smtp.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ SMTP client.
   3  *@ TODO - use initial responses to save a round-trip (RFC 4954)
   4  *@ TODO - more (verbose) understanding+rection upon STATUS CODES
   5  *
   6  * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
   7  * Copyright (c) 2012 - 2014 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   8  */
   9 /*
  10  * Copyright (c) 2000
  11  * Gunnar Ritter.  All rights reserved.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. All advertising materials mentioning features or use of this software
  22  *    must display the following acknowledgement:
  23  *    This product includes software developed by Gunnar Ritter
  24  *    and his contributors.
  25  * 4. Neither the name of Gunnar Ritter nor the names of his contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY GUNNAR RITTER AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL GUNNAR RITTER OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40  */
  41
  42 #ifndef HAVE_AMALGAMATION
  43 # include "nail.h"
  44 #endif
  45
  46 EMPTY_FILE(smtp)
  47 #ifdef HAVE_SMTP
  48 #include <sys/socket.h>
  49
  50 #include <netdb.h>
  51
  52 #include <netinet/in.h>
  53
  54 #ifdef HAVE_ARPA_INET_H
  55 # include <arpa/inet.h>
  56 #endif
  57
  58 #undef NL
  59 #undef LINE
  60 #define NL        "\015\012"
  61 #define LINE(X)   X NL
  62
  63 struct smtp_line {
  64    char     *dat;    /* Actual data */
  65    size_t   datlen;
  66    char     *buf;    /* Memory buffer */
  67    size_t   bufsize;
  68 };
  69
  70 static sigjmp_buf _smtp_jmp;
  71
  72 static void    _smtp_onterm(int signo);
  73
  74 /* Get the SMTP server's answer, expecting val */
  75 static int     _smtp_read(struct sock *sp, struct smtp_line *slp, int val,
  76                   bool_t ign_eof, bool_t want_dat);
  77
  78 /* Talk to a SMTP server */
  79 static int     _smtp_talk(struct name *to, struct header *hp, FILE *fi,
  80                   struct sock *sp, struct url *urlp, struct ccred *ccred);
  81
  82 #ifdef HAVE_GSSAPI
  83 static bool_t  _smtp_gssapi(struct sock *sp, struct url *urlp,
  84                   struct ccred *ccred, struct smtp_line *slp);
  85 #endif
  86
  87 static void
  88 _smtp_onterm(int signo)
  89 {
  90    NYD_X; /* Signal handler */
  91    UNUSED(signo);
  92    siglongjmp(_smtp_jmp, 1);
  93 }
  94
  95 static int
  96 _smtp_read(struct sock *sp, struct smtp_line *slp, int val,
  97    bool_t ign_eof, bool_t want_dat)
  98 {
  99    int rv, len;
 100    char *cp;
 101    NYD_ENTER;
 102
 103    do {
 104       if ((len = sgetline(&slp->buf, &slp->bufsize, NULL, sp)) < 6) {
 105          if (len >= 0 && !ign_eof)
 106             fprintf(stderr, tr(241, "Unexpected EOF on SMTP connection\n"));
 107             rv = -1;
 108             goto jleave;
 109       }
 110       if (options & OPT_VERBOSE)
 111          fputs(slp->buf, stderr);
 112       switch (slp->buf[0]) {
 113       case '1':   rv = 1; break;
 114       case '2':   rv = 2; break;
 115       case '3':   rv = 3; break;
 116       case '4':   rv = 4; break;
 117       default:    rv = 5; break;
 118       }
 119       if (val != rv)
 120          fprintf(stderr, tr(191, "smtp-server: %s"), slp->buf);
 121    } while (slp->buf[3] == '-');
