0147f5f05ce0923cb487a8dbfd6c809436bfa72b
[exim.git] / 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 1.14 2010/05/29 19:14:06 nm4 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 char *pdkim_verify_status_str(int status) {
109 switch(status) {
110 case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE";
111 case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID";
112 case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL";
113 case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS";
114 default: return "PDKIM_VERIFY_UNKNOWN";
115 }
116 }
117 char *pdkim_verify_ext_status_str(int ext_status) {
118 switch(ext_status) {
119 case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY";
120 case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE";
121 case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE";
122 case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE";
123 case PDKIM_VERIFY_INVALID_PUBKEY_PARSING: return "PDKIM_VERIFY_INVALID_PUBKEY_PARSING";
124 default: return "PDKIM_VERIFY_UNKNOWN";
125 }
126 }
127
128
129 /* -------------------------------------------------------------------------- */
130 /* Print debugging functions */
131 #ifdef PDKIM_DEBUG
132 void pdkim_quoteprint(FILE *stream, char *data, int len, int lf) {
133 int i;
134 unsigned char *p = (unsigned char *)data;
135
136 for (i=0;i<len;i++) {
137 int c = p[i];
138 switch (c) {
139 case ' ' : fprintf(stream,"{SP}"); break;
140 case '\t': fprintf(stream,"{TB}"); break;
141 case '\r': fprintf(stream,"{CR}"); break;
142 case '\n': fprintf(stream,"{LF}"); break;
143 case '{' : fprintf(stream,"{BO}"); break;
144 case '}' : fprintf(stream,"{BC}"); break;
145 default:
146 if ( (c < 32) || (c > 127) )
147 fprintf(stream,"{%02x}",c);
148 else
149 fputc(c,stream);
150 break;
151 }
152 }
153 if (lf)
154 fputc('\n',stream);
155 }
156 void pdkim_hexprint(FILE *stream, char *data, int len, int lf) {
157 int i;
158 unsigned char *p = (unsigned char *)data;
159
160 for (i=0;i<len;i++) {
161 int c = p[i];
162 fprintf(stream,"%02x",c);
163 }
164 if (lf)
165 fputc('\n',stream);
166 }
167 #endif
168
169
170 /* -------------------------------------------------------------------------- */
171 /* Simple string list implementation for convinience */
172 pdkim_stringlist *pdkim_append_stringlist(pdkim_stringlist *base, char *str) {
173 pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
174 if (new_entry == NULL) return NULL;
175 memset(new_entry,0,sizeof(pdkim_stringlist));
176 new_entry->value = strdup(str);
177 if (new_entry->value == NULL) return NULL;
178 if (base != NULL) {
179 pdkim_stringlist *last = base;
180 while (last->next != NULL) { last = last->next; }
181 last->next = new_entry;
182 return base;
183 }
184 else return new_entry;
185 }
186 pdkim_stringlist *pdkim_prepend_stringlist(pdkim_stringlist *base, char *str) {
187 pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
188 if (new_entry == NULL) return NULL;
189 memset(new_entry,0,sizeof(pdkim_stringlist));
190 new_entry->value = strdup(str);
191 if (new_entry->value == NULL) return NULL;
192 if (base != NULL) {
193 new_entry->next = base;
194 }
195 return new_entry;
196 }
197
198
199 /* -------------------------------------------------------------------------- */
200 /* A small "growing string" implementation to escape malloc/realloc hell */
201 pdkim_str *pdkim_strnew (char *cstr) {
202 unsigned int len = cstr?strlen(cstr):0;
203 pdkim_str *p = malloc(sizeof(pdkim_str));
204 if (p == NULL) return NULL;
205 memset(p,0,sizeof(pdkim_str));
206 p->str = malloc(len+1);
207 if (p->str == NULL) {
208 free(p);
209 return NULL;
210 }
211 p->allocated=(len+1);
212 p->len=len;
213 if (cstr) strcpy(p->str,cstr);
214 else p->str[p->len] = '\0';
215 return p;
216 }
217 char *pdkim_strncat(pdkim_str *str, char *data, int len) {
218 if ((str->allocated - str->len) < (len+1)) {
219 /* Extend the buffer */
220 int num_frags = ((len+1)/PDKIM_STR_ALLOC_FRAG)+1;
221 char *n = realloc(str->str,
222 (str->allocated+(num_frags*PDKIM_STR_ALLOC_FRAG)));
223 if (n == NULL) return NULL;
224 str->str = n;
225 str->allocated += (num_frags*PDKIM_STR_ALLOC_FRAG);
226 }
227 strncpy(&(str->str[str->len]),data,len);
228 str->len+=len;
229 str->str[str->len] = '\0';
230 return str->str;
231 }
232 char *pdkim_strcat(pdkim_str *str, char *cstr) {
233 return pdkim_strncat(str, cstr, strlen(cstr));
234 }
235 char *pdkim_numcat(pdkim_str *str, unsigned long num) {
236 char minibuf[20];
237 snprintf(minibuf,20,"%lu",num);
238 return pdkim_strcat(str,minibuf);
239 }
240 char *pdkim_strtrim(pdkim_str *str) {
241 char *p = str->str;
242 char *q = str->str;
243 while ( (*p != '\0') && ((*p == '\t') || (*p == ' ')) ) p++;
244 while (*p != '\0') {*q = *p; q++; p++;}
245 *q = '\0';
246 while ( (q != str->str) && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) ) {
247 *q = '\0';
248 q--;
249 }
250 str->len = strlen(str->str);
251 return str->str;
252 }
253 char *pdkim_strclear(pdkim_str *str) {
254 str->str[0] = '\0';
255 str->len = 0;
256 return str->str;
257 }
258 void pdkim_strfree(pdkim_str *str) {
259 if (str == NULL) return;
260 if (str->str != NULL) free(str->str);
261 free(str);
262 }
263
264
265
266 /* -------------------------------------------------------------------------- */
267 void pdkim_free_pubkey(pdkim_pubkey *pub) {
268 if (pub) {
269 if (pub->version != NULL) free(pub->version);
270 if (pub->granularity != NULL) free(pub->granularity);
271 if (pub->hashes != NULL) free(pub->hashes);
272 if (pub->keytype != NULL) free(pub->keytype);
273 if (pub->srvtype != NULL) free(pub->srvtype);
274 if (pub->notes != NULL) free(pub->notes);
275 if (pub->key != NULL) free(pub->key);
276 free(pub);
277 }
278 }
279
280
281 /* -------------------------------------------------------------------------- */
282 void pdkim_free_sig(pdkim_signature *sig) {
283 if (sig) {
284 pdkim_signature *next = (pdkim_signature *)sig->next;
285
286 pdkim_stringlist *e = sig->headers;
287 while(e != NULL) {
288 pdkim_stringlist *c = e;
289 if (e->value != NULL) free(e->value);
290 e = e->next;
291 free(c);
292 }
293
294 if (sig->sigdata != NULL) free(sig->sigdata);
295 if (sig->bodyhash != NULL) free(sig->bodyhash);
296 if (sig->selector != NULL) free(sig->selector);
297 if (sig->domain != NULL) free(sig->domain);
298 if (sig->identity != NULL) free(sig->identity);
