fa5d88d599927fd11a41f78b90587c94ae804475
[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 *q = '\0';
424 if (crlf) strcat(relaxed,"\r\n");
425 return relaxed;
426 }
427
428
429 /* -------------------------------------------------------------------------- */
430 #define PDKIM_QP_ERROR_DECODE -1
431 char *pdkim_decode_qp_char(char *qp_p, int *c) {
432 char *initial_pos = qp_p;
433
434 /* Advance one char */
435 qp_p++;
436
437 /* Check for two hex digits and decode them */
438 if (isxdigit(*qp_p) && isxdigit(qp_p[1])) {
439 /* Do hex conversion */
440 if (isdigit(*qp_p)) {*c = *qp_p - '0';}
441 else {*c = toupper(*qp_p) - 'A' + 10;}
442 *c <<= 4;
443 if (isdigit(qp_p[1])) {*c |= qp_p[1] - '0';}
444 else {*c |= toupper(qp_p[1]) - 'A' + 10;}
445 return qp_p + 2;
446 }
447
448 /* Illegal char here */
449 *c = PDKIM_QP_ERROR_DECODE;
450 return initial_pos;
451 }
452
453
454 /* -------------------------------------------------------------------------- */
455 char *pdkim_decode_qp(char *str) {
456 int nchar = 0;
457 char *q;
458 char *p = str;
459 char *n = malloc(strlen(p)+1);
460 if (n == NULL) return NULL;
461 *n = '\0';
462 q = n;
463 while (*p != '\0') {
464 if (*p == '=') {
465 p = pdkim_decode_qp_char(p,&nchar);
466 if (nchar >= 0) {
467 *q = nchar;
468 q++;
469 continue;
470 }
471 }
472 else {
473 *q = *p;
474 q++;
475 }
476 p++;
477 }
478 *q = '\0';
479 return n;
480 }
481
482
483 /* -------------------------------------------------------------------------- */
484 char *pdkim_decode_base64(char *str, int *num_decoded) {
485 int dlen = 0;
486 char *res;
487
488 base64_decode(NULL, &dlen, (unsigned char *)str, strlen(str));
489 res = malloc(dlen+1);
490 if (res == NULL) return NULL;
491 if (base64_decode((unsigned char *)res,&dlen,(unsigned char *)str,strlen(str)) != 0) {
492 free(res);
493 return NULL;
494 }
495 if (num_decoded != NULL) *num_decoded = dlen;
496 return res;
497 }
498
499 /* -------------------------------------------------------------------------- */
500 char *pdkim_encode_base64(char *str, int num) {
501 int dlen = 0;
502 char *res;
503
504 base64_encode(NULL, &dlen, (unsigned char *)str, num);
505 res = malloc(dlen+1);
506 if (res == NULL) return NULL;
507 if (base64_encode((unsigned char *)res,&dlen,(unsigned char *)str,num) != 0) {
508 free(res);
509 return NULL;
510 }
511 return res;
512 }
513
514
515 /* -------------------------------------------------------------------------- */
516 #define PDKIM_HDR_LIMBO 0
517 #define PDKIM_HDR_TAG 1
518 #define PDKIM_HDR_VALUE 2
519 pdkim_signature *pdkim_parse_sig_header(pdkim_ctx *ctx, char *raw_hdr) {
520 pdkim_signature *sig ;
521 char *p,*q;
522 pdkim_str *cur_tag = NULL;
523 pdkim_str *cur_val = NULL;
524 int past_hname = 0;
525 int in_b_val = 0;
526 int where = PDKIM_HDR_LIMBO;
527 int i;
528
529 sig = malloc(sizeof(pdkim_signature));
530 if (sig == NULL) return NULL;
531 memset(sig,0,sizeof(pdkim_signature));
532 sig->bodylength = -1;
533
534 sig->rawsig_no_b_val = malloc(strlen(raw_hdr)+1);
535 if (sig->rawsig_no_b_val == NULL) {
536 free(sig);
537 return NULL;
538 }
539
540 p = raw_hdr;
541 q = sig->rawsig_no_b_val;
542
543 while (1) {
544
545 /* Ignore FWS */
546 if ( (*p == '\r') || (*p == '\n') )
547 goto NEXT_CHAR;
548
549 /* Fast-forward through header name */
550 if (!past_hname) {
551 if (*p == ':') past_hname = 1;
552 goto NEXT_CHAR;
553 }
554
555 if (where == PDKIM_HDR_LIMBO) {
556 /* In limbo, just wait for a tag-char to appear */
557 if (!((*p >= 'a') && (*p <= 'z')))
558 goto NEXT_CHAR;
559
560 where = PDKIM_HDR_TAG;
561 }
562
563 if (where == PDKIM_HDR_TAG) {
564 if (cur_tag == NULL)
565 cur_tag = pdkim_strnew(NULL);
566
567 if ((*p >= 'a') && (*p <= 'z'))
568 pdkim_strncat(cur_tag,p,1);
569
570 if (*p == '=') {
571 if (strcmp(cur_tag->str,"b") == 0) {
572 *q = '='; q++;
573 in_b_val = 1;
574 }
575 where = PDKIM_HDR_VALUE;
576 goto NEXT_CHAR;
577 }
578 }
579
580 if (where == PDKIM_HDR_VALUE) {
581 if (cur_val == NULL)
582 cur_val = pdkim_strnew(NULL);
583
584 if ( (*p == '\r') || (*p == '\n') || (*p == ' ') || (*p == '\t') )
585 goto NEXT_CHAR;
586
587 if ( (*p == ';') || (*p == '\0') ) {
588 if (cur_tag->len > 0) {
589 pdkim_strtrim(cur_val);
590 #ifdef PDKIM_DEBUG
591 if (ctx->debug_stream)
592 fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str);
593 #endif
594 switch (cur_tag->str[0]) {
595 case 'b':
596 switch (cur_tag->str[1]) {
597 case 'h':
598 sig->bodyhash = pdkim_decode_base64(cur_val->str,&(sig->bodyhash_len));
599 break;
600 default:
601 sig->sigdata = pdkim_decode_base64(cur_val->str,&(sig->sigdata_len));
602 break;
603 }
604 break;
605 case 'v':
606 if (strcmp(cur_val->str,PDKIM_SIGNATURE_VERSION) == 0) {
