src/src/pdkim/pdkim.c

   1 /*
   2  *  PDKIM - a RFC4871 (DKIM) implementation
   3  *
   4  *  Copyright (C) 2009  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 /* $Cambridge: exim/src/src/pdkim/pdkim.c,v 1.7 2009/11/09 14:19:48 tom Exp $ */
  24
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <ctype.h>
  29
  30 #include "pdkim.h"
  31
  32 #include "sha1.h"
  33 #include "sha2.h"
  34 #include "rsa.h"
  35 #include "base64.h"
  36
  37 #define PDKIM_SIGNATURE_VERSION     "1"
  38 #define PDKIM_PUB_RECORD_VERSION    "DKIM1"
  39
  40 #define PDKIM_MAX_HEADER_LEN        65536
  41 #define PDKIM_MAX_HEADERS           512
  42 #define PDKIM_MAX_BODY_LINE_LEN     16384
  43 #define PDKIM_DNS_TXT_MAX_NAMELEN   1024
  44 #define PDKIM_DEFAULT_SIGN_HEADERS "From:Sender:Reply-To:Subject:Date:"\
  45                              "Message-ID:To:Cc:MIME-Version:Content-Type:"\
  46                              "Content-Transfer-Encoding:Content-ID:"\
  47                              "Content-Description:Resent-Date:Resent-From:"\
  48                              "Resent-Sender:Resent-To:Resent-Cc:"\
  49                              "Resent-Message-ID:In-Reply-To:References:"\
  50                              "List-Id:List-Help:List-Unsubscribe:"\
  51                              "List-Subscribe:List-Post:List-Owner:List-Archive"
  52
  53 /* -------------------------------------------------------------------------- */
  54 struct pdkim_stringlist {
  55   char *value;
  56   void *next;
  57 };
  58
  59 #define PDKIM_STR_ALLOC_FRAG 256
  60 struct pdkim_str {
  61   char         *str;
  62   unsigned int  len;
  63   unsigned int  allocated;
  64 };
  65
  66 /* -------------------------------------------------------------------------- */
  67 /* A bunch of list constants */
  68 char *pdkim_querymethods[] = {
  69   "dns/txt",
  70   NULL
  71 };
  72 char *pdkim_algos[] = {
  73   "rsa-sha256",
  74   "rsa-sha1",
  75   NULL
  76 };
  77 char *pdkim_canons[] = {
  78   "simple",
  79   "relaxed",
  80   NULL
  81 };
  82 char *pdkim_hashes[] = {
  83   "sha256",
  84   "sha1",
  85   NULL
  86 };
  87 char *pdkim_keytypes[] = {
  88   "rsa",
  89   NULL
  90 };
  91
  92 typedef struct pdkim_combined_canon_entry {
  93   char *str;
  94   int canon_headers;
  95   int canon_body;
  96 } pdkim_combined_canon_entry;
  97 pdkim_combined_canon_entry pdkim_combined_canons[] = {
  98   { "simple/simple",    PDKIM_CANON_SIMPLE,   PDKIM_CANON_SIMPLE },
  99   { "simple/relaxed",   PDKIM_CANON_SIMPLE,   PDKIM_CANON_RELAXED },
 100   { "relaxed/simple",   PDKIM_CANON_RELAXED,  PDKIM_CANON_SIMPLE },
 101   { "relaxed/relaxed",  PDKIM_CANON_RELAXED,  PDKIM_CANON_RELAXED },
 102   { "simple",           PDKIM_CANON_SIMPLE,   PDKIM_CANON_SIMPLE },
 103   { "relaxed",          PDKIM_CANON_RELAXED,  PDKIM_CANON_SIMPLE },
 104   { NULL,               0,                    0 }
 105 };
 106
 107
 108 /* -------------------------------------------------------------------------- */
 109 /* Print debugging functions */
 110 #ifdef PDKIM_DEBUG
 111 void pdkim_quoteprint(FILE *stream, char *data, int len, int lf) {
 112   int i;
 113   unsigned char *p = (unsigned char *)data;
 114
 115   for (i=0;i<len;i++) {
 116     int c = p[i];
 117     switch (c) {
 118       case ' ' : fprintf(stream,"{SP}"); break;
 119       case '\t': fprintf(stream,"{TB}"); break;
 120       case '\r': fprintf(stream,"{CR}"); break;
 121       case '\n': fprintf(stream,"{LF}"); break;
 122       case '{' : fprintf(stream,"{BO}"); break;
 123       case '}' : fprintf(stream,"{BC}"); break;
 124       default:
 125         if ( (c < 32) || (c > 127) )
 126           fprintf(stream,"{%02x}",c);
 127         else
 128           fputc(c,stream);
 129       break;
 130     }
 131   }
 132   if (lf)
 133     fputc('\n',stream);
 134 }
 135 void pdkim_hexprint(FILE *stream, char *data, int len, int lf) {
 136   int i;
 137   unsigned char *p = (unsigned char *)data;
 138
 139   for (i=0;i<len;i++) {
 140     int c = p[i];
 141     fprintf(stream,"%02x",c);
 142   }
 143   if (lf)
 144     fputc('\n',stream);
 145 }
 146 #endif
 147
 148
 149 /* -------------------------------------------------------------------------- */
 150 /* Simple string list implementation for convinience */
 151 pdkim_stringlist *pdkim_append_stringlist(pdkim_stringlist *base, char *str) {
 152   pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
 153   if (new_entry == NULL) return NULL;
 154   memset(new_entry,0,sizeof(pdkim_stringlist));
 155   new_entry->value = strdup(str);
 156   if (new_entry->value == NULL) return NULL;
 157   if (base != NULL) {
 158     pdkim_stringlist *last = base;
 159     while (last->next != NULL) { last = last->next; }
 160     last->next = new_entry;
 161     return base;
 162   }
 163   else return new_entry;
 164 }
 165 pdkim_stringlist *pdkim_prepend_stringlist(pdkim_stringlist *base, char *str) {
 166   pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
 167   if (new_entry == NULL) return NULL;
 168   memset(new_entry,0,sizeof(pdkim_stringlist));
 169   new_entry->value = strdup(str);
 170   if (new_entry->value == NULL) return NULL;
 171   if (base != NULL) {
 172     new_entry->next = base;
 173   }
 174   return new_entry;
 175 }
 176
 177
 178 /* -------------------------------------------------------------------------- */
 179 /* A small "growing string" implementation to escape malloc/realloc hell */
 180 pdkim_str *pdkim_strnew (char *cstr) {
 181   unsigned int len = cstr?strlen(cstr):0;
 182   pdkim_str *p = malloc(sizeof(pdkim_str));
 183   if (p == NULL) return NULL;
 184   memset(p,0,sizeof(pdkim_str));
 185   p->str = malloc(len+1);
 186   if (p->str == NULL) {
 187     free(p);
 188     return NULL;
 189   }
 190   p->allocated=(len+1);
 191   p->len=len;
 192   if (cstr) strcpy(p->str,cstr);
 193   return p;
 194 }
 195 char *pdkim_strncat(pdkim_str *str, char *data, int len) {
 196   if ((str->allocated - str->len) < (len+1)) {
 197     /* Extend the buffer */
 198     int num_frags = ((len+1)/PDKIM_STR_ALLOC_FRAG)+1;
 199     char *n = realloc(str->str,
 200                       (str->allocated+(num_frags*PDKIM_STR_ALLOC_FRAG)));
 201     if (n == NULL) return NULL;
 202     str->str = n;
 203     str->allocated += (num_frags*PDKIM_STR_ALLOC_FRAG);
 204   }
 205   strncpy(&(str->str[str->len]),data,len);
 206   str->len+=len;
 207   str->str[str->len] = '\0';
 208   return str->str;
 209 }
 210 char *pdkim_strcat(pdkim_str *str, char *cstr) {
 211   return pdkim_strncat(str, cstr, strlen(cstr));
 212 }
 213 char *pdkim_numcat(pdkim_str *str, unsigned long num) {
 214   char minibuf[20];
 215   snprintf(minibuf,20,"%lu",num);
 216   return pdkim_strcat(str,minibuf);
 217 }
 218 char *pdkim_strtrim(pdkim_str *str) {
 219   char *p = str->str;
 220   char *q = str->str;
 221   while ( (*p != '\0') && ((*p == '\t') || (*p == ' ')) ) p++;
 222   while (*p != '\0') {*q = *p; q++; p++;}
 223   *q = '\0';
 224   while ( (q != str->str) && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) ) {
 225     *q = '\0';
 226     q--;
 227   }
 228   str->len = strlen(str->str);
 229   return str->str;
 230 }
 231 char *pdkim_strclear(pdkim_str *str) {
 232   str->str[0] = '\0';
 233   str->len = 0;
 234   return str->str;
 235 }
 236 void pdkim_strfree(pdkim_str *str) {
 237   if (str == NULL) return;
 238   if (str->str != NULL) free(str->str);
 239   free(str);
 240 }
 241
 242
 243
 244 /* -------------------------------------------------------------------------- */
