net.c

   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  * $DragonFly: src/libexec/dma/net.c,v 1.9 2008/09/30 17:47:21 swildner Exp $
  36  */
  37
  38 #include <sys/param.h>
  39 #include <sys/queue.h>
  40 #include <sys/stat.h>
  41 #include <sys/types.h>
  42 #include <sys/socket.h>
  43 #include <netinet/in.h>
  44 #include <arpa/inet.h>
  45
  46 #include <openssl/ssl.h>
  47 #include <openssl/err.h>
  48
  49 #include <err.h>
  50 #include <errno.h>
  51 #include <netdb.h>
  52 #include <setjmp.h>
  53 #include <signal.h>
  54 #include <syslog.h>
  55 #include <unistd.h>
  56
  57 #include "dma.h"
  58
  59 static jmp_buf timeout_alarm;
  60 char neterr[BUF_SIZE];
  61
  62 char *
  63 ssl_errstr(void)
  64 {
  65         long oerr, nerr;
  66
  67         oerr = 0;
  68         while ((nerr = ERR_get_error()) != 0)
  69                 oerr = nerr;
  70
  71         return (ERR_error_string(oerr, NULL));
  72 }
  73
  74 static void
  75 sig_alarm(int signo __unused)
  76 {
  77         longjmp(timeout_alarm, 1);
  78 }
  79
  80 ssize_t
  81 send_remote_command(int fd, const char* fmt, ...)
  82 {
  83         va_list va;
  84         char cmd[4096];
  85         size_t len, pos;
  86         int s;
  87         ssize_t n;
  88
  89         va_start(va, fmt);
  90         s = vsnprintf(cmd, sizeof(cmd) - 2, fmt, va);
  91         va_end(va);
  92         if (s == sizeof(cmd) - 2 || s < 0) {
  93                 strcpy(neterr, "Internal error: oversized command string");
  94                 return (-1);
  95         }
  96
  97         /* We *know* there are at least two more bytes available */
  98         strcat(cmd, "\r\n");
  99         len = strlen(cmd);
 100
 101         if (((config->features & SECURETRANS) != 0) &&
 102             ((config->features & NOSSL) == 0)) {
 103                 while ((s = SSL_write(config->ssl, (const char*)cmd, len)) <= 0) {
 104                         s = SSL_get_error(config->ssl, s);
 105                         if (s != SSL_ERROR_WANT_READ &&
 106                             s != SSL_ERROR_WANT_WRITE) {
 107                                 strncpy(neterr, ssl_errstr(), sizeof(neterr));
 108                                 return (-1);
 109                         }
 110                 }
 111         }
 112         else {
 113                 pos = 0;
 114                 while (pos < len) {
 115                         n = write(fd, cmd + pos, len - pos);
 116                         if (n < 0)
 117                                 return (-1);
 118                         pos += n;
 119                 }
 120         }
 121
 122         return (len);
 123 }
 124
 125 int
 126 read_remote(int fd, int extbufsize, char *extbuf)
 127 {
 128         ssize_t rlen = 0;
 129         size_t pos, len;
 130         char buff[BUF_SIZE];
 131         int done = 0, status = 0, extbufpos = 0;
 132
 133         if (signal(SIGALRM, sig_alarm) == SIG_ERR) {
 134                 snprintf(neterr, sizeof(neterr), "SIGALRM error: %s",
 135                     strerror(errno));
 136                 return (-1);
 137         }
 138         if (setjmp(timeout_alarm) != 0) {
 139                 snprintf(neterr, sizeof(neterr), "Timeout reached");
 140                 return (-1);
 141         }
 142         alarm(CON_TIMEOUT);
 143
 144         /*
 145          * Remote reading code from femail.c written by Henning Brauer of
 146          * OpenBSD and released under a BSD style license.
