+ /* Unless ssl-on-connect, wait for the initial greeting */
+ smtps_redo_greeting:
+
+ #ifdef SUPPORT_TLS
+ if (!smtps || (smtps && tls_out.active >= 0))
+ #endif
+ if (!(done= smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout)))
+ goto RESPONSE_FAILED;
+
+ /* Not worth checking greeting line for ESMTP support */
+ if (!(esmtp = verify_check_this_host(&(ob->hosts_avoid_esmtp), NULL,
+ host->name, host->address, NULL) != OK))
+ DEBUG(D_transport)
+ debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
+
+ tls_redo_helo:
+
+ #ifdef SUPPORT_TLS
+ if (smtps && tls_out.active < 0) /* ssl-on-connect, first pass */
+ {
+ tls_offered = TRUE;
+ ob->tls_tempfail_tryclear = FALSE;
+ }
+ else /* all other cases */
+ #endif
+
+ { esmtp_retry:
+
+ if (!(done= smtp_write_command(&outblock, FALSE, "%s %s\r\n",
+ !esmtp? "HELO" : lmtp? "LHLO" : "EHLO", active_hostname) >= 0))
+ goto SEND_FAILED;
+ if (!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout))
+ {
+ if (errno != 0 || responsebuffer[0] == 0 || lmtp || !esmtp || tls_out.active >= 0)
+ {
+ done= FALSE;
+ goto RESPONSE_FAILED;
+ }
+ #ifdef SUPPORT_TLS
+ tls_offered = FALSE;
+ #endif
+ esmtp = FALSE;
+ goto esmtp_retry; /* fallback to HELO */
+ }
+
+ /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
+ #ifdef SUPPORT_TLS
+ tls_offered = esmtp && !suppress_tls && tls_out.active < 0 &&
+ pcre_exec(regex_STARTTLS, NULL, CS responsebuffer, Ustrlen(responsebuffer), 0,
+ PCRE_EOPT, NULL, 0) >= 0;
+ #endif
+ }
+
+ /* If TLS is available on this connection attempt to
+ start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
+ send another EHLO - the server may give a different answer in secure mode. We
+ use a separate buffer for reading the response to STARTTLS so that if it is
+ negative, the original EHLO data is available for subsequent analysis, should
+ the client not be required to use TLS. If the response is bad, copy the buffer
+ for error analysis. */
+
+ #ifdef SUPPORT_TLS
+ if (tls_offered &&
+ verify_check_this_host(&(ob->hosts_avoid_tls), NULL, host->name,
+ host->address, NULL) != OK)
+ {
+ uschar buffer2[4096];
+ if ( !smtps
+ && !(done= smtp_write_command(&outblock, FALSE, "STARTTLS\r\n") >= 0))
+ goto SEND_FAILED;
+
+ /* If there is an I/O error, transmission of this message is deferred. If
+ there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
+ false, we also defer. However, if there is a temporary rejection of STARTTLS
+ and tls_tempfail_tryclear is true, or if there is an outright rejection of
+ STARTTLS, we carry on. This means we will try to send the message in clear,
+ unless the host is in hosts_require_tls (tested below). */
+
+ if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
+ ob->command_timeout))
+ {
+ if (errno != 0 || buffer2[0] == 0 ||
+ (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
+ {
+ Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
+ done= FALSE;
+ goto RESPONSE_FAILED;
+ }
+ }
+
+ /* STARTTLS accepted or ssl-on-connect: try to negotiate a TLS session. */
+ else
+ {
+ int rc = tls_client_start(inblock.sock, host, addr,
+ NULL, /* No DH param */
+ ob->tls_certificate, ob->tls_privatekey,
+ ob->tls_sni,
+ ob->tls_verify_certificates, ob->tls_crl,
+ ob->tls_require_ciphers,
+ ob->gnutls_require_mac, ob->gnutls_require_kx, ob->gnutls_require_proto,
+ callout);
+
+ /* TLS negotiation failed; give an error. Try in clear on a new connection,
+ if the options permit it for this host. */
+ if (rc != OK)
+ {
+ if (rc == DEFER && ob->tls_tempfail_tryclear && !smtps &&
+ verify_check_this_host(&(ob->hosts_require_tls), NULL, host->name,
+ host->address, NULL) != OK)
+ {
+ (void)close(inblock.sock);
+ log_write(0, LOG_MAIN, "TLS session failure: delivering unencrypted "
+ "to %s [%s] (not in hosts_require_tls)", host->name, host->address);
+ suppress_tls = TRUE;
+ goto tls_retry_connection;
+ }
+ /*save_errno = ERRNO_TLSFAILURE;*/
+ /*message = US"failure while setting up TLS session";*/
+ send_quit = FALSE;
+ done= FALSE;
+ goto TLS_FAILED;
+ }
+
+ /* TLS session is set up. Copy info for logging. */
+ addr->cipher = tls_out.cipher;
+ addr->peerdn = tls_out.peerdn;
+
+ /* For SMTPS we need to wait for the initial OK response, then do HELO. */
+ if (smtps)
+ goto smtps_redo_greeting;
+
+ /* For STARTTLS we need to redo EHLO */
+ goto tls_redo_helo;
+ }
+ }
+
+ /* If the host is required to use a secure channel, ensure that we have one. */
+ if (tls_out.active < 0)
+ if (verify_check_this_host(&(ob->hosts_require_tls), NULL, host->name,
+ host->address, NULL) == OK)
+ {
+ /*save_errno = ERRNO_TLSREQUIRED;*/
+ log_write(0, LOG_MAIN, "a TLS session is required for %s [%s], but %s",
+ host->name, host->address,
+ tls_offered? "an attempt to start TLS failed" : "the server did not offer TLS support");
+ done= FALSE;
+ goto TLS_FAILED;
+ }
+
+ #endif /*SUPPORT_TLS*/
+
+ done = TRUE; /* so far so good; have response to HELO */
+
+ /*XXX the EHLO response would be analyzed here for IGNOREQUOTA, SIZE, PIPELINING, AUTH */
+ /* If we haven't authenticated, but are required to, give up. */
+
+ /*XXX "filter command specified for this transport" ??? */
+ /* for now, transport_filter by cutthrough-delivery is not supported */
+ /* Need proper integration with the proper transport mechanism. */
+
+
+ SEND_FAILED:
+ RESPONSE_FAILED:
+ TLS_FAILED:
+ ;
+ /* Clear down of the TLS, SMTP and TCP layers on error is handled below. */
+
git://git.exim.org / exim.git / commitdiff