1 /* 2 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthias Schmidt <matthias@dragonflybsd.org>, University of Marburg, 6 * Germany. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in 16 * the documentation and/or other materials provided with the 17 * distribution. 18 * 3. Neither the name of The DragonFly Project nor the names of its 19 * contributors may be used to endorse or promote products derived 20 * from this software without specific, prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 26 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 28 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 30 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 31 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 32 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/param.h> 37 #include <sys/queue.h> 38 #include <sys/stat.h> 39 #include <sys/types.h> 40 #include <sys/socket.h> 41 #include <netinet/in.h> 42 #include <arpa/inet.h> 43 44 #include <openssl/ssl.h> 45 #include <openssl/err.h> 46 47 #include <err.h> 48 #include <errno.h> 49 #include <netdb.h> 50 #include <setjmp.h> 51 #include <signal.h> 52 #include <syslog.h> 53 #include <unistd.h> 54 55 #include "dma.h" 56 57 static jmp_buf timeout_alarm; 58 char neterr[BUF_SIZE]; 59 60 char * 61 ssl_errstr(void) 62 { 63 long oerr, nerr; 64 65 oerr = 0; 66 while ((nerr = ERR_get_error()) != 0) 67 oerr = nerr; 68 69 return (ERR_error_string(oerr, NULL)); 70 } 71 72 static void 73 sig_alarm(int signo __unused) 74 { 75 longjmp(timeout_alarm, 1); 76 } 77 78 ssize_t 79 send_remote_command(int fd, const char* fmt, ...) 80 { 81 va_list va; 82 char cmd[4096]; 83 size_t len, pos; 84 int s; 85 ssize_t n; 86 87 va_start(va, fmt); 88 s = vsnprintf(cmd, sizeof(cmd) - 2, fmt, va); 89 va_end(va); 90 if (s == sizeof(cmd) - 2 || s < 0) { 91 strcpy(neterr, "Internal error: oversized command string"); 92 return (-1); 93 } 94 95 /* We *know* there are at least two more bytes available */ 96 strcat(cmd, "\r\n"); 97 len = strlen(cmd); 98 99 if (((config->features & SECURETRANS) != 0) && 100 ((config->features & NOSSL) == 0)) { 101 while ((s = SSL_write(config->ssl, (const char*)cmd, len)) <= 0) { 102 s = SSL_get_error(config->ssl, s); 103 if (s != SSL_ERROR_WANT_READ && 104 s != SSL_ERROR_WANT_WRITE) { 105 strncpy(neterr, ssl_errstr(), sizeof(neterr)); 106 return (-1); 107 } 108 } 109 } 110 else { 111 pos = 0; 112 while (pos < len) { 113 n = write(fd, cmd + pos, len - pos); 114 if (n < 0) 115 return (-1); 116 pos += n; 117 } 118 } 119 120 return (len); 121 } 122 123 int 124 read_remote(int fd, int extbufsize, char *extbuf) 125 { 126 ssize_t rlen = 0; 127 size_t pos, len; 128 char buff[BUF_SIZE]; 129 int done = 0, status = 0, extbufpos = 0; 130 131 if (signal(SIGALRM, sig_alarm) == SIG_ERR) { 132 snprintf(neterr, sizeof(neterr), "SIGALRM error: %s", 133 strerror(errno)); 134 return (-1); 135 } 136 if (setjmp(timeout_alarm) != 0) { 137 snprintf(neterr, sizeof(neterr), "Timeout reached"); 138 return (-1); 139 } 140 alarm(CON_TIMEOUT); 141 142 /* 143 * Remote reading code from femail.c written by Henning Brauer of 144 * OpenBSD and released under a BSD style license. 