static int smtp_open (CONNECTION* conn) { int rc; if (mutt_socket_open (conn)) return -1; /* get greeting string */ if ((rc = smtp_get_resp (conn))) return rc; if ((rc = smtp_helo (conn))) return rc; #ifdef USE_SSL if (conn->ssf) rc = M_NO; else if (option (OPTSSLFORCETLS)) rc = M_YES; else if (mutt_bit_isset (Capabilities, STARTTLS) && (rc = query_quadoption (OPT_SSLSTARTTLS, _("Secure connection with TLS?"))) == -1) return rc; if (rc == M_YES) { if (mutt_socket_write (conn, "STARTTLS\r\n") < 0) return smtp_err_write; if ((rc = smtp_get_resp (conn))) return rc; if (mutt_ssl_starttls (conn)) { mutt_error (_("Could not negotiate TLS connection")); mutt_sleep (1); return -1; } /* re-EHLO to get authentication mechanisms */ if ((rc = smtp_helo (conn))) return rc; } #endif if (conn->account.flags & M_ACCT_USER) { if (!mutt_bit_isset (Capabilities, AUTH)) { mutt_error (_("SMTP server does not support authentication")); mutt_sleep (1); return -1; } #ifdef USE_SASL return smtp_auth (conn); #else mutt_error (_("SMTP authentication requires SASL")); mutt_sleep (1); return -1; #endif /* USE_SASL */ } return 0; }
int smtp_greet(SMTP_CLIENT *client, const char* name, int ehlo) { if (ehlo) return smtp_ehlo(client, name); else return smtp_helo(client, name); }
static void smtp_connect_inet(SMTP_STATE *state, const char *nexthop, char *def_service) { DELIVER_REQUEST *request = state->request; SMTP_ITERATOR *iter = state->iterator; ARGV *sites; char *dest; char **cpp; int non_fallback_sites; int retry_plain = 0; DSN_BUF *why = state->why; /* * For sanity, require that at least one of INET or INET6 is enabled. * Otherwise, we can't look up interface information, and we can't * convert names or addresses. */ if (inet_proto_info()->ai_family_list[0] == 0) { dsb_simple(why, "4.4.4", "all network protocols are disabled"); return; } /* * Future proofing: do a null destination sanity check in case we allow * the primary destination to be a list (it could be just separators). */ sites = argv_alloc(1); argv_add(sites, nexthop, (char *) 0); if (sites->argc == 0) msg_panic("null destination: \"%s\"", nexthop); non_fallback_sites = sites->argc; argv_split_append(sites, var_fallback_relay, CHARS_COMMA_SP); /* * Don't give up after a hard host lookup error until we have tried the * fallback relay servers. * * Don't bounce mail after a host lookup problem with a relayhost or with a * fallback relay. * * Don't give up after a qualifying soft error until we have tried all * qualifying backup mail servers. * * All this means that error handling and error reporting depends on whether * the error qualifies for trying to deliver to a backup mail server, or * whether we're looking up a relayhost or fallback relay. The challenge * then is to build this into the pre-existing SMTP client without * getting lost in the complexity. */ #define IS_FALLBACK_RELAY(cpp, sites, non_fallback_sites) \ (*(cpp) && (cpp) >= (sites)->argv + (non_fallback_sites)) for (cpp = sites->argv, (state->misc_flags |= SMTP_MISC_FLAG_FIRST_NEXTHOP); SMTP_RCPT_LEFT(state) > 0 && (dest = *cpp) != 0; cpp++, (state->misc_flags &= ~SMTP_MISC_FLAG_FIRST_NEXTHOP)) { char *dest_buf; char *domain; unsigned port; DNS_RR *addr_list; DNS_RR *addr; DNS_RR *next; int addr_count; int sess_count; SMTP_SESSION *session; int lookup_mx; unsigned domain_best_pref; MAI_HOSTADDR_STR hostaddr; if (cpp[1] == 0) state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP; /* * Parse the destination. If no TCP port is specified, use the port * that is reserved for the protocol (SMTP or LMTP). */ dest_buf = smtp_parse_destination(dest, def_service, &domain, &port); if (var_helpful_warnings && var_smtp_tls_wrappermode == 0 && ntohs(port) == 465) { msg_info("SMTPS wrappermode (TCP port 465) requires setting " "\"%s = yes\", and \"%s = encrypt\" (or stronger)", VAR_LMTP_SMTP(TLS_WRAPPER), VAR_LMTP_SMTP(TLS_LEVEL)); } #define NO_HOST "" /* safety */ #define NO_ADDR "" /* safety */ SMTP_ITER_INIT(iter, dest, NO_HOST, NO_ADDR, port, state); /* * Resolve an SMTP or LMTP server. In the case of SMTP, skip mail * exchanger lookups when a quoted host is specified or when DNS * lookups are disabled. */ if (msg_verbose) msg_info("connecting to %s port %d", domain, ntohs(port)); if (smtp_mode) { if (ntohs(port) == IPPORT_SMTP) state->misc_flags |= SMTP_MISC_FLAG_LOOP_DETECT; else state->misc_flags &= ~SMTP_MISC_FLAG_LOOP_DETECT; lookup_mx = (smtp_dns_support != SMTP_DNS_DISABLED && *dest != '['); } else lookup_mx = 0; if (!lookup_mx) { addr_list = smtp_host_addr(domain, state->misc_flags, why); /* XXX We could be an MX host for this destination... */ } else { int i_am_mx = 0; addr_list = smtp_domain_addr(domain, &iter->mx, state->misc_flags, why, &i_am_mx); /* If