allowlist the client when all enabled test results are still
819 * valid.
820 */
821 if ((state->flags & PSC_STATE_MASK_ANY_FAIL) == 0
822 && state->client_info->concurrency == 1
823 && psc_cache_map != 0
824 && (stamp_str = psc_cache_lookup(psc_cache_map, state->smtp_client_addr)) != 0) {
825 saved_flags = state->flags;
826 psc_parse_tests(state, stamp_str, event_time());
827 state->flags |= saved_flags;
828 if (msg_verbose)
829 msg_info("%s: cached + recent flags: %s",
830 myname, psc_print_state_flags(state->flags, myname));
831 if ((state->flags & PSC_STATE_MASK_ANY_TODO_FAIL) == 0) {
832 msg_info("PASS OLD [%s]:%s", PSC_CLIENT_ADDR_PORT(state));
833 psc_conclude(state);
834 return;
835 }
836 } else if (state->client_info->concurrency > 1) {
837 saved_flags = state->flags;
838 psc_todo_tests(state, event_time());
839 state->flags |= saved_flags;
840 if (msg_verbose)
841 msg_info("%s: new + recent flags: %s",
842 myname, psc_print_state_flags(state->flags, myname));
843 } else {
844 saved_flags = state->flags;
845 psc_new_tests(state);
846 state->flags |= saved_flags;
847 if (msg_verbose)
848 msg_info("%s: new + recent flags: %s",
849 myname, psc_print_state_flags(state->flags, myname));
850 }
851
852 /*
853 * Don't allowlist clients that connect to backup MX addresses. Fail
854 * "closed" on error.
855 */
856 if (addr_match_list_match(psc_allist_if, smtp_server_addr->buf) == 0) {
857 state->flags |= (PSC_STATE_FLAG_ALLIST_FAIL | PSC_STATE_FLAG_NOFORWARD);
858 msg_info("%sLIST VETO [%s]:%s", var_respectful_logging ?
859 "ALLOW" : "WHITE", PSC_CLIENT_ADDR_PORT(state));
860 if (warn_compat_respectful_logging)
861 psc_warn_compat_respectful_logging(state);
862 }
863
864 /*
865 * Reply with 421 when we can't analyze more connections. That also means
866 * no deep protocol tests when the noforward flag is raised.
867 */
868 if (var_psc_pre_queue_limit > 0
869 && psc_check_queue_length - psc_post_queue_length
870 >= var_psc_pre_queue_limit) {
871 msg_info("reject: connect from [%s]:%s: all screening ports busy",
872 state->smtp_client_addr, state->smtp_client_port);
873 PSC_DROP_SESSION_STATE(state,
874 "421 4.3.2 All screening ports are busy\r\n");
875 return;
876 }
877
878 /*
879 * If the client has no up-to-date results for some tests, do those tests
880 * first. Otherwise, skip the tests and hand off the connection.
881 */
882 if (state->flags & PSC_STATE_MASK_EARLY_TODO)
883 psc_early_tests(state);
884 else if (state->flags & (PSC_STATE_MASK_SMTPD_TODO | PSC_STATE_FLAG_NOFORWARD))
885 psc_smtpd_tests(state);
886 else
887 psc_conclude(state);
888 }
889
890 /* psc_cache_validator - validate one cache entry */
891
psc_cache_validator(const char * client_addr,const char * stamp_str,void * unused_context)892 static int psc_cache_validator(const char *client_addr,
893 const char *stamp_str,
894 void *unused_context)
895 {
896 PSC_STATE dummy_state;
897 PSC_CLIENT_INFO dummy_client_info;
898
899 /*
900 * This function is called by the cache cleanup pseudo thread.
901 *
902 * When an entry is removed from the cache, the client will be reported as
903 * "NEW" in the next session where it passes all tests again. To avoid
904 * silly logging we remove the cache entry only after all tests have
905 * expired longer ago than the cache retention time.
