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 bool_t  _smtp_talk(struct sock *sp, struct sendbundle *sbp);
  80
  81 #ifdef HAVE_GSSAPI
  82 static bool_t  _smtp_gssapi(struct sock *sp, struct sendbundle *sbp,
  83                   struct smtp_line *slp);
  84 #endif
  85
  86 static void
  87 _smtp_onterm(int signo)
  88 {
  89    NYD_X; /* Signal handler */
  90    UNUSED(signo);
  91    siglongjmp(_smtp_jmp, 1);
  92 }
  93
  94 static int
  95 _smtp_read(struct sock *sp, struct smtp_line *slp, int val,
  96    bool_t ign_eof, bool_t want_dat)
  97 {
  98    int rv, len;
  99    char *cp;
 100    NYD_ENTER;
 101
 102    do {
 103       if ((len = sgetline(&slp->buf, &slp->bufsize, NULL, sp)) < 6) {
 104          if (len >= 0 && !ign_eof)
 105             fprintf(stderr, _("Unexpected EOF on SMTP connection\n"));
 106             rv = -1;
 107             goto jleave;
 108       }
 109       if (options & OPT_VERBVERB)
 110          fputs(slp->buf, stderr);
 111       switch (slp->buf[0]) {
 112       case '1':   rv = 1; break;
 113       case '2':   rv = 2; break;
 114       case '3':   rv = 3; break;
 115       case '4':   rv = 4; break;
 116       default:    rv = 5; break;
 117       }
 118       if (val != rv)
 119          fprintf(stderr, _("smtp-server: %s"), slp->buf);
 120    } while (slp->buf[3] == '-');
 121
 122    if (want_dat) {
 123       for (cp = slp->buf; digitchar(*cp); --len, ++cp)
 124          ;
 125       for (; blankchar(*cp); --len, ++cp)
 126          ;
 127       slp->dat = cp;
 128       assert(len >= 2);
 129       len -= 2;
 130       cp[slp->datlen = (size_t)len] = '\0';
 131    }
 132 jleave:
 133    NYD_LEAVE;
 134    return rv;
 135 }
 136
 137 /* Indirect SMTP I/O */
 138 #define _ANSWER(X, IGNEOF, WANTDAT) \
 139 do if (!(options & OPT_DEBUG)) {\
 140    int y;\
 141    if ((y = _smtp_read(sp, slp, X, IGNEOF, WANTDAT)) != (X) &&\
 142          (!(IGNEOF) || y != -1))\
 143       goto jleave;\
 144 } while (0)
 145 #define _OUT(X) \
 146 do {\
 147    if (options & OPT_VERBVERB)\
 148       fprintf(stderr, ">>> %s", X);\
 149    if (!(options & OPT_DEBUG))\
 150       swrite(sp, X);\
 151 } while (0)
 152
 153 static bool_t
 154 _smtp_talk(struct sock *sp, struct sendbundle *sbp)
 155 {
 156    char o[LINESIZE], *hostname;
 157    struct smtp_line _sl, *slp = &_sl;
 158    struct str b64;
 159    struct name *n;
 160    size_t blen, cnt;
 161    bool_t inhdr = TRU1, inbcc = FAL0, rv = FAL0;
 162    NYD_ENTER;
 163
 164    hostname = nodename(TRU1);
 165    slp->buf = NULL;
 166    slp->bufsize = 0;
 167
 168    /* Read greeting */
 169    _ANSWER(2, FAL0, FAL0);
 170
 171 #ifdef HAVE_SSL
 172    if (!sp->s_use_ssl && xok_blook(smtp_use_starttls, &sbp->sb_url, OXM_ALL)) {
 173       snprintf(o, sizeof o, LINE("EHLO %s"), hostname);
 174       _OUT(o);
 175       _ANSWER(2, FAL0, FAL0);
 176
 177       _OUT(LINE("STARTTLS"));
 178       _ANSWER(2, FAL0, FAL0);
 179
 180       if (!(options & OPT_DEBUG) &&
 181             ssl_open(sbp->sb_url.url_host.s, sp, sbp->sb_url.url_u_h_p.s
 182                ) != OKAY)
 183          goto jleave;
 184    }
 185 #else
 186    if (xok_blook(smtp_use_starttls, &sbp->sb_url, OXM_ALL)) {
 187       fprintf(stderr, _("No SSL support compiled in.\n"));
 188       goto jleave;
 189    }
 190 #endif
 191
 192    /* Shorthand: no authentication, plain HELO? */
 193    if (sbp->sb_ccred.cc_authtype == AUTHTYPE_NONE) {
 194       snprintf(o, sizeof o, LINE("HELO %s"), hostname);
 195       _OUT(o);
 196       _ANSWER(2, FAL0, FAL0);
 197       goto jsend;
 198    }
 199
 200    /* We'll have to deal with authentication */
 201    snprintf(o, sizeof o, LINE("EHLO %s"), hostname);
 202    _OUT(o);
 203    _ANSWER(2, FAL0, FAL0);
 204
 205    switch (sbp->sb_ccred.cc_authtype) {