607 /* We only support version 1, and that is currently the
608 only version there is. */
609 sig->version = 1;
610 }
611 break;
612 case 'a':
613 i = 0;
614 while (pdkim_algos[i] != NULL) {
615 if (strcmp(cur_val->str,pdkim_algos[i]) == 0 ) {
616 sig->algo = i;
617 break;
618 }
619 i++;
620 }
621 break;
622 case 'c':
623 i = 0;
624 while (pdkim_combined_canons[i].str != NULL) {
625 if (strcmp(cur_val->str,pdkim_combined_canons[i].str) == 0 ) {
626 sig->canon_headers = pdkim_combined_canons[i].canon_headers;
627 sig->canon_body = pdkim_combined_canons[i].canon_body;
628 break;
629 }
630 i++;
631 }
632 break;
633 case 'q':
634 i = 0;
635 while (pdkim_querymethods[i] != NULL) {
636 if (strcmp(cur_val->str,pdkim_querymethods[i]) == 0 ) {
637 sig->querymethod = i;
638 break;
639 }
640 i++;
641 }
642 break;
643 case 's':
644 sig->selector = strdup(cur_val->str);
645 break;
646 case 'd':
647 sig->domain = strdup(cur_val->str);
648 break;
649 case 'i':
650 sig->identity = pdkim_decode_qp(cur_val->str);
651 break;
652 case 't':
653 sig->created = strtoul(cur_val->str,NULL,10);
654 break;
655 case 'x':
656 sig->expires = strtoul(cur_val->str,NULL,10);
657 break;
658 case 'l':
659 sig->bodylength = strtol(cur_val->str,NULL,10);
660 break;
661 case 'h':
662 sig->headernames = strdup(cur_val->str);
663 break;
664 case 'z':
665 sig->copiedheaders = pdkim_decode_qp(cur_val->str);
666 break;
667 default:
668 #ifdef PDKIM_DEBUG
669 if (ctx->debug_stream)
670 fprintf(ctx->debug_stream, "Unknown tag encountered\n");
671 #endif
672 break;
673 }
674 }
675 pdkim_strclear(cur_tag);
676 pdkim_strclear(cur_val);
677 in_b_val = 0;
678 where = PDKIM_HDR_LIMBO;
679 goto NEXT_CHAR;
680 }
681 else pdkim_strncat(cur_val,p,1);
682 }
683
684 NEXT_CHAR:
685 if (*p == '\0') break;
686
687 if (!in_b_val) {
688 *q = *p;
689 q++;
690 }
691 p++;
692 }
693
694 /* Make sure the most important bits are there. */
695 if (!(sig->domain && (*(sig->domain) != '\0') &&
696 sig->selector && (*(sig->selector) != '\0') &&
697 sig->headernames && (*(sig->headernames) != '\0') &&
698 sig->bodyhash &&
699 sig->sigdata &&
700 sig->version)) {
701 pdkim_free_sig(sig);
702 return NULL;
703 }
704
705 /* Copy header list to 'tick-off' header list */
706 sig->hnames_check = strdup(sig->headernames);
707
708 *q = '\0';
709 /* Chomp raw header. The final newline must not be added to the signature. */
710 q--;
711 while( (q > sig->rawsig_no_b_val) && ((*q == '\r') || (*q == '\n')) ) {
712 *q = '\0'; q--;
713 }
714
715 #ifdef PDKIM_DEBUG
716 if (ctx->debug_stream) {
717 fprintf(ctx->debug_stream,
718 "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
719 pdkim_quoteprint(ctx->debug_stream,
720 sig->rawsig_no_b_val,
721 strlen(sig->rawsig_no_b_val), 1);
722 fprintf(ctx->debug_stream,
723 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
724 }
725 #endif
726
727 sig->sha1_body = malloc(sizeof(sha1_context));
728 if (sig->sha1_body == NULL) {
729 pdkim_free_sig(sig);
730 return NULL;
731 }
732 sig->sha2_body = malloc(sizeof(sha2_context));
733 if (sig->sha2_body == NULL) {
734 pdkim_free_sig(sig);
735 return NULL;
736 }
737
738 sha1_starts(sig->sha1_body);
739 sha2_starts(sig->sha2_body,0);
740
741 return sig;
742 }
743
744
745 /* -------------------------------------------------------------------------- */
746 pdkim_pubkey *pdkim_parse_pubkey_record(pdkim_ctx *ctx, char *raw_record) {
747 pdkim_pubkey *pub ;
748 char *p;
749 pdkim_str *cur_tag = NULL;
750 pdkim_str *cur_val = NULL;
751 int where = PDKIM_HDR_LIMBO;
752
753 pub = malloc(sizeof(pdkim_pubkey));
754 if (pub == NULL) return NULL;
755 memset(pub,0,sizeof(pdkim_pubkey));
756
757 p = raw_record;
758
759 while (1) {
760
761 /* Ignore FWS */
762 if ( (*p == '\r') || (*p == '\n') )
763 goto NEXT_CHAR;
764
765 if (where == PDKIM_HDR_LIMBO) {
766 /* In limbo, just wait for a tag-char to appear */
767 if (!((*p >= 'a') && (*p <= 'z')))
768 goto NEXT_CHAR;
769
770 where = PDKIM_HDR_TAG;
771 }
772
773 if (where == PDKIM_HDR_TAG) {
774 if (cur_tag == NULL)
775 cur_tag = pdkim_strnew(NULL);
776
777 if ((*p >= 'a') && (*p <= 'z'))
778 pdkim_strncat(cur_tag,p,1);
779
780 if (*p == '=') {
781 where = PDKIM_HDR_VALUE;
782 goto NEXT_CHAR;
783 }
784 }
785
786 if (where == PDKIM_HDR_VALUE) {
787 if (cur_val == NULL)
788 cur_val = pdkim_strnew(NULL);
789
790 if ( (*p == '\r') || (*p == '\n') )
791 goto NEXT_CHAR;
792
793 if ( (*p == ';') || (*p == '\0') ) {
794 if (cur_tag->len > 0) {
795 pdkim_strtrim(cur_val);
796 #ifdef PDKIM_DEBUG
797 if (ctx->debug_stream)
798 fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str);
799 #endif
800 switch (cur_tag->str[0]) {
801 case 'v':
802 /* This tag isn't evaluated because:
803 - We only support version DKIM1.
