smtp.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ SMTP client.
   3  *
   4  * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
   5  * Copyright (c) 2012 - 2014 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   6  */
   7 /*
   8  * Copyright (c) 2000
   9  * Gunnar Ritter.  All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *    This product includes software developed by Gunnar Ritter
  22  *    and his contributors.
  23  * 4. Neither the name of Gunnar Ritter nor the names of his contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY GUNNAR RITTER AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL GUNNAR RITTER OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  */
  39
  40 #ifndef HAVE_AMALGAMATION
  41 # include "nail.h"
  42 #endif
  43
  44 EMPTY_FILE(smtp)
  45 #ifdef HAVE_SMTP
  46 #ifdef HAVE_SOCKETS
  47 # include <sys/socket.h>
  48
  49 # include <netdb.h>
  50
  51 # include <netinet/in.h>
  52
  53 # ifdef HAVE_ARPA_INET_H
  54 #  include <arpa/inet.h>
  55 # endif
  56 #endif
  57
  58 #undef NL
  59 #undef LINE
  60 #define NL        "\015\012"
  61 #define LINE(X)   X NL
  62
  63 static sigjmp_buf _smtp_jmp;
  64
  65 static void _smtp_onterm(int signo);
  66
  67 /* Get the SMTP server's answer, expecting val */
  68 static int  _smtp_read(struct sock *sp, char **buf, size_t *bufsize, int val,
  69                int ign_eof);
  70
  71 /* Talk to a SMTP server */
  72 static int  _smtp_talk(struct name *to, FILE *fi, struct sock *sp,
  73                char *server, char *uhp, struct header *hp, char const *user,
  74                char const *password, char const *skinned);
  75
  76 static void
  77 _smtp_onterm(int signo)
  78 {
  79    NYD_X; /* Signal handler */
  80    UNUSED(signo);
  81    siglongjmp(_smtp_jmp, 1);
  82 }
  83
  84 static int
  85 _smtp_read(struct sock *sp, char **buf, size_t *bufsize, int val, int ign_eof)
  86 {
  87    int rv, len;
  88    NYD_ENTER;
  89
  90    do {
  91       if ((len = sgetline(buf, bufsize, NULL, sp)) < 6) {
  92          if (len >= 0 && !ign_eof)
  93             fprintf(stderr, tr(241, "Unexpected EOF on SMTP connection\n"));
  94             rv = -1;
  95             goto jleave;
  96       }
  97       if (options & OPT_VERBOSE)
  98          fputs(*buf, stderr);
  99       switch (**buf) {
 100       case '1':   rv = 1; break;
 101       case '2':   rv = 2; break;
 102       case '3':   rv = 3; break;
 103       case '4':   rv = 4; break;
 104       default:    rv = 5; break;
 105       }
 106       if (val != rv)
 107          fprintf(stderr, tr(191, "smtp-server: %s"), *buf);
 108    } while ((*buf)[3] == '-');
 109 jleave:
 110    NYD_LEAVE;
 111    return rv;
 112 }
 113
 114 static int
 115 _smtp_talk(struct name *to, FILE *fi, struct sock *sp, char *xserver,
 116    char *uhp, struct header *hp, char const *user, char const *password,
 117    char const *skinned)
 118 {
 119 #define _ANSWER(X, IGNEOF) \
 120 do if (!(options & OPT_DEBUG)) {\
 121    int y;\
 122    if ((y = _smtp_read(sp, &buf, &bsize, X, IGNEOF)) != (X) &&\
 123          (!(IGNEOF) || y != -1))\
 124       goto jleave;\
 125 } while (0)
 126 #define _OUT(X) \
 127 do {\
 128    if (options & OPT_VERBOSE)\
 129       fprintf(stderr, ">>> %s", X);\
 130    if (!(options & OPT_DEBUG))\
 131       swrite(sp, X);\
 132 } while (0)
 133
 134    char o[LINESIZE], *authstr, *cp, *buf = NULL;
 135    struct str b64;
 136    struct name *n;
 137    size_t blen, cnt, bsize = 0;
