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 #ifdef HAVE_CRYPTO
  47 #include <openssl/ssl.h>
  48 #endif /* HAVE_CRYPTO */
  49
  50 #include <err.h>
  51 #include <errno.h>
  52 #include <netdb.h>
  53 #include <setjmp.h>
  54 #include <signal.h>
  55 #include <syslog.h>
  56 #include <unistd.h>
  57
  58 #include "dma.h"
  59
  60 extern struct config *config;
  61 extern struct authusers authusers;
  62 static jmp_buf timeout_alarm;
  63 char neterr[BUF_SIZE];
  64
  65 static void
  66 sig_alarm(int signo __unused)
  67 {
  68         longjmp(timeout_alarm, 1);
  69 }
  70
  71 ssize_t
  72 send_remote_command(int fd, const char* fmt, ...)
  73 {
  74         va_list va;
  75         char cmd[4096];
  76         size_t len, pos;
  77         int s;
  78         ssize_t n;
  79
  80         va_start(va, fmt);
  81         s = vsnprintf(cmd, sizeof(cmd) - 2, fmt, va);
  82         va_end(va);
  83         if (s == sizeof(cmd) - 2 || s < 0)
  84                 errx(1, "Internal error: oversized command string");
  85         /* We *know* there are at least two more bytes available */
  86         strcat(cmd, "\r\n");
  87         len = strlen(cmd);
  88
  89         if (((config->features & SECURETRANS) != 0) &&
  90             ((config->features & NOSSL) == 0)) {
  91                 while ((s = SSL_write(config->ssl, (const char*)cmd, len)) <= 0) {
  92                         s = SSL_get_error(config->ssl, s);
  93                         if (s != SSL_ERROR_WANT_READ &&
  94                             s != SSL_ERROR_WANT_WRITE)
  95                                 return (-1);
  96                 }
  97         }
  98         else {
  99                 pos = 0;
 100                 while (pos < len) {
 101                         n = write(fd, cmd + pos, len - pos);
 102                         if (n < 0)
 103                                 return (-1);
 104                         pos += n;
 105                 }
 106         }
 107
 108         return (len);
 109 }
 110
 111 int
 112 read_remote(int fd, int extbufsize, char *extbuf)
 113 {
 114         ssize_t rlen = 0;
 115         size_t pos, len;
 116         char buff[BUF_SIZE];
 117         int done = 0, status = 0, extbufpos = 0;
 118
 119         if (signal(SIGALRM, sig_alarm) == SIG_ERR) {
 120                 snprintf(neterr, sizeof(neterr), "SIGALRM error: %s",
 121                     strerror(errno));
 122                 return (1);
 123         }
 124         if (setjmp(timeout_alarm) != 0) {
 125                 snprintf(neterr, sizeof(neterr), "Timeout reached");
 126                 return (1);
 127         }
 128         alarm(CON_TIMEOUT);
 129
 130         /*
 131          * Remote reading code from femail.c written by Henning Brauer of
 132          * OpenBSD and released under a BSD style license.