906 */
907 dummy_state.client_info = &dummy_client_info;
908 psc_parse_tests(&dummy_state, stamp_str, event_time() - var_psc_cache_ret);
909 return ((dummy_state.flags & PSC_STATE_MASK_ANY_TODO) == 0);
910 }
911
912 /* pre_jail_init - pre-jail initialization */
913
pre_jail_init(char * unused_name,char ** unused_argv)914 static void pre_jail_init(char *unused_name, char **unused_argv)
915 {
916 VSTRING *redirect;
917
918 /*
919 * Open read-only maps before dropping privilege, for consistency with
920 * other Postfix daemons.
921 */
922 psc_acl_pre_jail_init(var_mynetworks, VAR_PSC_ACL);
923 if (*var_psc_acl)
924 psc_acl = psc_acl_parse(var_psc_acl, VAR_PSC_ACL);
925 /* Ignore smtpd_forbid_cmds lookup errors. Non-critical feature. */
926 if (*var_psc_forbid_cmds)
927 psc_forbid_cmds = string_list_init(VAR_PSC_FORBID_CMDS,
928 MATCH_FLAG_RETURN,
929 var_psc_forbid_cmds);
930 if (*var_psc_dnsbl_reply)
931 psc_dnsbl_reply = dict_open(var_psc_dnsbl_reply, O_RDONLY,
932 DICT_FLAG_DUP_WARN);
933
934 /*
935 * Never, ever, get killed by a master signal, as that would corrupt the
936 * database when we're in the middle of an update.
937 */
938 if (setsid() < 0)
939 msg_warn("setsid: %m");
940
941 /*
942 * Security: don't create root-owned files that contain untrusted data.
943 * And don't create Postfix-owned files in root-owned directories,
944 * either. We want a correct relationship between (file or directory)
945 * ownership and (file or directory) content. To open files before going
946 * to jail, temporarily drop root privileges.
947 */
948 SAVE_AND_SET_EUGID(var_owner_uid, var_owner_gid);
949 redirect = vstring_alloc(100);
950
951 /*
952 * Keep state in persistent external map. As a safety measure we sync the
953 * database on each update. This hurts on LINUX file systems that sync
954 * all dirty disk blocks whenever any application invokes fsync().
955 *
956 * Start the cache maintenance pseudo thread after dropping privileges.
957 */
958 #define PSC_DICT_OPEN_FLAGS (DICT_FLAG_DUP_REPLACE | DICT_FLAG_SYNC_UPDATE | \
959 DICT_FLAG_OPEN_LOCK)
960
961 if (*var_psc_cache_map)
962 psc_cache_map =
963 dict_cache_open(data_redirect_map(redirect, var_psc_cache_map),
964 O_CREAT | O_RDWR, PSC_DICT_OPEN_FLAGS);
965
966 /*
967 * Clean up and restore privilege.
968 */
969 vstring_free(redirect);
970 RESTORE_SAVED_EUGID();
971
972 /*
973 * Initialize the dummy SMTP engine.
974 */
975 psc_smtpd_pre_jail_init();
976 }
977
978 /* pre_accept - see if tables have changed */
979
pre_accept(char * unused_name,char ** unused_argv)980 static void pre_accept(char *unused_name, char **unused_argv)
981 {
982 static time_t last_event_time;
983 time_t new_event_time;
984 const char *name;
985
986 /*
987 * If some table has changed then stop accepting new connections. Don't
988 * check the tables more than once a second.