299 if (sig->headernames != NULL) free(sig->headernames);
300 if (sig->copiedheaders != NULL) free(sig->copiedheaders);
301 if (sig->rsa_privkey != NULL) free(sig->rsa_privkey);
302 if (sig->sign_headers != NULL) free(sig->sign_headers);
303 if (sig->signature_header != NULL) free(sig->signature_header);
304 if (sig->sha1_body != NULL) free(sig->sha1_body);
305 if (sig->sha2_body != NULL) free(sig->sha2_body);
306 if (sig->hnames_check != NULL) free(sig->hnames_check);
307
308 if (sig->pubkey != NULL) pdkim_free_pubkey(sig->pubkey);
309
310 free(sig);
311 if (next != NULL) pdkim_free_sig(next);
312 }
313 }
314
315
316 /* -------------------------------------------------------------------------- */
317 DLLEXPORT void pdkim_free_ctx(pdkim_ctx *ctx) {
318 if (ctx) {
319 pdkim_free_sig(ctx->sig);
320 pdkim_strfree(ctx->cur_header);
321 free(ctx);
322 }
323 }
324
325
326 /* -------------------------------------------------------------------------- */
327 /* Matches the name of the passed raw "header" against
328 the passed colon-separated "list", starting at entry
329 "start". Returns the position of the header name in
330 the list. */
331 int header_name_match(char *header,
332 char *tick,
333 int do_tick) {
334 char *hname;
335 char *lcopy;
336 char *p;
337 char *q;
338 int rc = PDKIM_FAIL;
339
340 /* Get header name */
341 char *hcolon = strchr(header,':');
342 if (hcolon == NULL) return rc; /* This isn't a header */
343 hname = malloc((hcolon-header)+1);
344 if (hname == NULL) return PDKIM_ERR_OOM;
345 memset(hname,0,(hcolon-header)+1);
346 strncpy(hname,header,(hcolon-header));
347
348 /* Copy tick-off list locally, so we can punch zeroes into it */
349 lcopy = strdup(tick);
350 if (lcopy == NULL) {
351 free(hname);
352 return PDKIM_ERR_OOM;
353 }
354 p = lcopy;
355 q = strchr(p,':');
356 while (q != NULL) {
357 *q = '\0';
358
359 if (strcasecmp(p,hname) == 0) {
360 rc = PDKIM_OK;
361 /* Invalidate header name instance in tick-off list */
362 if (do_tick) tick[p-lcopy] = '_';
363 goto BAIL;
364 }
365
366 p = q+1;
367 q = strchr(p,':');
368 }
369
370 if (strcasecmp(p,hname) == 0) {
371 rc = PDKIM_OK;
372 /* Invalidate header name instance in tick-off list */
373 if (do_tick) tick[p-lcopy] = '_';
374 }
375
376 BAIL:
377 free(hname);
378 free(lcopy);
379 return rc;
380 }
381
382
383 /* -------------------------------------------------------------------------- */
384 /* Performs "relaxed" canonicalization of a header. The returned pointer needs
385 to be free()d. */
386 char *pdkim_relax_header (char *header, int crlf) {
387 int past_field_name = 0;
388 int seen_wsp = 0;
389 char *p = header;
390 char *q;
391 char *relaxed = malloc(strlen(header)+3);
392 if (relaxed == NULL) return NULL;
393 q = relaxed;
394 while (*p != '\0') {
395 int c = *p;
396 /* Ignore CR & LF */
397 if ( (c == '\r') || (c == '\n') ) {
398 p++;
399 continue;
400 }
401 if ( (c == '\t') || (c == ' ') ) {
402 c = ' '; /* Turns WSP into SP */
403 if (seen_wsp) {
404 p++;
405 continue;
406 }
407 else seen_wsp = 1;
408 }
409 else {
410 if ( (!past_field_name) && (c == ':') ) {
411 if (seen_wsp) q--; /* This removes WSP before the colon */
412 seen_wsp = 1; /* This removes WSP after the colon */
413 past_field_name = 1;
414 }
415 else seen_wsp = 0;
416 }
417 /* Lowercase header name */
418 if (!past_field_name) c = tolower(c);
419 *q = c;
420 p++;
421 q++;
422 }
423 if (seen_wsp) q--;
424 *q = '\0';
425 if (crlf) strcat(relaxed,"\r\n");
426 return relaxed;
427 }
428
429
430 /* -------------------------------------------------------------------------- */
431 #define PDKIM_QP_ERROR_DECODE -1
432 char *pdkim_decode_qp_char(char *qp_p, int *c) {
433 char *initial_pos = qp_p;
434
435 /* Advance one char */
436 qp_p++;
437
438 /* Check for two hex digits and decode them */
439 if (isxdigit(*qp_p) && isxdigit(qp_p[1])) {
440 /* Do hex conversion */
441 if (isdigit(*qp_p)) {*c = *qp_p - '0';}
442 else {*c = toupper(*qp_p) - 'A' + 10;}
443 *c <<= 4;
444 if (isdigit(qp_p[1])) {*c |= qp_p[1] - '0';}
445 else {*c |= toupper(qp_p[1]) - 'A' + 10;}
446 return qp_p + 2;
447 }
448
449 /* Illegal char here */
450 *c = PDKIM_QP_ERROR_DECODE;
451 return initial_pos;
452 }
453
454
455 /* -------------------------------------------------------------------------- */
456 char *pdkim_decode_qp(char *str) {
457 int nchar = 0;
458 char *q;
459 char *p = str;
460 char *n = malloc(strlen(p)+1);
461 if (n == NULL) return NULL;
462 *n = '\0';
463 q = n;
464 while (*p != '\0') {
465 if (*p == '=') {
466 p = pdkim_decode_qp_char(p,&nchar);
467 if (nchar >= 0) {
468 *q = nchar;
469 q++;
470 continue;
471 }
472 }
473 else {
474 *q = *p;
475 q++;
476 }
477 p++;
478 }
479 *q = '\0';
480 return n;
481 }
482
483
484 /* -------------------------------------------------------------------------- */
485 char *pdkim_decode_base64(char *str, int *num_decoded) {
486 int dlen = 0;
487 char *res;
488
489 base64_decode(NULL, &dlen, (unsigned char *)str, strlen(str));
490 res = malloc(dlen+1);
491 if (res == NULL) return NULL;
492 if (base64_decode((unsigned char *)res,&dlen,(unsigned char *)str,strlen(str)) != 0) {
493 free(res);
494 return NULL;
495 }
496 if (num_decoded != NULL) *num_decoded = dlen;
497 return res;
498 }
499
500 /* -------------------------------------------------------------------------- */
501 char *pdkim_encode_base64(char *str, int num) {
502 int dlen = 0;
503 char *res;
504
505 base64_encode(NULL, &dlen, (unsigned char *)str, num);
506 res = malloc(dlen+1);
507 if (res == NULL) return NULL;
508 if (base64_encode((unsigned char *)res,&dlen,(unsigned char *)str,num) != 0) {
509 free(res);
510 return NULL;
511 }
512 return res;
513 }
514
515
516 /* -------------------------------------------------------------------------- */
517 #define PDKIM_HDR_LIMBO 0
518 #define PDKIM_HDR_TAG 1
519 #define PDKIM_HDR_VALUE 2
520 pdkim_signature *pdkim_parse_sig_header(pdkim_ctx *ctx, char *raw_hdr) {
521 pdkim_signature *sig ;
522 char *p,*q;
523 pdkim_str *cur_tag = NULL;
524 pdkim_str *cur_val = NULL;
525 int past_hname = 0;
526 int in_b_val = 0;
527 int where = PDKIM_HDR_LIMBO;
528 int i;
529
530 sig = malloc(sizeof(pdkim_signature));
531 if (sig == NULL) return NULL;
532 memset(sig,0,sizeof(pdkim_signature));
533 sig->bodylength = -1;
534
535 sig->rawsig_no_b_val = malloc(strlen(raw_hdr)+1);
536 if (sig->rawsig_no_b_val == NULL) {