 245 void pdkim_free_pubkey(pdkim_pubkey *pub) {
 246   if (pub) {
 247     if (pub->version        != NULL) free(pub->version);
 248     if (pub->granularity    != NULL) free(pub->granularity);
 249     if (pub->hashes         != NULL) free(pub->hashes);
 250     if (pub->keytype        != NULL) free(pub->keytype);
 251     if (pub->srvtype        != NULL) free(pub->srvtype);
 252     if (pub->notes          != NULL) free(pub->notes);
 253     if (pub->key            != NULL) free(pub->key);
 254     free(pub);
 255   }
 256 }
 257
 258
 259 /* -------------------------------------------------------------------------- */
 260 void pdkim_free_sig(pdkim_signature *sig) {
 261   if (sig) {
 262     pdkim_signature *next = (pdkim_signature *)sig->next;
 263
 264     pdkim_stringlist *e = sig->headers;
 265     while(e != NULL) {
 266       pdkim_stringlist *c = e;
 267       if (e->value != NULL) free(e->value);
 268       e = e->next;
 269       free(c);
 270     }
 271
 272     if (sig->sigdata          != NULL) free(sig->sigdata);
 273     if (sig->bodyhash         != NULL) free(sig->bodyhash);
 274     if (sig->selector         != NULL) free(sig->selector);
 275     if (sig->domain           != NULL) free(sig->domain);
 276     if (sig->identity         != NULL) free(sig->identity);
 277     if (sig->headernames      != NULL) free(sig->headernames);
 278     if (sig->copiedheaders    != NULL) free(sig->copiedheaders);
 279     if (sig->rsa_privkey      != NULL) free(sig->rsa_privkey);
 280     if (sig->sign_headers     != NULL) free(sig->sign_headers);
 281     if (sig->signature_header != NULL) free(sig->signature_header);
 282     if (sig->sha1_body        != NULL) free(sig->sha1_body);
 283     if (sig->sha2_body        != NULL) free(sig->sha2_body);
 284     if (sig->hnames_check     != NULL) free(sig->hnames_check);
 285
 286     if (sig->pubkey != NULL) pdkim_free_pubkey(sig->pubkey);
 287
 288     free(sig);
 289     if (next != NULL) pdkim_free_sig(next);
 290   }
 291 }
 292
 293
 294 /* -------------------------------------------------------------------------- */
 295 DLLEXPORT void pdkim_free_ctx(pdkim_ctx *ctx) {
 296   if (ctx) {
 297     pdkim_free_sig(ctx->sig);
 298     pdkim_strfree(ctx->cur_header);
 299     free(ctx);
 300   }
 301 }
 302
 303
 304 /* -------------------------------------------------------------------------- */
 305 /* Matches the name of the passed raw "header" against
 306    the passed colon-separated "list", starting at entry
 307    "start". Returns the position of the header name in
 308    the list. */
 309 int header_name_match(char *header,
 310                       char *tick,
 311                       int   do_tick) {
 312   char *hname;
 313   char *lcopy;
 314   char *p;
 315   char *q;
 316   int rc = PDKIM_FAIL;
 317
 318   /* Get header name */
 319   char *hcolon = strchr(header,':');
 320   if (hcolon == NULL) return rc; /* This isn't a header */
 321   hname = malloc((hcolon-header)+1);
 322   if (hname == NULL) return PDKIM_ERR_OOM;
 323   memset(hname,0,(hcolon-header)+1);
 324   strncpy(hname,header,(hcolon-header));
 325
 326   /* Copy tick-off list locally, so we can punch zeroes into it */
 327   lcopy = strdup(tick);
 328   if (lcopy == NULL) {
 329     free(hname);
 330     return PDKIM_ERR_OOM;
 331   }
 332   p = lcopy;
 333   q = strchr(p,':');
 334   while (q != NULL) {
 335     *q = '\0';
 336
 337     if (strcasecmp(p,hname) == 0) {
 338       rc = PDKIM_OK;
 339       /* Invalidate header name instance in tick-off list */
 340       if (do_tick) tick[p-lcopy] = '_';
 341       goto BAIL;
 342     }
 343
 344     p = q+1;
 345     q = strchr(p,':');
 346   }
 347
 348   if (strcasecmp(p,hname) == 0) {
 349     rc = PDKIM_OK;
 350     /* Invalidate header name instance in tick-off list */
 351     if (do_tick) tick[p-lcopy] = '_';
 352   }
 353
 354   BAIL:
 355   free(hname);
 356   free(lcopy);
 357   return rc;
 358 }
 359
 360
 361 /* -------------------------------------------------------------------------- */
 362 /* Performs "relaxed" canonicalization of a header. The returned pointer needs
 363    to be free()d. */
 364 char *pdkim_relax_header (char *header, int crlf) {
 365   int past_field_name = 0;
 366   int seen_wsp = 0;
 367   char *p = header;
 368   char *q;
 369   char *relaxed = malloc(strlen(header)+3);
 370   if (relaxed == NULL) return NULL;
 371   q = relaxed;
 372   while (*p != '\0') {
 373     int c = *p;
 374     /* Ignore CR & LF */
 375     if ( (c == '\r') || (c == '\n') ) {
 376       p++;
 377       continue;
 378     }
 379     if ( (c == '\t') || (c == ' ') ) {
 380       c = ' '; /* Turns WSP into SP */
 381       if (seen_wsp) {
 382         p++;
 383         continue;
 384       }
 385       else seen_wsp = 1;
 386     }
 387     else {
 388       if ( (!past_field_name) && (c == ':') ) {
 389         if (seen_wsp) q--;   /* This removes WSP before the colon */
 390         seen_wsp = 1;        /* This removes WSP after the colon */
 391         past_field_name = 1;
 392       }
 393       else seen_wsp = 0;
 394     }
 395     /* Lowercase header name */
 396     if (!past_field_name) c = tolower(c);
 397     *q = c;
 398     p++;
 399     q++;
 400   }
 401   *q = '\0';
 402   if (crlf) strcat(relaxed,"\r\n");
 403   return relaxed;
 404 }
 405
 406
 407 /* -------------------------------------------------------------------------- */
 408 #define PDKIM_QP_ERROR_DECODE -1
 409 char *pdkim_decode_qp_char(char *qp_p, int *c) {
 410   char *initial_pos = qp_p;
 411
 412   /* Advance one char */
 413   qp_p++;
 414
 415   /* Check for two hex digits and decode them */
 416   if (isxdigit(*qp_p) && isxdigit(qp_p[1])) {
 417     /* Do hex conversion */
 418     if (isdigit(*qp_p)) {*c = *qp_p - '0';}
 419     else {*c = toupper(*qp_p) - 'A' + 10;}
 420     *c <<= 4;
 421     if (isdigit(qp_p[1])) {*c |= qp_p[1] - '0';}
 422     else {*c |= toupper(qp_p[1]) - 'A' + 10;}
 423     return qp_p + 2;
 424   }
 425
 426   /* Illegal char here */
 427   *c = PDKIM_QP_ERROR_DECODE;
 428   return initial_pos;
 429 }
 430
 431
 432 /* -------------------------------------------------------------------------- */
 433 char *pdkim_decode_qp(char *str) {
 434   int nchar = 0;
 435   char *q;
 436   char *p = str;
 437   char *n = malloc(strlen(p)+1);
 438   if (n == NULL) return NULL;
 439   *n = '\0';
 440   q = n;
 441   while (*p != '\0') {
 442     if (*p == '=') {
 443       p = pdkim_decode_qp_char(p,&nchar);
 444       if (nchar >= 0) {
 445         *q = nchar;
 446         q++;
 447         continue;
 448       }
 449     }
 450     else {
 451       *q = *p;
 452       q++;
 453     }
 454     p++;
 455   }
 456   *q = '\0';
 457   return n;
 458 }
 459
 460
 461 /* -------------------------------------------------------------------------- */
 462 char *pdkim_decode_base64(char *str, int *num_decoded) {
 463   int dlen = 0;
 464   char *res;
 465
 466   base64_decode(NULL, &dlen, (unsigned char *)str, strlen(str));
 467   res = malloc(dlen+1);
 468   if (res == NULL) return NULL;
 469   if (base64_decode((unsigned char *)res,&dlen,(unsigned char *)str,strlen(str)) != 0) {
 470     free(res);
 471     return NULL;
 472   }
 473   if (num_decoded != NULL) *num_decoded = dlen;
 474   return res;
 475 }
 476
 477 /* -------------------------------------------------------------------------- */
 478 char *pdkim_encode_base64(char *str, int num) {
 479   int dlen = 0;
 480   char *res;
 481
 482   base64_encode(NULL, &dlen, (unsigned char *)str, num);
