src/common/smtp.c

   1 /*
   2  * Claws Mail -- a GTK based, lightweight, and fast e-mail client
   3  * Copyright (C) 1999-2022 the Claws Mail team and Hiroyuki Yamamoto
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  17  *
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #  include "config.h"
  22 #include "claws-features.h"
  23 #endif
  24
  25 #include <glib.h>
  26 #ifdef ENABLE_NLS
  27 #include <glib/gi18n.h>
  28 #else
  29 #define _(a) (a)
  30 #define N_(a) (a)
  31 #endif
  32 #include <stdio.h>
  33 #include <string.h>
  34
  35 #include "smtp.h"
  36 #include "md5.h"
  37 #include "utils.h"
  38 #include "log.h"
  39
  40 static void smtp_session_destroy(Session *session);
  41
  42 static gint smtp_auth(SMTPSession *session);
  43 #ifdef USE_GNUTLS
  44 static gint smtp_starttls(SMTPSession *session);
  45 #endif
  46 #ifdef USE_OAUTH2
  47 static gint smtp_auth_oauth2(SMTPSession *session);
  48 #endif
  49 static gint smtp_auth_cram_md5(SMTPSession *session);
  50 static gint smtp_auth_login(SMTPSession *session);
  51 static gint smtp_auth_plain(SMTPSession *session);
  52
  53 static gint smtp_ehlo(SMTPSession *session);
  54 static gint smtp_ehlo_recv(SMTPSession *session, const gchar *msg);
  55
  56 static gint smtp_helo(SMTPSession *session);
  57 static gint smtp_rcpt(SMTPSession *session);
  58 static gint smtp_data(SMTPSession *session);
  59 static gint smtp_send_data(SMTPSession *session);
  60 static gint smtp_make_ready(SMTPSession *session);
  61 static gint smtp_eom(SMTPSession *session);
  62
  63 static gint smtp_session_recv_msg(Session *session, const gchar *msg);
  64 static gint smtp_session_send_data_finished(Session *session, guint len);
  65
  66
  67 Session *smtp_session_new(void *prefs_account)
  68 {
  69         SMTPSession *session;
  70
  71         session = g_new0(SMTPSession, 1);
  72
  73         session_init(SESSION(session), prefs_account, TRUE);
  74
  75         SESSION(session)->type             = SESSION_SMTP;
  76
  77         SESSION(session)->recv_msg         = smtp_session_recv_msg;
  78
  79         SESSION(session)->recv_data_finished = NULL;
  80         SESSION(session)->send_data_finished = smtp_session_send_data_finished;
  81
  82         SESSION(session)->destroy          = smtp_session_destroy;
  83
  84         session->state                     = SMTP_READY;
  85
  86 #ifdef USE_GNUTLS
  87         session->tls_init_done             = FALSE;
  88 #endif
  89
  90         session->hostname                  = NULL;
  91         session->user                      = NULL;
  92         session->pass                      = NULL;
  93
  94         session->from                      = NULL;
  95         session->to_list                   = NULL;
  96         session->cur_to                    = NULL;
  97
  98         session->send_data                 = NULL;
  99         session->send_data_len             = 0;
 100
 101         session->avail_auth_type           = 0;
 102         session->forced_auth_type          = 0;
 103         session->auth_type                 = 0;
 104         session->esmtp_flags               = 0;
 105
 106         session->error_val                 = SM_OK;
 107         session->error_msg                 = NULL;
 108
 109         return SESSION(session);
 110 }
 111
 112 static void smtp_session_destroy(Session *session)
 113 {
 114         SMTPSession *smtp_session = SMTP_SESSION(session);
 115
 116         g_free(smtp_session->hostname);
 117         g_free(smtp_session->user);
 118         g_free(smtp_session->pass);
 119         g_free(smtp_session->from);
 120
 121         g_free(smtp_session->send_data);
 122
 123         g_free(smtp_session->error_msg);
 124 }
 125
 126 gint smtp_from(SMTPSession *session)
