Commit | Line | Data |
---|---|---|
80a47a2c TK |
1 | /* |
2 | * PDKIM - a RFC4871 (DKIM) implementation | |
3 | * | |
f444c2c7 | 4 | * Copyright (C) 2009 - 2016 Tom Kistner <tom@duncanthrax.net> |
1e1ddfac | 5 | * Copyright (C) 2016 - 2020 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 | ||
01603eec JH |
29 | #ifdef DISABLE_TLS |
30 | # error Must not DISABLE_TLS, for DKIM | |
f444c2c7 JH |
31 | #endif |
32 | ||
cb224393 | 33 | #include "crypt_ver.h" |
f444c2c7 | 34 | |
d73e45df | 35 | #ifdef SIGN_OPENSSL |
cb224393 JH |
36 | # include <openssl/rsa.h> |
37 | # include <openssl/ssl.h> | |
38 | # include <openssl/err.h> | |
d73e45df | 39 | #elif defined(SIGN_GNUTLS) |
f444c2c7 JH |
40 | # include <gnutls/gnutls.h> |
41 | # include <gnutls/x509.h> | |
f444c2c7 JH |
42 | #endif |
43 | ||
44 | #include "pdkim.h" | |
9b2583c4 | 45 | #include "signing.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 | |
80a47a2c TK |
54 | |
55 | /* -------------------------------------------------------------------------- */ | |
56 | struct pdkim_stringlist { | |
e2e3255a JH |
57 | uschar * value; |
58 | int tag; | |
59 | void * next; | |
80a47a2c TK |
60 | }; |
61 | ||
80a47a2c TK |
62 | /* -------------------------------------------------------------------------- */ |
63 | /* A bunch of list constants */ | |
e2e3255a JH |
64 | const uschar * pdkim_querymethods[] = { |
65 | US"dns/txt", | |
80a47a2c TK |
66 | NULL |
67 | }; | |
e2e3255a JH |
68 | const uschar * pdkim_canons[] = { |
69 | US"simple", | |
70 | US"relaxed", | |
80a47a2c TK |
71 | NULL |
72 | }; | |
d73e45df | 73 | |
617d3932 | 74 | const pdkim_hashtype pdkim_hashes[] = { |
d73e45df JH |
75 | { US"sha1", HASH_SHA1 }, |
76 | { US"sha256", HASH_SHA2_256 }, | |
77 | { US"sha512", HASH_SHA2_512 } | |
80a47a2c | 78 | }; |
d73e45df | 79 | |
e2e3255a | 80 | const uschar * pdkim_keytypes[] = { |
286b9d5f JH |
81 | [KEYTYPE_RSA] = US"rsa", |
82 | #ifdef SIGN_HAVE_ED25519 | |
321ef002 | 83 | [KEYTYPE_ED25519] = US"ed25519", /* Works for 3.6.0 GnuTLS, OpenSSL 1.1.1 */ |
286b9d5f JH |
84 | #endif |
85 | ||
86 | #ifdef notyet_EC_dkim_extensions /* https://tools.ietf.org/html/draft-srose-dkim-ecc-00 */ | |
87 | US"eccp256", | |
88 | US"eccp348", | |
89 | US"ed448", | |
90 | #endif | |
80a47a2c TK |
91 | }; |
92 | ||
93 | typedef struct pdkim_combined_canon_entry { | |
286b9d5f JH |
94 | const uschar * str; |
95 | int canon_headers; | |
96 | int canon_body; | |
80a47a2c | 97 | } pdkim_combined_canon_entry; |
f444c2c7 | 98 | |
80a47a2c | 99 | pdkim_combined_canon_entry pdkim_combined_canons[] = { |
e2e3255a JH |
100 | { US"simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, |
101 | { US"simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED }, | |
102 | { US"relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, | |
103 | { US"relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED }, | |
104 | { US"simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, | |
105 | { US"relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, | |
106 | { NULL, 0, 0 } | |
80a47a2c TK |
107 | }; |
108 | ||
109 | ||
9e70917d JH |
110 | static blob lineending = {.data = US"\r\n", .len = 2}; |
111 | ||
f444c2c7 | 112 | /* -------------------------------------------------------------------------- */ |
d73e45df | 113 | uschar * |
9e70917d | 114 | dkim_sig_to_a_tag(const pdkim_signature * sig) |
d73e45df JH |
115 | { |
116 | if ( sig->keytype < 0 || sig->keytype > nelem(pdkim_keytypes) | |
117 | || sig->hashtype < 0 || sig->hashtype > nelem(pdkim_hashes)) | |
118 | return US"err"; | |
119 | return string_sprintf("%s-%s", | |
120 | pdkim_keytypes[sig->keytype], pdkim_hashes[sig->hashtype].dkim_hashname); | |
121 | } | |
122 | ||
123 | ||
042e558f JH |
124 | static int |
125 | pdkim_keyname_to_keytype(const uschar * s) | |
126 | { | |
127 | for (int i = 0; i < nelem(pdkim_keytypes); i++) | |
128 | if (Ustrcmp(s, pdkim_keytypes[i]) == 0) return i; | |
129 | return -1; | |
130 | } | |
131 | ||
617d3932 JH |
132 | int |
133 | pdkim_hashname_to_hashtype(const uschar * s, unsigned len) | |
134 | { | |
617d3932 | 135 | if (!len) len = Ustrlen(s); |
d7978c0f | 136 | for (int i = 0; i < nelem(pdkim_hashes); i++) |
617d3932 JH |
137 | if (Ustrncmp(s, pdkim_hashes[i].dkim_hashname, len) == 0) |
138 | return i; | |
139 | return -1; | |
140 | } | |
141 | ||
142 | void | |
143 | pdkim_cstring_to_canons(const uschar * s, unsigned len, | |
144 | int * canon_head, int * canon_body) | |
145 | { | |
617d3932 | 146 | if (!len) len = Ustrlen(s); |
d7978c0f | 147 | for (int i = 0; pdkim_combined_canons[i].str; i++) |
617d3932 JH |
148 | if ( Ustrncmp(s, pdkim_combined_canons[i].str, len) == 0 |
149 | && len == Ustrlen(pdkim_combined_canons[i].str)) | |
150 | { | |
151 | *canon_head = pdkim_combined_canons[i].canon_headers; | |
152 | *canon_body = pdkim_combined_canons[i].canon_body; | |
153 | break; | |
154 | } | |
155 | } | |
156 | ||
157 | ||
f444c2c7 JH |
158 | |
159 | const char * | |
160 | pdkim_verify_status_str(int status) | |
161 | { | |
f7302073 JH |
162 | switch(status) |
163 | { | |
164 | case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE"; | |
165 | case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID"; | |
166 | case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL"; | |
167 | case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS"; | |
168 | default: return "PDKIM_VERIFY_UNKNOWN"; | |
ff7ddfd7 TK |
169 | } |
170 | } | |
f444c2c7 JH |
171 | |
172 | const char * | |
173 | pdkim_verify_ext_status_str(int ext_status) | |
174 | { | |
f7302073 JH |
175 | switch(ext_status) |
176 | { | |
177 | case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY"; | |
178 | case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE"; | |
135e9496 | 179 | case PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH: return "PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH"; |
f7302073 JH |
180 | case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE"; |
181 | case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE"; | |
182 | case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD"; | |
183 | case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT"; | |
be24b950 | 184 | case PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE: return "PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE"; |
f7302073 JH |
185 | case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: return "PDKIM_VERIFY_INVALID_SIGNATURE_ERROR"; |
186 | case PDKIM_VERIFY_INVALID_DKIM_VERSION: return "PDKIM_VERIFY_INVALID_DKIM_VERSION"; | |
187 | default: return "PDKIM_VERIFY_UNKNOWN"; | |
188 | } | |
189 | } | |
190 | ||
b9df1829 | 191 | const uschar * |
f7302073 JH |
192 | pdkim_errstr(int status) |
193 | { | |
194 | switch(status) | |
195 | { | |
b9df1829 JH |
196 | case PDKIM_OK: return US"OK"; |
197 | case PDKIM_FAIL: return US"FAIL"; | |
286b9d5f JH |
198 | case PDKIM_ERR_RSA_PRIVKEY: return US"PRIVKEY"; |
199 | case PDKIM_ERR_RSA_SIGNING: return US"SIGNING"; | |
200 | case PDKIM_ERR_LONG_LINE: return US"LONG_LINE"; | |
b9df1829 | 201 | case PDKIM_ERR_BUFFER_TOO_SMALL: return US"BUFFER_TOO_SMALL"; |
64b67b65 | 202 | case PDKIM_ERR_EXCESS_SIGS: return US"EXCESS_SIGS"; |
b9df1829 JH |
203 | case PDKIM_SIGN_PRIVKEY_WRAP: return US"PRIVKEY_WRAP"; |
204 | case PDKIM_SIGN_PRIVKEY_B64D: return US"PRIVKEY_B64D"; | |
ef698bf6 | 205 | default: return US"(unknown)"; |
ff7ddfd7 TK |
206 | } |
207 | } | |
208 | ||
209 | ||
80a47a2c TK |
210 | /* -------------------------------------------------------------------------- */ |
211 | /* Print debugging functions */ | |
617d3932 | 212 | void |
b78006ac | 213 | pdkim_quoteprint(const uschar *data, int len) |
3045f050 | 214 | { |
d7978c0f | 215 | for (int i = 0; i < len; i++) |
3045f050 | 216 | { |
b78006ac | 217 | const int c = data[i]; |
3045f050 JH |
218 | switch (c) |
219 | { | |
0d04a285 JH |
220 | case ' ' : debug_printf("{SP}"); break; |
221 | case '\t': debug_printf("{TB}"); break; | |
222 | case '\r': debug_printf("{CR}"); break; | |
223 | case '\n': debug_printf("{LF}"); break; | |
224 | case '{' : debug_printf("{BO}"); break; | |
225 | case '}' : debug_printf("{BC}"); break; | |
3045f050 JH |
226 | default: |
227 | if ( (c < 32) || (c > 127) ) | |
0d04a285 | 228 | debug_printf("{%02x}", c); |
3045f050 | 229 | else |
0d04a285 | 230 | debug_printf("%c", c); |
80a47a2c TK |
231 | break; |
232 | } | |
233 | } | |
2592e6c0 | 234 | debug_printf("\n"); |
80a47a2c | 235 | } |
80a47a2c | 236 | |
617d3932 | 237 | void |
b78006ac | 238 | pdkim_hexprint(const uschar *data, int len) |
3045f050 | 239 | { |
d7978c0f | 240 | if (data) for (int i = 0 ; i < len; i++) debug_printf("%02x", data[i]); |
02c4f8fb | 241 | else debug_printf("<NULL>"); |
2592e6c0 | 242 | debug_printf("\n"); |
80a47a2c | 243 | } |
80a47a2c TK |
244 | |
245 | ||
f444c2c7 | 246 | |
f444c2c7 | 247 | static pdkim_stringlist * |
ca9cb170 | 248 | pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str) |
3045f050 | 249 | { |
f3ebb786 | 250 | pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist), FALSE); |
3045f050 | 251 | |
abe1010c | 252 | memset(new_entry, 0, sizeof(pdkim_stringlist)); |
ca9cb170 | 253 | new_entry->value = string_copy(str); |
ab9152ff JH |
254 | if (base) new_entry->next = base; |
255 | return new_entry; | |
6ab02e3f | 256 | } |
80a47a2c TK |
257 | |
258 | ||
8ef02a06 JH |
259 | |
260 | /* Trim whitespace fore & aft */ | |
261 | ||
ca9cb170 | 262 | static void |
acec9514 | 263 | pdkim_strtrim(gstring * str) |
3045f050 | 264 | { |
acec9514 | 265 | uschar * p = str->s; |
b2bcdd35 | 266 | uschar * q; |
acec9514 JH |
267 | |
268 | while (*p == '\t' || *p == ' ') /* dump the leading whitespace */ | |
269 | { str->size--; str->ptr--; str->s++; } | |
270 | ||
271 | while ( str->ptr > 0 | |
81147e20 | 272 | && ((q = str->s + str->ptr - 1), (*q == '\t' || *q == ' ')) |
acec9514 JH |
273 | ) |
274 | str->ptr--; /* dump trailing whitespace */ | |
275 | ||
276 | (void) string_from_gstring(str); | |
8ef02a06 JH |
277 | } |
278 | ||
279 | ||
80a47a2c | 280 | |
80a47a2c | 281 | /* -------------------------------------------------------------------------- */ |
3045f050 JH |
282 | |
283 | DLLEXPORT void | |
284 | pdkim_free_ctx(pdkim_ctx *ctx) | |
285 | { | |
6ab02e3f | 286 | } |
80a47a2c TK |
287 | |
288 | ||
289 | /* -------------------------------------------------------------------------- */ | |
290 | /* Matches the name of the passed raw "header" against | |
8ef02a06 | 291 | the passed colon-separated "tick", and invalidates |
484cc1a9 JH |
292 | the entry in tick. Entries can be prefixed for multi- or over-signing, |
293 | in which case do not invalidate. | |
294 | ||