804 - Which is the default for this value (set below)
805 - Other versions are currently not specified. */
806 break;
807 case 'h':
808 pub->hashes = strdup(cur_val->str);
809 break;
810 case 'g':
811 pub->granularity = strdup(cur_val->str);
812 break;
813 case 'n':
814 pub->notes = pdkim_decode_qp(cur_val->str);
815 break;
816 case 'p':
817 pub->key = pdkim_decode_base64(cur_val->str,&(pub->key_len));
818 break;
819 case 'k':
820 pub->hashes = strdup(cur_val->str);
821 break;
822 case 's':
823 pub->srvtype = strdup(cur_val->str);
824 break;
825 case 't':
826 if (strchr(cur_val->str,'y') != NULL) pub->testing = 1;
827 if (strchr(cur_val->str,'s') != NULL) pub->no_subdomaining = 1;
828 break;
829 default:
830 #ifdef PDKIM_DEBUG
831 if (ctx->debug_stream)
832 fprintf(ctx->debug_stream, "Unknown tag encountered\n");
833 #endif
834 break;
835 }
836 }
837 pdkim_strclear(cur_tag);
838 pdkim_strclear(cur_val);
839 where = PDKIM_HDR_LIMBO;
840 goto NEXT_CHAR;
841 }
842 else pdkim_strncat(cur_val,p,1);
843 }
844
845 NEXT_CHAR:
846 if (*p == '\0') break;
847 p++;
848 }
849
850 /* Set fallback defaults */
851 if (pub->version == NULL) pub->version = strdup(PDKIM_PUB_RECORD_VERSION);
852 if (pub->granularity == NULL) pub->granularity = strdup("*");
853 if (pub->keytype == NULL) pub->keytype = strdup("rsa");
854 if (pub->srvtype == NULL) pub->srvtype = strdup("*");
855
856 /* p= is required */
857 if (pub->key == NULL) {
858 pdkim_free_pubkey(pub);
859 return NULL;
860 }
861
862 return pub;
863 }
864
865
866 /* -------------------------------------------------------------------------- */
867 int pdkim_update_bodyhash(pdkim_ctx *ctx, char *data, int len) {
868 pdkim_signature *sig = ctx->sig;
869 /* Cache relaxed version of data */
870 char *relaxed_data = NULL;
871 int relaxed_len = 0;
872
873 /* Traverse all signatures, updating their hashes. */
874 while (sig != NULL) {
875 /* Defaults to simple canon (no further treatment necessary) */
876 char *canon_data = data;
877 int canon_len = len;
878
879 if (sig->canon_body == PDKIM_CANON_RELAXED) {
880 /* Relax the line if not done already */
881 if (relaxed_data == NULL) {
882 int seen_wsp = 0;
883 char *p = data;
884 int q = 0;
885 relaxed_data = malloc(len+1);
886 if (relaxed_data == NULL) return PDKIM_ERR_OOM;
887 while (*p != '\0') {
888 char c = *p;
889 if (c == '\r') {
890 if ( (q > 0) && (relaxed_data[q-1] == ' ') ) q--;
891 }
892 else if ( (c == '\t') || (c == ' ') ) {
893 c = ' '; /* Turns WSP into SP */
894 if (seen_wsp) {
895 p++;
896 continue;
897 }
898 else seen_wsp = 1;
899 }
900 else seen_wsp = 0;
901 relaxed_data[q++] = c;
902 p++;
903 }
904 relaxed_data[q] = '\0';
905 relaxed_len = q;
906 }
907 canon_data = relaxed_data;
908 canon_len = relaxed_len;
909 }
910
911 /* Make sure we don't exceed the to-be-signed body length */
912 if ((sig->bodylength >= 0) &&
913 ((sig->signed_body_bytes+(unsigned long)canon_len) > sig->bodylength))
914 canon_len = (sig->bodylength - sig->signed_body_bytes);
915
916 if (canon_len > 0) {
917 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
918 sha1_update(sig->sha1_body,(unsigned char *)canon_data,canon_len);
919 else
920 sha2_update(sig->sha2_body,(unsigned char *)canon_data,canon_len);
921 sig->signed_body_bytes += canon_len;
922 #ifdef PDKIM_DEBUG
923 if (ctx->debug_stream!=NULL)
924 pdkim_quoteprint(ctx->debug_stream,canon_data,canon_len,0);
925 #endif
926 }
927
928 sig = sig->next;
929 }
930
931 if (relaxed_data != NULL) free(relaxed_data);
932 return PDKIM_OK;
933 }
934
935
936 /* -------------------------------------------------------------------------- */
937 int pdkim_finish_bodyhash(pdkim_ctx *ctx) {
938 pdkim_signature *sig = ctx->sig;
939
940 /* Traverse all signatures */
941 while (sig != NULL) {
942
943 /* Finish hashes */
944 unsigned char bh[32]; /* SHA-256 = 32 Bytes, SHA-1 = 20 Bytes */
945 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
946 sha1_finish(sig->sha1_body,bh);
947 else
948 sha2_finish(sig->sha2_body,bh);
949
950 #ifdef PDKIM_DEBUG
951 if (ctx->debug_stream) {
952 fprintf(ctx->debug_stream, "PDKIM [%s] Body bytes hashed: %lu\n",
953 sig->domain, sig->signed_body_bytes);
954 fprintf(ctx->debug_stream, "PDKIM [%s] bh computed: ", sig->domain);
955 pdkim_hexprint(ctx->debug_stream, (char *)bh,
956 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1);
957 }
958 #endif
959
960 /* SIGNING -------------------------------------------------------------- */
961 if (ctx->mode == PDKIM_MODE_SIGN) {
962 sig->bodyhash_len = (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32;
963 sig->bodyhash = malloc(sig->bodyhash_len);
964 if (sig->bodyhash == NULL) return PDKIM_ERR_OOM;
965 memcpy(sig->bodyhash,bh,sig->bodyhash_len);
966
967 /* If bodylength limit is set, and we have received less bytes
968 than the requested amount, effectively remove the limit tag. */
969 if (sig->signed_body_bytes < sig->bodylength) sig->bodylength = -1;
