1 /* 2 * Copyright (c) 2008-2014, Simon Schubert <2@0x2c.org>. 3 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Matthias Schmidt <matthias@dragonflybsd.org>, University of Marburg, 7 * Germany. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in 17 * the documentation and/or other materials provided with the 18 * distribution. 19 * 3. Neither the name of The DragonFly Project nor the names of its 20 * contributors may be used to endorse or promote products derived 21 * from this software without specific, prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 26 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 27 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 29 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 30 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 31 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 32 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 33 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include "dfcompat.h" 38 39 #include <sys/param.h> 40 #include <sys/queue.h> 41 #include <sys/stat.h> 42 #include <sys/types.h> 43 #include <sys/socket.h> 44 #include <netinet/in.h> 45 #include <arpa/inet.h> 46 47 #include <openssl/ssl.h> 48 #include <openssl/err.h> 49 50 #include <ctype.h> 51 #include <err.h> 52 #include <errno.h> 53 #include <netdb.h> 54 #include <setjmp.h> 55 #include <signal.h> 56 #include <syslog.h> 57 #include <unistd.h> 58 59 #include "dma.h" 60 61 char neterr[ERRMSG_SIZE]; 62 63 char * 64 ssl_errstr(void) 65 { 66 long oerr, nerr; 67 68 oerr = 0; 69 while ((nerr = ERR_get_error()) != 0) 70 oerr = nerr; 71 72 return (ERR_error_string(oerr, NULL)); 73 } 74 75 ssize_t 76 send_remote_command(int fd, const char* fmt, ...) 77 { 78 va_list va; 79 char cmd[4096]; 80 size_t len, pos; 81 int s; 82 ssize_t n; 83 84 va_start(va, fmt); 85 s = vsnprintf(cmd, sizeof(cmd) - 2, fmt, va); 86 va_end(va); 87 if (s == sizeof(cmd) - 2 || s < 0) { 88 strcpy(neterr, "Internal error: oversized command string"); 89 return (-1); 90 } 91 92 /* We *know* there are at least two more bytes available */ 93 strcat(cmd, "\r\n"); 94 len = strlen(cmd); 95 96 if (((config.features & SECURETRANS) != 0) && 97 ((config.features & NOSSL) == 0)) { 98 while ((s = SSL_write(config.ssl, (const char*)cmd, len)) <= 0) { 99 s = SSL_get_error(config.ssl, s); 100 if (s != SSL_ERROR_WANT_READ && 101 s != SSL_ERROR_WANT_WRITE) { 102 strncpy(neterr, ssl_errstr(), sizeof(neterr)); 103 return (-1); 104 } 105 } 106 } 107 else { 108 pos = 0; 109 while (pos < len) { 110 n = write(fd, cmd + pos, len - pos); 111 if (n < 0) 112 return (-1); 113 pos += n; 114 } 115 } 116 117 return (len); 118 } 119 120 int 121 read_remote(int fd, int extbufsize, char *extbuf) 122 { 123 ssize_t rlen = 0; 124 size_t pos, len, copysize; 125 char buff[BUF_SIZE]; 126 int done = 0, status = 0, status_running = 0, extbufpos = 0; 127 enum { parse_status, parse_spacedash, parse_rest } parsestate; 128 129 if (do_timeout(CON_TIMEOUT, 1) != 0) { 130 snprintf(neterr, sizeof(neterr), "Timeout reached"); 131 return (-1); 132 } 133 134 /* 135 * Remote reading code from femail.c written by Henning Brauer of 136 * OpenBSD and released under a BSD style license. 137 */ 138 len = 0; 139 pos = 0; 140 parsestate = parse_status; 141 neterr[0] = 0; 142 while (!