src/src/pdkim/pdkim.c

   1 /*
   2  *  PDKIM - a RFC4871 (DKIM) implementation
   3  *
   4  *  Copyright (C) 2009 - 2015  Tom Kistner <tom@duncanthrax.net>
   5  *
   6  *  http://duncanthrax.net/pdkim/
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License along
  19  *  with this program; if not, write to the Free Software Foundation, Inc.,
  20  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #include "../exim.h"
  24 #include "pdkim.h"
  25 #include "pdkim-rsa.h"
  26
  27 #include "polarssl/sha1.h"
  28 #include "polarssl/sha2.h"
  29 #include "polarssl/rsa.h"
  30 #include "polarssl/base64.h"
  31
  32 #define PDKIM_SIGNATURE_VERSION     "1"
  33 #define PDKIM_PUB_RECORD_VERSION    "DKIM1"
  34
  35 #define PDKIM_MAX_HEADER_LEN        65536
  36 #define PDKIM_MAX_HEADERS           512
  37 #define PDKIM_MAX_BODY_LINE_LEN     16384
  38 #define PDKIM_DNS_TXT_MAX_NAMELEN   1024
  39 #define PDKIM_DEFAULT_SIGN_HEADERS "From:Sender:Reply-To:Subject:Date:"\
  40                              "Message-ID:To:Cc:MIME-Version:Content-Type:"\
  41                              "Content-Transfer-Encoding:Content-ID:"\
  42                              "Content-Description:Resent-Date:Resent-From:"\
  43                              "Resent-Sender:Resent-To:Resent-Cc:"\
  44                              "Resent-Message-ID:In-Reply-To:References:"\
  45                              "List-Id:List-Help:List-Unsubscribe:"\
  46                              "List-Subscribe:List-Post:List-Owner:List-Archive"
  47
  48 /* -------------------------------------------------------------------------- */
  49 struct pdkim_stringlist {
  50   char *value;
  51   int  tag;
  52   void *next;
  53 };
  54
  55 #define PDKIM_STR_ALLOC_FRAG 256
  56 struct pdkim_str {
  57   char         *str;
  58   unsigned int  len;
  59   unsigned int  allocated;
  60 };
  61
  62 /* -------------------------------------------------------------------------- */
  63 /* A bunch of list constants */
  64 const char *pdkim_querymethods[] = {
  65   "dns/txt",
  66   NULL
  67 };
  68 const char *pdkim_algos[] = {
  69   "rsa-sha256",
  70   "rsa-sha1",
  71   NULL
  72 };
  73 const char *pdkim_canons[] = {
  74   "simple",
  75   "relaxed",
  76   NULL
  77 };
  78 const char *pdkim_hashes[] = {
  79   "sha256",
  80   "sha1",
  81   NULL
  82 };
  83 const char *pdkim_keytypes[] = {
  84   "rsa",
  85   NULL
  86 };
  87
  88 typedef struct pdkim_combined_canon_entry {
  89   const char *str;
  90   int canon_headers;
  91   int canon_body;
  92 } pdkim_combined_canon_entry;
  93 pdkim_combined_canon_entry pdkim_combined_canons[] = {
  94   { "simple/simple",    PDKIM_CANON_SIMPLE,   PDKIM_CANON_SIMPLE },
  95   { "simple/relaxed",   PDKIM_CANON_SIMPLE,   PDKIM_CANON_RELAXED },
  96   { "relaxed/simple",   PDKIM_CANON_RELAXED,  PDKIM_CANON_SIMPLE },
  97   { "relaxed/relaxed",  PDKIM_CANON_RELAXED,  PDKIM_CANON_RELAXED },
  98   { "simple",           PDKIM_CANON_SIMPLE,   PDKIM_CANON_SIMPLE },
  99   { "relaxed",          PDKIM_CANON_RELAXED,  PDKIM_CANON_SIMPLE },
 100   { NULL,               0,                    0 }
 101 };
 102
 103
 104 const char *pdkim_verify_status_str(int status) {
 105   switch(status) {
 106     case PDKIM_VERIFY_NONE:    return "PDKIM_VERIFY_NONE";
 107     case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID";
 108     case PDKIM_VERIFY_FAIL:    return "PDKIM_VERIFY_FAIL";
 109     case PDKIM_VERIFY_PASS:    return "PDKIM_VERIFY_PASS";
 110     default:                   return "PDKIM_VERIFY_UNKNOWN";
 111   }
 112 }
 113 const char *pdkim_verify_ext_status_str(int ext_status) {
 114   switch(ext_status) {
 115     case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY";
 116     case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE";
 117     case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE";
 118     case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE";
 119     case PDKIM_VERIFY_INVALID_PUBKEY_PARSING: return "PDKIM_VERIFY_INVALID_PUBKEY_PARSING";
 120     default: return "PDKIM_VERIFY_UNKNOWN";
 121   }
 122 }
 123
 124
 125 /* -------------------------------------------------------------------------- */
 126 /* Print debugging functions */
 127 void
 128 pdkim_quoteprint(const char *data, int len, int lf)
 129 {
 130 int i;
 131 const unsigned char *p = (const unsigned char *)data;
 132
 133 for (i = 0; i < len; i++)
 134   {
 135   const int c = p[i];
 136   switch (c)
 137     {
 138     case ' ' : debug_printf("{SP}"); break;
 139     case '\t': debug_printf("{TB}"); break;
 140     case '\r': debug_printf("{CR}"); break;
 141     case '\n': debug_printf("{LF}"); break;
 142     case '{' : debug_printf("{BO}"); break;
 143     case '}' : debug_printf("{BC}"); break;
 144     default:
 145       if ( (c < 32) || (c > 127) )
 146         debug_printf("{%02x}", c);
 147       else
 148         debug_printf("%c", c);
 149       break;
 150     }
 151   }
 152 if (lf)
 153   debug_printf("\n");
 154 }
 155
 156 void
 157 pdkim_hexprint(const char *data, int len, int lf)
 158 {
 159 int i;
 160 const unsigned char *p = (const unsigned char *)data;
 161
 162 for (i = 0 ; i < len; i++)
 163   debug_printf("%02x", p[i]);
 164 if (lf)
 165   debug_printf("\n");
 166 }
 167
 168
 169 /* -------------------------------------------------------------------------- */
 170 /* Simple string list implementation for convinience */
 171 pdkim_stringlist *
 172 pdkim_append_stringlist(pdkim_stringlist *base, char *str)
 173 {
 174 pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
 175
 176 if (!new_entry) return NULL;
 177 memset(new_entry, 0, sizeof(pdkim_stringlist));
 178 if (!(new_entry->value = strdup(str))) return NULL;
 179 if (base)
 180   {
 181   pdkim_stringlist *last = base;
 182   while (last->next != NULL) { last = last->next; }
 183   last->next = new_entry;
 184   return base;
 185   }
 186 else
 187   return new_entry;
 188 }
 189
 190 pdkim_stringlist *
 191 pdkim_prepend_stringlist(pdkim_stringlist *base, char *str)
 192 {
 193 pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
 194
 195 if (!new_entry) return NULL;
 196 memset(new_entry, 0, sizeof(pdkim_stringlist));
 197 if (!(new_entry->value = strdup(str))) return NULL;
 198 if (base)
 199   new_entry->next = base;
 200 return new_entry;
 201 }
 202
 203
 204 /* -------------------------------------------------------------------------- */
 205 /* A small "growing string" implementation to escape malloc/realloc hell */
 206
 207 pdkim_str *
 208 pdkim_strnew (const char *cstr)
 209 {
 210 unsigned int len = cstr ? strlen(cstr) : 0;
 211 pdkim_str *p = malloc(sizeof(pdkim_str));
 212
 213 if (!p) return NULL;
 214 memset(p, 0, sizeof(pdkim_str));
 215 if (!(p->str = malloc(len+1)))
 216   {
 217   free(p);
 218   return NULL;
 219   }
 220 p->allocated = len+1;
 221 p->len = len;
 222 if (cstr)
 223   strcpy(p->str, cstr);
 224 else
 225   p->str[p->len] = '\0';
 226 return p;
 227 }
 228
 229 char *
 230 pdkim_strncat(pdkim_str *str, const char *data, int len)
 231 {
 232 if ((str->allocated - str->len) < (len+1))
 233   {
 234   /* Extend the buffer */
 235   int num_frags = ((len+1)/PDKIM_STR_ALLOC_FRAG)+1;
 236   char *n = realloc(str->str,
 237                     (str->allocated+(num_frags*PDKIM_STR_ALLOC_FRAG)));
 238   if (n == NULL) return NULL;
 239   str->str = n;
 240   str->allocated += (num_frags*PDKIM_STR_ALLOC_FRAG);
 241   }
 242 strncpy(&(str->str[str->len]), data, len);
 243 str->len += len;
 244 str->str[str->len] = '\0';
 245 return str->str;
 246 }
 247
 248 char *
 249 pdkim_strcat(pdkim_str *str, const char *cstr)
 250 {
 251 return pdkim_strncat(str, cstr, strlen(cstr));
