| 1 | /* |
| 2 | * PDKIM - a RFC4871 (DKIM) implementation |
| 3 | * |
| 4 | * Copyright (C) 2009 - 2016 Tom Kistner <tom@duncanthrax.net> |
| 5 | * Copyright (C) 2016 Jeremy Harris <jgh@exim.org> |
| 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 | |
| 24 | #include "../exim.h" |
| 25 | |
| 26 | |
| 27 | #ifndef DISABLE_DKIM /* entire file */ |
| 28 | |
| 29 | #ifndef SUPPORT_TLS |
| 30 | # error Need SUPPORT_TLS for DKIM |
| 31 | #endif |
| 32 | |
| 33 | #include "crypt_ver.h" |
| 34 | |
| 35 | #ifdef RSA_OPENSSL |
| 36 | # include <openssl/rsa.h> |
| 37 | # include <openssl/ssl.h> |
| 38 | # include <openssl/err.h> |
| 39 | #elif defined(RSA_GNUTLS) |
| 40 | # include <gnutls/gnutls.h> |
| 41 | # include <gnutls/x509.h> |
| 42 | #endif |
| 43 | |
| 44 | #include "pdkim.h" |
| 45 | #include "rsa.h" |
| 46 | |
| 47 | #define PDKIM_SIGNATURE_VERSION "1" |
| 48 | #define PDKIM_PUB_RECORD_VERSION US "DKIM1" |
| 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 { |
| 65 | uschar * value; |
| 66 | int tag; |
| 67 | void * next; |
| 68 | }; |
| 69 | |
| 70 | /* -------------------------------------------------------------------------- */ |
| 71 | /* A bunch of list constants */ |
| 72 | const uschar * pdkim_querymethods[] = { |
| 73 | US"dns/txt", |
| 74 | NULL |
| 75 | }; |
| 76 | const uschar * pdkim_algos[] = { |
| 77 | US"rsa-sha256", |
| 78 | US"rsa-sha1", |
| 79 | NULL |
| 80 | }; |
| 81 | const uschar * pdkim_canons[] = { |
| 82 | US"simple", |
| 83 | US"relaxed", |
| 84 | NULL |
| 85 | }; |
| 86 | const uschar * pdkim_hashes[] = { |
| 87 | US"sha256", |
| 88 | US"sha1", |
| 89 | NULL |
| 90 | }; |
| 91 | const uschar * pdkim_keytypes[] = { |
| 92 | US"rsa", |
| 93 | NULL |
| 94 | }; |
| 95 | |
| 96 | typedef struct pdkim_combined_canon_entry { |
| 97 | const uschar * str; |
| 98 | int canon_headers; |
| 99 | int canon_body; |
| 100 | } pdkim_combined_canon_entry; |
| 101 | |
| 102 | pdkim_combined_canon_entry pdkim_combined_canons[] = { |
| 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 } |
| 110 | }; |
| 111 | |
| 112 | |
| 113 | /* -------------------------------------------------------------------------- */ |
| 114 | |
| 115 | const char * |
| 116 | pdkim_verify_status_str(int status) |
| 117 | { |
| 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"; |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | const char * |
| 129 | pdkim_verify_ext_status_str(int ext_status) |
| 130 | { |
| 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 | |
| 145 | const char * |
| 146 | pdkim_errstr(int status) |
| 147 | { |
| 148 | switch(status) |
| 149 | { |
| 150 | case PDKIM_OK: return "OK"; |
| 151 | case PDKIM_FAIL: return "FAIL"; |
| 152 | case PDKIM_ERR_RSA_PRIVKEY: return "RSA_PRIVKEY"; |
| 153 | case PDKIM_ERR_RSA_SIGNING: return "RSA SIGNING"; |
| 154 | case PDKIM_ERR_LONG_LINE: return "RSA_LONG_LINE"; |
| 155 | case PDKIM_ERR_BUFFER_TOO_SMALL: return "BUFFER_TOO_SMALL"; |
| 156 | case PDKIM_SIGN_PRIVKEY_WRAP: return "PRIVKEY_WRAP"; |
| 157 | case PDKIM_SIGN_PRIVKEY_B64D: return "PRIVKEY_B64D"; |
| 158 | default: return "(unknown)"; |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | |
| 163 | /* -------------------------------------------------------------------------- */ |
| 164 | /* Print debugging functions */ |
| 165 | static void |
| 166 | pdkim_quoteprint(const uschar *data, int len) |
| 167 | { |
| 168 | int i; |
| 169 | for (i = 0; i < len; i++) |
| 170 | { |
| 171 | const int c = data[i]; |
| 172 | switch (c) |
| 173 | { |
| 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; |
| 180 | default: |
| 181 | if ( (c < 32) || (c > 127) ) |
| 182 | debug_printf("{%02x}", c); |
| 183 | else |
| 184 | debug_printf("%c", c); |
| 185 | break; |
| 186 | } |
| 187 | } |
| 188 | debug_printf("\n"); |
| 189 | } |
| 190 | |
| 191 | static void |
| 192 | pdkim_hexprint(const uschar *data, int len) |
| 193 | { |
| 194 | int i; |
| 195 | for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]); |
| 196 | debug_printf("\n"); |
| 197 | } |
| 198 | |
| 199 | |
| 200 | |
| 201 | static pdkim_stringlist * |
| 202 | pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str) |
| 203 | { |
| 204 | pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist)); |
| 205 | |
| 206 | memset(new_entry, 0, sizeof(pdkim_stringlist)); |
| 207 | new_entry->value = string_copy(str); |
| 208 | if (base) new_entry->next = base; |
| 209 | return new_entry; |
| 210 | } |
| 211 | |
| 212 | |
| 213 | |
| 214 | /* Trim whitespace fore & aft */ |
| 215 | |
| 216 | static void |
| 217 | pdkim_strtrim(uschar * str) |
| 218 | { |
| 219 | uschar * p = str; |
| 220 | uschar * q = str; |
| 221 | while (*p == '\t' || *p == ' ') p++; /* skip whitespace */ |
| 222 | while (*p) {*q = *p; q++; p++;} /* dump the leading whitespace */ |
| 223 | *q = '\0'; |
| 224 | while (q != str && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) ) |
| 225 | { /* dump trailing whitespace */ |
| 226 | *q = '\0'; |
| 227 | q--; |
| 228 | } |
| 229 | } |
| 230 | |
| 231 | |
| 232 | |
| 233 | /* -------------------------------------------------------------------------- */ |
| 234 | |
| 235 | DLLEXPORT void |
| 236 | pdkim_free_ctx(pdkim_ctx *ctx) |
| 237 | { |
| 238 | } |
| 239 | |
| 240 | |
| 241 | /* -------------------------------------------------------------------------- */ |
| 242 | /* Matches the name of the passed raw "header" against |
| 243 | the passed colon-separated "tick", and invalidates |
| 244 | the entry in tick. Returns OK or fail-code */ |
| 245 | /*XXX might be safer done using a pdkim_stringlist for "tick" */ |
| 246 | |
| 247 | static int |
| 248 | header_name_match(const uschar * header, uschar * tick) |
| 249 | { |
| 250 | uschar * hname; |
| 251 | uschar * lcopy; |
| 252 | uschar * p; |
| 253 | uschar * q; |
| 254 | uschar * hcolon = Ustrchr(header, ':'); /* Get header name */ |
| 255 | |
| 256 | if (!hcolon) |
| 257 | return PDKIM_FAIL; /* This isn't a header */ |
| 258 | |
| 259 | /* if we had strncmpic() we wouldn't need this copy */ |
| 260 | hname = string_copyn(header, hcolon-header); |
| 261 | |
| 262 | /* Copy tick-off list locally, so we can punch zeroes into it */ |
| 263 | p = lcopy = string_copy(tick); |
| 264 | |
| 265 | for (q = Ustrchr(p, ':'); q; q = Ustrchr(p, ':')) |
| 266 | { |
| 267 | *q = '\0'; |
| 268 | if (strcmpic(p, hname) == 0) |
| 269 | goto found; |
| 270 | |
| 271 | p = q+1; |
| 272 | } |
| 273 | |
| 274 | if (strcmpic(p, hname) == 0) |
| 275 | goto found; |
| 276 | |
| 277 | return PDKIM_FAIL; |