 483   res = malloc(dlen+1);
 484   if (res == NULL) return NULL;
 485   if (base64_encode((unsigned char *)res,&dlen,(unsigned char *)str,num) != 0) {
 486     free(res);
 487     return NULL;
 488   }
 489   return res;
 490 }
 491
 492
 493 /* -------------------------------------------------------------------------- */
 494 #define PDKIM_HDR_LIMBO 0
 495 #define PDKIM_HDR_TAG   1
 496 #define PDKIM_HDR_VALUE 2
 497 pdkim_signature *pdkim_parse_sig_header(pdkim_ctx *ctx, char *raw_hdr) {
 498   pdkim_signature *sig ;
 499   char *p,*q;
 500   pdkim_str *cur_tag = NULL;
 501   pdkim_str *cur_val = NULL;
 502   int past_hname = 0;
 503   int in_b_val = 0;
 504   int where = PDKIM_HDR_LIMBO;
 505   int i;
 506
 507   sig = malloc(sizeof(pdkim_signature));
 508   if (sig == NULL) return NULL;
 509   memset(sig,0,sizeof(pdkim_signature));
 510   sig->bodylength = -1;
 511
 512   sig->rawsig_no_b_val = malloc(strlen(raw_hdr)+1);
 513   if (sig->rawsig_no_b_val == NULL) {
 514     free(sig);
 515     return NULL;
 516   }
 517
 518   p = raw_hdr;
 519   q = sig->rawsig_no_b_val;
 520
 521   while (1) {
 522
 523     /* Ignore FWS */
 524     if ( (*p == '\r') || (*p == '\n') )
 525       goto NEXT_CHAR;
 526
 527     /* Fast-forward through header name */
 528     if (!past_hname) {
 529       if (*p == ':') past_hname = 1;
 530       goto NEXT_CHAR;
 531     }
 532
 533     if (where == PDKIM_HDR_LIMBO) {
 534       /* In limbo, just wait for a tag-char to appear */
 535       if (!((*p >= 'a') && (*p <= 'z')))
 536         goto NEXT_CHAR;
 537
 538       where = PDKIM_HDR_TAG;
 539     }
 540
 541     if (where == PDKIM_HDR_TAG) {
 542       if (cur_tag == NULL)
 543         cur_tag = pdkim_strnew(NULL);
 544
 545       if ((*p >= 'a') && (*p <= 'z'))
 546         pdkim_strncat(cur_tag,p,1);
 547
 548       if (*p == '=') {
 549         if (strcmp(cur_tag->str,"b") == 0) {
 550           *q = '='; q++;
 551           in_b_val = 1;
 552         }
 553         where = PDKIM_HDR_VALUE;
 554         goto NEXT_CHAR;
 555       }
 556     }
 557
 558     if (where == PDKIM_HDR_VALUE) {
 559       if (cur_val == NULL)
 560         cur_val = pdkim_strnew(NULL);
 561
 562       if ( (*p == '\r') || (*p == '\n') || (*p == ' ') || (*p == '\t') )
 563         goto NEXT_CHAR;
 564
 565       if ( (*p == ';') || (*p == '\0') ) {
 566         if (cur_tag->len > 0) {
 567           pdkim_strtrim(cur_val);
 568           #ifdef PDKIM_DEBUG
 569           if (ctx->debug_stream)
 570             fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str);
 571           #endif
 572           switch (cur_tag->str[0]) {
 573             case 'b':
 574               switch (cur_tag->str[1]) {
 575                 case 'h':
 576                   sig->bodyhash = pdkim_decode_base64(cur_val->str,&(sig->bodyhash_len));
 577                 break;
 578                 default:
 579                   sig->sigdata = pdkim_decode_base64(cur_val->str,&(sig->sigdata_len));
 580                 break;
 581               }
 582             break;
 583             case 'v':
 584               if (strcmp(cur_val->str,PDKIM_SIGNATURE_VERSION) == 0) {
 585                 /* We only support version 1, and that is currently the
 586                    only version there is. */
 587                 sig->version = 1;
 588               }
 589             break;
 590             case 'a':
 591               i = 0;
 592               while (pdkim_algos[i] != NULL) {
 593                 if (strcmp(cur_val->str,pdkim_algos[i]) == 0 ) {
 594                   sig->algo = i;
 595                   break;
 596                 }
 597                 i++;
 598               }
 599             break;
 600             case 'c':
 601               i = 0;
 602               while (pdkim_combined_canons[i].str != NULL) {
 603                 if (strcmp(cur_val->str,pdkim_combined_canons[i].str) == 0 ) {
 604                   sig->canon_headers = pdkim_combined_canons[i].canon_headers;
 605                   sig->canon_body    = pdkim_combined_canons[i].canon_body;
 606                   break;
 607                 }
 608                 i++;
 609               }
 610             break;
 611             case 'q':
 612               i = 0;
 613               while (pdkim_querymethods[i] != NULL) {
 614                 if (strcmp(cur_val->str,pdkim_querymethods[i]) == 0 ) {
 615                   sig->querymethod = i;
 616                   break;
 617                 }
 618                 i++;
 619               }
 620             break;
 621             case 's':
 622               sig->selector = strdup(cur_val->str);
 623             break;
 624             case 'd':
 625               sig->domain = strdup(cur_val->str);
 626             break;
 627             case 'i':
 628               sig->identity = pdkim_decode_qp(cur_val->str);
 629             break;
 630             case 't':
 631               sig->created = strtoul(cur_val->str,NULL,10);
 632             break;
 633             case 'x':
 634               sig->expires = strtoul(cur_val->str,NULL,10);
 635             break;
 636             case 'l':
 637               sig->bodylength = strtol(cur_val->str,NULL,10);
 638             break;
 639             case 'h':
 640               sig->headernames = strdup(cur_val->str);
 641             break;
 642             case 'z':
 643               sig->copiedheaders = pdkim_decode_qp(cur_val->str);
 644             break;
 645             default:
 646               #ifdef PDKIM_DEBUG
 647               if (ctx->debug_stream)
 648                 fprintf(ctx->debug_stream, "Unknown tag encountered\n");
 649               #endif
 650             break;
 651           }
 652         }
 653         pdkim_strclear(cur_tag);
 654         pdkim_strclear(cur_val);
 655         in_b_val = 0;
 656         where = PDKIM_HDR_LIMBO;
 657         goto NEXT_CHAR;
 658       }
 659       else pdkim_strncat(cur_val,p,1);
 660     }
 661
 662     NEXT_CHAR:
 663     if (*p == '\0') break;
 664
 665     if (!in_b_val) {
 666       *q = *p;
 667       q++;
 668     }
 669     p++;
 670   }
 671
 672   /* Make sure the most important bits are there. */
 673   if (!(sig->domain      && (*(sig->domain)      != '\0') &&
 674         sig->selector    && (*(sig->selector)    != '\0') &&
 675         sig->headernames && (*(sig->headernames) != '\0') &&
 676         sig->bodyhash    &&
 677         sig->sigdata     &&
 678         sig->version)) {
 679     pdkim_free_sig(sig);
 680     return NULL;
 681   }
 682
 683   /* Copy header list to 'tick-off' header list */
 684   sig->hnames_check = strdup(sig->headernames);
 685
 686   *q = '\0';
 687   /* Chomp raw header. The final newline must not be added to the signature. */
 688   q--;
 689   while( (q > sig->rawsig_no_b_val) && ((*q == '\r') || (*q == '\n')) ) {
 690     *q = '\0'; q--;
 691   }
 692
 693   #ifdef PDKIM_DEBUG
 694   if (ctx->debug_stream) {
 695     fprintf(ctx->debug_stream,
 696             "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
 697     pdkim_quoteprint(ctx->debug_stream,
 698                      sig->rawsig_no_b_val,
 699                      strlen(sig->rawsig_no_b_val), 1);
 700     fprintf(ctx->debug_stream,
 701             "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
 702   }
 703   #endif
 704
 705   sig->sha1_body = malloc(sizeof(sha1_context));
 706   if (sig->sha1_body == NULL) {
 707     pdkim_free_sig(sig);
 708     return NULL;
 709   }
 710   sig->sha2_body = malloc(sizeof(sha2_context));