 252 }
 253
 254 char *
 255 pdkim_numcat(pdkim_str *str, unsigned long num)
 256 {
 257 char minibuf[20];
 258 snprintf(minibuf, 20, "%lu", num);
 259 return pdkim_strcat(str, minibuf);
 260 }
 261
 262 char *
 263 pdkim_strtrim(pdkim_str *str)
 264 {
 265 char *p = str->str;
 266 char *q = str->str;
 267 while ( (*p != '\0') && ((*p == '\t') || (*p == ' ')) ) p++;
 268 while (*p != '\0') {*q = *p; q++; p++;}
 269 *q = '\0';
 270 while ( (q != str->str) && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) )
 271   {
 272   *q = '\0';
 273   q--;
 274   }
 275 str->len = strlen(str->str);
 276 return str->str;
 277 }
 278
 279 char *
 280 pdkim_strclear(pdkim_str *str)
 281 {
 282 str->str[0] = '\0';
 283 str->len = 0;
 284 return str->str;
 285 }
 286
 287 void
 288 pdkim_strfree(pdkim_str *str)
 289 {
 290 if (!str) return;
 291 if (str->str) free(str->str);
 292 free(str);
 293 }
 294
 295
 296
 297 /* -------------------------------------------------------------------------- */
 298
 299 void
 300 pdkim_free_pubkey(pdkim_pubkey *pub)
 301 {
 302 if (pub)
 303   {
 304   if (pub->version    ) free(pub->version);
 305   if (pub->granularity) free(pub->granularity);
 306   if (pub->hashes     ) free(pub->hashes);
 307   if (pub->keytype    ) free(pub->keytype);
 308   if (pub->srvtype    ) free(pub->srvtype);
 309   if (pub->notes      ) free(pub->notes);
 310   if (pub->key        ) free(pub->key);
 311   free(pub);
 312   }
 313 }
 314
 315
 316 /* -------------------------------------------------------------------------- */
 317
 318 void
 319 pdkim_free_sig(pdkim_signature *sig)
 320 {
 321 if (sig)
 322   {
 323   pdkim_signature *next = (pdkim_signature *)sig->next;
 324
 325   pdkim_stringlist *e = sig->headers;
 326   while(e)
 327     {
 328     pdkim_stringlist *c = e;
 329     if (e->value) free(e->value);
 330     e = e->next;
 331     free(c);
 332     }
 333
 334   if (sig->sigdata         ) free(sig->sigdata);
 335   if (sig->bodyhash        ) free(sig->bodyhash);
 336   if (sig->selector        ) free(sig->selector);
 337   if (sig->domain          ) free(sig->domain);
 338   if (sig->identity        ) free(sig->identity);
 339   if (sig->headernames     ) free(sig->headernames);
 340   if (sig->copiedheaders   ) free(sig->copiedheaders);
 341   if (sig->rsa_privkey     ) free(sig->rsa_privkey);
 342   if (sig->sign_headers    ) free(sig->sign_headers);
 343   if (sig->signature_header) free(sig->signature_header);
 344   if (sig->sha1_body       ) free(sig->sha1_body);
 345   if (sig->sha2_body       ) free(sig->sha2_body);
 346
 347   if (sig->pubkey) pdkim_free_pubkey(sig->pubkey);
 348
 349   free(sig);
 350   if (next) pdkim_free_sig(next);
 351   }
 352 }
 353
 354
 355 /* -------------------------------------------------------------------------- */
 356
 357 DLLEXPORT void
 358 pdkim_free_ctx(pdkim_ctx *ctx)
 359 {
 360 if (ctx)
 361   {
 362   pdkim_stringlist *e = ctx->headers;
 363   while(e)
 364     {
 365     pdkim_stringlist *c = e;
 366     if (e->value) free(e->value);
 367     e = e->next;
 368     free(c);
 369     }
 370   pdkim_free_sig(ctx->sig);
 371   pdkim_strfree(ctx->cur_header);
 372   free(ctx);
 373   }
 374 }
 375
 376
 377 /* -------------------------------------------------------------------------- */
 378 /* Matches the name of the passed raw "header" against
 379    the passed colon-separated "list", starting at entry
 380    "start". Returns the position of the header name in
 381    the list. */
 382
 383 int
 384 header_name_match(const char *header,
 385                       char       *tick,
 386                       int         do_tick)
 387 {
 388 char *hname;
 389 char *lcopy;
 390 char *p;
 391 char *q;
 392 int rc = PDKIM_FAIL;
 393
 394 /* Get header name */
 395 char *hcolon = strchr(header, ':');
 396
 397 if (!hcolon) return rc; /* This isn't a header */
 398
 399 if (!(hname = malloc((hcolon-header)+1)))
 400   return PDKIM_ERR_OOM;
 401 memset(hname, 0, (hcolon-header)+1);
 402 strncpy(hname, header, (hcolon-header));
 403
 404 /* Copy tick-off list locally, so we can punch zeroes into it */
 405 if (!(lcopy = strdup(tick)))
 406   {
 407   free(hname);
 408   return PDKIM_ERR_OOM;
 409   }
 410 p = lcopy;
 411 q = strchr(p, ':');
 412 while (q)
 413   {
 414   *q = '\0';
 415
 416   if (strcasecmp(p, hname) == 0)
 417     {
 418     rc = PDKIM_OK;
 419     /* Invalidate header name instance in tick-off list */
 420     if (do_tick) tick[p-lcopy] = '_';
 421     goto BAIL;
 422     }
 423
 424   p = q+1;
 425   q = strchr(p, ':');
 426   }
 427
 428 if (strcasecmp(p, hname) == 0)
 429   {
 430   rc = PDKIM_OK;
 431   /* Invalidate header name instance in tick-off list */
 432   if (do_tick) tick[p-lcopy] = '_';
 433   }
 434
 435 BAIL:
 436 free(hname);
 437 free(lcopy);
 438 return rc;
 439 }
 440
 441
 442 /* -------------------------------------------------------------------------- */
 443 /* Performs "relaxed" canonicalization of a header. The returned pointer needs
 444    to be free()d. */
 445
 446 char *
 447 pdkim_relax_header (char *header, int crlf)
 448 {
 449 BOOL past_field_name = FALSE;
 450 BOOL seen_wsp = FALSE;
 451 char *p;
 452 char *q;
 453 char *relaxed = malloc(strlen(header)+3);
 454
 455 if (!relaxed) return NULL;
 456
 457 q = relaxed;
 458 for (p = header; *p != '\0'; p++)
 459   {
 460   int c = *p;
 461   /* Ignore CR & LF */
 462   if (c == '\r' || c == '\n')
 463     continue;
 464   if (c == '\t' || c == ' ')
 465     {
 466     if (seen_wsp)
 467       continue;
 468     c = ' ';                    /* Turns WSP into SP */
 469     seen_wsp = TRUE;
 470     }
 471   else
 472     if (!past_field_name && c == ':')
 473       {
 474       if (seen_wsp) q--;        /* This removes WSP before the colon */
 475       seen_wsp = TRUE;          /* This removes WSP after the colon */
 476       past_field_name = TRUE;
 477       }
 478     else
 479       seen_wsp = FALSE;
 480
 481   /* Lowercase header name */
 482   if (!past_field_name) c = tolower(c);
 483   *q++ = c;
 484   }
 485
 486 if (q > relaxed && q[-1] == ' ') q--; /* Squash eventual trailing SP */
 487 *q = '\0';
 488
 489 if (crlf) strcat(relaxed, "\r\n");
 490 return relaxed;
 491 }
 492
 493
 494 /* -------------------------------------------------------------------------- */
 495 #define PDKIM_QP_ERROR_DECODE -1
 496
 497 char *
 498 pdkim_decode_qp_char(char *qp_p, int *c)
 499 {
 500 char *initial_pos = qp_p;
 501
 502 /* Advance one char */
 503 qp_p++;
 504
 505 /* Check for two hex digits and decode them */
 506 if (isxdigit(*qp_p) && isxdigit(qp_p[1]))
 507   {
 508   /* Do hex conversion */
 509   *c = (isdigit(*qp_p) ? *qp_p - '0' : toupper(*qp_p) - 'A' + 10) << 4;
 510   *c != isdigit(qp_p[1]) ? qp_p[1] - '0' : toupper(qp_p[1]) - 'A' + 10;
 511   return qp_p + 2;
 512   }
 513
 514 /* Illegal char here */
 515 *c = PDKIM_QP_ERROR_DECODE;
 516 return initial_pos;
 517 }
 518
 519
 520 /* -------------------------------------------------------------------------- */
 521
 522 char *
 523 pdkim_decode_qp(char *str)
 524 {
 525 int nchar = 0;
 526 char *q;
 527 char *p = str;
 528 char *n = malloc(strlen(p)+1);
 529
 530 if (!n) return NULL;
 531
 532 *n = '\0';
 533 q = n;
 534 while (*p != '\0')
 535   {
 536   if (*p == '=')
 537     {
 538     p = pdkim_decode_qp_char(p, &nchar);
 539     if (nchar >= 0)
 540       {
 541       *q++ = nchar;
 542       continue;
 543       }
 544     }
 545   else
 546     *q++ = *p;
 547   p++;
 548   }
 549 *q = '\0';
 550 return n;
 551 }
 552
 553
 554 /* -------------------------------------------------------------------------- */
 555
 556 char *