537 free(sig);
538 return NULL;
539 }
540
541 p = raw_hdr;
542 q = sig->rawsig_no_b_val;
543
544 while (1) {
545
546 /* Ignore FWS */
547 if ( (*p == '\r') || (*p == '\n') )
548 goto NEXT_CHAR;
549
550 /* Fast-forward through header name */
551 if (!past_hname) {
552 if (*p == ':') past_hname = 1;
553 goto NEXT_CHAR;
554 }
555
556 if (where == PDKIM_HDR_LIMBO) {
557 /* In limbo, just wait for a tag-char to appear */
558 if (!((*p >= 'a') && (*p <= 'z')))
559 goto NEXT_CHAR;
560
561 where = PDKIM_HDR_TAG;
562 }
563
564 if (where == PDKIM_HDR_TAG) {
565 if (cur_tag == NULL)
566 cur_tag = pdkim_strnew(NULL);
567
568 if ((*p >= 'a') && (*p <= 'z'))
569 pdkim_strncat(cur_tag,p,1);
570
571 if (*p == '=') {
572 if (strcmp(cur_tag->str,"b") == 0) {
573 *q = '='; q++;
574 in_b_val = 1;
575 }
576 where = PDKIM_HDR_VALUE;
577 goto NEXT_CHAR;
578 }
579 }
580
581 if (where == PDKIM_HDR_VALUE) {
582 if (cur_val == NULL)
583 cur_val = pdkim_strnew(NULL);
584
585 if ( (*p == '\r') || (*p == '\n') || (*p == ' ') || (*p == '\t') )
586 goto NEXT_CHAR;
587
588 if ( (*p == ';') || (*p == '\0') ) {
589 if (cur_tag->len > 0) {
590 pdkim_strtrim(cur_val);
591 #ifdef PDKIM_DEBUG
592 if (ctx->debug_stream)
593 fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str);
594 #endif
595 switch (cur_tag->str[0]) {
596 case 'b':
597 switch (cur_tag->str[1]) {
598 case 'h':
599 sig->bodyhash = pdkim_decode_base64(cur_val->str,&(sig->bodyhash_len));
600 break;
601 default:
602 sig->sigdata = pdkim_decode_base64(cur_val->str,&(sig->sigdata_len));
603 break;
604 }
605 break;
606 case 'v':
607 if (strcmp(cur_val->str,PDKIM_SIGNATURE_VERSION) == 0) {
608 /* We only support version 1, and that is currently the
609 only version there is. */
610 sig->version = 1;
611 }
612 break;
613 case 'a':
614 i = 0;
615 while (pdkim_algos[i] != NULL) {
616 if (strcmp(cur_val->str,pdkim_algos[i]) == 0 ) {
617 sig->algo = i;
618 break;
619 }
620 i++;
621 }
622 break;
623 case 'c':
624 i = 0;
625 while (pdkim_combined_canons[i].str != NULL) {
626 if (strcmp(cur_val->str,pdkim_combined_canons[i].str) == 0 ) {
627 sig->canon_headers = pdkim_combined_canons[i].canon_headers;
628 sig->canon_body = pdkim_combined_canons[i].canon_body;
629 break;
630 }
631 i++;
632 }
633 break;
634 case 'q':
635 i = 0;
636 while (pdkim_querymethods[i] != NULL) {
637 if (strcmp(cur_val->str,pdkim_querymethods[i]) == 0 ) {
638 sig->querymethod = i;
639 break;
640 }
641 i++;
642 }
643 break;
644 case 's':
645 sig->selector = strdup(cur_val->str);
646 break;
647 case 'd':
648 sig->domain = strdup(cur_val->str);
649 break;
650 case 'i':
651 sig->identity = pdkim_decode_qp(cur_val->str);
652 break;
653 case 't':
654 sig->created = strtoul(cur_val->str,NULL,10);
655 break;
656 case 'x':
657 sig->expires = strtoul(cur_val->str,NULL,10);
658 break;
659 case 'l':
660 sig->bodylength = strtol(cur_val->str,NULL,10);
661 break;
662 case 'h':
663 sig->headernames = strdup(cur_val->str);
664 break;
665 case 'z':
666 sig->copiedheaders = pdkim_decode_qp(cur_val->str);
667 break;
668 default:
669 #ifdef PDKIM_DEBUG
670 if (ctx->debug_stream)
671 fprintf(ctx->debug_stream, "Unknown tag encountered\n");
672 #endif
673 break;
674 }
675 }
676 pdkim_strclear(cur_tag);
677 pdkim_strclear(cur_val);
678 in_b_val = 0;
679 where = PDKIM_HDR_LIMBO;
680 goto NEXT_CHAR;
681 }
682 else pdkim_strncat(cur_val,p,1);
683 }
684
685 NEXT_CHAR:
686 if (*p == '\0') break;
687
688 if (!in_b_val) {
689 *q = *p;
690 q++;
691 }
692 p++;
693 }
694
695 /* Make sure the most important bits are there. */
696 if (!(sig->domain && (*(sig->domain) != '\0') &&
697 sig->selector && (*(sig->selector) != '\0') &&
698 sig->headernames && (*(sig->headernames) != '\0') &&
699 sig->bodyhash &&
700 sig->sigdata &&
701 sig->version)) {
702 pdkim_free_sig(sig);
703 return NULL;
704 }
705
706 /* Copy header list to 'tick-off' header list */
707 sig->hnames_check = strdup(sig->headernames);
708
709 *q = '\0';
710 /* Chomp raw header. The final newline must not be added to the signature. */
711 q--;
712 while( (q > sig->rawsig_no_b_val) && ((*q == '\r') || (*q == '\n')) ) {
713 *q = '\0'; q--;
714 }
715
716 #ifdef PDKIM_DEBUG
717 if (ctx->debug_stream) {
718 fprintf(ctx->debug_stream,
719 "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
720 pdkim_quoteprint(ctx->debug_stream,
721 sig->rawsig_no_b_val,
722 strlen(sig->rawsig_no_b_val), 1);
723 fprintf(ctx->debug_stream,
724 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
725 }
726 #endif
727
728 sig->sha1_body = malloc(sizeof(sha1_context));
729 if (sig->sha1_body == NULL) {
730 pdkim_free_sig(sig);
731 return NULL;
732 }
733 sig->sha2_body = malloc(sizeof(sha2_context));
734 if (sig->sha2_body == NULL) {
735 pdkim_free_sig(sig);
736 return NULL;
737 }
738
739 sha1_starts(sig->sha1_body);
740 sha2_starts(sig->sha2_body,0);
741
742 return sig;
743 }
744
745
746 /* -------------------------------------------------------------------------- */
747 pdkim_pubkey *pdkim_parse_pubkey_record(pdkim_ctx *ctx, char *raw_record) {
748 pdkim_pubkey *pub ;
749 char *p;
750 pdkim_str *cur_tag = NULL;
751 pdkim_str *cur_val = NULL;
752 int where = PDKIM_HDR_LIMBO;
753
754 pub = malloc(sizeof(pdkim_pubkey));
755 if (pub == NULL) return NULL;
756 memset(pub,0,sizeof(pdkim_pubkey));
757
758 p = raw_record;
759
760 while (1) {
761
762 /* Ignore FWS */
763 if ( (*p == '\r') || (*p == '\n') )
764 goto NEXT_CHAR;
765
766 if (where == PDKIM_HDR_LIMBO) {
767 /* In limbo, just wait for a tag-char to appear */
768 if (!((*p >= 'a') && (*p <= 'z')))
769 goto NEXT_CHAR;
770
771 where = PDKIM_HDR_TAG;
772 }
773
774 if (where == PDKIM_HDR_TAG) {
775 if (cur_tag == NULL)
776 cur_tag = pdkim_strnew(NULL);
777
778 if ((*p >= 'a') && (*p <= 'z'))
779 pdkim_strncat(cur_tag,p,1);
780
781 if (*p == '=') {
782 where = PDKIM_HDR_VALUE;
783 goto NEXT_CHAR;
784 }
785 }
786
787 if (where == PDKIM_HDR_VALUE) {
788 if (cur_val == NULL)
789 cur_val = pdkim_strnew(NULL);
790
791 if ( (*p == '\r') || (*p == '\n') )
792 goto NEXT_CHAR;
793
794 if ( (*p == ';') || (*p == '\0') ) {
795 if (cur_tag->len > 0) {
796 pdkim_strtrim(cur_val);
797 #ifdef PDKIM_DEBUG
798 if (ctx->debug_stream)
799 fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str);
800 #endif
801 switch (cur_tag->str[0]) {
802 case 'v':
803 /* This tag isn't evaluated because:
804 - We only support version DKIM1.