 127 {
 128         gchar buf[MESSAGEBUFSIZE];
 129         gchar *mail_size = NULL;
 130
 131         cm_return_val_if_fail(session->from != NULL, SM_ERROR);
 132
 133         session->state = SMTP_FROM;
 134
 135         if (session->is_esmtp && (session->esmtp_flags & ESMTP_SIZE)!=0)
 136                 mail_size = g_strdup_printf(" SIZE=%d", session->send_data_len);
 137         else
 138                 mail_size = g_strdup("");
 139
 140
 141         if (strchr(session->from, '<'))
 142                 g_snprintf(buf, sizeof(buf), "MAIL FROM:%s%s", session->from,
 143                            mail_size);
 144         else
 145                 g_snprintf(buf, sizeof(buf), "MAIL FROM:<%s>%s", session->from,
 146                            mail_size);
 147
 148         g_free(mail_size);
 149
 150         if (session_send_msg(SESSION(session), buf) < 0)
 151                 return SM_ERROR;
 152         log_print(LOG_PROTOCOL, "%sSMTP> %s\n", (session->is_esmtp?"E":""), buf);
 153
 154         return SM_OK;
 155 }
 156
 157 static gint smtp_auth(SMTPSession *session)
 158 {
 159
 160         cm_return_val_if_fail(session->user != NULL, SM_ERROR);
 161
 162         session->state = SMTP_AUTH;
 163
 164         if ((session->forced_auth_type == SMTPAUTH_CRAM_MD5
 165              || session->forced_auth_type == 0)
 166             &&
 167              (session->avail_auth_type & SMTPAUTH_CRAM_MD5) != 0)
 168                 smtp_auth_cram_md5(session);
 169         else if ((session->forced_auth_type == SMTPAUTH_LOGIN
 170                   || session->forced_auth_type == 0)
 171                  &&
 172                   (session->avail_auth_type & SMTPAUTH_LOGIN) != 0)
 173                 smtp_auth_login(session);
 174         else if ((session->forced_auth_type == SMTPAUTH_PLAIN
 175                   || session->forced_auth_type == 0)
 176                  &&
 177                   (session->avail_auth_type & SMTPAUTH_PLAIN) != 0)
 178                 smtp_auth_plain(session);
 179 #ifdef USE_OAUTH2
 180         else if ((session->forced_auth_type == SMTPAUTH_OAUTH2
 181                   || session->forced_auth_type == 0)
 182                  &&
 183                   (session->avail_auth_type & SMTPAUTH_OAUTH2) != 0)
 184                 smtp_auth_oauth2(session);
 185 #endif
 186         else if (session->forced_auth_type == 0) {
 187                 log_warning(LOG_PROTOCOL, _("No SMTP AUTH method available\n"));
 188                 return SM_AUTHFAIL;
 189         } else {
 190                 log_warning(LOG_PROTOCOL, _("Selected SMTP AUTH method not available\n"));
 191                 return SM_AUTHFAIL;
 192         }
 193
 194         return SM_OK;
 195 }
 196
 197 static gint smtp_auth_recv(SMTPSession *session, const gchar *msg)
 198 {
 199         gchar buf[MESSAGEBUFSIZE], *tmp;
 200
 201         switch (session->auth_type) {
 202         case SMTPAUTH_LOGIN:
 203                 session->state = SMTP_AUTH_LOGIN_USER;
 204
 205                 if (!strncmp(msg, "334 ", 4)) {
 206                         tmp = g_base64_encode(session->user, strlen(session->user));
 207
 208                         if (session_send_msg(SESSION(session), tmp) < 0) {
 209                                 g_free(tmp);
 210                                 return SM_ERROR;
 211                         }
 212                         g_free(tmp);
 213                         log_print(LOG_PROTOCOL, "ESMTP> [USERID]\n");
 214                 } else {
 215                         /* Server rejects AUTH */
 216                         if (session_send_msg(SESSION(session), "*") < 0)
 217                                 return SM_ERROR;
 218                         log_print(LOG_PROTOCOL, "ESMTP> *\n");
 219                 }