145 */ 146 for (len = pos = 0; !done; ) { 147 rlen = 0; 148 if (pos == 0 || 149 (pos > 0 && memchr(buff + pos, '\n', len - pos) == NULL)) { 150 memmove(buff, buff + pos, len - pos); 151 len -= pos; 152 pos = 0; 153 if (((config->features & SECURETRANS) != 0) && 154 (config->features & NOSSL) == 0) { 155 if ((rlen = SSL_read(config->ssl, buff + len, 156 sizeof(buff) - len)) == -1) { 157 strncpy(neterr, ssl_errstr(), sizeof(neterr)); 158 return (-1); 159 } 160 } else { 161 if ((rlen = read(fd, buff + len, sizeof(buff) - len)) == -1) { 162 strncpy(neterr, strerror(errno), sizeof(neterr)); 163 return (-1); 164 } 165 } 166 len += rlen; 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 && extbufsize > 0 175 && extbuf != NULL) { 176 /* do not write over the bounds of the buffer */ 177 if(extbufpos + rlen > (extbufsize - 1)) { 178 rlen = extbufsize - extbufpos; 179 } 180 memcpy(extbuf + extbufpos, buff + len - rlen, rlen); 181 extbufpos += rlen; 182 } 183 for (; pos < len && buff[pos] >= '0' && buff[pos] <= '9'; pos++) 184 ; /* Do nothing */ 185 186 if (pos == len) 187 return (0); 188 189 if (buff[pos] == ' ') { 190 done = 1; 191 } else if (buff[pos] != '-') { 192 strcpy(neterr, "invalid syntax in reply from server"); 193 return (-1); 194 } 195 196 /* skip up to \n */ 197 for (; pos < len && buff[pos - 1] != '\n'; pos++) 198 ; /* Do nothing */ 199 200 } 201 alarm(0); 202 203 buff[len] = '\0'; 204 while (len > 0 && (buff[len - 1] == '\r' || buff[len - 1] == '\n')) 205 buff[--len] = '\0'; 206 snprintf(neterr, sizeof(neterr), "%s", buff); 207 status = atoi(buff); 208 return (status/100); 209 } 210 211 /* 212 * Handle SMTP authentication 213 */ 214 static int 215 smtp_login(int fd, char *login, char* password) 216 { 217 char *temp; 218 int len, res = 0; 219 220 res = smtp_auth_md5(fd, login, password); 221 if (res == 0) { 222 return (0); 223 } else if (res == -2) { 224 /* 225 * If the return code is -2, then then the login attempt failed, 226 * do not try other login mechanisms 227 */ 228 return (1); 229 } 230 231 if ((config->features & INSECURE) != 0 || 232 (config->features & SECURETRANS) != 0) { 233 /* Send AUTH command according to RFC 2554 */ 234 send_remote_command(fd, "AUTH LOGIN"); 235 if (read_remote(fd, 0, NULL) != 3) { 236 syslog(LOG_NOTICE, "remote delivery deferred:" 237 " AUTH login not available: %s", 238 neterr); 239 return (1); 240 } 241 242 len = base64_encode(login, strlen(login), &temp); 243 if (len < 0) { 244 encerr: 245 syslog(LOG_ERR, "can not encode auth reply: %m"); 246 return (1); 247 } 248 249 send_remote_command(fd, "%s", temp); 250 free(temp); 251 res = read_remote(fd, 0, NULL); 252 if (res != 3) { 253 syslog(LOG_NOTICE, "remote delivery %s: AUTH login failed: %s", 254 res == 5 ? "failed" : "deferred", neterr); 255 return (res == 5 ? -1 : 1); 256 } 257 258 len = base64_encode(password, strlen(password), &temp); 259 if (len < 0) 260 goto encerr; 261 262 send_remote_command(fd, "%s", temp); 263 free(temp); 264 res = read_remote(fd, 0, NULL); 265 if (res != 2) { 266 syslog(LOG_NOTICE, "remote