| 278 | |
| 279 | found: |
| 280 | /* Invalidate header name instance in tick-off list */ |
| 281 | tick[p-lcopy] = '_'; |
| 282 | return PDKIM_OK; |
| 283 | } |
| 284 | |
| 285 | |
| 286 | /* -------------------------------------------------------------------------- */ |
| 287 | /* Performs "relaxed" canonicalization of a header. */ |
| 288 | |
| 289 | static uschar * |
| 290 | pdkim_relax_header(const uschar * header, int crlf) |
| 291 | { |
| 292 | BOOL past_field_name = FALSE; |
| 293 | BOOL seen_wsp = FALSE; |
| 294 | const uschar * p; |
| 295 | uschar * relaxed = store_get(Ustrlen(header)+3); |
| 296 | uschar * q = relaxed; |
| 297 | |
| 298 | for (p = header; *p; p++) |
| 299 | { |
| 300 | uschar c = *p; |
| 301 | /* Ignore CR & LF */ |
| 302 | if (c == '\r' || c == '\n') |
| 303 | continue; |
| 304 | if (c == '\t' || c == ' ') |
| 305 | { |
| 306 | if (seen_wsp) |
| 307 | continue; |
| 308 | c = ' '; /* Turns WSP into SP */ |
| 309 | seen_wsp = TRUE; |
| 310 | } |
| 311 | else |
| 312 | if (!past_field_name && c == ':') |
| 313 | { |
| 314 | if (seen_wsp) q--; /* This removes WSP before the colon */ |
| 315 | seen_wsp = TRUE; /* This removes WSP after the colon */ |
| 316 | past_field_name = TRUE; |
| 317 | } |
| 318 | else |
| 319 | seen_wsp = FALSE; |
| 320 | |
| 321 | /* Lowercase header name */ |
| 322 | if (!past_field_name) c = tolower(c); |
| 323 | *q++ = c; |
| 324 | } |
| 325 | |
| 326 | if (q > relaxed && q[-1] == ' ') q--; /* Squash eventual trailing SP */ |
| 327 | |
| 328 | if (crlf) { *q++ = '\r'; *q++ = '\n'; } |
| 329 | *q = '\0'; |
| 330 | return relaxed; |
| 331 | } |
| 332 | |
| 333 | |
| 334 | /* -------------------------------------------------------------------------- */ |
| 335 | #define PDKIM_QP_ERROR_DECODE -1 |
| 336 | |
| 337 | static uschar * |
| 338 | pdkim_decode_qp_char(uschar *qp_p, int *c) |
| 339 | { |
| 340 | uschar *initial_pos = qp_p; |
| 341 | |
| 342 | /* Advance one char */ |
| 343 | qp_p++; |
| 344 | |
| 345 | /* Check for two hex digits and decode them */ |
| 346 | if (isxdigit(*qp_p) && isxdigit(qp_p[1])) |
| 347 | { |
| 348 | /* Do hex conversion */ |
| 349 | *c = (isdigit(*qp_p) ? *qp_p - '0' : toupper(*qp_p) - 'A' + 10) << 4; |
| 350 | *c |= isdigit(qp_p[1]) ? qp_p[1] - '0' : toupper(qp_p[1]) - 'A' + 10; |
| 351 | return qp_p + 2; |
| 352 | } |
| 353 | |
| 354 | /* Illegal char here */ |
| 355 | *c = PDKIM_QP_ERROR_DECODE; |
| 356 | return initial_pos; |
| 357 | } |
| 358 | |
| 359 | |
| 360 | /* -------------------------------------------------------------------------- */ |
| 361 | |
| 362 | static uschar * |
| 363 | pdkim_decode_qp(uschar * str) |
| 364 | { |
| 365 | int nchar = 0; |
| 366 | uschar * q; |
| 367 | uschar * p = str; |
| 368 | uschar * n = store_get(Ustrlen(str)+1); |
| 369 | |
| 370 | *n = '\0'; |
| 371 | q = n; |
| 372 | while (*p) |
| 373 | { |
| 374 | if (*p == '=') |
| 375 | { |
| 376 | p = pdkim_decode_qp_char(p, &nchar); |
| 377 | if (nchar >= 0) |
| 378 | { |
| 379 | *q++ = nchar; |
| 380 | continue; |
| 381 | } |
| 382 | } |
| 383 | else |
| 384 | *q++ = *p; |
| 385 | p++; |
| 386 | } |
| 387 | *q = '\0'; |
| 388 | return n; |
| 389 | } |
| 390 | |
| 391 | |
| 392 | /* -------------------------------------------------------------------------- */ |
| 393 | |
| 394 | static void |
| 395 | pdkim_decode_base64(uschar *str, blob * b) |
| 396 | { |
| 397 | int dlen; |
| 398 | dlen = b64decode(str, &b->data); |
| 399 | if (dlen < 0) b->data = NULL; |
| 400 | b->len = dlen; |
| 401 | } |
| 402 | |
| 403 | static uschar * |
| 404 | pdkim_encode_base64(blob * b) |
| 405 | { |
| 406 | return b64encode(b->data, b->len); |
| 407 | } |
| 408 | |
| 409 | |
| 410 | /* -------------------------------------------------------------------------- */ |
| 411 | #define PDKIM_HDR_LIMBO 0 |
| 412 | #define PDKIM_HDR_TAG 1 |
| 413 | #define PDKIM_HDR_VALUE 2 |
| 414 | |
| 415 | static pdkim_signature * |
| 416 | pdkim_parse_sig_header(pdkim_ctx *ctx, uschar * raw_hdr) |
| 417 | { |
| 418 | pdkim_signature *sig ; |
| 419 | uschar *p, *q; |
| 420 | uschar * cur_tag = NULL; int ts = 0, tl = 0; |
| 421 | uschar * cur_val = NULL; int vs = 0, vl = 0; |
| 422 | BOOL past_hname = FALSE; |
| 423 | BOOL in_b_val = FALSE; |
| 424 | int where = PDKIM_HDR_LIMBO; |
| 425 | int i; |
| 426 | |
| 427 | sig = store_get(sizeof(pdkim_signature)); |
| 428 | memset(sig, 0, sizeof(pdkim_signature)); |
| 429 | sig->bodylength = -1; |
| 430 | |
| 431 | /* Set so invalid/missing data error display is accurate */ |
| 432 | sig->algo = -1; |
| 433 | sig->version = 0; |
| 434 | |
| 435 | q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1); |
| 436 | |
| 437 | for (p = raw_hdr; ; p++) |
| 438 | { |
| 439 | char c = *p; |
| 440 | |
| 441 | /* Ignore FWS */ |
| 442 | if (c == '\r' || c == '\n') |
| 443 | goto NEXT_CHAR; |
| 444 | |
| 445 | /* Fast-forward through header name */ |
| 446 | if (!past_hname) |
| 447 | { |
| 448 | if (c == ':') past_hname = TRUE; |
| 449 | goto NEXT_CHAR; |
| 450 | } |
| 451 | |
| 452 | if (where == PDKIM_HDR_LIMBO) |
| 453 | { |
| 454 | /* In limbo, just wait for a tag-char to appear */ |
| 455 | if (!(c >= 'a' && c <= 'z')) |
| 456 | goto NEXT_CHAR; |
| 457 | |
| 458 | where = PDKIM_HDR_TAG; |
| 459 | } |
| 460 | |
| 461 | if (where == PDKIM_HDR_TAG) |
| 462 | { |
| 463 | if (c >= 'a' && c <= 'z') |
| 464 | cur_tag = string_catn(cur_tag, &ts, &tl, p, 1); |
| 465 | |
| 466 | if (c == '=') |
| 467 | { |
| 468 | cur_tag[tl] = '\0'; |
| 469 | if (Ustrcmp(cur_tag, "b") == 0) |
| 470 | { |
| 471 | *q++ = '='; |
| 472 | in_b_val = TRUE; |
| 473 | } |
| 474 | where = PDKIM_HDR_VALUE; |
| 475 | goto NEXT_CHAR; |
| 476 | } |
| 477 | } |
| 478 | |
| 479 | if (where == PDKIM_HDR_VALUE) |
| 480 | { |
| 481 | if (c == '\r' || c == '\n' || c == ' ' || c == '\t') |
| 482 | goto NEXT_CHAR; |
| 483 | |
| 484 | if (c == ';' || c == '\0') |
| 485 | { |
| 486 | if (tl && vl) |
| 487 | { |
| 488 | cur_val[vl] = '\0'; |
| 489 | pdkim_strtrim(cur_val); |
| 490 | |
| 491 | DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val); |
| 492 | |
| 493 | switch (*cur_tag) |
| 494 | { |
| 495 | case 'b': |
| 496 | if (cur_tag[1] == 'h') |
| 497 | pdkim_decode_base64(cur_val, &sig->bodyhash); |
| 498 | else |
| 499 | pdkim_decode_base64(cur_val, &sig->sigdata); |
| 500 | break; |
| 501 | case 'v': |
| 502 | /* We only support version 1, and that is currently the |
| 503 | only version there is. */ |
| 504 | sig->version = |
| 505 | Ustrcmp(cur_val, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1; |