 220                 break;
 221         case SMTPAUTH_CRAM_MD5:
 222                 session->state = SMTP_AUTH_CRAM_MD5;
 223
 224                 if (!strncmp(msg, "334 ", 4)) {
 225                         gchar *response;
 226                         gchar *response64;
 227                         gchar *challenge;
 228                         gsize challengelen;
 229                         guchar hexdigest[33];
 230
 231                         challenge = g_base64_decode_zero(msg + 4, &challengelen);
 232                         log_print(LOG_PROTOCOL, "ESMTP< [Decoded: %s]\n", challenge);
 233
 234                         g_snprintf(buf, sizeof(buf), "%s", session->pass);
 235                         md5_hex_hmac(hexdigest, challenge, challengelen,
 236                                      buf, strlen(session->pass));
 237                         g_free(challenge);
 238
 239                         response = g_strdup_printf
 240                                 ("%s %s", session->user, hexdigest);
 241                         log_print(LOG_PROTOCOL, "ESMTP> [Encoded: %s]\n", response);
 242
 243                         response64 = g_base64_encode(response, strlen(response));
 244                         g_free(response);
 245
 246                         if (session_send_msg(SESSION(session), response64) < 0) {
 247                                 g_free(response64);
 248                                 return SM_ERROR;
 249                         }
 250                         log_print(LOG_PROTOCOL, "ESMTP> %s\n", response64);
 251                         g_free(response64);
 252                 } else {
 253                         /* Server rejects AUTH */
 254                         if (session_send_msg(SESSION(session), "*") < 0)
 255                                 return SM_ERROR;
 256                         log_print(LOG_PROTOCOL, "ESMTP> *\n");
 257                 }
 258                 break;
 259         case SMTPAUTH_DIGEST_MD5:
 260         default:
 261                 /* stop smtp_auth when no correct authtype */
 262                 if (session_send_msg(SESSION(session), "*") < 0)
 263                         return SM_ERROR;
 264                 log_print(LOG_PROTOCOL, "ESMTP> *\n");
 265                 break;
 266         }
 267
 268         return SM_OK;
 269 }
 270
 271 static gint smtp_auth_login_user_recv(SMTPSession *session, const gchar *msg)
 272 {
 273         gchar *tmp;
 274
 275         session->state = SMTP_AUTH_LOGIN_PASS;
 276
 277         if (!strncmp(msg, "334 ", 4)) {
 278                 tmp = g_base64_encode(session->pass, strlen(session->pass));
 279         } else {
 280                 /* Server rejects AUTH */
 281                 tmp = g_strdup("*");
 282         }
 283
 284         if (session_send_msg(SESSION(session), tmp) < 0) {
 285                 g_free(tmp);
 286                 return SM_ERROR;
 287         }
 288         g_free(tmp);
 289
 290         log_print(LOG_PROTOCOL, "ESMTP> [PASSWORD]\n");
 291
 292         return SM_OK;
 293 }
 294
 295 static gint smtp_ehlo(SMTPSession *session)
 296 {
 297         gchar buf[MESSAGEBUFSIZE];
 298
 299         session->state = SMTP_EHLO;
 300
 301         session->avail_auth_type = 0;
 302
 303         g_snprintf(buf, sizeof(buf), "EHLO %s",
 304                    session->hostname ? session->hostname : get_domain_name());
 305         if (session_send_msg(SESSION(session), buf) < 0)
 306                 return SM_ERROR;
 307         log_print(LOG_PROTOCOL, "ESMTP> %s\n", buf);
 308
 309         return SM_OK;
 310 }
 311
 312 static gint smtp_ehlo_recv(SMTPSession *session, const gchar *msg)
 313 {
 314         if (strncmp(msg, "250", 3) == 0) {
 315                 const gchar *p = msg;
 316                 p += 3;
