Commit | Line | Data |
---|---|---|
80a47a2c TK |
1 | /* |
2 | * PDKIM - a RFC4871 (DKIM) implementation | |
3 | * | |
f444c2c7 | 4 | * Copyright (C) 2009 - 2016 Tom Kistner <tom@duncanthrax.net> |
d4e5e70b | 5 | * Copyright (C) 2016 - 2017 Jeremy Harris <jgh@exim.org> |
80a47a2c TK |
6 | * |
7 | * http://duncanthrax.net/pdkim/ | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License along | |
20 | * with this program; if not, write to the Free Software Foundation, Inc., | |
21 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
22 | */ | |
23 | ||
0d04a285 | 24 | #include "../exim.h" |
80a47a2c | 25 | |
f444c2c7 JH |
26 | |
27 | #ifndef DISABLE_DKIM /* entire file */ | |
28 | ||
29 | #ifndef SUPPORT_TLS | |
30 | # error Need SUPPORT_TLS for DKIM | |
31 | #endif | |
32 | ||
cb224393 | 33 | #include "crypt_ver.h" |
f444c2c7 | 34 | |
cb224393 JH |
35 | #ifdef RSA_OPENSSL |
36 | # include <openssl/rsa.h> | |
37 | # include <openssl/ssl.h> | |
38 | # include <openssl/err.h> | |
39 | #elif defined(RSA_GNUTLS) | |
f444c2c7 JH |
40 | # include <gnutls/gnutls.h> |
41 | # include <gnutls/x509.h> | |
f444c2c7 JH |
42 | #endif |
43 | ||
44 | #include "pdkim.h" | |
2592e6c0 | 45 | #include "rsa.h" |
80a47a2c TK |
46 | |
47 | #define PDKIM_SIGNATURE_VERSION "1" | |
e2e3255a | 48 | #define PDKIM_PUB_RECORD_VERSION US "DKIM1" |
80a47a2c TK |
49 | |
50 | #define PDKIM_MAX_HEADER_LEN 65536 | |
51 | #define PDKIM_MAX_HEADERS 512 | |
52 | #define PDKIM_MAX_BODY_LINE_LEN 16384 | |
53 | #define PDKIM_DNS_TXT_MAX_NAMELEN 1024 | |
54 | #define PDKIM_DEFAULT_SIGN_HEADERS "From:Sender:Reply-To:Subject:Date:"\ | |
55 | "Message-ID:To:Cc:MIME-Version:Content-Type:"\ | |
56 | "Content-Transfer-Encoding:Content-ID:"\ | |
57 | "Content-Description:Resent-Date:Resent-From:"\ | |
58 | "Resent-Sender:Resent-To:Resent-Cc:"\ | |
59 | "Resent-Message-ID:In-Reply-To:References:"\ | |
60 | "List-Id:List-Help:List-Unsubscribe:"\ | |
61 | "List-Subscribe:List-Post:List-Owner:List-Archive" | |
62 | ||
63 | /* -------------------------------------------------------------------------- */ | |
64 | struct pdkim_stringlist { | |
e2e3255a JH |
65 | uschar * value; |
66 | int tag; | |
67 | void * next; | |
80a47a2c TK |
68 | }; |
69 | ||
80a47a2c TK |
70 | /* -------------------------------------------------------------------------- */ |
71 | /* A bunch of list constants */ | |
e2e3255a JH |
72 | const uschar * pdkim_querymethods[] = { |
73 | US"dns/txt", | |
80a47a2c TK |
74 | NULL |
75 | }; | |
e2e3255a JH |
76 | const uschar * pdkim_algos[] = { |
77 | US"rsa-sha256", | |
78 | US"rsa-sha1", | |
80a47a2c TK |
79 | NULL |
80 | }; | |
e2e3255a JH |
81 | const uschar * pdkim_canons[] = { |
82 | US"simple", | |
83 | US"relaxed", | |
80a47a2c TK |
84 | NULL |
85 | }; | |
e2e3255a JH |
86 | const uschar * pdkim_hashes[] = { |
87 | US"sha256", | |
88 | US"sha1", | |
80a47a2c TK |
89 | NULL |
90 | }; | |
e2e3255a JH |
91 | const uschar * pdkim_keytypes[] = { |
92 | US"rsa", | |
80a47a2c TK |
93 | NULL |
94 | }; | |
95 | ||
96 | typedef struct pdkim_combined_canon_entry { | |
e2e3255a | 97 | const uschar * str; |
80a47a2c TK |
98 | int canon_headers; |
99 | int canon_body; | |
100 | } pdkim_combined_canon_entry; | |
f444c2c7 | 101 | |
80a47a2c | 102 | pdkim_combined_canon_entry pdkim_combined_canons[] = { |
e2e3255a JH |
103 | { US"simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, |
104 | { US"simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED }, | |
105 | { US"relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, | |
106 | { US"relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED }, | |
107 | { US"simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, | |
108 | { US"relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, | |
109 | { NULL, 0, 0 } | |
80a47a2c TK |
110 | }; |
111 | ||
112 | ||
f444c2c7 JH |
113 | /* -------------------------------------------------------------------------- */ |
114 | ||
115 | const char * | |
116 | pdkim_verify_status_str(int status) | |
117 | { | |
f7302073 JH |
118 | switch(status) |
119 | { | |
120 | case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE"; | |
121 | case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID"; | |
122 | case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL"; | |
123 | case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS"; | |
124 | default: return "PDKIM_VERIFY_UNKNOWN"; | |
ff7ddfd7 TK |
125 | } |
126 | } | |
f444c2c7 JH |
127 | |
128 | const char * | |
129 | pdkim_verify_ext_status_str(int ext_status) | |
130 | { | |
f7302073 JH |
131 | switch(ext_status) |
132 | { | |
133 | case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY"; | |
134 | case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE"; | |
135 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE"; | |
136 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE"; | |
137 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD"; | |
138 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT"; | |
139 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: return "PDKIM_VERIFY_INVALID_SIGNATURE_ERROR"; | |
140 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: return "PDKIM_VERIFY_INVALID_DKIM_VERSION"; | |
141 | default: return "PDKIM_VERIFY_UNKNOWN"; | |
142 | } | |
143 | } | |
144 | ||
b9df1829 | 145 | const uschar * |
f7302073 JH |
146 | pdkim_errstr(int status) |
147 | { | |
148 | switch(status) | |
149 | { | |
b9df1829 JH |
150 | case PDKIM_OK: return US"OK"; |
151 | case PDKIM_FAIL: return US"FAIL"; | |
152 | case PDKIM_ERR_RSA_PRIVKEY: return US"RSA_PRIVKEY"; | |
153 | case PDKIM_ERR_RSA_SIGNING: return US"RSA SIGNING"; | |
154 | case PDKIM_ERR_LONG_LINE: return US"RSA_LONG_LINE"; | |
155 | case PDKIM_ERR_BUFFER_TOO_SMALL: return US"BUFFER_TOO_SMALL"; | |
156 | case PDKIM_SIGN_PRIVKEY_WRAP: return US"PRIVKEY_WRAP"; | |
157 | case PDKIM_SIGN_PRIVKEY_B64D: return US"PRIVKEY_B64D"; | |
f7302073 | 158 | default: return "(unknown)"; |
ff7ddfd7 TK |
159 | } |
160 | } | |
161 | ||
162 | ||
80a47a2c TK |
163 | /* -------------------------------------------------------------------------- */ |
164 | /* Print debugging functions */ | |
2592e6c0 | 165 | static void |
b78006ac | 166 | pdkim_quoteprint(const uschar *data, int len) |
3045f050 JH |
167 | { |
168 | int i; | |
0d04a285 | 169 | for (i = 0; i < len; i++) |
3045f050 | 170 | { |
b78006ac | 171 | const int c = data[i]; |
3045f050 JH |
172 | switch (c) |
173 | { | |
0d04a285 JH |
174 | case ' ' : debug_printf("{SP}"); break; |
175 | case '\t': debug_printf("{TB}"); break; | |
176 | case '\r': debug_printf("{CR}"); break; | |
177 | case '\n': debug_printf("{LF}"); break; | |
178 | case '{' : debug_printf("{BO}"); break; | |
179 | case '}' : debug_printf("{BC}"); break; | |
3045f050 JH |
180 | default: |
181 | if ( (c < 32) || (c > 127) ) | |
0d04a285 | 182 | debug_printf("{%02x}", c); |
3045f050 | 183 | else |
0d04a285 | 184 | debug_printf("%c", c); |
80a47a2c TK |
185 | break; |
186 | } | |
187 | } | |
2592e6c0 | 188 | debug_printf("\n"); |
80a47a2c | 189 | } |
80a47a2c | 190 | |
2592e6c0 | 191 | static void |
b78006ac | 192 | pdkim_hexprint(const uschar *data, int len) |
3045f050 JH |
193 | { |
194 | int i; | |
02c4f8fb JH |
195 | if (data) for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]); |
196 | else debug_printf("<NULL>"); | |
2592e6c0 | 197 | debug_printf("\n"); |
80a47a2c | 198 | } |
80a47a2c TK |
199 | |
200 | ||
f444c2c7 | 201 | |
f444c2c7 | 202 | static pdkim_stringlist * |
ca9cb170 | 203 | pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str) |
3045f050 | 204 | { |
ca9cb170 | 205 | pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist)); |
3045f050 | 206 | |
abe1010c | 207 | memset(new_entry, 0, sizeof(pdkim_stringlist)); |
ca9cb170 | 208 | new_entry->value = string_copy(str); |
ab9152ff JH |
209 | if (base) new_entry->next = base; |
210 | return new_entry; | |
6ab02e3f | 211 | } |
80a47a2c TK |
212 | |
213 | ||
8ef02a06 JH |
214 | |
215 | /* Trim whitespace fore & aft */ | |
216 | ||
ca9cb170 JH |
217 | static void |
218 | pdkim_strtrim(uschar * str) | |
3045f050 | 219 | { |
ca9cb170 JH |
220 | uschar * p = str; |
221 | uschar * q = str; | |
8ef02a06 JH |
222 | while (*p == '\t' || *p == ' ') p++; /* skip whitespace */ |
223 | while (*p) {*q = *p; q++; p++;} /* dump the leading whitespace */ | |
3045f050 | 224 | *q = '\0'; |
ca9cb170 | 225 | while (q != str && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) ) |
8ef02a06 | 226 | { /* dump trailing whitespace */ |
80a47a2c | 227 | *q = '\0'; |