| 506 | break; |
| 507 | case 'a': |
| 508 | for (i = 0; pdkim_algos[i]; i++) |
| 509 | if (Ustrcmp(cur_val, pdkim_algos[i]) == 0) |
| 510 | { |
| 511 | sig->algo = i; |
| 512 | break; |
| 513 | } |
| 514 | break; |
| 515 | case 'c': |
| 516 | for (i = 0; pdkim_combined_canons[i].str; i++) |
| 517 | if (Ustrcmp(cur_val, pdkim_combined_canons[i].str) == 0) |
| 518 | { |
| 519 | sig->canon_headers = pdkim_combined_canons[i].canon_headers; |
| 520 | sig->canon_body = pdkim_combined_canons[i].canon_body; |
| 521 | break; |
| 522 | } |
| 523 | break; |
| 524 | case 'q': |
| 525 | for (i = 0; pdkim_querymethods[i]; i++) |
| 526 | if (Ustrcmp(cur_val, pdkim_querymethods[i]) == 0) |
| 527 | { |
| 528 | sig->querymethod = i; |
| 529 | break; |
| 530 | } |
| 531 | break; |
| 532 | case 's': |
| 533 | sig->selector = string_copy(cur_val); break; |
| 534 | case 'd': |
| 535 | sig->domain = string_copy(cur_val); break; |
| 536 | case 'i': |
| 537 | sig->identity = pdkim_decode_qp(cur_val); break; |
| 538 | case 't': |
| 539 | sig->created = strtoul(CS cur_val, NULL, 10); break; |
| 540 | case 'x': |
| 541 | sig->expires = strtoul(CS cur_val, NULL, 10); break; |
| 542 | case 'l': |
| 543 | sig->bodylength = strtol(CS cur_val, NULL, 10); break; |
| 544 | case 'h': |
| 545 | sig->headernames = string_copy(cur_val); break; |
| 546 | case 'z': |
| 547 | sig->copiedheaders = pdkim_decode_qp(cur_val); break; |
| 548 | default: |
| 549 | DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); |
| 550 | break; |
| 551 | } |
| 552 | } |
| 553 | tl = 0; |
| 554 | vl = 0; |
| 555 | in_b_val = FALSE; |
| 556 | where = PDKIM_HDR_LIMBO; |
| 557 | } |
| 558 | else |
| 559 | cur_val = string_catn(cur_val, &vs, &vl, p, 1); |
| 560 | } |
| 561 | |
| 562 | NEXT_CHAR: |
| 563 | if (c == '\0') |
| 564 | break; |
| 565 | |
| 566 | if (!in_b_val) |
| 567 | *q++ = c; |
| 568 | } |
| 569 | |
| 570 | *q = '\0'; |
| 571 | /* Chomp raw header. The final newline must not be added to the signature. */ |
| 572 | while (--q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n')) |
| 573 | *q = '\0'; |
| 574 | |
| 575 | DEBUG(D_acl) |
| 576 | { |
| 577 | debug_printf( |
| 578 | "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
| 579 | pdkim_quoteprint(US sig->rawsig_no_b_val, Ustrlen(sig->rawsig_no_b_val)); |
| 580 | debug_printf( |
| 581 | "PDKIM >> Sig size: %4u bits\n", (unsigned) sig->sigdata.len*8); |
| 582 | debug_printf( |
| 583 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 584 | } |
| 585 | |
| 586 | exim_sha_init(&sig->body_hash, sig->algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256); |
| 587 | return sig; |
| 588 | } |
| 589 | |
| 590 | |
| 591 | /* -------------------------------------------------------------------------- */ |
| 592 | |
| 593 | static pdkim_pubkey * |
| 594 | pdkim_parse_pubkey_record(pdkim_ctx *ctx, const uschar *raw_record) |
| 595 | { |
| 596 | pdkim_pubkey *pub; |
| 597 | const uschar *p; |
| 598 | uschar * cur_tag = NULL; int ts = 0, tl = 0; |
| 599 | uschar * cur_val = NULL; int vs = 0, vl = 0; |
| 600 | int where = PDKIM_HDR_LIMBO; |
| 601 | |
| 602 | pub = store_get(sizeof(pdkim_pubkey)); |
| 603 | memset(pub, 0, sizeof(pdkim_pubkey)); |
| 604 | |
| 605 | for (p = raw_record; ; p++) |
| 606 | { |
| 607 | uschar c = *p; |
| 608 | |
| 609 | /* Ignore FWS */ |
| 610 | if (c != '\r' && c != '\n') switch (where) |
| 611 | { |
| 612 | case PDKIM_HDR_LIMBO: /* In limbo, just wait for a tag-char to appear */ |
| 613 | if (!(c >= 'a' && c <= 'z')) |
| 614 | break; |
| 615 | where = PDKIM_HDR_TAG; |
| 616 | /*FALLTHROUGH*/ |
| 617 | |
| 618 | case PDKIM_HDR_TAG: |
| 619 | if (c >= 'a' && c <= 'z') |
| 620 | cur_tag = string_catn(cur_tag, &ts, &tl, p, 1); |
| 621 | |
| 622 | if (c == '=') |
| 623 | { |
| 624 | cur_tag[tl] = '\0'; |
| 625 | where = PDKIM_HDR_VALUE; |
| 626 | } |
| 627 | break; |
| 628 | |
| 629 | case PDKIM_HDR_VALUE: |
| 630 | if (c == ';' || c == '\0') |
| 631 | { |
| 632 | if (tl && vl) |
| 633 | { |
| 634 | cur_val[vl] = '\0'; |
| 635 | pdkim_strtrim(cur_val); |
| 636 | DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val); |
| 637 | |
| 638 | switch (cur_tag[0]) |
| 639 | { |
| 640 | case 'v': |
| 641 | pub->version = string_copy(cur_val); break; |
| 642 | case 'h': |
| 643 | case 'k': |
| 644 | /* This field appears to never be used. Also, unclear why |
| 645 | a 'k' (key-type_ would go in this field name. There is a field |
| 646 | "keytype", also never used. |
| 647 | pub->hashes = string_copy(cur_val); |
| 648 | */ |
| 649 | break; |
| 650 | case 'g': |
| 651 | pub->granularity = string_copy(cur_val); break; |
| 652 | case 'n': |
| 653 | pub->notes = pdkim_decode_qp(cur_val); break; |
| 654 | case 'p': |
| 655 | pdkim_decode_base64(US cur_val, &pub->key); break; |
| 656 | case 's': |
| 657 | pub->srvtype = string_copy(cur_val); break; |
| 658 | case 't': |
| 659 | if (Ustrchr(cur_val, 'y') != NULL) pub->testing = 1; |
| 660 | if (Ustrchr(cur_val, 's') != NULL) pub->no_subdomaining = 1; |
| 661 | break; |
| 662 | default: |
| 663 | DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); |
| 664 | break; |
| 665 | } |
| 666 | } |
| 667 | tl = 0; |
| 668 | vl = 0; |
| 669 | where = PDKIM_HDR_LIMBO; |
| 670 | } |
| 671 | else |
| 672 | cur_val = string_catn(cur_val, &vs, &vl, p, 1); |
| 673 | break; |
| 674 | } |
| 675 | |
| 676 | if (c == '\0') break; |
| 677 | } |
| 678 | |
| 679 | /* Set fallback defaults */ |
| 680 | if (!pub->version ) pub->version = string_copy(PDKIM_PUB_RECORD_VERSION); |
| 681 | else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0) return NULL; |
| 682 | |
| 683 | if (!pub->granularity) pub->granularity = string_copy(US"*"); |
| 684 | /* |
| 685 | if (!pub->keytype ) pub->keytype = string_copy(US"rsa"); |
| 686 | */ |
| 687 | if (!pub->srvtype ) pub->srvtype = string_copy(US"*"); |
| 688 | |
| 689 | /* p= is required */ |
| 690 | if (pub->key.data) |
| 691 | return pub; |
| 692 | |
| 693 | return NULL; |
| 694 | } |
| 695 | |
| 696 | |
| 697 | /* -------------------------------------------------------------------------- */ |
| 698 | |
| 699 | static int |
| 700 | pdkim_update_bodyhash(pdkim_ctx *ctx, const char *data, int len) |
| 701 | { |
| 702 | pdkim_signature *sig = ctx->sig; |
| 703 | /* Cache relaxed version of data */ |
| 704 | uschar *relaxed_data = NULL; |
| 705 | int relaxed_len = 0; |
| 706 | |
| 707 | /* Traverse all signatures, updating their hashes. */ |
| 708 | while (sig) |
| 709 | { |