 711   if (sig->sha2_body == NULL) {
 712     pdkim_free_sig(sig);
 713     return NULL;
 714   }
 715
 716   sha1_starts(sig->sha1_body);
 717   sha2_starts(sig->sha2_body,0);
 718
 719   return sig;
 720 }
 721
 722
 723 /* -------------------------------------------------------------------------- */
 724 pdkim_pubkey *pdkim_parse_pubkey_record(pdkim_ctx *ctx, char *raw_record) {
 725   pdkim_pubkey *pub ;
 726   char *p;
 727   pdkim_str *cur_tag = NULL;
 728   pdkim_str *cur_val = NULL;
 729   int where = PDKIM_HDR_LIMBO;
 730
 731   pub = malloc(sizeof(pdkim_pubkey));
 732   if (pub == NULL) return NULL;
 733   memset(pub,0,sizeof(pdkim_pubkey));
 734
 735   p = raw_record;
 736
 737   while (1) {
 738
 739     /* Ignore FWS */
 740     if ( (*p == '\r') || (*p == '\n') )
 741       goto NEXT_CHAR;
 742
 743     if (where == PDKIM_HDR_LIMBO) {
 744       /* In limbo, just wait for a tag-char to appear */
 745       if (!((*p >= 'a') && (*p <= 'z')))
 746         goto NEXT_CHAR;
 747
 748       where = PDKIM_HDR_TAG;
 749     }
 750
 751     if (where == PDKIM_HDR_TAG) {
 752       if (cur_tag == NULL)
 753         cur_tag = pdkim_strnew(NULL);
 754
 755       if ((*p >= 'a') && (*p <= 'z'))
 756         pdkim_strncat(cur_tag,p,1);
 757
 758       if (*p == '=') {
 759         where = PDKIM_HDR_VALUE;
 760         goto NEXT_CHAR;
 761       }
 762     }
 763
 764     if (where == PDKIM_HDR_VALUE) {
 765       if (cur_val == NULL)
 766         cur_val = pdkim_strnew(NULL);
 767
 768       if ( (*p == '\r') || (*p == '\n') )
 769         goto NEXT_CHAR;
 770
 771       if ( (*p == ';') || (*p == '\0') ) {
 772         if (cur_tag->len > 0) {
 773           pdkim_strtrim(cur_val);
 774           #ifdef PDKIM_DEBUG
 775           if (ctx->debug_stream)
 776             fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str);
 777           #endif
 778           switch (cur_tag->str[0]) {
 779             case 'v':
 780               /* This tag isn't evaluated because:
 781                  - We only support version DKIM1.
 782                  - Which is the default for this value (set below)
 783                  - Other versions are currently not specified.      */
 784             break;
 785             case 'h':
 786               pub->hashes = strdup(cur_val->str);
 787             break;
 788             case 'g':
 789               pub->granularity = strdup(cur_val->str);
 790             break;
 791             case 'n':
 792               pub->notes = pdkim_decode_qp(cur_val->str);
 793             break;
 794             case 'p':
 795               pub->key = pdkim_decode_base64(cur_val->str,&(pub->key_len));
 796             break;
 797             case 'k':
 798               pub->hashes = strdup(cur_val->str);
 799             break;
 800             case 's':
 801               pub->srvtype = strdup(cur_val->str);
 802             break;
 803             case 't':
 804               if (strchr(cur_val->str,'t') != NULL) pub->testing = 1;
 805               if (strchr(cur_val->str,'s') != NULL) pub->no_subdomaining = 1;
 806             break;
 807             default:
 808               #ifdef PDKIM_DEBUG
 809               if (ctx->debug_stream)
 810                 fprintf(ctx->debug_stream, "Unknown tag encountered\n");
 811               #endif
 812             break;
 813           }
 814         }
 815         pdkim_strclear(cur_tag);
 816         pdkim_strclear(cur_val);
 817         where = PDKIM_HDR_LIMBO;
 818         goto NEXT_CHAR;
 819       }
 820       else pdkim_strncat(cur_val,p,1);
 821     }
 822
 823     NEXT_CHAR:
 824     if (*p == '\0') break;
 825     p++;
 826   }
 827
 828   /* Set fallback defaults */
 829   if (pub->version     == NULL) pub->version     = strdup(PDKIM_PUB_RECORD_VERSION);
 830   if (pub->granularity == NULL) pub->granularity = strdup("*");
 831   if (pub->keytype     == NULL) pub->keytype     = strdup("rsa");
 832   if (pub->srvtype     == NULL) pub->srvtype     = strdup("*");
 833
 834   /* p= is required */
 835   if (pub->key == NULL) {
 836     pdkim_free_pubkey(pub);
 837     return NULL;
 838   }
 839
 840   return pub;
 841 }
 842
 843
 844 /* -------------------------------------------------------------------------- */
 845 int pdkim_update_bodyhash(pdkim_ctx *ctx, char *data, int len) {
 846   pdkim_signature *sig = ctx->sig;
 847   /* Cache relaxed version of data */
 848   char *relaxed_data = NULL;
 849   int   relaxed_len  = 0;
 850
 851   /* Traverse all signatures, updating their hashes. */
 852   while (sig != NULL) {
 853     /* Defaults to simple canon (no further treatment necessary) */
 854     char *canon_data = data;
 855     int   canon_len = len;
 856
 857     if (sig->canon_body == PDKIM_CANON_RELAXED) {
 858       /* Relax the line if not done already */
 859       if (relaxed_data == NULL) {
 860         int seen_wsp = 0;
 861         char *p = data;
 862         int q = 0;
 863         relaxed_data = malloc(len+1);
 864         if (relaxed_data == NULL) return PDKIM_ERR_OOM;
 865         while (*p != '\0') {
 866           char c = *p;
 867           if (c == '\r') {
 868             if ( (q > 0) && (relaxed_data[q-1] == ' ') ) q--;
 869           }
 870           else if ( (c == '\t') || (c == ' ') ) {
 871             c = ' '; /* Turns WSP into SP */
 872             if (seen_wsp) {
 873               p++;
 874               continue;
 875             }
 876             else seen_wsp = 1;
 877           }
 878           else seen_wsp = 0;
 879           relaxed_data[q++] = c;
 880           p++;
 881         }
 882         relaxed_data[q] = '\0';
 883         relaxed_len = q;
 884       }
 885       canon_data = relaxed_data;
 886       canon_len  = relaxed_len;
 887     }
 888
 889     /* Make sure we don't exceed the to-be-signed body length */
 890     if ((sig->bodylength >= 0) &&
 891         ((sig->signed_body_bytes+(unsigned long)canon_len) > sig->bodylength))
 892       canon_len = (sig->bodylength - sig->signed_body_bytes);
 893
 894     if (canon_len > 0) {
 895       if (sig->algo == PDKIM_ALGO_RSA_SHA1)
 896         sha1_update(sig->sha1_body,(unsigned char *)canon_data,canon_len);
 897       else
 898         sha2_update(sig->sha2_body,(unsigned char *)canon_data,canon_len);
 899       sig->signed_body_bytes += canon_len;
 900 #ifdef PDKIM_DEBUG
 901       if (ctx->debug_stream!=NULL)
 902         pdkim_quoteprint(ctx->debug_stream,canon_data,canon_len,0);
 903 #endif
 904     }
 905
 906     sig = sig->next;
 907   }
 908
 909   if (relaxed_data != NULL) free(relaxed_data);
 910   return PDKIM_OK;
 911 }
 912
 913
 914 /* -------------------------------------------------------------------------- */
 915 int pdkim_finish_bodyhash(pdkim_ctx *ctx) {
 916   pdkim_signature *sig = ctx->sig;
 917
 918   /* Traverse all signatures */
 919   while (sig != NULL) {
 920
 921     /* Finish hashes */
 922     unsigned char bh[32]; /* SHA-256 = 32 Bytes,  SHA-1 = 20 Bytes */
 923     if (sig->algo == PDKIM_ALGO_RSA_SHA1)
 924       sha1_finish(sig->sha1_body,bh);
 925     else
 926       sha2_finish(sig->sha2_body,bh);
 927
 928     #ifdef PDKIM_DEBUG
 929     if (ctx->debug_stream) {
 930       fprintf(ctx->debug_stream, "PDKIM [%s] Body bytes hashed: %lu\n",
 931         sig->domain, sig->signed_body_bytes);
 932       fprintf(ctx->debug_stream, "PDKIM [%s] bh  computed: ", sig->domain);
 933       pdkim_hexprint(ctx->debug_stream, (char *)bh,
 934                      (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1);
 935     }
 936     #endif
 937