970 }
971 /* VERIFICATION --------------------------------------------------------- */
972 else {
973 /* Compare bodyhash */
974 if (memcmp(bh,sig->bodyhash,
975 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32) == 0) {
976 #ifdef PDKIM_DEBUG
977 if (ctx->debug_stream)
978 fprintf(ctx->debug_stream, "PDKIM [%s] Body hash verified OK\n",
979 sig->domain);
980 #endif
981 }
982 else {
983 #ifdef PDKIM_DEBUG
984 if (ctx->debug_stream) {
985 fprintf(ctx->debug_stream, "PDKIM [%s] Body hash did NOT verify\n",
986 sig->domain);
987 fprintf(ctx->debug_stream, "PDKIM [%s] bh signature: ", sig->domain);
988 pdkim_hexprint(ctx->debug_stream, sig->bodyhash,
989 (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1);
990 }
991 #endif
992 sig->verify_status = PDKIM_VERIFY_FAIL;
993 sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY;
994 }
995 }
996
997 sig = sig->next;
998 }
999
1000 return PDKIM_OK;
1001 }
1002
1003
1004
1005 /* -------------------------------------------------------------------------- */
1006 /* Callback from pdkim_feed below for processing complete body lines */
1007 int pdkim_bodyline_complete(pdkim_ctx *ctx) {
1008 char *p = ctx->linebuf;
1009 int n = ctx->linebuf_offset;
1010
1011 /* Ignore extra data if we've seen the end-of-data marker */
1012 if (ctx->seen_eod) goto BAIL;
1013
1014 /* We've always got one extra byte to stuff a zero ... */
1015 ctx->linebuf[(ctx->linebuf_offset)] = '\0';
1016
1017 if (ctx->input_mode == PDKIM_INPUT_SMTP) {
1018 /* Terminate on EOD marker */
1019 if (memcmp(p,".\r\n",3) == 0) {
1020 ctx->seen_eod = 1;
1021 goto BAIL;
1022 }
1023 /* Unstuff dots */
1024 if (memcmp(p,"..",2) == 0) {
1025 p++;
1026 n--;
1027 }
1028 }
1029
1030 /* Empty lines need to be buffered until we find a non-empty line */
1031 if (memcmp(p,"\r\n",2) == 0) {
1032 ctx->num_buffered_crlf++;
1033 goto BAIL;
1034 }
1035
1036 /* At this point, we have a non-empty line, so release the buffered ones. */
1037 while (ctx->num_buffered_crlf) {
1038 pdkim_update_bodyhash(ctx,"\r\n",2);
1039 ctx->num_buffered_crlf--;
1040 }
1041
1042 pdkim_update_bodyhash(ctx,p,n);
1043
1044 BAIL:
1045 ctx->linebuf_offset = 0;
1046 return PDKIM_OK;
1047 }
1048
1049
1050 /* -------------------------------------------------------------------------- */
1051 /* Callback from pdkim_feed below for processing complete headers */
1052 #define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:"
1053 int pdkim_header_complete(pdkim_ctx *ctx) {
1054 pdkim_signature *sig = ctx->sig;
1055
1056 /* Special case: The last header can have an extra \r appended */
1057 if ( (ctx->cur_header->len > 1) &&
1058 (ctx->cur_header->str[(ctx->cur_header->len)-1] == '\r') ) {
1059 ctx->cur_header->str[(ctx->cur_header->len)-1] = '\0';
1060 ctx->cur_header->len--;
1061 }
1062
1063 ctx->num_headers++;
1064 if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
1065
1066 /* Traverse all signatures */
1067 while (sig != NULL) {
1068 pdkim_stringlist *list;
1069
1070 /* SIGNING -------------------------------------------------------------- */
1071 if (ctx->mode == PDKIM_MODE_SIGN) {
1072 if (header_name_match(ctx->cur_header->str,
1073 sig->sign_headers?
1074 sig->sign_headers:
1075 PDKIM_DEFAULT_SIGN_HEADERS, 0) != PDKIM_OK) goto NEXT_SIG;
1076 }
1077 /* VERIFICATION --------------------------------------------------------- */
1078 else {
1079 /* Header is not included or all instances were already 'ticked off' */
1080 if (header_name_match(ctx->cur_header->str,
1081 sig->hnames_check, 1) != PDKIM_OK) goto NEXT_SIG;
1082 }
1083
1084 /* Add header to the signed headers list (in reverse order) */
1085 list = pdkim_prepend_stringlist(sig->headers,
1086 ctx->cur_header->str);
1087 if (list == NULL) return PDKIM_ERR_OOM;
1088 sig->headers = list;
1089
1090 NEXT_SIG:
1091 sig = sig->next;
1092 }
1093
1094 /* DKIM-Signature: headers are added to the verification list */
1095 if ( (ctx->mode == PDKIM_MODE_VERIFY) &&
1096 (strncasecmp(ctx->cur_header->str,
1097 DKIM_SIGNATURE_HEADERNAME,
1098 strlen(DKIM_SIGNATURE_HEADERNAME)) == 0) ) {
1099 pdkim_signature *new_sig;
1100 /* Create and chain new signature block */
1101 #ifdef PDKIM_DEBUG
1102 if (ctx->debug_stream)
1103 fprintf(ctx->debug_stream,
1104 "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1105 #endif
1106 new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header->str);
1107 if (new_sig != NULL) {
1108 pdkim_signature *last_sig = ctx->sig;
1109 if (last_sig == NULL) {
1110 ctx->sig = new_sig;
1111 }
1112 else {
1113 while (last_sig->next != NULL) { last_sig = last_sig->next; }
1114 last_sig->next = new_sig;
1115 }
1116 }
1117 else {
1118 #ifdef PDKIM_DEBUG
1119 if (ctx->debug_stream) {
1120 fprintf(ctx->debug_stream,"Error while parsing signature header\n");
1121 fprintf(ctx->debug_stream,
1122 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1123 }
1124 #endif