3045f050 | 228 | q--; |
80a47a2c | 229 | } |
8ef02a06 JH |
230 | } |
231 | ||
232 | ||
80a47a2c | 233 | |
80a47a2c | 234 | /* -------------------------------------------------------------------------- */ |
3045f050 JH |
235 | |
236 | DLLEXPORT void | |
237 | pdkim_free_ctx(pdkim_ctx *ctx) | |
238 | { | |
6ab02e3f | 239 | } |
80a47a2c TK |
240 | |
241 | ||
242 | /* -------------------------------------------------------------------------- */ | |
243 | /* Matches the name of the passed raw "header" against | |
8ef02a06 JH |
244 | the passed colon-separated "tick", and invalidates |
245 | the entry in tick. Returns OK or fail-code */ | |
246 | /*XXX might be safer done using a pdkim_stringlist for "tick" */ | |
3045f050 | 247 | |
f444c2c7 | 248 | static int |
e2e3255a | 249 | header_name_match(const uschar * header, uschar * tick) |
3045f050 | 250 | { |
ca9cb170 JH |
251 | uschar * hname; |
252 | uschar * lcopy; | |
253 | uschar * p; | |
254 | uschar * q; | |
255 | uschar * hcolon = Ustrchr(header, ':'); /* Get header name */ | |
3045f050 | 256 | |
ca9cb170 JH |
257 | if (!hcolon) |
258 | return PDKIM_FAIL; /* This isn't a header */ | |
3045f050 | 259 | |
ca9cb170 JH |
260 | /* if we had strncmpic() we wouldn't need this copy */ |
261 | hname = string_copyn(header, hcolon-header); | |
3045f050 JH |
262 | |
263 | /* Copy tick-off list locally, so we can punch zeroes into it */ | |
ca9cb170 JH |
264 | p = lcopy = string_copy(tick); |
265 | ||
266 | for (q = Ustrchr(p, ':'); q; q = Ustrchr(p, ':')) | |
3045f050 JH |
267 | { |
268 | *q = '\0'; | |
ca9cb170 JH |
269 | if (strcmpic(p, hname) == 0) |
270 | goto found; | |
80a47a2c | 271 | |
3045f050 | 272 | p = q+1; |
80a47a2c TK |
273 | } |
274 | ||
ca9cb170 JH |
275 | if (strcmpic(p, hname) == 0) |
276 | goto found; | |
277 | ||
278 | return PDKIM_FAIL; | |
279 | ||
280 | found: | |
3045f050 | 281 | /* Invalidate header name instance in tick-off list */ |
8ef02a06 | 282 | tick[p-lcopy] = '_'; |
ca9cb170 | 283 | return PDKIM_OK; |
80a47a2c TK |
284 | } |
285 | ||
286 | ||
287 | /* -------------------------------------------------------------------------- */ | |
ca9cb170 | 288 | /* Performs "relaxed" canonicalization of a header. */ |
3045f050 | 289 | |
ca9cb170 JH |
290 | static uschar * |
291 | pdkim_relax_header(const uschar * header, int crlf) | |
3045f050 JH |
292 | { |
293 | BOOL past_field_name = FALSE; | |
294 | BOOL seen_wsp = FALSE; | |
ca9cb170 JH |
295 | const uschar * p; |
296 | uschar * relaxed = store_get(Ustrlen(header)+3); | |
297 | uschar * q = relaxed; | |
3045f050 | 298 | |
ca9cb170 | 299 | for (p = header; *p; p++) |
3045f050 | 300 | { |
ca9cb170 | 301 | uschar c = *p; |
3045f050 JH |
302 | /* Ignore CR & LF */ |
303 | if (c == '\r' || c == '\n') | |
304 | continue; | |
305 | if (c == '\t' || c == ' ') | |
306 | { | |
307 | if (seen_wsp) | |
80a47a2c | 308 | continue; |
3045f050 JH |
309 | c = ' '; /* Turns WSP into SP */ |
310 | seen_wsp = TRUE; | |
80a47a2c | 311 | } |
3045f050 JH |
312 | else |
313 | if (!past_field_name && c == ':') | |
314 | { | |
315 | if (seen_wsp) q--; /* This removes WSP before the colon */ | |
316 | seen_wsp = TRUE; /* This removes WSP after the colon */ | |
317 | past_field_name = TRUE; | |
80a47a2c | 318 | } |
3045f050 JH |
319 | else |
320 | seen_wsp = FALSE; | |
321 | ||
322 | /* Lowercase header name */ | |
323 | if (!past_field_name) c = tolower(c); | |
324 | *q++ = c; | |
80a47a2c | 325 | } |
3045f050 JH |
326 | |
327 | if (q > relaxed && q[-1] == ' ') q--; /* Squash eventual trailing SP */ | |
3045f050 | 328 | |
ca9cb170 JH |
329 | if (crlf) { *q++ = '\r'; *q++ = '\n'; } |
330 | *q = '\0'; | |
3045f050 | 331 | return relaxed; |
6ab02e3f | 332 | } |
80a47a2c TK |
333 | |
334 | ||
335 | /* -------------------------------------------------------------------------- */ | |
336 | #define PDKIM_QP_ERROR_DECODE -1 | |
3045f050 | 337 | |
e2e3255a JH |
338 | static uschar * |
339 | pdkim_decode_qp_char(uschar *qp_p, int *c) | |
3045f050 | 340 | { |
e2e3255a | 341 | uschar *initial_pos = qp_p; |
3045f050 JH |
342 | |
343 | /* Advance one char */ | |
344 | qp_p++; | |
345 | ||
346 | /* Check for two hex digits and decode them */ | |
347 | if (isxdigit(*qp_p) && isxdigit(qp_p[1])) | |
348 | { | |
349 | /* Do hex conversion */ | |
350 | *c = (isdigit(*qp_p) ? *qp_p - '0' : toupper(*qp_p) - 'A' + 10) << 4; | |
a5840e10 | 351 | *c |= isdigit(qp_p[1]) ? qp_p[1] - '0' : toupper(qp_p[1]) - 'A' + 10; |
3045f050 | 352 | return qp_p + 2; |
6ab02e3f | 353 | } |
80a47a2c | 354 | |
3045f050 JH |
355 | /* Illegal char here */ |
356 | *c = PDKIM_QP_ERROR_DECODE; | |
357 | return initial_pos; | |
80a47a2c TK |
358 | } |
359 | ||
360 | ||
361 | /* -------------------------------------------------------------------------- */ | |
3045f050 | 362 | |
e2e3255a | 363 | static uschar * |
ca9cb170 | 364 | pdkim_decode_qp(uschar * str) |
3045f050 JH |
365 | { |
366 | int nchar = 0; | |
ca9cb170 JH |
367 | uschar * q; |
368 | uschar * p = str; | |
369 | uschar * n = store_get(Ustrlen(str)+1); | |
3045f050 JH |
370 | |
371 | *n = '\0'; | |
372 | q = n; | |
ca9cb170 | 373 | while (*p) |
3045f050 JH |
374 | { |
375 | if (*p == '=') | |
376 | { | |
377 | p = pdkim_decode_qp_char(p, &nchar); | |
378 | if (nchar >= 0) | |
379 | { | |
380 | *q++ = nchar; | |
381 | continue; | |
80a47a2c TK |
382 | } |
383 | } | |
3045f050 JH |
384 | else |
385 | *q++ = *p; | |
386 | p++; | |
80a47a2c | 387 | } |
3045f050 JH |
388 | *q = '\0'; |
389 | return n; | |
80a47a2c TK |
390 | } |
391 | ||
392 | ||
393 | /* -------------------------------------------------------------------------- */ | |
3045f050 | 394 | |
2592e6c0 JH |
395 | static void |
396 | pdkim_decode_base64(uschar *str, blob * b) | |
3045f050 | 397 | { |
2592e6c0 | 398 | int dlen; |
2592e6c0 JH |
399 | dlen = b64decode(str, &b->data); |
400 | if (dlen < 0) b->data = NULL; | |
401 | b->len = dlen; | |
80a47a2c TK |
402 | } |
403 | ||
ca9cb170 | 404 | static uschar * |
2592e6c0 | 405 | pdkim_encode_base64(blob * b) |
3045f050 | 406 | { |
ca9cb170 | 407 | return b64encode(b->data, b->len); |
80a47a2c TK |
408 | } |
409 | ||
410 | ||
411 | /* -------------------------------------------------------------------------- */ | |
412 | #define PDKIM_HDR_LIMBO 0 | |
413 | #define PDKIM_HDR_TAG 1 | |
414 | #define PDKIM_HDR_VALUE 2 | |
3045f050 | 415 | |
f444c2c7 | 416 | static pdkim_signature * |
ca9cb170 | 417 | pdkim_parse_sig_header(pdkim_ctx *ctx, uschar * raw_hdr) |
3045f050 | 418 | { |
2c0f3ea1 | 419 | pdkim_signature * sig; |
ca9cb170 JH |
420 | uschar *p, *q; |
421 | uschar * cur_tag = NULL; int ts = 0, tl = 0; | |
422 | uschar * cur_val = NULL; int vs = 0, vl = 0; | |
3045f050 JH |
423 | BOOL past_hname = FALSE; |
424 | BOOL in_b_val = FALSE; | |
425 | int where = PDKIM_HDR_LIMBO; | |
426 | int i; | |
427 | ||
ca9cb170 | 428 | sig = store_get(sizeof(pdkim_signature)); |
abe1010c | 429 | memset(sig, 0, sizeof(pdkim_signature)); |
3045f050 JH |
430 | sig->bodylength = -1; |
431 | ||
07eeb4df | 432 | /* Set so invalid/missing data error display is accurate */ |
433 | sig->algo = -1; | |
434 | sig->version = 0; | |
435 | ||
ca9cb170 | 436 | q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1); |
80a47a2c | 437 | |
3045f050 JH |
438 | for (p = raw_hdr; ; p++) |
439 | { | |
440 | char c = *p; | |
80a47a2c | 441 | |
3045f050 JH |
442 | /* Ignore FWS */ |
443 | if (c == '\r' || c == '\n') | |
444 | goto NEXT_CHAR; | |
80a47a2c | 445 | |
3045f050 JH |
446 | /* Fast-forward through header name */ |
447 | if (!past_hname) | |
448 | { | |
449 | if (c == ':') past_hname = TRUE; | |
450 | goto NEXT_CHAR; | |
80a47a2c TK |
451 | } |
452 | ||
3045f050 JH |
453 | if (where == PDKIM_HDR_LIMBO) |
454 | { | |
455 | /* In limbo, just wait for a tag-char to appear */ | |
456 | if (!(c >= 'a' && c <= 'z')) | |
457 | goto NEXT_CHAR; | |
80a47a2c | 458 | |
3045f050 | 459 | where = PDKIM_HDR_TAG; |
80a47a2c TK |
460 | } |
461 | ||
3045f050 JH |
462 | if (where == PDKIM_HDR_TAG) |
463 | { | |
3045f050 | 464 | if (c >= 'a' && c <= 'z') |
c2f669a4 | 465 | cur_tag = string_catn(cur_tag, &ts, &tl, p, 1); |
80a47a2c | 466 | |
3045f050 JH |
467 | if (c == '=') |
468 | { | |
ca9cb170 JH |
469 | cur_tag[tl] = '\0'; |
470 | if (Ustrcmp(cur_tag, "b") == 0) | |
3045f050 | 471 | { |
ca9cb170 | 472 | *q++ = '='; |
3045f050 JH |
473 | in_b_val = TRUE; |
474 | } | |
475 | where = PDKIM_HDR_VALUE; | |
476 | goto NEXT_CHAR; | |
80a47a2c TK |
477 | } |
478 | } | |
479 | ||
3045f050 JH |
480 | if (where == PDKIM_HDR_VALUE) |
481 | { | |