805 - Which is the default for this value (set below)
806 - Other versions are currently not specified. */
807 break;
808 case 'h':
809 pub->hashes = strdup(cur_val->str);
810 break;
811 case 'g':
812 pub->granularity = strdup(cur_val->str);
813 break;
814 case 'n':
815 pub->notes = pdkim_decode_qp(cur_val->str);
816 break;
817 case 'p':
818 pub->key = pdkim_decode_base64(cur_val->str,&(pub->key_len));
819 break;
820 case 'k':
821 pub->hashes = strdup(cur_val->str);
822 break;
823 case 's':
824 pub->srvtype = strdup(cur_val->str);
825 break;
826 case 't':
827 if (strchr(cur_val->str,'y') != NULL) pub->testing = 1;
828 if (strchr(cur_val->str,'s') != NULL) pub->no_subdomaining = 1;
829 break;
830 default:
831 #ifdef PDKIM_DEBUG
832 if (ctx->debug_stream)
833 fprintf(ctx->debug_stream, "Unknown tag encountered\n");
834 #endif
835 break;
836 }
837 }
838 pdkim_strclear(cur_tag);
839 pdkim_strclear(cur_val);
840 where = PDKIM_HDR_LIMBO;
841 goto NEXT_CHAR;
842 }
843 else pdkim_strncat(cur_val,p,1);
844 }
845
846 NEXT_CHAR:
847 if (*p == '\0') break;
848 p++;
849 }
850
851 /* Set fallback defaults */
852 if (pub->version == NULL) pub->version = strdup(PDKIM_PUB_RECORD_VERSION);
853 if (pub->granularity == NULL) pub->granularity = strdup("*");
854 if (pub->keytype == NULL) pub->keytype = strdup("rsa");
855 if (pub->srvtype == NULL) pub->srvtype = strdup("*");
856
857 /* p= is required */
858 if (pub->key == NULL) {
859 pdkim_free_pubkey(pub);
860 return NULL;
861 }
862
863 return pub;
864 }
865
866
867 /* -------------------------------------------------------------------------- */
868 int pdkim_update_bodyhash(pdkim_ctx *ctx, char *data, int len) {
869 pdkim_signature *sig = ctx->sig;
870 /* Cache relaxed version of data */
871 char *relaxed_data = NULL;
872 int relaxed_len = 0;
873
874 /* Traverse all signatures, updating their hashes. */
875 while (sig != NULL) {
876 /* Defaults to simple canon (no further treatment necessary) */
877 char *canon_data = data;
878 int canon_len = len;
879
880 if (sig->canon_body == PDKIM_CANON_RELAXED) {
881 /* Relax the line if not done already */
882 if (relaxed_data == NULL) {
883 int seen_wsp = 0;
884 char *p = data;
885 int q = 0;
886 relaxed_data = malloc(len+1);
887 if (relaxed_data == NULL) return PDKIM_ERR_OOM;
888 while (*p != '\0') {
889 char c = *p;
890 if (c == '\r') {
891 if ( (q > 0) && (relaxed_data[q-1] == ' ') ) q--;
892 }
893 else if ( (c == '\t') || (c == ' ') ) {
894 c = ' '; /* Turns WSP into SP */
895 if (seen_wsp) {
896 p++;
897 continue;
898 }
899 else seen_wsp = 1;
900 }
901 else seen_wsp = 0;
902 relaxed_data[q++] = c;
903 p++;
904 }
905 relaxed_data[q] = '\0';
906 relaxed_len = q;
907 }
908 canon_data = relaxed_data;
909 canon_len = relaxed_len;
910 }
911
912 /* Make sure we don't exceed the to-be-signed body length */
913 if ((sig->bodylength >= 0) &&
914 ((sig->signed_body_bytes+(unsigned long)canon_len) > sig->bodylength))
915 canon_len = (sig->bodylength - sig->signed_body_bytes);
916
917 if (canon_len > 0) {
918 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
919 sha1_update(sig->sha1_body,(unsigned char *)canon_data,canon_len);
920 else
921 sha2_update(sig->sha2_body,(unsigned char *)canon_data,canon_len);
922 sig->signed_body_bytes += canon_len;
923 #ifdef PDKIM_DEBUG
924 if (ctx->debug_stream!=NULL)
925 pdkim_quoteprint(ctx->debug_stream,canon_data,canon_len,0);
926 #endif
927 }
928
929 sig = sig->next;
930 }
931
932 if (relaxed_data != NULL) free(relaxed_data);
933 return PDKIM_OK;
934 }
935
936
937 /* -------------------------------------------------------------------------- */
938 int pdkim_finish_bodyhash(pdkim_ctx *ctx) {
939 pdkim_signature *sig = ctx->sig;
940
941 /* Traverse all signatures */
942 while (sig != NULL) {
943
944 /* Finish hashes */
945 unsigned char bh[32]; /* SHA-256 = 32 Bytes, SHA-1 = 20 Bytes */
946 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
947 sha1_finish(sig->sha1_body,bh);
948 else
949 sha2_finish(sig->sha2_body,bh);
950
951 #ifdef PDKIM_DEBUG
952 if (ctx->debug_stream) {
953 fprintf(ctx->debug_stream, "PDKIM [%s] Body bytes hashed: %lu\n",
954 sig->domain, sig->signed_body_bytes);
955 fprintf(ctx->debug_stream, "PDKIM [%s] bh computed: ", sig->domain);
956 pdkim_hexprint(ctx->debug_stream, (char *)bh,
957 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1);
958 }
959 #endif
960
961 /* SIGNING -------------------------------------------------------------- */
962 if (ctx->mode == PDKIM_MODE_SIGN) {
963 sig->bodyhash_len = (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32;
964 sig->bodyhash = malloc(sig->bodyhash_len);
965 if (sig->bodyhash == NULL) return PDKIM_ERR_OOM;
966 memcpy(sig->bodyhash,bh,sig->bodyhash_len);
967
968 /* If bodylength limit is set, and we have received less bytes
969 than the requested amount, effectively remove the limit tag. */
970 if (sig->signed_body_bytes < sig->bodylength) sig->bodylength = -1;
971 }
972 /* VERIFICATION --------------------------------------------------------- */
973 else {
974 /* Compare bodyhash */
975 if (memcmp(bh,sig->bodyhash,
976 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32) == 0) {
977 #ifdef PDKIM_DEBUG
978 if (ctx->debug_stream)
979 fprintf(ctx->debug_stream, "PDKIM [%s] Body hash verified OK\n",
980 sig->domain);
981 #endif
982 }
983 else {
984 #ifdef PDKIM_DEBUG
985 if (ctx->debug_stream) {
986 fprintf(ctx->debug_stream, "PDKIM [%s] Body hash did NOT verify\n",
987 sig->domain);
988 fprintf(ctx->debug_stream, "PDKIM [%s] bh signature: ", sig->domain);
989 pdkim_hexprint(ctx->debug_stream, sig->bodyhash,
990 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1);
991 }
992 #endif
993 sig->verify_status = PDKIM_VERIFY_FAIL;
994 sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY;
995 }
996 }
997
998 sig = sig->next;
999 }
1000
1001 return PDKIM_OK;
1002 }
1003
1004
1005
