smtp.c revision 1.10
1/* $NetBSD: smtp.c,v 1.10 2017/02/14 01:16:48 christos Exp $ */ 2 3/*++ 4/* NAME 5/* smtp 8 6/* SUMMARY 7/* Postfix SMTP+LMTP client 8/* SYNOPSIS 9/* \fBsmtp\fR [generic Postfix daemon options] 10/* DESCRIPTION 11/* The Postfix SMTP+LMTP client implements the SMTP and LMTP mail 12/* delivery protocols. It processes message delivery requests from 13/* the queue manager. Each request specifies a queue file, a sender 14/* address, a domain or host to deliver to, and recipient information. 15/* This program expects to be run from the \fBmaster\fR(8) process 16/* manager. 17/* 18/* The SMTP+LMTP client updates the queue file and marks recipients 19/* as finished, or it informs the queue manager that delivery should 20/* be tried again at a later time. Delivery status reports are sent 21/* to the \fBbounce\fR(8), \fBdefer\fR(8) or \fBtrace\fR(8) daemon as 22/* appropriate. 23/* 24/* The SMTP+LMTP client looks up a list of mail exchanger addresses for 25/* the destination host, sorts the list by preference, and connects 26/* to each listed address until it finds a server that responds. 27/* 28/* When a server is not reachable, or when mail delivery fails due 29/* to a recoverable error condition, the SMTP+LMTP client will try to 30/* deliver the mail to an alternate host. 31/* 32/* After a successful mail transaction, a connection may be saved 33/* to the \fBscache\fR(8) connection cache server, so that it 34/* may be used by any SMTP+LMTP client for a subsequent transaction. 35/* 36/* By default, connection caching is enabled temporarily for 37/* destinations that have a high volume of mail in the active 38/* queue. Connection caching can be enabled permanently for 39/* specific destinations. 40/* SMTP DESTINATION SYNTAX 41/* .ad 42/* .fi 43/* SMTP destinations have the following form: 44/* .IP \fIdomainname\fR 45/* .IP \fIdomainname\fR:\fIport\fR 46/* Look up the mail exchangers for the specified domain, and 47/* connect to the specified port (default: \fBsmtp\fR). 48/* .IP [\fIhostname\fR] 49/* .IP [\fIhostname\fR]:\fIport\fR 50/* Look up the address(es) of the specified host, and connect to 51/* the specified port (default: \fBsmtp\fR). 52/* .IP [\fIaddress\fR] 53/* .IP [\fIaddress\fR]:\fIport\fR 54/* Connect to the host at the specified address, and connect 55/* to the specified port (default: \fBsmtp\fR). An IPv6 address 56/* must be formatted as [\fBipv6\fR:\fIaddress\fR]. 57/* LMTP DESTINATION SYNTAX 58/* .ad 59/* .fi 60/* LMTP destinations have the following form: 61/* .IP \fBunix\fR:\fIpathname\fR 62/* Connect to the local UNIX-domain server that is bound to the specified 63/* \fIpathname\fR. If the process runs chrooted, an absolute pathname 64/* is interpreted relative to the Postfix queue directory. 65/* .IP \fBinet\fR:\fIhostname\fR 66/* .IP \fBinet\fR:\fIhostname\fR:\fIport\fR 67/* .IP \fBinet\fR:[\fIaddress\fR] 68/* .IP \fBinet\fR:[\fIaddress\fR]:\fIport\fR 69/* Connect to the specified TCP port on the specified local or 70/* remote host. If no port is specified, connect to the port defined as 71/* \fBlmtp\fR in \fBservices\fR(4). 72/* If no such service is found, the \fBlmtp_tcp_port\fR configuration 73/* parameter (default value of 24) will be used. 74/* An IPv6 address must be formatted as [\fBipv6\fR:\fIaddress\fR]. 75/* .PP 76/* SECURITY 77/* .ad 78/* .fi 79/* The SMTP+LMTP client is moderately security-sensitive. It 80/* talks to SMTP or LMTP servers and to DNS servers on the 81/* network. The SMTP+LMTP client can be run chrooted at fixed 82/* low privilege. 83/* STANDARDS 84/* RFC 821 (SMTP protocol) 85/* RFC 822 (ARPA Internet Text Messages) 86/* RFC 1651 (SMTP service extensions) 87/* RFC 1652 (8bit-MIME transport) 88/* RFC 1870 (Message Size Declaration) 89/* RFC 2033 (LMTP protocol) 90/* RFC 2034 (SMTP Enhanced Error Codes) 91/* RFC 2045 (MIME: Format of Internet Message Bodies) 92/* RFC 2046 (MIME: Media Types) 93/* RFC 2554 (AUTH command) 94/* RFC 2821 (SMTP protocol) 95/* RFC 2920 (SMTP Pipelining) 96/* RFC 3207 (STARTTLS command) 97/* RFC 3461 (SMTP DSN Extension) 98/* RFC 3463 (Enhanced Status Codes) 99/* RFC 4954 (AUTH command) 100/* RFC 5321 (SMTP protocol) 101/* RFC 6531 (Internationalized SMTP) 102/* RFC 6533 (Internationalized Delivery Status Notifications) 103/* RFC 7672 (SMTP security via opportunistic DANE TLS) 104/* DIAGNOSTICS 105/* Problems and transactions are logged to \fBsyslogd\fR(8). 106/* Corrupted message files are marked so that the queue manager can 107/* move them to the \fBcorrupt\fR queue for further inspection. 108/* 109/* Depending on the setting of the \fBnotify_classes\fR parameter, 110/* the postmaster is notified of bounces, protocol problems, and of 111/* other trouble. 112/* BUGS 113/* SMTP and LMTP connection caching does not work with TLS. The necessary 114/* support for TLS object passivation and re-activation does not 115/* exist without closing the session, which defeats the purpose. 116/* 117/* SMTP and LMTP connection caching assumes that SASL credentials 118/* are valid for all destinations that map onto the same IP 119/* address and TCP port. 120/* CONFIGURATION PARAMETERS 121/* .ad 122/* .fi 123/* Before Postfix version 2.3, the LMTP client is a separate 124/* program that implements only a subset of the functionality 125/* available with SMTP: there is no support for TLS, and 126/* connections are cached in-process, making it ineffective 127/* when the client is used for multiple domains. 128/* 129/* Most smtp_\fIxxx\fR configuration parameters have an 130/* lmtp_\fIxxx\fR "mirror" parameter for the equivalent LMTP 131/* feature. This document describes only those LMTP-related 132/* parameters that aren't simply "mirror" parameters. 133/* 134/* Changes to \fBmain.cf\fR are picked up automatically, as \fBsmtp\fR(8) 135/* processes run for only a limited amount of time. Use the command 136/* "\fBpostfix reload\fR" to speed up a change. 137/* 138/* The text below provides only a parameter summary. See 139/* \fBpostconf\fR(5) for more details including examples. 140/* COMPATIBILITY CONTROLS 141/* .ad 142/* .fi 143/* .IP "\fBignore_mx_lookup_error (no)\fR" 144/* Ignore DNS MX lookups that produce no response. 145/* .IP "\fBsmtp_always_send_ehlo (yes)\fR" 146/* Always send EHLO at the start of an SMTP session. 147/* .IP "\fBsmtp_never_send_ehlo (no)\fR" 148/* Never send EHLO at the start of an SMTP session. 149/* .IP "\fBsmtp_defer_if_no_mx_address_found (no)\fR" 150/* Defer mail delivery when no MX record resolves to an IP address. 151/* .IP "\fBsmtp_line_length_limit (998)\fR" 152/* The maximal length of message header and body lines that Postfix 153/* will send via SMTP. 154/* .IP "\fBsmtp_pix_workaround_delay_time (10s)\fR" 155/* How long the Postfix SMTP client pauses before sending 156/* ".