 138    enum {AUTH_NONE, AUTH_PLAIN, AUTH_LOGIN, AUTH_CRAM_MD5} auth;
 139    int inhdr = 1, inbcc = 0, rv = 1;
 140    NYD_ENTER;
 141    UNUSED(hp);
 142    UNUSED(xserver);
 143    UNUSED(uhp);
 144
 145    if ((authstr = smtp_auth_var("", skinned)) == NULL)
 146       auth = (user != NULL && password != NULL) ? AUTH_LOGIN : AUTH_NONE;
 147    else if (!strcmp(authstr, "plain"))
 148       auth = AUTH_PLAIN;
 149    else if (!strcmp(authstr, "login"))
 150       auth = AUTH_LOGIN;
 151    else if (!strcmp(authstr, "cram-md5")) {
 152 #ifdef HAVE_MD5
 153       auth = AUTH_CRAM_MD5;
 154 #else
 155       fprintf(stderr, tr(277, "No CRAM-MD5 support compiled in.\n"));
 156       goto jleave;
 157 #endif
 158    } else {
 159       fprintf(stderr, tr(274, "Unknown SMTP authentication method: %s\n"),
 160          authstr);
 161       goto jleave;
 162    }
 163
 164    if (auth != AUTH_NONE && (user == NULL || password == NULL)) {
 165       fprintf(stderr, tr(275,
 166          "User and password are necessary for SMTP authentication.\n"));
 167       goto jleave;
 168    }
 169    _ANSWER(2, 0);
 170
 171 #ifdef HAVE_SSL
 172    if (!sp->s_use_ssl && ok_blook(smtp_use_starttls)) {
 173       char *server;
 174
 175       if ((cp = strchr(xserver, ':')) != NULL)
 176          server = savestrbuf(xserver, PTR2SIZE(cp - xserver));
 177       else
 178          server = xserver;
 179       snprintf(o, sizeof o, LINE("EHLO %s"), nodename(1));
 180       _OUT(o);
 181       _ANSWER(2, 0);
 182
 183       _OUT(LINE("STARTTLS"));
 184       _ANSWER(2, 0);
 185
 186       if ((options & OPT_DEBUG) == 0 && ssl_open(server, sp, uhp) != OKAY)
 187          goto jleave;
 188    }
 189 #else
 190    if (ok_blook(smtp_use_starttls)) {
 191       fprintf(stderr, tr(225, "No SSL support compiled in.\n"));
 192       goto jleave;
 193    }
 194 #endif
 195
 196    if (auth != AUTH_NONE) {
 197       snprintf(o, sizeof o, LINE("EHLO %s"), nodename(1));
 198       _OUT(o);
 199       _ANSWER(2, 0);
 200
 201       switch (auth) {
 202       case AUTH_NONE:
 203 #ifndef HAVE_MD5
 204       case AUTH_CRAM_MD5:
 205 #endif
 206          /* FALLTRHU
 207           * Won't happen, but gcc(1) and clang(1) whine without
 208           * and Coverity whines with; that's a hard one.. */
 209       case AUTH_LOGIN:
 210          _OUT(LINE("AUTH LOGIN"));
 211          _ANSWER(3, 0);
 212
 213          b64_encode_cp(&b64, user, B64_SALLOC | B64_CRLF);
 214          _OUT(b64.s);
 215          _ANSWER(3, 0);
 216
 217          b64_encode_cp(&b64, password, B64_SALLOC | B64_CRLF);
 218          _OUT(b64.s);
 219          _ANSWER(2, 0);
 220          break;
 221       case AUTH_PLAIN:
 222          _OUT(LINE("AUTH PLAIN"));
 223          _ANSWER(3, 0);
 224
 225          snprintf(o, sizeof o, "%c%s%c%s", '\0', user, '\0', password);
 226          b64_encode_buf(&b64, o, strlen(user) + strlen(password) + 2,
 227             B64_SALLOC | B64_CRLF);
 228          _OUT(b64.s);
 229          _ANSWER(2, 0);
 230          break;
 231 #ifdef HAVE_MD5
 232       case AUTH_CRAM_MD5:
 233          _OUT(LINE("AUTH CRAM-MD5"));
 234          _ANSWER(3, 0);
 235
 236          for (cp = buf; digitchar(*cp); ++cp)
 237             ;
 238          while (blankchar(*cp))
 239             ++cp;
 240          cp = cram_md5_string(user, password, cp);
 241          _OUT(cp);
 242          _ANSWER(2, 0);
 243          break;
 244 #endif
 245       }
 246    } else {
 247       snprintf(o, sizeof o, LINE("HELO %s"), nodename(1));