3045f050 JH |
482 | if (c == '\r' || c == '\n' || c == ' ' || c == '\t') |
483 | goto NEXT_CHAR; | |
484 | ||
485 | if (c == ';' || c == '\0') | |
486 | { | |
ca9cb170 | 487 | if (tl && vl) |
3045f050 | 488 | { |
ca9cb170 | 489 | cur_val[vl] = '\0'; |
3045f050 JH |
490 | pdkim_strtrim(cur_val); |
491 | ||
ca9cb170 | 492 | DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val); |
3045f050 | 493 | |
ca9cb170 | 494 | switch (*cur_tag) |
3045f050 JH |
495 | { |
496 | case 'b': | |
dcd03763 JH |
497 | pdkim_decode_base64(cur_val, |
498 | cur_tag[1] == 'h' ? &sig->bodyhash : &sig->sighash); | |
3045f050 JH |
499 | break; |
500 | case 'v': | |
501 | /* We only support version 1, and that is currently the | |
502 | only version there is. */ | |
07eeb4df | 503 | sig->version = |
504 | Ustrcmp(cur_val, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1; | |
3045f050 JH |
505 | break; |
506 | case 'a': | |
507 | for (i = 0; pdkim_algos[i]; i++) | |
ca9cb170 | 508 | if (Ustrcmp(cur_val, pdkim_algos[i]) == 0) |
3045f050 JH |
509 | { |
510 | sig->algo = i; | |
511 | break; | |
512 | } | |
513 | break; | |
514 | case 'c': | |
515 | for (i = 0; pdkim_combined_canons[i].str; i++) | |
ca9cb170 | 516 | if (Ustrcmp(cur_val, pdkim_combined_canons[i].str) == 0) |
3045f050 JH |
517 | { |
518 | sig->canon_headers = pdkim_combined_canons[i].canon_headers; | |
519 | sig->canon_body = pdkim_combined_canons[i].canon_body; | |
520 | break; | |
521 | } | |
522 | break; | |
523 | case 'q': | |
524 | for (i = 0; pdkim_querymethods[i]; i++) | |
ca9cb170 | 525 | if (Ustrcmp(cur_val, pdkim_querymethods[i]) == 0) |
3045f050 JH |
526 | { |
527 | sig->querymethod = i; | |
528 | break; | |
529 | } | |
530 | break; | |
531 | case 's': | |
ca9cb170 | 532 | sig->selector = string_copy(cur_val); break; |
3045f050 | 533 | case 'd': |
ca9cb170 | 534 | sig->domain = string_copy(cur_val); break; |
3045f050 | 535 | case 'i': |
ca9cb170 | 536 | sig->identity = pdkim_decode_qp(cur_val); break; |
3045f050 | 537 | case 't': |
ca9cb170 | 538 | sig->created = strtoul(CS cur_val, NULL, 10); break; |
3045f050 | 539 | case 'x': |
ca9cb170 | 540 | sig->expires = strtoul(CS cur_val, NULL, 10); break; |
3045f050 | 541 | case 'l': |
ca9cb170 | 542 | sig->bodylength = strtol(CS cur_val, NULL, 10); break; |
3045f050 | 543 | case 'h': |
ca9cb170 | 544 | sig->headernames = string_copy(cur_val); break; |
3045f050 | 545 | case 'z': |
ca9cb170 | 546 | sig->copiedheaders = pdkim_decode_qp(cur_val); break; |
3045f050 | 547 | default: |
0d04a285 | 548 | DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); |
3045f050 JH |
549 | break; |
550 | } | |
551 | } | |
ca9cb170 JH |
552 | tl = 0; |
553 | vl = 0; | |
3045f050 JH |
554 | in_b_val = FALSE; |
555 | where = PDKIM_HDR_LIMBO; | |
80a47a2c | 556 | } |
3045f050 | 557 | else |
c2f669a4 | 558 | cur_val = string_catn(cur_val, &vs, &vl, p, 1); |
80a47a2c TK |
559 | } |
560 | ||
3045f050 JH |
561 | NEXT_CHAR: |
562 | if (c == '\0') | |
563 | break; | |
80a47a2c | 564 | |
3045f050 JH |
565 | if (!in_b_val) |
566 | *q++ = c; | |
80a47a2c TK |
567 | } |
568 | ||
3045f050 JH |
569 | *q = '\0'; |
570 | /* Chomp raw header. The final newline must not be added to the signature. */ | |
37f3dc43 JH |
571 | while (--q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n')) |
572 | *q = '\0'; | |
80a47a2c | 573 | |
0d04a285 | 574 | DEBUG(D_acl) |
3045f050 | 575 | { |
0d04a285 | 576 | debug_printf( |
3045f050 | 577 | "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
e2e3255a | 578 | pdkim_quoteprint(US sig->rawsig_no_b_val, Ustrlen(sig->rawsig_no_b_val)); |
0d04a285 | 579 | debug_printf( |
dcd03763 | 580 | "PDKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8); |
0d04a285 | 581 | debug_printf( |
3045f050 | 582 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
80a47a2c | 583 | } |
80a47a2c | 584 | |
7b83389d JH |
585 | if (!exim_sha_init(&sig->body_hash_ctx, |
586 | sig->algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) | |
587 | { | |
588 | DEBUG(D_acl) debug_printf("PDKIM: hash init internal error\n"); | |
589 | return NULL; | |
590 | } | |
3045f050 | 591 | return sig; |
80a47a2c TK |
592 | } |
593 | ||
594 | ||
595 | /* -------------------------------------------------------------------------- */ | |
80a47a2c | 596 | |
f444c2c7 | 597 | static pdkim_pubkey * |
e2e3255a | 598 | pdkim_parse_pubkey_record(pdkim_ctx *ctx, const uschar *raw_record) |
3045f050 JH |
599 | { |
600 | pdkim_pubkey *pub; | |
e2e3255a | 601 | const uschar *p; |
ca9cb170 JH |
602 | uschar * cur_tag = NULL; int ts = 0, tl = 0; |
603 | uschar * cur_val = NULL; int vs = 0, vl = 0; | |
3045f050 | 604 | int where = PDKIM_HDR_LIMBO; |
80a47a2c | 605 | |
ca9cb170 | 606 | pub = store_get(sizeof(pdkim_pubkey)); |
abe1010c | 607 | memset(pub, 0, sizeof(pdkim_pubkey)); |
80a47a2c | 608 | |
3045f050 | 609 | for (p = raw_record; ; p++) |
3045f050 | 610 | { |
e21a4d00 | 611 | uschar c = *p; |
80a47a2c | 612 | |
e21a4d00 JH |
613 | /* Ignore FWS */ |
614 | if (c != '\r' && c != '\n') switch (where) | |
3045f050 | 615 | { |
e21a4d00 JH |
616 | case PDKIM_HDR_LIMBO: /* In limbo, just wait for a tag-char to appear */ |
617 | if (!(c >= 'a' && c <= 'z')) | |
618 | break; | |
619 | where = PDKIM_HDR_TAG; | |
620 | /*FALLTHROUGH*/ | |
80a47a2c | 621 | |
e21a4d00 JH |
622 | case PDKIM_HDR_TAG: |
623 | if (c >= 'a' && c <= 'z') | |
624 | cur_tag = string_catn(cur_tag, &ts, &tl, p, 1); | |
3045f050 | 625 | |
e21a4d00 | 626 | if (c == '=') |
3045f050 | 627 | { |
e21a4d00 JH |
628 | cur_tag[tl] = '\0'; |
629 | where = PDKIM_HDR_VALUE; | |
3045f050 | 630 | } |
e21a4d00 JH |
631 | break; |
632 | ||
633 | case PDKIM_HDR_VALUE: | |
634 | if (c == ';' || c == '\0') | |
635 | { | |
636 | if (tl && vl) | |
637 | { | |
638 | cur_val[vl] = '\0'; | |
639 | pdkim_strtrim(cur_val); | |
640 | DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val); | |
641 | ||
642 | switch (cur_tag[0]) | |
643 | { | |
644 | case 'v': | |
645 | pub->version = string_copy(cur_val); break; | |
646 | case 'h': | |
647 | case 'k': | |
648 | /* This field appears to never be used. Also, unclear why | |
649 | a 'k' (key-type_ would go in this field name. There is a field | |
650 | "keytype", also never used. | |
651 | pub->hashes = string_copy(cur_val); | |
652 | */ | |
653 | break; | |
654 | case 'g': | |
655 | pub->granularity = string_copy(cur_val); break; | |
656 | case 'n': | |
657 | pub->notes = pdkim_decode_qp(cur_val); break; | |
658 | case 'p': | |
659 | pdkim_decode_base64(US cur_val, &pub->key); break; | |
660 | case 's': | |
661 | pub->srvtype = string_copy(cur_val); break; | |
662 | case 't': | |
663 | if (Ustrchr(cur_val, 'y') != NULL) pub->testing = 1; | |
664 | if (Ustrchr(cur_val, 's') != NULL) pub->no_subdomaining = 1; | |
665 | break; | |
666 | default: | |
667 | DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); | |
668 | break; | |
669 | } | |
670 | } | |
671 | tl = 0; | |
672 | vl = 0; | |
673 | where = PDKIM_HDR_LIMBO; | |
674 | } | |
675 | else | |
676 | cur_val = string_catn(cur_val, &vs, &vl, p, 1); | |
677 | break; | |
80a47a2c | 678 | } |
80a47a2c | 679 | |
e21a4d00 JH |
680 | if (c == '\0') break; |
681 | } | |
80a47a2c | 682 | |
3045f050 | 683 | /* Set fallback defaults */ |
ca9cb170 | 684 | if (!pub->version ) pub->version = string_copy(PDKIM_PUB_RECORD_VERSION); |
e21a4d00 JH |
685 | else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0) return NULL; |
686 | ||
ca9cb170 | 687 | if (!pub->granularity) pub->granularity = string_copy(US"*"); |
e21a4d00 | 688 | /* |
e2e3255a | 689 | if (!pub->keytype ) pub->keytype = string_copy(US"rsa"); |
e21a4d00 | 690 | */ |
ca9cb170 | 691 | if (!pub->srvtype ) pub->srvtype = string_copy(US"*"); |
80a47a2c | 692 | |
3045f050 | 693 | /* p= is required */ |
2592e6c0 | 694 | if (pub->key.data) |
80a47a2c | 695 | return pub; |
3045f050 | 696 | |
3045f050 | 697 | return NULL; |
80a47a2c TK |
698 | } |
699 | ||
700 | ||
701 | /* -------------------------------------------------------------------------- */ | |
3045f050 | 702 | |
f444c2c7 | 703 | static int |
dcd03763 | 704 | pdkim_update_bodyhash(pdkim_ctx * ctx, const char * data, int len) |
3045f050 | 705 | { |
dcd03763 JH |
706 | pdkim_signature * sig; |
707 | uschar * relaxed_data = NULL; /* Cache relaxed version of data */ | |
708 | int relaxed_len = 0; | |
3045f050 JH |
709 | |
710 | /* Traverse all signatures, updating their hashes. */ | |
dcd03763 | 711 | for (sig = ctx->sig; sig; sig = sig->next) |
3045f050 JH |
712 | { |
713 | /* Defaults to simple canon (no further treatment necessary) */ | |