295 | Returns OK for a match, or fail-code | |
296 | */ | |
3045f050 | 297 | |
f444c2c7 | 298 | static int |
e2e3255a | 299 | header_name_match(const uschar * header, uschar * tick) |
3045f050 | 300 | { |
484cc1a9 JH |
301 | const uschar * ticklist = tick; |
302 | int sep = ':'; | |
303 | BOOL multisign; | |
304 | uschar * hname, * p, * ele; | |
ca9cb170 | 305 | uschar * hcolon = Ustrchr(header, ':'); /* Get header name */ |
3045f050 | 306 | |
ca9cb170 JH |
307 | if (!hcolon) |
308 | return PDKIM_FAIL; /* This isn't a header */ | |
3045f050 | 309 | |
ca9cb170 JH |
310 | /* if we had strncmpic() we wouldn't need this copy */ |
311 | hname = string_copyn(header, hcolon-header); | |
3045f050 | 312 | |
484cc1a9 | 313 | while (p = US ticklist, ele = string_nextinlist(&ticklist, &sep, NULL, 0)) |
3045f050 | 314 | { |
484cc1a9 JH |
315 | switch (*ele) |
316 | { | |
317 | case '=': case '+': multisign = TRUE; ele++; break; | |
318 | default: multisign = FALSE; break; | |
80a47a2c TK |
319 | } |
320 | ||
484cc1a9 JH |
321 | if (strcmpic(ele, hname) == 0) |
322 | { | |
323 | if (!multisign) | |
324 | *p = '_'; /* Invalidate this header name instance in tick-off list */ | |
325 | return PDKIM_OK; | |
326 | } | |
327 | } | |
ca9cb170 | 328 | return PDKIM_FAIL; |
80a47a2c TK |
329 | } |
330 | ||
331 | ||
332 | /* -------------------------------------------------------------------------- */ | |
ca9cb170 | 333 | /* Performs "relaxed" canonicalization of a header. */ |
3045f050 | 334 | |
617d3932 JH |
335 | uschar * |
336 | pdkim_relax_header_n(const uschar * header, int len, BOOL append_crlf) | |
3045f050 JH |
337 | { |
338 | BOOL past_field_name = FALSE; | |
339 | BOOL seen_wsp = FALSE; | |
f3ebb786 | 340 | uschar * relaxed = store_get(len+3, TRUE); /* tainted */ |
ca9cb170 | 341 | uschar * q = relaxed; |
3045f050 | 342 | |
d7978c0f | 343 | for (const uschar * p = header; p - header < len; p++) |
3045f050 | 344 | { |
ca9cb170 | 345 | uschar c = *p; |
ea18931d JH |
346 | |
347 | if (c == '\r' || c == '\n') /* Ignore CR & LF */ | |
3045f050 JH |
348 | continue; |
349 | if (c == '\t' || c == ' ') | |
350 | { | |
351 | if (seen_wsp) | |
80a47a2c | 352 | continue; |
3045f050 JH |
353 | c = ' '; /* Turns WSP into SP */ |
354 | seen_wsp = TRUE; | |
80a47a2c | 355 | } |
3045f050 JH |
356 | else |
357 | if (!past_field_name && c == ':') | |
358 | { | |
ea18931d JH |
359 | if (seen_wsp) q--; /* This removes WSP immediately before the colon */ |
360 | seen_wsp = TRUE; /* This removes WSP immediately after the colon */ | |
3045f050 | 361 | past_field_name = TRUE; |
80a47a2c | 362 | } |
3045f050 JH |
363 | else |
364 | seen_wsp = FALSE; | |
365 | ||
366 | /* Lowercase header name */ | |
367 | if (!past_field_name) c = tolower(c); | |
368 | *q++ = c; | |
80a47a2c | 369 | } |
3045f050 JH |
370 | |
371 | if (q > relaxed && q[-1] == ' ') q--; /* Squash eventual trailing SP */ | |
3045f050 | 372 | |
ea18931d | 373 | if (append_crlf) { *q++ = '\r'; *q++ = '\n'; } |
ca9cb170 | 374 | *q = '\0'; |
3045f050 | 375 | return relaxed; |
6ab02e3f | 376 | } |
80a47a2c TK |
377 | |
378 | ||
617d3932 JH |
379 | uschar * |
380 | pdkim_relax_header(const uschar * header, BOOL append_crlf) | |
381 | { | |
382 | return pdkim_relax_header_n(header, Ustrlen(header), append_crlf); | |
383 | } | |
384 | ||
385 | ||
80a47a2c TK |
386 | /* -------------------------------------------------------------------------- */ |
387 | #define PDKIM_QP_ERROR_DECODE -1 | |
3045f050 | 388 | |
35cf75e9 JH |
389 | static const uschar * |
390 | pdkim_decode_qp_char(const uschar *qp_p, int *c) | |
3045f050 | 391 | { |
35cf75e9 | 392 | const uschar *initial_pos = qp_p; |
3045f050 JH |
393 | |
394 | /* Advance one char */ | |
395 | qp_p++; | |
396 | ||
397 | /* Check for two hex digits and decode them */ | |
398 | if (isxdigit(*qp_p) && isxdigit(qp_p[1])) | |
399 | { | |
400 | /* Do hex conversion */ | |
401 | *c = (isdigit(*qp_p) ? *qp_p - '0' : toupper(*qp_p) - 'A' + 10) << 4; | |
a5840e10 | 402 | *c |= isdigit(qp_p[1]) ? qp_p[1] - '0' : toupper(qp_p[1]) - 'A' + 10; |
3045f050 | 403 | return qp_p + 2; |
6ab02e3f | 404 | } |
80a47a2c | 405 | |
3045f050 JH |
406 | /* Illegal char here */ |
407 | *c = PDKIM_QP_ERROR_DECODE; | |
408 | return initial_pos; | |
80a47a2c TK |
409 | } |
410 | ||
411 | ||
412 | /* -------------------------------------------------------------------------- */ | |
3045f050 | 413 | |
e2e3255a | 414 | static uschar * |
35cf75e9 | 415 | pdkim_decode_qp(const uschar * str) |
3045f050 JH |
416 | { |
417 | int nchar = 0; | |
ca9cb170 | 418 | uschar * q; |
35cf75e9 | 419 | const uschar * p = str; |
f3ebb786 | 420 | uschar * n = store_get(Ustrlen(str)+1, TRUE); |
3045f050 JH |
421 | |
422 | *n = '\0'; | |
423 | q = n; | |
ca9cb170 | 424 | while (*p) |
3045f050 JH |
425 | { |
426 | if (*p == '=') | |
427 | { | |
428 | p = pdkim_decode_qp_char(p, &nchar); | |
429 | if (nchar >= 0) | |
430 | { | |
431 | *q++ = nchar; | |
432 | continue; | |
80a47a2c TK |
433 | } |
434 | } | |
3045f050 JH |
435 | else |
436 | *q++ = *p; | |
437 | p++; | |
80a47a2c | 438 | } |
3045f050 JH |
439 | *q = '\0'; |
440 | return n; | |
80a47a2c TK |
441 | } |
442 | ||
443 | ||
444 | /* -------------------------------------------------------------------------- */ | |
3045f050 | 445 | |
617d3932 | 446 | void |
35cf75e9 | 447 | pdkim_decode_base64(const uschar * str, blob * b) |
3045f050 | 448 | { |
617d3932 | 449 | int dlen = b64decode(str, &b->data); |
2592e6c0 JH |
450 | if (dlen < 0) b->data = NULL; |
451 | b->len = dlen; | |
80a47a2c TK |
452 | } |
453 | ||
617d3932 | 454 | uschar * |
2592e6c0 | 455 | pdkim_encode_base64(blob * b) |
3045f050 | 456 | { |
1f20760b | 457 | return b64encode(CUS b->data, b->len); |
80a47a2c TK |
458 | } |
459 | ||
460 | ||
461 | /* -------------------------------------------------------------------------- */ | |
462 | #define PDKIM_HDR_LIMBO 0 | |
463 | #define PDKIM_HDR_TAG 1 | |
464 | #define PDKIM_HDR_VALUE 2 | |
3045f050 | 465 | |
f444c2c7 | 466 | static pdkim_signature * |
9e70917d | 467 | pdkim_parse_sig_header(pdkim_ctx * ctx, uschar * raw_hdr) |
3045f050 | 468 | { |
2c0f3ea1 | 469 | pdkim_signature * sig; |
d7978c0f | 470 | uschar *q; |
acec9514 JH |
471 | gstring * cur_tag = NULL; |
472 | gstring * cur_val = NULL; | |
3045f050 JH |
473 | BOOL past_hname = FALSE; |
474 | BOOL in_b_val = FALSE; | |
475 | int where = PDKIM_HDR_LIMBO; | |
3045f050 | 476 | |
f3ebb786 | 477 | sig = store_get(sizeof(pdkim_signature), FALSE); |
abe1010c | 478 | memset(sig, 0, sizeof(pdkim_signature)); |
3045f050 JH |
479 | sig->bodylength = -1; |
480 | ||
07eeb4df | 481 | /* Set so invalid/missing data error display is accurate */ |
07eeb4df | 482 | sig->version = 0; |
d73e45df JH |
483 | sig->keytype = -1; |
484 | sig->hashtype = -1; | |
07eeb4df | 485 | |
f3ebb786 | 486 | q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1, TRUE); /* tainted */ |
80a47a2c | 487 | |
d7978c0f | 488 | for (uschar * p = raw_hdr; ; p++) |
3045f050 JH |
489 | { |
490 | char c = *p; | |
80a47a2c | 491 | |
3045f050 JH |
492 | /* Ignore FWS */ |
493 | if (c == '\r' || c == '\n') | |
494 | goto NEXT_CHAR; | |
80a47a2c | 495 | |
3045f050 JH |
496 | /* Fast-forward through header name */ |
497 | if (!past_hname) | |
498 | { | |
499 | if (c == ':') past_hname = TRUE; | |
500 | goto NEXT_CHAR; | |
80a47a2c TK |
501 | } |
502 | ||
3045f050 JH |
503 | if (where == PDKIM_HDR_LIMBO) |
504 | { | |
505 | /* In limbo, just wait for a tag-char to appear */ | |
506 | if (!(c >= 'a' && c <= 'z')) | |
507 | goto NEXT_CHAR; | |
80a47a2c | 508 | |
3045f050 | 509 | where = PDKIM_HDR_TAG; |
80a47a2c TK |
510 | } |
511 | ||
3045f050 JH |
512 | if (where == PDKIM_HDR_TAG) |
513 | { | |
3045f050 | 514 | if (c >= 'a' && c <= 'z') |
acec9514 | 515 | cur_tag = string_catn(cur_tag, p, 1); |
80a47a2c | 516 | |
3045f050 JH |
517 | if (c == '=') |
518 | { | |
acec9514 | 519 | if (Ustrcmp(string_from_gstring(cur_tag), "b") == 0) |
3045f050 | 520 | { |
ca9cb170 | 521 | *q++ = '='; |
3045f050 JH |
522 | in_b_val = TRUE; |
523 | } | |
524 | where = PDKIM_HDR_VALUE; | |
525 | goto NEXT_CHAR; | |
80a47a2c TK |
526 | } |
527 | } | |
528 | ||
3045f050 JH |
529 | if (where == PDKIM_HDR_VALUE) |
530 | { | |
3045f050 JH |
531 | if (c == '\r' || c == '\n' || c == ' ' || c == '\t') |
532 | goto NEXT_CHAR; | |
533 | ||
534 | if (c == ';' || c == '\0') | |
535 | { | |
a05d3e34 JH |
536 | /* We must have both tag and value, and tags must be one char except |
537 | for the possibility of "bh". */ | |
538 | ||
539 | if ( cur_tag && cur_val | |
540 | && (cur_tag->ptr == 1 || *cur_tag->s == 'b') | |
541 | ) | |
3045f050 | 542 | { |
acec9514 | 543 | (void) string_from_gstring(cur_val); |
3045f050 JH |
544 | pdkim_strtrim(cur_val); |
545 | ||
acec9514 | 546 | DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag->s, cur_val->s); |
3045f050 | 547 | |
acec9514 | 548 | switch (*cur_tag->s) |
3045f050 | 549 | { |
286b9d5f | 550 | case 'b': /* sig-data or body-hash */ |
a05d3e34 JH |
551 | switch (cur_tag->s[1]) |
552 | { | |
553 | case '\0': pdkim_decode_base64(cur_val->s, &sig->sighash); break; | |
554 | case 'h': if (cur_tag->ptr == 2) | |
555 | pdkim_decode_base64(cur_val->s, &sig->bodyhash); | |
556 | break; | |
557 | default: break; | |
558 | } | |
3045f050 | 559 | break; |
286b9d5f | 560 | case 'v': /* version */ |
3045f050 JH |
561 | /* We only support version 1, and that is currently the |
562 | only version there is. */ | |
07eeb4df | 563 | sig->version = |
acec9514 | 564 | Ustrcmp(cur_val->s, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1; |
3045f050 | 565 | break; |
286b9d5f | 566 | case 'a': /* algorithm */ |
d73e45df | 567 | { |
e220ba1d JH |
568 | const uschar * list = cur_val->s; |
569 | int sep = '-'; | |
570 | uschar * elem; | |
571 | ||
572 | if ((elem = string_nextinlist(&list, &sep, NULL, 0))) | |
042e558f | 573 | sig->keytype = pdkim_keyname_to_keytype(elem); |
e220ba1d | 574 | if ((elem = string_nextinlist(&list, &sep, NULL, 0))) |
d7978c0f | 575 | for (int i = 0; i < nelem(pdkim_hashes); i++) |
e220ba1d JH |
576 | if (Ustrcmp(elem, pdkim_hashes[i].dkim_hashname) == 0) |
577 | { sig->hashtype = i; break; } | |
d73e45df JH |
578 | } |
579 | ||
286b9d5f | 580 | case 'c': /* canonicalization */ |
617d3932 JH |
581 | pdkim_cstring_to_canons(cur_val->s, 0, |
582 | &sig->canon_headers, &sig->canon_body); | |
3045f050 | 583 | break; |
286b9d5f | 584 | case 'q': /* Query method (for pubkey)*/ |
d7978c0f | 585 | for (int i = 0; pdkim_querymethods[i]; i++) |
acec9514 | 586 | if (Ustrcmp(cur_val->s, pdkim_querymethods[i]) == 0) |
3045f050 | 587 | { |
286b9d5f | 588 | sig->querymethod = i; /* we never actually use this */ |
3045f050 JH |