1125 }
1126 }
1127
1128 BAIL:
1129 pdkim_strclear(ctx->cur_header); /* Re-use existing pdkim_str */
1130 return PDKIM_OK;
1131 }
1132
1133
1134
1135 /* -------------------------------------------------------------------------- */
1136 #define HEADER_BUFFER_FRAG_SIZE 256
1137 DLLEXPORT int pdkim_feed (pdkim_ctx *ctx,
1138 char *data,
1139 int len) {
1140 int p;
1141 for (p=0;p<len;p++) {
1142 char c = data[p];
1143 if (ctx->past_headers) {
1144 /* Processing body byte */
1145 ctx->linebuf[(ctx->linebuf_offset)++] = c;
1146 if (c == '\n') {
1147 int rc = pdkim_bodyline_complete(ctx); /* End of line */
1148 if (rc != PDKIM_OK) return rc;
1149 }
1150 if (ctx->linebuf_offset == (PDKIM_MAX_BODY_LINE_LEN-1))
1151 return PDKIM_ERR_LONG_LINE;
1152 }
1153 else {
1154 /* Processing header byte */
1155 if (c != '\r') {
1156 if (c == '\n') {
1157 if (ctx->seen_lf) {
1158 int rc = pdkim_header_complete(ctx); /* Seen last header line */
1159 if (rc != PDKIM_OK) return rc;
1160 ctx->past_headers = 1;
1161 ctx->seen_lf = 0;
1162 #ifdef PDKIM_DEBUG
1163 if (ctx->debug_stream)
1164 fprintf(ctx->debug_stream,
1165 "PDKIM >> Hashed body data, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1166 #endif
1167 continue;
1168 }
1169 else ctx->seen_lf = 1;
1170 }
1171 else if (ctx->seen_lf) {
1172 if (! ((c == '\t') || (c == ' '))) {
1173 int rc = pdkim_header_complete(ctx); /* End of header */
1174 if (rc != PDKIM_OK) return rc;
1175 }
1176 ctx->seen_lf = 0;
1177 }
1178 }
1179 if (ctx->cur_header == NULL) {
1180 ctx->cur_header = pdkim_strnew(NULL);
1181 if (ctx->cur_header == NULL) return PDKIM_ERR_OOM;
1182 }
1183 if (ctx->cur_header->len < PDKIM_MAX_HEADER_LEN)
1184 if (pdkim_strncat(ctx->cur_header,&data[p],1) == NULL)
1185 return PDKIM_ERR_OOM;
1186 }
1187 }
1188 return PDKIM_OK;
1189 }
1190
1191
1192 /* -------------------------------------------------------------------------- */
1193 char *pdkim_create_header(pdkim_signature *sig, int final) {
1194 char *rc = NULL;
1195 char *base64_bh = NULL;
1196 char *base64_b = NULL;
1197 pdkim_str *hdr = pdkim_strnew("DKIM-Signature: v="PDKIM_SIGNATURE_VERSION);
1198 if (hdr == NULL) return NULL;
1199
1200 base64_bh = pdkim_encode_base64(sig->bodyhash, sig->bodyhash_len);
1201 if (base64_bh == NULL) goto BAIL;
1202
1203 /* Required and static bits */
1204 if (
1205 pdkim_strcat(hdr,"; a=") &&
1206 pdkim_strcat(hdr,pdkim_algos[sig->algo]) &&
1207 pdkim_strcat(hdr,"; q=") &&
1208 pdkim_strcat(hdr,pdkim_querymethods[sig->querymethod]) &&
1209 pdkim_strcat(hdr,"; c=") &&
1210 pdkim_strcat(hdr,pdkim_canons[sig->canon_headers]) &&
1211 pdkim_strcat(hdr,"/") &&
1212 pdkim_strcat(hdr,pdkim_canons[sig->canon_body]) &&
1213 pdkim_strcat(hdr,"; d=") &&
1214 pdkim_strcat(hdr,sig->domain) &&
1215 pdkim_strcat(hdr,"; s=") &&
1216 pdkim_strcat(hdr,sig->selector) &&
1217 pdkim_strcat(hdr,";\r\n\th=") &&
1218 pdkim_strcat(hdr,sig->headernames) &&
1219 pdkim_strcat(hdr,"; bh=") &&
1220 pdkim_strcat(hdr,base64_bh) &&
1221 pdkim_strcat(hdr,";\r\n\t")
1222 ) {
1223 /* Optional bits */
1224 if (sig->identity != NULL) {
1225 if (!( pdkim_strcat(hdr,"i=") &&
1226 pdkim_strcat(hdr,sig->identity) &&
1227 pdkim_strcat(hdr,";") ) ) {
1228 goto BAIL;
1229 }
1230 }
1231 if (sig->created > 0) {
1232 if (!( pdkim_strcat(hdr,"t=") &&
1233 pdkim_numcat(hdr,sig->created) &&
1234 pdkim_strcat(hdr,";") ) ) {
1235 goto BAIL;
1236 }
1237 }
1238 if (sig->expires > 0) {
1239 if (!( pdkim_strcat(hdr,"x=") &&
1240 pdkim_numcat(hdr,sig->expires) &&
1241 pdkim_strcat(hdr,";") ) ) {
1242 goto BAIL;
1243 }
1244 }
1245 if (sig->bodylength >= 0) {
1246 if (!( pdkim_strcat(hdr,"l=") &&
1247 pdkim_numcat(hdr,sig->bodylength) &&
1248 pdkim_strcat(hdr,";") ) ) {
1249 goto BAIL;
1250 }
1251 }
1252 /* Extra linebreak */
1253 if (hdr->str[(hdr->len)-1] == ';') {
1254 if (!pdkim_strcat(hdr," \r\n\t")) goto BAIL;
1255 }
1256 /* Preliminary or final version? */
1257 if (final) {
1258 base64_b = pdkim_encode_base64(sig->sigdata, sig->sigdata_len);
1259 if (base64_b == NULL) goto BAIL;
1260 if (
1261 pdkim_strcat(hdr,"b=") &&
1262 pdkim_strcat(hdr,base64_b) &&
1263 pdkim_strcat(hdr,";")
1264 ) goto DONE;
1265 }
1266 else {
1267 if (pdkim_strcat(hdr,"b=;")) goto DONE;
1268 }
1269
1270 goto BAIL;
1271 }
1272
1273 DONE:
1274 rc = strdup(hdr->str);
1275
1276 BAIL:
1277 pdkim_strfree(hdr);
1278 if (base64_bh != NULL) free(base64_bh);
1279 if (base64_b != NULL) free(base64_b);
1280 return rc;
1281 }
1282
1283
1284 /* -------------------------------------------------------------------------- */
1285 DLLEXPORT int pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures) {
1286 pdkim_signature *sig = ctx->sig;
1287 pdkim_str *headernames = NULL; /* Collected signed header names */
1288
1289 /* Check if we must still flush a (partial) header. If that is the
1290 case, the message has no body, and we must compute a body hash
1291 out of '<CR><LF>' */