b78006ac JH |
714 | const uschar *canon_data = CUS data; |
715 | int canon_len = len; | |
3045f050 JH |
716 | |
717 | if (sig->canon_body == PDKIM_CANON_RELAXED) | |
718 | { | |
719 | /* Relax the line if not done already */ | |
720 | if (!relaxed_data) | |
721 | { | |
722 | BOOL seen_wsp = FALSE; | |
723 | const char *p; | |
724 | int q = 0; | |
725 | ||
d5bccfc8 JH |
726 | /* We want to be able to free this else we allocate |
727 | for the entire message which could be many MB. Since | |
728 | we don't know what allocations the SHA routines might | |
729 | do, not safe to use store_get()/store_reset(). */ | |
730 | ||
40c90bca | 731 | relaxed_data = store_malloc(len+1); |
3045f050 JH |
732 | |
733 | for (p = data; *p; p++) | |
734 | { | |
735 | char c = *p; | |
736 | if (c == '\r') | |
737 | { | |
738 | if (q > 0 && relaxed_data[q-1] == ' ') | |
739 | q--; | |
740 | } | |
741 | else if (c == '\t' || c == ' ') | |
742 | { | |
743 | c = ' '; /* Turns WSP into SP */ | |
744 | if (seen_wsp) | |
745 | continue; | |
746 | seen_wsp = TRUE; | |
747 | } | |
748 | else | |
749 | seen_wsp = FALSE; | |
750 | relaxed_data[q++] = c; | |
751 | } | |
752 | relaxed_data[q] = '\0'; | |
753 | relaxed_len = q; | |
80a47a2c | 754 | } |
3045f050 JH |
755 | canon_data = relaxed_data; |
756 | canon_len = relaxed_len; | |
80a47a2c TK |
757 | } |
758 | ||
3045f050 JH |
759 | /* Make sure we don't exceed the to-be-signed body length */ |
760 | if ( sig->bodylength >= 0 | |
761 | && sig->signed_body_bytes + (unsigned long)canon_len > sig->bodylength | |
762 | ) | |
763 | canon_len = sig->bodylength - sig->signed_body_bytes; | |
80a47a2c | 764 | |
3045f050 JH |
765 | if (canon_len > 0) |
766 | { | |
dcd03763 | 767 | exim_sha_update(&sig->body_hash_ctx, CUS canon_data, canon_len); |
3045f050 | 768 | sig->signed_body_bytes += canon_len; |
2592e6c0 | 769 | DEBUG(D_acl) pdkim_quoteprint(canon_data, canon_len); |
80a47a2c | 770 | } |
80a47a2c TK |
771 | } |
772 | ||
40c90bca | 773 | if (relaxed_data) store_free(relaxed_data); |
3045f050 | 774 | return PDKIM_OK; |
6ab02e3f | 775 | } |
80a47a2c TK |
776 | |
777 | ||
778 | /* -------------------------------------------------------------------------- */ | |
80a47a2c | 779 | |
ca9cb170 | 780 | static void |
3045f050 JH |
781 | pdkim_finish_bodyhash(pdkim_ctx *ctx) |
782 | { | |
f4d091fb | 783 | pdkim_signature *sig; |
80a47a2c | 784 | |
3045f050 | 785 | /* Traverse all signatures */ |
f4d091fb | 786 | for (sig = ctx->sig; sig; sig = sig->next) |
3045f050 | 787 | { /* Finish hashes */ |
2592e6c0 JH |
788 | blob bh; |
789 | ||
dcd03763 | 790 | exim_sha_finish(&sig->body_hash_ctx, &bh); |
3045f050 | 791 | |
0d04a285 | 792 | DEBUG(D_acl) |
3045f050 | 793 | { |
0d04a285 | 794 | debug_printf("PDKIM [%s] Body bytes hashed: %lu\n" |
e21a4d00 | 795 | "PDKIM [%s] Body hash computed: ", |
0d04a285 | 796 | sig->domain, sig->signed_body_bytes, sig->domain); |
b78006ac | 797 | pdkim_hexprint(CUS bh.data, bh.len); |
80a47a2c | 798 | } |
3045f050 JH |
799 | |
800 | /* SIGNING -------------------------------------------------------------- */ | |
e983e85a | 801 | if (ctx->flags & PDKIM_MODE_SIGN) |
3045f050 | 802 | { |
2592e6c0 | 803 | sig->bodyhash = bh; |
3045f050 JH |
804 | |
805 | /* If bodylength limit is set, and we have received less bytes | |
806 | than the requested amount, effectively remove the limit tag. */ | |
807 | if (sig->signed_body_bytes < sig->bodylength) | |
808 | sig->bodylength = -1; | |
80a47a2c | 809 | } |
3045f050 | 810 | |
3045f050 | 811 | else |
02c4f8fb JH |
812 | /* VERIFICATION --------------------------------------------------------- */ |
813 | /* Be careful that the header sig included a bodyash */ | |
814 | ||
815 | if (sig->bodyhash.data && memcmp(bh.data, sig->bodyhash.data, bh.len) == 0) | |
3045f050 | 816 | { |
0d04a285 | 817 | DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain); |
80a47a2c | 818 | } |
3045f050 JH |
819 | else |
820 | { | |
0d04a285 | 821 | DEBUG(D_acl) |
3045f050 | 822 | { |
e21a4d00 | 823 | debug_printf("PDKIM [%s] Body hash signature from headers: ", sig->domain); |
dcd03763 | 824 | pdkim_hexprint(sig->bodyhash.data, sig->bodyhash.len); |
0d04a285 | 825 | debug_printf("PDKIM [%s] Body hash did NOT verify\n", sig->domain); |
3045f050 | 826 | } |
3045f050 JH |
827 | sig->verify_status = PDKIM_VERIFY_FAIL; |
828 | sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY; | |
80a47a2c | 829 | } |
80a47a2c | 830 | } |
6ab02e3f | 831 | } |
80a47a2c TK |
832 | |
833 | ||
834 | ||
e983e85a JH |
835 | static int |
836 | pdkim_body_complete(pdkim_ctx * ctx) | |
837 | { | |
838 | pdkim_signature * sig = ctx->sig; /*XXX assumes only one sig */ | |
839 | ||
840 | /* In simple body mode, if any empty lines were buffered, | |
841 | replace with one. rfc 4871 3.4.3 */ | |
842 | /*XXX checking the signed-body-bytes is a gross hack; I think | |
843 | it indicates that all linebreaks should be buffered, including | |
844 | the one terminating a text line */ | |
845 | ||
846 | if ( sig && sig->canon_body == PDKIM_CANON_SIMPLE | |
847 | && sig->signed_body_bytes == 0 | |
848 | && ctx->num_buffered_crlf > 0 | |
849 | ) | |
850 | pdkim_update_bodyhash(ctx, "\r\n", 2); | |
851 | ||
852 | ctx->flags |= PDKIM_SEEN_EOD; | |
853 | ctx->linebuf_offset = 0; | |
854 | return PDKIM_OK; | |
855 | } | |
856 | ||
857 | ||
858 | ||
80a47a2c | 859 | /* -------------------------------------------------------------------------- */ |
e983e85a | 860 | /* Call from pdkim_feed below for processing complete body lines */ |
3045f050 | 861 | |
0d04a285 | 862 | static int |
3045f050 JH |
863 | pdkim_bodyline_complete(pdkim_ctx *ctx) |
864 | { | |
865 | char *p = ctx->linebuf; | |
866 | int n = ctx->linebuf_offset; | |
c14470c3 | 867 | pdkim_signature *sig = ctx->sig; /*XXX assumes only one sig */ |
3045f050 JH |
868 | |
869 | /* Ignore extra data if we've seen the end-of-data marker */ | |
e983e85a | 870 | if (ctx->flags & PDKIM_SEEN_EOD) goto BAIL; |
3045f050 JH |
871 | |
872 | /* We've always got one extra byte to stuff a zero ... */ | |
0d04a285 | 873 | ctx->linebuf[ctx->linebuf_offset] = '\0'; |
3045f050 | 874 | |
0d04a285 | 875 | /* Terminate on EOD marker */ |
e983e85a | 876 | if (ctx->flags & PDKIM_DOT_TERM) |
3045f050 | 877 | { |
b895f4b2 | 878 | if (memcmp(p, ".\r\n", 3) == 0) |
e983e85a | 879 | return pdkim_body_complete(ctx); |
0d04a285 | 880 | |
e983e85a JH |
881 | /* Unstuff dots */ |
882 | if (memcmp(p, "..", 2) == 0) | |
883 | { | |
884 | p++; | |
885 | n--; | |
886 | } | |
80a47a2c TK |
887 | } |
888 | ||
3045f050 JH |
889 | /* Empty lines need to be buffered until we find a non-empty line */ |
890 | if (memcmp(p, "\r\n", 2) == 0) | |
891 | { | |
892 | ctx->num_buffered_crlf++; | |
893 | goto BAIL; | |
80a47a2c TK |
894 | } |
895 | ||
c14470c3 | 896 | if (sig && sig->canon_body == PDKIM_CANON_RELAXED) |
3045f050 JH |
897 | { |
898 | /* Lines with just spaces need to be buffered too */ | |
899 | char *check = p; | |
900 | while (memcmp(check, "\r\n", 2) != 0) | |
901 | { | |
902 | char c = *check; | |
6a11a9e6 | 903 | |
3045f050 JH |
904 | if (c != '\t' && c != ' ') |
905 | goto PROCESS; | |
906 | check++; | |
6a11a9e6 JH |
907 | } |
908 | ||
3045f050 JH |
909 | ctx->num_buffered_crlf++; |
910 | goto BAIL; | |
911 | } | |
6a11a9e6 | 912 | |
3045f050 JH |
913 | PROCESS: |
914 | /* At this point, we have a non-empty line, so release the buffered ones. */ | |
915 | while (ctx->num_buffered_crlf) | |
916 | { | |
917 | pdkim_update_bodyhash(ctx, "\r\n", 2); | |
918 | ctx->num_buffered_crlf--; | |
80a47a2c TK |
919 | } |
920 | ||
3045f050 | 921 | pdkim_update_bodyhash(ctx, p, n); |
80a47a2c | 922 | |
3045f050 JH |
923 | BAIL: |
924 | ctx->linebuf_offset = 0; | |
925 | return PDKIM_OK; | |
80a47a2c TK |
926 | } |
927 | ||
928 | ||
929 | /* -------------------------------------------------------------------------- */ | |
930 | /* Callback from pdkim_feed below for processing complete headers */ | |
931 | #define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:" | |
3045f050 | 932 | |
f444c2c7 | 933 | static int |
2c0f3ea1 | 934 | pdkim_header_complete(pdkim_ctx * ctx) |
3045f050 | 935 | { |
2c0f3ea1 JH |
936 | pdkim_signature * sig, * last_sig; |
937 | ||
3045f050 | 938 | /* Special case: The last header can have an extra \r appended */ |
ca9cb170 JH |
939 | if ( (ctx->cur_header_len > 1) && |
940 | (ctx->cur_header[(ctx->cur_header_len)-1] == '\r') ) | |
941 | --ctx->cur_header_len; | |
942 | ctx->cur_header[ctx->cur_header_len] = '\0'; | |