589 | break; |
590 | } | |
591 | break; | |
286b9d5f | 592 | case 's': /* Selector */ |
acec9514 | 593 | sig->selector = string_copyn(cur_val->s, cur_val->ptr); break; |
286b9d5f | 594 | case 'd': /* SDID */ |
acec9514 | 595 | sig->domain = string_copyn(cur_val->s, cur_val->ptr); break; |
286b9d5f | 596 | case 'i': /* AUID */ |
acec9514 | 597 | sig->identity = pdkim_decode_qp(cur_val->s); break; |
286b9d5f | 598 | case 't': /* Timestamp */ |
acec9514 | 599 | sig->created = strtoul(CS cur_val->s, NULL, 10); break; |
286b9d5f | 600 | case 'x': /* Expiration */ |
acec9514 | 601 | sig->expires = strtoul(CS cur_val->s, NULL, 10); break; |
286b9d5f | 602 | case 'l': /* Body length count */ |
acec9514 | 603 | sig->bodylength = strtol(CS cur_val->s, NULL, 10); break; |
286b9d5f | 604 | case 'h': /* signed header fields */ |
acec9514 | 605 | sig->headernames = string_copyn(cur_val->s, cur_val->ptr); break; |
286b9d5f | 606 | case 'z': /* Copied headfields */ |
acec9514 | 607 | sig->copiedheaders = pdkim_decode_qp(cur_val->s); break; |
286b9d5f JH |
608 | /*XXX draft-ietf-dcrup-dkim-crypto-05 would need 'p' tag support |
609 | for rsafp signatures. But later discussion is dropping those. */ | |
3045f050 | 610 | default: |
0d04a285 | 611 | DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); |
3045f050 JH |
612 | break; |
613 | } | |
614 | } | |
acec9514 | 615 | cur_tag = cur_val = NULL; |
3045f050 JH |
616 | in_b_val = FALSE; |
617 | where = PDKIM_HDR_LIMBO; | |
80a47a2c | 618 | } |
3045f050 | 619 | else |
acec9514 | 620 | cur_val = string_catn(cur_val, p, 1); |
80a47a2c TK |
621 | } |
622 | ||
3045f050 JH |
623 | NEXT_CHAR: |
624 | if (c == '\0') | |
625 | break; | |
80a47a2c | 626 | |
3045f050 JH |
627 | if (!in_b_val) |
628 | *q++ = c; | |
80a47a2c TK |
629 | } |
630 | ||
286b9d5f JH |
631 | if (sig->keytype < 0 || sig->hashtype < 0) /* Cannot verify this signature */ |
632 | return NULL; | |
633 | ||
3045f050 JH |
634 | *q = '\0'; |
635 | /* Chomp raw header. The final newline must not be added to the signature. */ | |
37f3dc43 JH |
636 | while (--q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n')) |
637 | *q = '\0'; | |
80a47a2c | 638 | |
0d04a285 | 639 | DEBUG(D_acl) |
3045f050 | 640 | { |
0d04a285 | 641 | debug_printf( |
305f8921 | 642 | "DKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
e2e3255a | 643 | pdkim_quoteprint(US sig->rawsig_no_b_val, Ustrlen(sig->rawsig_no_b_val)); |
0d04a285 | 644 | debug_printf( |
305f8921 | 645 | "DKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8); |
0d04a285 | 646 | debug_printf( |
305f8921 | 647 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
80a47a2c | 648 | } |
80a47a2c | 649 | |
617d3932 | 650 | if (!pdkim_set_sig_bodyhash(ctx, sig)) |
7b83389d | 651 | return NULL; |
cf1cce5e | 652 | |
3045f050 | 653 | return sig; |
80a47a2c TK |
654 | } |
655 | ||
656 | ||
657 | /* -------------------------------------------------------------------------- */ | |
80a47a2c | 658 | |
617d3932 JH |
659 | pdkim_pubkey * |
660 | pdkim_parse_pubkey_record(const uschar *raw_record) | |
3045f050 | 661 | { |
35cf75e9 JH |
662 | const uschar * ele; |
663 | int sep = ';'; | |
664 | pdkim_pubkey * pub; | |
80a47a2c | 665 | |
f3ebb786 | 666 | pub = store_get(sizeof(pdkim_pubkey), TRUE); /* tainted */ |
abe1010c | 667 | memset(pub, 0, sizeof(pdkim_pubkey)); |
80a47a2c | 668 | |
35cf75e9 JH |
669 | while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0))) |
670 | { | |
671 | const uschar * val; | |
672 | ||
673 | if ((val = Ustrchr(ele, '='))) | |
3045f050 | 674 | { |
35cf75e9 | 675 | int taglen = val++ - ele; |
80a47a2c | 676 | |
35cf75e9 JH |
677 | DEBUG(D_acl) debug_printf(" %.*s=%s\n", taglen, ele, val); |
678 | switch (ele[0]) | |
3045f050 | 679 | { |
35cf75e9 JH |
680 | case 'v': pub->version = val; break; |
681 | case 'h': pub->hashes = val; break; | |
286b9d5f | 682 | case 'k': pub->keytype = val; break; |
35cf75e9 JH |
683 | case 'g': pub->granularity = val; break; |
684 | case 'n': pub->notes = pdkim_decode_qp(val); break; | |
685 | case 'p': pdkim_decode_base64(val, &pub->key); break; | |
686 | case 's': pub->srvtype = val; break; | |
687 | case 't': if (Ustrchr(val, 'y')) pub->testing = 1; | |
688 | if (Ustrchr(val, 's')) pub->no_subdomaining = 1; | |
e21a4d00 | 689 | break; |
35cf75e9 | 690 | default: DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); break; |
80a47a2c | 691 | } |
e21a4d00 | 692 | } |
35cf75e9 | 693 | } |
80a47a2c | 694 | |
3045f050 | 695 | /* Set fallback defaults */ |
fc6fb551 JH |
696 | if (!pub->version) |
697 | pub->version = string_copy(PDKIM_PUB_RECORD_VERSION); | |
135e9496 JH |
698 | else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0) |
699 | { | |
700 | DEBUG(D_acl) debug_printf(" Bad v= field\n"); | |
701 | return NULL; | |
702 | } | |
e21a4d00 | 703 | |
35cf75e9 | 704 | if (!pub->granularity) pub->granularity = US"*"; |
35cf75e9 | 705 | if (!pub->keytype ) pub->keytype = US"rsa"; |
35cf75e9 | 706 | if (!pub->srvtype ) pub->srvtype = US"*"; |
80a47a2c | 707 | |
3045f050 | 708 | /* p= is required */ |
2592e6c0 | 709 | if (pub->key.data) |
80a47a2c | 710 | return pub; |
3045f050 | 711 | |
135e9496 | 712 | DEBUG(D_acl) debug_printf(" Missing p= field\n"); |
3045f050 | 713 | return NULL; |
80a47a2c TK |
714 | } |
715 | ||
716 | ||
717 | /* -------------------------------------------------------------------------- */ | |
3045f050 | 718 | |
cf1cce5e | 719 | /* Update one bodyhash with some additional data. |
9e70917d JH |
720 | If we have to relax the data for this sig, return our copy of it. */ |
721 | ||
9e70917d | 722 | static blob * |
cf1cce5e | 723 | pdkim_update_ctx_bodyhash(pdkim_bodyhash * b, blob * orig_data, blob * relaxed_data) |
3045f050 | 724 | { |
9e70917d JH |
725 | blob * canon_data = orig_data; |
726 | /* Defaults to simple canon (no further treatment necessary) */ | |
3045f050 | 727 | |
cf1cce5e | 728 | if (b->canon_method == PDKIM_CANON_RELAXED) |
3045f050 | 729 | { |
9e70917d JH |
730 | /* Relax the line if not done already */ |
731 | if (!relaxed_data) | |
3045f050 | 732 | { |
9e70917d | 733 | BOOL seen_wsp = FALSE; |
9e70917d | 734 | int q = 0; |
3045f050 | 735 | |
9e70917d JH |
736 | /* We want to be able to free this else we allocate |
737 | for the entire message which could be many MB. Since | |
738 | we don't know what allocations the SHA routines might | |
739 | do, not safe to use store_get()/store_reset(). */ | |
d5bccfc8 | 740 | |
9e70917d JH |
741 | relaxed_data = store_malloc(sizeof(blob) + orig_data->len+1); |
742 | relaxed_data->data = US (relaxed_data+1); | |
3045f050 | 743 | |
d7978c0f | 744 | for (const uschar * p = orig_data->data, * r = p + orig_data->len; p < r; p++) |
9e70917d JH |
745 | { |
746 | char c = *p; | |
747 | if (c == '\r') | |
748 | { | |
749 | if (q > 0 && relaxed_data->data[q-1] == ' ') | |
750 | q--; | |
751 | } | |
752 | else if (c == '\t' || c == ' ') | |
753 | { | |
754 | c = ' '; /* Turns WSP into SP */ | |
755 | if (seen_wsp) | |
756 | continue; | |
757 | seen_wsp = TRUE; | |
3045f050 | 758 | } |
9e70917d JH |
759 | else |
760 | seen_wsp = FALSE; | |
761 | relaxed_data->data[q++] = c; | |
80a47a2c | 762 | } |
9e70917d JH |
763 | relaxed_data->data[q] = '\0'; |
764 | relaxed_data->len = q; | |
80a47a2c | 765 | } |
9e70917d JH |
766 | canon_data = relaxed_data; |
767 | } | |
80a47a2c | 768 | |
9e70917d | 769 | /* Make sure we don't exceed the to-be-signed body length */ |
cf1cce5e JH |
770 | if ( b->bodylength >= 0 |
771 | && b->signed_body_bytes + (unsigned long)canon_data->len > b->bodylength | |
9e70917d | 772 | ) |
cf1cce5e | 773 | canon_data->len = b->bodylength - b->signed_body_bytes; |
80a47a2c | 774 | |
9e70917d JH |
775 | if (canon_data->len > 0) |
776 | { | |
cf1cce5e JH |
777 | exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, canon_data->len); |
778 | b->signed_body_bytes += canon_data->len; | |
9e70917d | 779 | DEBUG(D_acl) pdkim_quoteprint(canon_data->data, canon_data->len); |
80a47a2c TK |
780 | } |
781 | ||
9e70917d | 782 | return relaxed_data; |
6ab02e3f | 783 | } |
80a47a2c TK |
784 | |
785 | ||
786 | /* -------------------------------------------------------------------------- */ | |
80a47a2c | 787 | |
ca9cb170 | 788 | static void |
9e70917d | 789 | pdkim_finish_bodyhash(pdkim_ctx * ctx) |
3045f050 | 790 | { |
d7978c0f | 791 | for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next) /* Finish hashes */ |
617d3932 | 792 | { |
305f8921 | 793 | DEBUG(D_acl) debug_printf("DKIM: finish bodyhash %d/%d/%ld len %ld\n", |
617d3932 | 794 | b->hashtype, b->canon_method, b->bodylength, b->signed_body_bytes); |
cf1cce5e | 795 | exim_sha_finish(&b->body_hash_ctx, &b->bh); |
617d3932 | 796 | } |
cf1cce5e | 797 | |
3045f050 | 798 | /* Traverse all signatures */ |
d7978c0f | 799 | for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next) |
cf1cce5e | 800 | { |
d7978c0f | 801 | pdkim_bodyhash * b = sig->calc_body_hash; |
3045f050 | 802 | |
0d04a285 | 803 | DEBUG(D_acl) |
3045f050 | 804 | { |
305f8921 HSHR |
805 | debug_printf("DKIM [%s] Body bytes (%s) hashed: %lu\n" |
806 | "DKIM [%s] Body %s computed: ", | |
4ff848b5 JH |
807 | sig->domain, pdkim_canons[b->canon_method], b->signed_body_bytes, |
808 | sig->domain, pdkim_hashes[b->hashtype].dkim_hashname); | |
cf1cce5e | 809 | pdkim_hexprint(CUS b->bh.data, b->bh.len); |
80a47a2c | 810 | } |
3045f050 JH |
811 | |
812 | /* SIGNING -------------------------------------------------------------- */ | |
e983e85a | 813 | if (ctx->flags & PDKIM_MODE_SIGN) |
3045f050 | 814 | { |
3045f050 JH |
815 | /* If bodylength limit is set, and we have received less bytes |
816 | than the requested amount, effectively remove the limit tag. */ | |
cf1cce5e | 817 | if (b->signed_body_bytes < sig->bodylength) |
3045f050 | 818 | sig->bodylength = -1; |
80a47a2c | 819 | } |
3045f050 | 820 | |
3045f050 | 821 | else |
02c4f8fb JH |
822 | /* VERIFICATION --------------------------------------------------------- */ |
823 | /* Be careful that the header sig included a bodyash */ | |
824 | ||
cf1cce5e JH |
825 | if ( sig->bodyhash.data |
826 | && memcmp(b->bh.data, sig->bodyhash.data, b->bh.len) == 0) | |
3045f050 | 827 | { |
305f8921 | 828 | DEBUG(D_acl) debug_printf("DKIM [%s] Body hash compared OK\n", sig->domain); |
80a47a2c | 829 | } |
3045f050 JH |
830 | else |
831 | { | |
0d04a285 | 832 | DEBUG(D_acl) |
3045f050 | 833 | { |
305f8921 | 834 | debug_printf("DKIM [%s] Body hash signature from headers: ", sig->domain); |
dcd03763 | 835 | pdkim_hexprint(sig->bodyhash.data, sig->bodyhash.len); |
305f8921 | 836 | debug_printf("DKIM [%s] Body hash did NOT verify\n", sig->domain); |
3045f050 | 837 | } |
3045f050 JH |