 557 pdkim_decode_base64(char *str, int *num_decoded)
 558 {
 559 int dlen = 0;
 560 char *res;
 561
 562 base64_decode(NULL, &dlen, (unsigned char *)str, strlen(str));
 563
 564 if (!(res = malloc(dlen+1)))
 565    return NULL;
 566 if (base64_decode((unsigned char *)res, &dlen, (unsigned char *)str, strlen(str)) != 0)
 567   {
 568   free(res);
 569   return NULL;
 570   }
 571
 572 if (num_decoded) *num_decoded = dlen;
 573 return res;
 574 }
 575
 576
 577 /* -------------------------------------------------------------------------- */
 578
 579 char *
 580 pdkim_encode_base64(char *str, int num)
 581 {
 582 int dlen = 0;
 583 char *res;
 584
 585 base64_encode(NULL, &dlen, (unsigned char *)str, num);
 586
 587 if (!(res = malloc(dlen+1)))
 588   return NULL;
 589 if (base64_encode((unsigned char *)res, &dlen, (unsigned char *)str, num) != 0)
 590   {
 591   free(res);
 592   return NULL;
 593   }
 594 return res;
 595 }
 596
 597
 598 /* -------------------------------------------------------------------------- */
 599 #define PDKIM_HDR_LIMBO 0
 600 #define PDKIM_HDR_TAG   1
 601 #define PDKIM_HDR_VALUE 2
 602
 603 pdkim_signature *
 604 pdkim_parse_sig_header(pdkim_ctx *ctx, char *raw_hdr)
 605 {
 606 pdkim_signature *sig ;
 607 char *p, *q;
 608 pdkim_str *cur_tag = NULL;
 609 pdkim_str *cur_val = NULL;
 610 BOOL past_hname = FALSE;
 611 BOOL in_b_val = FALSE;
 612 int where = PDKIM_HDR_LIMBO;
 613 int i;
 614
 615 if (!(sig = malloc(sizeof(pdkim_signature)))) return NULL;
 616 memset(sig, 0, sizeof(pdkim_signature));
 617 sig->bodylength = -1;
 618
 619 if (!(sig->rawsig_no_b_val = malloc(strlen(raw_hdr)+1)))
 620   {
 621   free(sig);
 622   return NULL;
 623   }
 624
 625 q = sig->rawsig_no_b_val;
 626
 627 for (p = raw_hdr; ; p++)
 628   {
 629   char c = *p;
 630
 631   /* Ignore FWS */
 632   if (c == '\r' || c == '\n')
 633     goto NEXT_CHAR;
 634
 635   /* Fast-forward through header name */
 636   if (!past_hname)
 637     {
 638     if (c == ':') past_hname = TRUE;
 639     goto NEXT_CHAR;
 640     }
 641
 642   if (where == PDKIM_HDR_LIMBO)
 643     {
 644     /* In limbo, just wait for a tag-char to appear */
 645     if (!(c >= 'a' && c <= 'z'))
 646       goto NEXT_CHAR;
 647
 648     where = PDKIM_HDR_TAG;
 649     }
 650
 651   if (where == PDKIM_HDR_TAG)
 652     {
 653     if (!cur_tag)
 654       cur_tag = pdkim_strnew(NULL);
 655
 656     if (c >= 'a' && c <= 'z')
 657       pdkim_strncat(cur_tag, p, 1);
 658
 659     if (c == '=')
 660       {
 661       if (strcmp(cur_tag->str, "b") == 0)
 662         {
 663         *q = '='; q++;
 664         in_b_val = TRUE;
 665         }
 666       where = PDKIM_HDR_VALUE;
 667       goto NEXT_CHAR;
 668       }
 669     }
 670
 671   if (where == PDKIM_HDR_VALUE)
 672     {
 673     if (!cur_val)
 674       cur_val = pdkim_strnew(NULL);
 675
 676     if (c == '\r' || c == '\n' || c == ' ' || c == '\t')
 677       goto NEXT_CHAR;
 678
 679     if (c == ';' || c == '\0')
 680       {
 681       if (cur_tag->len > 0)
 682         {
 683         pdkim_strtrim(cur_val);
 684
 685         DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag->str, cur_val->str);
 686
 687         switch (cur_tag->str[0])
 688           {
 689           case 'b':
 690             if (cur_tag->str[1] == 'h')
 691               sig->bodyhash = pdkim_decode_base64(cur_val->str,
 692                   &sig->bodyhash_len);
 693             else
 694               sig->sigdata = pdkim_decode_base64(cur_val->str,
 695                   &sig->sigdata_len);
 696             break;
 697           case 'v':
 698               /* We only support version 1, and that is currently the
 699                  only version there is. */
 700             if (strcmp(cur_val->str, PDKIM_SIGNATURE_VERSION) == 0)
 701               sig->version = 1;
 702             break;
 703           case 'a':
 704             for (i = 0; pdkim_algos[i]; i++)
 705               if (strcmp(cur_val->str, pdkim_algos[i]) == 0)
 706                 {
 707                 sig->algo = i;
 708                 break;
 709                 }
 710             break;
 711           case 'c':
 712             for (i = 0; pdkim_combined_canons[i].str; i++)
 713               if (strcmp(cur_val->str, pdkim_combined_canons[i].str) == 0)
 714                 {
 715                 sig->canon_headers = pdkim_combined_canons[i].canon_headers;
 716                 sig->canon_body    = pdkim_combined_canons[i].canon_body;
 717                 break;
 718                 }
 719             break;
 720           case 'q':
 721             for (i = 0; pdkim_querymethods[i]; i++)
 722               if (strcmp(cur_val->str, pdkim_querymethods[i]) == 0)
 723                 {
 724                 sig->querymethod = i;
 725                 break;
 726                 }
 727             break;
 728           case 's':
 729             sig->selector = strdup(cur_val->str); break;
 730           case 'd':
 731             sig->domain = strdup(cur_val->str); break;
 732           case 'i':
 733             sig->identity = pdkim_decode_qp(cur_val->str); break;
 734           case 't':
 735             sig->created = strtoul(cur_val->str, NULL, 10); break;
 736           case 'x':
 737             sig->expires = strtoul(cur_val->str, NULL, 10); break;
 738           case 'l':
 739             sig->bodylength = strtol(cur_val->str, NULL, 10); break;
 740           case 'h':
 741             sig->headernames = strdup(cur_val->str); break;
 742           case 'z':
 743             sig->copiedheaders = pdkim_decode_qp(cur_val->str); break;
 744           default:
 745             DEBUG(D_acl) debug_printf(" Unknown tag encountered\n");
 746             break;
 747           }
 748         }
 749       pdkim_strclear(cur_tag);
 750       pdkim_strclear(cur_val);
 751       in_b_val = FALSE;
 752       where = PDKIM_HDR_LIMBO;
 753       }
 754     else
 755       pdkim_strncat(cur_val, p, 1);
 756     }
 757
 758 NEXT_CHAR:
 759   if (c == '\0')
 760     break;
 761
 762   if (!in_b_val)
 763     *q++ = c;
 764   }
 765
 766 /* Make sure the most important bits are there. */
 767 if (!(sig->domain      && (*(sig->domain)      != '\0') &&
 768       sig->selector    && (*(sig->selector)    != '\0') &&
 769       sig->headernames && (*(sig->headernames) != '\0') &&
 770       sig->bodyhash    &&
 771       sig->sigdata     &&
 772       sig->version))
 773   {
 774   pdkim_free_sig(sig);
 775   return NULL;
 776   }
 777
 778 *q = '\0';
 779 /* Chomp raw header. The final newline must not be added to the signature. */
 780 q--;
 781 while (q > sig->rawsig_no_b_val  && (*q == '\r' || *q == '\n'))
 782   *q = '\0'; q--;       /*XXX questionable code layout; possible bug */
 783
 784 DEBUG(D_acl)
 785   {
 786   debug_printf(
 787           "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
 788   pdkim_quoteprint(sig->rawsig_no_b_val, strlen(sig->rawsig_no_b_val), 1);
 789   debug_printf(
 790           "PDKIM >> Sig size: %4d bits\n", sig->sigdata_len*8);
 791   debug_printf(
 792           "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
 793   }
 794
 795 if (  !(sig->sha1_body = malloc(sizeof(sha1_context)))
 796    || !(sig->sha2_body = malloc(sizeof(sha2_context)))
 797    )
 798   {
 799   pdkim_free_sig(sig);
 800   return NULL;
 801   }
 802
 803 sha1_starts(sig->sha1_body);
 804 sha2_starts(sig->sha2_body, 0);
 805
 806 return sig;
 807 }
 808
 809
 810 /* -------------------------------------------------------------------------- */
 811
 812 pdkim_pubkey *
 813 pdkim_parse_pubkey_record(pdkim_ctx *ctx, char *raw_record)
 814 {
 815 pdkim_pubkey *pub;
 816 char *p;
 817 pdkim_str *cur_tag = NULL;
 818 pdkim_str *cur_val = NULL;