| 710 | /* Defaults to simple canon (no further treatment necessary) */ |
| 711 | const uschar *canon_data = CUS data; |
| 712 | int canon_len = len; |
| 713 | |
| 714 | if (sig->canon_body == PDKIM_CANON_RELAXED) |
| 715 | { |
| 716 | /* Relax the line if not done already */ |
| 717 | if (!relaxed_data) |
| 718 | { |
| 719 | BOOL seen_wsp = FALSE; |
| 720 | const char *p; |
| 721 | int q = 0; |
| 722 | |
| 723 | /* We want to be able to free this else we allocate |
| 724 | for the entire message which could be many MB. Since |
| 725 | we don't know what allocations the SHA routines might |
| 726 | do, not safe to use store_get()/store_reset(). */ |
| 727 | |
| 728 | relaxed_data = store_malloc(len+1); |
| 729 | |
| 730 | for (p = data; *p; p++) |
| 731 | { |
| 732 | char c = *p; |
| 733 | if (c == '\r') |
| 734 | { |
| 735 | if (q > 0 && relaxed_data[q-1] == ' ') |
| 736 | q--; |
| 737 | } |
| 738 | else if (c == '\t' || c == ' ') |
| 739 | { |
| 740 | c = ' '; /* Turns WSP into SP */ |
| 741 | if (seen_wsp) |
| 742 | continue; |
| 743 | seen_wsp = TRUE; |
| 744 | } |
| 745 | else |
| 746 | seen_wsp = FALSE; |
| 747 | relaxed_data[q++] = c; |
| 748 | } |
| 749 | relaxed_data[q] = '\0'; |
| 750 | relaxed_len = q; |
| 751 | } |
| 752 | canon_data = relaxed_data; |
| 753 | canon_len = relaxed_len; |
| 754 | } |
| 755 | |
| 756 | /* Make sure we don't exceed the to-be-signed body length */ |
| 757 | if ( sig->bodylength >= 0 |
| 758 | && sig->signed_body_bytes + (unsigned long)canon_len > sig->bodylength |
| 759 | ) |
| 760 | canon_len = sig->bodylength - sig->signed_body_bytes; |
| 761 | |
| 762 | if (canon_len > 0) |
| 763 | { |
| 764 | exim_sha_update(&sig->body_hash, CUS canon_data, canon_len); |
| 765 | sig->signed_body_bytes += canon_len; |
| 766 | DEBUG(D_acl) pdkim_quoteprint(canon_data, canon_len); |
| 767 | } |
| 768 | |
| 769 | sig = sig->next; |
| 770 | } |
| 771 | |
| 772 | if (relaxed_data) store_free(relaxed_data); |
| 773 | return PDKIM_OK; |
| 774 | } |
| 775 | |
| 776 | |
| 777 | /* -------------------------------------------------------------------------- */ |
| 778 | |
| 779 | static void |
| 780 | pdkim_finish_bodyhash(pdkim_ctx *ctx) |
| 781 | { |
| 782 | pdkim_signature *sig; |
| 783 | |
| 784 | /* Traverse all signatures */ |
| 785 | for (sig = ctx->sig; sig; sig = sig->next) |
| 786 | { /* Finish hashes */ |
| 787 | blob bh; |
| 788 | |
| 789 | exim_sha_finish(&sig->body_hash, &bh); |
| 790 | |
| 791 | DEBUG(D_acl) |
| 792 | { |
| 793 | debug_printf("PDKIM [%s] Body bytes hashed: %lu\n" |
| 794 | "PDKIM [%s] Body hash computed: ", |
| 795 | sig->domain, sig->signed_body_bytes, sig->domain); |
| 796 | pdkim_hexprint(CUS bh.data, bh.len); |
| 797 | } |
| 798 | |
| 799 | /* SIGNING -------------------------------------------------------------- */ |
| 800 | if (ctx->flags & PDKIM_MODE_SIGN) |
| 801 | { |
| 802 | sig->bodyhash = bh; |
| 803 | |
| 804 | /* If bodylength limit is set, and we have received less bytes |
| 805 | than the requested amount, effectively remove the limit tag. */ |
| 806 | if (sig->signed_body_bytes < sig->bodylength) |
| 807 | sig->bodylength = -1; |
| 808 | } |
| 809 | |
| 810 | /* VERIFICATION --------------------------------------------------------- */ |
| 811 | else |
| 812 | { |
| 813 | /* Compare bodyhash */ |
| 814 | if (memcmp(bh.data, sig->bodyhash.data, bh.len) == 0) |
| 815 | { |
| 816 | DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain); |
| 817 | } |
| 818 | else |
| 819 | { |
| 820 | DEBUG(D_acl) |
| 821 | { |
| 822 | debug_printf("PDKIM [%s] Body hash signature from headers: ", sig->domain); |
| 823 | pdkim_hexprint(sig->bodyhash.data, |
| 824 | exim_sha_hashlen(&sig->body_hash)); |
| 825 | debug_printf("PDKIM [%s] Body hash did NOT verify\n", sig->domain); |
| 826 | } |
| 827 | sig->verify_status = PDKIM_VERIFY_FAIL; |
| 828 | sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY; |
| 829 | } |
| 830 | } |
| 831 | } |
| 832 | } |
| 833 | |
| 834 | |
| 835 | |
| 836 | static int |
| 837 | pdkim_body_complete(pdkim_ctx * ctx) |
| 838 | { |
| 839 | pdkim_signature * sig = ctx->sig; /*XXX assumes only one sig */ |
| 840 | |
| 841 | /* In simple body mode, if any empty lines were buffered, |
| 842 | replace with one. rfc 4871 3.4.3 */ |
| 843 | /*XXX checking the signed-body-bytes is a gross hack; I think |
| 844 | it indicates that all linebreaks should be buffered, including |
| 845 | the one terminating a text line */ |
| 846 | |
| 847 | if ( sig && sig->canon_body == PDKIM_CANON_SIMPLE |
| 848 | && sig->signed_body_bytes == 0 |
| 849 | && ctx->num_buffered_crlf > 0 |
| 850 | ) |
| 851 | pdkim_update_bodyhash(ctx, "\r\n", 2); |
| 852 | |
| 853 | ctx->flags |= PDKIM_SEEN_EOD; |
| 854 | ctx->linebuf_offset = 0; |
| 855 | return PDKIM_OK; |
| 856 | } |
| 857 | |
| 858 | |
| 859 | |
| 860 | /* -------------------------------------------------------------------------- */ |
| 861 | /* Call from pdkim_feed below for processing complete body lines */ |
| 862 | |
| 863 | static int |
| 864 | pdkim_bodyline_complete(pdkim_ctx *ctx) |
| 865 | { |
| 866 | char *p = ctx->linebuf; |
| 867 | int n = ctx->linebuf_offset; |
| 868 | pdkim_signature *sig = ctx->sig; /*XXX assumes only one sig */ |
| 869 | |
| 870 | /* Ignore extra data if we've seen the end-of-data marker */ |
| 871 | if (ctx->flags & PDKIM_SEEN_EOD) goto BAIL; |
| 872 | |
| 873 | /* We've always got one extra byte to stuff a zero ... */ |
| 874 | ctx->linebuf[ctx->linebuf_offset] = '\0'; |
| 875 | |
| 876 | /* Terminate on EOD marker */ |
| 877 | if (ctx->flags & PDKIM_DOT_TERM) |
| 878 | { |
| 879 | if (memcmp(p, ".\r\n", 3) == 0) |
| 880 | return pdkim_body_complete(ctx); |
| 881 | |
| 882 | /* Unstuff dots */ |
| 883 | if (memcmp(p, "..", 2) == 0) |
| 884 | { |
| 885 | p++; |
| 886 | n--; |
| 887 | } |
| 888 | } |
| 889 | |
| 890 | /* Empty lines need to be buffered until we find a non-empty line */ |
| 891 | if (memcmp(p, "\r\n", 2) == 0) |
| 892 | { |
| 893 | ctx->num_buffered_crlf++; |
| 894 | goto BAIL; |
| 895 | } |
| 896 | |
| 897 | if (sig && sig->canon_body == PDKIM_CANON_RELAXED) |
| 898 | { |
| 899 | /* Lines with just spaces need to be buffered too */ |
| 900 | char *check = p; |
| 901 | while (memcmp(check, "\r\n", 2) != 0) |
| 902 | { |
| 903 | char c = *check; |
| 904 | |
| 905 | if (c != '\t' && c != ' ') |
| 906 | goto PROCESS; |
| 907 | check++; |
| 908 | } |
| 909 | |
| 910 | ctx->num_buffered_crlf++; |
| 911 | goto BAIL; |
| 912 | } |
| 913 | |
| 914 | PROCESS: |
| 915 | /* At this point, we have a non-empty line, so release the buffered ones. */ |