 133          */
 134         for (len = pos = 0; !done; ) {
 135                 rlen = 0;
 136                 if (pos == 0 ||
 137                     (pos > 0 && memchr(buff + pos, '\n', len - pos) == NULL)) {
 138                         memmove(buff, buff + pos, len - pos);
 139                         len -= pos;
 140                         pos = 0;
 141                         if (((config->features & SECURETRANS) != 0) &&
 142                             (config->features & NOSSL) == 0) {
 143                                 if ((rlen = SSL_read(config->ssl, buff + len,
 144                                     sizeof(buff) - len)) == -1)
 145                                         err(1, "read");
 146                         } else {
 147                                 if ((rlen = read(fd, buff + len,
 148                                     sizeof(buff) - len)) == -1)
 149                                         err(1, "read");
 150                         }
 151                         len += rlen;
 152                 }
 153                 /*
 154                  * If there is an external buffer with a size bigger than zero
 155                  * and as long as there is space in the external buffer and
 156                  * there are new characters read from the mailserver
 157                  * copy them to the external buffer
 158                  */
 159                 if (extbufpos <= (extbufsize - 1) && rlen && extbufsize > 0
 160                     && extbuf != NULL) {
 161                         /* do not write over the bounds of the buffer */
 162                         if(extbufpos + rlen > (extbufsize - 1)) {
 163                                 rlen = extbufsize - extbufpos;
 164                         }
 165                         memcpy(extbuf + extbufpos, buff + len - rlen, rlen);
 166                         extbufpos += rlen;
 167                 }
 168                 for (; pos < len && buff[pos] >= '0' && buff[pos] <= '9'; pos++)
 169                         ; /* Do nothing */
 170
 171                 if (pos == len)
 172                         return (0);
 173
 174                 if (buff[pos] == ' ')
 175                         done = 1;
 176                 else if (buff[pos] != '-')
 177                         syslog(LOG_ERR, "invalid syntax in reply from server");
 178
 179                 /* skip up to \n */
 180                 for (; pos < len && buff[pos - 1] != '\n'; pos++)
 181                         ; /* Do nothing */
 182
 183         }
 184         alarm(0);
 185
 186         buff[len] = '\0';
 187         while (len > 0 && (buff[len - 1] == '\r' || buff[len - 1] == '\n'))
 188                 buff[--len] = '\0';
 189         snprintf(neterr, sizeof(neterr), "%s", buff);
 190         status = atoi(buff);
 191         return (status/100);
 192 }
 193
 194 /*
 195  * Handle SMTP authentication
 196  */
 197 static int
 198 smtp_login(struct qitem *it, int fd, char *login, char* password)
 199 {
 200         char *temp;
 201         int len, res = 0;
 202
 203 #ifdef HAVE_CRYPTO
 204         res = smtp_auth_md5(it, fd, login, password);
 205         if (res == 0) {
 206                 return (0);
 207         } else if (res == -2) {
 208         /*
 209          * If the return code is -2, then then the login attempt failed,
 210          * do not try other login mechanisms
 211          */
 212                 return (-1);
 213         }
 214 #endif /* HAVE_CRYPTO */
 215
 216         if ((config->features & INSECURE) != 0) {
 217                 /* Send AUTH command according to RFC 2554 */
 218                 send_remote_command(fd, "AUTH LOGIN");
 219                 if (read_remote(fd, 0, NULL) != 3) {
 220                         syslog(LOG_NOTICE, "%s: remote delivery deferred:"
 221                                         " AUTH login not available: %s",
 222                                         it->queueid, neterr);
 223                         return (1);
 224                 }
 225
 226                 len = base64_encode(login, strlen(login), &temp);
 227                 if (len <= 0)
 228                         return (-1);
 229
 230                 send_remote_command(fd, "%s", temp);
 231                 if (read_remote(fd, 0, NULL) != 3) {
 232                         syslog(LOG_NOTICE, "%s: remote delivery deferred:"
 233                                         " AUTH login failed: %s", it->queueid,
 234                                         neterr);
 235                         return (-1);
 236                 }
 237
 238                 len = base64_encode(password, strlen(password), &temp);
 239                 if (len <= 0)
 240                         return (-1);
 241
 242                 send_remote_command(fd, "%s", temp);
 243                 res = read_remote(fd, 0, NULL);
 244                 if (res == 5) {
 245                         syslog(LOG_NOTICE, "%s: remote delivery failed:"
 246                                         " Authentication failed: %s",
 247                                         it->queueid, neterr);
 248                         return (-1);
 249                 } else if (res != 2) {
 250                         syslog(LOG_NOTICE, "%s: remote delivery failed:"
 251                                         " AUTH password failed: %s",