 819 int where = PDKIM_HDR_LIMBO;
 820
 821 if (!(pub = malloc(sizeof(pdkim_pubkey)))) return NULL;
 822 memset(pub, 0, sizeof(pdkim_pubkey));
 823
 824 for (p = raw_record; ; p++)
 825   {
 826   char c = *p;
 827
 828   /* Ignore FWS */
 829   if (c == '\r' || c == '\n')
 830     goto NEXT_CHAR;
 831
 832   if (where == PDKIM_HDR_LIMBO)
 833     {
 834     /* In limbo, just wait for a tag-char to appear */
 835     if (!(c >= 'a' && c <= 'z'))
 836       goto NEXT_CHAR;
 837
 838     where = PDKIM_HDR_TAG;
 839     }
 840
 841   if (where == PDKIM_HDR_TAG)
 842     {
 843     if (!cur_tag)
 844       cur_tag = pdkim_strnew(NULL);
 845
 846     if (c >= 'a' && c <= 'z')
 847       pdkim_strncat(cur_tag, p, 1);
 848
 849     if (c == '=')
 850       {
 851       where = PDKIM_HDR_VALUE;
 852       goto NEXT_CHAR;
 853       }
 854     }
 855
 856   if (where == PDKIM_HDR_VALUE)
 857     {
 858     if (!cur_val)
 859       cur_val = pdkim_strnew(NULL);
 860
 861     if (c == '\r' || c == '\n')
 862       goto NEXT_CHAR;
 863
 864     if (c == ';' || c == '\0')
 865       {
 866       if (cur_tag->len > 0)
 867         {
 868         pdkim_strtrim(cur_val);
 869         DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag->str, cur_val->str);
 870
 871         switch (cur_tag->str[0])
 872           {
 873           case 'v':
 874             /* This tag isn't evaluated because:
 875                - We only support version DKIM1.
 876                - Which is the default for this value (set below)
 877                - Other versions are currently not specified.      */
 878             break;
 879           case 'h':
 880             pub->hashes = strdup(cur_val->str); break;
 881           case 'g':
 882             pub->granularity = strdup(cur_val->str); break;
 883           case 'n':
 884             pub->notes = pdkim_decode_qp(cur_val->str); break;
 885           case 'p':
 886             pub->key = pdkim_decode_base64(cur_val->str, &(pub->key_len)); break;
 887           case 'k':
 888             pub->hashes = strdup(cur_val->str); break;
 889           case 's':
 890             pub->srvtype = strdup(cur_val->str); break;
 891           case 't':
 892             if (strchr(cur_val->str, 'y') != NULL) pub->testing = 1;
 893             if (strchr(cur_val->str, 's') != NULL) pub->no_subdomaining = 1;
 894             break;
 895           default:
 896             DEBUG(D_acl) debug_printf(" Unknown tag encountered\n");
 897             break;
 898           }
 899         }
 900       pdkim_strclear(cur_tag);
 901       pdkim_strclear(cur_val);
 902       where = PDKIM_HDR_LIMBO;
 903       }
 904     else
 905       pdkim_strncat(cur_val, p, 1);
 906     }
 907
 908 NEXT_CHAR:
 909   if (c == '\0') break;
 910   }
 911
 912 /* Set fallback defaults */
 913 if (!pub->version    ) pub->version     = strdup(PDKIM_PUB_RECORD_VERSION);
 914 if (!pub->granularity) pub->granularity = strdup("*");
 915 if (!pub->keytype    ) pub->keytype     = strdup("rsa");
 916 if (!pub->srvtype    ) pub->srvtype     = strdup("*");
 917
 918 /* p= is required */
 919 if (pub->key)
 920   return pub;
 921
 922 pdkim_free_pubkey(pub);
 923 return NULL;
 924 }
 925
 926
 927 /* -------------------------------------------------------------------------- */
 928
 929 int
 930 pdkim_update_bodyhash(pdkim_ctx *ctx, const char *data, int len)
 931 {
 932 pdkim_signature *sig = ctx->sig;
 933 /* Cache relaxed version of data */
 934 char *relaxed_data = NULL;
 935 int   relaxed_len  = 0;
 936
 937 /* Traverse all signatures, updating their hashes. */
 938 while (sig)
 939   {
 940   /* Defaults to simple canon (no further treatment necessary) */
 941   const char *canon_data = data;
 942   int         canon_len = len;
 943
 944   if (sig->canon_body == PDKIM_CANON_RELAXED)
 945     {
 946     /* Relax the line if not done already */
 947     if (!relaxed_data)
 948       {
 949       BOOL seen_wsp = FALSE;
 950       const char *p;
 951       int q = 0;
 952
 953       if (!(relaxed_data = malloc(len+1)))
 954         return PDKIM_ERR_OOM;
 955
 956       for (p = data; *p; p++)
 957         {
 958         char c = *p;
 959         if (c == '\r')
 960           {
 961           if (q > 0 && relaxed_data[q-1] == ' ')
 962             q--;
 963           }
 964         else if (c == '\t' || c == ' ')
 965           {
 966           c = ' '; /* Turns WSP into SP */
 967           if (seen_wsp)
 968             continue;
 969           seen_wsp = TRUE;
 970           }
 971         else
 972           seen_wsp = FALSE;
 973         relaxed_data[q++] = c;
 974         }
 975       relaxed_data[q] = '\0';
 976       relaxed_len = q;
 977       }
 978     canon_data = relaxed_data;
 979     canon_len  = relaxed_len;
 980     }
 981
 982   /* Make sure we don't exceed the to-be-signed body length */
 983   if (  sig->bodylength >= 0
 984      && sig->signed_body_bytes + (unsigned long)canon_len > sig->bodylength
 985      )
 986     canon_len = sig->bodylength - sig->signed_body_bytes;
 987
 988   if (canon_len > 0)
 989     {
 990     if (sig->algo == PDKIM_ALGO_RSA_SHA1)
 991       sha1_update(sig->sha1_body, (unsigned char *)canon_data, canon_len);
 992     else
 993       sha2_update(sig->sha2_body, (unsigned char *)canon_data, canon_len);
 994
 995     sig->signed_body_bytes += canon_len;
 996     DEBUG(D_acl) pdkim_quoteprint(canon_data, canon_len, 1);
 997     }
 998
 999   sig = sig->next;
1000   }
1001
1002 if (relaxed_data) free(relaxed_data);
1003 return PDKIM_OK;
1004 }
1005
1006
1007 /* -------------------------------------------------------------------------- */
1008
1009 int
1010 pdkim_finish_bodyhash(pdkim_ctx *ctx)
1011 {
1012 pdkim_signature *sig = ctx->sig;
1013
1014 /* Traverse all signatures */
1015 while (sig)
1016   {                                     /* Finish hashes */
1017   unsigned char bh[32]; /* SHA-256 = 32 Bytes,  SHA-1 = 20 Bytes */
1018
1019   if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1020     sha1_finish(sig->sha1_body, bh);
1021   else
1022     sha2_finish(sig->sha2_body, bh);
1023
1024   DEBUG(D_acl)
1025     {
1026     debug_printf("PDKIM [%s] Body bytes hashed: %lu\n"
1027                  "PDKIM [%s] bh  computed: ",
1028                 sig->domain, sig->signed_body_bytes, sig->domain);
1029     pdkim_hexprint((char *)bh, sig->algo == PDKIM_ALGO_RSA_SHA1 ? 20 : 32, 1);
1030     }
1031
1032   /* SIGNING -------------------------------------------------------------- */
1033   if (ctx->mode == PDKIM_MODE_SIGN)
1034     {
1035     sig->bodyhash_len = (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32;
1036
1037     if (!(sig->bodyhash = malloc(sig->bodyhash_len)))
1038       return PDKIM_ERR_OOM;
1039     memcpy(sig->bodyhash, bh, sig->bodyhash_len);
1040
1041     /* If bodylength limit is set, and we have received less bytes
1042        than the requested amount, effectively remove the limit tag. */
1043     if (sig->signed_body_bytes < sig->bodylength)
1044       sig->bodylength = -1;
1045     }
1046
1047   /* VERIFICATION --------------------------------------------------------- */
1048   else
1049     {
1050     /* Compare bodyhash */
1051     if (memcmp(bh, sig->bodyhash,
1052                (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32) == 0)
1053       {
1054       DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain);
1055       }
1056     else
1057       {
1058       DEBUG(D_acl)
1059         {
1060         debug_printf("PDKIM [%s] bh signature: ", sig->domain);
1061         pdkim_hexprint(sig->bodyhash,
1062                          sig->algo == PDKIM_ALGO_RSA_SHA1 ? 20 : 32, 1);
1063         debug_printf("PDKIM [%s] Body hash did NOT verify\n", sig->domain);
