tls.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ Generic TLS / S/MIME commands.
   3  *
   4  * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
   5  * Copyright (c) 2012 - 2018 Steffen (Daode) Nurpmeso <steffen@sdaoden.eu>.
   6  * SPDX-License-Identifier: BSD-4-Clause TODO ISC (is taken from book!)
   7  */
   8 /*
   9  * Copyright (c) 2002
  10  * Gunnar Ritter.  All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  * This product includes software developed by Gunnar Ritter
  23  * and his contributors.
  24  * 4. Neither the name of Gunnar Ritter nor the names of his contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY GUNNAR RITTER AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL GUNNAR RITTER OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  */
  40 #undef n_FILE
  41 #define n_FILE tls
  42
  43 #ifndef HAVE_AMALGAMATION
  44 # include "nail.h"
  45 #endif
  46
  47 EMPTY_FILE()
  48 #ifdef HAVE_TLS
  49 struct a_tls_verify_levels{
  50    char const tv_name[8];
  51    enum n_tls_verify_level tv_level;
  52 };
  53
  54 /* Supported SSL/TLS verification methods: update manual on change! */
  55 static struct a_tls_verify_levels const a_tls_verify_levels[] = {
  56    {"strict", n_TLS_VERIFY_STRICT},
  57    {"ask", n_TLS_VERIFY_ASK},
  58    {"warn", n_TLS_VERIFY_WARN},
  59    {"ignore", n_TLS_VERIFY_IGNORE}
  60 };
  61
  62 FL void
  63 n_tls_set_verify_level(struct url const *urlp){
  64    size_t i;
  65    char const *cp;
  66    NYD2_ENTER;
  67
  68    n_tls_verify_level = n_TLS_VERIFY_ASK;
  69
  70    if((cp = xok_vlook(tls_verify, urlp, OXM_ALL)) != NULL ||
  71          (cp = xok_vlook(ssl_verify, urlp, OXM_ALL)) != NULL){
  72       for(i = 0;;)
  73          if(!asccasecmp(a_tls_verify_levels[i].tv_name, cp)){
  74             n_tls_verify_level = a_tls_verify_levels[i].tv_level;
  75             break;
  76          }else if(++i >= n_NELEM(a_tls_verify_levels)){
  77             n_err(_("Invalid value of *tls-verify*: %s\n"), cp);
  78             break;
  79          }
  80    }
  81    NYD2_LEAVE;
  82 }
  83
  84 FL bool_t
  85 n_tls_verify_decide(void){
  86    bool_t rv;
  87    NYD2_ENTER;
  88
  89    switch(n_tls_verify_level){
  90    default:
  91    case n_TLS_VERIFY_STRICT:
  92       rv = FAL0;
  93       break;
  94    case n_TLS_VERIFY_ASK:
  95       rv = getapproval(NULL, FAL0);
  96       break;
  97    case n_TLS_VERIFY_WARN:
  98    case n_TLS_VERIFY_IGNORE:
  99       rv = TRU1;
 100       break;
 101    }
 102    NYD2_LEAVE;
 103    return rv;
 104 }
 105
 106 FL enum okay
 107 smime_split(FILE *ip, FILE **hp, FILE **bp, long xcount, int keep)
 108 {
 109    struct myline {
 110       struct myline  *ml_next;
 111       size_t         ml_len;
 112       char           ml_buf[n_VFIELD_SIZE(0)];
 113    } *head, *tail;
 114    char *buf;
 115    size_t bufsize, buflen, cnt;
 116    int c;
 117    enum okay rv = STOP;
 118    NYD_ENTER;
 119
 120    if ((*hp = Ftmp(NULL, "smimeh", OF_RDWR | OF_UNLINK | OF_REGISTER)) == NULL)
 121       goto jetmp;
 122    if ((*bp = Ftmp(NULL, "smimeb", OF_RDWR | OF_UNLINK | OF_REGISTER)
 123          ) == NULL) {
 124       Fclose(*hp);
 125 jetmp:
 126       n_perr(_("tempfile"), 0);
 127       goto jleave;
 128    }
 129
 130    head = tail = NULL;
 131    buf = n_alloc(bufsize = LINESIZE);
 132    cnt = (xcount < 0) ? fsize(ip) : xcount;
 133
 134    while (fgetline(&buf, &bufsize, &cnt, &buflen, ip, 0) != NULL &&