we're MX host, don't connect to non-MX backups. */ if (i_am_mx) state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP; } /* * Don't try fall-back hosts if mail loops to myself. That would just * make the problem worse. */ if (addr_list == 0 && SMTP_HAS_LOOP_DSN(why)) state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP; /* * No early loop exit or we have a memory leak with dest_buf. */ if (addr_list) domain_best_pref = addr_list->pref; /* * When session caching is enabled, store the first good session for * this delivery request under the next-hop destination name. All * good sessions will be stored under their specific server IP * address. * * XXX smtp_session_cache_destinations specifies domain names without * :port, because : is already used for maptype:mapname. Because of * this limitation we use the bare domain without the optional [] or * non-default TCP port. * * Opportunistic (a.k.a. on-demand) session caching on request by the * queue manager. This is turned temporarily when a destination has a * high volume of mail in the active queue. When the surge reaches * its end, the queue manager requests that connections be retrieved * but not stored. */ if (addr_list && (state->misc_flags & SMTP_MISC_FLAG_FIRST_NEXTHOP)) { smtp_cache_policy(state, domain); if (state->misc_flags & SMTP_MISC_FLAG_CONN_CACHE_MASK) SET_NEXTHOP_STATE(state, dest); } /* * Delete visited cached hosts from the address list. * * Optionally search the connection cache by domain name or by primary * MX address before we try to create new connections. * * Enforce the MX session and MX address counts per next-hop or * fall-back destination. smtp_reuse_session() will truncate the * address list when either limit is reached. */ if (addr_list && (state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD)) { if (state->cache_used->used > 0) smtp_scrub_addr_list(state->cache_used, &addr_list); sess_count = addr_count = smtp_reuse_session(state, &addr_list, domain_best_pref); } else sess_count = addr_count = 0; /* * Connect to an SMTP server: create primary MX connections, and * reuse or create backup MX connections. * * At the start of an SMTP session, all recipients are unmarked. In the * course of an SMTP session, recipients are marked as KEEP (deliver * to alternate mail server) or DROP (remove from recipient list). At * the end of an SMTP session, weed out the recipient list. Unmark * any left-over recipients and try to deliver them to a backup mail * server. * * Cache the first good session under the next-hop destination name. * Cache all good sessions under their physical endpoint. * * Don't query the session cache for primary MX hosts. We already did * that in smtp_reuse_session(), and if any were found in the cache, * they were already deleted from the address list. * * Currently, we use smtp_reuse_addr() only for SASL-unauthenticated * connections. Furthermore, we rely on smtp_reuse_addr() to look up * an existing SASL-unauthenticated connection only when a new * connection would be guaranteed not to require SASL authentication. * * In addition, we rely on smtp_reuse_addr() to look up an existing * plaintext connection only when a new connection would be * guaranteed not to use TLS. */ for (addr = addr_list; SMTP_RCPT_LEFT(state) > 0 && addr; addr = next) { next = addr->next; if (++addr_count == var_smtp_mxaddr_limit) next = 0; if (dns_rr_to_pa(addr, &hostaddr) == 0) { msg_warn("cannot convert type %s record to printable address", dns_strtype(addr->type)); /* XXX Assume there is no code at the end of this loop. */ continue; } vstring_strcpy(iter->addr, hostaddr.buf); vstring_strcpy(iter->host, SMTP_HNAME(addr)); iter->rr = addr; #ifdef USE_TLS if (!smtp_tls_policy_cache_query(why, state->tls, iter)) { msg_warn("TLS policy lookup for %s/%s: %s", STR(iter->dest), STR(iter->host), STR(why->reason)); continue; /* XXX Assume there is no code at the end of this loop. */ } if (var_smtp_tls_wrappermode && state->tls->level < TLS_LEV_ENCRYPT) { msg_warn("%s requires \"%s = encrypt\" (or stronger)", VAR_LMTP_SMTP(TLS_WRAPPER), VAR_LMTP_SMTP(TLS_LEVEL)); continue; /* XXX Assume there is no code at the end of this loop. */ } /* Disable TLS when retrying after a handshake failure */ if (retry_plain) { state->tls->level = TLS_LEV_NONE; retry_plain = 0; } #endif if ((state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD) == 0 || addr->pref == domain_best_pref || !