 317                 if (*p == '-' || *p == ' ') p++;
 318                 if (g_ascii_strncasecmp(p, "AUTH", 4) == 0) {
 319                         p += 5;
 320                         if (strcasestr(p, "PLAIN"))
 321                                 session->avail_auth_type |= SMTPAUTH_PLAIN;
 322                         if (strcasestr(p, "LOGIN"))
 323                                 session->avail_auth_type |= SMTPAUTH_LOGIN;
 324                         if (strcasestr(p, "CRAM-MD5"))
 325                                 session->avail_auth_type |= SMTPAUTH_CRAM_MD5;
 326                         if (strcasestr(p, "DIGEST-MD5"))
 327                                 session->avail_auth_type |= SMTPAUTH_DIGEST_MD5;
 328 #ifdef USE_GNUTLS
 329                         if (strcasestr(p, "XOAUTH2"))
 330                                 session->avail_auth_type |= SMTPAUTH_OAUTH2;
 331 #endif
 332                 }
 333                 if (g_ascii_strncasecmp(p, "SIZE", 4) == 0) {
 334                         p += 5;
 335                         session->max_message_size = atoi(p);
 336                         session->esmtp_flags |= ESMTP_SIZE;
 337                 }
 338                 if (g_ascii_strncasecmp(p, "STARTTLS", 8) == 0) {
 339                         p += 9;
 340                         session->avail_auth_type |= SMTPAUTH_TLS_AVAILABLE;
 341                 }
 342                 return SM_OK;
 343         } else if ((msg[0] == '1' || msg[0] == '2' || msg[0] == '3') &&
 344             (msg[3] == ' ' || msg[3] == '\0'))
 345                 return SM_OK;
 346         else if (msg[0] == '5' && msg[1] == '0' &&
 347                  (msg[2] == '4' || msg[2] == '3' || msg[2] == '1'))
 348                 return SM_ERROR;
 349
 350         return SM_ERROR;
 351 }
 352
 353 #ifdef USE_GNUTLS
 354 static gint smtp_starttls(SMTPSession *session)
 355 {
 356         session->state = SMTP_STARTTLS;
 357
 358         if (session_send_msg(SESSION(session), "STARTTLS") < 0)
 359                 return SM_ERROR;
 360         log_print(LOG_PROTOCOL, "ESMTP> STARTTLS\n");
 361
 362         return SM_OK;
 363 }
 364 #endif
 365
 366 static gint smtp_auth_cram_md5(SMTPSession *session)
 367 {
 368         session->state = SMTP_AUTH;
 369         session->auth_type = SMTPAUTH_CRAM_MD5;
 370
 371         if (session_send_msg(SESSION(session), "AUTH CRAM-MD5") < 0)
 372                 return SM_ERROR;
 373         log_print(LOG_PROTOCOL, "ESMTP> AUTH CRAM-MD5\n");
 374
 375         return SM_OK;
 376 }
 377
 378 static gint smtp_auth_plain(SMTPSession *session)
 379 {
 380         gchar buf[MESSAGEBUFSIZE], *b64buf, *out;
 381         gint len;
 382
 383         session->state = SMTP_AUTH_PLAIN;
 384         session->auth_type = SMTPAUTH_PLAIN;
 385
 386         memset(buf, 0, sizeof buf);
 387
 388         /* "\0user\0password" */
 389         len = sprintf(buf, "%c%s%c%s", '\0', session->user, '\0', session->pass);
 390         b64buf = g_base64_encode(buf, len);
 391         out = g_strconcat("AUTH PLAIN ", b64buf, NULL);
 392         g_free(b64buf);
 393
 394         if (session_send_msg(SESSION(session), out) < 0) {
 395                 g_free(out);
 396                 return SM_ERROR;
 397         }
 398
 399         g_free(out);
 400
 401         log_print(LOG_PROTOCOL, "ESMTP> [AUTH PLAIN]\n");
 402
 403         return SM_OK;
 404 }
 405
 406 #ifdef USE_OAUTH2
 407 static gint smtp_auth_oauth2(SMTPSession *session)
 408 {
 409         gchar buf[MESSAGEBUFSIZE], *b64buf, *out;
 410         gint len;
 411
 412         session->state = SMTP_AUTH_OAUTH2;
 413         session->auth_type = SMTPAUTH_OAUTH2;
 414
 415         memset(buf, 0, sizeof buf);
 416
 417         /* "user=" {User} "^Aauth=Bearer " {Access Token} "^A^A"*/