80a47a2c | 943 | |
2c0f3ea1 | 944 | if (++ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL; |
80a47a2c | 945 | |
3045f050 | 946 | /* SIGNING -------------------------------------------------------------- */ |
e983e85a | 947 | if (ctx->flags & PDKIM_MODE_SIGN) |
0d04a285 | 948 | for (sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */ |
80a47a2c | 949 | |
ab9152ff | 950 | /* Add header to the signed headers list (in reverse order) */ |
ca9cb170 JH |
951 | sig->headers = pdkim_prepend_stringlist(sig->headers, |
952 | ctx->cur_header); | |
94431adb | 953 | |
0d04a285 | 954 | /* VERIFICATION ----------------------------------------------------------- */ |
3045f050 | 955 | /* DKIM-Signature: headers are added to the verification list */ |
e983e85a | 956 | else |
3045f050 | 957 | { |
f6ee24a2 | 958 | #ifdef notdef |
bd8fbe36 JH |
959 | DEBUG(D_acl) |
960 | { | |
961 | debug_printf("PDKIM >> raw hdr: "); | |
2c0f3ea1 | 962 | pdkim_quoteprint(CUS ctx->cur_header, ctx->cur_header_len); |
bd8fbe36 | 963 | } |
f6ee24a2 | 964 | #endif |
e2e3255a | 965 | if (strncasecmp(CCS ctx->cur_header, |
3045f050 | 966 | DKIM_SIGNATURE_HEADERNAME, |
e2e3255a | 967 | Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0) |
3045f050 | 968 | { |
02c4f8fb JH |
969 | /* Create and chain new signature block. We could error-check for all |
970 | required tags here, but prefer to create the internal sig and expicitly | |
971 | fail verification of it later. */ | |
80a47a2c | 972 | |
0d04a285 | 973 | DEBUG(D_acl) debug_printf( |
3045f050 | 974 | "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
3045f050 | 975 | |
2c0f3ea1 | 976 | sig = pdkim_parse_sig_header(ctx, ctx->cur_header); |
02c4f8fb JH |
977 | |
978 | if (!(last_sig = ctx->sig)) | |
2c0f3ea1 | 979 | ctx->sig = sig; |
02c4f8fb | 980 | else |
3045f050 | 981 | { |
02c4f8fb | 982 | while (last_sig->next) last_sig = last_sig->next; |
2c0f3ea1 | 983 | last_sig->next = sig; |
80a47a2c TK |
984 | } |
985 | } | |
37f8b554 | 986 | |
eea19017 JH |
987 | /* all headers are stored for signature verification */ |
988 | ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header); | |
80a47a2c TK |
989 | } |
990 | ||
3045f050 | 991 | BAIL: |
2c0f3ea1 | 992 | ctx->cur_header[ctx->cur_header_len = 0] = '\0'; /* leave buffer for reuse */ |
3045f050 | 993 | return PDKIM_OK; |
6ab02e3f | 994 | } |
80a47a2c TK |
995 | |
996 | ||
997 | ||
998 | /* -------------------------------------------------------------------------- */ | |
999 | #define HEADER_BUFFER_FRAG_SIZE 256 | |
3045f050 JH |
1000 | |
1001 | DLLEXPORT int | |
ca9cb170 | 1002 | pdkim_feed(pdkim_ctx *ctx, char *data, int len) |
3045f050 | 1003 | { |
02c4f8fb | 1004 | int p, rc; |
3045f050 | 1005 | |
e983e85a JH |
1006 | /* Alternate EOD signal, used in non-dotstuffing mode */ |
1007 | if (!data) | |
1008 | pdkim_body_complete(ctx); | |
1009 | ||
10c50704 | 1010 | else for (p = 0; p<len; p++) |
3045f050 | 1011 | { |
ca9cb170 | 1012 | uschar c = data[p]; |
3045f050 | 1013 | |
e983e85a | 1014 | if (ctx->flags & PDKIM_PAST_HDRS) |
3045f050 | 1015 | { |
b895f4b2 JH |
1016 | if (c == '\n' && !(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ |
1017 | { | |
1018 | ctx->linebuf[ctx->linebuf_offset++] = '\r'; | |
1019 | if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) | |
1020 | return PDKIM_ERR_LONG_LINE; | |
1021 | } | |
1022 | ||
3045f050 | 1023 | /* Processing body byte */ |
0d04a285 | 1024 | ctx->linebuf[ctx->linebuf_offset++] = c; |
b895f4b2 JH |
1025 | if (c == '\r') |
1026 | ctx->flags |= PDKIM_SEEN_CR; | |
1027 | else if (c == '\n') | |
3045f050 | 1028 | { |
b895f4b2 JH |
1029 | ctx->flags &= ~PDKIM_SEEN_CR; |
1030 | if ((rc = pdkim_bodyline_complete(ctx)) != PDKIM_OK) | |
1031 | return rc; | |
80a47a2c | 1032 | } |
b895f4b2 JH |
1033 | |
1034 | if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) | |
3045f050 | 1035 | return PDKIM_ERR_LONG_LINE; |
80a47a2c | 1036 | } |
3045f050 JH |
1037 | else |
1038 | { | |
1039 | /* Processing header byte */ | |
b895f4b2 JH |
1040 | if (c == '\r') |
1041 | ctx->flags |= PDKIM_SEEN_CR; | |
1042 | else if (c == '\n') | |
3045f050 | 1043 | { |
b895f4b2 JH |
1044 | if (!(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ |
1045 | ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size, | |
1046 | &ctx->cur_header_len, CUS "\r", 1); | |
1047 | ||
02c4f8fb | 1048 | if (ctx->flags & PDKIM_SEEN_LF) /* Seen last header line */ |
b895f4b2 | 1049 | { |
02c4f8fb JH |
1050 | if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) |
1051 | return rc; | |
b895f4b2 | 1052 | |
863bd541 | 1053 | ctx->flags = (ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR)) | PDKIM_PAST_HDRS; |
b895f4b2 | 1054 | DEBUG(D_acl) debug_printf( |
02c4f8fb | 1055 | "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
b895f4b2 | 1056 | continue; |
3045f050 | 1057 | } |
b895f4b2 | 1058 | else |
863bd541 | 1059 | ctx->flags = (ctx->flags & ~PDKIM_SEEN_CR) | PDKIM_SEEN_LF; |
b895f4b2 JH |
1060 | } |
1061 | else if (ctx->flags & PDKIM_SEEN_LF) | |
1062 | { | |
02c4f8fb JH |
1063 | if (!(c == '\t' || c == ' ')) /* End of header */ |
1064 | if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) | |
1065 | return rc; | |
b895f4b2 | 1066 | ctx->flags &= ~PDKIM_SEEN_LF; |
80a47a2c | 1067 | } |
3045f050 | 1068 | |
ca9cb170 | 1069 | if (ctx->cur_header_len < PDKIM_MAX_HEADER_LEN) |
c2f669a4 | 1070 | ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size, |
e2e3255a | 1071 | &ctx->cur_header_len, CUS &data[p], 1); |
80a47a2c TK |
1072 | } |
1073 | } | |
3045f050 | 1074 | return PDKIM_OK; |
6ab02e3f | 1075 | } |
80a47a2c | 1076 | |
ca9cb170 JH |
1077 | |
1078 | ||
1079 | /* Extend a grwong header with a continuation-linebreak */ | |
1080 | static uschar * | |
1081 | pdkim_hdr_cont(uschar * str, int * size, int * ptr, int * col) | |
1082 | { | |
1083 | *col = 1; | |
c2f669a4 | 1084 | return string_catn(str, size, ptr, US"\r\n\t", 3); |
ca9cb170 JH |
1085 | } |
1086 | ||
1087 | ||
1088 | ||
05b7d6de JB |
1089 | /* |
1090 | * RFC 5322 specifies that header line length SHOULD be no more than 78 | |
1091 | * lets make it so! | |
1092 | * pdkim_headcat | |
ca9cb170 JH |
1093 | * |
1094 | * returns uschar * (not nul-terminated) | |
05b7d6de JB |
1095 | * |
1096 | * col: this int holds and receives column number (octets since last '\n') | |
1097 | * str: partial string to append to | |
ca9cb170 JH |
1098 | * size: current buffer size for str |
1099 | * ptr: current tail-pointer for str | |
94431adb | 1100 | * pad: padding, split line or space after before or after eg: ";" |
05b7d6de JB |
1101 | * intro: - must join to payload eg "h=", usually the tag name |
1102 | * payload: eg base64 data - long data can be split arbitrarily. | |
1103 | * | |
1104 | * this code doesn't fold the header in some of the places that RFC4871 | |
1105 | * allows: As per RFC5322(2.2.3) it only folds before or after tag-value | |
1106 | * pairs and inside long values. it also always spaces or breaks after the | |
94431adb | 1107 | * "pad" |
05b7d6de JB |
1108 | * |
1109 | * no guarantees are made for output given out-of range input. like tag | |
f444c2c7 | 1110 | * names longer than 78, or bogus col. Input is assumed to be free of line breaks. |
05b7d6de JB |
1111 | */ |
1112 | ||
ca9cb170 JH |
1113 | static uschar * |
1114 | pdkim_headcat(int * col, uschar * str, int * size, int * ptr, | |
1115 | const uschar * pad, const uschar * intro, const uschar * payload) | |
3045f050 JH |
1116 | { |
1117 | size_t l; | |
1118 | ||
1119 | if (pad) | |
05b7d6de | 1120 | { |
ca9cb170 | 1121 | l = Ustrlen(pad); |
3045f050 | 1122 | if (*col + l > 78) |
ca9cb170 | 1123 | str = pdkim_hdr_cont(str, size, ptr, col); |
c2f669a4 | 1124 | str = string_catn(str, size, ptr, pad, l); |
3045f050 | 1125 | *col += l; |
05b7d6de JB |
1126 | } |
1127 | ||
ca9cb170 | 1128 | l = (pad?1:0) + (intro?Ustrlen(intro):0); |
05b7d6de | 1129 | |
3045f050 | 1130 | if (*col + l > 78) |
05b7d6de | 1131 | { /*can't fit intro - start a new line to make room.*/ |
ca9cb170 JH |
1132 | str = pdkim_hdr_cont(str, size, ptr, col); |
1133 | l = intro?Ustrlen(intro):0; | |
05b7d6de JB |
1134 | } |
1135 | ||
ca9cb170 | 1136 | l += payload ? Ustrlen(payload):0 ; |
05b7d6de | 1137 | |
3045f050 | 1138 | while (l>77) |
05b7d6de | 1139 | { /* this fragment will not fit on a single line */ |
3045f050 | 1140 | if (pad) |
05b7d6de | 1141 | { |
c2f669a4 | 1142 | str = string_catn(str, size, ptr, US" ", 1); |
3045f050 JH |
1143 | *col += 1; |
1144 | pad = NULL; /* only want this once */ | |
