Merge native DKIM support (from DEVEL_PDKIM)
[exim.git] / src / src / pdkim / pdkim.c
CommitLineData
80a47a2c
TK
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 1.2 2009/06/10 07:34:05 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/* -------------------------------------------------------------------------- */
54struct pdkim_stringlist {
55 char *value;
56 void *next;
57};
58
59#define PDKIM_STR_ALLOC_FRAG 256
60struct pdkim_str {
61 char *str;
62 unsigned int len;
63 unsigned int allocated;
64};
65
66/* -------------------------------------------------------------------------- */
67/* A bunch of list constants */
68char *pdkim_querymethods[] = {
69 "dns/txt",
70 NULL
71};
72char *pdkim_algos[] = {
73 "rsa-sha256",
74 "rsa-sha1",
75 NULL
76};
77char *pdkim_canons[] = {
78 "simple",
79 "relaxed",
80 NULL
81};
82char *pdkim_hashes[] = {
83 "sha256",
84 "sha1",
85 NULL
86};
87char *pdkim_keytypes[] = {
88 "rsa",
89 NULL
90};
91
92typedef struct pdkim_combined_canon_entry {
93 char *str;
94 int canon_headers;
95 int canon_body;
96} pdkim_combined_canon_entry;
97pdkim_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
111void 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}
135void 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 */
151pdkim_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
166
167/* -------------------------------------------------------------------------- */
168/* A small "growing string" implementation to escape malloc/realloc hell */
169pdkim_str *pdkim_strnew (char *cstr) {
170 unsigned int len = cstr?strlen(cstr):0;
171 pdkim_str *p = malloc(sizeof(pdkim_str));
172 if (p == NULL) return NULL;
173 memset(p,0,sizeof(pdkim_str));
174 p->str = malloc(len+1);
175 if (p->str == NULL) {
176 free(p);
177 return NULL;
178 }
179 p->allocated=(len+1);
180 p->len=len;
181 if (cstr) strcpy(p->str,cstr);
182 return p;
183};
184char *pdkim_strncat(pdkim_str *str, char *data, int len) {
185 if ((str->allocated - str->len) < (len+1)) {
186 /* Extend the buffer */
187 int num_frags = ((len+1)/PDKIM_STR_ALLOC_FRAG)+1;
188 char *n = realloc(str->str,
189 (str->allocated+(num_frags*PDKIM_STR_ALLOC_FRAG)));
190 if (n == NULL) return NULL;
191 str->str = n;
192 str->allocated += (num_frags*PDKIM_STR_ALLOC_FRAG);
193 }
194 strncpy(&(str->str[str->len]),data,len);
195 str->len+=len;
196 str->str[str->len] = '\0';
197 return str->str;
198};
199char *pdkim_strcat(pdkim_str *str, char *cstr) {
200 return pdkim_strncat(str, cstr, strlen(cstr));
201};
202char *pdkim_numcat(pdkim_str *str, unsigned long num) {
203 char minibuf[20];
204 snprintf(minibuf,20,"%lu",num);
205 return pdkim_strcat(str,minibuf);
206};
207char *pdkim_strtrim(pdkim_str *str) {
208 char *p = str->str;
209 char *q = str->str;
210 while ( (*p != '\0') && ((*p == '\t') || (*p == ' ')) ) p++;
211 while (*p != '\0') {*q = *p; q++; p++;};
212 *q = '\0';
213 while ( (q != str->str) && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) ) {
214 *q = '\0';
215 q--;
216 }
217 str->len = strlen(str->str);
218 return str->str;
219};
220char *pdkim_strclear(pdkim_str *str) {
221 str->str[0] = '\0';
222 str->len = 0;
223 return str->str;
224};
225void pdkim_strfree(pdkim_str *str) {
226 if (str == NULL) return;
227 if (str->str != NULL) free(str->str);
228 free(str);
229};
230
231
232
233/* -------------------------------------------------------------------------- */
234void pdkim_free_pubkey(pdkim_pubkey *pub) {
235 if (pub) {
236 if (pub->version != NULL) free(pub->version);
237 if (pub->granularity != NULL) free(pub->granularity);
238 if (pub->hashes != NULL) free(pub->hashes);
239 if (pub->keytype != NULL) free(pub->keytype);
240 if (pub->srvtype != NULL) free(pub->srvtype);
241 if (pub->notes != NULL) free(pub->notes);
242 if (pub->key != NULL) free(pub->key);
243 free(pub);
244 }
245}
246
247
248/* -------------------------------------------------------------------------- */
249void pdkim_free_sig(pdkim_signature *sig) {
250 if (sig) {
251 pdkim_signature *next = (pdkim_signature *)sig->next;
252
253 pdkim_stringlist *e = sig->headers;
254 while(e != NULL) {
255 pdkim_stringlist *c = e;
256 if (e->value != NULL) free(e->value);
257 e = e->next;
258 free(c);
259 }
260
261 if (sig->sigdata != NULL) free(sig->sigdata);
262 if (sig->bodyhash != NULL) free(sig->bodyhash);
263 if (sig->selector != NULL) free(sig->selector);
264 if (sig->domain != NULL) free(sig->domain);
265 if (sig->identity != NULL) free(sig->identity);
266 if (sig->headernames != NULL) free(sig->headernames);
267 if (sig->copiedheaders != NULL) free(sig->copiedheaders);
268 if (sig->rsa_privkey != NULL) free(sig->rsa_privkey);
269 if (sig->sign_headers != NULL) free(sig->sign_headers);
270 if (sig->signature_header != NULL) free(sig->signature_header);
271 if (sig->sha1_body != NULL) free(sig->sha1_body);
272 if (sig->sha2_body != NULL) free(sig->sha2_body);
273 if (sig->hnames_check != NULL) free(sig->hnames_check);
274
275 if (sig->pubkey != NULL) pdkim_free_pubkey(sig->pubkey);
276
277 free(sig);
278 if (next != NULL) pdkim_free_sig(next);
279 }
280};
281
282
283/* -------------------------------------------------------------------------- */
284DLLEXPORT void pdkim_free_ctx(pdkim_ctx *ctx) {
285 if (ctx) {
286 pdkim_free_sig(ctx->sig);
287 pdkim_strfree(ctx->cur_header);
288 free(ctx);
289 }
290};
291
292
293/* -------------------------------------------------------------------------- */
294/* Matches the name of the passed raw "header" against
295 the passed colon-separated "list", starting at entry
296 "start". Returns the position of the header name in
297 the list. */
298int header_name_match(char *header,
299 char *tick,