 122
 123    if (want_dat) {
 124       for (cp = slp->buf; digitchar(*cp); --len, ++cp)
 125          ;
 126       for (; blankchar(*cp); --len, ++cp)
 127          ;
 128       slp->dat = cp;
 129       assert(len >= 2);
 130       len -= 2;
 131       cp[slp->datlen = (size_t)len] = '\0';
 132    }
 133 jleave:
 134    NYD_LEAVE;
 135    return rv;
 136 }
 137
 138 /* Indirect SMTP I/O */
 139 #define _ANSWER(X, IGNEOF, WANTDAT) \
 140 do if (!(options & OPT_DEBUG)) {\
 141    int y;\
 142    if ((y = _smtp_read(sp, slp, X, IGNEOF, WANTDAT)) != (X) &&\
 143          (!(IGNEOF) || y != -1))\
 144       goto jleave;\
 145 } while (0)
 146 #define _OUT(X) \
 147 do {\
 148    if (options & OPT_VERBOSE)\
 149       fprintf(stderr, ">>> %s", X);\
 150    if (!(options & OPT_DEBUG))\
 151       swrite(sp, X);\
 152 } while (0)
 153
 154 static int
 155 _smtp_talk(struct name *to, struct header *hp, FILE *fi, struct sock *sp,
 156    struct url *urlp, struct ccred *ccred)
 157 {
 158    char o[LINESIZE], *cp;
 159    struct smtp_line _sl, *slp = &_sl;
 160    struct str b64;
 161    struct name *n;
 162    size_t blen, cnt;
 163    int inhdr = 1, inbcc = 0, rv = 1;
 164    NYD_ENTER;
 165    UNUSED(hp);
 166
 167    slp->buf = NULL;
 168    slp->bufsize = 0;
 169
 170    /* Read greeting */
 171    _ANSWER(2, FAL0, FAL0);
 172
 173 #ifdef HAVE_SSL
 174    if (!sp->s_use_ssl && ok_blook(smtp_use_starttls)) {
 175       snprintf(o, sizeof o, LINE("EHLO %s"), nodename(1));
 176       _OUT(o);
 177       _ANSWER(2, FAL0, FAL0);
 178
 179       _OUT(LINE("STARTTLS"));
 180       _ANSWER(2, FAL0, FAL0);
 181
 182       if (!(options & OPT_DEBUG) &&
 183             ssl_open(urlp->url_host.s, sp, urlp->url_uhp.s) != OKAY)
 184          goto jleave;
 185    }
 186 #else
 187    if (ok_blook(smtp_use_starttls)) {
 188       fprintf(stderr, tr(225, "No SSL support compiled in.\n"));
 189       goto jleave;
 190    }
 191 #endif
 192
 193    /* Shorthand: no authentication, plain HELO? */
 194    if (ccred->cc_authtype == AUTHTYPE_NONE) {
 195       snprintf(o, sizeof o, LINE("HELO %s"), nodename(1));
 196       _OUT(o);
 197       _ANSWER(2, FAL0, FAL0);
 198       goto jsend;
 199    }
 200
 201    /* We'll have to deal with authentication */
 202    snprintf(o, sizeof o, LINE("EHLO %s"), nodename(1));
 203    _OUT(o);
 204    _ANSWER(2, FAL0, FAL0);
 205
 206    switch (ccred->cc_authtype) {
 207    default:
 208       /* FALLTHRU (doesn't happen) */
 209    case AUTHTYPE_PLAIN:
 210       _OUT(LINE("AUTH PLAIN"));
 211       _ANSWER(3, FAL0, FAL0);
 212
 213       snprintf(o, sizeof o, "%c%s%c%s",
 214          '\0', ccred->cc_user.s, '\0', ccred->cc_pass.s);
 215       b64_encode_buf(&b64, o, ccred->cc_user.l + ccred->cc_pass.l + 2,
 216          B64_SALLOC | B64_CRLF);
 217       _OUT(b64.s);
 218       _ANSWER(2, FAL0, FAL0);
 219       break;
 220    case AUTHTYPE_LOGIN:
 221       _OUT(LINE("AUTH LOGIN"));
 222       _ANSWER(3, FAL0, FAL0);
 223
 224       b64_encode_cp(&b64, ccred->cc_user.s, B64_SALLOC | B64_CRLF);
 225       _OUT(b64.s);
 226       _ANSWER(3, FAL0, FAL0);
 227
 228       b64_encode_cp(&b64, ccred->cc_pass.s, B64_SALLOC | B64_CRLF);
 229       _OUT(b64.s);
 230       _ANSWER(2, FAL0, FAL0);
 231       break;