 252                                         it->queueid, neterr);
 253                         return (-1);
 254                 }
 255         } else {
 256                 syslog(LOG_WARNING, "%s: non-encrypted SMTP login is disabled in config, so skipping it. ",
 257                                 it->queueid);
 258                 return (1);
 259         }
 260
 261         return (0);
 262 }
 263
 264 static int
 265 open_connection(struct qitem *it, const char *host)
 266 {
 267         struct addrinfo hints, *res, *res0;
 268         char servname[128];
 269         const char *errmsg = NULL;
 270         int fd, error = 0, port;
 271
 272         if (config->port != 0)
 273                 port = config->port;
 274         else
 275                 port = SMTP_PORT;
 276
 277         /* FIXME get MX record of host */
 278         /* Shamelessly taken from getaddrinfo(3) */
 279         memset(&hints, 0, sizeof(hints));
 280         hints.ai_family = PF_UNSPEC;
 281         hints.ai_socktype = SOCK_STREAM;
 282         hints.ai_protocol = IPPROTO_TCP;
 283
 284         snprintf(servname, sizeof(servname), "%d", port);
 285         error = getaddrinfo(host, servname, &hints, &res0);
 286         if (error) {
 287                 syslog(LOG_NOTICE, "%s: remote delivery deferred: "
 288                        "%s: %m", it->queueid, gai_strerror(error));
 289                 return (-1);
 290         }
 291         fd = -1;
 292         for (res = res0; res; res = res->ai_next) {
 293                 fd=socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 294                 if (fd < 0) {
 295                         errmsg = "socket failed";
 296                         continue;
 297                 }
 298                 if (connect(fd, res->ai_addr, res->ai_addrlen) < 0) {
 299                         errmsg = "connect failed";
 300                         close(fd);
 301                         fd = -1;
 302                         continue;
 303                 }
 304                 break;
 305         }
 306         if (fd < 0) {
 307                 syslog(LOG_NOTICE, "%s: remote delivery deferred: %s (%s:%s)",
 308                         it->queueid, errmsg, host, servname);
 309                 freeaddrinfo(res0);
 310                 return (-1);
 311         }
 312         freeaddrinfo(res0);
 313         return (fd);
 314 }
 315
 316 int
 317 deliver_remote(struct qitem *it, const char **errmsg)
 318 {
 319         struct authuser *a;
 320         char *host, line[1000];
 321         int fd, error = 0, do_auth = 0, res = 0;
 322         size_t linelen;
 323         /* asprintf can't take const */
 324         void *errmsgc = __DECONST(char **, errmsg);
 325
 326         host = strrchr(it->addr, '@');
 327         /* Should not happen */
 328         if (host == NULL) {
 329                 asprintf(errmsgc, "Internal error: badly formed address %s",
 330                     it->addr);
 331                 return(-1);
 332         } else {
 333                 /* Step over the @ */
 334                 host++;
 335         }
 336
 337         /* Smarthost support? */
 338         if (config->smarthost != NULL && strlen(config->smarthost) > 0) {
 339                 syslog(LOG_INFO, "%s: using smarthost (%s:%i)",
 340                        it->queueid, config->smarthost, config->port);
 341                 host = config->smarthost;
 342         }
 343
 344         fd = open_connection(it, host);
 345         if (fd < 0)
 346                 return (1);
 347
 348         /* Check first reply from remote host */
 349         config->features |= NOSSL;
 350         res = read_remote(fd, 0, NULL);
 351         if (res != 2) {
 352                 syslog(LOG_WARNING, "%s: Invalid initial response: %i",
 353                         it->queueid, res);
 354                 return(1);
 355         }
 356         config->features &= ~NOSSL;
 357
 358 #ifdef HAVE_CRYPTO
 359         if ((config->features & SECURETRANS) != 0) {
 360                 error = smtp_init_crypto(it, fd, config->features);
 361                 if (error >= 0)
 362                         syslog(LOG_INFO, "%s: SSL initialization successful",
 363                                 it->queueid);
 364                 else
 365                         goto out;
 366         }
 367 #endif /* HAVE_CRYPTO */
 368
 369         send_remote_command(fd, "EHLO %s", hostname());
 370         if (read_remote(fd, 0, NULL) != 2) {
 371                 syslog(LOG_WARNING, "%s: remote delivery deferred: "
 372                        " EHLO failed: %s", it->queueid, neterr);
 373                 asprintf(errmsgc, "%s did not like our EHLO:\n%s",
 374                     host, neterr);
 375                 return (-1);
 376         }
 377
 378         /*
 379          * Use SMTP authentication if the user defined an entry for the remote
 380          * or smarthost
 381          */
 382         SLIST_FOREACH(a, &authusers, next) {
 383                 if (strcmp(a->host, host) == 0) {
 384                         do_auth = 1;
 385                         break;
 386                 }
 387         }
 388
 389         if (do_auth == 1) {
 390                 /*
 391                  * Check if the user wants plain text login without using
 392                  * encryption.