300 int do_tick) {
301 char *hname;
302 char *lcopy;
303 char *p;
304 char *q;
305 int rc = PDKIM_FAIL;
306
307 /* Get header name */
308 char *hcolon = strchr(header,':');
309 if (hcolon == NULL) return rc; /* This isn't a header */
310 hname = malloc((hcolon-header)+1);
311 if (hname == NULL) return PDKIM_ERR_OOM;
312 memset(hname,0,(hcolon-header)+1);
313 strncpy(hname,header,(hcolon-header));
314
315 /* Copy tick-off list locally, so we can punch zeroes into it */
316 lcopy = strdup(tick);
317 if (lcopy == NULL) {
318 free(hname);
319 return PDKIM_ERR_OOM;
320 }
321 p = lcopy;
322 q = strchr(p,':');
323 while (q != NULL) {
324 *q = '\0';
325
326 if (strcasecmp(p,hname) == 0) {
327 rc = PDKIM_OK;
328 /* Invalidate header name instance in tick-off list */
329 if (do_tick) tick[p-lcopy] = '_';
330 goto BAIL;
331 }
332
333 p = q+1;
334 q = strchr(p,':');
335 }
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 }
342
343 BAIL:
344 free(hname);
345 free(lcopy);
346 return rc;
347}
348
349
350/* -------------------------------------------------------------------------- */
351/* Performs "relaxed" canonicalization of a header. The returned pointer needs
352 to be free()d. */
353char *pdkim_relax_header (char *header, int crlf) {
354 int past_field_name = 0;
355 int seen_wsp = 0;
356 char *p = header;
357 char *q;
358 char *relaxed = malloc(strlen(header));
359 if (relaxed == NULL) return NULL;
360 q = relaxed;
361 while (*p != '\0') {
362 int c = *p;
363 /* Ignore CR & LF */
364 if ( (c == '\r') || (c == '\n') ) {
365 p++;
366 continue;
367 }
368 if ( (c == '\t') || (c == ' ') ) {
369 c = ' '; /* Turns WSP into SP */
370 if (seen_wsp) {
371 p++;
372 continue;
373 }
374 else seen_wsp = 1;
375 }
376 else {
377 if ( (!past_field_name) && (c == ':') ) {
378 if (seen_wsp) q--; /* This removes WSP before the colon */
379 seen_wsp = 1; /* This removes WSP after the colon */
380 past_field_name = 1;
381 }
382 else seen_wsp = 0;
383 }
384 /* Lowercase header name */
385 if (!past_field_name) c = tolower(c);
386 *q = c;
387 p++;
388 q++;
389 }
390 *q = '\0';
391 if (crlf) strcat(relaxed,"\r\n");
392 return relaxed;
393};
394
395
396/* -------------------------------------------------------------------------- */
397#define PDKIM_QP_ERROR_DECODE -1
398char *pdkim_decode_qp_char(char *qp_p, int *c) {
399 char *initial_pos = qp_p;
400
401 /* Advance one char */
402 qp_p++;
403
404 /* Check for two hex digits and decode them */
405 if (isxdigit(*qp_p) && isxdigit(qp_p[1])) {
406 /* Do hex conversion */
407 if (isdigit(*qp_p)) {*c = *qp_p - '0';}
408 else {*c = toupper(*qp_p) - 'A' + 10;};
409 *c <<= 4;
410 if (isdigit(qp_p[1])) {*c |= qp_p[1] - '0';}
411 else {*c |= toupper(qp_p[1]) - 'A' + 10;};
412 return qp_p + 2;
413 };
414
415 /* Illegal char here */
416 *c = PDKIM_QP_ERROR_DECODE;
417 return initial_pos;
418}
419
420
421/* -------------------------------------------------------------------------- */
422char *pdkim_decode_qp(char *str) {
423 int nchar = 0;
424 char *q;
425 char *p = str;
426 char *n = malloc(strlen(p)+1);
427 if (n == NULL) return NULL;
428 *n = '\0';
429 q = n;
430 while (*p != '\0') {
431 if (*p == '=') {
432 p = pdkim_decode_qp_char(p,&nchar);
433 if (nchar >= 0) {
434 *q = nchar;
435 q++;
436 continue;
437 }
438 }
439 else {
440 *q = *p;
441 q++;
442 }
443 p++;
444 }
445 *q = '\0';
446 return n;
447}
448
449
450/* -------------------------------------------------------------------------- */
451char *pdkim_decode_base64(char *str, int *num_decoded) {
452 int dlen = 0;
453 char *res;
454
455 base64_decode(NULL, &dlen, (unsigned char *)str, strlen(str));
456 res = malloc(dlen+1);
457 if (res == NULL) return NULL;
458 if (base64_decode((unsigned char *)res,&dlen,(unsigned char *)str,strlen(str)) != 0) {
459 free(res);
460 return NULL;
461 }
462 if (num_decoded != NULL) *num_decoded = dlen;
463 return res;
464}
465
466/* -------------------------------------------------------------------------- */
467char *pdkim_encode_base64(char *str, int num) {
468 int dlen = 0;
469 char *res;
470
471 base64_encode(NULL, &dlen, (unsigned char *)str, num);
472 res = malloc(dlen+1);
473 if (res == NULL) return NULL;
474 if (base64_encode((unsigned char *)res,&dlen,(unsigned char *)str,num) != 0) {
475 free(res);
476 return NULL;
477 }
478 return res;
479}
480
481
482/* -------------------------------------------------------------------------- */
483#define PDKIM_HDR_LIMBO 0
484#define PDKIM_HDR_TAG 1
485#define PDKIM_HDR_VALUE 2
486pdkim_signature *pdkim_parse_sig_header(pdkim_ctx *ctx, char *raw_hdr) {
487 pdkim_signature *sig ;
488 char *p,*q;
489 pdkim_str *cur_tag = NULL;
490 pdkim_str *cur_val = NULL;
491 int past_hname = 0;
492 int in_b_val = 0;
493 int where = PDKIM_HDR_LIMBO;
494 int i;
495
496 sig = malloc(sizeof(pdkim_signature));
497 if (sig == NULL) return NULL;
498 memset(sig,0,sizeof(pdkim_signature));
499 sig->bodylength = -1;
500
501 sig->rawsig_no_b_val = malloc(strlen(raw_hdr)+1);
502 if (sig->rawsig_no_b_val == NULL) {
503 free(sig);
504 return NULL;
505 }
506
507 p = raw_hdr;
508 q = sig->rawsig_no_b_val;
509
510 while (1) {
511
512 /* Ignore FWS */
513 if ( (*p == '\r') || (*p == '\n') )
514 goto NEXT_CHAR;
515
516 /* Fast-forward through header name */
517 if (!past_hname) {
518 if (*p == ':') past_hname = 1;
519 goto NEXT_CHAR;
520 }
521
522 if (where == PDKIM_HDR_LIMBO) {
523 /* In limbo, just wait for a tag-char to appear */
524 if (!((*p >= 'a') && (*p <= 'z')))
525 goto NEXT_CHAR;
526
527 where = PDKIM_HDR_TAG;
528 }
529
530 if (where == PDKIM_HDR_TAG) {
531 if (cur_tag == NULL)
532 cur_tag = pdkim_strnew(NULL);
533
534 if ((*p >= 'a') && (*p <= 'z'))
535 pdkim_strncat(cur_tag,p,1);