 418         /* session->pass contains the OAUTH2 Access Token*/
 419         len = sprintf(buf, "user=%s\1auth=Bearer %s\1\1", session->user, session->pass);
 420         b64buf = g_base64_encode(buf, len);
 421         out = g_strconcat("AUTH XOAUTH2 ", b64buf, NULL);
 422         g_free(b64buf);
 423
 424         if (session_send_msg(SESSION(session), out) < 0) {
 425                 g_free(out);
 426                 return SM_ERROR;
 427         }
 428
 429         g_free(out);
 430
 431         log_print(LOG_PROTOCOL, "ESMTP> [AUTH XOAUTH2]\n");
 432
 433         return SM_OK;
 434 }
 435 #endif
 436
 437 static gint smtp_auth_login(SMTPSession *session)
 438 {
 439         session->state = SMTP_AUTH;
 440         session->auth_type = SMTPAUTH_LOGIN;
 441
 442         if (session_send_msg(SESSION(session), "AUTH LOGIN") < 0)
 443                 return SM_ERROR;
 444         log_print(LOG_PROTOCOL, "ESMTP> AUTH LOGIN\n");
 445
 446         return SM_OK;
 447 }
 448
 449 static gint smtp_helo(SMTPSession *session)
 450 {
 451         gchar buf[MESSAGEBUFSIZE];
 452
 453         session->state = SMTP_HELO;
 454
 455         g_snprintf(buf, sizeof(buf), "HELO %s",
 456                    session->hostname ? session->hostname : get_domain_name());
 457         if (session_send_msg(SESSION(session), buf) < 0)
 458                 return SM_ERROR;
 459         log_print(LOG_PROTOCOL, "SMTP> %s\n", buf);
 460
 461         return SM_OK;
 462 }
 463
 464 static gint smtp_rcpt(SMTPSession *session)
 465 {
 466         gchar buf[MESSAGEBUFSIZE];
 467         gchar *to;
 468
 469         cm_return_val_if_fail(session->cur_to != NULL, SM_ERROR);
 470
 471         session->state = SMTP_RCPT;
 472
 473         to = (gchar *)session->cur_to->data;
 474
 475         if (strchr(to, '<'))
 476                 g_snprintf(buf, sizeof(buf), "RCPT TO:%s", to);
 477         else
 478                 g_snprintf(buf, sizeof(buf), "RCPT TO:<%s>", to);
 479         if (session_send_msg(SESSION(session), buf) < 0)
 480                 return SM_ERROR;
 481         log_print(LOG_PROTOCOL, "SMTP> %s\n", buf);
 482
 483         session->cur_to = session->cur_to->next;
 484
 485         return SM_OK;
 486 }
 487
 488 static gint smtp_data(SMTPSession *session)
 489 {
 490         session->state = SMTP_DATA;
 491
 492         if (session_send_msg(SESSION(session), "DATA") < 0)
 493                 return SM_ERROR;
 494         log_print(LOG_PROTOCOL, "SMTP> DATA\n");
 495
 496         return SM_OK;
 497 }
 498
 499 static gint smtp_send_data(SMTPSession *session)
 500 {
 501         session->state = SMTP_SEND_DATA;
 502
 503         session_send_data(SESSION(session), session->send_data,
 504                           session->send_data_len);
 505
 506         return SM_OK;
 507 }
 508
 509 static gint smtp_make_ready(SMTPSession *session)
 510 {
 511         session->state = SMTP_MAIL_SENT_OK;
 512
 513         return SM_OK;
 514 }
 515
 516 gint smtp_quit(SMTPSession *session)
 517 {
 518         session->state = SMTP_QUIT;
 519
 520         session_send_msg(SESSION(session), "QUIT");
 521         log_print(LOG_PROTOCOL, "SMTP> QUIT\n");
 522
 523         return SM_OK;
 524 }
 525
 526 static gint smtp_eom(SMTPSession *session)
 527 {
 528         session->state = SMTP_EOM;
 529
 530         if (session_send_msg(SESSION(session), ".") < 0)
 531                 return SM_ERROR;
 532         log_print(LOG_PROTOCOL, "SMTP> . (EOM)\n");
 533
 534         return SM_OK;
 535 }
 536
 537 static gint smtp_session_recv_msg(Session *session, const gchar *msg)
 538 {
 539         SMTPSession *smtp_session = SMTP_SESSION(session);
 540         gboolean cont = FALSE;
 541         gint ret = 0;
 542
 543         if (strlen(msg) < 4) {