 232 #ifdef HAVE_MD5
 233    case AUTHTYPE_CRAM_MD5:
 234       _OUT(LINE("AUTH CRAM-MD5"));
 235       _ANSWER(3, FAL0, TRU1);
 236       cp = cram_md5_string(ccred->cc_user.s, ccred->cc_pass.s, slp->dat);
 237       _OUT(cp);
 238       _ANSWER(2, FAL0, FAL0);
 239       break;
 240 #endif
 241 #ifdef HAVE_GSSAPI
 242    case AUTHTYPE_GSSAPI:
 243       if (!_smtp_gssapi(sp, urlp, ccred, slp))
 244          goto jleave;
 245       break;
 246 #endif
 247    }
 248
 249 jsend:
 250    snprintf(o, sizeof o, LINE("MAIL FROM:<%s>"), urlp->url_uh.s);
 251    _OUT(o);
 252    _ANSWER(2, FAL0, FAL0);
 253
 254    for (n = to; n != NULL; n = n->n_flink) {
 255       if (!(n->n_type & GDEL)) {
 256          snprintf(o, sizeof o, LINE("RCPT TO:<%s>"), skinned_name(n));
 257          _OUT(o);
 258          _ANSWER(2, FAL0, FAL0);
 259       }
 260    }
 261
 262    _OUT(LINE("DATA"));
 263    _ANSWER(3, FAL0, FAL0);
 264
 265    fflush_rewind(fi);
 266    cnt = fsize(fi);
 267    while (fgetline(&slp->buf, &slp->bufsize, &cnt, &blen, fi, 1) != NULL) {
 268       if (inhdr) {
 269          if (*slp->buf == '\n') {
 270             inhdr = 0;
 271             inbcc = 0;
 272          } else if (inbcc && blankchar(*slp->buf))
 273             continue;
 274          /* We know what we have generated first, so do not look for whitespace
 275           * before the ':' */
 276          else if (!ascncasecmp(slp->buf, "bcc: ", 5)) {
 277             inbcc = 1;
 278             continue;
 279          } else
 280             inbcc = 0;
 281       }
 282
 283       if (*slp->buf == '.') {
 284          if (options & OPT_DEBUG)
 285             putc('.', stderr);
 286          else
 287             swrite1(sp, ".", 1, 1);
 288       }
 289       if (options & OPT_DEBUG) {
 290          fprintf(stderr, ">>> %s", slp->buf);
 291          continue;
 292       }
 293       slp->buf[blen - 1] = NL[0];
 294       slp->buf[blen] = NL[1];
 295       swrite1(sp, slp->buf, blen + 1, 1);
 296    }
 297    _OUT(LINE("."));
 298    _ANSWER(2, FAL0, FAL0);
 299
 300    _OUT(LINE("QUIT"));
 301    _ANSWER(2, TRU1, FAL0);
 302    rv = 0;
 303 jleave:
 304    if (slp->buf != NULL)
 305       free(slp->buf);
 306    NYD_LEAVE;
 307    return rv;
 308 }
 309
 310 #ifdef HAVE_GSSAPI
 311 # include "smtp_gssapi.h"
 312 #endif
 313
 314 #undef _OUT
 315 #undef _ANSWER
 316
 317 FL int
 318 smtp_mta(struct url *urlp, struct name * volatile to, FILE *fi,
 319    struct header *hp, struct ccred *ccred)
 320 {
 321    struct sock so;
 322    sighandler_type volatile saveterm;
 323    int rv = 1;
 324    NYD_ENTER;
 325
 326    saveterm = safe_signal(SIGTERM, SIG_IGN);
 327    if (sigsetjmp(_smtp_jmp, 1))
 328       goto jleave;
 329    if (saveterm != SIG_IGN)
 330       safe_signal(SIGTERM, &_smtp_onterm);
 331
 332    memset(&so, 0, sizeof so);
 333    if (!(options & OPT_DEBUG) && sopen(&so, urlp) != OKAY)
 334       goto jleave;
 335
 336    so.s_desc = "SMTP";
 337    rv = _smtp_talk(to, hp, fi, &so, urlp, ccred);
 338
 339    if (!(options & OPT_DEBUG))
 340       sclose(&so);
 341 jleave:
 342    safe_signal(SIGTERM, saveterm);
 343    NYD_LEAVE;
 344    return rv;
 345 }
 346
 347 #undef LINE
 348 #undef NL
 349 #endif /* HAVE_SMTP */
 350
 351 /* vim:set fenc=utf-8:s-it-mode */