| 916 | while (ctx->num_buffered_crlf) |
| 917 | { |
| 918 | pdkim_update_bodyhash(ctx, "\r\n", 2); |
| 919 | ctx->num_buffered_crlf--; |
| 920 | } |
| 921 | |
| 922 | pdkim_update_bodyhash(ctx, p, n); |
| 923 | |
| 924 | BAIL: |
| 925 | ctx->linebuf_offset = 0; |
| 926 | return PDKIM_OK; |
| 927 | } |
| 928 | |
| 929 | |
| 930 | /* -------------------------------------------------------------------------- */ |
| 931 | /* Callback from pdkim_feed below for processing complete headers */ |
| 932 | #define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:" |
| 933 | |
| 934 | static int |
| 935 | pdkim_header_complete(pdkim_ctx *ctx) |
| 936 | { |
| 937 | /* Special case: The last header can have an extra \r appended */ |
| 938 | if ( (ctx->cur_header_len > 1) && |
| 939 | (ctx->cur_header[(ctx->cur_header_len)-1] == '\r') ) |
| 940 | --ctx->cur_header_len; |
| 941 | ctx->cur_header[ctx->cur_header_len] = '\0'; |
| 942 | |
| 943 | ctx->num_headers++; |
| 944 | if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL; |
| 945 | |
| 946 | /* SIGNING -------------------------------------------------------------- */ |
| 947 | if (ctx->flags & PDKIM_MODE_SIGN) |
| 948 | { |
| 949 | pdkim_signature *sig; |
| 950 | |
| 951 | for (sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */ |
| 952 | |
| 953 | /* Add header to the signed headers list (in reverse order) */ |
| 954 | sig->headers = pdkim_prepend_stringlist(sig->headers, |
| 955 | ctx->cur_header); |
| 956 | } |
| 957 | |
| 958 | /* VERIFICATION ----------------------------------------------------------- */ |
| 959 | /* DKIM-Signature: headers are added to the verification list */ |
| 960 | else |
| 961 | { |
| 962 | DEBUG(D_acl) |
| 963 | { |
| 964 | debug_printf("PDKIM >> raw hdr: "); |
| 965 | pdkim_quoteprint(CUS ctx->cur_header, Ustrlen(ctx->cur_header)); |
| 966 | } |
| 967 | if (strncasecmp(CCS ctx->cur_header, |
| 968 | DKIM_SIGNATURE_HEADERNAME, |
| 969 | Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0) |
| 970 | { |
| 971 | pdkim_signature *new_sig; |
| 972 | |
| 973 | /* Create and chain new signature block */ |
| 974 | DEBUG(D_acl) debug_printf( |
| 975 | "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); |
| 976 | |
| 977 | if ((new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header))) |
| 978 | { |
| 979 | pdkim_signature *last_sig = ctx->sig; |
| 980 | if (!last_sig) |
| 981 | ctx->sig = new_sig; |
| 982 | else |
| 983 | { |
| 984 | while (last_sig->next) last_sig = last_sig->next; |
| 985 | last_sig->next = new_sig; |
| 986 | } |
| 987 | } |
| 988 | else |
| 989 | DEBUG(D_acl) debug_printf( |
| 990 | "Error while parsing signature header\n" |
| 991 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 992 | } |
| 993 | |
| 994 | /* every other header is stored for signature verification */ |
| 995 | else |
| 996 | ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header); |
| 997 | } |
| 998 | |
| 999 | BAIL: |
| 1000 | *ctx->cur_header = '\0'; |
| 1001 | ctx->cur_header_len = 0; /* leave buffer for reuse */ |
| 1002 | return PDKIM_OK; |
| 1003 | } |
| 1004 | |
| 1005 | |
| 1006 | |
| 1007 | /* -------------------------------------------------------------------------- */ |
| 1008 | #define HEADER_BUFFER_FRAG_SIZE 256 |
| 1009 | |
| 1010 | DLLEXPORT int |
| 1011 | pdkim_feed(pdkim_ctx *ctx, char *data, int len) |
| 1012 | { |
| 1013 | int p; |
| 1014 | |
| 1015 | /* Alternate EOD signal, used in non-dotstuffing mode */ |
| 1016 | if (!data) |
| 1017 | pdkim_body_complete(ctx); |
| 1018 | |
| 1019 | else for (p = 0; p<len; p++) |
| 1020 | { |
| 1021 | uschar c = data[p]; |
| 1022 | |
| 1023 | if (ctx->flags & PDKIM_PAST_HDRS) |
| 1024 | { |
| 1025 | if (c == '\n' && !(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ |
| 1026 | { |
| 1027 | ctx->linebuf[ctx->linebuf_offset++] = '\r'; |
| 1028 | if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) |
| 1029 | return PDKIM_ERR_LONG_LINE; |
| 1030 | } |
| 1031 | |
| 1032 | /* Processing body byte */ |
| 1033 | ctx->linebuf[ctx->linebuf_offset++] = c; |
| 1034 | if (c == '\r') |
| 1035 | ctx->flags |= PDKIM_SEEN_CR; |
| 1036 | else if (c == '\n') |
| 1037 | { |
| 1038 | int rc; |
| 1039 | ctx->flags &= ~PDKIM_SEEN_CR; |
| 1040 | if ((rc = pdkim_bodyline_complete(ctx)) != PDKIM_OK) |
| 1041 | return rc; |
| 1042 | } |
| 1043 | |
| 1044 | if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) |
| 1045 | return PDKIM_ERR_LONG_LINE; |
| 1046 | } |
| 1047 | else |
| 1048 | { |
| 1049 | /* Processing header byte */ |
| 1050 | if (c == '\r') |
| 1051 | ctx->flags |= PDKIM_SEEN_CR; |
| 1052 | else if (c == '\n') |
| 1053 | { |
| 1054 | if (!(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ |
| 1055 | ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size, |
| 1056 | &ctx->cur_header_len, CUS "\r", 1); |
| 1057 | |
| 1058 | if (ctx->flags & PDKIM_SEEN_LF) |
| 1059 | { |
| 1060 | int rc = pdkim_header_complete(ctx); /* Seen last header line */ |
| 1061 | if (rc != PDKIM_OK) return rc; |
| 1062 | |
| 1063 | ctx->flags = ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR) | PDKIM_PAST_HDRS; |
| 1064 | DEBUG(D_acl) debug_printf( |
| 1065 | "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>\n"); |
| 1066 | continue; |
| 1067 | } |
| 1068 | else |
| 1069 | ctx->flags = ctx->flags & ~PDKIM_SEEN_CR | PDKIM_SEEN_LF; |
| 1070 | } |
| 1071 | else if (ctx->flags & PDKIM_SEEN_LF) |
| 1072 | { |
| 1073 | if (!(c == '\t' || c == ' ')) |
| 1074 | { |
| 1075 | int rc = pdkim_header_complete(ctx); /* End of header */ |
| 1076 | if (rc != PDKIM_OK) return rc; |
| 1077 | } |
| 1078 | ctx->flags &= ~PDKIM_SEEN_LF; |
| 1079 | } |
| 1080 | |
| 1081 | if (ctx->cur_header_len < PDKIM_MAX_HEADER_LEN) |
| 1082 | ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size, |
| 1083 | &ctx->cur_header_len, CUS &data[p], 1); |
| 1084 | } |
| 1085 | } |
| 1086 | return PDKIM_OK; |
| 1087 | } |
| 1088 | |
| 1089 | |
| 1090 | |
| 1091 | /* Extend a grwong header with a continuation-linebreak */ |
| 1092 | static uschar * |
| 1093 | pdkim_hdr_cont(uschar * str, int * size, int * ptr, int * col) |
| 1094 | { |
| 1095 | *col = 1; |
| 1096 | return string_catn(str, size, ptr, US"\r\n\t", 3); |
| 1097 | } |
| 1098 | |
| 1099 | |
| 1100 | |
| 1101 | /* |
| 1102 | * RFC 5322 specifies that header line length SHOULD be no more than 78 |
| 1103 | * lets make it so! |
| 1104 | * pdkim_headcat |
| 1105 | * |
| 1106 | * returns uschar * (not nul-terminated) |
| 1107 | * |