1292 if (ctx->cur_header && ctx->cur_header->len) {
1293 int rc = pdkim_header_complete(ctx);
1294 if (rc != PDKIM_OK) return rc;
1295 pdkim_update_bodyhash(ctx,"\r\n",2);
1296 }
1297 else {
1298 /* For non-smtp input, check if there's an unfinished line in the
1299 body line buffer. If that is the case, we must add a CRLF to the
1300 hash to properly terminate the message. */
1301 if ((ctx->input_mode == PDKIM_INPUT_NORMAL) && ctx->linebuf_offset) {
1302 pdkim_update_bodyhash(ctx, ctx->linebuf, ctx->linebuf_offset);
1303 pdkim_update_bodyhash(ctx,"\r\n",2);
1304 }
1305 #ifdef PDKIM_DEBUG
1306 if (ctx->debug_stream)
1307 fprintf(ctx->debug_stream,
1308 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1309 #endif
1310 }
1311
1312 /* Build (and/or evaluate) body hash */
1313 if (pdkim_finish_bodyhash(ctx) != PDKIM_OK) return PDKIM_ERR_OOM;
1314
1315 /* SIGNING -------------------------------------------------------------- */
1316 if (ctx->mode == PDKIM_MODE_SIGN) {
1317 headernames = pdkim_strnew(NULL);
1318 if (headernames == NULL) return PDKIM_ERR_OOM;
1319 }
1320 /* ---------------------------------------------------------------------- */
1321
1322 while (sig != NULL) {
1323 sha1_context sha1_headers;
1324 sha2_context sha2_headers;
1325 char *sig_hdr;
1326 char headerhash[32];
1327
1328 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1329 sha1_starts(&sha1_headers);
1330 else
1331 sha2_starts(&sha2_headers,0);
1332
1333 #ifdef PDKIM_DEBUG
1334 if (ctx->debug_stream)
1335 fprintf(ctx->debug_stream,
1336 "PDKIM >> Hashed header data, canonicalized, in sequence >>>>>>>>>>>>>>\n");
1337 #endif
1338
1339 /* SIGNING ---------------------------------------------------------------- */
1340 /* When signing, walk through our header list and add them to the hash. As we
1341 go, construct a list of the header's names to use for the h= parameter. */
1342 if (ctx->mode == PDKIM_MODE_SIGN) {
1343 pdkim_stringlist *p = sig->headers;
1344 while (p != NULL) {
1345 char *rh = NULL;
1346 /* Collect header names (Note: colon presence is guaranteed here) */
1347 char *q = strchr(p->value,':');
1348 if (pdkim_strncat(headernames, p->value,
1349 (q-(p->value))+((p->next==NULL)?0:1)) == NULL)
1350 return PDKIM_ERR_OOM;
1351
1352 if (sig->canon_headers == PDKIM_CANON_RELAXED)
1353 rh = pdkim_relax_header(p->value,1); /* cook header for relaxed canon */
1354 else
1355 rh = strdup(p->value); /* just copy it for simple canon */
1356
1357 if (rh == NULL) return PDKIM_ERR_OOM;
1358
1359 /* Feed header to the hash algorithm */
1360 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1361 sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh));
1362 else
1363 sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh));
1364 #ifdef PDKIM_DEBUG
1365 if (ctx->debug_stream)
1366 pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1);
1367 #endif
1368 free(rh);
1369 p = p->next;
1370 }
1371 }
1372 /* VERIFICATION ----------------------------------------------------------- */
1373 /* When verifying, walk through the header name list in the h= parameter and
1374 add the headers to the hash in that order. */
1375 else {
1376 char *b = strdup(sig->headernames);
1377 char *p = b;
1378 char *q = NULL;
1379 if (b == NULL) return PDKIM_ERR_OOM;
1380
1381 while(1) {
1382 pdkim_stringlist *hdrs = sig->headers;
1383 q = strchr(p,':');
1384 if (q != NULL) *q = '\0';
1385 while (hdrs != NULL) {
1386 if ( (strncasecmp(hdrs->value,p,strlen(p)) == 0) &&
1387 ((hdrs->value)[strlen(p)] == ':') ) {
1388 char *rh = NULL;
1389 if (sig->canon_headers == PDKIM_CANON_RELAXED)
1390 rh = pdkim_relax_header(hdrs->value,1); /* cook header for relaxed canon */
1391 else
1392 rh = strdup(hdrs->value); /* just copy it for simple canon */
1393 if (rh == NULL) return PDKIM_ERR_OOM;
1394 /* Feed header to the hash algorithm */
1395 if (sig->algo == PDKIM_ALGO_RSA_SHA1)
1396 sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh));
1397 else
1398 sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh));
1399 #ifdef PDKIM_DEBUG
1400 if (ctx->debug_stream)
1401 pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1);
1402 #endif
1403 free(rh);
1404 (hdrs->value)[0] = '_';
1405 break;
1406 }
1407 hdrs = hdrs->next;
1408 }
1409 if (q == NULL) break;
1410 p = q+1;
1411 }
1412 free(b);
1413 }
1414
1415 #ifdef PDKIM_DEBUG
1416 if (ctx->debug_stream)
1417 fprintf(ctx->debug_stream,
1418 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1419 #endif
1420
1421 /* SIGNING ---------------------------------------------------------------- */
1422 if (ctx->mode == PDKIM_MODE_SIGN) {
1423 /* Copy headernames to signature struct */
1424 sig->headernames = strdup(headernames->str);
1425 pdkim_strfree(headernames);
1426
1427 /* Create signature header with b= omitted */
1428 sig_hdr = pdkim_create_header(ctx->sig,0);
1429 }
1430 /* VERIFICATION ----------------------------------------------------------- */