838 | sig->verify_status = PDKIM_VERIFY_FAIL; |
839 | sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY; | |
80a47a2c | 840 | } |
80a47a2c | 841 | } |
6ab02e3f | 842 | } |
80a47a2c TK |
843 | |
844 | ||
845 | ||
9e70917d | 846 | static void |
e983e85a JH |
847 | pdkim_body_complete(pdkim_ctx * ctx) |
848 | { | |
e983e85a JH |
849 | /* In simple body mode, if any empty lines were buffered, |
850 | replace with one. rfc 4871 3.4.3 */ | |
851 | /*XXX checking the signed-body-bytes is a gross hack; I think | |
852 | it indicates that all linebreaks should be buffered, including | |
853 | the one terminating a text line */ | |
854 | ||
d7978c0f | 855 | for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next) |
cf1cce5e JH |
856 | if ( b->canon_method == PDKIM_CANON_SIMPLE |
857 | && b->signed_body_bytes == 0 | |
858 | && b->num_buffered_blanklines > 0 | |
9e70917d | 859 | ) |
cf1cce5e | 860 | (void) pdkim_update_ctx_bodyhash(b, &lineending, NULL); |
e983e85a JH |
861 | |
862 | ctx->flags |= PDKIM_SEEN_EOD; | |
863 | ctx->linebuf_offset = 0; | |
e983e85a JH |
864 | } |
865 | ||
866 | ||
867 | ||
80a47a2c | 868 | /* -------------------------------------------------------------------------- */ |
e983e85a | 869 | /* Call from pdkim_feed below for processing complete body lines */ |
744976d4 | 870 | /* NOTE: the line is not NUL-terminated; but we have a count */ |
3045f050 | 871 | |
9e70917d JH |
872 | static void |
873 | pdkim_bodyline_complete(pdkim_ctx * ctx) | |
3045f050 | 874 | { |
9e70917d | 875 | blob line = {.data = ctx->linebuf, .len = ctx->linebuf_offset}; |
9e70917d JH |
876 | blob * rnl = NULL; |
877 | blob * rline = NULL; | |
3045f050 JH |
878 | |
879 | /* Ignore extra data if we've seen the end-of-data marker */ | |
9e70917d | 880 | if (ctx->flags & PDKIM_SEEN_EOD) goto all_skip; |
3045f050 JH |
881 | |
882 | /* We've always got one extra byte to stuff a zero ... */ | |
9e70917d | 883 | ctx->linebuf[line.len] = '\0'; |
3045f050 | 884 | |
0d04a285 | 885 | /* Terminate on EOD marker */ |
e983e85a | 886 | if (ctx->flags & PDKIM_DOT_TERM) |
3045f050 | 887 | { |
9e70917d JH |
888 | if (memcmp(line.data, ".\r\n", 3) == 0) |
889 | { pdkim_body_complete(ctx); return; } | |
0d04a285 | 890 | |
e983e85a | 891 | /* Unstuff dots */ |
9e70917d JH |
892 | if (memcmp(line.data, "..", 2) == 0) |
893 | { line.data++; line.len--; } | |
80a47a2c TK |
894 | } |
895 | ||
3045f050 | 896 | /* Empty lines need to be buffered until we find a non-empty line */ |
9e70917d | 897 | if (memcmp(line.data, "\r\n", 2) == 0) |
3045f050 | 898 | { |
d7978c0f JH |
899 | for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next) |
900 | b->num_buffered_blanklines++; | |
9e70917d | 901 | goto all_skip; |
80a47a2c TK |
902 | } |
903 | ||
cf1cce5e | 904 | /* Process line for each bodyhash separately */ |
d7978c0f | 905 | for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next) |
3045f050 | 906 | { |
cf1cce5e | 907 | if (b->canon_method == PDKIM_CANON_RELAXED) |
3045f050 | 908 | { |
9e70917d | 909 | /* Lines with just spaces need to be buffered too */ |
7845dbb3 | 910 | uschar * cp = line.data; |
9e70917d | 911 | char c; |
6a11a9e6 | 912 | |
9e70917d JH |
913 | while ((c = *cp)) |
914 | { | |
915 | if (c == '\r' && cp[1] == '\n') break; | |
cf1cce5e | 916 | if (c != ' ' && c != '\t') goto hash_process; |
9e70917d JH |
917 | cp++; |
918 | } | |
919 | ||
cf1cce5e JH |
920 | b->num_buffered_blanklines++; |
921 | goto hash_skip; | |
6a11a9e6 JH |
922 | } |
923 | ||
cf1cce5e | 924 | hash_process: |
9e70917d | 925 | /* At this point, we have a non-empty line, so release the buffered ones. */ |
6a11a9e6 | 926 | |
cf1cce5e | 927 | while (b->num_buffered_blanklines) |
9e70917d | 928 | { |
cf1cce5e JH |
929 | rnl = pdkim_update_ctx_bodyhash(b, &lineending, rnl); |
930 | b->num_buffered_blanklines--; | |
9e70917d JH |
931 | } |
932 | ||
cf1cce5e JH |
933 | rline = pdkim_update_ctx_bodyhash(b, &line, rline); |
934 | hash_skip: ; | |
80a47a2c TK |
935 | } |
936 | ||
9e70917d JH |
937 | if (rnl) store_free(rnl); |
938 | if (rline) store_free(rline); | |
939 | ||
940 | all_skip: | |
80a47a2c | 941 | |
3045f050 | 942 | ctx->linebuf_offset = 0; |
9e70917d | 943 | return; |
80a47a2c TK |
944 | } |
945 | ||
946 | ||
947 | /* -------------------------------------------------------------------------- */ | |
948 | /* Callback from pdkim_feed below for processing complete headers */ | |
949 | #define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:" | |
3045f050 | 950 | |
f444c2c7 | 951 | static int |
2c0f3ea1 | 952 | pdkim_header_complete(pdkim_ctx * ctx) |
3045f050 | 953 | { |
acec9514 JH |
954 | if ( (ctx->cur_header->ptr > 1) && |
955 | (ctx->cur_header->s[ctx->cur_header->ptr-1] == '\r') ) | |
956 | --ctx->cur_header->ptr; | |
957 | (void) string_from_gstring(ctx->cur_header); | |
80a47a2c | 958 | |
617d3932 JH |
959 | #ifdef EXPERIMENTAL_ARC |
960 | /* Feed the header line to ARC processing */ | |
961 | (void) arc_header_feed(ctx->cur_header, !(ctx->flags & PDKIM_MODE_SIGN)); | |
962 | #endif | |
963 | ||
2c0f3ea1 | 964 | if (++ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL; |
80a47a2c | 965 | |
3045f050 | 966 | /* SIGNING -------------------------------------------------------------- */ |
e983e85a | 967 | if (ctx->flags & PDKIM_MODE_SIGN) |
d7978c0f | 968 | for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */ |
80a47a2c | 969 | |
ab9152ff | 970 | /* Add header to the signed headers list (in reverse order) */ |
acec9514 | 971 | sig->headers = pdkim_prepend_stringlist(sig->headers, ctx->cur_header->s); |
94431adb | 972 | |
0d04a285 | 973 | /* VERIFICATION ----------------------------------------------------------- */ |
3045f050 | 974 | /* DKIM-Signature: headers are added to the verification list */ |
e983e85a | 975 | else |
3045f050 | 976 | { |
f6ee24a2 | 977 | #ifdef notdef |
bd8fbe36 JH |
978 | DEBUG(D_acl) |
979 | { | |
305f8921 | 980 | debug_printf("DKIM >> raw hdr: "); |
acec9514 | 981 | pdkim_quoteprint(CUS ctx->cur_header->s, ctx->cur_header->ptr); |
bd8fbe36 | 982 | } |
f6ee24a2 | 983 | #endif |
acec9514 | 984 | if (strncasecmp(CCS ctx->cur_header->s, |
3045f050 | 985 | DKIM_SIGNATURE_HEADERNAME, |
e2e3255a | 986 | Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0) |
3045f050 | 987 | { |
d7978c0f | 988 | pdkim_signature * sig, * last_sig; |
02c4f8fb JH |
989 | /* Create and chain new signature block. We could error-check for all |
990 | required tags here, but prefer to create the internal sig and expicitly | |
991 | fail verification of it later. */ | |
80a47a2c | 992 | |
0d04a285 | 993 | DEBUG(D_acl) debug_printf( |
305f8921 | 994 | "DKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
3045f050 | 995 | |
acec9514 | 996 | sig = pdkim_parse_sig_header(ctx, ctx->cur_header->s); |
02c4f8fb JH |
997 | |
998 | if (!(last_sig = ctx->sig)) | |
2c0f3ea1 | 999 | ctx->sig = sig; |
02c4f8fb | 1000 | else |
3045f050 | 1001 | { |
02c4f8fb | 1002 | while (last_sig->next) last_sig = last_sig->next; |
2c0f3ea1 | 1003 | last_sig->next = sig; |
80a47a2c | 1004 | } |
64b67b65 JH |
1005 | |
1006 | if (--dkim_collect_input == 0) | |
1007 | { | |
1008 | ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s); | |
1009 | ctx->cur_header->s[ctx->cur_header->ptr = 0] = '\0'; | |
1010 | return PDKIM_ERR_EXCESS_SIGS; | |
1011 | } | |
80a47a2c | 1012 | } |
37f8b554 | 1013 | |
eea19017 | 1014 | /* all headers are stored for signature verification */ |
acec9514 | 1015 | ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s); |
80a47a2c TK |
1016 | } |
1017 | ||
3045f050 | 1018 | BAIL: |
acec9514 | 1019 | ctx->cur_header->s[ctx->cur_header->ptr = 0] = '\0'; /* leave buffer for reuse */ |
3045f050 | 1020 | return PDKIM_OK; |
6ab02e3f | 1021 | } |
80a47a2c TK |
1022 | |
1023 | ||
1024 | ||
1025 | /* -------------------------------------------------------------------------- */ | |
1026 | #define HEADER_BUFFER_FRAG_SIZE 256 | |
3045f050 JH |
1027 | |
1028 | DLLEXPORT int | |
ef698bf6 | 1029 | pdkim_feed(pdkim_ctx * ctx, uschar * data, int len) |
3045f050 | 1030 | { |
e983e85a JH |
1031 | /* Alternate EOD signal, used in non-dotstuffing mode */ |
1032 | if (!data) | |
1033 | pdkim_body_complete(ctx); | |
1034 | ||
d7978c0f | 1035 | else for (int p = 0; p < len; p++) |
3045f050 | 1036 | { |
ca9cb170 | 1037 | uschar c = data[p]; |
d7978c0f | 1038 | int rc; |
3045f050 | 1039 | |
e983e85a | 1040 | if (ctx->flags & PDKIM_PAST_HDRS) |
3045f050 | 1041 | { |
b895f4b2 JH |
1042 | if (c == '\n' && !(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ |
1043 | { | |
1044 | ctx->linebuf[ctx->linebuf_offset++] = '\r'; | |
1045 | if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) | |
1046 | return PDKIM_ERR_LONG_LINE; | |
1047 | } | |
1048 | ||
3045f050 | 1049 | /* Processing body byte */ |
0d04a285 | 1050 | ctx->linebuf[ctx->linebuf_offset++] = c; |
b895f4b2 JH |
1051 | if (c == '\r') |
1052 | ctx->flags |= PDKIM_SEEN_CR; | |
1053 | else if (c == '\n') | |
3045f050 | 1054 | { |
b895f4b2 | 1055 | ctx->flags &= ~PDKIM_SEEN_CR; |
9e70917d | 1056 | pdkim_bodyline_complete(ctx); |
80a47a2c | 1057 | } |
b895f4b2 JH |
1058 | |
1059 | if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) | |
3045f050 | 1060 | return PDKIM_ERR_LONG_LINE; |
80a47a2c | 1061 | } |
3045f050 JH |
1062 | else |
1063 | { | |
1064 | /* Processing header byte */ | |
b895f4b2 JH |
1065 | if (c == '\r') |
1066 | ctx->flags |= PDKIM_SEEN_CR; | |
1067 | else if (c == '\n') | |
3045f050 | 1068 | { |
b895f4b2 | 1069 | if (!(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ |
acec9514 | 1070 | ctx->cur_header = string_catn(ctx->cur_header, CUS "\r", 1); |
b895f4b2 | 1071 | |
02c4f8fb | 1072 | if (ctx->flags & PDKIM_SEEN_LF) /* Seen last header line */ |
b895f4b2 | 1073 | { |
02c4f8fb JH |
1074 | if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) |
1075 | return rc; | |
b895f4b2 | 1076 | |
863bd541 | 1077 | ctx->flags = (ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR)) | PDKIM_PAST_HDRS; |
b895f4b2 | 1078 | DEBUG(D_acl) debug_printf( |
305f8921 | 1079 | "DKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
b895f4b2 | 1080 | continue; |
3045f050 | 1081 | } |
b895f4b2 | 1082 | else |
863bd541 | 1083 | ctx->flags = (ctx->flags & ~PDKIM_SEEN_CR) | PDKIM_SEEN_LF; |
b895f4b2 JH |
1084 | } |
1085 | else if (ctx->flags & PDKIM_SEEN_LF) | |
1086 | { | |
02c4f8fb JH |
1087 | if (!(c == '\t' || c == ' ')) /* End of header */ |
1088 | if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) | |
1089 | return rc; | |
b895f4b2 | 1090 | ctx->flags &= ~PDKIM_SEEN_LF; |
80a47a2c | 1091 | } |
3045f050 | 1092 | |
acec9514 JH |
1093 | if (!ctx->cur_header || ctx->cur_header->ptr < PDKIM_MAX_HEADER_LEN) |