<CR><LF>" in order to work around the PIX firewall 157/* "<CR><LF>.<CR><LF>" bug. 158/* .IP "\fBsmtp_pix_workaround_threshold_time (500s)\fR" 159/* How long a message must be queued before the Postfix SMTP client 160/* turns on the PIX firewall "<CR><LF>.<CR><LF>" 161/* bug workaround for delivery through firewalls with "smtp fixup" 162/* mode turned on. 163/* .IP "\fBsmtp_pix_workarounds (disable_esmtp, delay_dotcrlf)\fR" 164/* A list that specifies zero or more workarounds for CISCO PIX 165/* firewall bugs. 166/* .IP "\fBsmtp_pix_workaround_maps (empty)\fR" 167/* Lookup tables, indexed by the remote SMTP server address, with 168/* per-destination workarounds for CISCO PIX firewall bugs. 169/* .IP "\fBsmtp_quote_rfc821_envelope (yes)\fR" 170/* Quote addresses in Postfix SMTP client MAIL FROM and RCPT TO commands 171/* as required 172/* by RFC 5321. 173/* .IP "\fBsmtp_reply_filter (empty)\fR" 174/* A mechanism to transform replies from remote SMTP servers one 175/* line at a time. 176/* .IP "\fBsmtp_skip_5xx_greeting (yes)\fR" 177/* Skip remote SMTP servers that greet with a 5XX status code. 178/* .IP "\fBsmtp_skip_quit_response (yes)\fR" 179/* Do not wait for the response to the SMTP QUIT command. 180/* .PP 181/* Available in Postfix version 2.0 and earlier: 182/* .IP "\fBsmtp_skip_4xx_greeting (yes)\fR" 183/* Skip SMTP servers that greet with a 4XX status code (go away, try 184/* again later). 185/* .PP 186/* Available in Postfix version 2.2 and later: 187/* .IP "\fBsmtp_discard_ehlo_keyword_address_maps (empty)\fR" 188/* Lookup tables, indexed by the remote SMTP server address, with 189/* case insensitive lists of EHLO keywords (pipelining, starttls, auth, 190/* etc.) that the Postfix SMTP client will ignore in the EHLO response from a 191/* remote SMTP server. 192/* .IP "\fBsmtp_discard_ehlo_keywords (empty)\fR" 193/* A case insensitive list of EHLO keywords (pipelining, starttls, 194/* auth, etc.) that the Postfix SMTP client will ignore in the EHLO 195/* response from a remote SMTP server. 196/* .IP "\fBsmtp_generic_maps (empty)\fR" 197/* Optional lookup tables that perform address rewriting in the 198/* Postfix SMTP client, typically to transform a locally valid address into 199/* a globally valid address when sending mail across the Internet. 200/* .PP 201/* Available in Postfix version 2.2.9 and later: 202/* .IP "\fBsmtp_cname_overrides_servername (version dependent)\fR" 203/* When the remote SMTP servername is a DNS CNAME, replace the 204/* servername with the result from CNAME expansion for the purpose of 205/* logging, SASL password lookup, TLS 206/* policy decisions, or TLS certificate verification. 207/* .PP 208/* Available in Postfix version 2.3 and later: 209/* .IP "\fBlmtp_discard_lhlo_keyword_address_maps (empty)\fR" 210/* Lookup tables, indexed by the remote LMTP server address, with 211/* case insensitive lists of LHLO keywords (pipelining, starttls, 212/* auth, etc.) that the Postfix LMTP client will ignore in the LHLO 213/* response 214/* from a remote LMTP server. 215/* .IP "\fBlmtp_discard_lhlo_keywords (empty)\fR" 216/* A case insensitive list of LHLO keywords (pipelining, starttls, 217/* auth, etc.) that the Postfix LMTP client will ignore in the LHLO 218/* response 219/* from a remote LMTP server. 220/* .PP 221/* Available in Postfix version 2.4.4 and later: 222/* .IP "\fBsend_cyrus_sasl_authzid (no)\fR" 223/* When authenticating to a remote SMTP or LMTP server with the 224/* default setting "no", send no SASL authoriZation ID (authzid); send 225/* only the SASL authentiCation ID (authcid) plus the authcid's password. 226/* .PP 227/* Available in Postfix version 2.5 and later: 228/* .IP "\fBsmtp_header_checks (empty)\fR" 229/* Restricted \fBheader_checks\fR(5) tables for the Postfix SMTP client. 230/* .IP "\fBsmtp_mime_header_checks (empty)\fR" 231/* Restricted \fBmime_header_checks\fR(5) tables for the Postfix SMTP 232/* client. 233/* .IP "\fBsmtp_nested_header_checks (empty)\fR" 234/* Restricted \fBnested_header_checks\fR(5) tables for the Postfix SMTP 235/* client. 236/* .IP "\fBsmtp_body_checks (empty)\fR" 237/* Restricted \fBbody_checks\fR(5) tables for the Postfix SMTP client. 238/* .PP 239/* Available in Postfix version 2.6 and later: 240/* .IP "\fBtcp_windowsize (0)\fR" 241/* An optional workaround for routers that break TCP window scaling. 242/* .PP 243/* Available in Postfix version 2.8 and later: 244/* .IP "\fBsmtp_dns_resolver_options (empty)\fR" 245/* DNS Resolver options for the Postfix SMTP client. 246/* .PP 247/* Available in Postfix version 2.9 and later: 248/* .IP "\fBsmtp_per_record_deadline (no)\fR" 249/* Change the behavior of the smtp_*_timeout time limits, from a 250/* time limit per read or write system call, to a time limit to send 251/* or receive a complete record (an SMTP command line, SMTP response 252/* line, SMTP message content line, or TLS protocol message). 253/* .IP "\fBsmtp_send_dummy_mail_auth (no)\fR" 254/* Whether or not to append the "AUTH=<>" option to the MAIL 255/* FROM command in SASL-authenticated SMTP sessions. 256/* .PP 257/* Available in Postfix version 2.11 and later: 258/* .IP "\fBsmtp_dns_support_level (empty)\fR" 259/* Level of DNS support in the Postfix SMTP client. 260/* .PP 261/* Available in Postfix version 3.0 and later: 262/* .IP "\fBsmtp_delivery_status_filter ($default_delivery_status_filter)\fR" 263/* Optional filter for the \fBsmtp\fR(8) delivery agent to change the 264/* delivery status code or explanatory text of successful or unsuccessful 265/* deliveries. 266/* .IP "\fBsmtp_dns_reply_filter (empty)\fR" 267/* Optional filter for Postfix SMTP client DNS lookup results. 268/* MIME PROCESSING CONTROLS 269/* .ad 270/* .fi 271/* Available in Postfix version 2.0 and later: 272/* .IP "\fBdisable_mime_output_conversion (no)\fR" 273/* Disable the conversion of 8BITMIME format to 7BIT format. 274/* .IP "\fBmime_boundary_length_limit (2048)\fR" 275/* The maximal length of MIME multipart boundary strings. 276/* .IP "\fBmime_nesting_limit (100)\fR" 277/* The maximal recursion level that the MIME processor will handle. 278/* EXTERNAL CONTENT INSPECTION CONTROLS 279/* .ad 280/* .fi 281/* Available in Postfix version 2.1 and later: 282/* .IP "\fBsmtp_send_xforward_command (no)\fR" 283/* Send the non-standard XFORWARD command when the Postfix SMTP server 284/* EHLO response announces XFORWARD support. 285/* SASL AUTHENTICATION CONTROLS 286/* .ad 287/* .fi 288/* .IP "\fBsmtp_sasl_auth_enable (no)\fR" 289/* Enable SASL authentication in the Postfix SMTP client. 