1431 else {
1432 sig_hdr = strdup(sig->rawsig_no_b_val);
1433 }
1434 /* ------------------------------------------------------------------------ */
1435
1436 if (sig_hdr == NULL) return PDKIM_ERR_OOM;
1437
1438 /* Relax header if necessary */
1439 if (sig->canon_headers == PDKIM_CANON_RELAXED) {
1440 char *relaxed_hdr = pdkim_relax_header(sig_hdr,0);
1441 free(sig_hdr);
1442 if (relaxed_hdr == NULL) return PDKIM_ERR_OOM;
1443 sig_hdr = relaxed_hdr;
1444 }
1445
1446 #ifdef PDKIM_DEBUG
1447 if (ctx->debug_stream) {
1448 fprintf(ctx->debug_stream,
1449 "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
1450 pdkim_quoteprint(ctx->debug_stream, sig_hdr, strlen(sig_hdr), 1);
1451 fprintf(ctx->debug_stream,
1452 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1453 }
1454 #endif
1455
1456 /* Finalize header hash */
1457 if (sig->algo == PDKIM_ALGO_RSA_SHA1) {
1458 sha1_update(&(sha1_headers),(unsigned char *)sig_hdr,strlen(sig_hdr));
1459 sha1_finish(&(sha1_headers),(unsigned char *)headerhash);
1460 #ifdef PDKIM_DEBUG
1461 if (ctx->debug_stream) {
1462 fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain);
1463 pdkim_hexprint(ctx->debug_stream, headerhash, 20, 1);
1464 }
1465 #endif
1466 }
1467 else {
1468 sha2_update(&(sha2_headers),(unsigned char *)sig_hdr,strlen(sig_hdr));
1469 sha2_finish(&(sha2_headers),(unsigned char *)headerhash);
1470 #ifdef PDKIM_DEBUG
1471 if (ctx->debug_stream) {
1472 fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain);
1473 pdkim_hexprint(ctx->debug_stream, headerhash, 32, 1);
1474 }
1475 #endif
1476 }
1477
1478 free(sig_hdr);
1479
1480 /* SIGNING ---------------------------------------------------------------- */
1481 if (ctx->mode == PDKIM_MODE_SIGN) {
1482 rsa_context rsa;
1483
1484 rsa_init(&rsa,RSA_PKCS_V15,0,NULL,NULL);
1485
1486 /* Perform private key operation */
1487 if (rsa_parse_key(&rsa, (unsigned char *)sig->rsa_privkey,
1488 strlen(sig->rsa_privkey), NULL, 0) != 0) {
1489 return PDKIM_ERR_RSA_PRIVKEY;
1490 }
1491
1492 sig->sigdata_len = mpi_size(&(rsa.N));
1493 sig->sigdata = malloc(sig->sigdata_len);
1494 if (sig->sigdata == NULL) return PDKIM_ERR_OOM;
1495
1496 if (rsa_pkcs1_sign( &rsa, RSA_PRIVATE,
1497 ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1498 SIG_RSA_SHA1:SIG_RSA_SHA256),
1499 0,
1500 (unsigned char *)headerhash,
1501 (unsigned char *)sig->sigdata ) != 0) {
1502 return PDKIM_ERR_RSA_SIGNING;
1503 }
1504
1505 rsa_free(&rsa);
1506
1507 #ifdef PDKIM_DEBUG
1508 if (ctx->debug_stream) {
1509 fprintf(ctx->debug_stream, "PDKIM [%s] b computed: ",
1510 sig->domain);
1511 pdkim_hexprint(ctx->debug_stream, sig->sigdata, sig->sigdata_len, 1);
1512 }
1513 #endif
1514
1515 sig->signature_header = pdkim_create_header(ctx->sig,1);
1516 if (sig->signature_header == NULL) return PDKIM_ERR_OOM;
1517 }
1518 /* VERIFICATION ----------------------------------------------------------- */
1519 else {
1520 rsa_context rsa;
1521 char *dns_txt_name, *dns_txt_reply;
1522
1523 rsa_init(&rsa,RSA_PKCS_V15,0,NULL,NULL);
1524
1525 dns_txt_name = malloc(PDKIM_DNS_TXT_MAX_NAMELEN);
1526 if (dns_txt_name == NULL) return PDKIM_ERR_OOM;
1527 dns_txt_reply = malloc(PDKIM_DNS_TXT_MAX_RECLEN);
1528 if (dns_txt_reply == NULL) {
1529 free(dns_txt_name);
1530 return PDKIM_ERR_OOM;
1531 }
1532 memset(dns_txt_reply,0,PDKIM_DNS_TXT_MAX_RECLEN);
1533 memset(dns_txt_name ,0,PDKIM_DNS_TXT_MAX_NAMELEN);
1534
1535 if (snprintf(dns_txt_name,PDKIM_DNS_TXT_MAX_NAMELEN,
1536 "%s._domainkey.%s.",
1537 sig->selector,sig->domain) >= PDKIM_DNS_TXT_MAX_NAMELEN) {
1538 sig->verify_status = PDKIM_VERIFY_INVALID;
1539 sig->verify_ext_status = PDKIM_VERIFY_INVALID_BUFFER_SIZE;
1540 goto NEXT_VERIFY;
1541 }
1542
1543 if ((ctx->dns_txt_callback(dns_txt_name, dns_txt_reply) != PDKIM_OK) ||
1544 (dns_txt_reply[0] == '\0')) {
1545 sig->verify_status = PDKIM_VERIFY_INVALID;
1546 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
1547 goto NEXT_VERIFY;
1548 }
1549
1550 #ifdef PDKIM_DEBUG
1551 if (ctx->debug_stream) {
1552 fprintf(ctx->debug_stream,
1553 "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1554 fprintf(ctx->debug_stream,"Raw record: ");
1555 pdkim_quoteprint(ctx->debug_stream, dns_txt_reply, strlen(dns_txt_reply), 1);
1556 }
1557 #endif
1558
1559 sig->pubkey = pdkim_parse_pubkey_record(ctx,dns_txt_reply);
1560 if (sig->pubkey == NULL) {
1561 sig->verify_status = PDKIM_VERIFY_INVALID;
1562 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1563 #ifdef PDKIM_DEBUG
1564 if (ctx->debug_stream) {
1565 fprintf(ctx->debug_stream,"Error while parsing public key record\n");
1566 fprintf(ctx->debug_stream,
1567 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1568 }
1569 #endif
1570 goto NEXT_VERIFY;
1571 }
1572
1573 #ifdef PDKIM_DEBUG
1574 if (ctx->debug_stream) {
1575 fprintf(ctx->debug_stream,
1576 "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
1577 }
1578 #endif
1579