1145 | l--; | |
05b7d6de | 1146 | } |
3045f050 JH |
1147 | |
1148 | if (intro) | |
05b7d6de | 1149 | { |
ca9cb170 | 1150 | size_t sl = Ustrlen(intro); |
3045f050 | 1151 | |
c2f669a4 | 1152 | str = string_catn(str, size, ptr, intro, sl); |
3045f050 JH |
1153 | *col += sl; |
1154 | l -= sl; | |
1155 | intro = NULL; /* only want this once */ | |
05b7d6de | 1156 | } |
3045f050 JH |
1157 | |
1158 | if (payload) | |
05b7d6de | 1159 | { |
ca9cb170 | 1160 | size_t sl = Ustrlen(payload); |
3045f050 JH |
1161 | size_t chomp = *col+sl < 77 ? sl : 78-*col; |
1162 | ||
c2f669a4 | 1163 | str = string_catn(str, size, ptr, payload, chomp); |
3045f050 JH |
1164 | *col += chomp; |
1165 | payload += chomp; | |
1166 | l -= chomp-1; | |
05b7d6de | 1167 | } |
3045f050 JH |
1168 | |
1169 | /* the while precondition tells us it didn't fit. */ | |
ca9cb170 | 1170 | str = pdkim_hdr_cont(str, size, ptr, col); |
05b7d6de | 1171 | } |
3045f050 JH |
1172 | |
1173 | if (*col + l > 78) | |
05b7d6de | 1174 | { |
ca9cb170 | 1175 | str = pdkim_hdr_cont(str, size, ptr, col); |
3045f050 | 1176 | pad = NULL; |
05b7d6de JB |
1177 | } |
1178 | ||
3045f050 | 1179 | if (pad) |
05b7d6de | 1180 | { |
c2f669a4 | 1181 | str = string_catn(str, size, ptr, US" ", 1); |
3045f050 JH |
1182 | *col += 1; |
1183 | pad = NULL; | |
05b7d6de JB |
1184 | } |
1185 | ||
3045f050 | 1186 | if (intro) |
05b7d6de | 1187 | { |
ca9cb170 | 1188 | size_t sl = Ustrlen(intro); |
3045f050 | 1189 | |
c2f669a4 | 1190 | str = string_catn(str, size, ptr, intro, sl); |
3045f050 JH |
1191 | *col += sl; |
1192 | l -= sl; | |
1193 | intro = NULL; | |
05b7d6de | 1194 | } |
3045f050 JH |
1195 | |
1196 | if (payload) | |
05b7d6de | 1197 | { |
ca9cb170 | 1198 | size_t sl = Ustrlen(payload); |
3045f050 | 1199 | |
c2f669a4 | 1200 | str = string_catn(str, size, ptr, payload, sl); |
3045f050 | 1201 | *col += sl; |
05b7d6de JB |
1202 | } |
1203 | ||
ca9cb170 | 1204 | return str; |
05b7d6de | 1205 | } |
80a47a2c | 1206 | |
3045f050 | 1207 | |
80a47a2c | 1208 | /* -------------------------------------------------------------------------- */ |
3045f050 | 1209 | |
ca9cb170 | 1210 | static uschar * |
2592e6c0 | 1211 | pdkim_create_header(pdkim_signature *sig, BOOL final) |
3045f050 | 1212 | { |
ca9cb170 JH |
1213 | uschar * base64_bh; |
1214 | uschar * base64_b; | |
3045f050 | 1215 | int col = 0; |
ca9cb170 JH |
1216 | uschar * hdr; int hdr_size = 0, hdr_len = 0; |
1217 | uschar * canon_all; int can_size = 0, can_len = 0; | |
3045f050 | 1218 | |
c2f669a4 JH |
1219 | canon_all = string_cat (NULL, &can_size, &can_len, |
1220 | pdkim_canons[sig->canon_headers]); | |
1221 | canon_all = string_catn(canon_all, &can_size, &can_len, US"/", 1); | |
1222 | canon_all = string_cat (canon_all, &can_size, &can_len, | |
1223 | pdkim_canons[sig->canon_body]); | |
ca9cb170 | 1224 | canon_all[can_len] = '\0'; |
3045f050 | 1225 | |
ca9cb170 | 1226 | hdr = string_cat(NULL, &hdr_size, &hdr_len, |
e2e3255a | 1227 | US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); |
ca9cb170 | 1228 | col = hdr_len; |
3045f050 JH |
1229 | |
1230 | /* Required and static bits */ | |
ca9cb170 JH |
1231 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"a=", |
1232 | pdkim_algos[sig->algo]); | |
1233 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"q=", | |
1234 | pdkim_querymethods[sig->querymethod]); | |
1235 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"c=", | |
1236 | canon_all); | |
1237 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"d=", | |
1238 | sig->domain); | |
1239 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"s=", | |
1240 | sig->selector); | |
1241 | ||
1242 | /* list of header names can be split between items. */ | |
3045f050 | 1243 | { |
e2e3255a | 1244 | uschar * n = string_copy(sig->headernames); |
ca9cb170 JH |
1245 | uschar * i = US"h="; |
1246 | uschar * s = US";"; | |
1247 | ||
1248 | while (*n) | |
05b7d6de | 1249 | { |
ca9cb170 | 1250 | uschar * c = Ustrchr(n, ':'); |
3045f050 | 1251 | |
ca9cb170 | 1252 | if (c) *c ='\0'; |
05b7d6de | 1253 | |
ca9cb170 JH |
1254 | if (!i) |
1255 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, NULL, US":"); | |
05b7d6de | 1256 | |
ca9cb170 | 1257 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, s, i, n); |
3045f050 | 1258 | |
ca9cb170 JH |
1259 | if (!c) |
1260 | break; | |
3045f050 | 1261 | |
ca9cb170 JH |
1262 | n = c+1; |
1263 | s = NULL; | |
1264 | i = NULL; | |
80a47a2c | 1265 | } |
ca9cb170 | 1266 | } |
05b7d6de | 1267 | |
ca9cb170 JH |
1268 | base64_bh = pdkim_encode_base64(&sig->bodyhash); |
1269 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"bh=", base64_bh); | |
3045f050 | 1270 | |
ca9cb170 JH |
1271 | /* Optional bits */ |
1272 | if (sig->identity) | |
1273 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"i=", sig->identity); | |
3045f050 | 1274 | |
ca9cb170 JH |
1275 | if (sig->created > 0) |
1276 | { | |
e2e3255a | 1277 | uschar minibuf[20]; |
3045f050 | 1278 | |
e2e3255a | 1279 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created); |
ca9cb170 JH |
1280 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"t=", minibuf); |
1281 | } | |
3045f050 | 1282 | |
ca9cb170 JH |
1283 | if (sig->expires > 0) |
1284 | { | |
e2e3255a | 1285 | uschar minibuf[20]; |
3045f050 | 1286 | |
e2e3255a | 1287 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires); |
ca9cb170 JH |
1288 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"x=", minibuf); |
1289 | } | |
3045f050 | 1290 | |
ca9cb170 JH |
1291 | if (sig->bodylength >= 0) |
1292 | { | |
e2e3255a | 1293 | uschar minibuf[20]; |
80a47a2c | 1294 | |
e2e3255a | 1295 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength); |
ca9cb170 | 1296 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"l=", minibuf); |
3045f050 | 1297 | } |
05b7d6de | 1298 | |
ca9cb170 | 1299 | /* Preliminary or final version? */ |
dcd03763 | 1300 | base64_b = final ? pdkim_encode_base64(&sig->sighash) : US""; |
ca9cb170 | 1301 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"b=", base64_b); |
80a47a2c | 1302 | |
ca9cb170 JH |
1303 | /* add trailing semicolon: I'm not sure if this is actually needed */ |
1304 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, US";", US""); | |
80a47a2c | 1305 | |
ca9cb170 JH |
1306 | hdr[hdr_len] = '\0'; |
1307 | return hdr; | |
80a47a2c TK |
1308 | } |
1309 | ||
1310 | ||
cd1a5fe0 JH |
1311 | /* -------------------------------------------------------------------------- */ |
1312 | ||
1313 | static pdkim_pubkey * | |
b9df1829 JH |
1314 | pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx, |
1315 | const uschar ** errstr) | |
cd1a5fe0 JH |
1316 | { |
1317 | uschar * dns_txt_name, * dns_txt_reply; | |
1318 | pdkim_pubkey * p; | |
cd1a5fe0 JH |
1319 | |
1320 | /* Fetch public key for signing domain, from DNS */ | |
1321 | ||
1322 | dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain); | |
1323 | ||
1324 | dns_txt_reply = store_get(PDKIM_DNS_TXT_MAX_RECLEN); | |
1325 | memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN); | |
1326 | ||
1327 | if ( ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK | |
1328 | || dns_txt_reply[0] == '\0' | |
1329 | ) | |
1330 | { | |
1331 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1332 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE; | |
1333 | return NULL; | |
1334 | } | |
1335 | ||
1336 | DEBUG(D_acl) | |
1337 | { | |
1338 | debug_printf( | |
1339 | "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n" | |
1340 | " Raw record: "); | |
1341 | pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply)); | |
1342 | } | |
1343 | ||
1344 | if ( !(p = pdkim_parse_pubkey_record(ctx, CUS dns_txt_reply)) | |
1345 | || (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0) | |
1346 | ) | |
1347 | { | |
1348 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1349 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD; | |
1350 | ||
1351 | DEBUG(D_acl) | |
1352 | { | |
1353 | if (p) | |
1354 | debug_printf(" Invalid public key service type '%s'\n", p->srvtype); | |
1355 | else | |
1356 | debug_printf(" Error while parsing public key record\n"); | |
1357 | debug_printf( | |
1358 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); | |
1359 | } | |
1360 | return NULL; | |
1361 | } | |
1362 | ||
1363 | DEBUG(D_acl) debug_printf( | |
1364 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); | |
1365 | ||
1366 | /* Import public key */ | |
b9df1829 | 1367 | if ((*errstr = exim_rsa_verify_init(&p->key, vctx))) |
cd1a5fe0 | 1368 | { |
b9df1829 | 1369 | DEBUG(D_acl) debug_printf("verify_init: %s\n", *errstr); |