1006 /* -------------------------------------------------------------------------- */
1007 /* Callback from pdkim_feed below for processing complete body lines */
1008 int pdkim_bodyline_complete(pdkim_ctx *ctx) {
1009 char *p = ctx->linebuf;
1010 int n = ctx->linebuf_offset;
1011
1012 /* Ignore extra data if we've seen the end-of-data marker */
1013 if (ctx->seen_eod) goto BAIL;
1014
1015 /* We've always got one extra byte to stuff a zero ... */
1016 ctx->linebuf[(ctx->linebuf_offset)] = '\0';
1017
1018 if (ctx->input_mode == PDKIM_INPUT_SMTP) {
1019 /* Terminate on EOD marker */
1020 if (memcmp(p,".\r\n",3) == 0) {
1021 ctx->seen_eod = 1;
1022 goto BAIL;
1023 }
1024 /* Unstuff dots */
1025 if (memcmp(p,"..",2) == 0) {
1026 p++;
1027 n--;
1028 }
1029 }
1030
1031 /* Empty lines need to be buffered until we find a non-empty line */
1032 if (memcmp(p,"\r\n",2) == 0) {
1033 ctx->num_buffered_crlf++;
1034 goto BAIL;
1035 }
1036
1037 /* At this point, we have a non-empty line, so release the buffered ones. */
1038 while (ctx->num_buffered_crlf) {
1039 pdkim_update_bodyhash(ctx,"\r\n",2);
1040 ctx->num_buffered_crlf--;
1041 }
1042
1043 pdkim_update_bodyhash(ctx,p,n);
1044
1045 BAIL:
1046 ctx->linebuf_offset = 0;
1047 return PDKIM_OK;
1048 }
1049
1050
1051 /* -------------------------------------------------------------------------- */
1052 /* Callback from pdkim_feed below for processing complete headers */
1053 #define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:"
1054 int pdkim_header_complete(pdkim_ctx *ctx) {
1055 pdkim_signature *sig = ctx->sig;
1056
1057 /* Special case: The last header can have an extra \r appended */
1058 if ( (ctx->cur_header->len > 1) &&
1059 (ctx->cur_header->str[(ctx->cur_header->len)-1] == '\r') ) {
1060 ctx->cur_header->str[(ctx->cur_header->len)-1] = '\0';
1061 ctx->cur_header->len--;
1062 }
1063
1064 ctx->num_headers++;
1065 if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
1066
1067 /* Traverse all signatures */
1068 while (sig != NULL) {
1069 pdkim_stringlist *list;
1070
1071 /* SIGNING -------------------------------------------------------------- */
1072 if (ctx->mode == PDKIM_MODE_SIGN) {
1073 if (header_name_match(ctx->cur_header->str,
1074 sig->sign_headers?
1075 sig->sign_headers:
1076 PDKIM_DEFAULT_SIGN_HEADERS, 0) != PDKIM_OK) goto NEXT_SIG;
1077 }
1078 /* VERIFICATION --------------------------------------------------------- */
1079 else {
1080 /* Header is not included or all instances were already 'ticked off' */
1081 if (header_name_match(ctx->cur_header->str,
1082 sig->hnames_check, 1) != PDKIM_OK) goto NEXT_SIG;
1083 }
1084
1085 /* Add header to the signed headers list (in reverse order) */
1086 list = pdkim_prepend_stringlist(sig->headers,
1087 ctx->cur_header->str);
1088 if (list == NULL) return PDKIM_ERR_OOM;
1089 sig->headers = list;
1090
1091 NEXT_SIG:
1092 sig = sig->next;
1093 }
1094
1095 /* DKIM-Signature: headers are added to the verification list */
1096 if ( (ctx->mode == PDKIM_MODE_VERIFY) &&
1097 (strncasecmp(ctx->cur_header->str,
1098 DKIM_SIGNATURE_HEADERNAME,
1099 strlen(DKIM_SIGNATURE_HEADERNAME)) == 0) ) {
1100 pdkim_signature *new_sig;
1101 /* Create and chain new signature block */
1102 #ifdef PDKIM_DEBUG
1103 if (ctx->debug_stream)
1104 fprintf(ctx->debug_stream,
1105 "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1106 #endif
1107 new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header->str);
1108 if (new_sig != NULL) {
1109 pdkim_signature *last_sig = ctx->sig;
1110 if (last_sig == NULL) {
1111 ctx->sig = new_sig;
1112 }
1113 else {
1114 while (last_sig->next != NULL) { last_sig = last_sig->next; }
1115 last_sig->next = new_sig;
1116 }
1117 }
1118 else {
1119 #ifdef PDKIM_DEBUG
1120 if (ctx->debug_stream) {
1121 fprintf(ctx->debug_stream,"Error while parsing signature header\n");
1122 fprintf(ctx->debug_stream,
1123 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1124 }
1125 #endif
1126 }
1127 }
1128
1129 BAIL:
1130 pdkim_strclear(ctx->cur_header); /* Re-use existing pdkim_str */
1131 return PDKIM_OK;
1132 }
1133
1134
1135
1136 /* -------------------------------------------------------------------------- */
1137 #define HEADER_BUFFER_FRAG_SIZE 256
1138 DLLEXPORT int pdkim_feed (pdkim_ctx *ctx,
1139 char *data,
1140 int len) {
1141 int p;
1142 for (p=0;p<len;p++) {
1143 char c = data[p];
1144 if (ctx->past_headers) {
1145 /* Processing body byte */
1146 ctx->linebuf[(ctx->linebuf_offset)++] = c;
1147 if (c == '\n') {
1148 int rc = pdkim_bodyline_complete(ctx); /* End of line */
1149 if (rc != PDKIM_OK) return rc;
1150 }
1151 if (ctx->linebuf_offset == (PDKIM_MAX_BODY_LINE_LEN-1))
1152 return PDKIM_ERR_LONG_LINE;
1153 }
1154 else {
1155 /* Processing header byte */
1156 if (c != '\r') {
1157 if (c == '\n') {
1158 if (ctx->seen_lf) {
1159 int rc = pdkim_header_complete(ctx); /* Seen last header line */
1160 if (rc != PDKIM_OK) return rc;
1161 ctx->past_headers = 1;
1162 ctx->seen_lf = 0;
1163 #ifdef PDKIM_DEBUG
1164 if (ctx->debug_stream)
1165 fprintf(ctx->debug_stream,
1166 "PDKIM >> Hashed body data, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1167 #endif
1168 continue;
1169 }
1170 else ctx->seen_lf = 1;
1171 }
1172 else if (ctx->seen_lf) {
1173 if (! ((c == '\t') || (c == ' '))) {
1174 int rc = pdkim_header_complete(ctx); /* End of header */
1175 if (rc != PDKIM_OK) return rc;
1176 }
1177 ctx->seen_lf = 0;
1178 }
1179 }
1180 if (ctx->cur_header == NULL) {
1181 ctx->cur_header = pdkim_strnew(NULL);
1182 if (ctx->cur_header == NULL) return PDKIM_ERR_OOM;
1183 }
1184 if (ctx->cur_header->len < PDKIM_MAX_HEADER_LEN)
1185 if (pdkim_strncat(ctx->cur_header,&data[p],1) == NULL)
1186 return PDKIM_ERR_OOM;
1187 }
1188 }
1189 return PDKIM_OK;
1190 }
1191
1192
1193 /* -------------------------------------------------------------------------- */
1194 char *pdkim_create_header(pdkim_signature *sig, int final) {