989 */
990 new_event_time = event_time();
991 if (new_event_time >= last_event_time + 1
992 && (name = dict_changed_name()) != 0) {
993 msg_info("table %s has changed - finishing in the background", name);
994 event_server_drain();
995 } else {
996 last_event_time = new_event_time;
997 }
998 }
999
1000 /* post_jail_init - post-jail initialization */
1001
post_jail_init(char * unused_name,char ** unused_argv)1002 static void post_jail_init(char *unused_name, char **unused_argv)
1003 {
1004 const NAME_CODE actions[] = {
1005 PSC_NAME_ACT_DROP, PSC_ACT_DROP,
1006 PSC_NAME_ACT_ENFORCE, PSC_ACT_ENFORCE,
1007 PSC_NAME_ACT_IGNORE, PSC_ACT_IGNORE,
1008 PSC_NAME_ACT_CONT, PSC_ACT_IGNORE, /* compatibility */
1009 0, -1,
1010 };
1011 int cache_flags;
1012 const char *tmp;
1013
1014 /*
1015 * This routine runs after the skeleton code has entered the chroot jail.
1016 * Prevent automatic process suicide after a limited number of client
1017 * requests. It is OK to terminate after a limited amount of idle time.
1018 */
1019 var_use_limit = 0;
1020
1021 /*
1022 * Workaround for parameters whose values may contain "$", and that have
1023 * a default of "$parametername". Not sure if it would be a good idea to
1024 * always to this in the mail_conf_raw(3) module.
1025 */
1026 if (*var_psc_rej_footer == '$'
1027 && mail_conf_lookup(var_psc_rej_footer + 1)) {
1028 tmp = mail_conf_eval_once(var_psc_rej_footer);
1029 myfree(var_psc_rej_footer);
1030 var_psc_rej_footer = mystrdup(tmp);
1031 }
1032 if (*var_psc_exp_filter == '$'
1033 && mail_conf_lookup(var_psc_exp_filter + 1)) {
1034 tmp = mail_conf_eval_once(var_psc_exp_filter);
1035 myfree(var_psc_exp_filter);
1036 var_psc_exp_filter = mystrdup(tmp);
1037 }
1038
1039 /*
1040 * Other one-time initialization.
1041 */
1042 psc_temp = vstring_alloc(10);
1043 vstring_sprintf(psc_temp, "%s/%s", MAIL_CLASS_PRIVATE, var_smtpd_service);
1044 psc_smtpd_service_name = mystrdup(STR(psc_temp));
1045 psc_dnsbl_init();
1046 psc_early_init();
1047 psc_smtpd_init();
1048
1049 if ((psc_dnlist_action = name_code(actions, NAME_CODE_FLAG_NONE,
1050 var_psc_dnlist_action)) < 0)
1051 msg_fatal("bad %s value: %s", VAR_PSC_DNLIST_ACTION,
1052 var_psc_dnlist_action);
1053 if ((psc_dnsbl_action = name_code(actions, NAME_CODE_FLAG_NONE,
1054 var_psc_dnsbl_action)) < 0)
1055 msg_fatal("bad %s value: %s", VAR_PSC_DNSBL_ACTION,
1056 var_psc_dnsbl_action);
1057 if ((psc_pregr_action = name_code(actions, NAME_CODE_FLAG_NONE,
1058 var_psc_pregr_action)) < 0)
1059 msg_fatal("bad %s value: %s", VAR_PSC_PREGR_ACTION,
1060 var_psc_pregr_action);
1061 if ((psc_pipel_action = name_code(actions, NAME_CODE_FLAG_NONE,
1062 var_psc_pipel_action)) < 0)
1063 msg_fatal("bad %s value: %s", VAR_PSC_PIPEL_ACTION,
1064 var_psc_pipel_action);
1065 if ((psc_nsmtp_action = name_code(actions, NAME_CODE_FLAG_NONE,
1066 var_psc_nsmtp_action)) < 0)
1067 msg_fatal("bad %s value: %s", VAR_PSC_NSMTP_ACTION,
1068 var_psc_nsmtp_action);
1069 if ((psc_barlf_action = name_code(actions, NAME_CODE_FLAG_NONE,
1070 var_psc_barlf_action)) < 0)
1071 msg_fatal("bad %s value: %s", VAR_PSC_BARLF_ACTION,
1072 var_psc_barlf_action);
1073 /* Fail "closed" on error. */
1074 psc_allist_if = addr_match_list_init(VAR_PSC_ALLIST_IF, MATCH_FLAG_RETURN,
1075 var_psc_allist_if);
1076
1077 /*
1078 * Start the cache maintenance pseudo thread last. Early cleanup makes
1079 * verbose logging more informative (we get positive confirmation that
1080 * the cleanup thread runs).