1064         }
1065       sig->verify_status     = PDKIM_VERIFY_FAIL;
1066       sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY;
1067       }
1068     }
1069
1070   sig = sig->next;
1071   }
1072
1073 return PDKIM_OK;
1074 }
1075
1076
1077
1078 /* -------------------------------------------------------------------------- */
1079 /* Callback from pdkim_feed below for processing complete body lines */
1080
1081 static int
1082 pdkim_bodyline_complete(pdkim_ctx *ctx)
1083 {
1084 char *p = ctx->linebuf;
1085 int   n = ctx->linebuf_offset;
1086 pdkim_signature *sig = ctx->sig;        /*XXX assumes only one sig */
1087
1088 /* Ignore extra data if we've seen the end-of-data marker */
1089 if (ctx->seen_eod) goto BAIL;
1090
1091 /* We've always got one extra byte to stuff a zero ... */
1092 ctx->linebuf[ctx->linebuf_offset] = '\0';
1093
1094 /* Terminate on EOD marker */
1095 if (memcmp(p, ".\r\n", 3) == 0)
1096   {
1097   /* In simple body mode, if any empty lines were buffered,
1098   replace with one. rfc 4871 3.4.3 */
1099   /*XXX checking the signed-body-bytes is a gross hack; I think
1100   it indicates that all linebreaks should be buffered, including
1101   the one terminating a text line */
1102   if (  sig && sig->canon_body == PDKIM_CANON_SIMPLE
1103      && sig->signed_body_bytes == 0
1104      && ctx->num_buffered_crlf > 0
1105      )
1106     pdkim_update_bodyhash(ctx, "\r\n", 2);
1107
1108   ctx->seen_eod = TRUE;
1109   goto BAIL;
1110   }
1111 /* Unstuff dots */
1112 if (memcmp(p, "..", 2) == 0)
1113   {
1114   p++;
1115   n--;
1116   }
1117
1118 /* Empty lines need to be buffered until we find a non-empty line */
1119 if (memcmp(p, "\r\n", 2) == 0)
1120   {
1121   ctx->num_buffered_crlf++;
1122   goto BAIL;
1123   }
1124
1125 if (sig && sig->canon_body == PDKIM_CANON_RELAXED)
1126   {
1127   /* Lines with just spaces need to be buffered too */
1128   char *check = p;
1129   while (memcmp(check, "\r\n", 2) != 0)
1130     {
1131     char c = *check;
1132
1133     if (c != '\t' && c != ' ')
1134       goto PROCESS;
1135     check++;
1136     }
1137
1138   ctx->num_buffered_crlf++;
1139   goto BAIL;
1140 }
1141
1142 PROCESS:
1143 /* At this point, we have a non-empty line, so release the buffered ones. */
1144 while (ctx->num_buffered_crlf)
1145   {
1146   pdkim_update_bodyhash(ctx, "\r\n", 2);
1147   ctx->num_buffered_crlf--;
1148   }
1149
1150 pdkim_update_bodyhash(ctx, p, n);
1151
1152 BAIL:
1153 ctx->linebuf_offset = 0;
1154 return PDKIM_OK;
1155 }
1156
1157
1158 /* -------------------------------------------------------------------------- */
1159 /* Callback from pdkim_feed below for processing complete headers */
1160 #define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:"
1161
1162 int
1163 pdkim_header_complete(pdkim_ctx *ctx)
1164 {
1165 /* Special case: The last header can have an extra \r appended */
1166 if ( (ctx->cur_header->len > 1) &&
1167      (ctx->cur_header->str[(ctx->cur_header->len)-1] == '\r') )
1168   {
1169   ctx->cur_header->str[(ctx->cur_header->len)-1] = '\0';
1170   ctx->cur_header->len--;
1171   }
1172
1173 ctx->num_headers++;
1174 if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
1175
1176 /* SIGNING -------------------------------------------------------------- */
1177 if (ctx->mode == PDKIM_MODE_SIGN)
1178   {
1179   pdkim_signature *sig;
1180
1181   for (sig = ctx->sig; sig; sig = sig->next)                    /* Traverse all signatures */
1182     if (header_name_match(ctx->cur_header->str,
1183                           sig->sign_headers?
1184                             sig->sign_headers:
1185                             PDKIM_DEFAULT_SIGN_HEADERS, 0) == PDKIM_OK)
1186       {
1187       pdkim_stringlist *list;
1188
1189       /* Add header to the signed headers list (in reverse order) */
1190       if (!(list = pdkim_prepend_stringlist(sig->headers,
1191                                     ctx->cur_header->str)))
1192         return PDKIM_ERR_OOM;
1193       sig->headers = list;
1194       }
1195   }
1196
1197 /* VERIFICATION ----------------------------------------------------------- */
1198 /* DKIM-Signature: headers are added to the verification list */
1199 if (ctx->mode == PDKIM_MODE_VERIFY)
1200   {
1201   if (strncasecmp(ctx->cur_header->str,
1202                   DKIM_SIGNATURE_HEADERNAME,
1203                   strlen(DKIM_SIGNATURE_HEADERNAME)) == 0)
1204     {
1205     pdkim_signature *new_sig;
1206
1207     /* Create and chain new signature block */
1208     DEBUG(D_acl) debug_printf(
1209         "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1210
1211     if ((new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header->str)))
1212       {
1213       pdkim_signature *last_sig = ctx->sig;
1214       if (!last_sig)
1215         ctx->sig = new_sig;
1216       else
1217         {
1218         while (last_sig->next) last_sig = last_sig->next;
1219         last_sig->next = new_sig;
1220         }
1221       }
1222     else
1223       DEBUG(D_acl) debug_printf(
1224           "Error while parsing signature header\n"
1225           "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1226     }
1227
1228   /* every other header is stored for signature verification */
1229   else
1230     {
1231     pdkim_stringlist *list;
1232
1233     if (!(list = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->str)))
1234       return PDKIM_ERR_OOM;
1235     ctx->headers = list;
1236     }
1237   }
1238
1239 BAIL:
1240 pdkim_strclear(ctx->cur_header); /* Re-use existing pdkim_str */
1241 return PDKIM_OK;
1242 }
1243
1244
1245
1246 /* -------------------------------------------------------------------------- */
1247 #define HEADER_BUFFER_FRAG_SIZE 256
1248
1249 DLLEXPORT int
1250 pdkim_feed (pdkim_ctx *ctx, char *data, int len)
1251 {
1252 int p;
1253
1254 for (p = 0; p<len; p++)
1255   {
1256   char c = data[p];
1257
1258   if (ctx->past_headers)
1259     {
1260     /* Processing body byte */
1261     ctx->linebuf[ctx->linebuf_offset++] = c;
1262     if (c == '\n')
1263       {
1264       int rc = pdkim_bodyline_complete(ctx); /* End of line */
1265       if (rc != PDKIM_OK) return rc;
1266       }
1267     if (ctx->linebuf_offset == (PDKIM_MAX_BODY_LINE_LEN-1))
1268       return PDKIM_ERR_LONG_LINE;
1269     }
1270   else
1271     {
1272     /* Processing header byte */
1273     if (c != '\r')
1274       {
1275       if (c == '\n')
1276         {
1277         if (ctx->seen_lf)
1278           {
1279           int rc = pdkim_header_complete(ctx); /* Seen last header line */
1280           if (rc != PDKIM_OK) return rc;
1281
1282           ctx->past_headers = TRUE;
1283           ctx->seen_lf = 0;
1284           DEBUG(D_acl) debug_printf(
1285               "PDKIM >> Hashed body data, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1286           continue;
1287           }
1288         else
1289           ctx->seen_lf = TRUE;
1290         }
1291       else if (ctx->seen_lf)
1292         {
1293         if (!(c == '\t' || c == ' '))
1294           {
1295           int rc = pdkim_header_complete(ctx); /* End of header */
1296           if (rc != PDKIM_OK) return rc;
1297           }
1298         ctx->seen_lf = FALSE;
1299         }
1300       }
1301
1302     if (!ctx->cur_header)
1303       if (!(ctx->cur_header = pdkim_strnew(NULL)))
1304         return PDKIM_ERR_OOM;
1305
1306     if (ctx->cur_header->len < PDKIM_MAX_HEADER_LEN)
1307       if (!pdkim_strncat(ctx->cur_header, &data[p], 1))
1308         return PDKIM_ERR_OOM;
1309     }
1310   }
1311 return PDKIM_OK;
1312 }
1313
1314 /*
1315  * RFC 5322 specifies that header line length SHOULD be no more than 78
1316  * lets make it so!