 135          *buf != '\n') {
 136       if (!ascncasecmp(buf, "content-", 8)) {
 137          if (keep)
 138             fputs("X-Encoded-", *hp);
 139          for (;;) {
 140             struct myline *ml = n_alloc(n_VSTRUCT_SIZEOF(struct myline, ml_buf
 141                   ) + buflen +1);
 142             if (tail != NULL)
 143                tail->ml_next = ml;
 144             else
 145                head = ml;
 146             tail = ml;
 147             ml->ml_next = NULL;
 148             ml->ml_len = buflen;
 149             memcpy(ml->ml_buf, buf, buflen +1);
 150             if (keep)
 151                fwrite(buf, sizeof *buf, buflen, *hp);
 152             c = getc(ip);
 153             ungetc(c, ip);
 154             if (!blankchar(c))
 155                break;
 156             fgetline(&buf, &bufsize, &cnt, &buflen, ip, 0);
 157          }
 158          continue;
 159       }
 160       fwrite(buf, sizeof *buf, buflen, *hp);
 161    }
 162    fflush_rewind(*hp);
 163
 164    while (head != NULL) {
 165       fwrite(head->ml_buf, sizeof *head->ml_buf, head->ml_len, *bp);
 166       tail = head;
 167       head = head->ml_next;
 168       n_free(tail);
 169    }
 170    putc('\n', *bp);
 171    while (fgetline(&buf, &bufsize, &cnt, &buflen, ip, 0) != NULL)
 172       fwrite(buf, sizeof *buf, buflen, *bp);
 173    fflush_rewind(*bp);
 174
 175    n_free(buf);
 176    rv = OKAY;
 177 jleave:
 178    NYD_LEAVE;
 179    return rv;
 180 }
 181
 182 FL FILE *
 183 smime_sign_assemble(FILE *hp, FILE *bp, FILE *sp, char const *message_digest)
 184 {
 185    char *boundary;
 186    int c, lastc = EOF;
 187    FILE *op;
 188    NYD_ENTER;
 189
 190    if ((op = Ftmp(NULL, "smimea", OF_RDWR | OF_UNLINK | OF_REGISTER)
 191          ) == NULL) {
 192       n_perr(_("tempfile"), 0);
 193       goto jleave;
 194    }
 195
 196    while ((c = getc(hp)) != EOF) {
 197       if (c == '\n' && lastc == '\n')
 198          break;
 199       putc(c, op);
 200       lastc = c;
 201    }
 202
 203    boundary = mime_param_boundary_create();
 204    fprintf(op, "Content-Type: multipart/signed;\n"
 205       " protocol=\"application/pkcs7-signature\"; micalg=%s;\n"
 206       " boundary=\"%s\"\n\n", message_digest, boundary);
 207    fprintf(op, "This is a S/MIME signed message.\n\n--%s\n", boundary);
 208    while ((c = getc(bp)) != EOF)
 209       putc(c, op);
 210
 211    fprintf(op, "\n--%s\n", boundary);
 212    fputs("Content-Type: application/pkcs7-signature; name=\"smime.p7s\"\n"
 213       "Content-Transfer-Encoding: base64\n"
 214       "Content-Disposition: attachment; filename=\"smime.p7s\"\n"
 215       "Content-Description: S/MIME digital signature\n\n", op);
 216    while ((c = getc(sp)) != EOF) {
 217       if (c == '-') {
 218          while ((c = getc(sp)) != EOF && c != '\n');
 219          continue;
 220       }
 221       putc(c, op);
 222    }
 223
 224    fprintf(op, "\n--%s--\n", boundary);
 225
 226    Fclose(hp);
 227    Fclose(bp);
 228    Fclose(sp);
 229
 230    fflush(op);
 231    if (ferror(op)) {
 232       n_perr(_("signed output data"), 0);
 233       Fclose(op);
 234       op = NULL;
 235       goto jleave;
 236    }
 237    rewind(op);
 238 jleave:
 239    NYD_LEAVE;
 240    return op;
 241 }
 242
 243 FL FILE *
 244 smime_encrypt_assemble(FILE *hp, FILE *yp)
 245 {
 246    FILE *op;
 247    int c, lastc = EOF;
 248    NYD_ENTER;
 249
 250    if ((op = Ftmp(NULL, "smimee", OF_RDWR | OF_UNLINK | OF_REGISTER)