1081 */
1082 cache_flags = DICT_CACHE_FLAG_STATISTICS;
1083 if (msg_verbose > 1)
1084 cache_flags |= DICT_CACHE_FLAG_VERBOSE;
1085 if (psc_cache_map != 0 && var_psc_cache_scan > 0)
1086 dict_cache_control(psc_cache_map,
1087 CA_DICT_CACHE_CTL_FLAGS(cache_flags),
1088 CA_DICT_CACHE_CTL_INTERVAL(var_psc_cache_scan),
1089 CA_DICT_CACHE_CTL_VALIDATOR(psc_cache_validator),
1090 CA_DICT_CACHE_CTL_CONTEXT((void *) 0),
1091 CA_DICT_CACHE_CTL_END);
1092
1093 /*
1094 * Pre-compute the minimal and maximal TTL.
1095 */
1096 psc_min_ttl =
1097 PSC_MIN(PSC_MIN(var_psc_pregr_ttl, var_psc_dnsbl_min_ttl),
1098 PSC_MIN(PSC_MIN(var_psc_pipel_ttl, var_psc_nsmtp_ttl),
1099 var_psc_barlf_ttl));
1100
1101 /*
1102 * Pre-compute the stress and normal command time limits.
1103 */
1104 mail_conf_update(VAR_STRESS, "yes");
1105 psc_stress_cmd_time_limit =
1106 get_mail_conf_time(VAR_PSC_CMD_TIME, DEF_PSC_CMD_TIME, 1, 0);
1107 psc_stress_greet_wait =
1108 get_mail_conf_time(VAR_PSC_GREET_WAIT, DEF_PSC_GREET_WAIT, 1, 0);
1109
1110 mail_conf_update(VAR_STRESS, "");
1111 psc_normal_cmd_time_limit =
1112 get_mail_conf_time(VAR_PSC_CMD_TIME, DEF_PSC_CMD_TIME, 1, 0);
1113 psc_normal_greet_wait =
1114 get_mail_conf_time(VAR_PSC_GREET_WAIT, DEF_PSC_GREET_WAIT, 1, 0);
1115
1116 psc_lowat_check_queue_length = .7 * var_psc_pre_queue_limit;
1117 psc_hiwat_check_queue_length = .9 * var_psc_pre_queue_limit;
1118 if (msg_verbose)
1119 msg_info(VAR_PSC_CMD_TIME ": stress=%d normal=%d lowat=%d hiwat=%d",
1120 psc_stress_cmd_time_limit, psc_normal_cmd_time_limit,
1121 psc_lowat_check_queue_length, psc_hiwat_check_queue_length);
1122
1123 if (psc_lowat_check_queue_length == 0)
1124 msg_panic("compiler error: 0.7 * %d = %d", var_psc_pre_queue_limit,
1125 psc_lowat_check_queue_length);
1126 if (psc_hiwat_check_queue_length == 0)
1127 msg_panic("compiler error: 0.9 * %d = %d", var_psc_pre_queue_limit,
1128 psc_hiwat_check_queue_length);
1129
1130 /*
1131 * Per-client concurrency.
1132 */
1133 psc_client_concurrency = htable_create(var_psc_pre_queue_limit);
1134 }
1135
1136 MAIL_VERSION_STAMP_DECLARE;
1137
1138 /* main - pass control to the multi-threaded skeleton */
1139
main(int argc,char ** argv)1140 int main(int argc, char **argv)
1141 {
1142
1143 /*
1144 * List smtpd(8) parameters before any postscreen(8) parameters that have
1145 * defaults dependencies on them.