| 1108 | * col: this int holds and receives column number (octets since last '\n') |
| 1109 | * str: partial string to append to |
| 1110 | * size: current buffer size for str |
| 1111 | * ptr: current tail-pointer for str |
| 1112 | * pad: padding, split line or space after before or after eg: ";" |
| 1113 | * intro: - must join to payload eg "h=", usually the tag name |
| 1114 | * payload: eg base64 data - long data can be split arbitrarily. |
| 1115 | * |
| 1116 | * this code doesn't fold the header in some of the places that RFC4871 |
| 1117 | * allows: As per RFC5322(2.2.3) it only folds before or after tag-value |
| 1118 | * pairs and inside long values. it also always spaces or breaks after the |
| 1119 | * "pad" |
| 1120 | * |
| 1121 | * no guarantees are made for output given out-of range input. like tag |
| 1122 | * names longer than 78, or bogus col. Input is assumed to be free of line breaks. |
| 1123 | */ |
| 1124 | |
| 1125 | static uschar * |
| 1126 | pdkim_headcat(int * col, uschar * str, int * size, int * ptr, |
| 1127 | const uschar * pad, const uschar * intro, const uschar * payload) |
| 1128 | { |
| 1129 | size_t l; |
| 1130 | |
| 1131 | if (pad) |
| 1132 | { |
| 1133 | l = Ustrlen(pad); |
| 1134 | if (*col + l > 78) |
| 1135 | str = pdkim_hdr_cont(str, size, ptr, col); |
| 1136 | str = string_catn(str, size, ptr, pad, l); |
| 1137 | *col += l; |
| 1138 | } |
| 1139 | |
| 1140 | l = (pad?1:0) + (intro?Ustrlen(intro):0); |
| 1141 | |
| 1142 | if (*col + l > 78) |
| 1143 | { /*can't fit intro - start a new line to make room.*/ |
| 1144 | str = pdkim_hdr_cont(str, size, ptr, col); |
| 1145 | l = intro?Ustrlen(intro):0; |
| 1146 | } |
| 1147 | |
| 1148 | l += payload ? Ustrlen(payload):0 ; |
| 1149 | |
| 1150 | while (l>77) |
| 1151 | { /* this fragment will not fit on a single line */ |
| 1152 | if (pad) |
| 1153 | { |
| 1154 | str = string_catn(str, size, ptr, US" ", 1); |
| 1155 | *col += 1; |
| 1156 | pad = NULL; /* only want this once */ |
| 1157 | l--; |
| 1158 | } |
| 1159 | |
| 1160 | if (intro) |
| 1161 | { |
| 1162 | size_t sl = Ustrlen(intro); |
| 1163 | |
| 1164 | str = string_catn(str, size, ptr, intro, sl); |
| 1165 | *col += sl; |
| 1166 | l -= sl; |
| 1167 | intro = NULL; /* only want this once */ |
| 1168 | } |
| 1169 | |
| 1170 | if (payload) |
| 1171 | { |
| 1172 | size_t sl = Ustrlen(payload); |
| 1173 | size_t chomp = *col+sl < 77 ? sl : 78-*col; |
| 1174 | |
| 1175 | str = string_catn(str, size, ptr, payload, chomp); |
| 1176 | *col += chomp; |
| 1177 | payload += chomp; |
| 1178 | l -= chomp-1; |
| 1179 | } |
| 1180 | |
| 1181 | /* the while precondition tells us it didn't fit. */ |
| 1182 | str = pdkim_hdr_cont(str, size, ptr, col); |
| 1183 | } |
| 1184 | |
| 1185 | if (*col + l > 78) |
| 1186 | { |
| 1187 | str = pdkim_hdr_cont(str, size, ptr, col); |
| 1188 | pad = NULL; |
| 1189 | } |
| 1190 | |
| 1191 | if (pad) |
| 1192 | { |
| 1193 | str = string_catn(str, size, ptr, US" ", 1); |
| 1194 | *col += 1; |
| 1195 | pad = NULL; |
| 1196 | } |
| 1197 | |
| 1198 | if (intro) |
| 1199 | { |
| 1200 | size_t sl = Ustrlen(intro); |
| 1201 | |
| 1202 | str = string_catn(str, size, ptr, intro, sl); |
| 1203 | *col += sl; |
| 1204 | l -= sl; |
| 1205 | intro = NULL; |
| 1206 | } |
| 1207 | |
| 1208 | if (payload) |
| 1209 | { |
| 1210 | size_t sl = Ustrlen(payload); |
| 1211 | |
| 1212 | str = string_catn(str, size, ptr, payload, sl); |
| 1213 | *col += sl; |
| 1214 | } |
| 1215 | |
| 1216 | return str; |
| 1217 | } |
| 1218 | |
| 1219 | |
| 1220 | /* -------------------------------------------------------------------------- */ |
| 1221 | |
| 1222 | static uschar * |
| 1223 | pdkim_create_header(pdkim_signature *sig, BOOL final) |
| 1224 | { |
| 1225 | uschar * base64_bh; |
| 1226 | uschar * base64_b; |
| 1227 | int col = 0; |
| 1228 | uschar * hdr; int hdr_size = 0, hdr_len = 0; |
| 1229 | uschar * canon_all; int can_size = 0, can_len = 0; |
| 1230 | |
| 1231 | canon_all = string_cat (NULL, &can_size, &can_len, |
| 1232 | pdkim_canons[sig->canon_headers]); |
| 1233 | canon_all = string_catn(canon_all, &can_size, &can_len, US"/", 1); |
| 1234 | canon_all = string_cat (canon_all, &can_size, &can_len, |
| 1235 | pdkim_canons[sig->canon_body]); |
| 1236 | canon_all[can_len] = '\0'; |
| 1237 | |
| 1238 | hdr = string_cat(NULL, &hdr_size, &hdr_len, |
| 1239 | US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); |
| 1240 | col = hdr_len; |
| 1241 | |
| 1242 | /* Required and static bits */ |
| 1243 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"a=", |
| 1244 | pdkim_algos[sig->algo]); |
| 1245 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"q=", |
| 1246 | pdkim_querymethods[sig->querymethod]); |
| 1247 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"c=", |
| 1248 | canon_all); |
| 1249 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"d=", |
| 1250 | sig->domain); |
| 1251 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"s=", |
| 1252 | sig->selector); |
| 1253 | |
| 1254 | /* list of header names can be split between items. */ |
| 1255 | { |
| 1256 | uschar * n = string_copy(sig->headernames); |
| 1257 | uschar * i = US"h="; |
| 1258 | uschar * s = US";"; |
| 1259 | |
| 1260 | while (*n) |
| 1261 | { |
| 1262 | uschar * c = Ustrchr(n, ':'); |
| 1263 | |
| 1264 | if (c) *c ='\0'; |
| 1265 | |
| 1266 | if (!i) |
| 1267 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, NULL, US":"); |
| 1268 | |
| 1269 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, s, i, n); |
| 1270 | |
| 1271 | if (!c) |
| 1272 | break; |
| 1273 | |
| 1274 | n = c+1; |
| 1275 | s = NULL; |
| 1276 | i = NULL; |
| 1277 | } |
| 1278 | } |
| 1279 | |
| 1280 | base64_bh = pdkim_encode_base64(&sig->bodyhash); |
| 1281 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"bh=", base64_bh); |
| 1282 | |
| 1283 | /* Optional bits */ |
| 1284 | if (sig->identity) |
| 1285 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"i=", sig->identity); |
| 1286 | |
| 1287 | if (sig->created > 0) |
| 1288 | { |
| 1289 | uschar minibuf[20]; |
| 1290 | |
| 1291 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created); |
| 1292 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"t=", minibuf); |
| 1293 | } |
| 1294 | |
| 1295 | if (sig->expires > 0) |
| 1296 | { |
| 1297 | uschar minibuf[20]; |
| 1298 | |
| 1299 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires); |
| 1300 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"x=", minibuf); |
| 1301 | } |
| 1302 | |