(session = smtp_reuse_addr(state, SMTP_KEY_MASK_SCACHE_ENDP_LABEL))) session = smtp_connect_addr(iter, why, state->misc_flags); if ((state->session = session) != 0) { session->state = state; #ifdef USE_TLS session->tls_nexthop = domain; #endif if (addr->pref == domain_best_pref) session->features |= SMTP_FEATURE_BEST_MX; /* Don't count handshake errors towards the session limit. */ if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP) && next == 0) state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER; if ((session->features & SMTP_FEATURE_FROM_CACHE) == 0 && smtp_helo(state) != 0) { #ifdef USE_TLS /* * When an opportunistic TLS handshake fails, try the * same address again, with TLS disabled. See also the * RETRY_AS_PLAINTEXT macro. */ if ((retry_plain = session->tls_retry_plain) != 0) { --addr_count; next = addr; } #endif /* * When a TLS handshake fails, the stream is marked * "dead" to avoid further I/O over a broken channel. */ if (!THIS_SESSION_IS_FORBIDDEN && vstream_ferror(session->stream) == 0 && vstream_feof(session->stream) == 0) smtp_quit(state); } else { /* Do count delivery errors towards the session limit. */ if (++sess_count == var_smtp_mxsess_limit) next = 0; if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP) && next == 0) state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER; smtp_xfer(state); #ifdef USE_TLS /* * When opportunistic TLS fails after the STARTTLS * handshake, try the same address again, with TLS * disabled. See also the RETRY_AS_PLAINTEXT macro. */ if ((retry_plain = session->tls_retry_plain) != 0) { --sess_count; --addr_count; next = addr; } #endif } smtp_cleanup_session(state); } else { /* The reason already includes the IP address and TCP port. */ msg_info("%s", STR(why->reason)); } /* XXX Code above assumes there is no code at this loop ending. */ } dns_rr_free(addr_list); if (iter->mx) { dns_rr_free(iter->mx); iter->mx = 0; /* Just in case */ } myfree(dest_buf); if (state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP) break; } /* * We still need to deliver, bounce or defer some left-over recipients: * either mail loops or some backup mail server was unavailable. */ if (SMTP_RCPT_LEFT(state) > 0) { /* * In case of a "no error" indication we make up an excuse: we did * find the host address, but we did not attempt to connect to it. * This can happen when the fall-back relay was already tried via a * cached connection, so that the address list scrubber left behind * an empty list. */ if (!SMTP_HAS_DSN(why)) { dsb_simple(why, "4.3.0", "server unavailable or unable to receive mail"); } /* * Pay attention to what could be configuration problems, and pretend * that these are recoverable rather than bouncing the mail. */ else if (!SMTP_HAS_SOFT_DSN(why)) { /* * The fall-back destination did not resolve as expected, or it * is refusing to talk to us, or mail for it loops back to us. */ if (IS_FALLBACK_RELAY(cpp, sites, non_fallback_sites)) { msg_warn("%s configuration problem", VAR_SMTP_FALLBACK); vstring_strcpy(why->status, "4.3.5"); /* XXX Keep the diagnostic code and MTA. */ } /* * The next-hop relayhost did not resolve as expected, or it is * refusing to talk to us, or mail for it loops back to us. * * XXX There is no equivalent safety net for mis-configured * sender-dependent relay hosts. The trivial-rewrite resolver * would have to flag the result, and the queue manager would * have to provide that information to delivery agents. */ else if (smtp_mode && strcmp(sites->argv[0], var_relayhost) == 0) { msg_warn("%s configuration problem", VAR_RELAYHOST); vstring_strcpy(why->status, "4.3.5"); /* XXX Keep the diagnostic code and MTA. */ } /* * Mail for the next-hop destination loops back to myself. Pass * the mail to the best_mx_transport or bounce it. */ else if (smtp_mode && SMTP_HAS_LOOP_DSN(why) && *var_bestmx_transp) { dsb_reset(why); /* XXX */ state->status = deliver_pass_all(MAIL_CLASS_PRIVATE, var_bestmx_transp, request); SMTP_RCPT_LEFT(state) = 0; /* XXX */ } } } /* * Cleanup. */ if (HAVE_NEXTHOP_STATE(state)) FREE_NEXTHOP_STATE(state); argv_free(sites); }
static void smtp_connect_local(SMTP_STATE *state, const char *path) { const char *myname = "smtp_connect_local"; SMTP_ITERATOR *iter = state->iterator; SMTP_SESSION *session; DSN_BUF *why = state->why; /* * Do not silently ignore an unused setting. */ if (*var_fallback_relay) msg_warn("ignoring \"%s = %s\" setting for non-TCP connections", VAR_LMTP_FALLBACK, var_fallback_relay); /* * It's too painful to weave this code into the SMTP connection * management routine. * * Connection cache management is based on the UNIX-domain pathname, without * the "unix:" prefix. */ smtp_cache_policy(state, path); /* * Here we ensure that the iter->addr member refers to a copy of the * UNIX-domain pathname, so that smtp_save_session() will cache the * connection using the pathname as the physical endpoint name. * * We set dest=path for backwards compatibility. */ #define NO_PORT 0 SMTP_ITER_INIT(iter, path, var_myhostname, path, NO_PORT, state); /* * Opportunistic TLS for unix domain sockets does not make much sense, * since the channel is private, mere encryption without authentication * is just wasted cycles and opportunity for breakage. Since we are not * willing to retry after TLS handshake failures here, we downgrade "may" * no "none". Nothing is lost, and much waste is avoided. * * We don't know who is authenticating whom, so if a client cert is * available, "encrypt" may be a sensible policy. Otherwise, we also * downgrade "encrypt" to "none", this time just to avoid waste. * * We use smtp_reuse_nexthop() instead of smtp_reuse_addr(), so that we can * reuse a SASL-authenticated connection (however unlikely this scenario * may be). The smtp_reuse_addr() interface currently supports only reuse * of SASL-unauthenticated connections. */ #ifdef USE_TLS if (!smtp_tls_policy_cache_query(why, state->tls, iter)) { msg_warn("TLS policy lookup error for %s/%s: %s", STR(iter->host), STR(iter->addr), STR(why->reason)); return; } #endif if ((state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD) == 0 || (session = smtp_reuse_nexthop(state, SMTP_KEY_MASK_SCACHE_DEST_LABEL)) == 0) session = smtp_connect_unix(iter, why, state->misc_flags); if ((state->session = session) != 0) { session->state = state; #ifdef USE_TLS session->tls_nexthop = var_myhostname; /* for TLS_LEV_SECURE */ if (state->tls->level == TLS_LEV_MAY) { msg_warn("%s: opportunistic TLS encryption is not appropriate " "for unix-domain destinations.", myname); state->tls->level = TLS_LEV_NONE; } #endif /* All delivery errors bounce or defer. */ state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER; /* * When a TLS handshake fails, the stream is marked "dead" to avoid * further I/O over a broken channel. */ if ((session->features & SMTP_FEATURE_FROM_CACHE) == 0 && smtp_helo(state) != 0) { if (!THIS_SESSION_IS_FORBIDDEN && vstream_ferror(session->stream) == 0 && vstream_feof(session->stream) == 0) smtp_quit(state); } else { smtp_xfer(state); } /* * With opportunistic TLS disabled we don't expect to be asked to * retry connections without TLS, and so we expect the final server * flag to stay on. */ if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_SERVER) == 0) msg_panic("%s: unix-domain destination not final!", myname); smtp_cleanup_session(state); } }
static gint smtp_session_recv_msg(Session *session, const gchar *msg) { SMTPSession *smtp_session = SMTP_SESSION(session); gboolean cont = FALSE; if (strlen(msg) < 4) { log_warning(_("bad SMTP response\n")); return -1; } switch (smtp_session->state) { case SMTP_EHLO: case SMTP_STARTTLS: case SMTP_AUTH: case SMTP_AUTH_PLAIN: case SMTP_AUTH_LOGIN_USER: case SMTP_AUTH_LOGIN_PASS: case SMTP_AUTH_CRAM_MD5: log_print("ESMTP< %s\n", msg); break; default: log_print("SMTP< %s\n", msg); break; } if (msg[0] == '5' && msg[1] == '0' && (msg[2] == '4' || msg[2] == '3' || msg[2] == '1')) { log_warning(_("error occurred on SMTP session\n")); smtp_session->state = SMTP_ERROR; smtp_session->error_val = SM_ERROR; g_free(smtp_session->error_msg); smtp_session->error_msg = g_strdup(msg); return -1; } if (!strncmp(msg, "535", 3)) { log_warning(_("error occurred on authentication\n")); smtp_session->state = SMTP_ERROR; smtp_session->error_val = SM_AUTHFAIL; g_free(smtp_session->error_msg); smtp_session->error_msg = g_strdup(msg); return -1; } if (msg[0] != '1' && msg[0] != '2' && msg[0] != '3') { log_warning(_("error occurred on SMTP session\n")); smtp_session->state = SMTP_ERROR; smtp_session->error_val = SM_ERROR; g_free(smtp_session->error_msg); smtp_session->error_msg = g_strdup(msg); return -1; } if (msg[3] == '-') cont = TRUE; else if (msg[3] != ' ' && msg[3] != '\0') { log_warning(_("bad SMTP response\n")); smtp_session->state = SMTP_ERROR; smtp_session->error_val = SM_UNRECOVERABLE; return -1; } /* ignore all multiline responses except for EHLO */ if (cont && smtp_session->state != SMTP_EHLO) return session_recv_msg(session); switch (smtp_session->state) { case SMTP_READY: if (strstr(msg, "ESMTP")) smtp_session->is_esmtp = TRUE; case SMTP_CONNECTED: #if USE_OPENSSL if (smtp_session->user || session->ssl_type != SSL_NONE || smtp_session->is_esmtp) #else if (smtp_session->user || smtp_session->is_esmtp) #endif smtp_ehlo(smtp_session); else smtp_helo(smtp_session); break; case SMTP_HELO: smtp_from(smtp_session); break; case SMTP_EHLO: smtp_ehlo_recv(smtp_session, msg); if (cont == TRUE) break; if (smtp_session->max_message_size > 0 && smtp_session->max_message_size < smtp_session->send_data_len) { log_warning(_("Message is too big " "(Maximum size is %s)\n"), to_human_readable( (off_t)(smtp_session->max_message_size))); smtp_session->state = SMTP_ERROR; smtp_session->error_val = SM_ERROR; return -1; } #if USE_OPENSSL if (session->ssl_type == SSL_STARTTLS && smtp_session->tls_init_done == FALSE) { smtp_starttls(smtp_session); break; } #endif if (smtp_session->user) { if (smtp_auth(smtp_session) != SM_OK) smtp_from(smtp_session); } else smtp_from(smtp_session); break; case SMTP_STARTTLS: #if USE_OPENSSL if (session_start_tls(session) < 0) { log_warning(_("can't start TLS session\n")); smtp_session->state = SMTP_ERROR; smtp_session->error_val = SM_ERROR; return -1; } smtp_session->tls_init_done = TRUE; smtp_ehlo(smtp_session); #endif break; case SMTP_AUTH: smtp_auth_recv(smtp_session, msg); break; case SMTP_AUTH_LOGIN_USER: smtp_auth_login_user_recv(smtp_session, msg); break; case SMTP_AUTH_PLAIN: case SMTP_AUTH_LOGIN_PASS: case SMTP_AUTH_CRAM_MD5: smtp_from(smtp_session); break; case SMTP_FROM: if (smtp_session->cur_to) smtp_rcpt(smtp_session); break; case SMTP_RCPT: if (smtp_session->cur_to) smtp_rcpt(smtp_session); else smtp_data(smtp_session); break; case SMTP_DATA: smtp_send_data(smtp_session); break; case SMTP_EOM: smtp_quit(smtp_session); break; case SMTP_QUIT: session_disconnect(session); break; case SMTP_ERROR: default: log_warning(_("error occurred on SMTP session\n")); smtp_session->error_val = SM_ERROR; return -1; } if (cont) return session_recv_msg(session); return 0; }
static void smtp_connect_remote(SMTP_STATE *state, const char *nexthop, char *def_service) { DELIVER_REQUEST *request = state->request; ARGV *sites; char *dest; char **cpp; int non_fallback_sites; int retry_plain = 0; DSN_BUF *why = state->why; /* * First try to deliver to the indicated destination, then try to deliver * to the optional fall-back relays. * * Future proofing: do a null destination sanity check in case we allow the * primary destination to be a list (it could be just separators). */ sites = argv_alloc(1); argv_add(sites, nexthop, (char *) 0); if (sites->argc == 0) msg_panic("null destination: \"%s\"", nexthop); non_fallback_sites = sites->argc; if ((state->misc_flags & SMTP_MISC_FLAG_USE_LMTP) == 0) argv_split_append(sites, var_fallback_relay, ", \t\r\n"); /* * Don't give up after a hard host lookup error until we have tried the * fallback relay servers. * * Don't bounce mail after a host lookup problem with a relayhost or with a * fallback relay. * * Don't give up after a qualifying soft error until we have tried all * qualifying backup mail servers. * * All this means that error handling and error reporting depends on whether * the error qualifies for trying to deliver to a backup mail server, or * whether we're looking up a relayhost or fallback relay. The challenge * then is to build this into the pre-existing SMTP client without * getting lost in the complexity. */ #define IS_FALLBACK_RELAY(cpp, sites, non_fallback_sites) \ (*(cpp) && (cpp) >= (sites)->argv + (non_fallback_sites)) for (cpp = sites->argv, (state->misc_flags |= SMTP_MISC_FLAG_FIRST_NEXTHOP); SMTP_RCPT_LEFT(state) > 0 && (dest = *cpp) != 0; cpp++, (state->misc_flags &= ~SMTP_MISC_FLAG_FIRST_NEXTHOP)) { char *dest_buf; char *domain; unsigned port; DNS_RR *addr_list; DNS_RR *addr; DNS_RR *next; int addr_count; int sess_count; SMTP_SESSION *session; int lookup_mx; unsigned domain_best_pref; MAI_HOSTADDR_STR hostaddr; if (cpp[1] == 0) state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP; /* * Parse the destination. Default is to use the SMTP port. Look up * the address instead of the mail exchanger when a quoted host is * specified, or when DNS lookups are disabled. */ dest_buf = smtp_parse_destination(dest, def_service, &domain, &port); if (var_helpful_warnings && ntohs(port) == 465) { msg_info("CLIENT wrappermode (port smtps/465) is unimplemented"); msg_info("instead, send to (port submission/587) with STARTTLS"); } /* * Resolve an SMTP server. Skip mail exchanger lookups when a quoted * host is specified, or when DNS lookups are disabled. */ if (msg_verbose) msg_info("connecting to %s port %d", domain, ntohs(port)); if ((state->misc_flags & SMTP_MISC_FLAG_USE_LMTP) == 0) { if (ntohs(port) == IPPORT_SMTP) state->misc_flags |= SMTP_MISC_FLAG_LOOP_DETECT; else state->misc_flags &= ~SMTP_MISC_FLAG_LOOP_DETECT; lookup_mx = (var_disable_dns == 0 && *dest != '['); } else lookup_mx = 0; if (!lookup_mx) { addr_list = smtp_host_addr(domain, state->misc_flags, why); /* XXX We could be an MX host for this destination... */ } else { int i_am_mx = 0; addr_list = smtp_domain_addr(domain, state->misc_flags, why, &i_am_mx); /* If we're MX host, don't connect to non-MX backups. */ if (i_am_mx) state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP; } /* * Don't