smtp.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ SMTP client and other internet related functions.
   3  *
   4  * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
   5  * Copyright (c) 2012 - 2013 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 #ifdef HAVE_MD5
  59 # include "md5.h"
  60 #endif
  61
  62 static char             *smtpbuf;
  63 static size_t           smtpbufsize;
  64 static sigjmp_buf       smtpjmp;
  65
  66 static void     onterm(int signo);
  67 static int      read_smtp(struct sock *sp, int val, int ign_eof);
  68 static int      talk_smtp(struct name *to, FILE *fi, struct sock *sp,
  69                         char *server, char *uhp, struct header *hp,
  70                         const char *user, const char *password,
  71                         const char *skinned);
  72
  73 static void
  74 onterm(int signo)
  75 {
  76         (void)signo;
  77         siglongjmp(smtpjmp, 1);
  78 }
  79
  80 /*
  81  * Get the SMTP server's answer, expecting val.
  82  */
  83 static int
  84 read_smtp(struct sock *sp, int val, int ign_eof)
  85 {
  86         int ret;
  87         int len;
  88
  89         do {
  90                 if ((len = sgetline(&smtpbuf, &smtpbufsize, NULL, sp)) < 6) {
  91                         if (len >= 0 && !ign_eof)
  92                                 fprintf(stderr, tr(241,
  93                                         "Unexpected EOF on SMTP connection\n"));
  94                         return -1;
  95                 }
  96                 if (options & OPT_VERBOSE)
  97                         fputs(smtpbuf, stderr);
  98                 switch (*smtpbuf) {
  99                 case '1': ret = 1; break;
 100                 case '2': ret = 2; break;
 101                 case '3': ret = 3; break;
 102                 case '4': ret = 4; break;
 103                 default: ret = 5;
 104                 }
 105                 if (val != ret)
 106                         fprintf(stderr, tr(191, "smtp-server: %s"), smtpbuf);
 107         } while (smtpbuf[3] == '-');
 108         return ret;
 109 }
 110
 111 /*
 112  * Macros for talk_smtp.
 113  */
 114 #define _SMTP_ANSWER(x, ign_eof)        \
 115                         if ((options & OPT_DEBUG) == 0) { \
 116                                 int     y; \
 117                                 if ((y = read_smtp(sp, x, ign_eof)) != (x) && \
 118                                         (!(ign_eof) || y != -1)) { \
 119                                         if (b != NULL) \
 120                                                 free(b); \
 121                                         return 1; \
 122                                 } \
 123                         }
 124
 125 #define SMTP_ANSWER(x)  _SMTP_ANSWER(x, 0)
 126
 127 #define SMTP_OUT(x)     if (options & OPT_VERBOSE) \
 128                                 fprintf(stderr, ">>> %s", x); \
 129                         if ((options & OPT_DEBUG) == 0) \
 130                                 swrite(sp, x);
 131
 132 /*
 133  * Talk to a SMTP server.
 134  */
 135 static int
 136 talk_smtp(struct name *to, FILE *fi, struct sock *sp,
 137                 char *xserver, char *uhp, struct header *hp,
 138                 const char *user, const char *password, const char *skinned)
 139 {
 140         char o[LINESIZE], *authstr, *cp, *b = NULL;
 141         struct str b64;
 142         struct name *n;
 143         size_t blen, cnt, bsize = 0;
 144         enum { AUTH_NONE, AUTH_PLAIN, AUTH_LOGIN, AUTH_CRAM_MD5 } auth;
 145         int inhdr = 1, inbcc = 0;
 146         (void)hp;
 147         (void)xserver;
 148         (void)uhp;
 149
 150         if ((authstr = smtp_auth_var("", skinned)) == NULL)
 151                 auth = user && password ? AUTH_LOGIN : AUTH_NONE;
 152         else if (strcmp(authstr, "plain") == 0)
 153                 auth = AUTH_PLAIN;
 154         else if (strcmp(authstr, "login") == 0)
 155                 auth = AUTH_LOGIN;
 156         else if (strcmp(authstr, "cram-md5") == 0) {
 157 #ifdef HAVE_MD5
 158                 auth = AUTH_CRAM_MD5;
 159 #else
 160                 fprintf(stderr, tr(277, "No CRAM-MD5 support compiled in.\n"));
 161                 return (1);
 162 #endif
 163         } else {
 164                 fprintf(stderr, tr(274,
 165                         "Unknown SMTP authentication method: %s\n"), authstr);
 166                 return 1;
 167         }
 168         if (auth != AUTH_NONE && (user == NULL || password == NULL)) {
 169                 fprintf(stderr, tr(275,
 170                         "User and password are necessary "
 171                         "for SMTP authentication.\n"));
 172                 return 1;