 248       _OUT(o);
 249       _ANSWER(2, 0);
 250    }
 251
 252    snprintf(o, sizeof o, LINE("MAIL FROM:<%s>"), skinned);
 253    _OUT(o);
 254    _ANSWER(2, 0);
 255
 256    for (n = 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, 0);
 261       }
 262    }
 263
 264    _OUT(LINE("DATA"));
 265    _ANSWER(3, 0);
 266    fflush_rewind(fi);
 267
 268    cnt = fsize(fi);
 269    while (fgetline(&buf, &bsize, &cnt, &blen, fi, 1) != NULL) {
 270       if (inhdr) {
 271          if (*buf == '\n') {
 272             inhdr = 0;
 273             inbcc = 0;
 274          } else if (inbcc && blankchar(*buf))
 275             continue;
 276          /* We know what we have generated first, so do not look for whitespace
 277           * before the ':' */
 278          else if (!ascncasecmp(buf, "bcc: ", 5)) {
 279             inbcc = 1;
 280             continue;
 281          } else
 282             inbcc = 0;
 283       }
 284
 285       if (*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", buf);
 293          continue;
 294       }
 295       buf[blen - 1] = NL[0];
 296       buf[blen] = NL[1];
 297       swrite1(sp, buf, blen + 1, 1);
 298    }
 299    _OUT(LINE("."));
 300    _ANSWER(2, 0);
 301
 302    _OUT(LINE("QUIT"));
 303    _ANSWER(2, 1);
 304    rv = 0;
 305 jleave:
 306    if (buf != NULL)
 307       free(buf);
 308    NYD_LEAVE;
 309    return rv;
 310 #undef _OUT
 311 #undef _ANSWER
 312 #undef __ANSWER
 313 }
 314
 315 FL char *
 316 smtp_auth_var(char const *atype, char const *addr) /* FIXME GENERIC */
 317 {
 318    size_t tl, al, len;
 319    char *var, *cp;
 320    NYD_ENTER;
 321
 322    tl = strlen(atype);
 323    al = strlen(addr);
 324    len = tl + al + 10 +1;
 325    var = ac_alloc(len);
 326
 327    /* Try a 'user@host', i.e., address specific version first */
 328    (void)snprintf(var, len, "smtp-auth%s-%s", atype, addr);
 329    if ((cp = vok_vlook(var)) == NULL) {
 330       snprintf(var, len, "smtp-auth%s", atype);
 331       cp = vok_vlook(var);
 332    }
 333    if (cp != NULL)
 334       cp = savestr(cp);
 335
 336    ac_free(var);
 337    NYD_LEAVE;
 338    return cp;
 339 }
 340
 341 FL int
 342 smtp_mta(char *volatile server, struct name *volatile to, FILE *fi,
 343    struct header *hp, char const *user, char const *password,
 344    char const *skinned)
 345 {
 346    struct sock so;
 347    sighandler_type volatile saveterm;
 348    int use_ssl, rv = 1;
 349    NYD_ENTER;
 350
 351    memset(&so, 0, sizeof so);
 352
 353    saveterm = safe_signal(SIGTERM, SIG_IGN);
 354    if (sigsetjmp(_smtp_jmp, 1))
 355       goto jleave;
 356    if (saveterm != SIG_IGN)
 357       safe_signal(SIGTERM, &_smtp_onterm);
 358
 359    if (!strncmp(server, "smtp://", 7)) {
 360       use_ssl = 0;
 361       server += 7;
 362 #ifdef HAVE_SSL
 363    } else if (!strncmp(server, "smtps://", 8)) {
 364       use_ssl = 1;
 365       server += 8;
 366 #endif
 367    } else
 368       use_ssl = 0;
 369
 370    if (!(options & OPT_DEBUG) && sopen(server, &so, use_ssl, server,
 371          (use_ssl ? "smtps" : "smtp")) != OKAY)
 372       goto jleave;
 373
 374    so.s_desc = "SMTP";
 375    rv = _smtp_talk(to, fi, &so, server, server, hp, user, password, skinned);
 376
 377    if (!(options & OPT_DEBUG))
 378       sclose(&so);
 379 jleave:
 380    safe_signal(SIGTERM, saveterm);
 381    NYD_LEAVE;
 382    return rv;
 383 }
 384
 385 #undef LINE
 386 #undef NL
 387 #endif /* HAVE_SMTP */
 388
 389 /* vim:set fenc=utf-8:s-it-mode */