 938     /* SIGNING -------------------------------------------------------------- */
 939     if (ctx->mode == PDKIM_MODE_SIGN) {
 940       sig->bodyhash_len = (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32;
 941       sig->bodyhash = malloc(sig->bodyhash_len);
 942       if (sig->bodyhash == NULL) return PDKIM_ERR_OOM;
 943       memcpy(sig->bodyhash,bh,sig->bodyhash_len);
 944
 945       /* If bodylength limit is set, and we have received less bytes
 946          than the requested amount, effectively remove the limit tag. */
 947       if (sig->signed_body_bytes < sig->bodylength) sig->bodylength = -1;
 948     }
 949     /* VERIFICATION --------------------------------------------------------- */
 950     else {
 951       /* Compare bodyhash */
 952       if (memcmp(bh,sig->bodyhash,
 953                  (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32) == 0) {
 954         #ifdef PDKIM_DEBUG
 955         if (ctx->debug_stream)
 956           fprintf(ctx->debug_stream, "PDKIM [%s] Body hash verified OK\n",
 957                   sig->domain);
 958         #endif
 959       }
 960       else {
 961         #ifdef PDKIM_DEBUG
 962         if (ctx->debug_stream) {
 963           fprintf(ctx->debug_stream, "PDKIM [%s] Body hash did NOT verify\n",
 964                   sig->domain);
 965           fprintf(ctx->debug_stream, "PDKIM [%s] bh signature: ", sig->domain);
 966           pdkim_hexprint(ctx->debug_stream, sig->bodyhash,
 967                            (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1);
 968         }
 969         #endif
 970         sig->verify_status     = PDKIM_VERIFY_FAIL;
 971         sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY;
 972       }
 973     }
 974
 975     sig = sig->next;
 976   }
 977
 978   return PDKIM_OK;
 979 }
 980
 981
 982
 983 /* -------------------------------------------------------------------------- */
 984 /* Callback from pdkim_feed below for processing complete body lines */
 985 int pdkim_bodyline_complete(pdkim_ctx *ctx) {
 986   char *p = ctx->linebuf;
 987   int   n = ctx->linebuf_offset;
 988
 989   /* Ignore extra data if we've seen the end-of-data marker */
 990   if (ctx->seen_eod) goto BAIL;
 991
 992   /* We've always got one extra byte to stuff a zero ... */
 993   ctx->linebuf[(ctx->linebuf_offset)] = '\0';
 994
 995   if (ctx->input_mode == PDKIM_INPUT_SMTP) {
 996     /* Terminate on EOD marker */
 997     if (memcmp(p,".\r\n",3) == 0) {
 998       ctx->seen_eod = 1;
 999       goto BAIL;
1000     }
1001     /* Unstuff dots */
1002     if (memcmp(p,"..",2) == 0) {
1003       p++;
1004       n--;
1005     }
1006   }
1007
1008   /* Empty lines need to be buffered until we find a non-empty line */
1009   if (memcmp(p,"\r\n",2) == 0) {
1010     ctx->num_buffered_crlf++;
1011     goto BAIL;
1012   }
1013
1014   /* At this point, we have a non-empty line, so release the buffered ones. */
1015   while (ctx->num_buffered_crlf) {
1016     pdkim_update_bodyhash(ctx,"\r\n",2);
1017     ctx->num_buffered_crlf--;
1018   }
1019
1020   pdkim_update_bodyhash(ctx,p,n);
1021
1022   BAIL:
1023   ctx->linebuf_offset = 0;
1024   return PDKIM_OK;
1025 }
1026
1027
1028 /* -------------------------------------------------------------------------- */
1029 /* Callback from pdkim_feed below for processing complete headers */
1030 #define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:"
1031 int pdkim_header_complete(pdkim_ctx *ctx) {
1032   pdkim_signature *sig = ctx->sig;
1033
1034   /* Special case: The last header can have an extra \r appended */
1035   if ( (ctx->cur_header->len > 1) &&
1036        (ctx->cur_header->str[(ctx->cur_header->len)-1] == '\r') ) {
1037     ctx->cur_header->str[(ctx->cur_header->len)-1] = '\0';
1038     ctx->cur_header->len--;
1039   }
1040
1041   ctx->num_headers++;
1042   if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
1043
1044   /* Traverse all signatures */
1045   while (sig != NULL) {
1046     pdkim_stringlist *list;
1047
1048     /* SIGNING -------------------------------------------------------------- */
1049     if (ctx->mode == PDKIM_MODE_SIGN) {
1050       if (header_name_match(ctx->cur_header->str,
1051                             sig->sign_headers?
1052                               sig->sign_headers:
1053                               PDKIM_DEFAULT_SIGN_HEADERS, 0) != PDKIM_OK) goto NEXT_SIG;
1054     }
1055     /* VERIFICATION --------------------------------------------------------- */
1056     else {
1057       /* Header is not included or all instances were already 'ticked off' */
1058       if (header_name_match(ctx->cur_header->str,
1059                             sig->hnames_check, 1) != PDKIM_OK) goto NEXT_SIG;
1060     }
1061
1062     /* Add header to the signed headers list (in reverse order) */
1063     list = pdkim_prepend_stringlist(sig->headers,
1064                                     ctx->cur_header->str);
1065     if (list == NULL) return PDKIM_ERR_OOM;
1066     sig->headers = list;
1067
1068     NEXT_SIG:
1069     sig = sig->next;
1070   }
1071
1072   /* DKIM-Signature: headers are added to the verification list */
1073   if ( (ctx->mode == PDKIM_MODE_VERIFY) &&
1074        (strncasecmp(ctx->cur_header->str,
1075                     DKIM_SIGNATURE_HEADERNAME,
1076                     strlen(DKIM_SIGNATURE_HEADERNAME)) == 0) ) {
1077      pdkim_signature *new_sig;
1078     /* Create and chain new signature block */
1079     #ifdef PDKIM_DEBUG
1080     if (ctx->debug_stream)
1081       fprintf(ctx->debug_stream,
1082         "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1083     #endif
1084     new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header->str);
1085     if (new_sig != NULL) {
1086       pdkim_signature *last_sig = ctx->sig;
1087       if (last_sig == NULL) {
1088         ctx->sig = new_sig;
1089       }
1090       else {
1091         while (last_sig->next != NULL) { last_sig = last_sig->next; }
1092         last_sig->next = new_sig;
1093       }
1094     }
1095     else {
1096       #ifdef PDKIM_DEBUG
1097       if (ctx->debug_stream) {
1098         fprintf(ctx->debug_stream,"Error while parsing signature header\n");
1099         fprintf(ctx->debug_stream,
1100           "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1101       }
1102       #endif
1103     }
1104   }
1105
1106   BAIL:
1107   pdkim_strclear(ctx->cur_header); /* Re-use existing pdkim_str */
1108   return PDKIM_OK;
1109 }
1110
1111
1112
1113 /* -------------------------------------------------------------------------- */
1114 #define HEADER_BUFFER_FRAG_SIZE 256
1115 DLLEXPORT int pdkim_feed (pdkim_ctx *ctx,
1116                 char *data,
1117                 int   len) {
1118   int p;
1119   for (p=0;p<len;p++) {
1120     char c = data[p];
1121     if (ctx->past_headers) {
1122       /* Processing body byte */
1123       ctx->linebuf[(ctx->linebuf_offset)++] = c;
1124       if (c == '\n') {
1125         int rc = pdkim_bodyline_complete(ctx); /* End of line */
1126         if (rc != PDKIM_OK) return rc;
1127       }
1128       if (ctx->linebuf_offset == (PDKIM_MAX_BODY_LINE_LEN-1))
1129         return PDKIM_ERR_LONG_LINE;
1130     }
1131     else {
1132       /* Processing header byte */
1133       if (c != '\r') {
1134         if (c == '\n') {
1135           if (ctx->seen_lf) {
1136             int rc = pdkim_header_complete(ctx); /* Seen last header line */
1137             if (rc != PDKIM_OK) return rc;
1138             ctx->past_headers = 1;
1139             ctx->seen_lf = 0;
1140 #ifdef PDKIM_DEBUG