 206    default:
 207       /* FALLTHRU (doesn't happen) */
 208    case AUTHTYPE_PLAIN:
 209       _OUT(LINE("AUTH PLAIN"));
 210       _ANSWER(3, FAL0, FAL0);
 211
 212       snprintf(o, sizeof o, "%c%s%c%s",
 213          '\0', sbp->sb_ccred.cc_user.s, '\0', sbp->sb_ccred.cc_pass.s);
 214       b64_encode_buf(&b64, o,
 215          sbp->sb_ccred.cc_user.l + sbp->sb_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, sbp->sb_ccred.cc_user.s, B64_SALLOC | B64_CRLF);
 225       _OUT(b64.s);
 226       _ANSWER(3, FAL0, FAL0);
 227
 228       b64_encode_cp(&b64, sbp->sb_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       {  char *cp = cram_md5_string(&sbp->sb_ccred.cc_user,
 237                &sbp->sb_ccred.cc_pass, slp->dat);
 238          _OUT(cp);
 239       }
 240       _ANSWER(2, FAL0, FAL0);
 241       break;
 242 #endif
 243 #ifdef HAVE_GSSAPI
 244    case AUTHTYPE_GSSAPI:
 245       if (!_smtp_gssapi(sp, sbp, slp))
 246          goto jleave;
 247       break;
 248 #endif
 249    }
 250
 251 jsend:
 252    snprintf(o, sizeof o, LINE("MAIL FROM:<%s>"), sbp->sb_url.url_u_h.s);
 253    _OUT(o);
 254    _ANSWER(2, FAL0, FAL0);
 255
 256    for (n = sbp->sb_to; n != NULL; n = n->n_flink) {
 257       if (!(n->n_type & GDEL)) {
 258          snprintf(o, sizeof o, LINE("RCPT TO:<%s>"), skinned_name(n));
 259          _OUT(o);
 260          _ANSWER(2, FAL0, FAL0);
 261       }
 262    }
 263
 264    _OUT(LINE("DATA"));
 265    _ANSWER(3, FAL0, FAL0);
 266
 267    fflush_rewind(sbp->sb_input);
 268    cnt = fsize(sbp->sb_input);
 269    while (fgetline(&slp->buf, &slp->bufsize, &cnt, &blen, sbp->sb_input, 1)
 270          != NULL) {
 271       if (inhdr) {
 272          if (*slp->buf == '\n')
 273             inhdr = inbcc = FAL0;
 274          else if (inbcc && blankchar(*slp->buf))
 275             continue;
 276          /* We know what we have generated first, so do not look for whitespace
 277           * before the ':' */
 278          else if (!ascncasecmp(slp->buf, "bcc: ", 5)) {
 279             inbcc = TRU1;
 280             continue;
 281          } else
 282             inbcc = FAL0;
 283       }
 284
 285       if (*slp->buf == '.') {
 286          if (options & OPT_DEBUG)
 287             putc('.', stderr);
 288          else
 289             swrite1(sp, ".", 1, 1);
 290       }
 291       if (options & OPT_DEBUG) {
 292          fprintf(stderr, ">>> %s", slp->buf);
 293          continue;
 294       }
 295       slp->buf[blen - 1] = NL[0];
 296       slp->buf[blen] = NL[1];
 297       swrite1(sp, slp->buf, blen + 1, 1);
 298    }
 299    _OUT(LINE("."));
 300    _ANSWER(2, FAL0, FAL0);
 301
 302    _OUT(LINE("QUIT"));
 303    _ANSWER(2, TRU1, FAL0);
 304    rv = TRU1;
 305 jleave:
 306    if (slp->buf != NULL)
 307       free(slp->buf);
 308    NYD_LEAVE;
 309    return rv;
 310 }
 311
 312 #ifdef HAVE_GSSAPI
 313 # include "smtp_gssapi.h"
 314 #endif
 315
 316 #undef _OUT
 317 #undef _ANSWER
 318
 319 FL bool_t
 320 smtp_mta(struct sendbundle *sbp)
 321 {
 322    struct sock so;
 323    sighandler_type volatile saveterm;
 324    bool_t volatile rv = FAL0;
 325    NYD_ENTER;
 326
 327    saveterm = safe_signal(SIGTERM, SIG_IGN);
 328    if (sigsetjmp(_smtp_jmp, 1))
 329       goto jleave;
 330    if (saveterm != SIG_IGN)
 331       safe_signal(SIGTERM, &_smtp_onterm);
 332
 333    memset(&so, 0, sizeof so);
 334    if (!(options & OPT_DEBUG) && !sopen(&so, &sbp->sb_url))
 335       goto jleave;
 336
 337    so.s_desc = "SMTP";
 338    rv = _smtp_talk(&so, sbp);
 339
 340    if (!(options & OPT_DEBUG))
 341       sclose(&so);
 342 jleave:
 343    safe_signal(SIGTERM, saveterm);
 344    NYD_LEAVE;
 345    return rv;
 346 }
 347
 348 #undef LINE
 349 #undef NL
 350 #endif /* HAVE_SMTP */
 351
 352 /* s-it-mode */