536
537 if (*p == '=') {
538 if (strcmp(cur_tag->str,"b") == 0) {
539 *q = '='; q++;
540 in_b_val = 1;
541 }
542 where = PDKIM_HDR_VALUE;
543 goto NEXT_CHAR;
544 }
545 }
546
547 if (where == PDKIM_HDR_VALUE) {
548 if (cur_val == NULL)
549 cur_val = pdkim_strnew(NULL);
550
551 if ( (*p == '\r') || (*p == '\n') || (*p == ' ') || (*p == '\t') )
552 goto NEXT_CHAR;
553
554 if ( (*p == ';') || (*p == '\0') ) {
555 if (cur_tag->len > 0) {
556 pdkim_strtrim(cur_val);
557 #ifdef PDKIM_DEBUG
558 if (ctx->debug_stream)
559 fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str);
560 #endif
561 switch (cur_tag->str[0]) {
562 case 'b':
563 switch (cur_tag->str[1]) {
564 case 'h':
565 sig->bodyhash = pdkim_decode_base64(cur_val->str,&(sig->bodyhash_len));
566 break;
567 default:
568 sig->sigdata = pdkim_decode_base64(cur_val->str,&(sig->sigdata_len));
569 break;
570 }
571 break;
572 case 'v':
573 if (strcmp(cur_val->str,PDKIM_SIGNATURE_VERSION) == 0) {
574 /* We only support version 1, and that is currently the
575 only version there is. */
576 sig->version = 1;
577 }
578 break;
579 case 'a':
580 i = 0;
581 while (pdkim_algos[i] != NULL) {
582 if (strcmp(cur_val->str,pdkim_algos[i]) == 0 ) {
583 sig->algo = i;
584 break;
585 }
586 i++;
587 }
588 break;
589 case 'c':
590 i = 0;
591 while (pdkim_combined_canons[i].str != NULL) {
592 if (strcmp(cur_val->str,pdkim_combined_canons[i].str) == 0 ) {
593 sig->canon_headers = pdkim_combined_canons[i].canon_headers;
594 sig->canon_body = pdkim_combined_canons[i].canon_body;
595 break;
596 }
597 i++;
598 }
599 break;
600 case 'q':
601 i = 0;
602 while (pdkim_querymethods[i] != NULL) {
603 if (strcmp(cur_val->str,pdkim_querymethods[i]) == 0 ) {
604 sig->querymethod = i;
605 break;
606 }
607 i++;
608 }
609 break;
610 case 's':
611 sig->selector = strdup(cur_val->str);
612 break;
613 case 'd':
614 sig->domain = strdup(cur_val->str);
615 break;
616 case 'i':
617 sig->identity = pdkim_decode_qp(cur_val->str);
618 break;
619 case 't':
620 sig->created = strtoul(cur_val->str,NULL,10);
621 break;
622 case 'x':
623 sig->expires = strtoul(cur_val->str,NULL,10);
624 break;
625 case 'l':
626 sig->bodylength = strtol(cur_val->str,NULL,10);
627 break;
628 case 'h':
629 sig->headernames = strdup(cur_val->str);
630 break;
631 case 'z':
632 sig->copiedheaders = pdkim_decode_qp(cur_val->str);
633 break;
634 default:
635 #ifdef PDKIM_DEBUG
636 if (ctx->debug_stream)
637 fprintf(ctx->debug_stream, "Unknown tag encountered\n");
638 #endif
639 break;
640 }
641 }
642 pdkim_strclear(cur_tag);
643 pdkim_strclear(cur_val);
644 in_b_val = 0;
645 where = PDKIM_HDR_LIMBO;
646 goto NEXT_CHAR;
647 }
648 else pdkim_strncat(cur_val,p,1);
649 }
650
651 NEXT_CHAR:
652 if (*p == '\0') break;
653
654 if (!in_b_val) {
655 *q = *p;
656 q++;
657 }
658 p++;
659 }
660
661 /* Make sure the most important bits are there. */
662 if (!(sig->domain && (*(sig->domain) != '\0') &&
663 sig->selector && (*(sig->selector) != '\0') &&
664 sig->headernames && (*(sig->headernames) != '\0') &&
665 sig->bodyhash &&
666 sig->sigdata &&
667 sig->version)) {
668 pdkim_free_sig(sig);
669 return NULL;
670 }
671
672 /* Copy header list to 'tick-off' header list */
673 sig->hnames_check = strdup(sig->headernames);
674
675 *q = '\0';
676 /* Chomp raw header. The final newline must not be added to the signature. */
677 q--;
678 while( (q > sig->rawsig_no_b_val) && ((*q == '\r') || (*q == '\n')) ) {
679 *q = '\0'; q--;
680 }
681
682 #ifdef PDKIM_DEBUG
683 if (ctx->debug_stream) {
684 fprintf(ctx->debug_stream,
685 "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
686 pdkim_quoteprint(ctx->debug_stream,
687 sig->rawsig_no_b_val,
688 strlen(sig->rawsig_no_b_val), 1);
689 fprintf(ctx->debug_stream,
690 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
691 }
692 #endif
693
694 sig->sha1_body = malloc(sizeof(sha1_context));
695 if (sig->sha1_body == NULL) {
696 pdkim_free_sig(sig);
697 return NULL;
698 }
699 sig->sha2_body = malloc(sizeof(sha2_context));
700 if (sig->sha2_body == NULL) {
701 pdkim_free_sig(sig);
702 return NULL;
703 }
704
705 sha1_starts(sig->sha1_body);
706 sha2_starts(sig->sha2_body,0);
707
708 return sig;
709}
710
711
712/* -------------------------------------------------------------------------- */
713pdkim_pubkey *pdkim_parse_pubkey_record(pdkim_ctx *ctx, char *raw_record) {
714 pdkim_pubkey *pub ;
715 char *p;
716 pdkim_str *cur_tag = NULL;
717 pdkim_str *cur_val = NULL;
718 int where = PDKIM_HDR_LIMBO;
719
720 pub = malloc(sizeof(pdkim_pubkey));
721 if (pub == NULL) return NULL;
722 memset(pub,0,sizeof(pdkim_pubkey));
723
724 p = raw_record;
725
726 while (1) {
727
728 /* Ignore FWS */
729 if ( (*p == '\r') || (*p == '\n') )
730 goto NEXT_CHAR;
731
732 if (where == PDKIM_HDR_LIMBO) {
733 /* In limbo, just wait for a tag-char to appear */
734 if (!((*p >= 'a') && (*p <= 'z')))
735 goto NEXT_CHAR;
736
737 where = PDKIM_HDR_TAG;
738 }
739
740 if (where == PDKIM_HDR_TAG) {
741 if (cur_tag == NULL)
742 cur_tag = pdkim_strnew(NULL);
743
744 if ((*p >= 'a') && (*p <= 'z'))
745 pdkim_strncat(cur_tag,p,1);
746
747 if (*p == '=') {
748 where = PDKIM_HDR_VALUE;
749 goto NEXT_CHAR;
750 }
751 }
752
753 if (where == PDKIM_HDR_VALUE) {
754 if (cur_val == NULL)
755 cur_val = pdkim_strnew(NULL);
756
757 if ( (*p == '\r') || (*p == '\n') )
758 goto NEXT_CHAR;
759
760 if ( (*p == ';') || (*p == '\0') ) {
761 if (cur_tag->len > 0) {
762 pdkim_strtrim(cur_val);
763 #ifdef PDKIM_DEBUG
764 if (ctx->debug_stream)
765 fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str);
766 #endif
767 switch (cur_tag->str[0]) {
768 case 'v':
769 /* This tag isn't evaluated because:
770 - We only support version DKIM1.