1094 | ctx->cur_header = string_catn(ctx->cur_header, CUS &data[p], 1); | |
80a47a2c TK |
1095 | } |
1096 | } | |
3045f050 | 1097 | return PDKIM_OK; |
6ab02e3f | 1098 | } |
80a47a2c | 1099 | |
ca9cb170 JH |
1100 | |
1101 | ||
acec9514 JH |
1102 | /* Extend a growing header with a continuation-linebreak */ |
1103 | static gstring * | |
1104 | pdkim_hdr_cont(gstring * str, int * col) | |
ca9cb170 JH |
1105 | { |
1106 | *col = 1; | |
acec9514 | 1107 | return string_catn(str, US"\r\n\t", 3); |
ca9cb170 JH |
1108 | } |
1109 | ||
1110 | ||
1111 | ||
05b7d6de JB |
1112 | /* |
1113 | * RFC 5322 specifies that header line length SHOULD be no more than 78 | |
1114 | * lets make it so! | |
1115 | * pdkim_headcat | |
ca9cb170 JH |
1116 | * |
1117 | * returns uschar * (not nul-terminated) | |
05b7d6de JB |
1118 | * |
1119 | * col: this int holds and receives column number (octets since last '\n') | |
1120 | * str: partial string to append to | |
94431adb | 1121 | * pad: padding, split line or space after before or after eg: ";" |
05b7d6de JB |
1122 | * intro: - must join to payload eg "h=", usually the tag name |
1123 | * payload: eg base64 data - long data can be split arbitrarily. | |
1124 | * | |
1125 | * this code doesn't fold the header in some of the places that RFC4871 | |
1126 | * allows: As per RFC5322(2.2.3) it only folds before or after tag-value | |
1127 | * pairs and inside long values. it also always spaces or breaks after the | |
94431adb | 1128 | * "pad" |
05b7d6de JB |
1129 | * |
1130 | * no guarantees are made for output given out-of range input. like tag | |
f444c2c7 | 1131 | * names longer than 78, or bogus col. Input is assumed to be free of line breaks. |
05b7d6de JB |
1132 | */ |
1133 | ||
acec9514 JH |
1134 | static gstring * |
1135 | pdkim_headcat(int * col, gstring * str, | |
ca9cb170 | 1136 | const uschar * pad, const uschar * intro, const uschar * payload) |
3045f050 JH |
1137 | { |
1138 | size_t l; | |
1139 | ||
1140 | if (pad) | |
05b7d6de | 1141 | { |
ca9cb170 | 1142 | l = Ustrlen(pad); |
3045f050 | 1143 | if (*col + l > 78) |
acec9514 JH |
1144 | str = pdkim_hdr_cont(str, col); |
1145 | str = string_catn(str, pad, l); | |
3045f050 | 1146 | *col += l; |
05b7d6de JB |
1147 | } |
1148 | ||
ca9cb170 | 1149 | l = (pad?1:0) + (intro?Ustrlen(intro):0); |
05b7d6de | 1150 | |
3045f050 | 1151 | if (*col + l > 78) |
05b7d6de | 1152 | { /*can't fit intro - start a new line to make room.*/ |
acec9514 | 1153 | str = pdkim_hdr_cont(str, col); |
ca9cb170 | 1154 | l = intro?Ustrlen(intro):0; |
05b7d6de JB |
1155 | } |
1156 | ||
ca9cb170 | 1157 | l += payload ? Ustrlen(payload):0 ; |
05b7d6de | 1158 | |
3045f050 | 1159 | while (l>77) |
05b7d6de | 1160 | { /* this fragment will not fit on a single line */ |
3045f050 | 1161 | if (pad) |
05b7d6de | 1162 | { |
acec9514 | 1163 | str = string_catn(str, US" ", 1); |
3045f050 JH |
1164 | *col += 1; |
1165 | pad = NULL; /* only want this once */ | |
1166 | l--; | |
05b7d6de | 1167 | } |
3045f050 JH |
1168 | |
1169 | if (intro) | |
05b7d6de | 1170 | { |
ca9cb170 | 1171 | size_t sl = Ustrlen(intro); |
3045f050 | 1172 | |
acec9514 | 1173 | str = string_catn(str, intro, sl); |
3045f050 JH |
1174 | *col += sl; |
1175 | l -= sl; | |
1176 | intro = NULL; /* only want this once */ | |
05b7d6de | 1177 | } |
3045f050 JH |
1178 | |
1179 | if (payload) | |
05b7d6de | 1180 | { |
ca9cb170 | 1181 | size_t sl = Ustrlen(payload); |
3045f050 JH |
1182 | size_t chomp = *col+sl < 77 ? sl : 78-*col; |
1183 | ||
acec9514 | 1184 | str = string_catn(str, payload, chomp); |
3045f050 JH |
1185 | *col += chomp; |
1186 | payload += chomp; | |
1187 | l -= chomp-1; | |
05b7d6de | 1188 | } |
3045f050 JH |
1189 | |
1190 | /* the while precondition tells us it didn't fit. */ | |
acec9514 | 1191 | str = pdkim_hdr_cont(str, col); |
05b7d6de | 1192 | } |
3045f050 JH |
1193 | |
1194 | if (*col + l > 78) | |
05b7d6de | 1195 | { |
acec9514 | 1196 | str = pdkim_hdr_cont(str, col); |
3045f050 | 1197 | pad = NULL; |
05b7d6de JB |
1198 | } |
1199 | ||
3045f050 | 1200 | if (pad) |
05b7d6de | 1201 | { |
acec9514 | 1202 | str = string_catn(str, US" ", 1); |
3045f050 JH |
1203 | *col += 1; |
1204 | pad = NULL; | |
05b7d6de JB |
1205 | } |
1206 | ||
3045f050 | 1207 | if (intro) |
05b7d6de | 1208 | { |
ca9cb170 | 1209 | size_t sl = Ustrlen(intro); |
3045f050 | 1210 | |
acec9514 | 1211 | str = string_catn(str, intro, sl); |
3045f050 JH |
1212 | *col += sl; |
1213 | l -= sl; | |
1214 | intro = NULL; | |
05b7d6de | 1215 | } |
3045f050 JH |
1216 | |
1217 | if (payload) | |
05b7d6de | 1218 | { |
ca9cb170 | 1219 | size_t sl = Ustrlen(payload); |
3045f050 | 1220 | |
acec9514 | 1221 | str = string_catn(str, payload, sl); |
3045f050 | 1222 | *col += sl; |
05b7d6de JB |
1223 | } |
1224 | ||
ca9cb170 | 1225 | return str; |
05b7d6de | 1226 | } |
80a47a2c | 1227 | |
3045f050 | 1228 | |
80a47a2c | 1229 | /* -------------------------------------------------------------------------- */ |
3045f050 | 1230 | |
cf1cce5e JH |
1231 | /* Signing: create signature header |
1232 | */ | |
ca9cb170 | 1233 | static uschar * |
9e70917d | 1234 | pdkim_create_header(pdkim_signature * sig, BOOL final) |
3045f050 | 1235 | { |
ca9cb170 JH |
1236 | uschar * base64_bh; |
1237 | uschar * base64_b; | |
3045f050 | 1238 | int col = 0; |
acec9514 JH |
1239 | gstring * hdr; |
1240 | gstring * canon_all; | |
3045f050 | 1241 | |
acec9514 JH |
1242 | canon_all = string_cat (NULL, pdkim_canons[sig->canon_headers]); |
1243 | canon_all = string_catn(canon_all, US"/", 1); | |
1244 | canon_all = string_cat (canon_all, pdkim_canons[sig->canon_body]); | |
1245 | (void) string_from_gstring(canon_all); | |
3045f050 | 1246 | |
acec9514 JH |
1247 | hdr = string_cat(NULL, US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); |
1248 | col = hdr->ptr; | |
3045f050 JH |
1249 | |
1250 | /* Required and static bits */ | |
acec9514 JH |
1251 | hdr = pdkim_headcat(&col, hdr, US";", US"a=", dkim_sig_to_a_tag(sig)); |
1252 | hdr = pdkim_headcat(&col, hdr, US";", US"q=", pdkim_querymethods[sig->querymethod]); | |
1253 | hdr = pdkim_headcat(&col, hdr, US";", US"c=", canon_all->s); | |
1254 | hdr = pdkim_headcat(&col, hdr, US";", US"d=", sig->domain); | |
1255 | hdr = pdkim_headcat(&col, hdr, US";", US"s=", sig->selector); | |
ca9cb170 JH |
1256 | |
1257 | /* list of header names can be split between items. */ | |
3045f050 | 1258 | { |
e2e3255a | 1259 | uschar * n = string_copy(sig->headernames); |
ca9cb170 JH |
1260 | uschar * i = US"h="; |
1261 | uschar * s = US";"; | |
1262 | ||
1263 | while (*n) | |
05b7d6de | 1264 | { |
ca9cb170 | 1265 | uschar * c = Ustrchr(n, ':'); |
3045f050 | 1266 | |
ca9cb170 | 1267 | if (c) *c ='\0'; |
05b7d6de | 1268 | |
ca9cb170 | 1269 | if (!i) |
acec9514 | 1270 | hdr = pdkim_headcat(&col, hdr, NULL, NULL, US":"); |
05b7d6de | 1271 | |
acec9514 | 1272 | hdr = pdkim_headcat(&col, hdr, s, i, n); |
3045f050 | 1273 | |
ca9cb170 JH |
1274 | if (!c) |
1275 | break; | |
3045f050 | 1276 | |
ca9cb170 JH |
1277 | n = c+1; |
1278 | s = NULL; | |
1279 | i = NULL; | |
80a47a2c | 1280 | } |
ca9cb170 | 1281 | } |
05b7d6de | 1282 | |
cf1cce5e | 1283 | base64_bh = pdkim_encode_base64(&sig->calc_body_hash->bh); |
acec9514 | 1284 | hdr = pdkim_headcat(&col, hdr, US";", US"bh=", base64_bh); |
3045f050 | 1285 | |
ca9cb170 JH |
1286 | /* Optional bits */ |
1287 | if (sig->identity) | |
acec9514 | 1288 | hdr = pdkim_headcat(&col, hdr, US";", US"i=", sig->identity); |
3045f050 | 1289 | |
ca9cb170 JH |
1290 | if (sig->created > 0) |
1291 | { | |
e2e3255a | 1292 | uschar minibuf[20]; |
3045f050 | 1293 | |
e2e3255a | 1294 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created); |
acec9514 | 1295 | hdr = pdkim_headcat(&col, hdr, US";", US"t=", minibuf); |
ca9cb170 | 1296 | } |
3045f050 | 1297 | |
ca9cb170 JH |
1298 | if (sig->expires > 0) |
1299 | { | |
e2e3255a | 1300 | uschar minibuf[20]; |
3045f050 | 1301 | |
e2e3255a | 1302 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires); |
acec9514 | 1303 | hdr = pdkim_headcat(&col, hdr, US";", US"x=", minibuf); |
ca9cb170 | 1304 | } |
3045f050 | 1305 | |
ca9cb170 JH |
1306 | if (sig->bodylength >= 0) |
1307 | { | |
e2e3255a | 1308 | uschar minibuf[20]; |
80a47a2c | 1309 | |
e2e3255a | 1310 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength); |
acec9514 | 1311 | hdr = pdkim_headcat(&col, hdr, US";", US"l=", minibuf); |
3045f050 | 1312 | } |
05b7d6de | 1313 | |
ca9cb170 | 1314 | /* Preliminary or final version? */ |
ea18931d JH |
1315 | if (final) |
1316 | { | |
1317 | base64_b = pdkim_encode_base64(&sig->sighash); | |
acec9514 | 1318 | hdr = pdkim_headcat(&col, hdr, US";", US"b=", base64_b); |
80a47a2c | 1319 | |
ea18931d | 1320 | /* add trailing semicolon: I'm not sure if this is actually needed */ |
acec9514 | 1321 | hdr = pdkim_headcat(&col, hdr, NULL, US";", US""); |
ea18931d JH |
1322 | } |
1323 | else | |
1324 | { | |
1325 | /* To satisfy the rule "all surrounding whitespace [...] deleted" | |
1326 | ( RFC 6376 section 3.7 ) we ensure there is no whitespace here. Otherwise | |
1327 | the headcat routine could insert a linebreak which the relaxer would reduce | |
1328 | to a single space preceding the terminating semicolon, resulting in an | |
1329 | incorrect header-hash. */ | |
acec9514 | 1330 | hdr = pdkim_headcat(&col, hdr, US";", US"b=;", US""); |
ea18931d | 1331 | } |
80a47a2c | 1332 | |
acec9514 | 1333 | return string_from_gstring(hdr); |
80a47a2c TK |
1334 | } |
1335 | ||
1336 | ||
cd1a5fe0 JH |
1337 | /* -------------------------------------------------------------------------- */ |
1338 | ||
321ef002 JH |
1339 | /* According to draft-ietf-dcrup-dkim-crypto-07 "keys are 256 bits" (referring |
1340 | to DNS, hence the pubkey). Check for more than 32 bytes; if so assume the | |
1341 | alternate possible representation (still) being discussed: a | |
1342 | SubjectPublickeyInfo wrapped key - and drop all but the trailing 32-bytes (it | |
1343 | should be a DER, with exactly 12 leading bytes - but we could accept a BER also, | |
1344 | which could be any size). We still rely on the crypto library for checking for | |
1345 | undersize. | |
1346 | ||
1347 | When the RFC is published this should be re-addressed. */ | |
1348 | ||
1349 | static void | |
1350 | check_bare_ed25519_pubkey(pdkim_pubkey * p) | |
1351 | { | |
1352 | int excess = p->key.len - 32; | |
1353 | if (excess > 0) | |
1354 | { | |
305f8921 | 1355 | DEBUG(D_acl) debug_printf("DKIM: unexpected pubkey len %lu\n", p->key.len); |
321ef002 JH |
1356 | p->key.data += excess; p->key.len = 32; |
1357 | } | |
1358 | } | |
1359 | ||
1360 | ||
cd1a5fe0 | 1361 | static pdkim_pubkey * |
b9df1829 JH |
1362 | pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx, |