1141             if (ctx->debug_stream)
1142               fprintf(ctx->debug_stream,
1143                 "PDKIM >> Hashed body data, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1144 #endif
1145             continue;
1146           }
1147           else ctx->seen_lf = 1;
1148         }
1149         else if (ctx->seen_lf) {
1150           if (! ((c == '\t') || (c == ' '))) {
1151             int rc = pdkim_header_complete(ctx); /* End of header */
1152             if (rc != PDKIM_OK) return rc;
1153           }
1154           ctx->seen_lf = 0;
1155         }
1156       }
1157       if (ctx->cur_header == NULL) {
1158         ctx->cur_header = pdkim_strnew(NULL);
1159         if (ctx->cur_header == NULL) return PDKIM_ERR_OOM;
1160       }
1161       if (ctx->cur_header->len < PDKIM_MAX_HEADER_LEN)
1162         if (pdkim_strncat(ctx->cur_header,&data[p],1) == NULL)
1163           return PDKIM_ERR_OOM;
1164     }
1165   }
1166   return PDKIM_OK;
1167 }
1168
1169
1170 /* -------------------------------------------------------------------------- */
1171 char *pdkim_create_header(pdkim_signature *sig, int final) {
1172   char *rc = NULL;
1173   char *base64_bh = NULL;
1174   char *base64_b  = NULL;
1175   pdkim_str *hdr = pdkim_strnew("DKIM-Signature: v="PDKIM_SIGNATURE_VERSION);
1176   if (hdr == NULL) return NULL;
1177
1178   base64_bh = pdkim_encode_base64(sig->bodyhash, sig->bodyhash_len);
1179   if (base64_bh == NULL) goto BAIL;
1180
1181   /* Required and static bits */
1182   if (
1183         pdkim_strcat(hdr,"; a=")                                &&
1184         pdkim_strcat(hdr,pdkim_algos[sig->algo])                &&
1185         pdkim_strcat(hdr,"; q=")                                &&
1186         pdkim_strcat(hdr,pdkim_querymethods[sig->querymethod])  &&
1187         pdkim_strcat(hdr,"; c=")                                &&
1188         pdkim_strcat(hdr,pdkim_canons[sig->canon_headers])      &&
1189         pdkim_strcat(hdr,"/")                                   &&
1190         pdkim_strcat(hdr,pdkim_canons[sig->canon_body])         &&
1191         pdkim_strcat(hdr,"; d=")                                &&
1192         pdkim_strcat(hdr,sig->domain)                           &&
1193         pdkim_strcat(hdr,"; s=")                                &&
1194         pdkim_strcat(hdr,sig->selector)                         &&
1195         pdkim_strcat(hdr,";\r\n\th=")                           &&
1196         pdkim_strcat(hdr,sig->headernames)                      &&
1197         pdkim_strcat(hdr,"; bh=")                               &&
1198         pdkim_strcat(hdr,base64_bh)                             &&
1199         pdkim_strcat(hdr,";\r\n\t")
1200      ) {
1201     /* Optional bits */
1202     if (sig->identity != NULL) {
1203       if (!( pdkim_strcat(hdr,"i=")                             &&
1204              pdkim_strcat(hdr,sig->identity)                    &&
1205              pdkim_strcat(hdr,";") ) ) {
1206         goto BAIL;
1207       }
1208     }
1209     if (sig->created > 0) {
1210       if (!( pdkim_strcat(hdr,"t=")                             &&
1211              pdkim_numcat(hdr,sig->created)                     &&
1212              pdkim_strcat(hdr,";") ) ) {
1213         goto BAIL;
1214       }
1215     }
1216     if (sig->expires > 0) {
1217       if (!( pdkim_strcat(hdr,"x=")                             &&
1218              pdkim_numcat(hdr,sig->expires)                     &&
1219              pdkim_strcat(hdr,";") ) ) {
1220         goto BAIL;
1221       }
1222     }
1223     if (sig->bodylength >= 0) {
1224       if (!( pdkim_strcat(hdr,"l=")                             &&
1225              pdkim_numcat(hdr,sig->bodylength)                  &&
1226              pdkim_strcat(hdr,";") ) ) {
1227         goto BAIL;
1228       }
1229     }
1230     /* Extra linebreak */
1231     if (hdr->str[(hdr->len)-1] == ';') {
1232       if (!pdkim_strcat(hdr," \r\n\t")) goto BAIL;
1233     }
1234     /* Preliminary or final version? */
1235     if (final) {
1236       base64_b = pdkim_encode_base64(sig->sigdata, sig->sigdata_len);
1237       if (base64_b == NULL) goto BAIL;
1238       if (
1239             pdkim_strcat(hdr,"b=")                              &&
1240             pdkim_strcat(hdr,base64_b)                          &&
1241             pdkim_strcat(hdr,";")
1242          ) goto DONE;
1243     }
1244     else {
1245       if (pdkim_strcat(hdr,"b=;")) goto DONE;
1246     }
1247
1248     goto BAIL;
1249   }
1250
1251   DONE:
1252   rc = strdup(hdr->str);
1253
1254   BAIL:
1255   pdkim_strfree(hdr);
1256   if (base64_bh != NULL) free(base64_bh);
1257   if (base64_b  != NULL) free(base64_b);
1258   return rc;
1259 }
1260
1261
1262 /* -------------------------------------------------------------------------- */
1263 DLLEXPORT int pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures) {
1264   pdkim_signature *sig = ctx->sig;
1265   pdkim_str *headernames = NULL;             /* Collected signed header names */
1266
1267   /* Check if we must still flush a (partial) header. If that is the
1268      case, the message has no body, and we must compute a body hash
1269      out of '<CR><LF>' */
1270   if (ctx->cur_header->len) {
1271     int rc = pdkim_header_complete(ctx);
1272     if (rc != PDKIM_OK) return rc;
1273     pdkim_update_bodyhash(ctx,"\r\n",2);
1274   }
1275   else {
1276     /* For non-smtp input, check if there's an unfinished line in the
1277        body line buffer. If that is the case, we must add a CRLF to the
1278        hash to properly terminate the message. */
1279     if ((ctx->input_mode == PDKIM_INPUT_NORMAL) && ctx->linebuf_offset) {
1280       pdkim_update_bodyhash(ctx, ctx->linebuf, ctx->linebuf_offset);
1281       pdkim_update_bodyhash(ctx,"\r\n",2);
1282     }
1283     #ifdef PDKIM_DEBUG
1284     if (ctx->debug_stream)
1285       fprintf(ctx->debug_stream,
1286         "\nPDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1287     #endif
1288   }
1289
1290   /* Build (and/or evaluate) body hash */
1291   if (pdkim_finish_bodyhash(ctx) != PDKIM_OK) return PDKIM_ERR_OOM;
1292
1293   /* SIGNING -------------------------------------------------------------- */
1294   if (ctx->mode == PDKIM_MODE_SIGN) {
1295     headernames = pdkim_strnew(NULL);
1296     if (headernames == NULL) return PDKIM_ERR_OOM;
1297   }
1298   /* ---------------------------------------------------------------------- */
1299
1300   while (sig != NULL) {
1301     sha1_context sha1_headers;
1302     sha2_context sha2_headers;
1303     char *sig_hdr;
1304     char headerhash[32];
1305
1306     if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1307       sha1_starts(&sha1_headers);
1308     else
1309       sha2_starts(&sha2_headers,0);
1310
1311     #ifdef PDKIM_DEBUG
1312     if (ctx->debug_stream)
1313       fprintf(ctx->debug_stream,
1314               "PDKIM >> Hashed header data, canonicalized, in sequence >>>>>>>>>>>>>>\n");
1315     #endif
1316
1317     /* SIGNING ---------------------------------------------------------------- */
1318     /* When signing, walk through our header list and add them to the hash. As we
1319        go, construct a list of the header's names to use for the h= parameter. */
1320     if (ctx->mode == PDKIM_MODE_SIGN) {
1321       pdkim_stringlist *p = sig->headers;
1322       while (p != NULL) {
1323         char *rh = NULL;
1324         /* Collect header names (Note: colon presence is guaranteed here) */
1325         char *q = strchr(p->value,':');