1146 */
1147 static const CONFIG_STR_TABLE str_table[] = {
1148 VAR_SMTPD_SERVICE, DEF_SMTPD_SERVICE, &var_smtpd_service, 1, 0,
1149 VAR_SMTPD_BANNER, DEF_SMTPD_BANNER, &var_smtpd_banner, 1, 0,
1150 VAR_SMTPD_FORBID_CMDS, DEF_SMTPD_FORBID_CMDS, &var_smtpd_forbid_cmds, 0, 0,
1151 VAR_SMTPD_EHLO_DIS_WORDS, DEF_SMTPD_EHLO_DIS_WORDS, &var_smtpd_ehlo_dis_words, 0, 0,
1152 VAR_SMTPD_EHLO_DIS_MAPS, DEF_SMTPD_EHLO_DIS_MAPS, &var_smtpd_ehlo_dis_maps, 0, 0,
1153 VAR_SMTPD_TLS_LEVEL, DEF_SMTPD_TLS_LEVEL, &var_smtpd_tls_level, 0, 0,
1154 VAR_SMTPD_CMD_FILTER, DEF_SMTPD_CMD_FILTER, &var_smtpd_cmd_filter, 0, 0,
1155 VAR_PSC_CACHE_MAP, DEF_PSC_CACHE_MAP, &var_psc_cache_map, 0, 0,
1156 VAR_PSC_PREGR_BANNER, DEF_PSC_PREGR_BANNER, &var_psc_pregr_banner, 0, 0,
1157 VAR_PSC_PREGR_ACTION, DEF_PSC_PREGR_ACTION, &var_psc_pregr_action, 1, 0,
1158 VAR_PSC_DNSBL_SITES, DEF_PSC_DNSBL_SITES, &var_psc_dnsbl_sites, 0, 0,
1159 VAR_PSC_DNSBL_ACTION, DEF_PSC_DNSBL_ACTION, &var_psc_dnsbl_action, 1, 0,
1160 VAR_PSC_PIPEL_ACTION, DEF_PSC_PIPEL_ACTION, &var_psc_pipel_action, 1, 0,
1161 VAR_PSC_NSMTP_ACTION, DEF_PSC_NSMTP_ACTION, &var_psc_nsmtp_action, 1, 0,
1162 VAR_PSC_BARLF_ACTION, DEF_PSC_BARLF_ACTION, &var_psc_barlf_action, 1, 0,
1163 VAR_PSC_ACL, DEF_PSC_ACL, &var_psc_acl, 0, 0,
1164 VAR_PSC_DNLIST_ACTION, DEF_PSC_DNLIST_ACTION, &var_psc_dnlist_action, 1, 0,
1165 VAR_PSC_FORBID_CMDS, DEF_PSC_FORBID_CMDS, &var_psc_forbid_cmds, 0, 0,
1166 VAR_PSC_EHLO_DIS_WORDS, DEF_PSC_EHLO_DIS_WORDS, &var_psc_ehlo_dis_words, 0, 0,
1167 VAR_PSC_EHLO_DIS_MAPS, DEF_PSC_EHLO_DIS_MAPS, &var_psc_ehlo_dis_maps, 0, 0,
1168 VAR_PSC_DNSBL_REPLY, DEF_PSC_DNSBL_REPLY, &var_psc_dnsbl_reply, 0, 0,
1169 VAR_PSC_TLS_LEVEL, DEF_PSC_TLS_LEVEL, &var_psc_tls_level, 0, 0,
1170 VAR_PSC_CMD_FILTER, DEF_PSC_CMD_FILTER, &var_psc_cmd_filter, 0, 0,
1171 VAR_DNSBLOG_SERVICE, DEF_DNSBLOG_SERVICE, &var_dnsblog_service, 1, 0,
1172 VAR_TLSPROXY_SERVICE, DEF_TLSPROXY_SERVICE, &var_tlsproxy_service, 1, 0,
