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 do { \ 370 res = read_remote(fd, 0, NULL); \ 371 if (res == 5) { \ 372 syslog(LOG_ERR, "remote delivery to %s [%s] failed after %s: %s", \ 373 host->host, host->addr, c, neterr); \ 374 snprintf(errmsg, sizeof(errmsg), "%s [%s] did not like our %s:\n%s", \ 375 host->host, host->addr, c, neterr); \ 376 return (-1); \ 377 } else if (res != exp) { \ 378 syslog(LOG_NOTICE, "remote delivery deferred: %s [%s] failed after %s: %s", \ 379 host->host, host->addr, c, neterr); \ 380 return (1); \ 381 } \ 382 } while (0) 383 384 /* Check first reply from remote host */ 385 if ((config.features & SECURETRANS) == 0 || 386 (config.features & STARTTLS) != 0) { 387 config.features |= NOSSL; 388 READ_REMOTE_CHECK("connect", 2); 389 390 config.features &= ~NOSSL; 391 } 392 393 if ((config.features & SECURETRANS) != 0) { 394 error = smtp_init_crypto(fd, config.features); 395 if (error == 0) 396 syslog(LOG_DEBUG, "SSL initialization successful"); 397 else 398 goto out; 399 400 if ((config.features & STARTTLS) == 0) 401 READ_REMOTE_CHECK("connect", 2); 402 } 403 404 /* XXX allow HELO fallback */ 405 /* XXX record ESMTP keywords */ 406 send_remote_command(fd, "EHLO %s", hostname()); 407 READ_REMOTE_CHECK("EHLO", 2); 408 409 /* 410 * Use SMTP authentication if the user defined an entry for the remote 411 * or smarthost 412 */ 413 SLIST_FOREACH(a, &authusers, next) { 414 if (strcmp(a->host, host->host) == 0) { 415 do_auth = 1; 416 break; 417 } 418 } 419 420 if (do_auth == 1) { 421 /* 422 * Check if the user wants plain text login without using 423 * encryption. 424 */ 425 syslog(LOG_INFO, "using SMTP authentication for user %s", a->login); 426 error = smtp_login(fd, a->login, a->password); 427 if (error < 0) { 428 syslog(LOG_ERR, "remote delivery failed:" 429 " SMTP login failed: %m"); 430 snprintf(errmsg, sizeof(errmsg), "SMTP login to %s failed", host->host); 431 return (-1); 432 } 433 /* SMTP login is not available, so try without */ 434 else if (error > 0) { 435 syslog(LOG_WARNING, "SMTP login not available. Trying without."); 436 } 437 } 438 439 /* XXX send ESMTP ENVID, RET (FULL/HDRS) and 8BITMIME */ 440 send_remote_command(fd, "MAIL FROM:<%s>", it->sender); 441 READ_REMOTE_CHECK("MAIL FROM", 2); 442 443 /* XXX send ESMTP ORCPT */ 444 send_remote_command(fd, "RCPT TO:<%s>", it->addr); 445 READ_REMOTE_CHECK("RCPT TO", 2); 446 447 send_remote_command(fd, "DATA"); 448 READ_REMOTE_CHECK("DATA", 3); 449 450 error = 0; 451 while (!feof(it->mailf)) { 452 if (fgets(line, sizeof(line), it->mailf) == NULL) 453 break; 454 linelen = strlen(line); 455 if (linelen == 0 || line[linelen - 1] != '\n') { 456 syslog(LOG_CRIT, "remote delivery failed: corrupted queue file"); 457 snprintf(errmsg, sizeof(errmsg), "corrupted queue file"); 458 error = -1; 459 goto out; 460 } 461 462 /* Remove trailing \n's and escape leading dots */ 463 trim_line(line); 464 465 /* 466 * If the first character is a dot, we escape it so the line 467 * length increases 468 */ 469 if (line[0] == '.') 470 linelen++; 471 472 if (send_remote_command(fd, "%s", line) != (ssize_t)linelen+1) { 473 syslog(LOG_NOTICE, "remote delivery deferred: write error"); 474 error = 1; 475 goto out; 476 } 477 } 478 479 send_remote_command(fd, "."); 480 READ_REMOTE_CHECK("final DATA", 2); 481 482 send_remote_command(fd, "QUIT"); 483 if (read_remote(fd, 0, NULL) != 2) 484 syslog(LOG_INFO, "remote delivery succeeded but QUIT failed: %s", neterr); 485 out: 486 487 close_connection(fd); 488 return (error); 489 } 490 491 int 492 deliver_remote(struct qitem *it) 493 { 494 struct mx_hostentry *hosts, *h; 495 const char *host; 496 int port; 497 int error = 1, smarthost = 0; 498 499 port = SMTP_PORT; 500 501 /* Smarthost support? */ 502 if (config.smarthost != NULL) { 503 host = config.smarthost; 504 port = config.port; 505 syslog(LOG_INFO, "using smarthost (%s:%i)", host, port); 506 smarthost = 1; 507 } else { 508 host = strrchr(it->addr, '@'); 509 /* Should not happen */ 510 if (host == NULL) { 511 snprintf(errmsg, sizeof(errmsg), "Internal error: badly formed address %s", 512 it->addr); 513 return(-1); 514 } else { 515 /* Step over the @ */ 516 host++; 517 } 518 } 519 520 error = dns_get_mx_list(host, port, &hosts, smarthost); 521 if (error) { 522 snprintf(errmsg, sizeof(errmsg), "DNS lookup failure: host %s not found", host); 523 syslog(LOG_NOTICE, "remote delivery %s: DNS lookup failure: host %s not found", 524 error < 0 ? "failed" : "deferred", 525 host); 526 return (error); 527 } 528 529 for (h = hosts; *h->host != 0; h++) { 530 switch (deliver_to_host(it, h)) { 531 case 0: 532 /* success */ 533 error = 0; 534 goto out; 535 case 1: 536 /* temp failure */ 537 error = 1; 538 break; 539 default: 540 /* perm failure */ 541 error = -1; 542 goto out; 543 } 544 } 545 out: 546 free(hosts); 547 548 return (error); 549 } 550