libexec/dma/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
  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)
  74 {
  75         (void)signo;    /* so that gcc doesn't complain */
  76         longjmp(timeout_alarm, 1);
  77 }
  78
  79 ssize_t
  80 send_remote_command(int fd, const char* fmt, ...)
  81 {
  82         va_list va;
  83         char cmd[4096];
  84         size_t len, pos;
  85         int s;
  86         ssize_t n;
  87
  88         va_start(va, fmt);
  89         s = vsnprintf(cmd, sizeof(cmd) - 2, fmt, va);
  90         va_end(va);
  91         if (s == sizeof(cmd) - 2 || s < 0) {
  92                 strcpy(neterr, "Internal error: oversized command string");
  93                 return (-1);
  94         }
  95
  96         /* We *know* there are at least two more bytes available */
  97         strcat(cmd, "\r\n");
  98         len = strlen(cmd);
  99
 100         if (((config.features & SECURETRANS) != 0) &&
 101             ((config.features & NOSSL) == 0)) {
 102                 while ((s = SSL_write(config.ssl, (const char*)cmd, len)) <= 0) {
 103                         s = SSL_get_error(config.ssl, s);
 104                         if (s != SSL_ERROR_WANT_READ &&
 105                             s != SSL_ERROR_WANT_WRITE) {
 106                                 strncpy(neterr, ssl_errstr(), sizeof(neterr));
 107                                 return (-1);
 108                         }
 109                 }
 110         }
 111         else {
 112                 pos = 0;
 113                 while (pos < len) {
 114                         n = write(fd, cmd + pos, len - pos);
 115                         if (n < 0)
 116                                 return (-1);
 117                         pos += n;
 118                 }
 119         }
 120
 121         return (len);
 122 }
 123
 124 int
 125 read_remote(int fd, int extbufsize, char *extbuf)
 126 {
 127         ssize_t rlen = 0;
 128         size_t pos, len;
 129         char buff[BUF_SIZE];
 130         int done = 0, status = 0, extbufpos = 0;
 131
 132         if (signal(SIGALRM, sig_alarm) == SIG_ERR) {
 133                 snprintf(neterr, sizeof(neterr), "SIGALRM error: %s",
 134                     strerror(errno));
 135                 return (-1);
 136         }
 137         if (setjmp(timeout_alarm) != 0) {
 138                 snprintf(neterr, sizeof(neterr), "Timeout reached");
 139                 return (-1);
 140         }
 141         alarm(CON_TIMEOUT);
 142
 143         /*
 144          * Remote reading code from femail.c written by Henning Brauer of
 145          * OpenBSD and released under a BSD style license.
 146          */
 147         for (len = pos = 0; !done; ) {
 148                 rlen = 0;
 149                 if (pos == 0 ||
 150                     (pos > 0 && memchr(buff + pos, '\n', len - pos) == NULL)) {
 151                         memmove(buff, buff + pos, len - pos);
 152                         len -= pos;
 153                         pos = 0;
 154                         if (((config.features & SECURETRANS) != 0) &&
 155                             (config.features & NOSSL) == 0) {
 156                                 if ((rlen = SSL_read(config.ssl, buff + len,
 157                                     sizeof(buff) - len)) == -1) {
 158                                         strncpy(neterr, ssl_errstr(), sizeof(neterr));
 159                                         return (-1);
 160                                 }
 161                         } else {
 162                                 if ((rlen = read(fd, buff + len, sizeof(buff) - len)) == -1) {
 163                                         strncpy(neterr, strerror(errno), sizeof(neterr));
 164                                         return (-1);
 165                                 }
 166                         }
 167                         len += rlen;
 168                 }
 169                 /*
 170                  * If there is an external buffer with a size bigger than zero