 544                 log_warning(LOG_PROTOCOL, _("bad SMTP response\n"));
 545                 return -1;
 546         }
 547
 548         switch (smtp_session->state) {
 549         case SMTP_EHLO:
 550         case SMTP_STARTTLS:
 551         case SMTP_AUTH:
 552         case SMTP_AUTH_PLAIN:
 553         case SMTP_AUTH_LOGIN_USER:
 554         case SMTP_AUTH_LOGIN_PASS:
 555 #ifdef USE_GNUTLS
 556         case SMTP_AUTH_OAUTH2:
 557 #endif
 558         case SMTP_AUTH_CRAM_MD5:
 559                 log_print(LOG_PROTOCOL, "ESMTP< %s\n", msg);
 560                 break;
 561         default:
 562                 log_print(LOG_PROTOCOL, "SMTP< %s\n", msg);
 563                 break;
 564         }
 565
 566         /* ignore all multiline responses except for EHLO */
 567         if (msg[3] == '-' && smtp_session->state != SMTP_EHLO)
 568                 return session_recv_msg(session);
 569
 570         if (msg[0] == '5' && msg[1] == '0' &&
 571             (msg[2] == '4' || msg[2] == '3' || msg[2] == '1')) {
 572                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 573                 smtp_session->state = SMTP_ERROR;
 574                 smtp_session->error_val = SM_ERROR;
 575                 g_free(smtp_session->error_msg);
 576                 smtp_session->error_msg = g_strdup(msg);
 577                 return -1;
 578         }
 579
 580         if (!strncmp(msg, "535", 3)) {
 581                 log_warning(LOG_PROTOCOL, _("error occurred on authentication\n"));
 582                 smtp_session->state = SMTP_ERROR;
 583                 smtp_session->error_val = SM_AUTHFAIL;
 584                 g_free(smtp_session->error_msg);
 585                 smtp_session->error_msg = g_strdup(msg);
 586                 return -1;
 587         }
 588
 589         if (msg[0] != '1' && msg[0] != '2' && msg[0] != '3') {
 590                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 591                 smtp_session->state = SMTP_ERROR;
 592                 smtp_session->error_val = SM_ERROR;
 593                 g_free(smtp_session->error_msg);
 594                 smtp_session->error_msg = g_strdup(msg);
 595                 return -1;
 596         }
 597
 598         if (msg[3] == '-')
 599                 cont = TRUE;
 600         else if (msg[3] != ' ' && msg[3] != '\0') {
 601                 log_warning(LOG_PROTOCOL, _("bad SMTP response\n"));
 602                 smtp_session->state = SMTP_ERROR;
 603                 smtp_session->error_val = SM_UNRECOVERABLE;
 604                 return -1;
 605         }
 606
 607         switch (smtp_session->state) {
 608         case SMTP_READY:
 609                 if (strstr(msg, "ESMTP"))
 610                         smtp_session->is_esmtp = TRUE;
 611 #ifdef USE_GNUTLS
 612                 if (smtp_session->user || session->ssl_type != SSL_NONE ||
 613                     smtp_session->is_esmtp)
 614 #else
 615                 if (smtp_session->user || smtp_session->is_esmtp)
 616 #endif
 617                         ret = smtp_ehlo(smtp_session);
 618                 else
 619                         ret = smtp_helo(smtp_session);
 620                 break;
 621         case SMTP_HELO:
 622                 ret = smtp_from(smtp_session);
 623                 break;
 624         case SMTP_EHLO:
 625                 ret = smtp_ehlo_recv(smtp_session, msg);
 626                 if (cont == TRUE)
 627                         break;
 628                 if (smtp_session->max_message_size > 0
 629                 && smtp_session->max_message_size <
 630                    smtp_session->send_data_len) {
 631                         log_warning(LOG_PROTOCOL, _("Message is too big "
 632                               "(Maximum size is %s)\n"),