290/* .IP "\fBsmtp_sasl_password_maps (empty)\fR" 291/* Optional Postfix SMTP client lookup tables with one username:password 292/* entry per sender, remote hostname or next-hop domain. 293/* .IP "\fBsmtp_sasl_security_options (noplaintext, noanonymous)\fR" 294/* Postfix SMTP client SASL security options; as of Postfix 2.3 295/* the list of available 296/* features depends on the SASL client implementation that is selected 297/* with \fBsmtp_sasl_type\fR. 298/* .PP 299/* Available in Postfix version 2.2 and later: 300/* .IP "\fBsmtp_sasl_mechanism_filter (empty)\fR" 301/* If non-empty, a Postfix SMTP client filter for the remote SMTP 302/* server's list of offered SASL mechanisms. 303/* .PP 304/* Available in Postfix version 2.3 and later: 305/* .IP "\fBsmtp_sender_dependent_authentication (no)\fR" 306/* Enable sender-dependent authentication in the Postfix SMTP client; this is 307/* available only with SASL authentication, and disables SMTP connection 308/* caching to ensure that mail from different senders will use the 309/* appropriate credentials. 310/* .IP "\fBsmtp_sasl_path (empty)\fR" 311/* Implementation-specific information that the Postfix SMTP client 312/* passes through to 313/* the SASL plug-in implementation that is selected with 314/* \fBsmtp_sasl_type\fR. 315/* .IP "\fBsmtp_sasl_type (cyrus)\fR" 316/* The SASL plug-in type that the Postfix SMTP client should use 317/* for authentication. 318/* .PP 319/* Available in Postfix version 2.5 and later: 320/* .IP "\fBsmtp_sasl_auth_cache_name (empty)\fR" 321/* An optional table to prevent repeated SASL authentication 322/* failures with the same remote SMTP server hostname, username and 323/* password. 324/* .IP "\fBsmtp_sasl_auth_cache_time (90d)\fR" 325/* The maximal age of an smtp_sasl_auth_cache_name entry before it 326/* is removed. 327/* .IP "\fBsmtp_sasl_auth_soft_bounce (yes)\fR" 328/* When a remote SMTP server rejects a SASL authentication request 329/* with a 535 reply code, defer mail delivery instead of returning 330/* mail as undeliverable. 331/* .PP 332/* Available in Postfix version 2.9 and later: 333/* .IP "\fBsmtp_send_dummy_mail_auth (no)\fR" 334/* Whether or not to append the "AUTH=<>" option to the MAIL 335/* FROM command in SASL-authenticated SMTP sessions. 336/* STARTTLS SUPPORT CONTROLS 337/* .ad 338/* .fi 339/* Detailed information about STARTTLS configuration may be found 340/* in the TLS_README document. 341/* .IP "\fBsmtp_tls_security_level (empty)\fR" 342/* The default SMTP TLS security level for the Postfix SMTP client; 343/* when a non-empty value is specified, this overrides the obsolete 344/* parameters smtp_use_tls, smtp_enforce_tls, and smtp_tls_enforce_peername. 345/* .IP "\fBsmtp_sasl_tls_security_options ($smtp_sasl_security_options)\fR" 346/* The SASL authentication security options that the Postfix SMTP 347/* client uses for TLS encrypted SMTP sessions. 348/* .IP "\fBsmtp_starttls_timeout (300s)\fR" 349/* Time limit for Postfix SMTP client write and read operations 350/* during TLS startup and shutdown handshake procedures. 351/* .IP "\fBsmtp_tls_CAfile (empty)\fR" 352/* A file containing CA certificates of root CAs trusted to sign 353/* either remote SMTP server certificates or intermediate CA certificates. 354/* .IP "\fBsmtp_tls_CApath (empty)\fR" 355/* Directory with PEM format Certification Authority certificates 356/* that the Postfix SMTP client uses to verify a remote SMTP server 357/* certificate. 358/* .IP "\fBsmtp_tls_cert_file (empty)\fR" 359/* File with the Postfix SMTP client RSA certificate in PEM format. 360/* .IP "\fBsmtp_tls_mandatory_ciphers (medium)\fR" 361/* The minimum TLS cipher grade that the Postfix SMTP client will 362/* use with 363/* mandatory TLS encryption. 364/* .IP "\fBsmtp_tls_exclude_ciphers (empty)\fR" 365/* List of ciphers or cipher types to exclude from the Postfix 366/* SMTP client cipher 367/* list at all TLS security levels. 368/* .IP "\fBsmtp_tls_mandatory_exclude_ciphers (empty)\fR" 369/* Additional list of ciphers or cipher types to exclude from the 370/* Postfix SMTP client cipher list at mandatory TLS security levels. 371/* .IP "\fBsmtp_tls_dcert_file (empty)\fR" 372/* File with the Postfix SMTP client DSA certificate in PEM format. 373/* .IP "\fBsmtp_tls_dkey_file ($smtp_tls_dcert_file)\fR" 374/* File with the Postfix SMTP client DSA private key in PEM format. 375/* .IP "\fBsmtp_tls_key_file ($smtp_tls_cert_file)\fR" 376/* File with the Postfix SMTP client RSA private key in PEM format. 377/* .IP "\fBsmtp_tls_loglevel (0)\fR" 378/* Enable additional Postfix SMTP client logging of TLS activity. 379/* .IP "\fBsmtp_tls_note_starttls_offer (no)\fR" 380/* Log the hostname of a remote SMTP server that offers STARTTLS, 381/* when TLS is not already enabled for that server. 382/* .IP "\fBsmtp_tls_policy_maps (empty)\fR" 383/* Optional lookup tables with the Postfix SMTP client TLS security 384/* policy by next-hop destination; when a non-empty value is specified, 385/* this overrides the obsolete smtp_tls_per_site parameter. 386/* .IP "\fBsmtp_tls_mandatory_protocols (!SSLv2, !SSLv3)\fR" 387/* List of SSL/TLS protocols that the Postfix SMTP client will use with 388/* mandatory TLS encryption. 389/* .IP "\fBsmtp_tls_scert_verifydepth (9)\fR" 390/* The verification depth for remote SMTP server certificates. 391/* .IP "\fBsmtp_tls_secure_cert_match (nexthop, dot-nexthop)\fR" 392/* How the Postfix SMTP client verifies the server certificate 393/* peername for the "secure" TLS security level. 394/* .IP "\fBsmtp_tls_session_cache_database (empty)\fR" 395/* Name of the file containing the optional Postfix SMTP client 396/* TLS session cache. 397/* .IP "\fBsmtp_tls_session_cache_timeout (3600s)\fR" 398/* The expiration time of Postfix SMTP client TLS session cache 399/* information. 400/* .IP "\fBsmtp_tls_verify_cert_match (hostname)\fR" 401/* How the Postfix SMTP client verifies the server certificate 402/* peername for the 403/* "verify" TLS security level. 404/* .IP "\fBtls_daemon_random_bytes (32)\fR" 405/* The number of pseudo-random bytes that an \fBsmtp\fR(8) or \fBsmtpd\fR(8) 406/* process requests from the \fBtlsmgr\fR(8) server in order to seed its 407/* internal pseudo random number generator (PRNG). 408/* .IP "\fBtls_high_cipherlist (see 'postconf -d' output)\fR" 409/* The OpenSSL cipherlist for "high" grade ciphers. 410/* .IP "\fBtls_medium_cipherlist (see 'postconf -d' output)\fR" 411/* The OpenSSL cipherlist for "medium" or higher grade ciphers. 412/* .IP "\fBtls_low_cipherlist (see 'postconf -d' output)\fR" 413/* The OpenSSL cipherlist for "low" or higher grade ciphers. 414/* .IP "\fBtls_export_cipherlist (see 'postconf -d' output)\fR" 415/* The OpenSSL cipherlist for "export" or higher grade ciphers. 