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