 171                  * and as long as there is space in the external buffer and
 172                  * there are new characters read from the mailserver
 173                  * copy them to the external buffer
 174                  */
 175                 if (extbufpos <= (extbufsize - 1) && rlen && extbufsize > 0
 176                     && extbuf != NULL) {
 177                         /* do not write over the bounds of the buffer */
 178                         if(extbufpos + rlen > (extbufsize - 1)) {
 179                                 rlen = extbufsize - extbufpos;
 180                         }
 181                         memcpy(extbuf + extbufpos, buff + len - rlen, rlen);
 182                         extbufpos += rlen;
 183                 }
 184                 for (; pos < len && buff[pos] >= '0' && buff[pos] <= '9'; pos++)
 185                         ; /* Do nothing */
 186
 187                 if (pos == len)
 188                         return (0);
 189
 190                 if (buff[pos] == ' ') {
 191                         done = 1;
 192                 } else if (buff[pos] != '-') {
 193                         strcpy(neterr, "invalid syntax in reply from server");
 194                         return (-1);
 195                 }
 196
 197                 /* skip up to \n */
 198                 for (; pos < len && buff[pos - 1] != '\n'; pos++)
 199                         ; /* Do nothing */
 200
 201         }
 202         alarm(0);
 203
 204         buff[len] = '\0';
 205         while (len > 0 && (buff[len - 1] == '\r' || buff[len - 1] == '\n'))
 206                 buff[--len] = '\0';
 207         snprintf(neterr, sizeof(neterr), "%s", buff);
 208         status = atoi(buff);
 209         return (status/100);
 210 }
 211
 212 /*
 213  * Handle SMTP authentication
 214  */
 215 static int
 216 smtp_login(int fd, char *login, char* password)
 217 {
 218         char *temp;
 219         int len, res = 0;
 220
 221         res = smtp_auth_md5(fd, login, password);
 222         if (res == 0) {
 223                 return (0);
 224         } else if (res == -2) {
 225         /*
 226          * If the return code is -2, then then the login attempt failed,
 227          * do not try other login mechanisms
 228          */
 229                 return (1);
 230         }
 231
 232         if ((config.features & INSECURE) != 0 ||
 233             (config.features & SECURETRANS) != 0) {
 234                 /* Send AUTH command according to RFC 2554 */
 235                 send_remote_command(fd, "AUTH LOGIN");
 236                 if (read_remote(fd, 0, NULL) != 3) {
 237                         syslog(LOG_NOTICE, "remote delivery deferred:"
 238                                         " AUTH login not available: %s",
 239                                         neterr);
 240                         return (1);
 241                 }
 242
 243                 len = base64_encode(login, strlen(login), &temp);
 244                 if (len < 0) {
 245 encerr:
 246                         syslog(LOG_ERR, "can not encode auth reply: %m");
 247                         return (1);
 248                 }
 249
 250                 send_remote_command(fd, "%s", temp);
 251                 free(temp);
 252                 res = read_remote(fd, 0, NULL);
 253                 if (res != 3) {
 254                         syslog(LOG_NOTICE, "remote delivery %s: AUTH login failed: %s",
 255                                res == 5 ? "failed" : "deferred", neterr);
 256                         return (res == 5 ? -1 : 1);
 257                 }
 258
 259                 len = base64_encode(password, strlen(password), &temp);
 260                 if (len < 0)
 261                         goto encerr;
 262
 263                 send_remote_command(fd, "%s", temp);
 264                 free(temp);
 265                 res = read_remote(fd, 0, NULL);
 266                 if (res != 2) {
 267                         syslog(LOG_NOTICE, "remote delivery %s: Authentication failed: %s",