416/* .IP "\fBtls_null_cipherlist (eNULL:!aNULL)\fR" 417/* The OpenSSL cipherlist for "NULL" grade ciphers that provide 418/* authentication without encryption. 419/* .PP 420/* Available in Postfix version 2.4 and later: 421/* .IP "\fBsmtp_sasl_tls_verified_security_options ($smtp_sasl_tls_security_options)\fR" 422/* The SASL authentication security options that the Postfix SMTP 423/* client uses for TLS encrypted SMTP sessions with a verified server 424/* certificate. 425/* .PP 426/* Available in Postfix version 2.5 and later: 427/* .IP "\fBsmtp_tls_fingerprint_cert_match (empty)\fR" 428/* List of acceptable remote SMTP server certificate fingerprints for 429/* the "fingerprint" TLS security level (\fBsmtp_tls_security_level\fR = 430/* fingerprint). 431/* .IP "\fBsmtp_tls_fingerprint_digest (md5)\fR" 432/* The message digest algorithm used to construct remote SMTP server 433/* certificate fingerprints. 434/* .PP 435/* Available in Postfix version 2.6 and later: 436/* .IP "\fBsmtp_tls_protocols (!SSLv2, !SSLv3)\fR" 437/* List of TLS protocols that the Postfix SMTP client will exclude or 438/* include with opportunistic TLS encryption. 439/* .IP "\fBsmtp_tls_ciphers (medium)\fR" 440/* The minimum TLS cipher grade that the Postfix SMTP client 441/* will use with opportunistic TLS encryption. 442/* .IP "\fBsmtp_tls_eccert_file (empty)\fR" 443/* File with the Postfix SMTP client ECDSA certificate in PEM format. 444/* .IP "\fBsmtp_tls_eckey_file ($smtp_tls_eccert_file)\fR" 445/* File with the Postfix SMTP client ECDSA private key in PEM format. 446/* .PP 447/* Available in Postfix version 2.7 and later: 448/* .IP "\fBsmtp_tls_block_early_mail_reply (no)\fR" 449/* Try to detect a mail hijacking attack based on a TLS protocol 450/* vulnerability (CVE-2009-3555), where an attacker prepends malicious 451/* HELO, MAIL, RCPT, DATA commands to a Postfix SMTP client TLS session. 452/* .PP 453/* Available in Postfix version 2.8 and later: 454/* .IP "\fBtls_disable_workarounds (see 'postconf -d' output)\fR" 455/* List or bit-mask of OpenSSL bug work-arounds to disable. 456/* .PP 457/* Available in Postfix version 2.11 and later: 458/* .IP "\fBsmtp_tls_trust_anchor_file (empty)\fR" 459/* Zero or more PEM-format files with trust-anchor certificates 460/* and/or public keys. 461/* .IP "\fBsmtp_tls_force_insecure_host_tlsa_lookup (no)\fR" 462/* Lookup the associated DANE TLSA RRset even when a hostname is 463/* not an alias and its address records lie in an unsigned zone. 464/* .IP "\fBtls_dane_trust_anchor_digest_enable (yes)\fR" 465/* RFC 6698 trust-anchor digest support in the Postfix TLS library. 466/* .IP "\fBtlsmgr_service_name (tlsmgr)\fR" 467/* The name of the \fBtlsmgr\fR(8) service entry in master.cf. 468/* .PP 469/* Available in Postfix version 3.0 and later: 470/* .IP "\fBsmtp_tls_wrappermode (no)\fR" 471/* Request that the Postfix SMTP client connects using the 472/* legacy SMTPS protocol instead of using the STARTTLS command. 473/* .PP 474/* Available in Postfix version 3.1 and later: 475/* .IP "\fBsmtp_tls_dane_insecure_mx_policy (dane)\fR" 476/* The TLS policy for MX hosts with "secure" TLSA records when the 477/* nexthop destination security level is \fBdane\fR, but the MX 478/* record was found via an "insecure" MX lookup. 479/* OBSOLETE STARTTLS CONTROLS 480/* .ad 481/* .fi 482/* The following configuration parameters exist for compatibility 483/* with Postfix versions before 2.3. Support for these will 484/* be removed in a future release. 485/* .IP "\fBsmtp_use_tls (no)\fR" 486/* Opportunistic mode: use TLS when a remote SMTP server announces 487/* STARTTLS support, otherwise send the mail in the clear. 488/* .IP "\fBsmtp_enforce_tls (no)\fR" 489/* Enforcement mode: require that remote SMTP servers use TLS 490/* encryption, and never send mail in the clear. 491/* .IP "\fBsmtp_tls_enforce_peername (yes)\fR" 492/* With mandatory TLS encryption, require that the remote SMTP 493/* server hostname matches the information in the remote SMTP server 494/* certificate. 495/* .IP "\fBsmtp_tls_per_site (empty)\fR" 496/* Optional lookup tables with the Postfix SMTP client TLS usage 497/* policy by next-hop destination and by remote SMTP server hostname. 498/* .IP "\fBsmtp_tls_cipherlist (empty)\fR" 499/* Obsolete Postfix < 2.3 control for the Postfix SMTP client TLS 500/* cipher list. 501/* RESOURCE AND RATE CONTROLS 502/* .ad 503/* .fi 504/* .IP "\fBsmtp_destination_concurrency_limit ($default_destination_concurrency_limit)\fR" 505/* The maximal number of parallel deliveries to the same destination 506/* via the smtp message delivery transport. 507/* .IP "\fBsmtp_destination_recipient_limit ($default_destination_recipient_limit)\fR" 508/* The maximal number of recipients per message for the smtp 509/* message delivery transport. 510/* .IP "\fBsmtp_connect_timeout (30s)\fR" 511/* The Postfix SMTP client time limit for completing a TCP connection, or 512/* zero (use the operating system built-in time limit). 513/* .IP "\fBsmtp_helo_timeout (300s)\fR" 514/* The Postfix SMTP client time limit for sending the HELO or EHLO command, 515/* and for receiving the initial remote SMTP server response. 516/* .IP "\fBlmtp_lhlo_timeout (300s)\fR" 517/* The Postfix LMTP client time limit for sending the LHLO command, 518/* and for receiving the initial remote LMTP server response. 519/* .IP "\fBsmtp_xforward_timeout (300s)\fR" 520/* The Postfix SMTP client time limit for sending the XFORWARD command, 521/* and for receiving the remote SMTP server response. 522/* .IP "\fBsmtp_mail_timeout (300s)\fR" 523/* The Postfix SMTP client time limit for sending the MAIL FROM command, 524/* and for receiving the remote SMTP server response. 525/* .IP "\fBsmtp_rcpt_timeout (300s)\fR" 526/* The Postfix SMTP client time limit for sending the SMTP RCPT TO 527/* command, and for receiving the remote SMTP server response. 528/* .IP "\fBsmtp_data_init_timeout (120s)\fR" 529/* The Postfix SMTP client time limit for sending the SMTP DATA command, 530/* and for receiving the remote SMTP server response. 531/* .IP "\fBsmtp_data_xfer_timeout (180s)\fR" 532/* The Postfix SMTP client time limit for sending the SMTP message content. 533/* .IP "\fBsmtp_data_done_timeout (600s)\fR" 534/* The Postfix SMTP client time limit for sending the SMTP ".", and 535/* for receiving the remote SMTP server response. 536/* .IP "\fBsmtp_quit_timeout (300s)\fR" 537/* The Postfix SMTP client time limit for sending the QUIT command, 538/* and for receiving the remote SMTP server response. 539/* .PP 540/* Available in Postfix version 2.1 and later: 541/* .IP "\fBsmtp_mx_address_limit (5)\fR" 542/* The maximal number of MX (mail exchanger) IP addresses that can 543/* result from Postfix SMTP client mail exchanger lookups, or zero (no 544/* limit). 