1317  *  pdkim_headcat
1318  * returns char*
1319  *
1320  * col: this int holds and receives column number (octets since last '\n')
1321  * str: partial string to append to
1322  * pad: padding, split line or space after before or after eg: ";"
1323  * intro: - must join to payload eg "h=", usually the tag name
1324  * payload: eg base64 data - long data can be split arbitrarily.
1325  *
1326  * this code doesn't fold the header in some of the places that RFC4871
1327  * allows: As per RFC5322(2.2.3) it only folds before or after tag-value
1328  * pairs and inside long values. it also always spaces or breaks after the
1329  * "pad"
1330  *
1331  * no guarantees are made for output given out-of range input. like tag
1332  * names loinger than 78, or bogus col. Input is assumed to be free of line breaks.
1333  */
1334
1335 static char *
1336 pdkim_headcat(int *col, pdkim_str *str, const char * pad,
1337   const char *intro, const char *payload)
1338 {
1339 size_t l;
1340
1341 if (pad)
1342   {
1343   l = strlen(pad);
1344   if (*col + l > 78)
1345     {
1346     pdkim_strcat(str, "\r\n\t");
1347     *col = 1;
1348     }
1349   pdkim_strncat(str, pad, l);
1350   *col += l;
1351   }
1352
1353 l = (pad?1:0) + (intro?strlen(intro):0);
1354
1355 if (*col + l > 78)
1356   { /*can't fit intro - start a new line to make room.*/
1357   pdkim_strcat(str, "\r\n\t");
1358   *col = 1;
1359   l = intro?strlen(intro):0;
1360   }
1361
1362 l += payload ? strlen(payload):0 ;
1363
1364 while (l>77)
1365   { /* this fragment will not fit on a single line */
1366   if (pad)
1367     {
1368     pdkim_strcat(str, " ");
1369     *col += 1;
1370     pad = NULL; /* only want this once */
1371     l--;
1372     }
1373
1374   if (intro)
1375     {
1376     size_t sl = strlen(intro);
1377
1378     pdkim_strncat(str, intro, sl);
1379     *col += sl;
1380     l -= sl;
1381     intro = NULL; /* only want this once */
1382     }
1383
1384   if (payload)
1385     {
1386     size_t sl = strlen(payload);
1387     size_t chomp = *col+sl < 77 ? sl : 78-*col;
1388
1389     pdkim_strncat(str, payload, chomp);
1390     *col += chomp;
1391     payload += chomp;
1392     l -= chomp-1;
1393     }
1394
1395   /* the while precondition tells us it didn't fit. */
1396   pdkim_strcat(str, "\r\n\t");
1397   *col = 1;
1398   }
1399
1400 if (*col + l > 78)
1401   {
1402   pdkim_strcat(str, "\r\n\t");
1403   *col = 1;
1404   pad = NULL;
1405   }
1406
1407 if (pad)
1408   {
1409   pdkim_strcat(str, " ");
1410   *col += 1;
1411   pad = NULL;
1412   }
1413
1414 if (intro)
1415   {
1416   size_t sl = strlen(intro);
1417
1418   pdkim_strncat(str, intro, sl);
1419   *col += sl;
1420   l -= sl;
1421   intro = NULL;
1422   }
1423
1424 if (payload)
1425   {
1426   size_t sl = strlen(payload);
1427
1428   pdkim_strncat(str, payload, sl);
1429   *col += sl;
1430   }
1431
1432 return str->str;
1433 }
1434
1435
1436 /* -------------------------------------------------------------------------- */
1437
1438 char *
1439 pdkim_create_header(pdkim_signature *sig, int final)
1440 {
1441 char *rc = NULL;
1442 char *base64_bh = NULL;
1443 char *base64_b  = NULL;
1444 int col = 0;
1445 pdkim_str *hdr;
1446 pdkim_str *canon_all;
1447
1448 if (!(hdr = pdkim_strnew("DKIM-Signature: v="PDKIM_SIGNATURE_VERSION)))
1449   return NULL;
1450
1451 if (!(canon_all = pdkim_strnew(pdkim_canons[sig->canon_headers])))
1452   goto BAIL;
1453
1454 if (!(base64_bh = pdkim_encode_base64(sig->bodyhash, sig->bodyhash_len)))
1455   goto BAIL;
1456
1457 col = strlen(hdr->str);
1458
1459 /* Required and static bits */
1460 if (  pdkim_headcat(&col, hdr, ";", "a=", pdkim_algos[sig->algo])
1461    && pdkim_headcat(&col, hdr, ";", "q=", pdkim_querymethods[sig->querymethod])
1462    && pdkim_strcat(canon_all, "/")
1463    && pdkim_strcat(canon_all, pdkim_canons[sig->canon_body])
1464    && pdkim_headcat(&col, hdr, ";", "c=", canon_all->str)
1465    && pdkim_headcat(&col, hdr, ";", "d=", sig->domain)
1466    && pdkim_headcat(&col, hdr, ";", "s=", sig->selector)
1467    )
1468   {
1469   /* list of eader names can be split between items. */
1470     {
1471     char *n = strdup(sig->headernames);
1472     char *f = n;
1473     char *i = "h=";
1474     char *s = ";";
1475
1476     if (!n) goto BAIL;
1477     while (*n)
1478       {
1479       char *c = strchr(n, ':');
1480
1481       if (c) *c ='\0';
1482
1483       if (!i)
1484         if (!pdkim_headcat(&col, hdr, NULL, NULL, ":"))
1485           {
1486           free(f);
1487           goto BAIL;
1488           }
1489
1490       if (!pdkim_headcat(&col, hdr, s, i, n))
1491         {
1492         free(f);
1493         goto BAIL;
1494         }
1495
1496       if (!c)
1497         break;
1498
1499       n = c+1;
1500       s = NULL;
1501       i = NULL;
1502       }
1503     free(f);
1504     }
1505
1506   if(!pdkim_headcat(&col, hdr, ";", "bh=", base64_bh))
1507     goto BAIL;
1508
1509   /* Optional bits */
1510   if (sig->identity)
1511     if(!pdkim_headcat(&col, hdr, ";", "i=", sig->identity))
1512       goto BAIL;
1513
1514   if (sig->created > 0)
1515     {
1516     char minibuf[20];
1517
1518     snprintf(minibuf, 20, "%lu", sig->created);
1519     if(!pdkim_headcat(&col, hdr, ";", "t=", minibuf))
1520       goto BAIL;
1521   }
1522
1523   if (sig->expires > 0)
1524     {
1525     char minibuf[20];
1526
1527     snprintf(minibuf, 20, "%lu", sig->expires);
1528     if(!pdkim_headcat(&col, hdr, ";", "x=", minibuf))
1529       goto BAIL;
1530     }
1531
1532   if (sig->bodylength >= 0)
1533     {
1534     char minibuf[20];
1535
1536     snprintf(minibuf, 20, "%lu", sig->bodylength);
1537     if(!pdkim_headcat(&col, hdr, ";", "l=", minibuf))
1538       goto BAIL;
1539     }
1540
1541   /* Preliminary or final version? */
1542   if (final)
1543     {
1544     if (!(base64_b = pdkim_encode_base64(sig->sigdata, sig->sigdata_len)))
1545       goto BAIL;
1546     if (!pdkim_headcat(&col, hdr, ";", "b=", base64_b))
1547       goto BAIL;
1548   }
1549   else
1550     if(!pdkim_headcat(&col, hdr, ";", "b=", ""))
1551       goto BAIL;
1552
1553   /* add trailing semicolon: I'm not sure if this is actually needed */
1554   if (!pdkim_headcat(&col, hdr, NULL, ";", ""))
1555     goto BAIL;
1556   }
1557
1558 rc = strdup(hdr->str);
1559
1560 BAIL:
1561 pdkim_strfree(hdr);
1562 if (canon_all) pdkim_strfree(canon_all);
1563 if (base64_bh) free(base64_bh);
1564 if (base64_b ) free(base64_b);
1565 return rc;
1566 }
1567
1568
1569 /* -------------------------------------------------------------------------- */
1570
1571 DLLEXPORT int
1572 pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures)
1573 {
1574 pdkim_signature *sig = ctx->sig;
1575 pdkim_str *headernames = NULL;             /* Collected signed header names */
1576
1577 /* Check if we must still flush a (partial) header. If that is the
1578    case, the message has no body, and we must compute a body hash
1579    out of '<CR><LF>' */
1580 if (ctx->cur_header && ctx->cur_header->len)
1581   {
1582   int rc = pdkim_header_complete(ctx);
1583   if (rc != PDKIM_OK) return rc;
1584   pdkim_update_bodyhash(ctx, "\r\n", 2);
1585   }
1586 else
1587   DEBUG(D_acl) debug_printf(
1588       "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1589
1590 /* Build (and/or evaluate) body hash */