| 1303 | if (sig->bodylength >= 0) |
| 1304 | { |
| 1305 | uschar minibuf[20]; |
| 1306 | |
| 1307 | snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength); |
| 1308 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"l=", minibuf); |
| 1309 | } |
| 1310 | |
| 1311 | /* Preliminary or final version? */ |
| 1312 | base64_b = final ? pdkim_encode_base64(&sig->sigdata) : US""; |
| 1313 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"b=", base64_b); |
| 1314 | |
| 1315 | /* add trailing semicolon: I'm not sure if this is actually needed */ |
| 1316 | hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, US";", US""); |
| 1317 | |
| 1318 | hdr[hdr_len] = '\0'; |
| 1319 | return hdr; |
| 1320 | } |
| 1321 | |
| 1322 | |
| 1323 | /* -------------------------------------------------------------------------- */ |
| 1324 | |
| 1325 | static pdkim_pubkey * |
| 1326 | pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx) |
| 1327 | { |
| 1328 | uschar * dns_txt_name, * dns_txt_reply; |
| 1329 | pdkim_pubkey * p; |
| 1330 | const uschar * errstr; |
| 1331 | |
| 1332 | /* Fetch public key for signing domain, from DNS */ |
| 1333 | |
| 1334 | dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain); |
| 1335 | |
| 1336 | dns_txt_reply = store_get(PDKIM_DNS_TXT_MAX_RECLEN); |
| 1337 | memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN); |
| 1338 | |
| 1339 | if ( ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK |
| 1340 | || dns_txt_reply[0] == '\0' |
| 1341 | ) |
| 1342 | { |
| 1343 | sig->verify_status = PDKIM_VERIFY_INVALID; |
| 1344 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE; |
| 1345 | return NULL; |
| 1346 | } |
| 1347 | |
| 1348 | DEBUG(D_acl) |
| 1349 | { |
| 1350 | debug_printf( |
| 1351 | "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n" |
| 1352 | " Raw record: "); |
| 1353 | pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply)); |
| 1354 | } |
| 1355 | |
| 1356 | if ( !(p = pdkim_parse_pubkey_record(ctx, CUS dns_txt_reply)) |
| 1357 | || (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0) |
| 1358 | ) |
| 1359 | { |
| 1360 | sig->verify_status = PDKIM_VERIFY_INVALID; |
| 1361 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD; |
| 1362 | |
| 1363 | DEBUG(D_acl) |
| 1364 | { |
| 1365 | if (p) |
| 1366 | debug_printf(" Invalid public key service type '%s'\n", p->srvtype); |
| 1367 | else |
| 1368 | debug_printf(" Error while parsing public key record\n"); |
| 1369 | debug_printf( |
| 1370 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1371 | } |
| 1372 | return NULL; |
| 1373 | } |
| 1374 | |
| 1375 | DEBUG(D_acl) debug_printf( |
| 1376 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1377 | |
| 1378 | /* Import public key */ |
| 1379 | if ((errstr = exim_rsa_verify_init(&p->key, vctx))) |
| 1380 | { |
| 1381 | DEBUG(D_acl) debug_printf("verify_init: %s\n", errstr); |
| 1382 | sig->verify_status = PDKIM_VERIFY_INVALID; |
| 1383 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT; |
| 1384 | return NULL; |
| 1385 | } |
| 1386 | |
| 1387 | return p; |
| 1388 | } |
| 1389 | |
| 1390 | |
| 1391 | /* -------------------------------------------------------------------------- */ |
| 1392 | |
| 1393 | DLLEXPORT int |
| 1394 | pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures) |
| 1395 | { |
| 1396 | pdkim_signature *sig = ctx->sig; |
| 1397 | |
| 1398 | /* Check if we must still flush a (partial) header. If that is the |
| 1399 | case, the message has no body, and we must compute a body hash |
| 1400 | out of '<CR><LF>' */ |
| 1401 | if (ctx->cur_header && ctx->cur_header_len) |
| 1402 | { |
| 1403 | int rc = pdkim_header_complete(ctx); |
| 1404 | if (rc != PDKIM_OK) return rc; |
| 1405 | pdkim_update_bodyhash(ctx, "\r\n", 2); |
| 1406 | } |
| 1407 | else |
| 1408 | DEBUG(D_acl) debug_printf( |
| 1409 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1410 | |
| 1411 | /* Build (and/or evaluate) body hash */ |
| 1412 | pdkim_finish_bodyhash(ctx); |
| 1413 | |
| 1414 | while (sig) |
| 1415 | { |
| 1416 | BOOL is_sha1 = sig->algo == PDKIM_ALGO_RSA_SHA1; |
| 1417 | hctx hhash_ctx; |
| 1418 | uschar * sig_hdr = US""; |
| 1419 | blob hhash; |
| 1420 | blob hdata; |
| 1421 | int hdata_alloc = 0; |
| 1422 | |
| 1423 | hdata.data = NULL; |
| 1424 | hdata.len = 0; |
| 1425 | |
| 1426 | exim_sha_init(&hhash_ctx, is_sha1 ? HASH_SHA1 : HASH_SHA256); |
| 1427 | |
| 1428 | DEBUG(D_acl) debug_printf( |
| 1429 | "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>>>\n"); |
| 1430 | |
| 1431 | /* SIGNING ---------------------------------------------------------------- */ |
| 1432 | /* When signing, walk through our header list and add them to the hash. As we |
| 1433 | go, construct a list of the header's names to use for the h= parameter. |
| 1434 | Then append to that list any remaining header names for which there was no |
| 1435 | header to sign. */ |
| 1436 | |
| 1437 | if (ctx->flags & PDKIM_MODE_SIGN) |
| 1438 | { |
| 1439 | uschar * headernames = NULL; /* Collected signed header names */ |
| 1440 | int hs = 0, hl = 0; |
| 1441 | pdkim_stringlist *p; |
| 1442 | const uschar * l; |
| 1443 | uschar * s; |
| 1444 | int sep = 0; |
| 1445 | |
| 1446 | for (p = sig->headers; p; p = p->next) |
| 1447 | if (header_name_match(p->value, sig->sign_headers) == PDKIM_OK) |
| 1448 | { |
| 1449 | uschar * rh; |
| 1450 | /* Collect header names (Note: colon presence is guaranteed here) */ |
| 1451 | uschar * q = Ustrchr(p->value, ':'); |
| 1452 | |
| 1453 | headernames = string_catn(headernames, &hs, &hl, |
| 1454 | p->value, (q - US p->value) + (p->next ? 1 : 0)); |
| 1455 | |
| 1456 | rh = sig->canon_headers == PDKIM_CANON_RELAXED |
| 1457 | ? pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */ |
| 1458 | : string_copy(CUS p->value); /* just copy it for simple canon */ |
| 1459 | |
| 1460 | /* Feed header to the hash algorithm */ |
| 1461 | exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); |
| 1462 | |
| 1463 | /* Remember headers block for signing (when the library cannot do incremental) */ |
| 1464 | (void) exim_rsa_data_append(&hdata, &hdata_alloc, rh); |
| 1465 | |
| 1466 | DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); |
| 1467 | } |
| 1468 | |
| 1469 | l = sig->sign_headers; |
| 1470 | while((s = string_nextinlist(&l, &sep, NULL, 0))) |
| 1471 | if (*s != '_') |
| 1472 | { /*SSS string_append_listele() */ |
| 1473 | if (hl > 0 && headernames[hl-1] != ':') |
| 1474 | headernames = string_catn(headernames, &hs, &hl, US":", 1); |
| 1475 | |