 147          */
 148         for (len = pos = 0; !done; ) {
 149                 rlen = 0;
 150                 if (pos == 0 ||
 151                     (pos > 0 && memchr(buff + pos, '\n', len - pos) == NULL)) {
 152                         memmove(buff, buff + pos, len - pos);
 153                         len -= pos;
 154                         pos = 0;
 155                         if (((config->features & SECURETRANS) != 0) &&
 156                             (config->features & NOSSL) == 0) {
 157                                 if ((rlen = SSL_read(config->ssl, buff + len,
 158                                     sizeof(buff) - len)) == -1) {
 159                                         strncpy(neterr, ssl_errstr(), sizeof(neterr));
 160                                         return (-1);
 161                                 }
 162                         } else {
 163                                 if ((rlen = read(fd, buff + len, sizeof(buff) - len)) == -1) {
 164                                         strncpy(neterr, strerror(errno), sizeof(neterr));
 165                                         return (-1);
 166                                 }
 167                         }
 168                         len += rlen;
 169                 }
 170                 /*
 171                  * If there is an external buffer with a size bigger than zero
 172                  * and as long as there is space in the external buffer and
 173                  * there are new characters read from the mailserver
 174                  * copy them to the external buffer
 175                  */
 176                 if (extbufpos <= (extbufsize - 1) && rlen && extbufsize > 0
 177                     && extbuf != NULL) {
 178                         /* do not write over the bounds of the buffer */
 179                         if(extbufpos + rlen > (extbufsize - 1)) {
 180                                 rlen = extbufsize - extbufpos;
 181                         }
 182                         memcpy(extbuf + extbufpos, buff + len - rlen, rlen);
 183                         extbufpos += rlen;
 184                 }
 185                 for (; pos < len && buff[pos] >= '0' && buff[pos] <= '9'; pos++)
 186                         ; /* Do nothing */
 187
 188                 if (pos == len)
 189                         return (0);
 190
 191                 if (buff[pos] == ' ') {
 192                         done = 1;
 193                 } else if (buff[pos] != '-') {
 194                         strcpy(neterr, "invalid syntax in reply from server");
 195                         return (-1);
 196                 }
 197
 198                 /* skip up to \n */
 199                 for (; pos < len && buff[pos - 1] != '\n'; pos++)
 200                         ; /* Do nothing */
 201
 202         }
 203         alarm(0);
 204
 205         buff[len] = '\0';
 206         while (len > 0 && (buff[len - 1] == '\r' || buff[len - 1] == '\n'))
 207                 buff[--len] = '\0';
 208         snprintf(neterr, sizeof(neterr), "%s", buff);
 209         status = atoi(buff);
 210         return (status/100);
 211 }
 212
 213 /*
 214  * Handle SMTP authentication
 215  */
 216 static int
 217 smtp_login(struct qitem *it, int fd, char *login, char* password)
 218 {
 219         char *temp;
 220         int len, res = 0;
 221
 222         res = smtp_auth_md5(it, fd, login, password);
 223         if (res == 0) {
 224                 return (0);
 225         } else if (res == -2) {
 226         /*
 227          * If the return code is -2, then then the login attempt failed,
 228          * do not try other login mechanisms
 229          */
 230                 return (1);
 231         }
 232
 233         if ((config->features & INSECURE) != 0 ||
 234             (config->features & SECURETRANS) != 0) {
 235                 /* Send AUTH command according to RFC 2554 */
 236                 send_remote_command(fd, "AUTH LOGIN");
 237                 if (read_remote(fd, 0, NULL) != 3) {
 238                         syslog(LOG_NOTICE, "%s: remote delivery deferred:"
 239                                         " AUTH login not available: %s",
 240                                         it->queueid, neterr);
 241                         return (1);
 242                 }
 243
 244                 len = base64_encode(login, strlen(login), &temp);
 245                 if (len < 0) {
 246 encerr:
 247                         syslog(LOG_ERR, "%s: can not encode auth reply: %m",
 248                                it->queueid);