 251          ) == NULL) {
 252       n_perr(_("tempfile"), 0);
 253       goto jleave;
 254    }
 255
 256    while ((c = getc(hp)) != EOF) {
 257       if (c == '\n' && lastc == '\n')
 258          break;
 259       putc(c, op);
 260       lastc = c;
 261    }
 262
 263    fputs("Content-Type: application/pkcs7-mime; name=\"smime.p7m\"\n"
 264       "Content-Transfer-Encoding: base64\n"
 265       "Content-Disposition: attachment; filename=\"smime.p7m\"\n"
 266       "Content-Description: S/MIME encrypted message\n\n", op);
 267    while ((c = getc(yp)) != EOF) {
 268       if (c == '-') {
 269          while ((c = getc(yp)) != EOF && c != '\n');
 270          continue;
 271       }
 272       putc(c, op);
 273    }
 274
 275    Fclose(hp);
 276    Fclose(yp);
 277
 278    fflush(op);
 279    if (ferror(op)) {
 280       n_perr(_("encrypted output data"), 0);
 281       Fclose(op);
 282       op = NULL;
 283       goto jleave;
 284    }
 285    rewind(op);
 286 jleave:
 287    NYD_LEAVE;
 288    return op;
 289 }
 290
 291 FL struct message *
 292 smime_decrypt_assemble(struct message *m, FILE *hp, FILE *bp)
 293 {
 294    ui32_t lastnl = 0;
 295    int binary = 0;
 296    char *buf = NULL;
 297    size_t bufsize = 0, buflen, cnt;
 298    long lns = 0, octets = 0;
 299    struct message *x;
 300    off_t offset;
 301    NYD_ENTER;
 302
 303    x = n_autorec_alloc(sizeof *x);
 304    *x = *m;
 305    fflush(mb.mb_otf);
 306    fseek(mb.mb_otf, 0L, SEEK_END);
 307    offset = ftell(mb.mb_otf);
 308
 309    cnt = fsize(hp);
 310    while (fgetline(&buf, &bufsize, &cnt, &buflen, hp, 0) != NULL) {
 311       char const *cp;
 312       if (buf[0] == '\n')
 313          break;
 314       if ((cp = thisfield(buf, "content-transfer-encoding")) != NULL)
 315          if (!ascncasecmp(cp, "binary", 7))
 316             binary = 1;
 317       fwrite(buf, sizeof *buf, buflen, mb.mb_otf);
 318       octets += buflen;
 319       ++lns;
 320    }
 321
 322    {  struct time_current save = time_current;
 323       time_current_update(&time_current, TRU1);
 324       octets += mkdate(mb.mb_otf, "X-Decoding-Date");
 325       time_current = save;
 326    }
 327    ++lns;
 328
 329    cnt = fsize(bp);
 330    while (fgetline(&buf, &bufsize, &cnt, &buflen, bp, 0) != NULL) {
 331       lns++;
 332       if (!binary && buf[buflen - 1] == '\n' && buf[buflen - 2] == '\r')
 333          buf[--buflen - 1] = '\n';
 334       fwrite(buf, sizeof *buf, buflen, mb.mb_otf);
 335       octets += buflen;
 336       if (buf[0] == '\n')
 337          ++lastnl;
 338       else if (buf[buflen - 1] == '\n')
 339          lastnl = 1;
 340       else
 341          lastnl = 0;
 342    }
 343
 344    while (!binary && lastnl < 2) {
 345       putc('\n', mb.mb_otf);
 346       ++lns;
 347       ++octets;
 348       ++lastnl;
 349    }
 350
 351    Fclose(hp);
 352    Fclose(bp);
 353    n_free(buf);
 354
 355    fflush(mb.mb_otf);
 356    if (ferror(mb.mb_otf)) {
 357       n_perr(_("decrypted output data"), 0);
 358       x = NULL;
 359    }else{
 360       x->m_size = x->m_xsize = octets;
 361       x->m_lines = x->m_xlines = lns;
 362       x->m_block = mailx_blockof(offset);
 363       x->m_offset = mailx_offsetof(offset);
 364    }
 365    NYD_LEAVE;
 366    return x;
 367 }
 368
 369 FL int
 370 c_certsave(void *vp){
 371    FILE *fp;
 372    int *msgvec, *ip;
 373    struct n_cmd_arg_ctx *cacp;
 374    NYD_ENTER;
 375
 376    cacp = vp;
 377    assert(cacp->cac_no == 2);
 378