545/* .IP "\fBsmtp_mx_session_limit (2)\fR" 546/* The maximal number of SMTP sessions per delivery request before 547/* the Postfix SMTP client 548/* gives up or delivers to a fall-back relay host, or zero (no 549/* limit). 550/* .IP "\fBsmtp_rset_timeout (20s)\fR" 551/* The Postfix SMTP client time limit for sending the RSET command, 552/* and for receiving the remote SMTP server response. 553/* .PP 554/* Available in Postfix version 2.2 and earlier: 555/* .IP "\fBlmtp_cache_connection (yes)\fR" 556/* Keep Postfix LMTP client connections open for up to $max_idle 557/* seconds. 558/* .PP 559/* Available in Postfix version 2.2 and later: 560/* .IP "\fBsmtp_connection_cache_destinations (empty)\fR" 561/* Permanently enable SMTP connection caching for the specified 562/* destinations. 563/* .IP "\fBsmtp_connection_cache_on_demand (yes)\fR" 564/* Temporarily enable SMTP connection caching while a destination 565/* has a high volume of mail in the active queue. 566/* .IP "\fBsmtp_connection_reuse_time_limit (300s)\fR" 567/* The amount of time during which Postfix will use an SMTP 568/* connection repeatedly. 569/* .IP "\fBsmtp_connection_cache_time_limit (2s)\fR" 570/* When SMTP connection caching is enabled, the amount of time that 571/* an unused SMTP client socket is kept open before it is closed. 572/* .PP 573/* Available in Postfix version 2.3 and later: 574/* .IP "\fBconnection_cache_protocol_timeout (5s)\fR" 575/* Time limit for connection cache connect, send or receive 576/* operations. 577/* .PP 578/* Available in Postfix version 2.9 and later: 579/* .IP "\fBsmtp_per_record_deadline (no)\fR" 580/* Change the behavior of the smtp_*_timeout time limits, from a 581/* time limit per read or write system call, to a time limit to send 582/* or receive a complete record (an SMTP command line, SMTP response 583/* line, SMTP message content line, or TLS protocol message). 584/* .PP 585/* Available in Postfix version 2.11 and later: 586/* .IP "\fBsmtp_connection_reuse_count_limit (0)\fR" 587/* When SMTP connection caching is enabled, the number of times 588/* that an SMTP session may be reused before it is closed, or zero (no 589/* limit). 590/* SMTPUTF8 CONTROLS 591/* .ad 592/* .fi 593/* Preliminary SMTPUTF8 support is introduced with Postfix 3.0. 594/* .IP "\fBsmtputf8_enable (yes)\fR" 595/* Enable preliminary SMTPUTF8 support for the protocols described 596/* in RFC 6531..6533. 597/* .IP "\fBsmtputf8_autodetect_classes (sendmail, verify)\fR" 598/* Detect that a message requires SMTPUTF8 support for the specified 599/* mail origin classes. 600/* TROUBLE SHOOTING CONTROLS 601/* .ad 602/* .fi 603/* .IP "\fBdebug_peer_level (2)\fR" 604/* The increment in verbose logging level when a remote client or 605/* server matches a pattern in the debug_peer_list parameter. 606/* .IP "\fBdebug_peer_list (empty)\fR" 607/* Optional list of remote client or server hostname or network 608/* address patterns that cause the verbose logging level to increase 609/* by the amount specified in $debug_peer_level. 610/* .IP "\fBerror_notice_recipient (postmaster)\fR" 611/* The recipient of postmaster notifications about mail delivery 612/* problems that are caused by policy, resource, software or protocol 613/* errors. 614/* .IP "\fBinternal_mail_filter_classes (empty)\fR" 615/* What categories of Postfix-generated mail are subject to 616/* before-queue content inspection by non_smtpd_milters, header_checks 617/* and body_checks. 618/* .IP "\fBnotify_classes (resource, software)\fR" 619/* The list of error classes that are reported to the postmaster. 620/* MISCELLANEOUS CONTROLS 621/* .ad 622/* .fi 623/* .IP "\fBbest_mx_transport (empty)\fR" 624/* Where the Postfix SMTP client should deliver mail when it detects 625/* a "mail loops back to myself" error condition. 626/* .IP "\fBconfig_directory (see 'postconf -d' output)\fR" 627/* The default location of the Postfix main.cf and master.cf 628/* configuration files. 629/* .IP "\fBdaemon_timeout (18000s)\fR" 630/* How much time a Postfix daemon process may take to handle a 631/* request before it is terminated by a built-in watchdog timer. 632/* .IP "\fBdelay_logging_resolution_limit (2)\fR" 633/* The maximal number of digits after the decimal point when logging 634/* sub-second delay values. 635/* .IP "\fBdisable_dns_lookups (no)\fR" 636/* Disable DNS lookups in the Postfix SMTP and LMTP clients. 637/* .IP "\fBinet_interfaces (all)\fR" 638/* The network interface addresses that this mail system receives 639/* mail on. 640/* .IP "\fBinet_protocols (all)\fR" 641/* The Internet protocols Postfix will attempt to use when making 642/* or accepting connections. 643/* .IP "\fBipc_timeout (3600s)\fR" 644/* The time limit for sending or receiving information over an internal 645/* communication channel. 646/* .IP "\fBlmtp_assume_final (no)\fR" 647/* When a remote LMTP server announces no DSN support, assume that 648/* the 649/* server performs final delivery, and send "delivered" delivery status 650/* notifications instead of "relayed". 651/* .IP "\fBlmtp_tcp_port (24)\fR" 652/* The default TCP port that the Postfix LMTP client connects to. 653/* .IP "\fBmax_idle (100s)\fR" 654/* The maximum amount of time that an idle Postfix daemon process waits 655/* for an incoming connection before terminating voluntarily. 656/* .IP "\fBmax_use (100)\fR" 657/* The maximal number of incoming connections that a Postfix daemon 658/* process will service before terminating voluntarily. 659/* .IP "\fBprocess_id (read-only)\fR" 660/* The process ID of a Postfix command or daemon process. 661/* .IP "\fBprocess_name (read-only)\fR" 662/* The process name of a Postfix command or daemon process. 663/* .IP "\fBproxy_interfaces (empty)\fR" 664/* The network interface addresses that this mail system receives mail 665/* on by way of a proxy or network address translation unit. 666/* .IP "\fBsmtp_address_preference (any)\fR" 667/* The address type ("ipv6", "ipv4" or "any") that the Postfix 668/* SMTP client will try first, when a destination has IPv6 and IPv4 669/* addresses with equal MX preference. 670/* .IP "\fBsmtp_bind_address (empty)\fR" 671/* An optional numerical network address that the Postfix SMTP client 672/* should bind to when making an IPv4 connection. 673/* .IP "\fBsmtp_bind_address6 (empty)\fR" 674/* An optional numerical network address that the Postfix SMTP client 675/* should bind to when making an IPv6 connection. 676/* .IP "\fBsmtp_helo_name ($myhostname)\fR" 677/* The hostname to send in the SMTP HELO or EHLO command. 678/* .IP "\fBlmtp_lhlo_name ($myhostname)\fR" 679/* The hostname to send in the LMTP LHLO command. 