 268                                         res == 5 ? "failed" : "deferred", neterr);
 269                         return (res == 5 ? -1 : 1);
 270                 }
 271         } else {
 272                 syslog(LOG_WARNING, "non-encrypted SMTP login is disabled in config, so skipping it. ");
 273                 return (1);
 274         }
 275
 276         return (0);
 277 }
 278
 279 static int
 280 open_connection(struct mx_hostentry *h)
 281 {
 282         int fd;
 283
 284         syslog(LOG_INFO, "trying remote delivery to %s [%s] pref %d",
 285                h->host, h->addr, h->pref);
 286
 287         fd = socket(h->ai.ai_family, h->ai.ai_socktype, h->ai.ai_protocol);
 288         if (fd < 0) {
 289                 syslog(LOG_INFO, "socket for %s [%s] failed: %m",
 290                        h->host, h->addr);
 291                 return (-1);
 292         }
 293
 294         if (connect(fd, (struct sockaddr *)&h->sa, h->ai.ai_addrlen) < 0) {
 295                 syslog(LOG_INFO, "connect to %s [%s] failed: %m",
 296                        h->host, h->addr);
 297                 close(fd);
 298                 return (-1);
 299         }
 300
 301         return (fd);
 302 }
 303
 304 static void
 305 close_connection(int fd)
 306 {
 307         if (((config.features & SECURETRANS) != 0) &&
 308             ((config.features & NOSSL) == 0))
 309                 SSL_shutdown(config.ssl);
 310
 311         if (config.ssl != NULL)
 312                 SSL_free(config.ssl);
 313
 314         close(fd);
 315 }
 316
 317 static int
 318 deliver_to_host(struct qitem *it, struct mx_hostentry *host, void *errmsgc)
 319 {
 320         struct authuser *a;
 321         char line[1000];
 322         size_t linelen;
 323         int fd, error = 0, do_auth = 0, res = 0;
 324
 325         if (fseek(it->mailf, 0, SEEK_SET) != 0) {
 326                 asprintf(errmsgc, "can not seek: %s", strerror(errno));
 327                 return (-1);
 328         }
 329
 330         fd = open_connection(host);
 331         if (fd < 0)
 332                 return (1);
 333
 334 #define READ_REMOTE_CHECK(c, exp)       \
 335         res = read_remote(fd, 0, NULL); \
 336         if (res == 5) { \
 337                 syslog(LOG_ERR, "remote delivery to %s [%s] failed after %s: %s", \
 338                        host->host, host->addr, c, neterr); \
 339                 asprintf(errmsgc, "%s [%s] did not like our %s:\n%s", \
 340                          host->host, host->addr, c, neterr); \
 341                 return (-1); \
 342         } else if (res != exp) { \
 343                 syslog(LOG_NOTICE, "remote delivery deferred: %s [%s] failed after %s: %s", \
 344                        host->host, host->addr, c, neterr); \
 345                 return (1); \
 346         }
 347
 348         /* Check first reply from remote host */
 349         config.features |= NOSSL;
 350         READ_REMOTE_CHECK("connect", 2);
 351
 352         config.features &= ~NOSSL;
 353
 354         if ((config.features & SECURETRANS) != 0) {
 355                 error = smtp_init_crypto(fd, config.features);
 356                 if (error == 0)
 357                         syslog(LOG_DEBUG, "SSL initialization successful");
 358                 else
 359                         goto out;
 360         }
 361
 362         /* XXX allow HELO fallback */
 363         /* XXX record ESMTP keywords */
 364         send_remote_command(fd, "EHLO %s", hostname());
 365         READ_REMOTE_CHECK("EHLO", 2);
 366
 367         /*
 368          * Use SMTP authentication if the user defined an entry for the remote
 369          * or smarthost
 370          */
 371         SLIST_FOREACH(a, &authusers, next) {
 372                 if (strcmp(a->host, host->host) == 0) {
 373                         do_auth = 1;
 374                         break;
 375                 }
 376         }
 377
 378         if (do_auth == 1) {
 379                 /*
 380                  * Check if the user wants plain text login without using
 381                  * encryption.