1195 char *rc = NULL;
1196 char *base64_bh = NULL;
1197 char *base64_b = NULL;
1198 pdkim_str *hdr = pdkim_strnew("DKIM-Signature: v="PDKIM_SIGNATURE_VERSION);
1199 if (hdr == NULL) return NULL;
1200
1201 base64_bh = pdkim_encode_base64(sig->bodyhash, sig->bodyhash_len);
1202 if (base64_bh == NULL) goto BAIL;
1203
1204 /* Required and static bits */
1205 if (
1206 pdkim_strcat(hdr,"; a=") &&
1207 pdkim_strcat(hdr,pdkim_algos[sig->algo]) &&
1208 pdkim_strcat(hdr,"; q=") &&
1209 pdkim_strcat(hdr,pdkim_querymethods[sig->querymethod]) &&
1210 pdkim_strcat(hdr,"; c=") &&
1211 pdkim_strcat(hdr,pdkim_canons[sig->canon_headers]) &&
1212 pdkim_strcat(hdr,"/") &&
1213 pdkim_strcat(hdr,pdkim_canons[sig->canon_body]) &&
1214 pdkim_strcat(hdr,"; d=") &&
1215 pdkim_strcat(hdr,sig->domain) &&
1216 pdkim_strcat(hdr,"; s=") &&
1217 pdkim_strcat(hdr,sig->selector) &&
1218 pdkim_strcat(hdr,";\r\n\th=") &&
1219 pdkim_strcat(hdr,sig->headernames) &&
1220 pdkim_strcat(hdr,"; bh=") &&
1221 pdkim_strcat(hdr,base64_bh) &&
1222 pdkim_strcat(hdr,";\r\n\t")
1223 ) {
1224 /* Optional bits */
1225 if (sig->identity != NULL) {
1226 if (!( pdkim_strcat(hdr,"i=") &&
1227 pdkim_strcat(hdr,sig->identity) &&
1228 pdkim_strcat(hdr,";") ) ) {
1229 goto BAIL;
1230 }
1231 }
1232 if (sig->created > 0) {
1233 if (!( pdkim_strcat(hdr,"t=") &&
1234 pdkim_numcat(hdr,sig->created) &&
1235 pdkim_strcat(hdr,";") ) ) {
1236 goto BAIL;
1237 }
1238 }
1239 if (sig->expires > 0) {
1240 if (!( pdkim_strcat(hdr,"x=") &&
1241 pdkim_numcat(hdr,sig->expires) &&
1242 pdkim_strcat(hdr,";") ) ) {
1243 goto BAIL;
1244 }
1245 }
1246 if (sig->bodylength >= 0) {
1247 if (!( pdkim_strcat(hdr,"l=") &&
1248 pdkim_numcat(hdr,sig->bodylength) &&
1249 pdkim_strcat(hdr,";") ) ) {
1250 goto BAIL;
1251 }
1252 }
1253 /* Extra linebreak */
1254 if (hdr->str[(hdr->len)-1] == ';') {
1255 if (!pdkim_strcat(hdr," \r\n\t")) goto BAIL;
1256 }
1257 /* Preliminary or final version? */
1258 if (final) {
1259 base64_b = pdkim_encode_base64(sig->sigdata, sig->sigdata_len);
1260 if (base64_b == NULL) goto BAIL;
1261 if (
1262 pdkim_strcat(hdr,"b=") &&
1263 pdkim_strcat(hdr,base64_b) &&
1264 pdkim_strcat(hdr,";")
1265 ) goto DONE;
1266 }
1267 else {
1268 if (pdkim_strcat(hdr,"b=;")) goto DONE;
1269 }
1270
1271 goto BAIL;
1272 }
1273
1274 DONE:
1275 rc = strdup(hdr->str);
1276
1277 BAIL:
1278 pdkim_strfree(hdr);
1279 if (base64_bh != NULL) free(base64_bh);
1280 if (base64_b != NULL) free(base64_b);
1281 return rc;
1282 }
1283
1284
1285 /* -------------------------------------------------------------------------- */
1286 DLLEXPORT int pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures) {
1287 pdkim_signature *sig = ctx->sig;
1288 pdkim_str *headernames = NULL; /* Collected signed header names */
1289
1290 /* Check if we must still flush a (partial) header. If that is the
1291 case, the message has no body, and we must compute a body hash
1292 out of '<CR><LF>' */
1293 if (ctx->cur_header && ctx->cur_header->len) {
1294 int rc = pdkim_header_complete(ctx);
1295 if (rc != PDKIM_OK) return rc;
1296 pdkim_update_bodyhash(ctx,"\r\n",2);
1297 }
1298 else {
1299 /* For non-smtp input, check if there's an unfinished line in the
1300 body line buffer. If that is the case, we must add a CRLF to the
1301 hash to properly terminate the message. */
1302 if ((ctx->input_mode == PDKIM_INPUT_NORMAL) && ctx->linebuf_offset) {
1303 pdkim_update_bodyhash(ctx, ctx->linebuf, ctx->linebuf_offset);
1304 pdkim_update_bodyhash(ctx,"\r\n",2);
1305 }
1306 #ifdef PDKIM_DEBUG
1307 if (ctx->debug_stream)
1308 fprintf(ctx->debug_stream,
1309 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1310 #endif
1311 }
1312
1313 /* Build (and/or evaluate) body hash */
1314 if (pdkim_finish_bodyhash(ctx) != PDKIM_OK) return PDKIM_ERR_OOM;
1315
1316 /* SIGNING -------------------------------------------------------------- */
1317 if (ctx->mode == PDKIM_MODE_SIGN) {
1318 headernames = pdkim_strnew(NULL);
1319 if (headernames == NULL) return PDKIM_ERR_OOM;
1320 }
1321 /* ---------------------------------------------------------------------- */
1322
1323 while (sig != NULL) {
1324 sha1_context sha1_headers;
1325 sha2_context sha2_headers;
1326 char *sig_hdr;
1327 char headerhash[32];
1328
1329 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1330 sha1_starts(&sha1_headers);
1331 else
1332 sha2_starts(&sha2_headers,0);
1333
1334 #ifdef PDKIM_DEBUG
1335 if (ctx->debug_stream)
1336 fprintf(ctx->debug_stream,
1337 "PDKIM >> Hashed header data, canonicalized, in sequence >>>>>>>>>>>>>>\n");
1338 #endif
1339
1340 /* SIGNING ---------------------------------------------------------------- */
1341 /* When signing, walk through our header list and add them to the hash. As we
1342 go, construct a list of the header's names to use for the h= parameter. */
1343 if (ctx->mode == PDKIM_MODE_SIGN) {
1344 pdkim_stringlist *p = sig->headers;
1345 while (p != NULL) {
1346 char *rh = NULL;
1347 /* Collect header names (Note: colon presence is guaranteed here) */
1348 char *q = strchr(p->value,':');
1349 if (pdkim_strncat(headernames, p->value,
1350 (q-(p->value))+((p->next==NULL)?0:1)) == NULL)
1351 return PDKIM_ERR_OOM;
1352
1353 if (sig->canon_headers == PDKIM_CANON_RELAXED)
1354 rh = pdkim_relax_header(p->value,1); /* cook header for relaxed canon */
1355 else
1356 rh = strdup(p->value); /* just copy it for simple canon */
1357
1358 if (rh == NULL) return PDKIM_ERR_OOM;
1359
1360 /* Feed header to the hash algorithm */
1361 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1362 sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh));
1363 else
1364 sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh));
1365 #ifdef PDKIM_DEBUG
1366 if (ctx->debug_stream)
1367 pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1);
1368 #endif
1369 free(rh);
1370 p = p->next;
1371 }
1372 }