771 - Which is the default for this value (set below)
772 - Other versions are currently not specified. */
773 break;
774 case 'h':
775 pub->hashes = strdup(cur_val->str);
776 break;
777 case 'g':
778 pub->granularity = strdup(cur_val->str);
779 break;
780 case 'n':
781 pub->notes = pdkim_decode_qp(cur_val->str);
782 break;
783 case 'p':
784 pub->key = pdkim_decode_base64(cur_val->str,&(pub->key_len));
785 break;
786 case 'k':
787 pub->hashes = strdup(cur_val->str);
788 break;
789 case 's':
790 pub->srvtype = strdup(cur_val->str);
791 break;
792 case 't':
793 if (strchr(cur_val->str,'t') != NULL) pub->testing = 1;
794 if (strchr(cur_val->str,'s') != NULL) pub->no_subdomaining = 1;
795 break;
796 default:
797 #ifdef PDKIM_DEBUG
798 if (ctx->debug_stream)
799 fprintf(ctx->debug_stream, "Unknown tag encountered\n");
800 #endif
801 break;
802 }
803 }
804 pdkim_strclear(cur_tag);
805 pdkim_strclear(cur_val);
806 where = PDKIM_HDR_LIMBO;
807 goto NEXT_CHAR;
808 }
809 else pdkim_strncat(cur_val,p,1);
810 }
811
812 NEXT_CHAR:
813 if (*p == '\0') break;
814 p++;
815 }
816
817 /* Set fallback defaults */
818 if (pub->version == NULL) pub->version = strdup(PDKIM_PUB_RECORD_VERSION);
819 if (pub->granularity == NULL) pub->granularity = strdup("*");
820 if (pub->keytype == NULL) pub->keytype = strdup("rsa");
821 if (pub->srvtype == NULL) pub->srvtype = strdup("*");
822
823 /* p= is required */
824 if (pub->key == NULL) {
825 pdkim_free_pubkey(pub);
826 return NULL;
827 }
828
829 return pub;
830}
831
832
833/* -------------------------------------------------------------------------- */
834int pdkim_update_bodyhash(pdkim_ctx *ctx, char *data, int len) {
835 pdkim_signature *sig = ctx->sig;
836 /* Cache relaxed version of data */
837 char *relaxed_data = NULL;
838 int relaxed_len = 0;
839
840 /* Traverse all signatures, updating their hashes. */
841 while (sig != NULL) {
842 /* Defaults to simple canon (no further treatment necessary) */
843 char *canon_data = data;
844 int canon_len = len;
845
846 if (sig->canon_body == PDKIM_CANON_RELAXED) {
847 /* Relax the line if not done already */
848 if (relaxed_data == NULL) {
849 int seen_wsp = 0;
850 char *p = data;
851 int q = 0;
852 relaxed_data = malloc(len+1);
853 if (relaxed_data == NULL) return PDKIM_ERR_OOM;
854 while (*p != '\0') {
855 char c = *p;
856 if ( (c == '\t') || (c == ' ') ) {
857 c = ' '; /* Turns WSP into SP */
858 if (seen_wsp) {
859 p++;
860 continue;
861 }
862 else seen_wsp = 1;
863 }
864 else seen_wsp = 0;
865 relaxed_data[q++] = c;
866 p++;
867 }
868 relaxed_data[q] = '\0';
869 relaxed_len = q;
870 }
871 canon_data = relaxed_data;
872 canon_len = relaxed_len;
873 }
874
875 /* Make sure we don't exceed the to-be-signed body length */
876 if ((sig->bodylength >= 0) &&
877 ((sig->signed_body_bytes+(unsigned long)canon_len) > sig->bodylength))
878 canon_len = (sig->bodylength - sig->signed_body_bytes);
879
880 if (canon_len > 0) {
881 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
882 sha1_update(sig->sha1_body,(unsigned char *)canon_data,canon_len);
883 else
884 sha2_update(sig->sha2_body,(unsigned char *)canon_data,canon_len);
885 sig->signed_body_bytes += canon_len;
886#ifdef PDKIM_DEBUG
887 if (ctx->debug_stream!=NULL)
888 pdkim_quoteprint(ctx->debug_stream,canon_data,canon_len,0);
889#endif
890 }
891
892 sig = sig->next;
893 }
894
895 if (relaxed_data != NULL) free(relaxed_data);
896 return PDKIM_OK;
897};
898
899
900/* -------------------------------------------------------------------------- */
901int pdkim_finish_bodyhash(pdkim_ctx *ctx) {
902 pdkim_signature *sig = ctx->sig;
903
904 /* Traverse all signatures */
905 while (sig != NULL) {
906
907 /* Finish hashes */
908 unsigned char bh[32]; /* SHA-256 = 32 Bytes, SHA-1 = 20 Bytes */
909 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
910 sha1_finish(sig->sha1_body,bh);
911 else
912 sha2_finish(sig->sha2_body,bh);
913
914 #ifdef PDKIM_DEBUG
915 if (ctx->debug_stream) {
916 fprintf(ctx->debug_stream, "PDKIM [%s] Body bytes hashed: %lu\n",
917 sig->domain, sig->signed_body_bytes);
918 fprintf(ctx->debug_stream, "PDKIM [%s] bh computed: ", sig->domain);
919 pdkim_hexprint(ctx->debug_stream, (char *)bh,
920 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1);
921 }
922 #endif
923
924 /* SIGNING -------------------------------------------------------------- */
925 if (ctx->mode == PDKIM_MODE_SIGN) {
926 sig->bodyhash_len = (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32;
927 sig->bodyhash = malloc(sig->bodyhash_len);
928 if (sig->bodyhash == NULL) return PDKIM_ERR_OOM;
929 memcpy(sig->bodyhash,bh,sig->bodyhash_len);
930
931 /* If bodylength limit is set, and we have received less bytes
932 than the requested amount, effectively remove the limit tag. */
933 if (sig->signed_body_bytes < sig->bodylength) sig->bodylength = -1;
934 }
935 /* VERIFICATION --------------------------------------------------------- */
936 else {
937 /* Compare bodyhash */
938 if (memcmp(bh,sig->bodyhash,
939 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32) == 0) {
940 #ifdef PDKIM_DEBUG
941 if (ctx->debug_stream)
942 fprintf(ctx->debug_stream, "PDKIM [%s] Body hash verified OK\n",
943 sig->domain);
944 #endif
945 }
946 else {
947 #ifdef PDKIM_DEBUG
948 if (ctx->debug_stream) {
949 fprintf(ctx->debug_stream, "PDKIM [%s] Body hash did NOT verify\n",
950 sig->domain);
951 fprintf(ctx->debug_stream, "PDKIM [%s] bh signature: ", sig->domain);
952 pdkim_hexprint(ctx->debug_stream, sig->bodyhash,
953 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1);
954 }
955 #endif
956 sig->verify_status = PDKIM_VERIFY_FAIL;
957 sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY;
958 }
959 }
960
961 sig = sig->next;
962 }
963
964 return PDKIM_OK;
965};
966
967
968
969/* -------------------------------------------------------------------------- */
970/* Callback from pdkim_feed below for processing complete body lines */
971int pdkim_bodyline_complete(pdkim_ctx *ctx) {
972 char *p = ctx->linebuf;
973 int n = ctx->linebuf_offset;
974
975 /* Ignore extra data if we've seen the end-of-data marker */
976 if (ctx->seen_eod) goto BAIL;
977
978 /* We've always got one extra byte to stuff a zero ... */
979 ctx->linebuf[(ctx->linebuf_offset)] = '\0';
980
981 if (ctx->input_mode == PDKIM_INPUT_SMTP) {
982 /* Terminate on EOD marker */
983 if (memcmp(p,".\r\n",3) == 0) {
984 ctx->seen_eod = 1;
985 goto BAIL;
986 }
987 /* Unstuff dots */
988 if (memcmp(p,"..",2) == 0) {
989 p++;
990 n--;
991 }
992 }
993
994 /* Empty lines need to be buffered until we find a non-empty line */
995 if (memcmp(p,"\r\n",2) == 0) {
996 ctx->num_buffered_crlf++;
997 goto BAIL;
998 }
999
1000 /* At this point, we have a non-empty line, so release the buffered ones. */
1001 while (ctx->num_buffered_crlf) {
1002 pdkim_update_bodyhash(ctx,"\r\n",2);
1003 ctx->num_buffered_crlf--;
1004 }
1005
1006 pdkim_update_bodyhash(ctx,p,n);
1007
1008 BAIL:
1009 ctx->linebuf_offset = 0;
1010 return PDKIM_OK;
1011}
1012
1013
1014/* -------------------------------------------------------------------------- */
1015/* Callback from pdkim_feed below for processing complete headers */
1016#define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:"
1017int pdkim_header_complete(pdkim_ctx *ctx) {
1018 pdkim_signature *sig = ctx->sig;
1019
1020 /* Special case: The last header can have an extra \r appended */
1021 if ( (ctx->cur_header->len > 1) &&
1022 (ctx->cur_header->str[(ctx->cur_header->len)-1] == '\r') ) {
1023 ctx->cur_header->str[(ctx->cur_header->len)-1] = '\0';
1024 ctx->cur_header->len--;
1025 }
1026
1027 ctx->num_headers++;
1028 if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
1029
1030 /* Traverse all signatures */
1031 while (sig != NULL) {
1032 pdkim_stringlist *list;
1033
1034 /* SIGNING -------------------------------------------------------------- */
1035 if (ctx->mode == PDKIM_MODE_SIGN) {
1036 if (header_name_match(ctx->cur_header->str,
1037 sig->sign_headers?