(done && parsestate == parse_status)) { 143 rlen = 0; 144 if (pos == 0 || 145 (pos > 0 && memchr(buff + pos, '\n', len - pos) == NULL)) { 146 memmove(buff, buff + pos, len - pos); 147 len -= pos; 148 pos = 0; 149 if (((config.features & SECURETRANS) != 0) && 150 (config.features & NOSSL) == 0) { 151 if ((rlen = SSL_read(config.ssl, buff + len, sizeof(buff) - len)) == -1) { 152 strncpy(neterr, ssl_errstr(), sizeof(neterr)); 153 goto error; 154 } 155 } else { 156 if ((rlen = read(fd, buff + len, sizeof(buff) - len)) == -1) { 157 strncpy(neterr, strerror(errno), sizeof(neterr)); 158 goto error; 159 } 160 } 161 len += rlen; 162 163 copysize = sizeof(neterr) - strlen(neterr) - 1; 164 if (copysize > len) 165 copysize = len; 166 strncat(neterr, buff, copysize); 167 } 168 /* 169 * If there is an external buffer with a size bigger than zero 170 * and as long as there is space in the external buffer and 171 * there are new characters read from the mailserver 172 * copy them to the external buffer 173 */ 174 if (extbufpos <= (extbufsize - 1) && rlen > 0 && extbufsize > 0 && extbuf != NULL) { 175 /* do not write over the bounds of the buffer */ 176 if(extbufpos + rlen > (extbufsize - 1)) { 177 rlen = extbufsize - extbufpos; 178 } 179 memcpy(extbuf + extbufpos, buff + len - rlen, rlen); 180 extbufpos += rlen; 181 } 182 183 if (pos == len) 184 continue; 185 186 switch (parsestate) { 187 case parse_status: 188 for (; pos < len; pos++) { 189 if (isdigit(buff[pos])) { 190 status_running = status_running * 10 + (buff[pos] - '0'); 191 } else { 192 status = status_running; 193 status_running = 0; 194 parsestate = parse_spacedash; 195 break; 196 } 197 } 198 continue; 199 200 case parse_spacedash: 201 switch (buff[pos]) { 202 case ' ': 203 done = 1; 204 break; 205 206 case '-': 207 /* ignore */ 208 /* XXX read capabilities */ 209 break; 210 211 default: 212 strcpy(neterr, "invalid syntax in reply from server"); 213 goto error; 214 } 215 216 pos++; 217 parsestate = parse_rest; 218 continue; 219 220 case parse_rest: 221 /* skip up to \n */ 222 for (; pos < len; pos++) { 223 if (buff[pos] == '\n') { 224 pos++; 225 parsestate = parse_status; 226 break; 227 } 228 } 229 } 230 231 } 232 233 do_timeout(0, 0); 234 235 /* chop off trailing newlines */ 236 while (neterr[0] != 0 && strchr("\r\n", neterr[strlen(neterr) - 1]) != 0) 237 neterr[strlen(neterr) - 1] = 0; 238 239 return (status/100); 240 241 error: 242 do_timeout(0, 0); 243 return (-1); 244 } 245 246 /* 247 * Handle SMTP authentication 248 */ 249 static int 250 smtp_login(int fd, char *login, char* password) 251 { 252 char *temp; 253 int len, res = 0; 254 255 res = smtp_auth_md5(fd, login, password); 256 if (res == 0) { 257 return (0); 258 } else if (res == -2) { 259 /* 260 * If the return code is -2, then then the login attempt failed, 261 * do not try other login mechanisms 262 */ 263 return (1); 264 } 265 266 if ((config.features & INSECURE) != 0 || 267 (config.features & SECURETRANS) != 0) { 268 /* Send AUTH command according to RFC 2554 */ 269 send_remote_command(fd, "AUTH LOGIN"); 270 if (read_remote(fd, 0, NULL) != 3) { 271 syslog(LOG_NOTICE, "remote delivery deferred:" 272 " AUTH login not available: %s", 273 neterr); 274 return (1); 275 } 276 277 len = base64_encode(login, strlen(login), &temp); 278 if (len < 0) { 279 encerr: 280 syslog(LOG_ERR, "can not encode auth reply: %m"); 281 return (1); 282 } 283 284 send_remote_command(fd, "%s", temp); 285 free(temp); 286 res = read_remote(fd, 0, NULL); 287 if (res != 3) { 288 syslog(LOG_NOTICE, "remote delivery %s: AUTH login failed: %s", 289 res == 5 ? "failed" : "deferred", neterr); 290 return (res == 5 ? -1 : 1); 291 } 292 293 len = base64_encode(password, strlen(password), &temp); 294 if (len < 0) 295 goto encerr; 296 297 send_remote_command(fd, "%s", temp); 298 free(temp); 299 res = read_remote(fd, 0, NULL); 300 if (res != 2) { 301 syslog(LOG_NOTICE, "remote delivery %s: Authentication failed: %s", 302 res == 5 ? "failed" : "deferred", neterr); 303 return (res == 5 ? -1 : 1); 304 } 305 } else { 306 syslog(LOG_WARNING, "non-encrypted SMTP login is disabled in config, so skipping it. "); 307 return (1); 308 } 309 310 return (0); 311 } 312 313 static int 314 open_connection(struct mx_hostentry *h) 315 { 316 int fd; 317 318 syslog(LOG_INFO, "trying remote delivery to %s [%s] pref %d", 319 h->host, h->addr, h->pref); 320 321 fd = socket(h->ai.ai_family, h->ai.ai_socktype, h->ai.ai_protocol); 322 if (fd < 0) { 323 syslog(LOG_INFO, "socket for %s [%s] failed: %m", 324 h->host, h->addr); 325 return (-1); 326 } 327 328 if (connect(fd, (struct sockaddr *)&h->sa, h->ai.ai_addrlen) < 0) { 329 syslog(LOG_INFO, "connect to %s [%s] failed: %m", 330 h->host, h->addr); 331 close(fd); 332 return (-1); 333 } 334 335 return (fd); 336 } 337 338 static void 339 close_connection(int fd) 340 { 341 if (config.ssl != NULL) { 342 if (((config.features & SECURETRANS) != 0) && 343 ((config.features & NOSSL) == 0)) 344 SSL_shutdown(config.ssl); 345 SSL_free(config.ssl); 346 } 347 348 close(fd); 349 } 350 351 static int 352 deliver_to_host(struct qitem *it, struct mx_hostentry *host) 353 { 354 struct authuser *a; 355 char line[1000]; 356 size_t linelen; 357 int fd, error = 0, do_auth = 0, res = 0; 358 359 if (fseek(it->mailf, 0, SEEK_SET) != 0) { 360 snprintf(errmsg, sizeof(errmsg), "can not seek: %s", strerror(errno)); 361 return (-1); 362 } 363 364 fd = open_connection(host); 365 if (fd < 0) 366 return (1); 367 368 #define READ_REMOTE_CHECK(c, exp) \ 369 res = read_remote(fd, 0, NULL); \ 370 if (res == 5) { \ 371 syslog(LOG_ERR, "remote delivery to %s [%s] failed after %s: %s", \ 372 host->host, host->addr, c, neterr); \ 373 snprintf(errmsg, sizeof(errmsg), "%s [%s] did not like our %s:\n%s", \ 374 host->host, host->addr, c, neterr); \ 375 return (-1); \ 376 } else if (res != exp) { \ 377 syslog(LOG_NOTICE, "remote delivery deferred: %s [%s] failed after %s: %s", \ 378 host->host, host->addr, c, neterr); \ 379 return (1); \ 380 } 381 382 /* Check first reply from remote host */ 383 if ((config.features & SECURETRANS) == 0 || 384 (config.features & STARTTLS) != 0) { 385 config.features |= NOSSL; 386 READ_REMOTE_CHECK("connect", 2); 387 388 config.features &= ~NOSSL; 389 } 390 391 if ((config.features & SECURETRANS) != 0) { 392 error = smtp_init_crypto(fd, config.features); 393 if (error == 0) 394 syslog(LOG_DEBUG, "SSL initialization successful"); 395 else 396 goto out; 397 398 if ((config.features & STARTTLS) == 0) 399 READ_REMOTE_CHECK("connect", 2); 400 } 401 402 /* XXX allow HELO fallback */ 403 /* XXX record ESMTP keywords */ 404 send_remote_command(fd, "EHLO %s", hostname()); 405 READ_REMOTE_CHECK("EHLO", 2); 406 407 /* 408 * Use SMTP authentication if the user defined an entry for the remote 409 * or smarthost 410 */ 411 SLIST_FOREACH(a, &authusers, next) { 412 if (strcmp(a->host, host->host) == 0) { 413 do_auth = 1; 414 break; 415 } 416 } 417 418 if (do_auth == 1) { 419 /* 420 * Check if the user wants plain text login without using 421 * encryption. 