1580 if (rsa_parse_public_key(&rsa,
1581 (unsigned char *)sig->pubkey->key,
1582 sig->pubkey->key_len) != 0) {
1583 sig->verify_status = PDKIM_VERIFY_INVALID;
1584 sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
1585 goto NEXT_VERIFY;
1586 }
1587
1588 /* Check the signature */
1589 if (rsa_pkcs1_verify(&rsa,
1590 RSA_PUBLIC,
1591 ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
1592 SIG_RSA_SHA1:SIG_RSA_SHA256),
1593 0,
1594 (unsigned char *)headerhash,
1595 (unsigned char *)sig->sigdata) != 0) {
1596 sig->verify_status = PDKIM_VERIFY_FAIL;
1597 sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE;
1598 goto NEXT_VERIFY;
1599 }
1600
1601 /* We have a winner! (if bodydhash was correct earlier) */
1602 if (sig->verify_status == PDKIM_VERIFY_NONE) {
1603 sig->verify_status = PDKIM_VERIFY_PASS;
1604 }
1605
1606 NEXT_VERIFY:
1607
1608 #ifdef PDKIM_DEBUG
1609 if (ctx->debug_stream) {
1610 fprintf(ctx->debug_stream, "PDKIM [%s] signature status: %s",
1611 sig->domain, pdkim_verify_status_str(sig->verify_status));
1612 if (sig->verify_ext_status > 0) {
1613 fprintf(ctx->debug_stream, " (%s)\n",
1614 pdkim_verify_ext_status_str(sig->verify_ext_status));
1615 }
1616 else {
1617 fprintf(ctx->debug_stream, "\n");
1618 }
1619 }
1620 #endif
1621
1622 rsa_free(&rsa);
1623 free(dns_txt_name);
1624 free(dns_txt_reply);
1625 }
1626
1627 sig = sig->next;
1628 }
1629
1630 /* If requested, set return pointer to signature(s) */
1631 if (return_signatures != NULL) {
1632 *return_signatures = ctx->sig;
1633 }
1634
1635 return PDKIM_OK;
1636 }
1637
1638
1639 /* -------------------------------------------------------------------------- */
1640 DLLEXPORT pdkim_ctx *pdkim_init_verify(int input_mode,
1641 int(*dns_txt_callback)(char *, char *)
1642 ) {
1643 pdkim_ctx *ctx = malloc(sizeof(pdkim_ctx));
1644 if (ctx == NULL) return NULL;
1645 memset(ctx,0,sizeof(pdkim_ctx));
1646
1647 ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN);
1648 if (ctx->linebuf == NULL) {
1649 free(ctx);
1650 return NULL;
1651 }
1652
1653 ctx->mode = PDKIM_MODE_VERIFY;
1654 ctx->input_mode = input_mode;
1655 ctx->dns_txt_callback = dns_txt_callback;
1656
1657 return ctx;
1658 }
1659
1660
1661 /* -------------------------------------------------------------------------- */
1662 DLLEXPORT pdkim_ctx *pdkim_init_sign(int input_mode,
1663 char *domain,
1664 char *selector,
1665 char *rsa_privkey) {
1666 pdkim_ctx *ctx;
1667 pdkim_signature *sig;
1668
1669 if (!domain || !selector || !rsa_privkey) return NULL;
1670
1671 ctx = malloc(sizeof(pdkim_ctx));
1672 if (ctx == NULL) return NULL;
1673 memset(ctx,0,sizeof(pdkim_ctx));
1674
1675 ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN);
1676 if (ctx->linebuf == NULL) {
1677 free(ctx);
1678 return NULL;
1679 }
1680
1681 sig = malloc(sizeof(pdkim_signature));
1682 if (sig == NULL) {
1683 free(ctx->linebuf);
1684 free(ctx);
1685 return NULL;
1686 }
1687 memset(sig,0,sizeof(pdkim_signature));
1688 sig->bodylength = -1;
1689
1690 ctx->mode = PDKIM_MODE_SIGN;
1691 ctx->input_mode = input_mode;
1692 ctx->sig = sig;
1693
1694 ctx->sig->domain = strdup(domain);
1695 ctx->sig->selector = strdup(selector);
1696 ctx->sig->rsa_privkey = strdup(rsa_privkey);
1697
1698 if (!ctx->sig->domain || !ctx->sig->selector || !ctx->sig->rsa_privkey) {
1699 pdkim_free_ctx(ctx);
1700 return NULL;
1701 }
1702
1703 ctx->sig->sha1_body = malloc(sizeof(sha1_context));
1704 if (ctx->sig->sha1_body == NULL) {
1705 pdkim_free_ctx(ctx);
1706 return NULL;
1707 }
1708 sha1_starts(ctx->sig->sha1_body);
1709
1710 ctx->sig->sha2_body = malloc(sizeof(sha2_context));
1711 if (ctx->sig->sha2_body == NULL) {
1712 pdkim_free_ctx(ctx);
1713 return NULL;
1714 }
1715 sha2_starts(ctx->sig->sha2_body,0);
1716
1717 return ctx;
1718 }
1719
1720 #ifdef PDKIM_DEBUG
1721 /* -------------------------------------------------------------------------- */
1722 DLLEXPORT void pdkim_set_debug_stream(pdkim_ctx *ctx,
1723 FILE *debug_stream) {
1724 ctx->debug_stream = debug_stream;
1725 }
1726 #endif
1727
1728 /* -------------------------------------------------------------------------- */
1729 DLLEXPORT int pdkim_set_optional(pdkim_ctx *ctx,
1730 char *sign_headers,
1731 char *identity,
1732 int canon_headers,
1733 int canon_body,
1734 long bodylength,
1735 int algo,
1736 unsigned long created,
1737 unsigned long expires) {
1738
1739 if (identity != NULL) {
1740 ctx->sig->identity = strdup(identity);
1741 if (ctx->sig->identity == NULL) return PDKIM_ERR_OOM;
1742 }
1743
1744 if (sign_headers != NULL) {
1745 ctx->sig->sign_headers = strdup(sign_headers);
1746 if (ctx->sig->sign_headers == NULL) return PDKIM_ERR_OOM;
1747 }
1748
1749 ctx->sig->canon_headers = canon_headers;
1750 ctx->sig->canon_body = canon_body;
1751 ctx->sig->bodylength = bodylength;
1752 ctx->sig->algo = algo;
1753 ctx->sig->created = created;
1754 ctx->sig->expires = expires;
1755
1756 return PDKIM_OK;
1757 }