1038 sig->sign_headers:
1039 PDKIM_DEFAULT_SIGN_HEADERS, 0) != PDKIM_OK) goto NEXT_SIG;
1040 }
1041 /* VERIFICATION --------------------------------------------------------- */
1042 else {
1043 /* Header is not included or all instances were already 'ticked off' */
1044 if (header_name_match(ctx->cur_header->str,
1045 sig->hnames_check, 1) != PDKIM_OK) goto NEXT_SIG;
1046 }
1047
1048 /* Add header to the signed headers list */
1049 list = pdkim_append_stringlist(sig->headers,
1050 ctx->cur_header->str);
1051 if (list == NULL) return PDKIM_ERR_OOM;
1052 sig->headers = list;
1053
1054 NEXT_SIG:
1055 sig = sig->next;
1056 }
1057
1058 /* DKIM-Signature: headers are added to the verification list */
1059 if ( (ctx->mode == PDKIM_MODE_VERIFY) &&
1060 (strncasecmp(ctx->cur_header->str,
1061 DKIM_SIGNATURE_HEADERNAME,
1062 strlen(DKIM_SIGNATURE_HEADERNAME)) == 0) ) {
1063 pdkim_signature *new_sig;
1064 /* Create and chain new signature block */
1065 #ifdef PDKIM_DEBUG
1066 if (ctx->debug_stream)
1067 fprintf(ctx->debug_stream,
1068 "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1069 #endif
1070 new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header->str);
1071 if (new_sig != NULL) {
1072 pdkim_signature *last_sig = ctx->sig;
1073 if (last_sig == NULL) {
1074 ctx->sig = new_sig;
1075 }
1076 else {
1077 while (last_sig->next != NULL) { last_sig = last_sig->next; };
1078 last_sig->next = new_sig;
1079 }
1080 }
1081 else {
1082 #ifdef PDKIM_DEBUG
1083 if (ctx->debug_stream) {
1084 fprintf(ctx->debug_stream,"Error while parsing signature header\n");
1085 fprintf(ctx->debug_stream,
1086 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1087 }
1088 #endif
1089 }
1090 }
1091
1092 BAIL:
1093 pdkim_strclear(ctx->cur_header); /* Re-use existing pdkim_str */
1094 return PDKIM_OK;
1095};
1096
1097
1098
1099/* -------------------------------------------------------------------------- */
1100#define HEADER_BUFFER_FRAG_SIZE 256
1101DLLEXPORT int pdkim_feed (pdkim_ctx *ctx,
1102 char *data,
1103 int len) {
1104 int p;
1105 for (p=0;p<len;p++) {
1106 char c = data[p];
1107 if (ctx->past_headers) {
1108 /* Processing body byte */
1109 ctx->linebuf[(ctx->linebuf_offset)++] = c;
1110 if (c == '\n') {
1111 int rc = pdkim_bodyline_complete(ctx); /* End of line */
1112 if (rc != PDKIM_OK) return rc;
1113 }
1114 if (ctx->linebuf_offset == (PDKIM_MAX_BODY_LINE_LEN-1))
1115 return PDKIM_ERR_LONG_LINE;
1116 }
1117 else {
1118 /* Processing header byte */
1119 if (c != '\r') {
1120 if (c == '\n') {
1121 if (ctx->seen_lf) {
1122 int rc = pdkim_header_complete(ctx); /* Seen last header line */
1123 if (rc != PDKIM_OK) return rc;
1124 ctx->past_headers = 1;
1125 ctx->seen_lf = 0;
1126#ifdef PDKIM_DEBUG
1127 if (ctx->debug_stream)
1128 fprintf(ctx->debug_stream,
1129 "PDKIM >> Hashed body data, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1130#endif
1131 continue;
1132 }
1133 else ctx->seen_lf = 1;
1134 }
1135 else if (ctx->seen_lf) {
1136 if (! ((c == '\t') || (c == ' '))) {
1137 int rc = pdkim_header_complete(ctx); /* End of header */
1138 if (rc != PDKIM_OK) return rc;
1139 }
1140 ctx->seen_lf = 0;
1141 }
1142 }
1143 if (ctx->cur_header == NULL) {
1144 ctx->cur_header = pdkim_strnew(NULL);
1145 if (ctx->cur_header == NULL) return PDKIM_ERR_OOM;
1146 }
1147 if (ctx->cur_header->len < PDKIM_MAX_HEADER_LEN)
1148 if (pdkim_strncat(ctx->cur_header,&data[p],1) == NULL)
1149 return PDKIM_ERR_OOM;
1150 }
1151 }
1152 return PDKIM_OK;
1153};
1154
1155
1156/* -------------------------------------------------------------------------- */
1157char *pdkim_create_header(pdkim_signature *sig, int final) {
1158 char *rc = NULL;
1159 char *base64_bh = NULL;
1160 char *base64_b = NULL;
1161 pdkim_str *hdr = pdkim_strnew("DKIM-Signature: v="PDKIM_SIGNATURE_VERSION);
1162 if (hdr == NULL) return NULL;
1163
1164 base64_bh = pdkim_encode_base64(sig->bodyhash, sig->bodyhash_len);
1165 if (base64_bh == NULL) goto BAIL;
1166
1167 /* Required and static bits */
1168 if (
1169 pdkim_strcat(hdr,"; a=") &&
1170 pdkim_strcat(hdr,pdkim_algos[sig->algo]) &&
1171 pdkim_strcat(hdr,"; q=") &&
1172 pdkim_strcat(hdr,pdkim_querymethods[sig->querymethod]) &&
1173 pdkim_strcat(hdr,"; c=") &&
1174 pdkim_strcat(hdr,pdkim_canons[sig->canon_headers]) &&
1175 pdkim_strcat(hdr,"/") &&
1176 pdkim_strcat(hdr,pdkim_canons[sig->canon_body]) &&
1177 pdkim_strcat(hdr,"; d=") &&
1178 pdkim_strcat(hdr,sig->domain) &&
1179 pdkim_strcat(hdr,"; s=") &&
1180 pdkim_strcat(hdr,sig->selector) &&
1181 pdkim_strcat(hdr,";\r\n\th=") &&
1182 pdkim_strcat(hdr,sig->headernames) &&
1183 pdkim_strcat(hdr,"; bh=") &&
1184 pdkim_strcat(hdr,base64_bh) &&
1185 pdkim_strcat(hdr,";\r\n\t")
1186 ) {
1187 /* Optional bits */
1188 if (sig->identity != NULL) {
1189 if (!( pdkim_strcat(hdr,"i=") &&
1190 pdkim_strcat(hdr,sig->identity) &&
1191 pdkim_strcat(hdr,";") ) ) {
1192 goto BAIL;
1193 }
1194 }
1195 if (sig->created > 0) {
1196 if (!( pdkim_strcat(hdr,"t=") &&
1197 pdkim_numcat(hdr,sig->created) &&
1198 pdkim_strcat(hdr,";") ) ) {
1199 goto BAIL;
1200 }
1201 }
1202 if (sig->expires > 0) {
1203 if (!( pdkim_strcat(hdr,"x=") &&
1204 pdkim_numcat(hdr,sig->expires) &&
1205 pdkim_strcat(hdr,";") ) ) {
1206 goto BAIL;
1207 }
1208 }
1209 if (sig->bodylength >= 0) {