1591 if (pdkim_finish_bodyhash(ctx) != PDKIM_OK)
1592   return PDKIM_ERR_OOM;
1593
1594 /* SIGNING -------------------------------------------------------------- */
1595 if (ctx->mode == PDKIM_MODE_SIGN)
1596   if (!(headernames = pdkim_strnew(NULL)))
1597     return PDKIM_ERR_OOM;
1598 /* ---------------------------------------------------------------------- */
1599
1600 while (sig)
1601   {
1602   sha1_context sha1_headers;
1603   sha2_context sha2_headers;
1604   char *sig_hdr;
1605   char headerhash[32];
1606
1607   if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1608     sha1_starts(&sha1_headers);
1609   else
1610     sha2_starts(&sha2_headers, 0);
1611
1612   DEBUG(D_acl) debug_printf(
1613       "PDKIM >> Hashed header data, canonicalized, in sequence >>>>>>>>>>>>>>\n");
1614
1615   /* SIGNING ---------------------------------------------------------------- */
1616   /* When signing, walk through our header list and add them to the hash. As we
1617      go, construct a list of the header's names to use for the h= parameter. */
1618
1619   if (ctx->mode == PDKIM_MODE_SIGN)
1620     {
1621     pdkim_stringlist *p;
1622
1623     for (p = sig->headers; p; p = p->next)
1624       {
1625       char *rh = NULL;
1626       /* Collect header names (Note: colon presence is guaranteed here) */
1627       char *q = strchr(p->value, ':');
1628
1629       if (!(pdkim_strncat(headernames, p->value,
1630                         (q-(p->value)) + (p->next ? 1 : 0))))
1631         return PDKIM_ERR_OOM;
1632
1633       rh = sig->canon_headers == PDKIM_CANON_RELAXED
1634         ? pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */
1635         : strdup(p->value);              /* just copy it for simple canon */
1636       if (!rh)
1637         return PDKIM_ERR_OOM;
1638
1639       /* Feed header to the hash algorithm */
1640       if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1641         sha1_update(&(sha1_headers), (unsigned char *)rh, strlen(rh));
1642       else
1643         sha2_update(&(sha2_headers), (unsigned char *)rh, strlen(rh));
1644
1645       DEBUG(D_acl) pdkim_quoteprint(rh, strlen(rh), 1);
1646       free(rh);
1647       }
1648     }
1649
1650   /* VERIFICATION ----------------------------------------------------------- */
1651   /* When verifying, walk through the header name list in the h= parameter and
1652      add the headers to the hash in that order. */
1653   else
1654     {
1655     char *b = strdup(sig->headernames);
1656     char *p = b;
1657     char *q = NULL;
1658     pdkim_stringlist *hdrs;
1659
1660     if (!b) return PDKIM_ERR_OOM;
1661
1662     /* clear tags */
1663     for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
1664       hdrs->tag = 0;
1665
1666     while(1)
1667       {
1668       if ((q = strchr(p, ':')))
1669         *q = '\0';
1670
1671       for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
1672         if (  hdrs->tag == 0
1673            && strncasecmp(hdrs->value, p, strlen(p)) == 0
1674            && (hdrs->value)[strlen(p)] == ':'
1675            )
1676           {
1677           char *rh;
1678
1679           rh = sig->canon_headers == PDKIM_CANON_RELAXED
1680             ? pdkim_relax_header(hdrs->value, 1) /* cook header for relaxed canon */
1681             : strdup(hdrs->value);               /* just copy it for simple canon */
1682           if (!rh)
1683             return PDKIM_ERR_OOM;
1684
1685           /* Feed header to the hash algorithm */
1686           if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1687             sha1_update(&sha1_headers, (unsigned char *)rh, strlen(rh));
1688           else
1689             sha2_update(&sha2_headers, (unsigned char *)rh, strlen(rh));
1690
1691           DEBUG(D_acl) pdkim_quoteprint(rh, strlen(rh), 1);
1692           free(rh);
1693           hdrs->tag = 1;
1694           break;
1695           }
1696
1697       if (!q) break;
1698       p = q+1;
1699       }
1700     free(b);
1701     }
1702
1703   DEBUG(D_acl) debug_printf(
1704             "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1705
1706   /* SIGNING ---------------------------------------------------------------- */
1707   if (ctx->mode == PDKIM_MODE_SIGN)
1708     {
1709     /* Copy headernames to signature struct */
1710     sig->headernames = strdup(headernames->str);
1711     pdkim_strfree(headernames);
1712
1713     /* Create signature header with b= omitted */
1714     sig_hdr = pdkim_create_header(ctx->sig, 0);
1715     }
1716
1717   /* VERIFICATION ----------------------------------------------------------- */
1718   else
1719     sig_hdr = strdup(sig->rawsig_no_b_val);
1720   /* ------------------------------------------------------------------------ */
1721
1722   if (!sig_hdr)
1723     return PDKIM_ERR_OOM;
1724
1725   /* Relax header if necessary */
1726   if (sig->canon_headers == PDKIM_CANON_RELAXED)
1727     {
1728     char *relaxed_hdr = pdkim_relax_header(sig_hdr, 0);
1729
1730     free(sig_hdr);
1731     if (!relaxed_hdr)
1732       return PDKIM_ERR_OOM;
1733     sig_hdr = relaxed_hdr;
1734     }
1735
1736   DEBUG(D_acl)
1737     {
1738     debug_printf(
1739             "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
1740     pdkim_quoteprint(sig_hdr, strlen(sig_hdr), 1);
1741     debug_printf(
1742             "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1743     }
1744
1745   /* Finalize header hash */
1746   if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1747     {
1748     sha1_update(&sha1_headers, (unsigned char *)sig_hdr, strlen(sig_hdr));
1749     sha1_finish(&sha1_headers, (unsigned char *)headerhash);
1750
1751     DEBUG(D_acl)
1752       {
1753       debug_printf( "PDKIM [%s] hh computed: ", sig->domain);
1754       pdkim_hexprint(headerhash, 20, 1);
1755       }
1756     }
1757   else
1758     {
1759     sha2_update(&sha2_headers, (unsigned char *)sig_hdr, strlen(sig_hdr));
1760     sha2_finish(&sha2_headers, (unsigned char *)headerhash);
1761
1762     DEBUG(D_acl)
1763       {
1764       debug_printf("PDKIM [%s] hh computed: ", sig->domain);
1765       pdkim_hexprint(headerhash, 32, 1);
1766       }
1767     }
1768
1769   free(sig_hdr);
1770
1771   /* SIGNING ---------------------------------------------------------------- */
1772   if (ctx->mode == PDKIM_MODE_SIGN)
1773     {
1774     rsa_context rsa;
1775
1776     rsa_init(&rsa, RSA_PKCS_V15, 0);
1777
1778     /* Perform private key operation */
1779     if (rsa_parse_key(&rsa, (unsigned char *)sig->rsa_privkey,
1780                       strlen(sig->rsa_privkey), NULL, 0) != 0)
1781       return PDKIM_ERR_RSA_PRIVKEY;
1782
1783     sig->sigdata_len = mpi_size(&(rsa.N));
1784     if (!(sig->sigdata = malloc(sig->sigdata_len)))
1785       return PDKIM_ERR_OOM;
1786
1787     if (rsa_pkcs1_sign( &rsa, RSA_PRIVATE,
1788                         ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1789                            SIG_RSA_SHA1:SIG_RSA_SHA256),
1790                         0,
1791                         (unsigned char *)headerhash,
1792                         (unsigned char *)sig->sigdata ) != 0)
1793       return PDKIM_ERR_RSA_SIGNING;
1794
1795     rsa_free(&rsa);
1796
1797     DEBUG(D_acl)
1798       {