 379    msgvec = cacp->cac_arg->ca_arg.ca_msglist;
 380    /* C99 */{
 381       char *file, *cp;
 382
 383       file = cacp->cac_arg->ca_next->ca_arg.ca_str.s;
 384       if((cp = fexpand(file, FEXP_LOCAL_FILE | FEXP_NOPROTO)) == NULL ||
 385             *cp == '\0'){
 386          n_err(_("`certsave': file expansion failed: %s\n"),
 387             n_shexp_quote_cp(file, FAL0));
 388          vp = NULL;
 389          goto jleave;
 390       }
 391       file = cp;
 392
 393       if((fp = Fopen(file, "a")) == NULL){
 394          n_perr(file, 0);
 395          vp = NULL;
 396          goto jleave;
 397       }
 398    }
 399
 400    for(ip = msgvec; *ip != 0; ++ip)
 401       if(smime_certsave(&message[*ip - 1], *ip, fp) != OKAY)
 402          vp = NULL;
 403
 404    Fclose(fp);
 405
 406    if(vp != NULL)
 407       fprintf(n_stdout, "Certificate(s) saved\n");
 408 jleave:
 409    NYD_LEAVE;
 410    return (vp != NULL);
 411 }
 412
 413 FL bool_t
 414 n_tls_rfc2595_hostname_match(char const *host, char const *pattern){
 415    bool_t rv;
 416    NYD_ENTER;
 417
 418    if(pattern[0] == '*' && pattern[1] == '.'){
 419       ++pattern;
 420       while(*host && *host != '.')
 421          ++host;
 422    }
 423    rv = (asccasecmp(host, pattern) == 0);
 424    NYD_LEAVE;
 425    return rv;
 426 }
 427
 428 FL int
 429 c_tls(void *vp){
 430    size_t i;
 431    char const **argv, *varname, *varres, *cp;
 432    NYD_ENTER;
 433
 434    argv = vp;
 435    vp = NULL; /* -> return value (boolean) */
 436    varname = (n_pstate & n_PS_ARGMOD_VPUT) ? *argv++ : NULL;
 437    varres = n_empty;
 438
 439    if((cp = argv[0])[0] == '\0')
 440       goto jesubcmd;
 441    else if(is_asccaseprefix(cp, "fingerprint")){
 442 #ifndef HAVE_SOCKETS
 443       n_err(_("`tls': fingerprint: no +sockets in *features*\n"));
 444       n_pstate_err_no = n_ERR_OPNOTSUPP;
 445       goto jleave;
 446 #else
 447       struct sock so;
 448       struct url url;
 449
 450       if(argv[1] == NULL || argv[2] != NULL)
 451          goto jesynopsis;
 452       if((i = strlen(*++argv)) >= UI32_MAX)
 453          goto jeoverflow; /* TODO generic for ALL commands!! */
 454       if(!url_parse(&url, CPROTO_CERTINFO, *argv))
 455          goto jeinval;
 456       if(!sopen(&so, &url)){ /* auto-closes for CPROTO_CERTINFO on success */
 457          n_pstate_err_no = n_err_no;
 458          goto jleave;
 459       }
 460       if(so.s_tls_finger == NULL)
 461          goto jeinval;
 462       varres = so.s_tls_finger;
 463 #endif /* HAVE_SOCKETS */
 464    }else
 465       goto jesubcmd;
 466
 467    n_pstate_err_no = n_ERR_NONE;
 468    vp = (char*)-1;
 469 jleave:
 470    if(varname == NULL){
 471       if(fprintf(n_stdout, "%s\n", varres) < 0){
 472          n_pstate_err_no = n_err_no;
 473          vp = NULL;
 474       }
 475    }else if(!n_var_vset(varname, (uintptr_t)varres)){
 476       n_pstate_err_no = n_ERR_NOTSUP;
 477       vp = NULL;
 478    }
 479    NYD_LEAVE;
 480    return (vp == NULL);
 481
 482 jeoverflow:
 483    n_err(_("`tls': string length or offset overflows datatype\n"));
 484    n_pstate_err_no = n_ERR_OVERFLOW;
 485    goto jleave;
 486
 487 jesubcmd:
 488    n_err(_("`tls': invalid subcommand: %s\n"),
 489       n_shexp_quote_cp(*argv, FAL0));
 490 jesynopsis:
 491    n_err(_("Synopsis: tls: <command> [<:argument:>]\n"));
 492 jeinval:
 493    n_pstate_err_no = n_ERR_INVAL;
 494    goto jleave;
 495 }
 496 #endif /* HAVE_TLS */
 497
 498 /* s-it-mode */