 173         }
 174         SMTP_ANSWER(2);
 175 #ifdef HAVE_SSL
 176         if (! sp->s_use_ssl && value("smtp-use-starttls")) {
 177                 char *server;
 178                 if ((cp = strchr(xserver, ':')) != NULL) {
 179                         server = salloc(cp - xserver + 1);
 180                         memcpy(server, xserver, cp - xserver);
 181                         server[cp - xserver] = '\0';
 182                 } else
 183                         server = xserver;
 184                 snprintf(o, sizeof o, "EHLO %s\r\n", nodename(1));
 185                 SMTP_OUT(o);
 186                 SMTP_ANSWER(2);
 187                 SMTP_OUT("STARTTLS\r\n");
 188                 SMTP_ANSWER(2);
 189                 if ((options & OPT_DEBUG) == 0 &&
 190                                 ssl_open(server, sp, uhp) != OKAY)
 191                         return 1;
 192         }
 193 #else
 194         if (value("smtp-use-starttls")) {
 195                 fprintf(stderr, tr(225, "No SSL support compiled in.\n"));
 196                 return 1;
 197         }
 198 #endif
 199         if (auth != AUTH_NONE) {
 200                 snprintf(o, sizeof o, "EHLO %s\r\n", nodename(1));
 201                 SMTP_OUT(o);
 202                 SMTP_ANSWER(2);
 203                 switch (auth) {
 204                 case AUTH_NONE:
 205 #ifndef HAVE_MD5
 206                 case AUTH_CRAM_MD5:
 207 #endif
 208                         /* FALLTRHU
 209                          * Won't happen, but gcc(1) and clang(1) whine without
 210                          * and Coverity whines with; that's a hard one.. */
 211                 case AUTH_LOGIN:
 212                         SMTP_OUT("AUTH LOGIN\r\n");
 213                         SMTP_ANSWER(3);
 214                         (void)b64_encode_cp(&b64, user, B64_SALLOC|B64_CRLF);
 215                         SMTP_OUT(b64.s);
 216                         SMTP_ANSWER(3);
 217                         (void)b64_encode_cp(&b64, password,
 218                                 B64_SALLOC|B64_CRLF);
 219                         SMTP_OUT(b64.s);
 220                         SMTP_ANSWER(2);
 221                         break;
 222                 case AUTH_PLAIN:
 223                         SMTP_OUT("AUTH PLAIN\r\n");
 224                         SMTP_ANSWER(3);
 225                         (void)snprintf(o, sizeof o, "%c%s%c%s",
 226                                 '\0', user, '\0', password);
 227                         (void)b64_encode_buf(&b64, o, strlen(user) +
 228                                 strlen(password) + 2, B64_SALLOC|B64_CRLF);
 229                         SMTP_OUT(b64.s);
 230                         SMTP_ANSWER(2);
 231                         break;
 232 #ifdef HAVE_MD5
 233                 case AUTH_CRAM_MD5:
 234                         SMTP_OUT("AUTH CRAM-MD5\r\n");
 235                         SMTP_ANSWER(3);
 236                         for (cp = smtpbuf; digitchar(*cp); ++cp)
 237                                 ;
 238                         while (blankchar(*cp))
 239                                 ++cp;
 240                         cp = cram_md5_string(user, password, cp);
 241                         SMTP_OUT(cp);
 242                         SMTP_ANSWER(2);
 243                         break;
 244 #endif
 245                 }
 246         } else {
 247                 snprintf(o, sizeof o, "HELO %s\r\n", nodename(1));
 248                 SMTP_OUT(o);
 249                 SMTP_ANSWER(2);
 250         }
 251         snprintf(o, sizeof o, "MAIL FROM:<%s>\r\n", skinned);
 252         SMTP_OUT(o);
 253         SMTP_ANSWER(2);
 254         for (n = to; n != NULL; n = n->n_flink) {
 255                 if ((n->n_type & GDEL) == 0) {
 256                         snprintf(o, sizeof o, "RCPT TO:<%s>\r\n",
 257                                 skinned_name(n));
 258                         SMTP_OUT(o);
 259                         SMTP_ANSWER(2);
 260                 }
 261         }
 262         SMTP_OUT("DATA\r\n");
 263         SMTP_ANSWER(3);
 264         fflush(fi);
 265         rewind(fi);
 266         cnt = fsize(fi);
 267         while (fgetline(&b, &bsize, &cnt, &blen, fi, 1) != NULL) {
 268                 if (inhdr) {
 269                         if (*b == '\n') {
 270                                 inhdr = 0;
 271                                 inbcc = 0;
 272                         } else if (inbcc && blankchar(*b & 0377))
 273                                 continue;
 274                         /*
 275                          * We know what we have generated first, so
 276                          * do not look for whitespace before the ':'.