 249                         return (1);
 250                 }
 251
 252                 send_remote_command(fd, "%s", temp);
 253                 free(temp);
 254                 res = read_remote(fd, 0, NULL);
 255                 if (res != 3) {
 256                         syslog(LOG_NOTICE, "%s: remote delivery %s: AUTH login failed: %s",
 257                                it->queueid, res == 5 ? "failed" : "deferred", neterr);
 258                         return (res == 5 ? -1 : 1);
 259                 }
 260
 261                 len = base64_encode(password, strlen(password), &temp);
 262                 if (len < 0)
 263                         goto encerr;
 264
 265                 send_remote_command(fd, "%s", temp);
 266                 free(temp);
 267                 res = read_remote(fd, 0, NULL);
 268                 if (res != 2) {
 269                         syslog(LOG_NOTICE, "%s: remote delivery %s: Authentication failed: %s",
 270                                         it->queueid, res == 5 ? "failed" : "deferred", neterr);
 271                         return (res == 5 ? -1 : 1);
 272                 }
 273         } else {
 274                 syslog(LOG_WARNING, "%s: non-encrypted SMTP login is disabled in config, so skipping it. ",
 275                                 it->queueid);
 276                 return (1);
 277         }
 278
 279         return (0);
 280 }
 281
 282 static int
 283 open_connection(struct qitem *it, const char *host)
 284 {
 285         struct addrinfo hints, *res, *res0;
 286         char servname[128];
 287         const char *errmsg = NULL;
 288         int fd, error = 0, port;
 289
 290         if (config->port != 0)
 291                 port = config->port;
 292         else
 293                 port = SMTP_PORT;
 294
 295         /* FIXME get MX record of host */
 296         /* Shamelessly taken from getaddrinfo(3) */
 297         memset(&hints, 0, sizeof(hints));
 298         hints.ai_family = PF_UNSPEC;
 299         hints.ai_socktype = SOCK_STREAM;
 300         hints.ai_protocol = IPPROTO_TCP;
 301
 302         snprintf(servname, sizeof(servname), "%d", port);
 303         error = getaddrinfo(host, servname, &hints, &res0);
 304         if (error) {
 305                 syslog(LOG_NOTICE, "%s: remote delivery deferred: "
 306                        "%s: %m", it->queueid, gai_strerror(error));
 307                 return (-1);
 308         }
 309         fd = -1;
 310         for (res = res0; res; res = res->ai_next) {
 311                 fd=socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 312                 if (fd < 0) {
 313                         errmsg = "socket failed";
 314                         continue;
 315                 }
 316                 if (connect(fd, res->ai_addr, res->ai_addrlen) < 0) {
 317                         errmsg = "connect failed";
 318                         close(fd);
 319                         fd = -1;
 320                         continue;
 321                 }
 322                 break;
 323         }
 324         if (fd < 0) {
 325                 syslog(LOG_NOTICE, "%s: remote delivery deferred: %s (%s:%s)",
 326                         it->queueid, errmsg, host, servname);
 327                 freeaddrinfo(res0);
 328                 return (-1);
 329         }
 330         freeaddrinfo(res0);
 331         return (fd);
 332 }
 333
 334 static void
 335 close_connection(int fd)
 336 {
 337         if (((config->features & SECURETRANS) != 0) &&
 338             ((config->features & NOSSL) == 0))
 339                 SSL_shutdown(config->ssl);
 340
 341         if (config->ssl != NULL)
 342                 SSL_free(config->ssl);
 343
 344         close(fd);
 345 }
 346
 347 int
 348 deliver_remote(struct qitem *it, const char **errmsg)
 349 {
 350         struct authuser *a;
 351         char *host, line[1000];
 352         int fd, error = 0, do_auth = 0, res = 0;
 353         size_t linelen;
 354         /* asprintf can't take const */
 355         void *errmsgc = __DECONST(char **, errmsg);
 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, "%s: using smarthost (%s:%i)",
 371                        it->queueid, config->smarthost, config->port);
 372                 host = config->smarthost;
 373         }
 374
 375         fd = open_connection(it, 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, "%s: Invalid initial response: %i",
 384                         it->queueid, res);
 385                 return(1);
 386         }
 387         config->features &= ~NOSSL;