680/* .IP "\fBsmtp_host_lookup (dns)\fR" 681/* What mechanisms the Postfix SMTP client uses to look up a host's 682/* IP address. 683/* .IP "\fBsmtp_randomize_addresses (yes)\fR" 684/* Randomize the order of equal-preference MX host addresses. 685/* .IP "\fBsyslog_facility (mail)\fR" 686/* The syslog facility of Postfix logging. 687/* .IP "\fBsyslog_name (see 'postconf -d' output)\fR" 688/* The mail system name that is prepended to the process name in syslog 689/* records, so that "smtpd" becomes, for example, "postfix/smtpd". 690/* .PP 691/* Available with Postfix 2.2 and earlier: 692/* .IP "\fBfallback_relay (empty)\fR" 693/* Optional list of relay hosts for SMTP destinations that can't be 694/* found or that are unreachable. 695/* .PP 696/* Available with Postfix 2.3 and later: 697/* .IP "\fBsmtp_fallback_relay ($fallback_relay)\fR" 698/* Optional list of relay hosts for SMTP destinations that can't be 699/* found or that are unreachable. 700/* .PP 701/* Available with Postfix 3.0 and later: 702/* .IP "\fBsmtp_address_verify_target (rcpt)\fR" 703/* In the context of email address verification, the SMTP protocol 704/* stage that determines whether an email address is deliverable. 705/* .PP 706/* Available with Postfix 3.1 and later: 707/* .IP "\fBlmtp_fallback_relay (empty)\fR" 708/* Optional list of relay hosts for LMTP destinations that can't be 709/* found or that are unreachable. 710/* SEE ALSO 711/* generic(5), output address rewriting 712/* header_checks(5), message header content inspection 713/* body_checks(5), body parts content inspection 714/* qmgr(8), queue manager 715/* bounce(8), delivery status reports 716/* scache(8), connection cache server 717/* postconf(5), configuration parameters 718/* master(5), generic daemon options 719/* master(8), process manager 720/* tlsmgr(8), TLS session and PRNG management 721/* syslogd(8), system logging 722/* README FILES 723/* .ad 724/* .fi 725/* Use "\fBpostconf readme_directory\fR" or 726/* "\fBpostconf html_directory\fR" to locate this information. 727/* .na 728/* .nf 729/* SASL_README, Postfix SASL howto 730/* TLS_README, Postfix STARTTLS howto 731/* LICENSE 732/* .ad 733/* .fi 734/* The Secure Mailer license must be distributed with this software. 735/* AUTHOR(S) 736/* Wietse Venema 737/* IBM T.J. Watson Research 738/* P.O. Box 704 739/* Yorktown Heights, NY 10598, USA 740/* 741/* Wietse Venema 742/* Google, Inc. 743/* 111 8th Avenue 744/* New York, NY 10011, USA 745/* 746/* Command pipelining in cooperation with: 747/* Jon Ribbens 748/* Oaktree Internet Solutions Ltd., 749/* Internet House, 750/* Canal Basin, 751/* Coventry, 752/* CV1 4LY, United Kingdom. 753/* 754/* SASL support originally by: 755/* Till Franke 756/* SuSE Rhein/Main AG 757/* 65760 Eschborn, Germany 758/* 759/* TLS support originally by: 760/* Lutz Jaenicke 761/* BTU Cottbus 762/* Allgemeine Elektrotechnik 763/* Universitaetsplatz 3-4 764/* D-03044 Cottbus, Germany 765/* 766/* Revised TLS and SMTP connection cache support by: 767/* Victor Duchovni 768/* Morgan Stanley 769/*--*/ 770 771/* System library. */ 772 773#include <sys_defs.h> 774#include <unistd.h> 775#include <stdlib.h> 776#include <string.h> 777#include <fcntl.h> 778#include <dict.h> 779#include <stringops.h> 780 781/* Utility library. */ 782 783#include <msg.h> 784#include <mymalloc.h> 785#include <name_mask.h> 786#include <name_code.h> 787 788/* Global library. */ 789 790#include <deliver_request.h> 791#include <mail_params.h> 792#include <mail_version.h> 793#include <mail_conf.h> 794#include <debug_peer.h> 795#include <flush_clnt.h> 796#include <scache.h> 797#include <string_list.h> 798#include <maps.h> 799#include <ext_prop.h> 800 801/* DNS library. */ 802 803#include <dns.h> 804 805/* Single server skeleton. */ 806 807#include <mail_server.h> 808 809/* Application-specific. */ 810 811#include "smtp.h" 812#include "smtp_sasl.h" 813 814 /* 815 * Tunable parameters. These have compiled-in defaults that can be overruled 816 * by settings in the global Postfix configuration file. 817 */ 818int var_smtp_conn_tmout; 819int var_smtp_helo_tmout; 820int var_smtp_xfwd_tmout; 821int var_smtp_mail_tmout; 822int var_smtp_rcpt_tmout; 823int var_smtp_data0_tmout; 824int var_smtp_data1_tmout; 825int var_smtp_data2_tmout; 826int var_smtp_rset_tmout; 827int var_smtp_quit_tmout; 828char *var_inet_interfaces; 829char *var_notify_classes; 830int var_smtp_skip_5xx_greeting; 831int var_ign_mx_lookup_err; 832int var_skip_quit_resp; 833char *var_fallback_relay; 834char *var_bestmx_transp; 835char *var_error_rcpt; 836int var_smtp_always_ehlo; 837int var_smtp_never_ehlo; 838char *var_smtp_sasl_opts; 839char *var_smtp_sasl_path; 840char *var_smtp_sasl_passwd; 841bool var_smtp_sasl_enable; 842char *var_smtp_sasl_mechs; 843char *var_smtp_sasl_type; 844char *var_smtp_bind_addr; 845char *var_smtp_bind_addr6; 846char *var_smtp_vrfy_tgt; 847bool var_smtp_rand_addr; 848int var_smtp_pix_thresh; 849int var_queue_run_delay; 850int var_min_backoff_time; 851int var_smtp_pix_delay; 852int var_smtp_line_limit; 853char *var_smtp_helo_name; 854char *var_smtp_host_lookup; 855bool var_smtp_quote_821_env; 856bool var_smtp_defer_mxaddr; 857bool var_smtp_send_xforward; 858int var_smtp_mxaddr_limit; 859int var_smtp_mxsess_limit; 860int var_smtp_cache_conn; 861int var_smtp_reuse_time; 862int var_smtp_reuse_count; 863char *var_smtp_cache_dest; 864char *var_scache_service; /* You can now leave this here. */ 865bool var_smtp_cache_demand; 866char *var_smtp_ehlo_dis_words; 867char *var_smtp_ehlo_dis_maps; 868char *var_smtp_addr_pref; 869 870char *var_smtp_tls_level; 871bool var_smtp_use_tls; 872bool var_smtp_enforce_tls; 873char *var_smtp_tls_per_site; 874char *var_smtp_tls_policy; 875bool var_smtp_tls_wrappermode; 876 877#ifdef USE_TLS 878char *var_smtp_sasl_tls_opts; 879char *var_smtp_sasl_tlsv_opts; 880int var_smtp_starttls_tmout; 881char *var_smtp_tls_CAfile; 882char *var_smtp_tls_CApath; 883char *var_smtp_tls_cert_file; 884char *var_smtp_tls_mand_ciph; 885char *var_smtp_tls_excl_ciph; 886char *var_smtp_tls_mand_excl; 887char *var_smtp_tls_dcert_file; 888char *var_smtp_tls_dkey_file; 889bool var_smtp_tls_enforce_peername; 890char *var_smtp_tls_key_file; 891char *var_smtp_tls_loglevel; 892bool var_smtp_tls_note_starttls_offer; 893char *var_smtp_tls_mand_proto; 894char *var_smtp_tls_sec_cmatch; 895int var_smtp_tls_scert_vd; 896char *var_smtp_tls_vfy_cmatch; 897char *var_smtp_tls_fpt_cmatch; 898char *var_smtp_tls_fpt_dgst; 899char *var_smtp_tls_tafile; 900char *var_smtp_tls_proto; 901char *var_smtp_tls_ciph; 902char *var_smtp_tls_eccert_file; 903char *var_smtp_tls_eckey_file; 904bool var_smtp_tls_blk_early_mail_reply; 905bool var_smtp_tls_force_tlsa; 906char *var_smtp_tls_insecure_mx_policy; 907 908#endif 909 910char *var_smtp_generic_maps; 911char *var_prop_extension; 912bool var_smtp_sender_auth; 913char *var_lmtp_tcp_port; 914int var_scache_proto_tmout; 915bool var_smtp_cname_overr; 916char *var_smtp_pix_bug_words; 917char *var_smtp_pix_bug_maps; 918char *var_cyrus_conf_path; 919char *var_smtp_head_chks; 920char *var_smtp_mime_chks; 921char *var_smtp_nest_chks; 922char *var_smtp_body_chks; 923char *var_smtp_resp_filter; 924bool var_lmtp_assume_final; 925char *var_smtp_dns_res_opt; 926char *var_smtp_dns_support; 927bool var_smtp_rec_deadline; 928bool var_smtp_dummy_mail_auth; 929char *var_smtp_dsn_filter; 930char *var_smtp_dns_re_filter; 931 932 /* Special handling of 535 AUTH errors. */ 933char *var_smtp_sasl_auth_cache_name; 934int var_smtp_sasl_auth_cache_time; 935bool var_smtp_sasl_auth_soft_bounce; 936 937 /* 938 * Global variables. 