 277                          */
 278                         else if (ascncasecmp(b, "bcc: ", 5) == 0) {
 279                                 inbcc = 1;
 280                                 continue;
 281                         } else
 282                                 inbcc = 0;
 283                 }
 284                 if (*b == '.') {
 285                         if (options & OPT_DEBUG)
 286                                 putc('.', stderr);
 287                         else
 288                                 swrite1(sp, ".", 1, 1);
 289                 }
 290                 if (options & OPT_DEBUG) {
 291                         fprintf(stderr, ">>> %s", b);
 292                         continue;
 293                 }
 294                 b[blen-1] = '\r';
 295                 b[blen] = '\n';
 296                 swrite1(sp, b, blen+1, 1);
 297         }
 298         SMTP_OUT(".\r\n");
 299         SMTP_ANSWER(2);
 300         SMTP_OUT("QUIT\r\n");
 301         _SMTP_ANSWER(2, 1);
 302         if (b != NULL)
 303                 free(b);
 304         return 0;
 305 }
 306
 307 FL char *
 308 smtp_auth_var(char const *atype, char const *addr)
 309 {
 310         size_t tl, al, len;
 311         char *var, *cp;
 312
 313         tl = strlen(atype);
 314         al = strlen(addr);
 315         len = tl + al + 10 + 1;
 316         var = ac_alloc(len);
 317
 318         /* Try a 'user@host', i.e., address specific version first */
 319         (void)snprintf(var, len, "smtp-auth%s-%s", atype, addr);
 320         if ((cp = value(var)) == NULL) {
 321                 snprintf(var, len, "smtp-auth%s", atype);
 322                 cp = value(var);
 323         }
 324         if (cp != NULL)
 325                 cp = savestr(cp);
 326
 327         ac_free(var);
 328         return cp;
 329 }
 330
 331 /*
 332  * Connect to a SMTP server.
 333  */
 334 FL int
 335 smtp_mta(char *volatile server, struct name *volatile to, FILE *fi,
 336                 struct header *hp, const char *user, const char *password,
 337                 const char *skinned)
 338 {
 339         struct sock     so;
 340         int     use_ssl, ret;
 341         sighandler_type volatile saveterm;
 342
 343         memset(&so, 0, sizeof so);
 344         saveterm = safe_signal(SIGTERM, SIG_IGN);
 345         if (sigsetjmp(smtpjmp, 1)) {
 346                 safe_signal(SIGTERM, saveterm);
 347                 return 1;
 348         }
 349         if (saveterm != SIG_IGN)
 350                 safe_signal(SIGTERM, onterm);
 351         if (strncmp(server, "smtp://", 7) == 0) {
 352                 use_ssl = 0;
 353                 server += 7;
 354 #ifdef HAVE_SSL
 355         } else if (strncmp(server, "smtps://", 8) == 0) {
 356                 use_ssl = 1;
 357                 server += 8;
 358 #endif
 359         } else
 360                 use_ssl = 0;
 361         if ((options & OPT_DEBUG) == 0 && sopen(server, &so, use_ssl, server,
 362                         use_ssl ? "smtps" : "smtp",
 363                         (options & OPT_VERBOSE) != 0) != OKAY) {
 364                 safe_signal(SIGTERM, saveterm);
 365                 return 1;
 366         }
 367         so.s_desc = "SMTP";
 368         ret = talk_smtp(to, fi, &so, server, server, hp,
 369                         user, password, skinned);
 370         if ((options & OPT_DEBUG) == 0)
 371                 sclose(&so);
 372         if (smtpbuf) {
 373                 free(smtpbuf);
 374                 smtpbuf = NULL;
 375                 smtpbufsize = 0;
 376         }
 377         safe_signal(SIGTERM, saveterm);
 378         return ret;
 379 }
 380 #endif /* HAVE_SMTP */