 633                               to_human_readable(
 634                                (goffset)(smtp_session->max_message_size)));
 635                         smtp_session->state = SMTP_ERROR;
 636                         smtp_session->error_val = SM_ERROR;
 637                         return -1;
 638                 }
 639 #ifdef USE_GNUTLS
 640                 if (session->ssl_type == SSL_STARTTLS &&
 641                     smtp_session->tls_init_done == FALSE) {
 642                         ret = smtp_starttls(smtp_session);
 643                         break;
 644                 }
 645 #endif
 646                 if (smtp_session->user) {
 647                         if (smtp_auth(smtp_session) != SM_OK) {
 648 #ifdef USE_GNUTLS
 649                                 if (session->ssl_type == SSL_NONE
 650                                 &&  smtp_session->tls_init_done == FALSE
 651                                 &&  (smtp_session->avail_auth_type & SMTPAUTH_TLS_AVAILABLE))
 652                                         ret = smtp_starttls(smtp_session);
 653                                 else
 654 #endif
 655                                         ret = smtp_from(smtp_session);
 656                         }
 657                 } else
 658                         ret = smtp_from(smtp_session);
 659                 break;
 660         case SMTP_STARTTLS:
 661 #ifdef USE_GNUTLS
 662                 if (session_start_tls(session) < 0) {
 663                         log_warning(LOG_PROTOCOL, _("couldn't start STARTTLS session\n"));
 664                         smtp_session->state = SMTP_ERROR;
 665                         smtp_session->error_val = SM_ERROR;
 666                         return -1;
 667                 }
 668                 smtp_session->tls_init_done = TRUE;
 669                 ret = smtp_ehlo(smtp_session);
 670 #endif
 671                 break;
 672         case SMTP_AUTH:
 673                 ret = smtp_auth_recv(smtp_session, msg);
 674                 break;
 675         case SMTP_AUTH_LOGIN_USER:
 676                 ret = smtp_auth_login_user_recv(smtp_session, msg);
 677                 break;
 678         case SMTP_AUTH_PLAIN:
 679         case SMTP_AUTH_LOGIN_PASS:
 680 #ifdef USE_GNUTLS
 681         case SMTP_AUTH_OAUTH2:
 682 #endif
 683         case SMTP_AUTH_CRAM_MD5:
 684                 ret = smtp_from(smtp_session);
 685                 break;
 686         case SMTP_FROM:
 687                 if (smtp_session->cur_to)
 688                         ret = smtp_rcpt(smtp_session);
 689                 break;
 690         case SMTP_RCPT:
 691                 if (smtp_session->cur_to)
 692                         ret = smtp_rcpt(smtp_session);
 693                 else
 694                         ret = smtp_data(smtp_session);
 695                 break;
 696         case SMTP_DATA:
 697                 ret = smtp_send_data(smtp_session);
 698                 break;
 699         case SMTP_EOM:
 700                 smtp_make_ready(smtp_session);
 701                 break;
 702         case SMTP_QUIT:
 703                 session_disconnect(session);
 704                 break;
 705         case SMTP_ERROR:
 706         default:
 707                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 708                 smtp_session->error_val = SM_ERROR;
 709                 return -1;
 710         }
 711
 712         if (cont && ret == SM_OK)
 713                 return session_recv_msg(session);
 714
 715         if (ret != SM_OK)
 716                 smtp_session->error_val = SM_ERROR;
 717
 718         return ret == SM_OK ? 0 : -1;
 719 }
 720
 721 static gint smtp_session_send_data_finished(Session *session, guint len)
 722 {
 723         return smtp_eom(SMTP_SESSION(session));
 724 }