939 */ 940int smtp_mode; 941int smtp_host_lookup_mask; 942int smtp_dns_support; 943STRING_LIST *smtp_cache_dest; 944SCACHE *smtp_scache; 945MAPS *smtp_ehlo_dis_maps; 946MAPS *smtp_generic_maps; 947int smtp_ext_prop_mask; 948unsigned smtp_dns_res_opt; 949MAPS *smtp_pix_bug_maps; 950HBC_CHECKS *smtp_header_checks; /* limited header checks */ 951HBC_CHECKS *smtp_body_checks; /* limited body checks */ 952 953#ifdef USE_TLS 954 955 /* 956 * OpenSSL client state (opaque handle) 957 */ 958TLS_APPL_STATE *smtp_tls_ctx; 959int smtp_tls_insecure_mx_policy; 960 961#endif 962 963 /* 964 * IPv6 preference. 965 */ 966static int smtp_addr_pref; 967 968/* deliver_message - deliver message with extreme prejudice */ 969 970static int deliver_message(const char *service, DELIVER_REQUEST *request) 971{ 972 SMTP_STATE *state; 973 int result; 974 975 if (msg_verbose) 976 msg_info("deliver_message: from %s", request->sender); 977 978 /* 979 * Sanity checks. The smtp server is unprivileged and chrooted, so we can 980 * afford to distribute the data censoring code, instead of having it all 981 * in one place. 982 */ 983 if (request->nexthop[0] == 0) 984 msg_fatal("empty nexthop hostname"); 985 if (request->rcpt_list.len <= 0) 986 msg_fatal("recipient count: %d", request->rcpt_list.len); 987 988 /* 989 * Initialize. Bundle all information about the delivery request, so that 990 * we can produce understandable diagnostics when something goes wrong 991 * many levels below. The alternative would be to make everything global. 992 */ 993 state = smtp_state_alloc(); 994 state->request = request; 995 state->src = request->fp; 996 state->service = service; 997 state->misc_flags |= smtp_addr_pref; 998 SMTP_RCPT_INIT(state); 999 1000 /* 1001 * Establish an SMTP session and deliver this message to all requested 1002 * recipients. At the end, notify the postmaster of any protocol errors. 1003 * Optionally deliver mail locally when this machine is the best mail 1004 * exchanger. 1005 */ 1006 result = smtp_connect(state); 1007 1008 /* 1009 * Clean up. 1010 */ 1011 smtp_state_free(state); 1012 1013 return (result); 1014} 1015 1016/* smtp_service - perform service for client */ 1017 1018static void smtp_service(VSTREAM *client_stream, char *service, char **argv) 1019{ 1020 DELIVER_REQUEST *request; 1021 int status; 1022 1023 /* 1024 * Sanity check. This service takes no command-line arguments. 1025 */ 1026 if (argv[0]) 1027 msg_fatal("unexpected command-line argument: %s", argv[0]); 1028 1029 /* 1030 * This routine runs whenever a client connects to the UNIX-domain socket 1031 * dedicated to remote SMTP delivery service. What we see below is a 1032 * little protocol to (1) tell the queue manager that we are ready, (2) 1033 * read a request from the queue manager, and (3) report the completion 1034 * status of that request. All connection-management stuff is handled by 1035 * the common code in single_server.c. 1036 */ 1037 if ((request = deliver_request_read(client_stream)) != 0) { 1038 status = deliver_message(service, request); 1039 deliver_request_done(client_stream, request, status); 1040 } 1041} 1042 1043/* post_init - post-jail initialization */ 1044 1045static void post_init(char *unused_name, char **unused_argv) 1046{ 1047 static const NAME_MASK lookup_masks[] = { 1048 SMTP_HOST_LOOKUP_DNS, SMTP_HOST_FLAG_DNS, 1049 SMTP_HOST_LOOKUP_NATIVE, SMTP_HOST_FLAG_NATIVE, 1050 0, 1051 }; 1052 static const NAME_MASK dns_res_opt_masks[] = { 1053 SMTP_DNS_RES_OPT_DEFNAMES, RES_DEFNAMES, 1054 SMTP_DNS_RES_OPT_DNSRCH, RES_DNSRCH, 1055 0, 1056 }; 1057 static const NAME_CODE dns_support[] = { 1058 SMTP_DNS_SUPPORT_DISABLED, SMTP_DNS_DISABLED, 1059 SMTP_DNS_SUPPORT_ENABLED, SMTP_DNS_ENABLED, 1060#if (RES_USE_DNSSEC != 0) && (RES_USE_EDNS0 != 0) 1061 SMTP_DNS_SUPPORT_DNSSEC, SMTP_DNS_DNSSEC, 1062#endif 1063 0, SMTP_DNS_INVALID, 1064 }; 1065 1066 if (*var_smtp_dns_support == 0) { 1067 /* Backwards compatible empty setting */ 1068 smtp_dns_support = 1069 var_disable_dns ? SMTP_DNS_DISABLED : SMTP_DNS_ENABLED; 1070 } else { 1071 smtp_dns_support = 1072 name_code(dns_support, NAME_CODE_FLAG_NONE, var_smtp_dns_support); 1073 if (smtp_dns_support == SMTP_DNS_INVALID) 1074 msg_fatal("invalid %s: \"%s\"", VAR_LMTP_SMTP(DNS_SUPPORT), 1075 var_smtp_dns_support); 1076 var_disable_dns = (smtp_dns_support == SMTP_DNS_DISABLED); 1077 } 1078 1079#ifdef USE_TLS 1080 if (smtp_mode) { 1081 smtp_tls_insecure_mx_policy = 1082 tls_level_lookup(var_smtp_tls_insecure_mx_policy); 1083 switch (smtp_tls_insecure_mx_policy) { 1084 case TLS_LEV_MAY: 1085 case TLS_LEV_ENCRYPT: 1086 case TLS_LEV_DANE: 1087 break; 1088 default: 1089 msg_fatal("invalid %s: \"%s\"", VAR_SMTP_TLS_INSECURE_MX_POLICY, 1090 var_smtp_tls_insecure_mx_policy); 1091 } 1092 } 1093#endif 1094 1095 /* 1096 * Select hostname lookup mechanisms. 1097 */ 1098 if (smtp_dns_support == SMTP_DNS_DISABLED) 1099 smtp_host_lookup_mask = SMTP_HOST_FLAG_NATIVE; 1100 else 1101 smtp_host_lookup_mask = 1102 name_mask(VAR_LMTP_SMTP(HOST_LOOKUP), lookup_masks, 1103 var_smtp_host_lookup); 1104 if (msg_verbose) 1105 msg_info("host name lookup methods: %s", 1106 str_name_mask(VAR_LMTP_SMTP(HOST_LOOKUP), lookup_masks, 1107 smtp_host_lookup_mask)); 1108 1109 /* 1110 * Session cache instance. 1111 */ 1112 if (*var_smtp_cache_dest || var_smtp_cache_demand) 1113#if 0 1114 smtp_scache = scache_multi_create(); 1115#else 1116 smtp_scache = scache_clnt_create(var_scache_service, 1117 var_scache_proto_tmout, 1118 var_ipc_idle_limit, 1119 var_ipc_ttl_limit); 1120#endif 1121 1122 /* 1123 * Select DNS query flags. 1124 */ 1125 smtp_dns_res_opt = name_mask(VAR_LMTP_SMTP(DNS_RES_OPT), dns_res_opt_masks, 1126 var_smtp_dns_res_opt); 1127 1128 /* 1129 * Address verification. 