1173 VAR_PSC_ALLIST_IF, DEF_PSC_ALLIST_IF, &var_psc_allist_if, 0, 0,
1174 VAR_PSC_UPROXY_PROTO, DEF_PSC_UPROXY_PROTO, &var_psc_uproxy_proto, 0, 0,
1175 VAR_PSC_REJ_FTR_MAPS, DEF_PSC_REJ_FTR_MAPS, &var_psc_rej_ftr_maps, 0, 0,
1176 0,
1177 };
1178 static const CONFIG_INT_TABLE int_table[] = {
1179 VAR_PSC_DNSBL_THRESH, DEF_PSC_DNSBL_THRESH, &var_psc_dnsbl_thresh, 0, 0,
1180 VAR_PSC_CMD_COUNT, DEF_PSC_CMD_COUNT, &var_psc_cmd_count, 1, 0,
1181 VAR_SMTPD_CCONN_LIMIT, DEF_SMTPD_CCONN_LIMIT, &var_smtpd_cconn_limit, 0, 0,
1182 0,
1183 };
1184 static const CONFIG_NINT_TABLE nint_table[] = {
1185 VAR_PSC_POST_QLIMIT, DEF_PSC_POST_QLIMIT, &var_psc_post_queue_limit, 5, 0,
1186 VAR_PSC_PRE_QLIMIT, DEF_PSC_PRE_QLIMIT, &var_psc_pre_queue_limit, 10, 0,
1187 VAR_PSC_CCONN_LIMIT, DEF_PSC_CCONN_LIMIT, &var_psc_cconn_limit, 0, 0,
1188 VAR_PSC_DNSBL_ALTHRESH, DEF_PSC_DNSBL_ALTHRESH, &var_psc_dnsbl_althresh, 0, 0,
1189 0,
1190 };
1191 static const CONFIG_TIME_TABLE time_table[] = {
1192 VAR_PSC_CMD_TIME, DEF_PSC_CMD_TIME, &var_psc_cmd_time, 1, 0,
1193 VAR_PSC_GREET_WAIT, DEF_PSC_GREET_WAIT, &var_psc_greet_wait, 1, 0,
1194 VAR_PSC_PREGR_TTL, DEF_PSC_PREGR_TTL, &var_psc_pregr_ttl, 1, 0,
1195 VAR_PSC_DNSBL_MIN_TTL, DEF_PSC_DNSBL_MIN_TTL, &var_psc_dnsbl_min_ttl, 1, 0,
1196 VAR_PSC_DNSBL_MAX_TTL, DEF_PSC_DNSBL_MAX_TTL, &var_psc_dnsbl_max_ttl, 1, 0,
1197 VAR_PSC_PIPEL_TTL, DEF_PSC_PIPEL_TTL, &var_psc_pipel_ttl, 1, 0,
1198 VAR_PSC_NSMTP_TTL, DEF_PSC_NSMTP_TTL, &var_psc_nsmtp_ttl, 1, 0,
1199 VAR_PSC_BARLF_TTL, DEF_PSC_BARLF_TTL, &var_psc_barlf_ttl, 1, 0,
1200 VAR_PSC_CACHE_RET, DEF_PSC_CACHE_RET, &var_psc_cache_ret, 1, 0,
1201 VAR_PSC_CACHE_SCAN, DEF_PSC_CACHE_SCAN, &var_psc_cache_scan, 0, 0,
1202 VAR_PSC_WATCHDOG, DEF_PSC_WATCHDOG, &var_psc_watchdog, 10, 0,
1203 VAR_PSC_UPROXY_TMOUT, DEF_PSC_UPROXY_TMOUT, &var_psc_uproxy_tmout, 1, 0,
1204 VAR_PSC_DNSBL_TMOUT, DEF_PSC_DNSBL_TMOUT, &var_psc_dnsbl_tmout, 1, 0,
1205
1206 0,
1207 };
1208 static const CONFIG_BOOL_TABLE bool_table[] = {