1363 | const uschar ** errstr) | |
cd1a5fe0 JH |
1364 | { |
1365 | uschar * dns_txt_name, * dns_txt_reply; | |
1366 | pdkim_pubkey * p; | |
cd1a5fe0 JH |
1367 | |
1368 | /* Fetch public key for signing domain, from DNS */ | |
1369 | ||
1370 | dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain); | |
1371 | ||
617d3932 | 1372 | if ( !(dns_txt_reply = ctx->dns_txt_callback(dns_txt_name)) |
cd1a5fe0 JH |
1373 | || dns_txt_reply[0] == '\0' |
1374 | ) | |
1375 | { | |
1376 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1377 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE; | |
1378 | return NULL; | |
1379 | } | |
1380 | ||
1381 | DEBUG(D_acl) | |
1382 | { | |
1383 | debug_printf( | |
305f8921 | 1384 | "DKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n" |
9e70917d JH |
1385 | " %s\n" |
1386 | " Raw record: ", | |
1387 | dns_txt_name); | |
cd1a5fe0 JH |
1388 | pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply)); |
1389 | } | |
1390 | ||
617d3932 | 1391 | if ( !(p = pdkim_parse_pubkey_record(CUS dns_txt_reply)) |
cd1a5fe0 JH |
1392 | || (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0) |
1393 | ) | |
1394 | { | |
1395 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1396 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD; | |
1397 | ||
1398 | DEBUG(D_acl) | |
1399 | { | |
1400 | if (p) | |
1401 | debug_printf(" Invalid public key service type '%s'\n", p->srvtype); | |
1402 | else | |
1403 | debug_printf(" Error while parsing public key record\n"); | |
1404 | debug_printf( | |
305f8921 | 1405 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
cd1a5fe0 JH |
1406 | } |
1407 | return NULL; | |
1408 | } | |
1409 | ||
1410 | DEBUG(D_acl) debug_printf( | |
305f8921 | 1411 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
cd1a5fe0 JH |
1412 | |
1413 | /* Import public key */ | |
286b9d5f | 1414 | |
cb78c1a8 JH |
1415 | /* Normally we use the signature a= tag to tell us the pubkey format. |
1416 | When signing under debug we do a test-import of the pubkey, and at that | |
1417 | time we do not have a signature so we must interpret the pubkey k= tag | |
1418 | instead. Assume writing on the sig is ok in that case. */ | |
1419 | ||
1420 | if (sig->keytype < 0) | |
042e558f JH |
1421 | if ((sig->keytype = pdkim_keyname_to_keytype(p->keytype)) < 0) |
1422 | { | |
1423 | DEBUG(D_acl) debug_printf("verify_init: unhandled keytype %s\n", p->keytype); | |
1424 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1425 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT; | |
1426 | return NULL; | |
1427 | } | |
cb78c1a8 | 1428 | |
321ef002 JH |
1429 | if (sig->keytype == KEYTYPE_ED25519) |
1430 | check_bare_ed25519_pubkey(p); | |
1431 | ||
286b9d5f JH |
1432 | if ((*errstr = exim_dkim_verify_init(&p->key, |
1433 | sig->keytype == KEYTYPE_ED25519 ? KEYFMT_ED25519_BARE : KEYFMT_DER, | |
a841a6ec | 1434 | vctx, &sig->keybits))) |
cd1a5fe0 | 1435 | { |
b9df1829 | 1436 | DEBUG(D_acl) debug_printf("verify_init: %s\n", *errstr); |
cd1a5fe0 JH |
1437 | sig->verify_status = PDKIM_VERIFY_INVALID; |
1438 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT; | |
1439 | return NULL; | |
1440 | } | |
1441 | ||
286b9d5f | 1442 | vctx->keytype = sig->keytype; |
cd1a5fe0 JH |
1443 | return p; |
1444 | } | |
1445 | ||
1446 | ||
042e558f JH |
1447 | /* -------------------------------------------------------------------------- */ |
1448 | /* Sort and filter the sigs developed from the message */ | |
1449 | ||
1450 | static pdkim_signature * | |
1451 | sort_sig_methods(pdkim_signature * siglist) | |
1452 | { | |
1453 | pdkim_signature * yield, ** ss; | |
1454 | const uschar * prefs; | |
1455 | uschar * ele; | |
1456 | int sep; | |
1457 | ||
1458 | if (!siglist) return NULL; | |
1459 | ||
1460 | /* first select in order of hashtypes */ | |
305f8921 | 1461 | DEBUG(D_acl) debug_printf("DKIM: dkim_verify_hashes '%s'\n", dkim_verify_hashes); |
042e558f JH |
1462 | for (prefs = dkim_verify_hashes, sep = 0, yield = NULL, ss = &yield; |
1463 | ele = string_nextinlist(&prefs, &sep, NULL, 0); ) | |
1464 | { | |
1465 | int i = pdkim_hashname_to_hashtype(CUS ele, 0); | |
1466 | for (pdkim_signature * s = siglist, * next, ** prev = &siglist; s; | |
1467 | s = next) | |
1468 | { | |
1469 | next = s->next; | |
1470 | if (s->hashtype == i) | |
1471 | { *prev = next; s->next = NULL; *ss = s; ss = &s->next; } | |
1472 | else | |
1473 | prev = &s->next; | |
1474 | } | |
1475 | } | |
1476 | ||
1477 | /* then in order of keytypes */ | |
1478 | siglist = yield; | |
305f8921 | 1479 | DEBUG(D_acl) debug_printf("DKIM: dkim_verify_keytypes '%s'\n", dkim_verify_keytypes); |
042e558f JH |
1480 | for (prefs = dkim_verify_keytypes, sep = 0, yield = NULL, ss = &yield; |
1481 | ele = string_nextinlist(&prefs, &sep, NULL, 0); ) | |
1482 | { | |
1483 | int i = pdkim_keyname_to_keytype(CUS ele); | |
1484 | for (pdkim_signature * s = siglist, * next, ** prev = &siglist; s; | |
1485 | s = next) | |
1486 | { | |
1487 | next = s->next; | |
1488 | if (s->keytype == i) | |
1489 | { *prev = next; s->next = NULL; *ss = s; ss = &s->next; } | |
1490 | else | |
1491 | prev = &s->next; | |
1492 | } | |
1493 | } | |
1494 | ||
1495 | DEBUG(D_acl) for (pdkim_signature * s = yield; s; s = s->next) | |
1496 | debug_printf(" retain d=%s s=%s a=%s\n", | |
1497 | s->domain, s->selector, dkim_sig_to_a_tag(s)); | |
1498 | return yield; | |
1499 | } | |
1500 | ||
1501 | ||
80a47a2c | 1502 | /* -------------------------------------------------------------------------- */ |
3045f050 JH |
1503 | |
1504 | DLLEXPORT int | |
b9df1829 JH |
1505 | pdkim_feed_finish(pdkim_ctx * ctx, pdkim_signature ** return_signatures, |
1506 | const uschar ** err) | |
3045f050 | 1507 | { |
286b9d5f | 1508 | BOOL verify_pass = FALSE; |
3045f050 JH |
1509 | |
1510 | /* Check if we must still flush a (partial) header. If that is the | |
1511 | case, the message has no body, and we must compute a body hash | |
1512 | out of '<CR><LF>' */ | |
acec9514 | 1513 | if (ctx->cur_header && ctx->cur_header->ptr > 0) |
3045f050 | 1514 | { |
9e70917d JH |
1515 | blob * rnl = NULL; |
1516 | int rc; | |
1517 | ||
1518 | if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) | |
1519 | return rc; | |
1520 | ||
d7978c0f | 1521 | for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next) |
cf1cce5e | 1522 | rnl = pdkim_update_ctx_bodyhash(b, &lineending, rnl); |
9e70917d | 1523 | if (rnl) store_free(rnl); |
80a47a2c | 1524 | } |
3045f050 | 1525 | else |
0d04a285 | 1526 | DEBUG(D_acl) debug_printf( |
305f8921 | 1527 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
80a47a2c | 1528 | |
617d3932 JH |
1529 | /* Build (and/or evaluate) body hash. Do this even if no DKIM sigs, in case we |
1530 | have a hash to do for ARC. */ | |
1531 | ||
1532 | pdkim_finish_bodyhash(ctx); | |
1533 | ||
042e558f JH |
1534 | /* Sort and filter the recived signatures */ |
1535 | ||
1536 | if (!(ctx->flags & PDKIM_MODE_SIGN)) | |
1537 | ctx->sig = sort_sig_methods(ctx->sig); | |
1538 | ||
286b9d5f JH |
1539 | if (!ctx->sig) |
1540 | { | |
305f8921 | 1541 | DEBUG(D_acl) debug_printf("DKIM: no signatures\n"); |
617d3932 | 1542 | *return_signatures = NULL; |
286b9d5f JH |
1543 | return PDKIM_OK; |
1544 | } | |
1545 | ||
d7978c0f | 1546 | for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next) |
3045f050 | 1547 | { |
2592e6c0 | 1548 | hctx hhash_ctx; |
ad6f5499 | 1549 | uschar * sig_hdr = US""; |
2592e6c0 | 1550 | blob hhash; |
acec9514 | 1551 | gstring * hdata = NULL; |
286b9d5f JH |
1552 | es_ctx sctx; |
1553 | ||
617d3932 JH |
1554 | if ( !(ctx->flags & PDKIM_MODE_SIGN) |
1555 | && sig->verify_status == PDKIM_VERIFY_FAIL) | |
1556 | { | |
1557 | DEBUG(D_acl) | |
305f8921 | 1558 | debug_printf("DKIM: [%s] abandoning this signature\n", sig->domain); |
617d3932 JH |
1559 | continue; |
1560 | } | |
1561 | ||
286b9d5f | 1562 | /*XXX The hash of the headers is needed for GCrypt (for which we can do RSA |
042e558f | 1563 | signing only, as it happens) and for either GnuTLS and OpenSSL when we are |
286b9d5f JH |
1564 | signing with EC (specifically, Ed25519). The former is because the GCrypt |
1565 | signing operation is pure (does not do its own hash) so we must hash. The | |
1566 | latter is because we (stupidly, but this is what the IETF draft is saying) | |
1567 | must hash with the declared hash method, then pass the result to the library | |
1568 | hash-and-sign routine (because that's all the libraries are providing. And | |
1569 | we're stuck with whatever that hidden hash method is, too). We may as well | |
1570 | do this hash incrementally. | |
1571 | We don't need the hash we're calculating here for the GnuTLS and OpenSSL | |
1572 | cases of RSA signing, since those library routines can do hash-and-sign. | |
305f8921 | 1573 | |
286b9d5f JH |
1574 | Some time in the future we could easily avoid doing the hash here for those |
1575 | cases (which will be common for a long while. We could also change from | |
1576 | the current copy-all-the-headers-into-one-block, then call the hash-and-sign | |
1577 | implementation - to a proper incremental one. Unfortunately, GnuTLS just | |
1578 | cannot do incremental - either signing or verification. Unsure about GCrypt. | |
1579 | */ | |
1580 | ||
1581 | /*XXX The header hash is also used (so far) by the verify operation */ | |
2592e6c0 | 1582 | |
d73e45df | 1583 | if (!exim_sha_init(&hhash_ctx, pdkim_hashes[sig->hashtype].exim_hashmethod)) |
7b83389d | 1584 | { |
286b9d5f | 1585 | log_write(0, LOG_MAIN|LOG_PANIC, |
305f8921 | 1586 | "DKIM: hash setup error, possibly nonhandled hashtype"); |
7b83389d JH |
1587 | break; |
1588 | } | |
80a47a2c | 1589 | |
9e70917d JH |
1590 | if (ctx->flags & PDKIM_MODE_SIGN) |
1591 | DEBUG(D_acl) debug_printf( | |
305f8921 | 1592 | "DKIM >> Headers to be signed: >>>>>>>>>>>>\n" |
9e70917d JH |
1593 | " %s\n", |
1594 | sig->sign_headers); | |
1595 | ||
0d04a285 | 1596 | DEBUG(D_acl) debug_printf( |
305f8921 | 1597 | "DKIM >> Header data for hash, canonicalized (%-7s), in sequence >>\n", |
4ff848b5 | 1598 | pdkim_canons[sig->canon_headers]); |
3045f050 | 1599 | |
9e70917d | 1600 | |
3045f050 JH |
1601 | /* SIGNING ---------------------------------------------------------------- */ |
1602 | /* When signing, walk through our header list and add them to the hash. As we | |
8ef02a06 JH |
1603 | go, construct a list of the header's names to use for the h= parameter. |
1604 | Then append to that list any remaining header names for which there was no | |
1605 | header to sign. */ | |
3045f050 | 1606 | |
e983e85a | 1607 | if (ctx->flags & PDKIM_MODE_SIGN) |
3045f050 | 1608 | { |
acec9514 | 1609 | gstring * g = NULL; |