1210 if (!( pdkim_strcat(hdr,"l=") &&
1211 pdkim_numcat(hdr,sig->bodylength) &&
1212 pdkim_strcat(hdr,";") ) ) {
1213 goto BAIL;
1214 }
1215 }
1216 /* Extra linebreak */
1217 if (hdr->str[(hdr->len)-1] == ';') {
1218 if (!pdkim_strcat(hdr," \r\n\t")) goto BAIL;
1219 }
1220 /* Preliminary or final version? */
1221 if (final) {
1222 base64_b = pdkim_encode_base64(sig->sigdata, sig->sigdata_len);
1223 if (base64_b == NULL) goto BAIL;
1224 if (
1225 pdkim_strcat(hdr,"b=") &&
1226 pdkim_strcat(hdr,base64_b) &&
1227 pdkim_strcat(hdr,";")
1228 ) goto DONE;
1229 }
1230 else {
1231 if (pdkim_strcat(hdr,"b=;")) goto DONE;
1232 }
1233
1234 goto BAIL;
1235 }
1236
1237 DONE:
1238 rc = strdup(hdr->str);
1239
1240 BAIL:
1241 pdkim_strfree(hdr);
1242 if (base64_bh != NULL) free(base64_bh);
1243 if (base64_b != NULL) free(base64_b);
1244 return rc;
1245}
1246
1247
1248/* -------------------------------------------------------------------------- */
1249DLLEXPORT int pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures) {
1250 pdkim_signature *sig = ctx->sig;
1251 pdkim_str *headernames = NULL; /* Collected signed header names */
1252
1253 /* Check if we must still flush a (partial) header. If that is the
1254 case, the message has no body, and we must compute a body hash
1255 out of '<CR><LF>' */
1256 if (ctx->cur_header->len) {
1257 int rc = pdkim_header_complete(ctx);
1258 if (rc != PDKIM_OK) return rc;
1259 pdkim_update_bodyhash(ctx,"\r\n",2);
1260 }
1261 else {
1262 /* For non-smtp input, check if there's an unfinished line in the
1263 body line buffer. If that is the case, we must add a CRLF to the
1264 hash to properly terminate the message. */
1265 if ((ctx->input_mode == PDKIM_INPUT_NORMAL) && ctx->linebuf_offset) {
1266 pdkim_update_bodyhash(ctx, ctx->linebuf, ctx->linebuf_offset);
1267 pdkim_update_bodyhash(ctx,"\r\n",2);
1268 }
1269 #ifdef PDKIM_DEBUG
1270 if (ctx->debug_stream)
1271 fprintf(ctx->debug_stream,
1272 "\nPDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1273 #endif
1274 }
1275
1276 /* Build (and/or evaluate) body hash */
1277 if (pdkim_finish_bodyhash(ctx) != PDKIM_OK) return PDKIM_ERR_OOM;
1278
1279 /* SIGNING -------------------------------------------------------------- */
1280 if (ctx->mode == PDKIM_MODE_SIGN) {
1281 headernames = pdkim_strnew(NULL);
1282 if (headernames == NULL) return PDKIM_ERR_OOM;
1283 }
1284 /* ---------------------------------------------------------------------- */
1285
1286 while (sig != NULL) {
1287 sha1_context sha1_headers;
1288 sha2_context sha2_headers;
1289 char *sig_hdr;
1290 char headerhash[32];
1291
1292 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1293 sha1_starts(&sha1_headers);
1294 else
1295 sha2_starts(&sha2_headers,0);
1296
1297 #ifdef PDKIM_DEBUG
1298 if (ctx->debug_stream)
1299 fprintf(ctx->debug_stream,
1300 "PDKIM >> Hashed header data, canonicalized, in sequence >>>>>>>>>>>>>>\n");
1301 #endif
1302
1303 /* SIGNING ---------------------------------------------------------------- */
1304 /* When signing, walk through our header list and add them to the hash. As we
1305 go, construct a list of the header's names to use for the h= parameter. */
1306 if (ctx->mode == PDKIM_MODE_SIGN) {
1307 pdkim_stringlist *p = sig->headers;
1308 while (p != NULL) {
1309 char *rh = NULL;
1310 /* Collect header names (Note: colon presence is guaranteed here) */
1311 char *q = strchr(p->value,':');
1312 if (pdkim_strncat(headernames, p->value,
1313 (q-(p->value))+((p->next==NULL)?0:1)) == NULL)
1314 return PDKIM_ERR_OOM;
1315
1316 if (sig->canon_headers == PDKIM_CANON_RELAXED)
1317 rh = pdkim_relax_header(p->value,1); /* cook header for relaxed canon */
1318 else
1319 rh = strdup(p->value); /* just copy it for simple canon */
1320
1321 if (rh == NULL) return PDKIM_ERR_OOM;
1322
1323 /* Feed header to the hash algorithm */
1324 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1325 sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh));
1326 else
1327 sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh));
1328 #ifdef PDKIM_DEBUG
1329 if (ctx->debug_stream)
1330 pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1);
1331 #endif
1332 free(rh);
1333 p = p->next;
1334 }
1335 }
1336 /* VERIFICATION ----------------------------------------------------------- */
1337 /* When verifying, walk through the header name list in the h= parameter and
1338 add the headers to the hash in that order. */
1339 else {
1340 char *b = strdup(sig->headernames);
1341 char *p = b;
1342 char *q = NULL;
1343 if (b == NULL) return PDKIM_ERR_OOM;
1344
1345 while(1) {
1346 pdkim_stringlist *hdrs = sig->headers;
1347 q = strchr(p,':');
1348 if (q != NULL) *q = '\0';
1349 while (hdrs != NULL) {
1350 if (strncasecmp(hdrs->value,p,strlen(p)) == 0) {
1351 char *rh = NULL;
1352 if (sig->canon_headers == PDKIM_CANON_RELAXED)
1353 rh = pdkim_relax_header(hdrs->value,1); /* cook header for relaxed canon */
1354 else
1355 rh = strdup(hdrs->value); /* just copy it for simple canon */
1356 if (rh == NULL) return PDKIM_ERR_OOM;
1357 /* Feed header to the hash algorithm */
1358 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1359 sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh));
1360 else