1130 */ 1131 smtp_vrfy_init(); 1132} 1133 1134/* pre_init - pre-jail initialization */ 1135 1136static void pre_init(char *unused_name, char **unused_argv) 1137{ 1138 int use_tls; 1139 static const NAME_CODE addr_pref_map[] = { 1140 INET_PROTO_NAME_IPV6, SMTP_MISC_FLAG_PREF_IPV6, 1141 INET_PROTO_NAME_IPV4, SMTP_MISC_FLAG_PREF_IPV4, 1142 INET_PROTO_NAME_ANY, 0, 1143 0, -1, 1144 }; 1145 1146 /* 1147 * Turn on per-peer debugging. 1148 */ 1149 debug_peer_init(); 1150 1151 /* 1152 * SASL initialization. 1153 */ 1154 if (var_smtp_sasl_enable) 1155#ifdef USE_SASL_AUTH 1156 smtp_sasl_initialize(); 1157#else 1158 msg_warn("%s is true, but SASL support is not compiled in", 1159 VAR_LMTP_SMTP(SASL_ENABLE)); 1160#endif 1161 1162 if (*var_smtp_tls_level != 0) 1163#ifdef USE_TLS 1164 switch (tls_level_lookup(var_smtp_tls_level)) { 1165 case TLS_LEV_SECURE: 1166 case TLS_LEV_VERIFY: 1167 case TLS_LEV_DANE_ONLY: 1168 case TLS_LEV_FPRINT: 1169 case TLS_LEV_ENCRYPT: 1170 var_smtp_use_tls = var_smtp_enforce_tls = 1; 1171 break; 1172 case TLS_LEV_DANE: 1173 case TLS_LEV_MAY: 1174 var_smtp_use_tls = 1; 1175 var_smtp_enforce_tls = 0; 1176 break; 1177 case TLS_LEV_NONE: 1178 var_smtp_use_tls = var_smtp_enforce_tls = 0; 1179 break; 1180 default: 1181 /* tls_level_lookup() logs no warning. */ 1182 /* session_tls_init() assumes that var_smtp_tls_level is sane. */ 1183 msg_fatal("Invalid TLS level \"%s\"", var_smtp_tls_level); 1184 } 1185#endif 1186 use_tls = (var_smtp_use_tls || var_smtp_enforce_tls); 1187 1188 /* 1189 * Initialize the TLS data before entering the chroot jail 1190 */ 1191 if (use_tls || var_smtp_tls_per_site[0] || var_smtp_tls_policy[0]) { 1192#ifdef USE_TLS 1193 TLS_CLIENT_INIT_PROPS props; 1194 1195 /* 1196 * We get stronger type safety and a cleaner interface by combining 1197 * the various parameters into a single tls_client_props structure. 1198 * 1199 * Large parameter lists are error-prone, so we emulate a language 1200 * feature that C does not have natively: named parameter lists. 1201 */ 1202 smtp_tls_ctx = 1203 TLS_CLIENT_INIT(&props, 1204 log_param = VAR_LMTP_SMTP(TLS_LOGLEVEL), 1205 log_level = var_smtp_tls_loglevel, 1206 verifydepth = var_smtp_tls_scert_vd, 1207 cache_type = LMTP_SMTP_SUFFIX(TLS_MGR_SCACHE), 1208 cert_file = var_smtp_tls_cert_file, 1209 key_file = var_smtp_tls_key_file, 1210 dcert_file = var_smtp_tls_dcert_file, 1211 dkey_file = var_smtp_tls_dkey_file, 1212 eccert_file = var_smtp_tls_eccert_file, 1213 eckey_file = var_smtp_tls_eckey_file, 1214 CAfile = var_smtp_tls_CAfile, 1215 CApath = var_smtp_tls_CApath, 1216 mdalg = var_smtp_tls_fpt_dgst); 1217 smtp_tls_list_init(); 1218#else 1219 msg_warn("TLS has been selected, but TLS support is not compiled in"); 1220#endif 1221 } 1222 1223 /* 1224 * Flush client. 1225 */ 1226 flush_init(); 1227 1228 /* 1229 * Session cache domain list. 1230 */ 1231 if (*var_smtp_cache_dest) 1232 smtp_cache_dest = string_list_init(VAR_SMTP_CACHE_DEST, 1233 MATCH_FLAG_RETURN, 1234 var_smtp_cache_dest); 1235 1236 /* 1237 * EHLO keyword filter. 1238 */ 1239 if (*var_smtp_ehlo_dis_maps) 1240 smtp_ehlo_dis_maps = maps_create(VAR_LMTP_SMTP(EHLO_DIS_MAPS), 1241 var_smtp_ehlo_dis_maps, 1242 DICT_FLAG_LOCK); 1243 1244 /* 1245 * PIX bug workarounds. 1246 */ 1247 if (*var_smtp_pix_bug_maps) 1248 smtp_pix_bug_maps = maps_create(VAR_LMTP_SMTP(PIX_BUG_MAPS), 1249 var_smtp_pix_bug_maps, 1250 DICT_FLAG_LOCK); 1251 1252 /* 1253 * Generic maps. 1254 */ 1255 if (*var_prop_extension) 1256 smtp_ext_prop_mask = 1257 ext_prop_mask(VAR_PROP_EXTENSION, var_prop_extension); 1258 if (*var_smtp_generic_maps) 1259 smtp_generic_maps = 1260 maps_create(VAR_LMTP_SMTP(GENERIC_MAPS), var_smtp_generic_maps, 1261 DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX 1262 | DICT_FLAG_UTF8_REQUEST); 1263 1264 /* 1265 * Header/body checks. 1266 */ 1267 smtp_header_checks = hbc_header_checks_create( 1268 VAR_LMTP_SMTP(HEAD_CHKS), var_smtp_head_chks, 1269 VAR_LMTP_SMTP(MIME_CHKS), var_smtp_mime_chks, 1270 VAR_LMTP_SMTP(NEST_CHKS), var_smtp_nest_chks, 1271 smtp_hbc_callbacks); 1272 smtp_body_checks = hbc_body_checks_create( 1273 VAR_LMTP_SMTP(BODY_CHKS), var_smtp_body_chks, 1274 smtp_hbc_callbacks); 1275 1276 /* 1277 * Server reply filter. 1278 */ 1279 if (*var_smtp_resp_filter) 1280 smtp_chat_resp_filter = 1281 dict_open(var_smtp_resp_filter, O_RDONLY, 1282 DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX); 1283 1284 /* 1285 * Address family preference. 1286 */ 1287 if (*var_smtp_addr_pref) { 1288 smtp_addr_pref = name_code(addr_pref_map, NAME_CODE_FLAG_NONE, 1289 var_smtp_addr_pref); 1290 if (smtp_addr_pref < 0) 1291 msg_fatal("bad %s value: %s", VAR_LMTP_SMTP(ADDR_PREF), 1292 var_smtp_addr_pref); 1293 } 1294 1295 /* 1296 * DNS reply filter. 1297 */ 1298 if (*var_smtp_dns_re_filter) 1299 dns_rr_filter_compile(VAR_LMTP_SMTP(DNS_RE_FILTER), 1300 var_smtp_dns_re_filter); 1301} 1302 1303/* pre_accept - see if tables have changed */ 1304 1305static void pre_accept(char *unused_name, char **unused_argv) 1306{ 1307 const char *table; 1308 1309 if ((table = dict_changed_name()) != 0) { 1310 msg_info("table %s has changed -- restarting", table); 1311 exit(0); 1312 } 1313} 1314 1315MAIL_VERSION_STAMP_DECLARE; 1316 1317/* main - pass control to the single-threaded skeleton */ 1318 1319int main(int argc, char **argv) 1320{ 1321 char *sane_procname; 1322 1323#include "smtp_params.c" 1324#include "lmtp_params.c" 1325 1326 /* 1327 * Fingerprint executables and core dumps. 1328 */ 1329 MAIL_VERSION_STAMP_ALLOCATE; 1330 1331 /* 1332 * XXX At this point, var_procname etc. are not initialized. 1333 * 1334 * The process name, "smtp" or "lmtp", determines the protocol, the DSN 1335 * server reply type, SASL service information lookup, and more. Prepare 1336 * for the possibility there may be another personality. 1337 */ 1338 sane_procname = sane_basename((VSTRING *) 0, argv[0]); 1339 if (strcmp(sane_procname, "smtp") == 0) 1340 smtp_mode = 1; 1341 else if (strcmp(sane_procname, "lmtp") == 0) 1342 smtp_mode = 0; 1343 else 1344 msg_fatal("unexpected process name \"%s\" - " 1345 "specify \"smtp\" or \"lmtp\"", var_procname); 1346 1347 /* 1348 * Initialize with the LMTP or SMTP parameter name space. 1349 */ 1350 single_server_main(argc, argv, smtp_service, 1351 CA_MAIL_SERVER_TIME_TABLE(smtp_mode ? 1352 smtp_time_table : lmtp_time_table), 1353 CA_MAIL_SERVER_INT_TABLE(smtp_mode ? 1354 smtp_int_table : lmtp_int_table), 1355 CA_MAIL_SERVER_STR_TABLE(smtp_mode ? 1356 smtp_str_table : lmtp_str_table), 1357 CA_MAIL_SERVER_BOOL_TABLE(smtp_mode ? 1358 smtp_bool_table : lmtp_bool_table), 1359 CA_MAIL_SERVER_PRE_INIT(pre_init), 1360 CA_MAIL_SERVER_POST_INIT(post_init), 1361 CA_MAIL_SERVER_PRE_ACCEPT(pre_accept), 1362 CA_MAIL_SERVER_BOUNCE_INIT(VAR_SMTP_DSN_FILTER, 1363 &var_smtp_dsn_filter), 1364 0); 1365} 1366