try fall-back hosts if mail loops to myself. That would just * make the problem worse. */ if (addr_list == 0 && SMTP_HAS_LOOP_DSN(why)) state->misc_flags |= SMTP_MISC_FLAG_FINAL_NEXTHOP; /* * No early loop exit or we have a memory leak with dest_buf. */ if (addr_list) domain_best_pref = addr_list->pref; /* * When session caching is enabled, store the first good session for * this delivery request under the next-hop destination name. All * good sessions will be stored under their specific server IP * address. * * XXX Replace sites->argv by (lookup_mx, domain, port) triples so we * don't have to make clumsy ad-hoc copies and keep track of who * free()s the memory. * * XXX smtp_session_cache_destinations specifies domain names without * :port, because : is already used for maptype:mapname. Because of * this limitation we use the bare domain without the optional [] or * non-default TCP port. * * Opportunistic (a.k.a. on-demand) session caching on request by the * queue manager. This is turned temporarily when a destination has a * high volume of mail in the active queue. * * XXX Disable connection caching when sender-dependent authentication * is enabled. We must not send someone elses mail over an * authenticated connection, and we must not send mail that requires * authentication over a connection that wasn't authenticated. */ if (addr_list && (state->misc_flags & SMTP_MISC_FLAG_FIRST_NEXTHOP)) { smtp_cache_policy(state, domain); if (state->misc_flags & SMTP_MISC_FLAG_CONN_STORE) SET_NEXTHOP_STATE(state, lookup_mx, domain, port); } /* * Delete visited cached hosts from the address list. * * Optionally search the connection cache by domain name or by primary * MX address before we try to create new connections. * * Enforce the MX session and MX address counts per next-hop or * fall-back destination. smtp_reuse_session() will truncate the * address list when either limit is reached. */ if (addr_list && (state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD)) { if (state->cache_used->used > 0) smtp_scrub_addr_list(state->cache_used, &addr_list); sess_count = addr_count = smtp_reuse_session(state, lookup_mx, domain, port, &addr_list, domain_best_pref); } else sess_count = addr_count = 0; /* * Connect to an SMTP server: create primary MX connections, and * reuse or create backup MX connections. * * At the start of an SMTP session, all recipients are unmarked. In the * course of an SMTP session, recipients are marked as KEEP (deliver * to alternate mail server) or DROP (remove from recipient list). At * the end of an SMTP session, weed out the recipient list. Unmark * any left-over recipients and try to deliver them to a backup mail * server. * * Cache the first good session under the next-hop destination name. * Cache all good sessions under their physical endpoint. * * Don't query the session cache for primary MX hosts. We already did * that in smtp_reuse_session(), and if any were found in the cache, * they were already deleted from the address list. */ for (addr = addr_list; SMTP_RCPT_LEFT(state) > 0 && addr; addr = next) { next = addr->next; if (++addr_count == var_smtp_mxaddr_limit) next = 0; if ((state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD) == 0 || addr->pref == domain_best_pref || dns_rr_to_pa(addr, &hostaddr) == 0 || !(session = smtp_reuse_addr(state, hostaddr.buf, port))) session = smtp_connect_addr(dest, addr, port, why, state->misc_flags); if ((state->session = session) != 0) { session->state = state; if (addr->pref == domain_best_pref) session->features |= SMTP_FEATURE_BEST_MX; /* Don't count handshake errors towards the session limit. */ if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP) && next == 0) state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER; #ifdef USE_TLS /* Disable TLS when retrying after a handshake failure */ if (retry_plain) { if (session->tls_level >= TLS_LEV_ENCRYPT) msg_panic("Plain-text retry wrong for mandatory TLS"); session->tls_level = TLS_LEV_NONE; retry_plain = 0; } session->tls_nexthop = domain; /* for TLS_LEV_SECURE */ #endif if ((session->features & SMTP_FEATURE_FROM_CACHE) == 0 && smtp_helo(state) != 0) { #ifdef USE_TLS /* * When an opportunistic TLS handshake fails, try the * same address again, with TLS disabled. See also the * RETRY_AS_PLAINTEXT macro. */ if ((retry_plain = session->tls_retry_plain) != 0) { --addr_count; next = addr; } #endif /* * When a TLS handshake fails, the stream is marked * "dead" to avoid further I/O over a broken channel. */ if (!THIS_SESSION_IS_DEAD && vstream_ferror(session->stream) == 0 && vstream_feof(session->stream) == 0) smtp_quit(state); } else { /* Do count delivery errors towards the session