 382                  */
 383                 syslog(LOG_INFO, "using SMTP authentication for user %s", a->login);
 384                 error = smtp_login(fd, a->login, a->password);
 385                 if (error < 0) {
 386                         syslog(LOG_ERR, "remote delivery failed:"
 387                                         " SMTP login failed: %m");
 388                         asprintf(errmsgc, "SMTP login to %s failed", host->host);
 389                         return (-1);
 390                 }
 391                 /* SMTP login is not available, so try without */
 392                 else if (error > 0) {
 393                         syslog(LOG_WARNING, "SMTP login not available. Trying without.");
 394                 }
 395         }
 396
 397         /* XXX send ESMTP ENVID, RET (FULL/HDRS) and 8BITMIME */
 398         send_remote_command(fd, "MAIL FROM:<%s>", it->sender);
 399         READ_REMOTE_CHECK("MAIL FROM", 2);
 400
 401         /* XXX send ESMTP ORCPT */
 402         send_remote_command(fd, "RCPT TO:<%s>", it->addr);
 403         READ_REMOTE_CHECK("RCPT TO", 2);
 404
 405         send_remote_command(fd, "DATA");
 406         READ_REMOTE_CHECK("DATA", 3);
 407
 408         error = 0;
 409         while (!feof(it->mailf)) {
 410                 if (fgets(line, sizeof(line), it->mailf) == NULL)
 411                         break;
 412                 linelen = strlen(line);
 413                 if (linelen == 0 || line[linelen - 1] != '\n') {
 414                         syslog(LOG_CRIT, "remote delivery failed: corrupted queue file");
 415                         *(const char **)errmsgc = "corrupted queue file";
 416                         error = -1;
 417                         goto out;
 418                 }
 419
 420                 /* Remove trailing \n's and escape leading dots */
 421                 trim_line(line);
 422
 423                 /*
 424                  * If the first character is a dot, we escape it so the line
 425                  * length increases
 426                 */
 427                 if (line[0] == '.')
 428                         linelen++;
 429
 430                 if (send_remote_command(fd, "%s", line) != (ssize_t)linelen+1) {
 431                         syslog(LOG_NOTICE, "remote delivery deferred: write error");
 432                         error = 1;
 433                         goto out;
 434                 }
 435         }
 436
 437         send_remote_command(fd, ".");
 438         READ_REMOTE_CHECK("final DATA", 2);
 439
 440         send_remote_command(fd, "QUIT");
 441         if (read_remote(fd, 0, NULL) != 2)
 442                 syslog(LOG_INFO, "remote delivery succeeded but QUIT failed: %s", neterr);
 443 out:
 444
 445         close_connection(fd);
 446         return (error);
 447 }
 448
 449 int
 450 deliver_remote(struct qitem *it, const char **errmsg)
 451 {
 452         /* asprintf can't take const */
 453         void *errmsgc = __DECONST(char **, errmsg);
 454         struct mx_hostentry *hosts, *h;
 455         const char *host;
 456         int port;
 457         int error = 1, smarthost = 0;
 458
 459         host = strrchr(it->addr, '@');
 460         /* Should not happen */
 461         if (host == NULL) {
 462                 asprintf(errmsgc, "Internal error: badly formed address %s",
 463                     it->addr);
 464                 return(-1);
 465         } else {
 466                 /* Step over the @ */
 467                 host++;
 468         }
 469
 470         port = SMTP_PORT;
 471
 472         /* Smarthost support? */
 473         if (config.smarthost != NULL) {
 474                 host = config.smarthost;
 475                 port = config.port;
 476                 syslog(LOG_INFO, "using smarthost (%s:%i)", host, port);
 477                 smarthost = 1;
 478         }
 479
 480         error = dns_get_mx_list(host, port, &hosts, smarthost);
 481         if (error) {
 482                 syslog(LOG_NOTICE, "remote delivery %s: DNS failure (%s)",
 483                        error < 0 ? "failed" : "deferred",
 484                        host);
 485                 return (error);
 486         }
 487
 488         for (h = hosts; *h->host != 0; h++) {
 489                 switch (deliver_to_host(it, h, errmsgc)) {
 490                 case 0:
 491                         /* success */
 492                         error = 0;
 493                         goto out;
 494                 case 1:
 495                         /* temp failure */
 496                         error = 1;
 497                         break;
 498                 default:
 499                         /* perm failure */
 500                         error = -1;
 501                         goto out;
 502                 }
 503         }
 504 out:
 505         free(hosts);
 506
 507         return (error);
 508 }