1361 sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh));
1362 #ifdef PDKIM_DEBUG
1363 if (ctx->debug_stream)
1364 pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1);
1365 #endif
1366 free(rh);
1367 }
1368 hdrs = hdrs->next;
1369 }
1370 if (q == NULL) break;
1371 p = q+1;
1372 }
1373 free(b);
1374 }
1375
1376 #ifdef PDKIM_DEBUG
1377 if (ctx->debug_stream)
1378 fprintf(ctx->debug_stream,
1379 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1380 #endif
1381
1382 /* SIGNING ---------------------------------------------------------------- */
1383 if (ctx->mode == PDKIM_MODE_SIGN) {
1384 /* Copy headernames to signature struct */
1385 sig->headernames = strdup(headernames->str);
1386 pdkim_strfree(headernames);
1387
1388 /* Create signature header with b= omitted */
1389 sig_hdr = pdkim_create_header(ctx->sig,0);
1390 }
1391 /* VERIFICATION ----------------------------------------------------------- */
1392 else {
1393 sig_hdr = strdup(sig->rawsig_no_b_val);
1394 }
1395 /* ------------------------------------------------------------------------ */
1396
1397 if (sig_hdr == NULL) return PDKIM_ERR_OOM;
1398
1399 /* Relax header if necessary */
1400 if (sig->canon_headers == PDKIM_CANON_RELAXED) {
1401 char *relaxed_hdr = pdkim_relax_header(sig_hdr,0);
1402 free(sig_hdr);
1403 if (relaxed_hdr == NULL) return PDKIM_ERR_OOM;
1404 sig_hdr = relaxed_hdr;
1405 }
1406
1407 #ifdef PDKIM_DEBUG
1408 if (ctx->debug_stream) {
1409 fprintf(ctx->debug_stream,
1410 "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
1411 pdkim_quoteprint(ctx->debug_stream, sig_hdr, strlen(sig_hdr), 1);
1412 fprintf(ctx->debug_stream,
1413 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1414 }
1415 #endif
1416
1417 /* Finalize header hash */
1418 if (sig->algo == PDKIM_ALGO_RSA_SHA1) {
1419 sha1_update(&(sha1_headers),(unsigned char *)sig_hdr,strlen(sig_hdr));
1420 sha1_finish(&(sha1_headers),(unsigned char *)headerhash);
1421 #ifdef PDKIM_DEBUG
1422 if (ctx->debug_stream) {
1423 fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain);
1424 pdkim_hexprint(ctx->debug_stream, headerhash, 20, 1);
1425 }
1426 #endif
1427 }
1428 else {
1429 sha2_update(&(sha2_headers),(unsigned char *)sig_hdr,strlen(sig_hdr));
1430 sha2_finish(&(sha2_headers),(unsigned char *)headerhash);
1431 #ifdef PDKIM_DEBUG
1432 if (ctx->debug_stream) {
1433 fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain);
1434 pdkim_hexprint(ctx->debug_stream, headerhash, 32, 1);
1435 }
1436 #endif
1437 }
1438
1439 free(sig_hdr);
1440
1441 /* SIGNING ---------------------------------------------------------------- */
1442 if (ctx->mode == PDKIM_MODE_SIGN) {
1443 rsa_context rsa;
1444
1445 rsa_init(&rsa,RSA_PKCS_V15,0,NULL,NULL);
1446
1447 /* Perform private key operation */
1448 if (rsa_parse_key(&rsa, (unsigned char *)sig->rsa_privkey,
1449 strlen(sig->rsa_privkey), NULL, 0) != 0) {
1450 return PDKIM_ERR_RSA_PRIVKEY;
1451 }
1452
1453 sig->sigdata_len = mpi_size(&(rsa.N));
1454 sig->sigdata = malloc(sig->sigdata_len);
1455 if (sig->sigdata == NULL) return PDKIM_ERR_OOM;
1456
1457 if (rsa_pkcs1_sign( &rsa, RSA_PRIVATE,
1458 ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1459 RSA_SHA1:RSA_SHA256),
1460 0,
1461 (unsigned char *)headerhash,
1462 (unsigned char *)sig->sigdata ) != 0) {
1463 return PDKIM_ERR_RSA_SIGNING;
1464 }
1465
1466 rsa_free(&rsa);
1467
1468 #ifdef PDKIM_DEBUG
1469 if (ctx->debug_stream) {
1470 fprintf(ctx->debug_stream, "PDKIM [%s] b computed: ",
1471 sig->domain);
1472 pdkim_hexprint(ctx->debug_stream, sig->sigdata, sig->sigdata_len, 1);
1473 }
1474 #endif
1475
1476 sig->signature_header = pdkim_create_header(ctx->sig,1);
1477 if (sig->signature_header == NULL) return PDKIM_ERR_OOM;
1478 }
1479 /* VERIFICATION ----------------------------------------------------------- */
1480 else {
1481 rsa_context rsa;
1482 char *dns_txt_name, *dns_txt_reply;
1483
1484 rsa_init(&rsa,RSA_PKCS_V15,0,NULL,NULL);
1485
1486 dns_txt_name = malloc(PDKIM_DNS_TXT_MAX_NAMELEN);
1487 if (dns_txt_name == NULL) return PDKIM_ERR_OOM;
1488 dns_txt_reply = malloc(PDKIM_DNS_TXT_MAX_RECLEN);
1489 if (dns_txt_reply == NULL) {
1490 free(dns_txt_name);
1491 return PDKIM_ERR_OOM;
1492 }
1493 memset(dns_txt_reply,0,PDKIM_DNS_TXT_MAX_RECLEN);
1494 memset(dns_txt_name ,0,PDKIM_DNS_TXT_MAX_NAMELEN);
1495
1496 if (snprintf(dns_txt_name,PDKIM_DNS_TXT_MAX_NAMELEN,
1497 "%s._domainkey.%s.",
1498 sig->selector,sig->domain) >= PDKIM_DNS_TXT_MAX_NAMELEN) {
1499 sig->verify_status = PDKIM_VERIFY_INVALID;
1500 sig->verify_ext_status = PDKIM_VERIFY_INVALID_BUFFER_SIZE;
1501 goto NEXT_VERIFY;
1502 };
1503
1504 if ((ctx->dns_txt_callback(dns_txt_name, dns_txt_reply) != PDKIM_OK) ||
1505 (dns_txt_reply[0] == '\0')) {
1506 sig->verify_status = PDKIM_VERIFY_INVALID;
1507 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
1508 goto NEXT_VERIFY;
1509 }
1510
1511 #ifdef PDKIM_DEBUG
1512 if (ctx->debug_stream) {
1513 fprintf(ctx->debug_stream,
1514 "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1515 fprintf(ctx->debug_stream,"Raw record: ");
1516 pdkim_quoteprint(ctx->debug_stream, dns_txt_reply, strlen(dns_txt_reply), 1);
1517 }
1518 #endif
1519
1520 sig->pubkey = pdkim_parse_pubkey_record(ctx,dns_txt_reply);
1521 if (sig->pubkey == NULL) {