limit. */ if (++sess_count == var_smtp_mxsess_limit) next = 0; if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP) && next == 0) state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER; smtp_xfer(state); } smtp_cleanup_session(state); } else { /* The reason already includes the IP address and TCP port. */ msg_info("%s", STR(why->reason)); } /* Insert: test if we must skip the remaining MX hosts. */ } dns_rr_free(addr_list); myfree(dest_buf); if (state->misc_flags & SMTP_MISC_FLAG_FINAL_NEXTHOP) break; } /* * We still need to deliver, bounce or defer some left-over recipients: * either mail loops or some backup mail server was unavailable. */ if (SMTP_RCPT_LEFT(state) > 0) { /* * In case of a "no error" indication we make up an excuse: we did * find the host address, but we did not attempt to connect to it. * This can happen when the fall-back relay was already tried via a * cached connection, so that the address list scrubber left behind * an empty list. */ if (!SMTP_HAS_DSN(why)) { dsb_simple(why, "4.3.0", "server unavailable or unable to receive mail"); } /* * Pay attention to what could be configuration problems, and pretend * that these are recoverable rather than bouncing the mail. */ else if (!SMTP_HAS_SOFT_DSN(why) && (state->misc_flags & SMTP_MISC_FLAG_USE_LMTP) == 0) { /* * The fall-back destination did not resolve as expected, or it * is refusing to talk to us, or mail for it loops back to us. */ if (IS_FALLBACK_RELAY(cpp, sites, non_fallback_sites)) { msg_warn("%s configuration problem", VAR_SMTP_FALLBACK); vstring_strcpy(why->status, "4.3.5"); /* XXX Keep the diagnostic code and MTA. */ } /* * The next-hop relayhost did not resolve as expected, or it is * refusing to talk to us, or mail for it loops back to us. */ else if (strcmp(sites->argv[0], var_relayhost) == 0) { msg_warn("%s configuration problem", VAR_RELAYHOST); vstring_strcpy(why->status, "4.3.5"); /* XXX Keep the diagnostic code and MTA. */ } /* * Mail for the next-hop destination loops back to myself. Pass * the mail to the best_mx_transport or bounce it. */ else if (SMTP_HAS_LOOP_DSN(why) && *var_bestmx_transp) { dsb_reset(why); /* XXX */ state->status = deliver_pass_all(MAIL_CLASS_PRIVATE, var_bestmx_transp, request); SMTP_RCPT_LEFT(state) = 0; /* XXX */ } } } /* * Cleanup. */ if (HAVE_NEXTHOP_STATE(state)) FREE_NEXTHOP_STATE(state); argv_free(sites); }
static void smtp_connect_local(SMTP_STATE *state, const char *path) { const char *myname = "smtp_connect_local"; SMTP_SESSION *session; DSN_BUF *why = state->why; /* * It's too painful to weave this code into the SMTP connection * management routine. * * Connection cache management is based on the UNIX-domain pathname, without * the "unix:" prefix. */ smtp_cache_policy(state, path); /* * XXX We assume that the session->addr member refers to a copy of the * UNIX-domain pathname, so that smtp_save_session() will cache the * connection using the pathname as the physical endpoint name. */ #define NO_PORT 0 /* * Opportunistic TLS for unix domain sockets does not make much sense, * since the channel is private, mere encryption without authentication * is just wasted cycles and opportunity for breakage. Since we are not * willing to retry after TLS handshake failures here, we downgrade "may" * no "none". Nothing is lost, and much waste is avoided. * * We don't know who is authenticating whom, so if a client cert is * available, "encrypt" may be a sensible policy. Otherwise, we also * downgrade "encrypt" to "none", this time just to avoid waste. */ if ((state->misc_flags & SMTP_MISC_FLAG_CONN_LOAD) == 0 || (session = smtp_reuse_addr(state, path, NO_PORT)) == 0) session = smtp_connect_unix(path, why, state->misc_flags); if ((state->session = session) != 0) { session->state = state; #ifdef USE_TLS session->tls_nexthop = var_myhostname; /* for TLS_LEV_SECURE */ if (session->tls_level == TLS_LEV_MAY) { msg_warn("%s: opportunistic TLS encryption is not appropriate " "for unix-domain destinations.", myname); session->tls_level = TLS_LEV_NONE; } #endif /* All delivery errors bounce or defer. */ state->misc_flags |= SMTP_MISC_FLAG_FINAL_SERVER; /* * When a TLS handshake fails, the stream is marked "dead" to avoid * further I/O over a broken channel. */ if ((session->features & SMTP_FEATURE_FROM_CACHE) == 0 && smtp_helo(state) != 0) { if (!THIS_SESSION_IS_DEAD && vstream_ferror(session->stream) == 0 && vstream_feof(session->stream) == 0) smtp_quit(state); } else { smtp_xfer(state); } /* * With opportunistic TLS disabled we don't expect to be asked to * retry connections without TLS, and so we expect the final server * flag to stay on. */ if ((state->misc_flags & SMTP_MISC_FLAG_FINAL_SERVER) == 0) msg_panic("%s: unix-domain destination not final!", myname); smtp_cleanup_session(state); } }