 388
 389         if ((config->features & SECURETRANS) != 0) {
 390                 error = smtp_init_crypto(it, fd, config->features);
 391                 if (error >= 0)
 392                         syslog(LOG_DEBUG, "%s: SSL initialization successful",
 393                                 it->queueid);
 394                 else
 395                         goto out;
 396         }
 397
 398         send_remote_command(fd, "EHLO %s", hostname());
 399         if (read_remote(fd, 0, NULL) != 2) {
 400                 syslog(LOG_WARNING, "%s: remote delivery deferred: "
 401                        " EHLO failed: %s", it->queueid, neterr);
 402                 asprintf(errmsgc, "%s did not like our EHLO:\n%s",
 403                     host, neterr);
 404                 return (-1);
 405         }
 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) == 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, "%s: Use SMTP authentication",
 424                                 it->queueid);
 425                 error = smtp_login(it, fd, a->login, a->password);
 426                 if (error < 0) {
 427                         syslog(LOG_ERR, "%s: remote delivery failed:"
 428                                         " SMTP login failed: %m", it->queueid);
 429                         asprintf(errmsgc, "SMTP login to %s failed", host);
 430                         return (-1);
 431                 }
 432                 /* SMTP login is not available, so try without */
 433                 else if (error > 0)
 434                         syslog(LOG_WARNING, "%s: SMTP login not available."
 435                                         " Try without", it->queueid);
 436         }
 437
 438 #define READ_REMOTE_CHECK(c, exp)       \
 439         res = read_remote(fd, 0, NULL); \
 440         if (res == 5) { \
 441                 syslog(LOG_ERR, "%s: remote delivery failed: " \
 442                        c " failed: %s", it->queueid, neterr); \
 443                 asprintf(errmsgc, "%s did not like our " c ":\n%s", \
 444                     host, neterr); \
 445                 return (-1); \
 446         } else if (res != exp) { \
 447                 syslog(LOG_NOTICE, "%s: remote delivery deferred: " \
 448                        c " failed: %s", it->queueid, neterr); \
 449                 return (1); \
 450         }
 451
 452         send_remote_command(fd, "MAIL FROM:<%s>", it->sender);
 453         READ_REMOTE_CHECK("MAIL FROM", 2);
 454
 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         if (fseek(it->mailf, it->hdrlen, SEEK_SET) != 0) {
 462                 syslog(LOG_ERR, "%s: remote delivery deferred: cannot seek: %s",
 463                        it->queueid, neterr);
 464                 return (1);
 465         }
 466
 467         error = 0;
 468         while (!feof(it->mailf)) {
 469                 if (fgets(line, sizeof(line), it->mailf) == NULL)
 470                         break;
 471                 linelen = strlen(line);
 472                 if (linelen == 0 || line[linelen - 1] != '\n') {
 473                         syslog(LOG_CRIT, "%s: remote delivery failed:"
 474                                 "corrupted queue file", it->queueid);
 475                         *errmsg = "corrupted queue file";
 476                         error = -1;
 477                         goto out;
 478                 }
 479
 480                 /* Remove trailing \n's and escape leading dots */
 481                 trim_line(line);
 482
 483                 /*
 484                  * If the first character is a dot, we escape it so the line
 485                  * length increases
 486                 */
 487                 if (line[0] == '.')
 488                         linelen++;
 489
 490                 if (send_remote_command(fd, "%s", line) != (ssize_t)linelen+1) {
 491                         syslog(LOG_NOTICE, "%s: remote delivery deferred: "
 492                                 "write error", it->queueid);
 493                         error = 1;
 494                         goto out;
 495                 }
 496         }
 497
 498         send_remote_command(fd, ".");
 499         READ_REMOTE_CHECK("final DATA", 2);
 500
 501         send_remote_command(fd, "QUIT");
 502         if (read_remote(fd, 0, NULL) != 2)
 503                 syslog(LOG_INFO, "%s: remote delivery succeeded but "
 504                        "QUIT failed: %s", it->queueid, neterr);
 505 out:
 506
 507         close_connection(fd);
 508         return (error);
 509 }
 510