1373 /* VERIFICATION ----------------------------------------------------------- */
1374 /* When verifying, walk through the header name list in the h= parameter and
1375 add the headers to the hash in that order. */
1376 else {
1377 char *b = strdup(sig->headernames);
1378 char *p = b;
1379 char *q = NULL;
1380 if (b == NULL) return PDKIM_ERR_OOM;
1381
1382 while(1) {
1383 pdkim_stringlist *hdrs = sig->headers;
1384 q = strchr(p,':');
1385 if (q != NULL) *q = '\0';
1386 while (hdrs != NULL) {
1387 if ( (strncasecmp(hdrs->value,p,strlen(p)) == 0) &&
1388 ((hdrs->value)[strlen(p)] == ':') ) {
1389 char *rh = NULL;
1390 if (sig->canon_headers == PDKIM_CANON_RELAXED)
1391 rh = pdkim_relax_header(hdrs->value,1); /* cook header for relaxed canon */
1392 else
1393 rh = strdup(hdrs->value); /* just copy it for simple canon */
1394 if (rh == NULL) return PDKIM_ERR_OOM;
1395 /* Feed header to the hash algorithm */
1396 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1397 sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh));
1398 else
1399 sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh));
1400 #ifdef PDKIM_DEBUG
1401 if (ctx->debug_stream)
1402 pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1);
1403 #endif
1404 free(rh);
1405 (hdrs->value)[0] = '_';
1406 break;
1407 }
1408 hdrs = hdrs->next;
1409 }
1410 if (q == NULL) break;
1411 p = q+1;
1412 }
1413 free(b);
1414 }
1415
1416 #ifdef PDKIM_DEBUG
1417 if (ctx->debug_stream)
1418 fprintf(ctx->debug_stream,
1419 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1420 #endif
1421
1422 /* SIGNING ---------------------------------------------------------------- */
1423 if (ctx->mode == PDKIM_MODE_SIGN) {
1424 /* Copy headernames to signature struct */
1425 sig->headernames = strdup(headernames->str);
1426 pdkim_strfree(headernames);
1427
1428 /* Create signature header with b= omitted */
1429 sig_hdr = pdkim_create_header(ctx->sig,0);
1430 }
1431 /* VERIFICATION ----------------------------------------------------------- */
1432 else {
1433 sig_hdr = strdup(sig->rawsig_no_b_val);
1434 }
1435 /* ------------------------------------------------------------------------ */
1436
1437 if (sig_hdr == NULL) return PDKIM_ERR_OOM;
1438
1439 /* Relax header if necessary */
1440 if (sig->canon_headers == PDKIM_CANON_RELAXED) {
1441 char *relaxed_hdr = pdkim_relax_header(sig_hdr,0);
1442 free(sig_hdr);
1443 if (relaxed_hdr == NULL) return PDKIM_ERR_OOM;
1444 sig_hdr = relaxed_hdr;
1445 }
1446
1447 #ifdef PDKIM_DEBUG
1448 if (ctx->debug_stream) {
1449 fprintf(ctx->debug_stream,
1450 "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
1451 pdkim_quoteprint(ctx->debug_stream, sig_hdr, strlen(sig_hdr), 1);
1452 fprintf(ctx->debug_stream,
1453 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1454 }
1455 #endif
1456
1457 /* Finalize header hash */
1458 if (sig->algo == PDKIM_ALGO_RSA_SHA1) {
1459 sha1_update(&(sha1_headers),(unsigned char *)sig_hdr,strlen(sig_hdr));
1460 sha1_finish(&(sha1_headers),(unsigned char *)headerhash);
1461 #ifdef PDKIM_DEBUG
1462 if (ctx->debug_stream) {
1463 fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain);
1464 pdkim_hexprint(ctx->debug_stream, headerhash, 20, 1);
1465 }
1466 #endif
1467 }
1468 else {
1469 sha2_update(&(sha2_headers),(unsigned char *)sig_hdr,strlen(sig_hdr));
1470 sha2_finish(&(sha2_headers),(unsigned char *)headerhash);
1471 #ifdef PDKIM_DEBUG
1472 if (ctx->debug_stream) {
1473 fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain);
1474 pdkim_hexprint(ctx->debug_stream, headerhash, 32, 1);
1475 }
1476 #endif
1477 }
1478
1479 free(sig_hdr);
1480
1481 /* SIGNING ---------------------------------------------------------------- */
1482 if (ctx->mode == PDKIM_MODE_SIGN) {
1483 rsa_context rsa;
1484
1485 rsa_init(&rsa,RSA_PKCS_V15,0,NULL,NULL);
1486
1487 /* Perform private key operation */
1488 if (rsa_parse_key(&rsa, (unsigned char *)sig->rsa_privkey,
1489 strlen(sig->rsa_privkey), NULL, 0) != 0) {
1490 return PDKIM_ERR_RSA_PRIVKEY;
1491 }
1492
1493 sig->sigdata_len = mpi_size(&(rsa.N));
1494 sig->sigdata = malloc(sig->sigdata_len);
1495 if (sig->sigdata == NULL) return PDKIM_ERR_OOM;
1496
1497 if (rsa_pkcs1_sign( &rsa, RSA_PRIVATE,
1498 ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1499 SIG_RSA_SHA1:SIG_RSA_SHA256),
1500 0,
1501 (unsigned char *)headerhash,
1502 (unsigned char *)sig->sigdata ) != 0) {
1503 return PDKIM_ERR_RSA_SIGNING;
1504 }
1505
1506 rsa_free(&rsa);
1507
1508 #ifdef PDKIM_DEBUG
1509 if (ctx->debug_stream) {
1510 fprintf(ctx->debug_stream, "PDKIM [%s] b computed: ",
1511 sig->domain);
1512 pdkim_hexprint(ctx->debug_stream, sig->sigdata, sig->sigdata_len, 1);
1513 }
1514 #endif
1515
1516 sig->signature_header = pdkim_create_header(ctx->sig,1);
1517 if (sig->signature_header == NULL) return PDKIM_ERR_OOM;
1518 }
1519 /* VERIFICATION ----------------------------------------------------------- */
1520 else {
1521 rsa_context rsa;
1522 char *dns_txt_name, *dns_txt_reply;
1523
1524 rsa_init(&rsa,RSA_PKCS_V15,0,NULL,NULL);
1525
1526 dns_txt_name = malloc(PDKIM_DNS_TXT_MAX_NAMELEN);
1527 if (dns_txt_name == NULL) return PDKIM_ERR_OOM;
1528 dns_txt_reply = malloc(PDKIM_DNS_TXT_MAX_RECLEN);
1529 if (dns_txt_reply == NULL) {
1530 free(dns_txt_name);
1531 return PDKIM_ERR_OOM;
1532 }
1533 memset(dns_txt_reply,0,PDKIM_DNS_TXT_MAX_RECLEN);
1534 memset(dns_txt_name ,0,PDKIM_DNS_TXT_MAX_NAMELEN);
1535
1536 if (snprintf(dns_txt_name,PDKIM_DNS_TXT_MAX_NAMELEN,
1537 "%s._domainkey.%s.",
1538 sig->selector,sig->domain) >= PDKIM_DNS_TXT_MAX_NAMELEN) {
1539 sig->verify_status = PDKIM_VERIFY_INVALID;
1540 sig->verify_ext_status = PDKIM_VERIFY_INVALID_BUFFER_SIZE;
1541 goto NEXT_VERIFY;
1542 }
1543
1544 if ((ctx->dns_txt_callback(dns_txt_name, dns_txt_reply) != PDKIM_OK) ||
1545 (dns_txt_reply[0] == '\0')) {
1546 sig->verify_status = PDKIM_VERIFY_INVALID;
1547 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