1326         if (pdkim_strncat(headernames, p->value,
1327                           (q-(p->value))+((p->next==NULL)?0:1)) == NULL)
1328           return PDKIM_ERR_OOM;
1329
1330         if (sig->canon_headers == PDKIM_CANON_RELAXED)
1331           rh = pdkim_relax_header(p->value,1); /* cook header for relaxed canon */
1332         else
1333           rh = strdup(p->value);               /* just copy it for simple canon */
1334
1335         if (rh == NULL) return PDKIM_ERR_OOM;
1336
1337         /* Feed header to the hash algorithm */
1338         if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1339           sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh));
1340         else
1341           sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh));
1342         #ifdef PDKIM_DEBUG
1343         if (ctx->debug_stream)
1344           pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1);
1345         #endif
1346         free(rh);
1347         p = p->next;
1348       }
1349     }
1350     /* VERIFICATION ----------------------------------------------------------- */
1351     /* When verifying, walk through the header name list in the h= parameter and
1352        add the headers to the hash in that order. */
1353     else {
1354       char *b = strdup(sig->headernames);
1355       char *p = b;
1356       char *q = NULL;
1357       if (b == NULL) return PDKIM_ERR_OOM;
1358
1359       while(1) {
1360         pdkim_stringlist *hdrs = sig->headers;
1361         q = strchr(p,':');
1362         if (q != NULL) *q = '\0';
1363         while (hdrs != NULL) {
1364           if ( (strncasecmp(hdrs->value,p,strlen(p)) == 0) &&
1365                ((hdrs->value)[strlen(p)] == ':') ) {
1366             char *rh = NULL;
1367             if (sig->canon_headers == PDKIM_CANON_RELAXED)
1368               rh = pdkim_relax_header(hdrs->value,1); /* cook header for relaxed canon */
1369             else
1370               rh = strdup(hdrs->value);               /* just copy it for simple canon */
1371             if (rh == NULL) return PDKIM_ERR_OOM;
1372             /* Feed header to the hash algorithm */
1373             if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1374               sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh));
1375             else
1376               sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh));
1377             #ifdef PDKIM_DEBUG
1378             if (ctx->debug_stream)
1379               pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1);
1380             #endif
1381             free(rh);
1382             (hdrs->value)[0] = '_';
1383             break;
1384           }
1385           hdrs = hdrs->next;
1386         }
1387         if (q == NULL) break;
1388         p = q+1;
1389       }
1390       free(b);
1391     }
1392
1393     #ifdef PDKIM_DEBUG
1394     if (ctx->debug_stream)
1395       fprintf(ctx->debug_stream,
1396               "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1397     #endif
1398
1399     /* SIGNING ---------------------------------------------------------------- */
1400     if (ctx->mode == PDKIM_MODE_SIGN) {
1401       /* Copy headernames to signature struct */
1402       sig->headernames = strdup(headernames->str);
1403       pdkim_strfree(headernames);
1404
1405       /* Create signature header with b= omitted */
1406       sig_hdr = pdkim_create_header(ctx->sig,0);
1407     }
1408     /* VERIFICATION ----------------------------------------------------------- */
1409     else {
1410       sig_hdr = strdup(sig->rawsig_no_b_val);
1411     }
1412     /* ------------------------------------------------------------------------ */
1413
1414     if (sig_hdr == NULL) return PDKIM_ERR_OOM;
1415
1416     /* Relax header if necessary */
1417     if (sig->canon_headers == PDKIM_CANON_RELAXED) {
1418       char *relaxed_hdr = pdkim_relax_header(sig_hdr,0);
1419       free(sig_hdr);
1420       if (relaxed_hdr == NULL) return PDKIM_ERR_OOM;
1421       sig_hdr = relaxed_hdr;
1422     }
1423
1424     #ifdef PDKIM_DEBUG
1425     if (ctx->debug_stream) {
1426       fprintf(ctx->debug_stream,
1427               "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
1428       pdkim_quoteprint(ctx->debug_stream, sig_hdr, strlen(sig_hdr), 1);
1429       fprintf(ctx->debug_stream,
1430               "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1431     }
1432     #endif
1433
1434     /* Finalize header hash */
1435     if (sig->algo == PDKIM_ALGO_RSA_SHA1) {
1436       sha1_update(&(sha1_headers),(unsigned char *)sig_hdr,strlen(sig_hdr));
1437       sha1_finish(&(sha1_headers),(unsigned char *)headerhash);
1438       #ifdef PDKIM_DEBUG
1439       if (ctx->debug_stream) {
1440         fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain);
1441         pdkim_hexprint(ctx->debug_stream, headerhash, 20, 1);
1442       }
1443       #endif
1444     }
1445     else {
1446       sha2_update(&(sha2_headers),(unsigned char *)sig_hdr,strlen(sig_hdr));
1447       sha2_finish(&(sha2_headers),(unsigned char *)headerhash);
1448       #ifdef PDKIM_DEBUG
1449       if (ctx->debug_stream) {
1450         fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain);
1451         pdkim_hexprint(ctx->debug_stream, headerhash, 32, 1);
1452       }
1453       #endif
1454     }
1455
1456     free(sig_hdr);
1457
1458     /* SIGNING ---------------------------------------------------------------- */
1459     if (ctx->mode == PDKIM_MODE_SIGN) {
1460       rsa_context rsa;
1461
1462       rsa_init(&rsa,RSA_PKCS_V15,0,NULL,NULL);
1463
1464       /* Perform private key operation */
1465       if (rsa_parse_key(&rsa, (unsigned char *)sig->rsa_privkey,
1466                         strlen(sig->rsa_privkey), NULL, 0) != 0) {
1467         return PDKIM_ERR_RSA_PRIVKEY;
1468       }
1469
1470       sig->sigdata_len = mpi_size(&(rsa.N));
1471       sig->sigdata = malloc(sig->sigdata_len);
1472       if (sig->sigdata == NULL) return PDKIM_ERR_OOM;
1473
1474       if (rsa_pkcs1_sign( &rsa, RSA_PRIVATE,
1475                           ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1476                              RSA_SHA1:RSA_SHA256),
1477                           0,
1478                           (unsigned char *)headerhash,
1479                           (unsigned char *)sig->sigdata ) != 0) {
1480         return PDKIM_ERR_RSA_SIGNING;
1481       }
1482
1483       rsa_free(&rsa);
1484
1485       #ifdef PDKIM_DEBUG
1486       if (ctx->debug_stream) {
1487         fprintf(ctx->debug_stream, "PDKIM [%s] b computed: ",
1488                 sig->domain);
1489         pdkim_hexprint(ctx->debug_stream, sig->sigdata, sig->sigdata_len, 1);
1490       }
1491       #endif
1492
1493       sig->signature_header = pdkim_create_header(ctx->sig,1);
1494       if (sig->signature_header == NULL) return PDKIM_ERR_OOM;
1495     }
1496     /* VERIFICATION ----------------------------------------------------------- */
1497     else {
1498       rsa_context rsa;
1499       char *dns_txt_name, *dns_txt_reply;
1500
1501       rsa_init(&rsa,RSA_PKCS_V15,0,NULL,NULL);
1502
1503       dns_txt_name  = malloc(PDKIM_DNS_TXT_MAX_NAMELEN);
1504       if (dns_txt_name == NULL) return PDKIM_ERR_OOM;
1505       dns_txt_reply = malloc(PDKIM_DNS_TXT_MAX_RECLEN);
1506       if (dns_txt_reply == NULL) {
1507         free(dns_txt_name);
1508         return PDKIM_ERR_OOM;
1509       }
1510       memset(dns_txt_reply,0,PDKIM_DNS_TXT_MAX_RECLEN);
1511       memset(dns_txt_name ,0,PDKIM_DNS_TXT_MAX_NAMELEN);
1512
1513       if (snprintf(dns_txt_name,PDKIM_DNS_TXT_MAX_NAMELEN,