cd1a5fe0 JH |
1370 | sig->verify_status = PDKIM_VERIFY_INVALID; |
1371 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT; | |
1372 | return NULL; | |
1373 | } | |
1374 | ||
1375 | return p; | |
1376 | } | |
1377 | ||
1378 | ||
80a47a2c | 1379 | /* -------------------------------------------------------------------------- */ |
3045f050 JH |
1380 | |
1381 | DLLEXPORT int | |
b9df1829 JH |
1382 | pdkim_feed_finish(pdkim_ctx * ctx, pdkim_signature ** return_signatures, |
1383 | const uschar ** err) | |
3045f050 JH |
1384 | { |
1385 | pdkim_signature *sig = ctx->sig; | |
3045f050 JH |
1386 | |
1387 | /* Check if we must still flush a (partial) header. If that is the | |
1388 | case, the message has no body, and we must compute a body hash | |
1389 | out of '<CR><LF>' */ | |
ca9cb170 | 1390 | if (ctx->cur_header && ctx->cur_header_len) |
3045f050 JH |
1391 | { |
1392 | int rc = pdkim_header_complete(ctx); | |
1393 | if (rc != PDKIM_OK) return rc; | |
1394 | pdkim_update_bodyhash(ctx, "\r\n", 2); | |
80a47a2c | 1395 | } |
3045f050 | 1396 | else |
0d04a285 | 1397 | DEBUG(D_acl) debug_printf( |
3045f050 | 1398 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
80a47a2c | 1399 | |
3045f050 | 1400 | /* Build (and/or evaluate) body hash */ |
ca9cb170 | 1401 | pdkim_finish_bodyhash(ctx); |
80a47a2c | 1402 | |
3045f050 JH |
1403 | while (sig) |
1404 | { | |
2592e6c0 JH |
1405 | BOOL is_sha1 = sig->algo == PDKIM_ALGO_RSA_SHA1; |
1406 | hctx hhash_ctx; | |
ad6f5499 | 1407 | uschar * sig_hdr = US""; |
2592e6c0 JH |
1408 | blob hhash; |
1409 | blob hdata; | |
cb224393 | 1410 | int hdata_alloc = 0; |
cb224393 | 1411 | |
2592e6c0 JH |
1412 | hdata.data = NULL; |
1413 | hdata.len = 0; | |
1414 | ||
7b83389d JH |
1415 | if (!exim_sha_init(&hhash_ctx, is_sha1 ? HASH_SHA1 : HASH_SHA256)) |
1416 | { | |
1417 | DEBUG(D_acl) debug_printf("PDKIM: hask setup internal error\n"); | |
1418 | break; | |
1419 | } | |
80a47a2c | 1420 | |
0d04a285 | 1421 | DEBUG(D_acl) debug_printf( |
e21a4d00 | 1422 | "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>>>\n"); |
3045f050 JH |
1423 | |
1424 | /* SIGNING ---------------------------------------------------------------- */ | |
1425 | /* When signing, walk through our header list and add them to the hash. As we | |
8ef02a06 JH |
1426 | go, construct a list of the header's names to use for the h= parameter. |
1427 | Then append to that list any remaining header names for which there was no | |
1428 | header to sign. */ | |
3045f050 | 1429 | |
e983e85a | 1430 | if (ctx->flags & PDKIM_MODE_SIGN) |
3045f050 | 1431 | { |
10c50704 JH |
1432 | uschar * headernames = NULL; /* Collected signed header names */ |
1433 | int hs = 0, hl = 0; | |
3045f050 | 1434 | pdkim_stringlist *p; |
8ef02a06 JH |
1435 | const uschar * l; |
1436 | uschar * s; | |
1437 | int sep = 0; | |
3045f050 JH |
1438 | |
1439 | for (p = sig->headers; p; p = p->next) | |
ab9152ff JH |
1440 | if (header_name_match(p->value, sig->sign_headers) == PDKIM_OK) |
1441 | { | |
1442 | uschar * rh; | |
1443 | /* Collect header names (Note: colon presence is guaranteed here) */ | |
1444 | uschar * q = Ustrchr(p->value, ':'); | |
3045f050 | 1445 | |
c2f669a4 | 1446 | headernames = string_catn(headernames, &hs, &hl, |
ca9cb170 | 1447 | p->value, (q - US p->value) + (p->next ? 1 : 0)); |
3045f050 | 1448 | |
ab9152ff | 1449 | rh = sig->canon_headers == PDKIM_CANON_RELAXED |
ca9cb170 JH |
1450 | ? pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */ |
1451 | : string_copy(CUS p->value); /* just copy it for simple canon */ | |
3045f050 | 1452 | |
ab9152ff | 1453 | /* Feed header to the hash algorithm */ |
e2e3255a | 1454 | exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); |
f444c2c7 | 1455 | |
ab9152ff JH |
1456 | /* Remember headers block for signing (when the library cannot do incremental) */ |
1457 | (void) exim_rsa_data_append(&hdata, &hdata_alloc, rh); | |
3045f050 | 1458 | |
ab9152ff JH |
1459 | DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); |
1460 | } | |
8ef02a06 | 1461 | |
ca9cb170 | 1462 | l = sig->sign_headers; |
8ef02a06 JH |
1463 | while((s = string_nextinlist(&l, &sep, NULL, 0))) |
1464 | if (*s != '_') | |
ab9152ff | 1465 | { /*SSS string_append_listele() */ |
ca9cb170 | 1466 | if (hl > 0 && headernames[hl-1] != ':') |
c2f669a4 | 1467 | headernames = string_catn(headernames, &hs, &hl, US":", 1); |
ca9cb170 | 1468 | |
c2f669a4 | 1469 | headernames = string_cat(headernames, &hs, &hl, s); |
8ef02a06 | 1470 | } |
ca9cb170 JH |
1471 | headernames[hl] = '\0'; |
1472 | ||
1473 | /* Copy headernames to signature struct */ | |
1474 | sig->headernames = headernames; | |
ca9cb170 JH |
1475 | |
1476 | /* Create signature header with b= omitted */ | |
1477 | sig_hdr = pdkim_create_header(sig, FALSE); | |
80a47a2c | 1478 | } |
37f8b554 | 1479 | |
3045f050 JH |
1480 | /* VERIFICATION ----------------------------------------------------------- */ |
1481 | /* When verifying, walk through the header name list in the h= parameter and | |
1482 | add the headers to the hash in that order. */ | |
1483 | else | |
1484 | { | |
10c50704 | 1485 | uschar * p = sig->headernames; |
2592e6c0 JH |
1486 | uschar * q; |
1487 | pdkim_stringlist * hdrs; | |
3045f050 | 1488 | |
10c50704 | 1489 | if (p) |
3045f050 | 1490 | { |
10c50704 | 1491 | /* clear tags */ |
3045f050 | 1492 | for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) |
10c50704 | 1493 | hdrs->tag = 0; |
3045f050 | 1494 | |
10c50704 JH |
1495 | p = string_copy(p); |
1496 | while(1) | |
1497 | { | |
1498 | if ((q = Ustrchr(p, ':'))) | |
1499 | *q = '\0'; | |
1500 | ||
1501 | /*XXX walk the list of headers in same order as received. */ | |
1502 | for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) | |
1503 | if ( hdrs->tag == 0 | |
4dc2379a | 1504 | && strncasecmp(CCS hdrs->value, CCS p, Ustrlen(p)) == 0 |
10c50704 JH |
1505 | && (hdrs->value)[Ustrlen(p)] == ':' |
1506 | ) | |
1507 | { | |
1508 | /* cook header for relaxed canon, or just copy it for simple */ | |
1509 | ||
1510 | uschar * rh = sig->canon_headers == PDKIM_CANON_RELAXED | |
1511 | ? pdkim_relax_header(hdrs->value, 1) | |
1512 | : string_copy(CUS hdrs->value); | |
1513 | ||
1514 | /* Feed header to the hash algorithm */ | |
1515 | exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); | |
1516 | ||
1517 | DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); | |
1518 | hdrs->tag = 1; | |
1519 | break; | |
1520 | } | |
3045f050 | 1521 | |
10c50704 JH |
1522 | if (!q) break; |
1523 | p = q+1; | |
1524 | } | |
3045f050 | 1525 | |
10c50704 | 1526 | sig_hdr = string_copy(sig->rawsig_no_b_val); |
80a47a2c | 1527 | } |
80a47a2c TK |
1528 | } |
1529 | ||
0d04a285 | 1530 | DEBUG(D_acl) debug_printf( |
3045f050 | 1531 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
80a47a2c | 1532 | |
3045f050 JH |
1533 | /* Relax header if necessary */ |
1534 | if (sig->canon_headers == PDKIM_CANON_RELAXED) | |
ca9cb170 | 1535 | sig_hdr = pdkim_relax_header(sig_hdr, 0); |
80a47a2c | 1536 | |
0d04a285 | 1537 | DEBUG(D_acl) |
3045f050 | 1538 | { |
0d04a285 | 1539 | debug_printf( |
3045f050 | 1540 | "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n"); |
e2e3255a | 1541 | pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr)); |
0d04a285 | 1542 | debug_printf( |
3045f050 | 1543 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
80a47a2c | 1544 | } |
3045f050 JH |
1545 | |
1546 | /* Finalize header hash */ | |
e2e3255a | 1547 | exim_sha_update(&hhash_ctx, CUS sig_hdr, Ustrlen(sig_hdr)); |
2592e6c0 | 1548 | exim_sha_finish(&hhash_ctx, &hhash); |
3045f050 | 1549 | |
f444c2c7 JH |
1550 | DEBUG(D_acl) |
1551 | { | |
e21a4d00 | 1552 | debug_printf("PDKIM [%s] Header hash computed: ", sig->domain); |
2592e6c0 | 1553 | pdkim_hexprint(hhash.data, hhash.len); |
80a47a2c TK |
1554 | } |
1555 | ||
2592e6c0 | 1556 | /* Remember headers block for signing (when the library cannot do incremental) */ |
e983e85a | 1557 | if (ctx->flags & PDKIM_MODE_SIGN) |
b78006ac | 1558 | (void) exim_rsa_data_append(&hdata, &hdata_alloc, US sig_hdr); |
f444c2c7 | 1559 | |
3045f050 | 1560 | /* SIGNING ---------------------------------------------------------------- */ |
e983e85a | 1561 | if (ctx->flags & PDKIM_MODE_SIGN) |
3045f050 | 1562 | { |
2592e6c0 | 1563 | es_ctx sctx; |
f444c2c7 JH |
1564 | |
1565 | /* Import private key */ | |
b9df1829 | 1566 | if ((*err = exim_rsa_signing_init(US sig->rsa_privkey, &sctx))) |
f444c2c7 | 1567 | { |
b9df1829 | 1568 | DEBUG(D_acl) debug_printf("signing_init: %s\n", *err); |