1548 goto NEXT_VERIFY;
1549 }
1550
1551 #ifdef PDKIM_DEBUG
1552 if (ctx->debug_stream) {
1553 fprintf(ctx->debug_stream,
1554 "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1555 fprintf(ctx->debug_stream,"Raw record: ");
1556 pdkim_quoteprint(ctx->debug_stream, dns_txt_reply, strlen(dns_txt_reply), 1);
1557 }
1558 #endif
1559
1560 sig->pubkey = pdkim_parse_pubkey_record(ctx,dns_txt_reply);
1561 if (sig->pubkey == NULL) {
1562 sig->verify_status = PDKIM_VERIFY_INVALID;
1563 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1564 #ifdef PDKIM_DEBUG
1565 if (ctx->debug_stream) {
1566 fprintf(ctx->debug_stream,"Error while parsing public key record\n");
1567 fprintf(ctx->debug_stream,
1568 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1569 }
1570 #endif
1571 goto NEXT_VERIFY;
1572 }
1573
1574 #ifdef PDKIM_DEBUG
1575 if (ctx->debug_stream) {
1576 fprintf(ctx->debug_stream,
1577 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1578 }
1579 #endif
1580
1581 if (rsa_parse_public_key(&rsa,
1582 (unsigned char *)sig->pubkey->key,
1583 sig->pubkey->key_len) != 0) {
1584 sig->verify_status = PDKIM_VERIFY_INVALID;
1585 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1586 goto NEXT_VERIFY;
1587 }
1588
1589 /* Check the signature */
1590 if (rsa_pkcs1_verify(&rsa,
1591 RSA_PUBLIC,
1592 ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1593 SIG_RSA_SHA1:SIG_RSA_SHA256),
1594 0,
1595 (unsigned char *)headerhash,
1596 (unsigned char *)sig->sigdata) != 0) {
1597 sig->verify_status = PDKIM_VERIFY_FAIL;
1598 sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE;
1599 goto NEXT_VERIFY;
1600 }
1601
1602 /* We have a winner! (if bodydhash was correct earlier) */
1603 if (sig->verify_status == PDKIM_VERIFY_NONE) {
1604 sig->verify_status = PDKIM_VERIFY_PASS;
1605 }
1606
1607 NEXT_VERIFY:
1608
1609 #ifdef PDKIM_DEBUG
1610 if (ctx->debug_stream) {
1611 fprintf(ctx->debug_stream, "PDKIM [%s] signature status: %s",
1612 sig->domain, pdkim_verify_status_str(sig->verify_status));
1613 if (sig->verify_ext_status > 0) {
1614 fprintf(ctx->debug_stream, " (%s)\n",
1615 pdkim_verify_ext_status_str(sig->verify_ext_status));
1616 }
1617 else {
1618 fprintf(ctx->debug_stream, "\n");
1619 }
1620 }
1621 #endif
1622
1623 rsa_free(&rsa);
1624 free(dns_txt_name);
1625 free(dns_txt_reply);
1626 }
1627
1628 sig = sig->next;
1629 }
1630
1631 /* If requested, set return pointer to signature(s) */
1632 if (return_signatures != NULL) {
1633 *return_signatures = ctx->sig;
1634 }
1635
1636 return PDKIM_OK;
1637 }
1638
1639
1640 /* -------------------------------------------------------------------------- */
1641 DLLEXPORT pdkim_ctx *pdkim_init_verify(int input_mode,
1642 int(*dns_txt_callback)(char *, char *)
1643 ) {
1644 pdkim_ctx *ctx = malloc(sizeof(pdkim_ctx));
1645 if (ctx == NULL) return NULL;
1646 memset(ctx,0,sizeof(pdkim_ctx));
1647
1648 ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN);
1649 if (ctx->linebuf == NULL) {
1650 free(ctx);
1651 return NULL;
1652 }
1653
1654 ctx->mode = PDKIM_MODE_VERIFY;
1655 ctx->input_mode = input_mode;
1656 ctx->dns_txt_callback = dns_txt_callback;
1657
1658 return ctx;
1659 }
1660
1661
1662 /* -------------------------------------------------------------------------- */
1663 DLLEXPORT pdkim_ctx *pdkim_init_sign(int input_mode,
1664 char *domain,
1665 char *selector,
1666 char *rsa_privkey) {
1667 pdkim_ctx *ctx;
1668 pdkim_signature *sig;
1669
1670 if (!domain || !selector || !rsa_privkey) return NULL;
1671
1672 ctx = malloc(sizeof(pdkim_ctx));
1673 if (ctx == NULL) return NULL;
1674 memset(ctx,0,sizeof(pdkim_ctx));
1675
1676 ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN);
1677 if (ctx->linebuf == NULL) {
1678 free(ctx);
1679 return NULL;
1680 }
1681
1682 sig = malloc(sizeof(pdkim_signature));
1683 if (sig == NULL) {
1684 free(ctx->linebuf);
1685 free(ctx);
1686 return NULL;
1687 }
1688 memset(sig,0,sizeof(pdkim_signature));
1689 sig->bodylength = -1;
1690
1691 ctx->mode = PDKIM_MODE_SIGN;
1692 ctx->input_mode = input_mode;
1693 ctx->sig = sig;
1694
1695 ctx->sig->domain = strdup(domain);
1696 ctx->sig->selector = strdup(selector);
1697 ctx->sig->rsa_privkey = strdup(rsa_privkey);
1698
1699 if (!ctx->sig->domain || !ctx->sig->selector || !ctx->sig->rsa_privkey) {
1700 pdkim_free_ctx(ctx);
1701 return NULL;
1702 }
1703
1704 ctx->sig->sha1_body = malloc(sizeof(sha1_context));
1705 if (ctx->sig->sha1_body == NULL) {
1706 pdkim_free_ctx(ctx);
1707 return NULL;
1708 }
1709 sha1_starts(ctx->sig->sha1_body);
1710
1711 ctx->sig->sha2_body = malloc(sizeof(sha2_context));
1712 if (ctx->sig->sha2_body == NULL) {
1713 pdkim_free_ctx(ctx);
1714 return NULL;
1715 }
1716 sha2_starts(ctx->sig->sha2_body,0);
1717
1718 return ctx;
1719 }
1720
1721 #ifdef PDKIM_DEBUG
1722 /* -------------------------------------------------------------------------- */
1723 DLLEXPORT void pdkim_set_debug_stream(pdkim_ctx *ctx,
1724 FILE *debug_stream) {
1725 ctx->debug_stream = debug_stream;
1726 }
1727 #endif
1728
1729 /* -------------------------------------------------------------------------- */
1730 DLLEXPORT int pdkim_set_optional(pdkim_ctx *ctx,
1731 char *sign_headers,
1732 char *identity,
1733 int canon_headers,
1734 int canon_body,
1735 long bodylength,
1736 int algo,
1737 unsigned long created,
1738 unsigned long expires) {
1739
1740 if (identity != NULL) {
1741 ctx->sig->identity = strdup(identity);
1742 if (ctx->sig->identity == NULL) return PDKIM_ERR_OOM;
1743 }
1744
1745 if (sign_headers != NULL) {
1746 ctx->sig->sign_headers = strdup(sign_headers);
1747 if (ctx->sig->sign_headers == NULL) return PDKIM_ERR_OOM;
1748 }
1749
1750 ctx->sig->canon_headers = canon_headers;
1751 ctx->sig->canon_body = canon_body;
1752 ctx->sig->bodylength = bodylength;
1753 ctx->sig->algo = algo;
1754 ctx->sig->created = created;
1755 ctx->sig->expires = expires;
1756
1757 return PDKIM_OK;
1758 }