delivery %s: Authentication failed: %s", 267 res == 5 ? "failed" : "deferred", neterr); 268 return (res == 5 ? -1 : 1); 269 } 270 } else { 271 syslog(LOG_WARNING, "non-encrypted SMTP login is disabled in config, so skipping it. "); 272 return (1); 273 } 274 275 return (0); 276 } 277 278 static int 279 open_connection(const char *host) 280 { 281 struct addrinfo hints, *res, *res0; 282 char servname[128]; 283 const char *errmsg = NULL; 284 int fd, error = 0, port; 285 286 if (config->port != 0) 287 port = config->port; 288 else 289 port = SMTP_PORT; 290 291 /* XXX FIXME get MX record of host */ 292 /* Shamelessly taken from getaddrinfo(3) */ 293 memset(&hints, 0, sizeof(hints)); 294 hints.ai_family = PF_UNSPEC; 295 hints.ai_socktype = SOCK_STREAM; 296 hints.ai_protocol = IPPROTO_TCP; 297 298 snprintf(servname, sizeof(servname), "%d", port); 299 error = getaddrinfo(host, servname, &hints, &res0); 300 if (error) { 301 syslog(LOG_NOTICE, "remote delivery deferred: %s", gai_strerror(error)); 302 return (-1); 303 } 304 fd = -1; 305 for (res = res0; res; res = res->ai_next) { 306 fd=socket(res->ai_family, res->ai_socktype, res->ai_protocol); 307 if (fd < 0) { 308 errmsg = "socket failed"; 309 continue; 310 } 311 if (connect(fd, res->ai_addr, res->ai_addrlen) < 0) { 312 errmsg = "connect failed"; 313 close(fd); 314 fd = -1; 315 continue; 316 } 317 break; 318 } 319 if (fd < 0) { 320 syslog(LOG_NOTICE, "remote delivery deferred: %s (%s:%s)", 321 errmsg, host, servname); 322 freeaddrinfo(res0); 323 return (-1); 324 } 325 freeaddrinfo(res0); 326 return (fd); 327 } 328 329 static void 330 close_connection(int fd) 331 { 332 if (((config->features & SECURETRANS) != 0) && 333 ((config->features & NOSSL) == 0)) 334 SSL_shutdown(config->ssl); 335 336 if (config->ssl != NULL) 337 SSL_free(config->ssl); 338 339 close(fd); 340 } 341 342 int 343 deliver_remote(struct qitem *it, const char **errmsg) 344 { 345 struct authuser *a; 346 char *host, line[1000]; 347 int fd, error = 0, do_auth = 0, res = 0; 348 size_t linelen; 349 /* asprintf can't take const */ 350 void *errmsgc = __DECONST(char **, errmsg); 351 352 if (fseek(it->mailf, 0, SEEK_SET) != 0) { 353 asprintf(errmsgc, "can not seek: %s", strerror(errno)); 354 return (-1); 355 } 356 357 host = strrchr(it->addr, '@'); 358 /* Should not happen */ 359 if (host == NULL) { 360 asprintf(errmsgc, "Internal error: badly formed address %s", 361 it->addr); 362 return(-1); 363 } else { 364 /* Step over the @ */ 365 host++; 366 } 367 368 /* Smarthost support? */ 369 if (config->smarthost != NULL && strlen(config->smarthost) > 0) { 370 syslog(LOG_INFO, "using smarthost (%s:%i)", 371 config->smarthost, config->port); 372 host = config->smarthost; 373 } 374 375 fd = open_connection(host); 376 if (fd < 0) 377 return (1); 378 379 /* Check first reply from remote host */ 380 config->features |= NOSSL; 381 res = read_remote(fd, 0, NULL); 382 if (res != 2) { 383 syslog(LOG_WARNING, "Invalid initial response: %i", res); 384 return(1); 385 } 386 config->features &= ~NOSSL; 387 388 if ((config->features & SECURETRANS) != 0) { 389 error = smtp_init_crypto(fd, config->features); 390 if (error >= 0) 391 syslog(LOG_DEBUG, "SSL initialization successful"); 392 else 393 goto out; 394 } 395 396 /* XXX allow HELO fallback */ 397 /* XXX record ESMTP keywords */ 398 send_remote_command(fd, "EHLO %s", hostname()); 399 if (read_remote(fd, 0, NULL) != 2) { 400 syslog(LOG_WARNING, "remote delivery deferred: EHLO failed: %s", neterr); 401 asprintf(errmsgc, "%s did not like our EHLO:\n%s", 402 host, neterr); 403 return (-1); 404 } 405 406 /* 407 * Use SMTP authentication if the user defined an entry for the remote 408 * or smarthost 409 */ 410 SLIST_FOREACH(a, &authusers, next) { 411 if (strcmp(a->host, host) == 0) { 412 do_auth = 1; 413 break; 414 } 415 } 416 417 if (do_auth == 1) { 418 /* 419 * Check if the user wants plain text login without using 420 * encryption. 421 */ 422 syslog(LOG_INFO, "using SMTP authentication"); 423 error = smtp_login(fd, a->login, a->password); 424 if (error < 0) { 425 syslog(LOG_ERR, "remote delivery failed:" 426 " SMTP login failed: %m"); 427 asprintf(errmsgc, "SMTP login to %s failed", host); 428 return (-1); 429 } 430 /* SMTP login is not available, so try without */ 431 else if (error > 0) { 432 syslog(LOG_WARNING, "SMTP login not available. Trying without."); 433 } 434 } 435 436 #define READ_REMOTE_CHECK(c, exp) \ 437 res = read_remote(fd, 0, NULL); \ 438 if (res == 5) { \ 439 syslog(LOG_ERR, "remote delivery failed: " \ 440 c " failed: %s", neterr); \ 441 asprintf(errmsgc, "%s did not like our " c ":\n%s", \ 442 host, neterr); \ 443 return (-1); \ 444 } else if (res != exp) { \ 445 syslog(LOG_NOTICE, "remote delivery deferred: " \ 446 c " failed: %s", neterr); \ 447 return (1); \ 448 } 449 450 /* XXX send ESMTP ENVID, RET (FULL/HDRS) and 8BITMIME */ 451 send_remote_command(fd, "MAIL FROM:<%s>", it->sender); 452 READ_REMOTE_CHECK("MAIL FROM", 2); 453 454 /* XXX send ESMTP ORCPT */ 455 send_remote_command(fd, "RCPT TO:<%s>", it->addr); 456 READ_REMOTE_CHECK("RCPT TO", 2); 457 458 send_remote_command(fd, "DATA"); 459 READ_REMOTE_CHECK("DATA", 3); 460 461 error = 0; 462 while (!feof(it->mailf)) { 463 if (fgets(line, sizeof(line), it->mailf) == NULL) 464 break; 465 linelen = strlen(line); 466 if (linelen == 0 || line[linelen - 1] != '\n') { 467 syslog(LOG_CRIT, "remote delivery failed: corrupted queue file"); 468 *errmsg = "corrupted queue file"; 469 error = -1; 470 goto out; 471 } 472 473 /* Remove trailing \n's and escape leading dots */ 474 trim_line(line); 475 476 /* 477 * If the first character is a dot, we escape it so the line 478 * length increases 479 */ 480 if (line[0] == '.') 481 linelen++; 482 483 if (send_remote_command(fd, "%s", line) != (ssize_t)linelen+1) { 484 syslog(LOG_NOTICE, "remote delivery deferred: write error"); 485 error = 1; 486 goto out; 487 } 488 } 489 490 send_remote_command(fd, "."); 491 READ_REMOTE_CHECK("final DATA", 2); 492 493 send_remote_command(fd, "QUIT"); 494 if (read_remote(fd, 0, NULL) != 2) 495 syslog(LOG_INFO, "remote delivery succeeded but QUIT failed: %s", neterr); 496 out: 497 498 close_connection(fd); 499 return (error); 500 } 501 502