1522 sig->verify_status = PDKIM_VERIFY_INVALID;
1523 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1524 #ifdef PDKIM_DEBUG
1525 if (ctx->debug_stream) {
1526 fprintf(ctx->debug_stream,"Error while parsing public key record\n");
1527 fprintf(ctx->debug_stream,
1528 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1529 }
1530 #endif
1531 goto NEXT_VERIFY;
1532 }
1533
1534 #ifdef PDKIM_DEBUG
1535 if (ctx->debug_stream) {
1536 fprintf(ctx->debug_stream,
1537 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1538 }
1539 #endif
1540
1541 if (rsa_parse_public_key(&rsa,
1542 (unsigned char *)sig->pubkey->key,
1543 sig->pubkey->key_len) != 0) {
1544 sig->verify_status = PDKIM_VERIFY_INVALID;
1545 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1546 goto NEXT_VERIFY;
1547 }
1548
1549 /* Check the signature */
1550 if (rsa_pkcs1_verify(&rsa,
1551 RSA_PUBLIC,
1552 ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1553 RSA_SHA1:RSA_SHA256),
1554 0,
1555 (unsigned char *)headerhash,
1556 (unsigned char *)sig->sigdata) != 0) {
1557 sig->verify_status = PDKIM_VERIFY_FAIL;
1558 sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE;
1559 #ifdef PDKIM_DEBUG
1560 if (ctx->debug_stream) {
1561 fprintf(ctx->debug_stream, "PDKIM [%s] signature did NOT verify OK\n",
1562 sig->domain);
1563 }
1564 #endif
1565 goto NEXT_VERIFY;
1566 }
1567
1568 /* We have a winner! */
1569 sig->verify_status = PDKIM_VERIFY_PASS;
1570
1571 #ifdef PDKIM_DEBUG
1572 if (ctx->debug_stream) {
1573 fprintf(ctx->debug_stream, "PDKIM [%s] signature verified OK\n",
1574 sig->domain);
1575 }
1576 #endif
1577
1578 NEXT_VERIFY:
1579 rsa_free(&rsa);
1580 free(dns_txt_name);
1581 free(dns_txt_reply);
1582 }
1583
1584 sig = sig->next;
1585 }
1586
1587 /* If requested, set return pointer to signature(s) */
1588 if (return_signatures != NULL) {
1589 *return_signatures = ctx->sig;
1590 }
1591
1592 return PDKIM_OK;
1593}
1594
1595
1596/* -------------------------------------------------------------------------- */
1597DLLEXPORT pdkim_ctx *pdkim_init_verify(int input_mode,
1598 int(*dns_txt_callback)(char *, char *)
1599 ) {
1600 pdkim_ctx *ctx = malloc(sizeof(pdkim_ctx));
1601 if (ctx == NULL) return NULL;
1602 memset(ctx,0,sizeof(pdkim_ctx));
1603
1604 ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN);
1605 if (ctx->linebuf == NULL) {
1606 free(ctx);
1607 return NULL;
1608 }
1609
1610 ctx->mode = PDKIM_MODE_VERIFY;
1611 ctx->input_mode = input_mode;
1612 ctx->dns_txt_callback = dns_txt_callback;
1613
1614 return ctx;
1615}
1616
1617
1618/* -------------------------------------------------------------------------- */
1619DLLEXPORT pdkim_ctx *pdkim_init_sign(int input_mode,
1620 char *domain,
1621 char *selector,
1622 char *rsa_privkey) {
1623 pdkim_ctx *ctx;
1624 pdkim_signature *sig;
1625
1626 if (!domain || !selector || !rsa_privkey) return NULL;
1627
1628 ctx = malloc(sizeof(pdkim_ctx));
1629 if (ctx == NULL) return NULL;
1630 memset(ctx,0,sizeof(pdkim_ctx));
1631
1632 ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN);
1633 if (ctx->linebuf == NULL) {
1634 free(ctx);
1635 return NULL;
1636 }
1637
1638 sig = malloc(sizeof(pdkim_signature));
1639 if (sig == NULL) {
1640 free(ctx->linebuf);
1641 free(ctx);
1642 return NULL;
1643 }
1644 memset(sig,0,sizeof(pdkim_signature));
1645 sig->bodylength = -1;
1646
1647 ctx->mode = PDKIM_MODE_SIGN;
1648 ctx->input_mode = input_mode;
1649 ctx->sig = sig;
1650
1651 ctx->sig->domain = strdup(domain);
1652 ctx->sig->selector = strdup(selector);
1653 ctx->sig->rsa_privkey = strdup(rsa_privkey);
1654
1655 if (!ctx->sig->domain || !ctx->sig->selector || !ctx->sig->rsa_privkey) {
1656 pdkim_free_ctx(ctx);
1657 return NULL;
1658 }
1659
1660 ctx->sig->sha1_body = malloc(sizeof(sha1_context));
1661 if (ctx->sig->sha1_body == NULL) {
1662 pdkim_free_ctx(ctx);
1663 return NULL;
1664 }
1665 sha1_starts(ctx->sig->sha1_body);
1666
1667 ctx->sig->sha2_body = malloc(sizeof(sha2_context));
1668 if (ctx->sig->sha2_body == NULL) {
1669 pdkim_free_ctx(ctx);
1670 return NULL;
1671 }
1672 sha2_starts(ctx->sig->sha2_body,0);
1673
1674 return ctx;
1675};
1676
1677#ifdef PDKIM_DEBUG
1678/* -------------------------------------------------------------------------- */
1679DLLEXPORT void pdkim_set_debug_stream(pdkim_ctx *ctx,
1680 FILE *debug_stream) {
1681 ctx->debug_stream = debug_stream;
1682};
1683#endif
1684
1685/* -------------------------------------------------------------------------- */
1686DLLEXPORT int pdkim_set_optional(pdkim_ctx *ctx,
1687 char *sign_headers,
1688 char *identity,
1689 int canon_headers,
1690 int canon_body,
1691 long bodylength,
1692 int algo,
1693 unsigned long created,
1694 unsigned long expires) {
1695
1696 if (identity != NULL) {
1697 ctx->sig->identity = strdup(identity);
1698 if (ctx->sig->identity == NULL) return PDKIM_ERR_OOM;
1699 }
1700
1701 if (sign_headers != NULL) {
1702 ctx->sig->sign_headers = strdup(sign_headers);
1703 if (ctx->sig->sign_headers == NULL) return PDKIM_ERR_OOM;
1704 }
1705
1706 ctx->sig->canon_headers = canon_headers;
1707 ctx->sig->canon_body = canon_body;
1708 ctx->sig->bodylength = bodylength;
1709 ctx->sig->algo = algo;
1710 ctx->sig->created = created;
1711 ctx->sig->expires = expires;
1712
1713 return PDKIM_OK;
1714};