8ef02a06 JH |
1610 | const uschar * l; |
1611 | uschar * s; | |
1612 | int sep = 0; | |
3045f050 | 1613 | |
286b9d5f JH |
1614 | /* Import private key, including the keytype which we need for building |
1615 | the signature header */ | |
1616 | ||
617d3932 | 1617 | if ((*err = exim_dkim_signing_init(CUS sig->privkey, &sctx))) |
286b9d5f JH |
1618 | { |
1619 | log_write(0, LOG_MAIN|LOG_PANIC, "signing_init: %s", *err); | |
1620 | return PDKIM_ERR_RSA_PRIVKEY; | |
1621 | } | |
1622 | sig->keytype = sctx.keytype; | |
9e70917d | 1623 | |
d7978c0f JH |
1624 | sig->headernames = NULL; /* Collected signed header names */ |
1625 | for (pdkim_stringlist * p = sig->headers; p; p = p->next) | |
9e70917d JH |
1626 | { |
1627 | uschar * rh = p->value; | |
1628 | ||
1629 | if (header_name_match(rh, sig->sign_headers) == PDKIM_OK) | |
ab9152ff | 1630 | { |
ab9152ff | 1631 | /* Collect header names (Note: colon presence is guaranteed here) */ |
acec9514 | 1632 | g = string_append_listele_n(g, ':', rh, Ustrchr(rh, ':') - rh); |
3045f050 | 1633 | |
9e70917d JH |
1634 | if (sig->canon_headers == PDKIM_CANON_RELAXED) |
1635 | rh = pdkim_relax_header(rh, TRUE); /* cook header for relaxed canon */ | |
3045f050 | 1636 | |
ab9152ff | 1637 | /* Feed header to the hash algorithm */ |
e2e3255a | 1638 | exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); |
f444c2c7 | 1639 | |
ab9152ff | 1640 | /* Remember headers block for signing (when the library cannot do incremental) */ |
286b9d5f | 1641 | /*XXX we could avoid doing this for all but the GnuTLS/RSA case */ |
acec9514 | 1642 | hdata = exim_dkim_data_append(hdata, rh); |
3045f050 | 1643 | |
ab9152ff JH |
1644 | DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); |
1645 | } | |
9e70917d | 1646 | } |
8ef02a06 | 1647 | |
484cc1a9 JH |
1648 | /* Any headers we wanted to sign but were not present must also be listed. |
1649 | Ignore elements that have been ticked-off or are marked as never-oversign. */ | |
1650 | ||
ca9cb170 | 1651 | l = sig->sign_headers; |
8ef02a06 | 1652 | while((s = string_nextinlist(&l, &sep, NULL, 0))) |
484cc1a9 JH |
1653 | { |
1654 | if (*s == '+') /* skip oversigning marker */ | |
1655 | s++; | |
1656 | if (*s != '_' && *s != '=') | |
acec9514 | 1657 | g = string_append_listele(g, ':', s); |
484cc1a9 | 1658 | } |
acec9514 | 1659 | sig->headernames = string_from_gstring(g); |
ca9cb170 JH |
1660 | |
1661 | /* Create signature header with b= omitted */ | |
1662 | sig_hdr = pdkim_create_header(sig, FALSE); | |
80a47a2c | 1663 | } |
37f8b554 | 1664 | |
3045f050 JH |
1665 | /* VERIFICATION ----------------------------------------------------------- */ |
1666 | /* When verifying, walk through the header name list in the h= parameter and | |
1667 | add the headers to the hash in that order. */ | |
1668 | else | |
1669 | { | |
10c50704 | 1670 | uschar * p = sig->headernames; |
2592e6c0 | 1671 | uschar * q; |
3045f050 | 1672 | |
10c50704 | 1673 | if (p) |
3045f050 | 1674 | { |
10c50704 | 1675 | /* clear tags */ |
d7978c0f | 1676 | for (pdkim_stringlist * hdrs = ctx->headers; hdrs; hdrs = hdrs->next) |
10c50704 | 1677 | hdrs->tag = 0; |
3045f050 | 1678 | |
10c50704 JH |
1679 | p = string_copy(p); |
1680 | while(1) | |
1681 | { | |
1682 | if ((q = Ustrchr(p, ':'))) | |
1683 | *q = '\0'; | |
1684 | ||
1685 | /*XXX walk the list of headers in same order as received. */ | |
d7978c0f | 1686 | for (pdkim_stringlist * hdrs = ctx->headers; hdrs; hdrs = hdrs->next) |
10c50704 | 1687 | if ( hdrs->tag == 0 |
4dc2379a | 1688 | && strncasecmp(CCS hdrs->value, CCS p, Ustrlen(p)) == 0 |
10c50704 JH |
1689 | && (hdrs->value)[Ustrlen(p)] == ':' |
1690 | ) | |
1691 | { | |
1692 | /* cook header for relaxed canon, or just copy it for simple */ | |
1693 | ||
1694 | uschar * rh = sig->canon_headers == PDKIM_CANON_RELAXED | |
ea18931d | 1695 | ? pdkim_relax_header(hdrs->value, TRUE) |
10c50704 JH |
1696 | : string_copy(CUS hdrs->value); |
1697 | ||
1698 | /* Feed header to the hash algorithm */ | |
1699 | exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); | |
1700 | ||
1701 | DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); | |
1702 | hdrs->tag = 1; | |
1703 | break; | |
1704 | } | |
3045f050 | 1705 | |
10c50704 JH |
1706 | if (!q) break; |
1707 | p = q+1; | |
1708 | } | |
3045f050 | 1709 | |
10c50704 | 1710 | sig_hdr = string_copy(sig->rawsig_no_b_val); |
80a47a2c | 1711 | } |
80a47a2c TK |
1712 | } |
1713 | ||
0d04a285 | 1714 | DEBUG(D_acl) debug_printf( |
305f8921 | 1715 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
80a47a2c | 1716 | |
9e70917d JH |
1717 | DEBUG(D_acl) |
1718 | { | |
1719 | debug_printf( | |
305f8921 | 1720 | "DKIM >> Signed DKIM-Signature header, pre-canonicalized >>>>>>>>>>>>>\n"); |
9e70917d JH |
1721 | pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr)); |
1722 | debug_printf( | |
305f8921 | 1723 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
9e70917d JH |
1724 | } |
1725 | ||
3045f050 JH |
1726 | /* Relax header if necessary */ |
1727 | if (sig->canon_headers == PDKIM_CANON_RELAXED) | |
ea18931d | 1728 | sig_hdr = pdkim_relax_header(sig_hdr, FALSE); |
80a47a2c | 1729 | |
0d04a285 | 1730 | DEBUG(D_acl) |
3045f050 | 1731 | { |
305f8921 | 1732 | debug_printf("DKIM >> Signed DKIM-Signature header, canonicalized (%-7s) >>>>>>>\n", |
4ff848b5 | 1733 | pdkim_canons[sig->canon_headers]); |
e2e3255a | 1734 | pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr)); |
0d04a285 | 1735 | debug_printf( |
305f8921 | 1736 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
80a47a2c | 1737 | } |
3045f050 JH |
1738 | |
1739 | /* Finalize header hash */ | |
e2e3255a | 1740 | exim_sha_update(&hhash_ctx, CUS sig_hdr, Ustrlen(sig_hdr)); |
2592e6c0 | 1741 | exim_sha_finish(&hhash_ctx, &hhash); |
3045f050 | 1742 | |
f444c2c7 JH |
1743 | DEBUG(D_acl) |
1744 | { | |
305f8921 | 1745 | debug_printf("DKIM [%s] Header %s computed: ", |
9e70917d | 1746 | sig->domain, pdkim_hashes[sig->hashtype].dkim_hashname); |
2592e6c0 | 1747 | pdkim_hexprint(hhash.data, hhash.len); |
80a47a2c TK |
1748 | } |
1749 | ||
9e70917d JH |
1750 | /* Remember headers block for signing (when the signing library cannot do |
1751 | incremental) */ | |
e983e85a | 1752 | if (ctx->flags & PDKIM_MODE_SIGN) |
acec9514 | 1753 | hdata = exim_dkim_data_append(hdata, US sig_hdr); |
f444c2c7 | 1754 | |
3045f050 | 1755 | /* SIGNING ---------------------------------------------------------------- */ |
e983e85a | 1756 | if (ctx->flags & PDKIM_MODE_SIGN) |
3045f050 | 1757 | { |
286b9d5f | 1758 | hashmethod hm = sig->keytype == KEYTYPE_ED25519 |
cb78c1a8 JH |
1759 | #if defined(SIGN_OPENSSL) |
1760 | ? HASH_NULL | |
1761 | #else | |
1762 | ? HASH_SHA2_512 | |
1763 | #endif | |
1764 | : pdkim_hashes[sig->hashtype].exim_hashmethod; | |
f444c2c7 | 1765 | |
286b9d5f JH |
1766 | #ifdef SIGN_HAVE_ED25519 |
1767 | /* For GCrypt, and for EC, we pass the hash-of-headers to the signing | |
1768 | routine. For anything else we just pass the headers. */ | |
f444c2c7 | 1769 | |
286b9d5f | 1770 | if (sig->keytype != KEYTYPE_ED25519) |
f444c2c7 | 1771 | #endif |
286b9d5f JH |
1772 | { |
1773 | hhash.data = hdata->s; | |
1774 | hhash.len = hdata->ptr; | |
1775 | } | |
f444c2c7 | 1776 | |
286b9d5f | 1777 | if ((*err = exim_dkim_sign(&sctx, hm, &hhash, &sig->sighash))) |
f444c2c7 | 1778 | { |
286b9d5f | 1779 | log_write(0, LOG_MAIN|LOG_PANIC, "signing: %s", *err); |
f444c2c7 JH |
1780 | return PDKIM_ERR_RSA_SIGNING; |
1781 | } | |
80a47a2c | 1782 | |
0d04a285 | 1783 | DEBUG(D_acl) |
3045f050 | 1784 | { |
305f8921 | 1785 | debug_printf( "DKIM [%s] b computed: ", sig->domain); |
dcd03763 | 1786 | pdkim_hexprint(sig->sighash.data, sig->sighash.len); |
80a47a2c | 1787 | } |
80a47a2c | 1788 | |
ca9cb170 | 1789 | sig->signature_header = pdkim_create_header(sig, TRUE); |
80a47a2c | 1790 | } |
80a47a2c | 1791 | |
3045f050 JH |
1792 | /* VERIFICATION ----------------------------------------------------------- */ |
1793 | else | |
1794 | { | |
2592e6c0 | 1795 | ev_ctx vctx; |
cb78c1a8 | 1796 | hashmethod hm; |
3045f050 | 1797 | |
07eeb4df | 1798 | /* Make sure we have all required signature tags */ |
1799 | if (!( sig->domain && *sig->domain | |
1800 | && sig->selector && *sig->selector | |
1801 | && sig->headernames && *sig->headernames | |
1802 | && sig->bodyhash.data | |
dcd03763 | 1803 | && sig->sighash.data |
d73e45df JH |
1804 | && sig->keytype >= 0 |
1805 | && sig->hashtype >= 0 | |
07eeb4df | 1806 | && sig->version |
1807 | ) ) | |
1808 | { | |
1809 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1810 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR; | |
1811 | ||
1812 | DEBUG(D_acl) debug_printf( | |
d9604f37 | 1813 | " Error in DKIM-Signature header: tags missing or invalid (%s)\n" |
305f8921 | 1814 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n", |
d9604f37 JH |
1815 | !(sig->domain && *sig->domain) ? "d=" |
1816 | : !(sig->selector && *sig->selector) ? "s=" | |
1817 | : !(sig->headernames && *sig->headernames) ? "h=" | |
1818 | : !sig->bodyhash.data ? "bh=" | |
1819 | : !sig->sighash.data ? "b=" | |
1820 | : sig->keytype < 0 || sig->hashtype < 0 ? "a=" | |
1821 | : "v=" | |
1822 | ); | |
07eeb4df | 1823 | goto NEXT_VERIFY; |
1824 | } | |
305f8921 | 1825 | |
07eeb4df | 1826 | /* Make sure sig uses supported DKIM version (only v1) */ |
1827 | if (sig->version != 1) | |
1828 | { | |
1829 | sig->verify_status = PDKIM_VERIFY_INVALID; | |
1830 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_DKIM_VERSION; | |
1831 | ||
1832 | DEBUG(D_acl) debug_printf( | |
1833 | " Error in DKIM-Signature header: unsupported DKIM version\n" | |
305f8921 | 1834 | "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
07eeb4df | 1835 | goto NEXT_VERIFY; |
1836 | } | |
1837 | ||
9e70917d JH |
1838 | DEBUG(D_acl) |
1839 | { | |
305f8921 | 1840 | debug_printf( "DKIM [%s] b from mail: ", sig->domain); |
9e70917d JH |
1841 | pdkim_hexprint(sig->sighash.data, sig->sighash.len); |
1842 | } | |
1843 | ||
b9df1829 | 1844 | if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx, err))) |
286b9d5f | 1845 | { |
305f8921 | 1846 | log_write(0, LOG_MAIN, "DKIM: %s%s %s%s [failed key import]", |
286b9d5f JH |
1847 | sig->domain ? "d=" : "", sig->domain ? sig->domain : US"", |
1848 | sig->selector ? "s=" : "", sig->selector ? sig->selector : US""); | |
3045f050 | 1849 | goto NEXT_VERIFY; |
286b9d5f | 1850 | } |
80a47a2c | 1851 | |
135e9496 JH |
1852 | /* If the pubkey limits to a list of specific hashes, ignore sigs that |
1853 | do not have the hash part of the sig algorithm matching */ | |
1854 | ||
1855 | if (sig->pubkey->hashes) | |
1856 | { | |
1857 | const uschar * list = sig->pubkey->hashes, * ele; | |