422 */ 423 syslog(LOG_INFO, "using SMTP authentication for user %s", a->login); 424 error = smtp_login(fd, a->login, a->password); 425 if (error < 0) { 426 syslog(LOG_ERR, "remote delivery failed:" 427 " SMTP login failed: %m"); 428 snprintf(errmsg, sizeof(errmsg), "SMTP login to %s failed", host->host); 429 return (-1); 430 } 431 /* SMTP login is not available, so try without */ 432 else if (error > 0) { 433 syslog(LOG_WARNING, "SMTP login not available. Trying without."); 434 } 435 } 436 437 /* XXX send ESMTP ENVID, RET (FULL/HDRS) and 8BITMIME */ 438 send_remote_command(fd, "MAIL FROM:<%s>", it->sender); 439 READ_REMOTE_CHECK("MAIL FROM", 2); 440 441 /* XXX send ESMTP ORCPT */ 442 send_remote_command(fd, "RCPT TO:<%s>", it->addr); 443 READ_REMOTE_CHECK("RCPT TO", 2); 444 445 send_remote_command(fd, "DATA"); 446 READ_REMOTE_CHECK("DATA", 3); 447 448 error = 0; 449 while (!feof(it->mailf)) { 450 if (fgets(line, sizeof(line), it->mailf) == NULL) 451 break; 452 linelen = strlen(line); 453 if (linelen == 0 || line[linelen - 1] != '\n') { 454 syslog(LOG_CRIT, "remote delivery failed: corrupted queue file"); 455 snprintf(errmsg, sizeof(errmsg), "corrupted queue file"); 456 error = -1; 457 goto out; 458 } 459 460 /* Remove trailing \n's and escape leading dots */ 461 trim_line(line); 462 463 /* 464 * If the first character is a dot, we escape it so the line 465 * length increases 466 */ 467 if (line[0] == '.') 468 linelen++; 469 470 if (send_remote_command(fd, "%s", line) != (ssize_t)linelen+1) { 471 syslog(LOG_NOTICE, "remote delivery deferred: write error"); 472 error = 1; 473 goto out; 474 } 475 } 476 477 send_remote_command(fd, "."); 478 READ_REMOTE_CHECK("final DATA", 2); 479 480 send_remote_command(fd, "QUIT"); 481 if (read_remote(fd, 0, NULL) != 2) 482 syslog(LOG_INFO, "remote delivery succeeded but QUIT failed: %s", neterr); 483 out: 484 485 close_connection(fd); 486 return (error); 487 } 488 489 int 490 deliver_remote(struct qitem *it) 491 { 492 struct mx_hostentry *hosts, *h; 493 const char *host; 494 int port; 495 int error = 1, smarthost = 0; 496 497 port = SMTP_PORT; 498 499 /* Smarthost support? */ 500 if (config.smarthost != NULL) { 501 host = config.smarthost; 502 port = config.port; 503 syslog(LOG_INFO, "using smarthost (%s:%i)", host, port); 504 smarthost = 1; 505 } else { 506 host = strrchr(it->addr, '@'); 507 /* Should not happen */ 508 if (host == NULL) { 509 snprintf(errmsg, sizeof(errmsg), "Internal error: badly formed address %s", 510 it->addr); 511 return(-1); 512 } else { 513 /* Step over the @ */ 514 host++; 515 } 516 } 517 518 error = dns_get_mx_list(host, port, &hosts, smarthost); 519 if (error) { 520 snprintf(errmsg, sizeof(errmsg), "DNS lookup failure: host %s not found", host); 521 syslog(LOG_NOTICE, "remote delivery %s: DNS lookup failure: host %s not found", 522 error < 0 ? "failed" : "deferred", 523 host); 524 return (error); 525 } 526 527 for (h = hosts; *h->host != 0; h++) { 528 switch (deliver_to_host(it, h)) { 529 case 0: 530 /* success */ 531 error = 0; 532 goto out; 533 case 1: 534 /* temp failure */ 535 error = 1; 536 break; 537 default: 538 /* perm failure */ 539 error = -1; 540 goto out; 541 } 542 } 543 out: 544 free(hosts); 545 546 return (error); 547 } 548