1799       debug_printf( "PDKIM [%s] b computed: ", sig->domain);
1800       pdkim_hexprint(sig->sigdata, sig->sigdata_len, 1);
1801       }
1802
1803     if (!(sig->signature_header = pdkim_create_header(ctx->sig, 1)))
1804       return PDKIM_ERR_OOM;
1805     }
1806
1807   /* VERIFICATION ----------------------------------------------------------- */
1808   else
1809     {
1810     rsa_context rsa;
1811     char *dns_txt_name, *dns_txt_reply;
1812
1813     rsa_init(&rsa, RSA_PKCS_V15, 0);
1814
1815     if (!(dns_txt_name  = malloc(PDKIM_DNS_TXT_MAX_NAMELEN)))
1816       return PDKIM_ERR_OOM;
1817
1818     if (!(dns_txt_reply = malloc(PDKIM_DNS_TXT_MAX_RECLEN)))
1819       {
1820       free(dns_txt_name);
1821       return PDKIM_ERR_OOM;
1822       }
1823
1824     memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN);
1825     memset(dns_txt_name , 0, PDKIM_DNS_TXT_MAX_NAMELEN);
1826
1827     if (snprintf(dns_txt_name, PDKIM_DNS_TXT_MAX_NAMELEN,
1828                  "%s._domainkey.%s.",
1829                  sig->selector, sig->domain) >= PDKIM_DNS_TXT_MAX_NAMELEN)
1830       {
1831       sig->verify_status =      PDKIM_VERIFY_INVALID;
1832       sig->verify_ext_status =  PDKIM_VERIFY_INVALID_BUFFER_SIZE;
1833       goto NEXT_VERIFY;
1834       }
1835
1836     if (  ctx->dns_txt_callback(dns_txt_name, dns_txt_reply) != PDKIM_OK
1837        || dns_txt_reply[0] == '\0')
1838       {
1839       sig->verify_status =      PDKIM_VERIFY_INVALID;
1840       sig->verify_ext_status =  PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
1841       goto NEXT_VERIFY;
1842       }
1843
1844     DEBUG(D_acl)
1845       {
1846       debug_printf(
1847               "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"
1848               " Raw record: ");
1849       pdkim_quoteprint(dns_txt_reply, strlen(dns_txt_reply), 1);
1850       }
1851
1852     if (!(sig->pubkey = pdkim_parse_pubkey_record(ctx, dns_txt_reply)))
1853       {
1854       sig->verify_status =      PDKIM_VERIFY_INVALID;
1855       sig->verify_ext_status =  PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1856
1857       DEBUG(D_acl) debug_printf(
1858           " Error while parsing public key record\n"
1859           "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1860       goto NEXT_VERIFY;
1861       }
1862
1863     DEBUG(D_acl) debug_printf(
1864         "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1865
1866     if (rsa_parse_public_key(&rsa,
1867                             (unsigned char *)sig->pubkey->key,
1868                              sig->pubkey->key_len) != 0)
1869       {
1870       sig->verify_status =      PDKIM_VERIFY_INVALID;
1871       sig->verify_ext_status =  PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1872       goto NEXT_VERIFY;
1873       }
1874
1875     /* Check the signature */
1876     if (rsa_pkcs1_verify(&rsa,
1877                       RSA_PUBLIC,
1878                       ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1879                            SIG_RSA_SHA1:SIG_RSA_SHA256),
1880                       0,
1881                       (unsigned char *)headerhash,
1882                       (unsigned char *)sig->sigdata) != 0)
1883       {
1884       sig->verify_status =      PDKIM_VERIFY_FAIL;
1885       sig->verify_ext_status =  PDKIM_VERIFY_FAIL_MESSAGE;
1886       goto NEXT_VERIFY;
1887       }
1888
1889     /* We have a winner! (if bodydhash was correct earlier) */
1890     if (sig->verify_status == PDKIM_VERIFY_NONE)
1891       sig->verify_status = PDKIM_VERIFY_PASS;
1892
1893 NEXT_VERIFY:
1894
1895     DEBUG(D_acl)
1896       {
1897       debug_printf("PDKIM [%s] signature status: %s",
1898               sig->domain, pdkim_verify_status_str(sig->verify_status));
1899       if (sig->verify_ext_status > 0)
1900         debug_printf(" (%s)\n",
1901                 pdkim_verify_ext_status_str(sig->verify_ext_status));
1902       else
1903         debug_printf("\n");
1904       }
1905
1906     rsa_free(&rsa);
1907     free(dns_txt_name);
1908     free(dns_txt_reply);
1909     }
1910
1911   sig = sig->next;
1912   }
1913
1914 /* If requested, set return pointer to signature(s) */
1915 if (return_signatures)
1916   *return_signatures = ctx->sig;
1917
1918 return PDKIM_OK;
1919 }
1920
1921
1922 /* -------------------------------------------------------------------------- */
1923
1924 DLLEXPORT pdkim_ctx *
1925 pdkim_init_verify(int(*dns_txt_callback)(char *, char *))
1926 {
1927 pdkim_ctx *ctx = malloc(sizeof(pdkim_ctx));
1928
1929 if (!ctx)
1930   return NULL;
1931 memset(ctx, 0, sizeof(pdkim_ctx));
1932
1933 if (!(ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN)))
1934   {
1935   free(ctx);
1936   return NULL;
1937   }
1938
1939 ctx->mode = PDKIM_MODE_VERIFY;
1940 ctx->dns_txt_callback = dns_txt_callback;
1941
1942 return ctx;
1943 }
1944
1945
1946 /* -------------------------------------------------------------------------- */
1947
1948 DLLEXPORT pdkim_ctx *
1949 pdkim_init_sign(char *domain, char *selector, char *rsa_privkey)
1950 {
1951 pdkim_ctx *ctx;
1952 pdkim_signature *sig;
1953
1954 if (!domain || !selector || !rsa_privkey)
1955   return NULL;
1956
1957 if (!(ctx = malloc(sizeof(pdkim_ctx))))
1958   return NULL;
1959 memset(ctx, 0, sizeof(pdkim_ctx));
1960
1961 if (!(ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN)))
1962   {
1963   free(ctx);
1964   return NULL;
1965   }
1966
1967 if (!(sig = malloc(sizeof(pdkim_signature))))
1968   {
1969   free(ctx->linebuf);
1970   free(ctx);
1971   return NULL;
1972   }
1973 memset(sig, 0, sizeof(pdkim_signature));
1974
1975 sig->bodylength = -1;
1976
1977 ctx->mode = PDKIM_MODE_SIGN;
1978 ctx->sig = sig;
1979
1980 ctx->sig->domain = strdup(domain);
1981 ctx->sig->selector = strdup(selector);
1982 ctx->sig->rsa_privkey = strdup(rsa_privkey);
1983
1984 if (!ctx->sig->domain || !ctx->sig->selector || !ctx->sig->rsa_privkey)
1985   goto BAIL;
1986
1987 if (!(ctx->sig->sha1_body = malloc(sizeof(sha1_context))))
1988   goto BAIL;
1989 sha1_starts(ctx->sig->sha1_body);
1990
1991 if (!(ctx->sig->sha2_body = malloc(sizeof(sha2_context))))
1992   goto BAIL;
1993 sha2_starts(ctx->sig->sha2_body, 0);
1994
1995 return ctx;
1996
1997 BAIL:
1998   pdkim_free_ctx(ctx);
1999   return NULL;
2000 }
2001
2002 /* -------------------------------------------------------------------------- */
2003
2004 DLLEXPORT int
2005 pdkim_set_optional(pdkim_ctx *ctx,
2006                        char *sign_headers,
2007                        char *identity,
2008                        int canon_headers,
2009                        int canon_body,
2010                        long bodylength,
2011                        int algo,
2012                        unsigned long created,
2013                        unsigned long expires)
2014 {
2015
2016 if (identity)
2017   if (!(ctx->sig->identity = strdup(identity)))
2018     return PDKIM_ERR_OOM;
2019
2020 if (sign_headers)
2021   if (!(ctx->sig->sign_headers = strdup(sign_headers)))
2022     return PDKIM_ERR_OOM;
2023
2024 ctx->sig->canon_headers = canon_headers;
2025 ctx->sig->canon_body = canon_body;
2026 ctx->sig->bodylength = bodylength;
2027 ctx->sig->algo = algo;
2028 ctx->sig->created = created;
2029 ctx->sig->expires = expires;
2030
2031 return PDKIM_OK;
2032 }
2033
2034