static gboolean connect_to_server (CamelService *service, GCancellable *cancellable, GError **error) { CamelSmtpTransport *transport = CAMEL_SMTP_TRANSPORT (service); CamelNetworkSettings *network_settings; CamelNetworkSecurityMethod method; CamelSettings *settings; CamelStream *stream; GIOStream *base_stream; GIOStream *tls_stream; gchar *respbuf = NULL; gboolean success = TRUE; gchar *host; if (!CAMEL_SERVICE_CLASS (camel_smtp_transport_parent_class)-> connect_sync (service, cancellable, error)) return FALSE; /* set some smtp transport defaults */ transport->flags = 0; transport->authtypes = NULL; settings = camel_service_ref_settings (service); network_settings = CAMEL_NETWORK_SETTINGS (settings); host = camel_network_settings_dup_host (network_settings); method = camel_network_settings_get_security_method (network_settings); g_object_unref (settings); base_stream = camel_network_service_connect_sync ( CAMEL_NETWORK_SERVICE (service), cancellable, error); if (base_stream != NULL) { /* get the localaddr - needed later by smtp_helo */ transport->local_address = g_socket_connection_get_local_address ( G_SOCKET_CONNECTION (base_stream), NULL); stream = camel_stream_new (base_stream); g_object_unref (base_stream); } else { success = FALSE; goto exit; } transport->connected = TRUE; transport->ostream = stream; transport->istream = camel_stream_buffer_new ( stream, CAMEL_STREAM_BUFFER_READ); /* Read the greeting, note whether the server is ESMTP or not. */ do { /* Check for "220" */ g_free (respbuf); respbuf = camel_stream_buffer_read_line ( CAMEL_STREAM_BUFFER (transport->istream), cancellable, error); d (fprintf (stderr, "[SMTP] received: %s\n", respbuf ? respbuf : "(null)")); if (respbuf == NULL) { g_prefix_error (error, _("Welcome response error: ")); transport->connected = FALSE; success = FALSE; goto exit; } if (strncmp (respbuf, "220", 3)) { smtp_set_error ( transport, respbuf, cancellable, error); g_prefix_error (error, _("Welcome response error: ")); g_free (respbuf); success = FALSE; goto exit; } } while (*(respbuf+3) == '-'); /* if we got "220-" then loop again */ g_free (respbuf); /* Try sending EHLO */ transport->flags |= CAMEL_SMTP_TRANSPORT_IS_ESMTP; if (!smtp_helo (transport, cancellable, error)) { if (!transport->connected) { success = FALSE; goto exit; } /* Fall back to HELO */ g_clear_error (error); transport->flags &= ~CAMEL_SMTP_TRANSPORT_IS_ESMTP; if (!smtp_helo (transport, cancellable, error)) { success = FALSE; goto exit; } } /* Clear any EHLO/HELO exception and assume that * any SMTP errors encountered were non-fatal. */ g_clear_error (error); if (method != CAMEL_NETWORK_SECURITY_METHOD_STARTTLS_ON_STANDARD_PORT) goto exit; /* we're done */ if (!(transport->flags & CAMEL_SMTP_TRANSPORT_STARTTLS)) { g_set_error ( error, CAMEL_ERROR, CAMEL_ERROR_GENERIC, _("Failed to connect to SMTP server %s in secure mode: %s"), host, _("STARTTLS not supported")); success = FALSE; goto exit; } d (fprintf (stderr, "[SMTP] sending: STARTTLS\r\n")); if (camel_stream_write ( stream, "STARTTLS\r\n", 10, cancellable, error) == -1) { g_prefix_error (error, _("STARTTLS command failed: ")); success = FALSE; goto exit; } respbuf = NULL; do { /* Check for "220 Ready for TLS" */ g_free (respbuf); respbuf = camel_stream_buffer_read_line ( CAMEL_STREAM_BUFFER (transport->istream), cancellable, error); d (fprintf (stderr, "[SMTP] received: %s\n", respbuf ? respbuf : "(null)")); if (respbuf == NULL) { g_prefix_error (error, _("STARTTLS command failed: ")); transport->connected = FALSE; success = FALSE; goto exit; } if (strncmp (respbuf, "220", 3) != 0) { smtp_set_error ( transport, respbuf, cancellable, error); g_prefix_error (error, _("STARTTLS command failed: ")); g_free (respbuf); success = FALSE; goto exit; } } while (*(respbuf+3) == '-'); /* if we got "220-" then loop again */ /* Okay, now toggle SSL/TLS mode */ base_stream = camel_stream_ref_base_stream (stream); tls_stream = camel_network_service_starttls ( CAMEL_NETWORK_SERVICE (service), base_stream, error); g_object_unref (base_stream); if (tls_stream != NULL) { camel_stream_set_base_stream (stream, tls_stream); g_object_unref (tls_stream); } else { g_prefix_error ( error, _("Failed to connect to SMTP server %s in secure mode: "), host); success = FALSE; goto exit; } /* We are supposed to re-EHLO after a successful STARTTLS to * re-fetch any supported extensions. */ if (!smtp_helo (transport, cancellable, error)) { success = FALSE; } exit: g_free (host); if (!success) { transport->connected = FALSE; g_clear_object (&transport->istream); g_clear_object (&transport->ostream); } return success; }