1209 VAR_HELO_REQUIRED, DEF_HELO_REQUIRED, &var_helo_required,
1210 VAR_DISABLE_VRFY_CMD, DEF_DISABLE_VRFY_CMD, &var_disable_vrfy_cmd,
1211 VAR_SMTPD_USE_TLS, DEF_SMTPD_USE_TLS, &var_smtpd_use_tls,
1212 VAR_SMTPD_ENFORCE_TLS, DEF_SMTPD_ENFORCE_TLS, &var_smtpd_enforce_tls,
1213 VAR_PSC_PIPEL_ENABLE, DEF_PSC_PIPEL_ENABLE, &var_psc_pipel_enable,
1214 VAR_PSC_NSMTP_ENABLE, DEF_PSC_NSMTP_ENABLE, &var_psc_nsmtp_enable,
1215 VAR_PSC_BARLF_ENABLE, DEF_PSC_BARLF_ENABLE, &var_psc_barlf_enable,
1216 0,
1217 };
1218 static const CONFIG_RAW_TABLE raw_table[] = {
1219 VAR_SMTPD_REJ_FOOTER, DEF_SMTPD_REJ_FOOTER, &var_smtpd_rej_footer, 0, 0,
1220 VAR_PSC_REJ_FOOTER, DEF_PSC_REJ_FOOTER, &var_psc_rej_footer, 0, 0,
1221 VAR_SMTPD_EXP_FILTER, DEF_SMTPD_EXP_FILTER, &var_smtpd_exp_filter, 1, 0,
1222 VAR_PSC_EXP_FILTER, DEF_PSC_EXP_FILTER, &var_psc_exp_filter, 1, 0,
1223 0,
1224 };
1225 static const CONFIG_NBOOL_TABLE nbool_table[] = {
1226 VAR_PSC_HELO_REQUIRED, DEF_PSC_HELO_REQUIRED, &var_psc_helo_required,
1227 VAR_PSC_DISABLE_VRFY, DEF_PSC_DISABLE_VRFY, &var_psc_disable_vrfy,
1228 VAR_PSC_USE_TLS, DEF_PSC_USE_TLS, &var_psc_use_tls,
1229 VAR_PSC_ENFORCE_TLS, DEF_PSC_ENFORCE_TLS, &var_psc_enforce_tls,
1230 0,
1231 };
1232
1233 /*
1234 * Fingerprint executables and core dumps.
1235 */
1236 MAIL_VERSION_STAMP_ALLOCATE;
1237
1238 event_server_main(argc, argv, psc_service,
1239 CA_MAIL_SERVER_STR_TABLE(str_table),
1240 CA_MAIL_SERVER_INT_TABLE(int_table),
1241 CA_MAIL_SERVER_NINT_TABLE(nint_table),
1242 CA_MAIL_SERVER_TIME_TABLE(time_table),
1243 CA_MAIL_SERVER_BOOL_TABLE(bool_table),
1244 CA_MAIL_SERVER_RAW_TABLE(raw_table),
1245 CA_MAIL_SERVER_NBOOL_TABLE(nbool_table),
1246 CA_MAIL_SERVER_PRE_INIT(pre_jail_init),
1247 CA_MAIL_SERVER_POST_INIT(post_jail_init),
1248 CA_MAIL_SERVER_PRE_ACCEPT(pre_accept),
1249 CA_MAIL_SERVER_SOLITARY,
1250 CA_MAIL_SERVER_SLOW_EXIT(psc_drain),
1251 CA_MAIL_SERVER_EXIT(psc_dump),
1252 CA_MAIL_SERVER_WATCHDOG(&var_psc_watchdog),
1253 0);
1254 }
1255