1514                    "%s._domainkey.%s.",
1515                    sig->selector,sig->domain) >= PDKIM_DNS_TXT_MAX_NAMELEN) {
1516         sig->verify_status =      PDKIM_VERIFY_INVALID;
1517         sig->verify_ext_status =  PDKIM_VERIFY_INVALID_BUFFER_SIZE;
1518         goto NEXT_VERIFY;
1519       }
1520
1521       if ((ctx->dns_txt_callback(dns_txt_name, dns_txt_reply) != PDKIM_OK) ||
1522           (dns_txt_reply[0] == '\0')) {
1523         sig->verify_status =      PDKIM_VERIFY_INVALID;
1524         sig->verify_ext_status =  PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
1525         goto NEXT_VERIFY;
1526       }
1527
1528       #ifdef PDKIM_DEBUG
1529       if (ctx->debug_stream) {
1530         fprintf(ctx->debug_stream,
1531                 "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1532         fprintf(ctx->debug_stream,"Raw record: ");
1533         pdkim_quoteprint(ctx->debug_stream, dns_txt_reply, strlen(dns_txt_reply), 1);
1534       }
1535       #endif
1536
1537       sig->pubkey = pdkim_parse_pubkey_record(ctx,dns_txt_reply);
1538       if (sig->pubkey == NULL) {
1539         sig->verify_status =      PDKIM_VERIFY_INVALID;
1540         sig->verify_ext_status =  PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1541         #ifdef PDKIM_DEBUG
1542         if (ctx->debug_stream) {
1543           fprintf(ctx->debug_stream,"Error while parsing public key record\n");
1544           fprintf(ctx->debug_stream,
1545             "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1546         }
1547         #endif
1548         goto NEXT_VERIFY;
1549       }
1550
1551       #ifdef PDKIM_DEBUG
1552       if (ctx->debug_stream) {
1553         fprintf(ctx->debug_stream,
1554           "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1555       }
1556       #endif
1557
1558       if (rsa_parse_public_key(&rsa,
1559                               (unsigned char *)sig->pubkey->key,
1560                                sig->pubkey->key_len) != 0) {
1561         sig->verify_status =      PDKIM_VERIFY_INVALID;
1562         sig->verify_ext_status =  PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1563         goto NEXT_VERIFY;
1564       }
1565
1566       /* Check the signature */
1567       if (rsa_pkcs1_verify(&rsa,
1568                         RSA_PUBLIC,
1569                         ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1570                              RSA_SHA1:RSA_SHA256),
1571                         0,
1572                         (unsigned char *)headerhash,
1573                         (unsigned char *)sig->sigdata) != 0) {
1574         sig->verify_status =      PDKIM_VERIFY_FAIL;
1575         sig->verify_ext_status =  PDKIM_VERIFY_FAIL_MESSAGE;
1576         #ifdef PDKIM_DEBUG
1577         if (ctx->debug_stream) {
1578           fprintf(ctx->debug_stream, "PDKIM [%s] signature did NOT verify OK\n",
1579                   sig->domain);
1580         }
1581         #endif
1582         goto NEXT_VERIFY;
1583       }
1584
1585       /* We have a winner! */
1586       sig->verify_status = PDKIM_VERIFY_PASS;
1587
1588       #ifdef PDKIM_DEBUG
1589       if (ctx->debug_stream) {
1590         fprintf(ctx->debug_stream, "PDKIM [%s] signature verified OK\n",
1591                 sig->domain);
1592       }
1593       #endif
1594
1595       NEXT_VERIFY:
1596       rsa_free(&rsa);
1597       free(dns_txt_name);
1598       free(dns_txt_reply);
1599     }
1600
1601     sig = sig->next;
1602   }
1603
1604   /* If requested, set return pointer to signature(s) */
1605   if (return_signatures != NULL) {
1606     *return_signatures = ctx->sig;
1607   }
1608
1609   return PDKIM_OK;
1610 }
1611
1612
1613 /* -------------------------------------------------------------------------- */
1614 DLLEXPORT pdkim_ctx *pdkim_init_verify(int input_mode,
1615                              int(*dns_txt_callback)(char *, char *)
1616                              ) {
1617   pdkim_ctx *ctx = malloc(sizeof(pdkim_ctx));
1618   if (ctx == NULL) return NULL;
1619   memset(ctx,0,sizeof(pdkim_ctx));
1620
1621   ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN);
1622   if (ctx->linebuf == NULL) {
1623     free(ctx);
1624     return NULL;
1625   }
1626
1627   ctx->mode = PDKIM_MODE_VERIFY;
1628   ctx->input_mode = input_mode;
1629   ctx->dns_txt_callback = dns_txt_callback;
1630
1631   return ctx;
1632 }
1633
1634
1635 /* -------------------------------------------------------------------------- */
1636 DLLEXPORT pdkim_ctx *pdkim_init_sign(int input_mode,
1637                            char *domain,
1638                            char *selector,
1639                            char *rsa_privkey) {
1640   pdkim_ctx *ctx;
1641   pdkim_signature *sig;
1642
1643   if (!domain || !selector || !rsa_privkey) return NULL;
1644
1645   ctx = malloc(sizeof(pdkim_ctx));
1646   if (ctx == NULL) return NULL;
1647   memset(ctx,0,sizeof(pdkim_ctx));
1648
1649   ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN);
1650   if (ctx->linebuf == NULL) {
1651     free(ctx);
1652     return NULL;
1653   }
1654
1655   sig = malloc(sizeof(pdkim_signature));
1656   if (sig == NULL) {
1657     free(ctx->linebuf);
1658     free(ctx);
1659     return NULL;
1660   }
1661   memset(sig,0,sizeof(pdkim_signature));
1662   sig->bodylength = -1;
1663
1664   ctx->mode = PDKIM_MODE_SIGN;
1665   ctx->input_mode = input_mode;
1666   ctx->sig = sig;
1667
1668   ctx->sig->domain = strdup(domain);
1669   ctx->sig->selector = strdup(selector);
1670   ctx->sig->rsa_privkey = strdup(rsa_privkey);
1671
1672   if (!ctx->sig->domain || !ctx->sig->selector || !ctx->sig->rsa_privkey) {
1673     pdkim_free_ctx(ctx);
1674     return NULL;
1675   }
1676
1677   ctx->sig->sha1_body = malloc(sizeof(sha1_context));
1678   if (ctx->sig->sha1_body == NULL) {
1679     pdkim_free_ctx(ctx);
1680     return NULL;
1681   }
1682   sha1_starts(ctx->sig->sha1_body);
1683
1684   ctx->sig->sha2_body = malloc(sizeof(sha2_context));
1685   if (ctx->sig->sha2_body == NULL) {
1686     pdkim_free_ctx(ctx);
1687     return NULL;
1688   }
1689   sha2_starts(ctx->sig->sha2_body,0);
1690
1691   return ctx;
1692 }
1693
1694 #ifdef PDKIM_DEBUG
1695 /* -------------------------------------------------------------------------- */
1696 DLLEXPORT void pdkim_set_debug_stream(pdkim_ctx *ctx,
1697                             FILE *debug_stream) {
1698   ctx->debug_stream = debug_stream;
1699 }
1700 #endif
1701
1702 /* -------------------------------------------------------------------------- */
1703 DLLEXPORT int pdkim_set_optional(pdkim_ctx *ctx,
1704                        char *sign_headers,
1705                        char *identity,
1706                        int canon_headers,
1707                        int canon_body,
1708                        long bodylength,
1709                        int algo,
1710                        unsigned long created,
1711                        unsigned long expires) {
1712
1713   if (identity != NULL) {
1714     ctx->sig->identity = strdup(identity);
1715     if (ctx->sig->identity == NULL) return PDKIM_ERR_OOM;
1716   }
1717
1718   if (sign_headers != NULL) {
1719     ctx->sig->sign_headers = strdup(sign_headers);
1720     if (ctx->sig->sign_headers == NULL) return PDKIM_ERR_OOM;
1721   }
1722
1723   ctx->sig->canon_headers = canon_headers;
1724   ctx->sig->canon_body = canon_body;
1725   ctx->sig->bodylength = bodylength;
1726   ctx->sig->algo = algo;
1727   ctx->sig->created = created;
1728   ctx->sig->expires = expires;
1729
1730   return PDKIM_OK;
1731 }