f444c2c7 JH |
1569 | return PDKIM_ERR_RSA_PRIVKEY; |
1570 | } | |
80a47a2c | 1571 | |
2592e6c0 JH |
1572 | /* Do signing. With OpenSSL we are signing the hash of headers just |
1573 | calculated, with GnuTLS we have to sign an entire block of headers | |
1574 | (due to available interfaces) and it recalculates the hash internally. */ | |
f444c2c7 | 1575 | |
2592e6c0 JH |
1576 | #if defined(RSA_OPENSSL) || defined(RSA_GCRYPT) |
1577 | hdata = hhash; | |
f444c2c7 JH |
1578 | #endif |
1579 | ||
b9df1829 | 1580 | if ((*err = exim_rsa_sign(&sctx, is_sha1, &hdata, &sig->sighash))) |
f444c2c7 | 1581 | { |
b9df1829 | 1582 | DEBUG(D_acl) debug_printf("signing: %s\n", *err); |
f444c2c7 JH |
1583 | return PDKIM_ERR_RSA_SIGNING; |
1584 | } | |
80a47a2c | 1585 | |
0d04a285 | 1586 | DEBUG(D_acl) |
3045f050 | 1587 | { |
0d04a285 | 1588 | debug_printf( "PDKIM [%s] b computed: ", sig->domain); |
dcd03763 | 1589 | pdkim_hexprint(sig->sighash.data, sig->sighash.len); |
80a47a2c | 1590 | } |
80a47a2c | 1591 | |
ca9cb170 | 1592 | sig->signature_header = pdkim_create_header(sig, TRUE); |
80a47a2c | 1593 | } |
80a47a2c | 1594 | |
3045f050 JH |
1595 | /* VERIFICATION ----------------------------------------------------------- */ |
1596 | else | |
1597 | { | |
2592e6c0 | 1598 | ev_ctx vctx; |
3045f050 | 1599 | |
07eeb4df | 1600 | /* Make sure we have all required signature tags */ |
1601 | if (!( sig->domain && *sig->domain | |
1602 | && sig->selector && *sig->selector | |
1603 | && sig->headernames && *sig->headernames | |
1604 | && sig->bodyhash.data | |
dcd03763 | 1605 | && sig->sighash.data |
07eeb4df | 1606 | && sig->algo > -1 |
1607 | && sig->version | |
1608 | ) ) | |
1609 | { | |
1610 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1611 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR; | |
1612 | ||
1613 | DEBUG(D_acl) debug_printf( | |
1614 | " Error in DKIM-Signature header: tags missing or invalid\n" | |
1615 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); | |
1616 | goto NEXT_VERIFY; | |
1617 | } | |
1618 | ||
1619 | /* Make sure sig uses supported DKIM version (only v1) */ | |
1620 | if (sig->version != 1) | |
1621 | { | |
1622 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1623 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_DKIM_VERSION; | |
1624 | ||
1625 | DEBUG(D_acl) debug_printf( | |
1626 | " Error in DKIM-Signature header: unsupported DKIM version\n" | |
1627 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); | |
1628 | goto NEXT_VERIFY; | |
1629 | } | |
1630 | ||
b9df1829 | 1631 | if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx, err))) |
3045f050 | 1632 | goto NEXT_VERIFY; |
80a47a2c | 1633 | |
3045f050 | 1634 | /* Check the signature */ |
b9df1829 | 1635 | if ((*err = exim_rsa_verify(&vctx, is_sha1, &hhash, &sig->sighash))) |
3045f050 | 1636 | { |
b9df1829 | 1637 | DEBUG(D_acl) debug_printf("headers verify: %s\n", *err); |
3045f050 JH |
1638 | sig->verify_status = PDKIM_VERIFY_FAIL; |
1639 | sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE; | |
1640 | goto NEXT_VERIFY; | |
ff7ddfd7 TK |
1641 | } |
1642 | ||
2592e6c0 | 1643 | |
4c04137d | 1644 | /* We have a winner! (if bodyhash was correct earlier) */ |
3045f050 JH |
1645 | if (sig->verify_status == PDKIM_VERIFY_NONE) |
1646 | sig->verify_status = PDKIM_VERIFY_PASS; | |
1647 | ||
1648 | NEXT_VERIFY: | |
1649 | ||
0d04a285 | 1650 | DEBUG(D_acl) |
3045f050 | 1651 | { |
0d04a285 | 1652 | debug_printf("PDKIM [%s] signature status: %s", |
3045f050 JH |
1653 | sig->domain, pdkim_verify_status_str(sig->verify_status)); |
1654 | if (sig->verify_ext_status > 0) | |
0d04a285 | 1655 | debug_printf(" (%s)\n", |
3045f050 JH |
1656 | pdkim_verify_ext_status_str(sig->verify_ext_status)); |
1657 | else | |
0d04a285 | 1658 | debug_printf("\n"); |
80a47a2c | 1659 | } |
80a47a2c TK |
1660 | } |
1661 | ||
3045f050 | 1662 | sig = sig->next; |
80a47a2c TK |
1663 | } |
1664 | ||
3045f050 JH |
1665 | /* If requested, set return pointer to signature(s) */ |
1666 | if (return_signatures) | |
1667 | *return_signatures = ctx->sig; | |
80a47a2c | 1668 | |
3045f050 | 1669 | return PDKIM_OK; |
80a47a2c TK |
1670 | } |
1671 | ||
1672 | ||
1673 | /* -------------------------------------------------------------------------- */ | |
3045f050 JH |
1674 | |
1675 | DLLEXPORT pdkim_ctx * | |
e983e85a | 1676 | pdkim_init_verify(int(*dns_txt_callback)(char *, char *), BOOL dot_stuffing) |
3045f050 | 1677 | { |
ca9cb170 | 1678 | pdkim_ctx * ctx; |
3045f050 | 1679 | |
ca9cb170 | 1680 | ctx = store_get(sizeof(pdkim_ctx)); |
abe1010c | 1681 | memset(ctx, 0, sizeof(pdkim_ctx)); |
3045f050 | 1682 | |
e983e85a | 1683 | if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM; |
ca9cb170 | 1684 | ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN); |
3045f050 | 1685 | ctx->dns_txt_callback = dns_txt_callback; |
80a47a2c | 1686 | |
3045f050 | 1687 | return ctx; |
80a47a2c TK |
1688 | } |
1689 | ||
1690 | ||
1691 | /* -------------------------------------------------------------------------- */ | |
80a47a2c | 1692 | |
3045f050 | 1693 | DLLEXPORT pdkim_ctx * |
cd1a5fe0 | 1694 | pdkim_init_sign(char * domain, char * selector, char * rsa_privkey, int algo, |
b9df1829 JH |
1695 | BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *), |
1696 | const uschar ** errstr) | |
3045f050 | 1697 | { |
cd1a5fe0 JH |
1698 | pdkim_ctx * ctx; |
1699 | pdkim_signature * sig; | |
80a47a2c | 1700 | |
3045f050 JH |
1701 | if (!domain || !selector || !rsa_privkey) |
1702 | return NULL; | |
80a47a2c | 1703 | |
cd1a5fe0 | 1704 | ctx = store_get(sizeof(pdkim_ctx) + PDKIM_MAX_BODY_LINE_LEN + sizeof(pdkim_signature)); |
abe1010c | 1705 | memset(ctx, 0, sizeof(pdkim_ctx)); |
80a47a2c | 1706 | |
e983e85a | 1707 | ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN; |
cd1a5fe0 | 1708 | ctx->linebuf = CS (ctx+1); |
80a47a2c | 1709 | |
cd1a5fe0 JH |
1710 | DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback; |
1711 | ||
1712 | sig = (pdkim_signature *)(ctx->linebuf + PDKIM_MAX_BODY_LINE_LEN); | |
abe1010c | 1713 | memset(sig, 0, sizeof(pdkim_signature)); |
80a47a2c | 1714 | |
3045f050 | 1715 | sig->bodylength = -1; |
3045f050 | 1716 | ctx->sig = sig; |
80a47a2c | 1717 | |
e2e3255a JH |
1718 | sig->domain = string_copy(US domain); |
1719 | sig->selector = string_copy(US selector); | |
1720 | sig->rsa_privkey = string_copy(US rsa_privkey); | |
2592e6c0 | 1721 | sig->algo = algo; |
cb224393 | 1722 | |
7b83389d JH |
1723 | if (!exim_sha_init(&sig->body_hash_ctx, |
1724 | algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) | |
1725 | { | |
1726 | DEBUG(D_acl) debug_printf("PDKIM: hash setup internal error\n"); | |
1727 | return NULL; | |
1728 | } | |
1729 | ||
cd1a5fe0 JH |
1730 | DEBUG(D_acl) |
1731 | { | |
1732 | pdkim_signature s = *sig; | |
1733 | ev_ctx vctx; | |
1734 | ||
1735 | debug_printf("PDKIM (checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); | |
b9df1829 | 1736 | if (!pdkim_key_from_dns(ctx, &s, &vctx, errstr)) |
cd1a5fe0 JH |
1737 | debug_printf("WARNING: bad dkim key in dns\n"); |
1738 | debug_printf("PDKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); | |
1739 | } | |
3045f050 | 1740 | return ctx; |
6ab02e3f | 1741 | } |
80a47a2c | 1742 | |
f444c2c7 | 1743 | |
80a47a2c | 1744 | /* -------------------------------------------------------------------------- */ |
3045f050 JH |
1745 | |
1746 | DLLEXPORT int | |
1747 | pdkim_set_optional(pdkim_ctx *ctx, | |
80a47a2c TK |
1748 | char *sign_headers, |
1749 | char *identity, | |
1750 | int canon_headers, | |
1751 | int canon_body, | |
1752 | long bodylength, | |
80a47a2c | 1753 | unsigned long created, |
3045f050 JH |
1754 | unsigned long expires) |
1755 | { | |
8ef02a06 JH |
1756 | pdkim_signature * sig = ctx->sig; |
1757 | ||
3045f050 | 1758 | if (identity) |
e2e3255a | 1759 | sig->identity = string_copy(US identity); |
80a47a2c | 1760 | |
ca9cb170 JH |
1761 | sig->sign_headers = string_copy(sign_headers |
1762 | ? US sign_headers : US PDKIM_DEFAULT_SIGN_HEADERS); | |
80a47a2c | 1763 | |
8ef02a06 JH |
1764 | sig->canon_headers = canon_headers; |
1765 | sig->canon_body = canon_body; | |
1766 | sig->bodylength = bodylength; | |
1767 | sig->created = created; | |
1768 | sig->expires = expires; | |
80a47a2c | 1769 | |
3045f050 | 1770 | return PDKIM_OK; |
6ab02e3f | 1771 | } |
3045f050 | 1772 | |
3045f050 | 1773 | |
2592e6c0 JH |
1774 | void |
1775 | pdkim_init(void) | |
1776 | { | |
1777 | exim_rsa_init(); | |
1778 | } | |
1779 | ||
1780 | ||
1781 | ||
f444c2c7 | 1782 | #endif /*DISABLE_DKIM*/ |