 393                  */
 394                 syslog(LOG_INFO, "%s: Use SMTP authentication",
 395                                 it->queueid);
 396                 error = smtp_login(it, fd, a->login, a->password);
 397                 if (error < 0) {
 398                         syslog(LOG_ERR, "%s: remote delivery failed:"
 399                                         " SMTP login failed: %m", it->queueid);
 400                         asprintf(errmsgc, "SMTP login to %s failed", host);
 401                         return (-1);
 402                 }
 403                 /* SMTP login is not available, so try without */
 404                 else if (error > 0)
 405                         syslog(LOG_WARNING, "%s: SMTP login not available."
 406                                         " Try without", it->queueid);
 407         }
 408
 409 #define READ_REMOTE_CHECK(c, exp)       \
 410         res = read_remote(fd, 0, NULL); \
 411         if (res == 5) { \
 412                 syslog(LOG_ERR, "%s: remote delivery failed: " \
 413                        c " failed: %s", it->queueid, neterr); \
 414                 asprintf(errmsgc, "%s did not like our " c ":\n%s", \
 415                     host, neterr); \
 416                 return (-1); \
 417         } else if (res != exp) { \
 418                 syslog(LOG_NOTICE, "%s: remote delivery deferred: " \
 419                        c " failed: %s", it->queueid, neterr); \
 420                 return (1); \
 421         }
 422
 423         send_remote_command(fd, "MAIL FROM:<%s>", it->sender);
 424         READ_REMOTE_CHECK("MAIL FROM", 2);
 425
 426         send_remote_command(fd, "RCPT TO:<%s>", it->addr);
 427         READ_REMOTE_CHECK("RCPT TO", 2);
 428
 429         send_remote_command(fd, "DATA");
 430         READ_REMOTE_CHECK("DATA", 3);
 431
 432         if (fseek(it->queuef, it->hdrlen, SEEK_SET) != 0) {
 433                 syslog(LOG_ERR, "%s: remote delivery deferred: cannot seek: %s",
 434                        it->queueid, neterr);
 435                 return (1);
 436         }
 437
 438         error = 0;
 439         while (!feof(it->queuef)) {
 440                 if (fgets(line, sizeof(line), it->queuef) == NULL)
 441                         break;
 442                 linelen = strlen(line);
 443                 if (linelen == 0 || line[linelen - 1] != '\n') {
 444                         syslog(LOG_CRIT, "%s: remote delivery failed:"
 445                                 "corrupted queue file", it->queueid);
 446                         *errmsg = "corrupted queue file";
 447                         error = -1;
 448                         goto out;
 449                 }
 450
 451                 /* Remove trailing \n's and escape leading dots */
 452                 trim_line(line);
 453
 454                 /*
 455                  * If the first character is a dot, we escape it so the line
 456                  * length increases
 457                 */
 458                 if (line[0] == '.')
 459                         linelen++;
 460
 461                 if (send_remote_command(fd, "%s", line) != (ssize_t)linelen+1) {
 462                         syslog(LOG_NOTICE, "%s: remote delivery deferred: "
 463                                 "write error", it->queueid);
 464                         error = 1;
 465                         goto out;
 466                 }
 467         }
 468
 469         send_remote_command(fd, ".");
 470         READ_REMOTE_CHECK("final DATA", 2);
 471
 472         send_remote_command(fd, "QUIT");
 473         if (read_remote(fd, 0, NULL) != 2)
 474                 syslog(LOG_INFO, "%s: remote delivery succeeded but "
 475                        "QUIT failed: %s", it->queueid, neterr);
 476 out:
 477
 478         close(fd);
 479         return (error);
 480 }
 481