1858 | int sep = ':'; | |
1859 | while ((ele = string_nextinlist(&list, &sep, NULL, 0))) | |
d73e45df | 1860 | if (Ustrcmp(ele, pdkim_hashes[sig->hashtype].dkim_hashname) == 0) break; |
135e9496 JH |
1861 | if (!ele) |
1862 | { | |
d73e45df JH |
1863 | DEBUG(D_acl) debug_printf("pubkey h=%s vs. sig a=%s_%s\n", |
1864 | sig->pubkey->hashes, | |
1865 | pdkim_keytypes[sig->keytype], | |
1866 | pdkim_hashes[sig->hashtype].dkim_hashname); | |
135e9496 JH |
1867 | sig->verify_status = PDKIM_VERIFY_FAIL; |
1868 | sig->verify_ext_status = PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH; | |
1869 | goto NEXT_VERIFY; | |
1870 | } | |
1871 | } | |
1872 | ||
cb78c1a8 JH |
1873 | hm = sig->keytype == KEYTYPE_ED25519 |
1874 | #if defined(SIGN_OPENSSL) | |
1875 | ? HASH_NULL | |
1876 | #else | |
1877 | ? HASH_SHA2_512 | |
1878 | #endif | |
1879 | : pdkim_hashes[sig->hashtype].exim_hashmethod; | |
1880 | ||
3045f050 | 1881 | /* Check the signature */ |
cb78c1a8 JH |
1882 | |
1883 | if ((*err = exim_dkim_verify(&vctx, hm, &hhash, &sig->sighash))) | |
3045f050 | 1884 | { |
b9df1829 | 1885 | DEBUG(D_acl) debug_printf("headers verify: %s\n", *err); |
3045f050 JH |
1886 | sig->verify_status = PDKIM_VERIFY_FAIL; |
1887 | sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE; | |
1888 | goto NEXT_VERIFY; | |
ff7ddfd7 | 1889 | } |
be24b950 JH |
1890 | if (*dkim_verify_min_keysizes) |
1891 | { | |
1892 | unsigned minbits; | |
1893 | uschar * ss = expand_getkeyed(US pdkim_keytypes[sig->keytype], | |
1894 | dkim_verify_min_keysizes); | |
1895 | if (ss && (minbits = atoi(CS ss)) > sig->keybits) | |
1896 | { | |
1897 | DEBUG(D_acl) debug_printf("Key too short: Actual: %s %u Minima '%s'\n", | |
1898 | pdkim_keytypes[sig->keytype], sig->keybits, dkim_verify_min_keysizes); | |
1899 | sig->verify_status = PDKIM_VERIFY_FAIL; | |
1900 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE; | |
1901 | } | |
1902 | } | |
ff7ddfd7 | 1903 | |
2592e6c0 | 1904 | |
4c04137d | 1905 | /* We have a winner! (if bodyhash was correct earlier) */ |
3045f050 | 1906 | if (sig->verify_status == PDKIM_VERIFY_NONE) |
286b9d5f | 1907 | { |
3045f050 | 1908 | sig->verify_status = PDKIM_VERIFY_PASS; |
286b9d5f | 1909 | verify_pass = TRUE; |
042e558f | 1910 | if (dkim_verify_minimal) break; |
286b9d5f | 1911 | } |
3045f050 JH |
1912 | |
1913 | NEXT_VERIFY: | |
1914 | ||
0d04a285 | 1915 | DEBUG(D_acl) |
3045f050 | 1916 | { |
305f8921 | 1917 | debug_printf("DKIM [%s] %s signature status: %s", |
286b9d5f JH |
1918 | sig->domain, dkim_sig_to_a_tag(sig), |
1919 | pdkim_verify_status_str(sig->verify_status)); | |
3045f050 | 1920 | if (sig->verify_ext_status > 0) |
0d04a285 | 1921 | debug_printf(" (%s)\n", |
3045f050 JH |
1922 | pdkim_verify_ext_status_str(sig->verify_ext_status)); |
1923 | else | |
0d04a285 | 1924 | debug_printf("\n"); |
80a47a2c | 1925 | } |
80a47a2c | 1926 | } |
80a47a2c TK |
1927 | } |
1928 | ||
3045f050 JH |
1929 | /* If requested, set return pointer to signature(s) */ |
1930 | if (return_signatures) | |
1931 | *return_signatures = ctx->sig; | |
80a47a2c | 1932 | |
286b9d5f JH |
1933 | return ctx->flags & PDKIM_MODE_SIGN || verify_pass |
1934 | ? PDKIM_OK : PDKIM_FAIL; | |
80a47a2c TK |
1935 | } |
1936 | ||
1937 | ||
1938 | /* -------------------------------------------------------------------------- */ | |
3045f050 JH |
1939 | |
1940 | DLLEXPORT pdkim_ctx * | |
fc2ba7b9 | 1941 | pdkim_init_verify(uschar * (*dns_txt_callback)(const uschar *), BOOL dot_stuffing) |
3045f050 | 1942 | { |
ca9cb170 | 1943 | pdkim_ctx * ctx; |
3045f050 | 1944 | |
f3ebb786 | 1945 | ctx = store_get(sizeof(pdkim_ctx), FALSE); |
abe1010c | 1946 | memset(ctx, 0, sizeof(pdkim_ctx)); |
3045f050 | 1947 | |
e983e85a | 1948 | if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM; |
f3ebb786 JH |
1949 | /* The line-buffer is for message data, hence tainted */ |
1950 | ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, TRUE); | |
3045f050 | 1951 | ctx->dns_txt_callback = dns_txt_callback; |
80a47a2c | 1952 | |
3045f050 | 1953 | return ctx; |
80a47a2c TK |
1954 | } |
1955 | ||
1956 | ||
1957 | /* -------------------------------------------------------------------------- */ | |
80a47a2c | 1958 | |
9e70917d JH |
1959 | DLLEXPORT pdkim_signature * |
1960 | pdkim_init_sign(pdkim_ctx * ctx, | |
1961 | uschar * domain, uschar * selector, uschar * privkey, | |
1962 | uschar * hashname, const uschar ** errstr) | |
3045f050 | 1963 | { |
d73e45df | 1964 | int hashtype; |
cd1a5fe0 | 1965 | pdkim_signature * sig; |
80a47a2c | 1966 | |
d73e45df | 1967 | if (!domain || !selector || !privkey) |
3045f050 | 1968 | return NULL; |
80a47a2c | 1969 | |
9e70917d | 1970 | /* Allocate & init one signature struct */ |
80a47a2c | 1971 | |
f3ebb786 | 1972 | sig = store_get(sizeof(pdkim_signature), FALSE); |
abe1010c | 1973 | memset(sig, 0, sizeof(pdkim_signature)); |
80a47a2c | 1974 | |
3045f050 | 1975 | sig->bodylength = -1; |
80a47a2c | 1976 | |
e2e3255a JH |
1977 | sig->domain = string_copy(US domain); |
1978 | sig->selector = string_copy(US selector); | |
d73e45df | 1979 | sig->privkey = string_copy(US privkey); |
286b9d5f | 1980 | sig->keytype = -1; |
cb224393 | 1981 | |
d73e45df JH |
1982 | for (hashtype = 0; hashtype < nelem(pdkim_hashes); hashtype++) |
1983 | if (Ustrcmp(hashname, pdkim_hashes[hashtype].dkim_hashname) == 0) | |
1984 | { sig->hashtype = hashtype; break; } | |
1985 | if (hashtype >= nelem(pdkim_hashes)) | |
7b83389d | 1986 | { |
286b9d5f | 1987 | log_write(0, LOG_MAIN|LOG_PANIC, |
305f8921 | 1988 | "DKIM: unrecognised hashname '%s'", hashname); |
d73e45df JH |
1989 | return NULL; |
1990 | } | |
1991 | ||
cd1a5fe0 JH |
1992 | DEBUG(D_acl) |
1993 | { | |
1994 | pdkim_signature s = *sig; | |
1995 | ev_ctx vctx; | |
1996 | ||
305f8921 | 1997 | debug_printf("DKIM (checking verify key)>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
b9df1829 | 1998 | if (!pdkim_key_from_dns(ctx, &s, &vctx, errstr)) |
cd1a5fe0 | 1999 | debug_printf("WARNING: bad dkim key in dns\n"); |
305f8921 | 2000 | debug_printf("DKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
cd1a5fe0 | 2001 | } |
9e70917d | 2002 | return sig; |
6ab02e3f | 2003 | } |
80a47a2c | 2004 | |
f444c2c7 | 2005 | |
80a47a2c | 2006 | /* -------------------------------------------------------------------------- */ |
3045f050 | 2007 | |
9e70917d JH |
2008 | DLLEXPORT void |
2009 | pdkim_set_optional(pdkim_signature * sig, | |
2010 | char * sign_headers, | |
2011 | char * identity, | |
80a47a2c TK |
2012 | int canon_headers, |
2013 | int canon_body, | |
2014 | long bodylength, | |
80a47a2c | 2015 | unsigned long created, |
3045f050 JH |
2016 | unsigned long expires) |
2017 | { | |
3045f050 | 2018 | if (identity) |
e2e3255a | 2019 | sig->identity = string_copy(US identity); |
80a47a2c | 2020 | |
ca9cb170 JH |
2021 | sig->sign_headers = string_copy(sign_headers |
2022 | ? US sign_headers : US PDKIM_DEFAULT_SIGN_HEADERS); | |
80a47a2c | 2023 | |
8ef02a06 JH |
2024 | sig->canon_headers = canon_headers; |
2025 | sig->canon_body = canon_body; | |
2026 | sig->bodylength = bodylength; | |
2027 | sig->created = created; | |
2028 | sig->expires = expires; | |
80a47a2c | 2029 | |
9e70917d JH |
2030 | return; |
2031 | } | |
2032 | ||
2033 | ||
2034 | ||
cf1cce5e | 2035 | /* Set up a blob for calculating the bodyhash according to the |
617d3932 | 2036 | given needs. Use an existing one if possible, or create a new one. |
cf1cce5e | 2037 | |
617d3932 | 2038 | Return: hashblob pointer, or NULL on error |
cf1cce5e JH |
2039 | */ |
2040 | pdkim_bodyhash * | |
617d3932 JH |
2041 | pdkim_set_bodyhash(pdkim_ctx * ctx, int hashtype, int canon_method, |
2042 | long bodylength) | |
cf1cce5e JH |
2043 | { |
2044 | pdkim_bodyhash * b; | |
2045 | ||
6f47da8d JH |
2046 | if (hashtype == -1 || canon_method == -1) return NULL; |
2047 | ||
cf1cce5e | 2048 | for (b = ctx->bodyhash; b; b = b->next) |
617d3932 JH |
2049 | if ( hashtype == b->hashtype |
2050 | && canon_method == b->canon_method | |
2051 | && bodylength == b->bodylength) | |
2052 | { | |
305f8921 | 2053 | DEBUG(D_receive) debug_printf("DKIM: using existing bodyhash %d/%d/%ld\n", |
617d3932 JH |
2054 | hashtype, canon_method, bodylength); |
2055 | return b; | |
2056 | } | |
cf1cce5e | 2057 | |
305f8921 | 2058 | DEBUG(D_receive) debug_printf("DKIM: new bodyhash %d/%d/%ld\n", |
617d3932 | 2059 | hashtype, canon_method, bodylength); |
f3ebb786 | 2060 | b = store_get(sizeof(pdkim_bodyhash), FALSE); |
cf1cce5e | 2061 | b->next = ctx->bodyhash; |
617d3932 JH |
2062 | b->hashtype = hashtype; |
2063 | b->canon_method = canon_method; | |
2064 | b->bodylength = bodylength; | |
cf1cce5e | 2065 | if (!exim_sha_init(&b->body_hash_ctx, /*XXX hash method: extend for sha512 */ |
617d3932 | 2066 | pdkim_hashes[hashtype].exim_hashmethod)) |
cf1cce5e JH |
2067 | { |
2068 | DEBUG(D_acl) | |
305f8921 | 2069 | debug_printf("DKIM: hash init error, possibly nonhandled hashtype\n"); |
cf1cce5e JH |
2070 | return NULL; |
2071 | } | |
2072 | b->signed_body_bytes = 0; | |
2073 | b->num_buffered_blanklines = 0; | |
2074 | ctx->bodyhash = b; | |
617d3932 JH |
2075 | return b; |
2076 | } | |
2077 | ||
cf1cce5e | 2078 | |
617d3932 JH |
2079 | /* Set up a blob for calculating the bodyhash according to the |
2080 | needs of this signature. Use an existing one if possible, or | |
2081 | create a new one. | |
2082 | ||
2083 | Return: hashblob pointer, or NULL on error (only used as a boolean). | |
2084 | */ | |
2085 | pdkim_bodyhash * | |
2086 | pdkim_set_sig_bodyhash(pdkim_ctx * ctx, pdkim_signature * sig) | |
2087 | { | |
2088 | pdkim_bodyhash * b = pdkim_set_bodyhash(ctx, | |
2089 | sig->hashtype, sig->canon_body, sig->bodylength); | |
cf1cce5e JH |
2090 | sig->calc_body_hash = b; |
2091 | return b; | |
2092 | } | |
2093 | ||
2094 | ||
2095 | /* -------------------------------------------------------------------------- */ | |
2096 | ||
2097 | ||
9e70917d JH |
2098 | void |
2099 | pdkim_init_context(pdkim_ctx * ctx, BOOL dot_stuffed, | |
fc2ba7b9 | 2100 | uschar * (*dns_txt_callback)(const uschar *)) |
9e70917d JH |
2101 | { |
2102 | memset(ctx, 0, sizeof(pdkim_ctx)); | |
2103 | ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN; | |
f3ebb786 JH |
2104 | /* The line buffer is for message data, hence tainted */ |
2105 | ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, TRUE); | |
9e70917d | 2106 | DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback; |
6ab02e3f | 2107 | } |
3045f050 | 2108 | |
3045f050 | 2109 | |
2592e6c0 JH |
2110 | void |
2111 | pdkim_init(void) | |
2112 | { | |
9b2583c4 | 2113 | exim_dkim_init(); |
2592e6c0 JH |
2114 | } |
2115 | ||
2116 | ||
2117 | ||
f444c2c7 | 2118 | #endif /*DISABLE_DKIM*/ |