| 1476 | headernames = string_cat(headernames, &hs, &hl, s); |
| 1477 | } |
| 1478 | headernames[hl] = '\0'; |
| 1479 | |
| 1480 | /* Copy headernames to signature struct */ |
| 1481 | sig->headernames = headernames; |
| 1482 | |
| 1483 | /* Create signature header with b= omitted */ |
| 1484 | sig_hdr = pdkim_create_header(sig, FALSE); |
| 1485 | } |
| 1486 | |
| 1487 | /* VERIFICATION ----------------------------------------------------------- */ |
| 1488 | /* When verifying, walk through the header name list in the h= parameter and |
| 1489 | add the headers to the hash in that order. */ |
| 1490 | else |
| 1491 | { |
| 1492 | uschar * p = sig->headernames; |
| 1493 | uschar * q; |
| 1494 | pdkim_stringlist * hdrs; |
| 1495 | |
| 1496 | if (p) |
| 1497 | { |
| 1498 | /* clear tags */ |
| 1499 | for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) |
| 1500 | hdrs->tag = 0; |
| 1501 | |
| 1502 | p = string_copy(p); |
| 1503 | while(1) |
| 1504 | { |
| 1505 | if ((q = Ustrchr(p, ':'))) |
| 1506 | *q = '\0'; |
| 1507 | |
| 1508 | /*XXX walk the list of headers in same order as received. */ |
| 1509 | for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) |
| 1510 | if ( hdrs->tag == 0 |
| 1511 | && strncasecmp(CCS hdrs->value, CCS p, Ustrlen(p)) == 0 |
| 1512 | && (hdrs->value)[Ustrlen(p)] == ':' |
| 1513 | ) |
| 1514 | { |
| 1515 | /* cook header for relaxed canon, or just copy it for simple */ |
| 1516 | |
| 1517 | uschar * rh = sig->canon_headers == PDKIM_CANON_RELAXED |
| 1518 | ? pdkim_relax_header(hdrs->value, 1) |
| 1519 | : string_copy(CUS hdrs->value); |
| 1520 | |
| 1521 | /* Feed header to the hash algorithm */ |
| 1522 | exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); |
| 1523 | |
| 1524 | DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); |
| 1525 | hdrs->tag = 1; |
| 1526 | break; |
| 1527 | } |
| 1528 | |
| 1529 | if (!q) break; |
| 1530 | p = q+1; |
| 1531 | } |
| 1532 | |
| 1533 | sig_hdr = string_copy(sig->rawsig_no_b_val); |
| 1534 | } |
| 1535 | } |
| 1536 | |
| 1537 | DEBUG(D_acl) debug_printf( |
| 1538 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1539 | |
| 1540 | /* Relax header if necessary */ |
| 1541 | if (sig->canon_headers == PDKIM_CANON_RELAXED) |
| 1542 | sig_hdr = pdkim_relax_header(sig_hdr, 0); |
| 1543 | |
| 1544 | DEBUG(D_acl) |
| 1545 | { |
| 1546 | debug_printf( |
| 1547 | "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n"); |
| 1548 | pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr)); |
| 1549 | debug_printf( |
| 1550 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1551 | } |
| 1552 | |
| 1553 | /* Finalize header hash */ |
| 1554 | exim_sha_update(&hhash_ctx, CUS sig_hdr, Ustrlen(sig_hdr)); |
| 1555 | exim_sha_finish(&hhash_ctx, &hhash); |
| 1556 | |
| 1557 | DEBUG(D_acl) |
| 1558 | { |
| 1559 | debug_printf("PDKIM [%s] Header hash computed: ", sig->domain); |
| 1560 | pdkim_hexprint(hhash.data, hhash.len); |
| 1561 | } |
| 1562 | |
| 1563 | /* Remember headers block for signing (when the library cannot do incremental) */ |
| 1564 | if (ctx->flags & PDKIM_MODE_SIGN) |
| 1565 | (void) exim_rsa_data_append(&hdata, &hdata_alloc, US sig_hdr); |
| 1566 | |
| 1567 | /* SIGNING ---------------------------------------------------------------- */ |
| 1568 | if (ctx->flags & PDKIM_MODE_SIGN) |
| 1569 | { |
| 1570 | es_ctx sctx; |
| 1571 | const uschar * errstr; |
| 1572 | |
| 1573 | /* Import private key */ |
| 1574 | if ((errstr = exim_rsa_signing_init(US sig->rsa_privkey, &sctx))) |
| 1575 | { |
| 1576 | DEBUG(D_acl) debug_printf("signing_init: %s\n", errstr); |
| 1577 | return PDKIM_ERR_RSA_PRIVKEY; |
| 1578 | } |
| 1579 | |
| 1580 | /* Do signing. With OpenSSL we are signing the hash of headers just |
| 1581 | calculated, with GnuTLS we have to sign an entire block of headers |
| 1582 | (due to available interfaces) and it recalculates the hash internally. */ |
| 1583 | |
| 1584 | #if defined(RSA_OPENSSL) || defined(RSA_GCRYPT) |
| 1585 | hdata = hhash; |
| 1586 | #endif |
| 1587 | |
| 1588 | if ((errstr = exim_rsa_sign(&sctx, is_sha1, &hdata, &sig->sigdata))) |
| 1589 | { |
| 1590 | DEBUG(D_acl) debug_printf("signing: %s\n", errstr); |
| 1591 | return PDKIM_ERR_RSA_SIGNING; |
| 1592 | } |
| 1593 | |
| 1594 | DEBUG(D_acl) |
| 1595 | { |
| 1596 | debug_printf( "PDKIM [%s] b computed: ", sig->domain); |
| 1597 | pdkim_hexprint(sig->sigdata.data, sig->sigdata.len); |
| 1598 | } |
| 1599 | |
| 1600 | sig->signature_header = pdkim_create_header(sig, TRUE); |
| 1601 | } |
| 1602 | |
| 1603 | /* VERIFICATION ----------------------------------------------------------- */ |
| 1604 | else |
| 1605 | { |
| 1606 | ev_ctx vctx; |
| 1607 | const uschar * errstr; |
| 1608 | pdkim_pubkey * p; |
| 1609 | |
| 1610 | /* Make sure we have all required signature tags */ |
| 1611 | if (!( sig->domain && *sig->domain |
| 1612 | && sig->selector && *sig->selector |
| 1613 | && sig->headernames && *sig->headernames |
| 1614 | && sig->bodyhash.data |
| 1615 | && sig->sigdata.data |
| 1616 | && sig->algo > -1 |
| 1617 | && sig->version |
| 1618 | ) ) |
| 1619 | { |
| 1620 | sig->verify_status = PDKIM_VERIFY_INVALID; |
| 1621 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR; |
| 1622 | |
| 1623 | DEBUG(D_acl) debug_printf( |
| 1624 | " Error in DKIM-Signature header: tags missing or invalid\n" |
| 1625 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1626 | goto NEXT_VERIFY; |
| 1627 | } |
| 1628 | |
| 1629 | /* Make sure sig uses supported DKIM version (only v1) */ |
| 1630 | if (sig->version != 1) |
| 1631 | { |
| 1632 | sig->verify_status = PDKIM_VERIFY_INVALID; |
| 1633 | sig->verify_ext_status = PDKIM_VERIFY_INVALID_DKIM_VERSION; |
| 1634 | |
| 1635 | DEBUG(D_acl) debug_printf( |
| 1636 | " Error in DKIM-Signature header: unsupported DKIM version\n" |
| 1637 | "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1638 | goto NEXT_VERIFY; |
| 1639 | } |
| 1640 | |
| 1641 | if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx))) |
| 1642 | goto NEXT_VERIFY; |
| 1643 | |
| 1644 | /* Check the signature */ |
| 1645 | if ((errstr = exim_rsa_verify(&vctx, is_sha1, &hhash, &sig->sigdata))) |
| 1646 | { |
| 1647 | DEBUG(D_acl) debug_printf("headers verify: %s\n", errstr); |
| 1648 | sig->verify_status = PDKIM_VERIFY_FAIL; |
| 1649 | sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE; |
| 1650 | goto NEXT_VERIFY; |
| 1651 | } |
| 1652 | |
| 1653 | |
| 1654 | /* We have a winner! (if bodyhash was correct earlier) */ |
| 1655 | if (sig->verify_status == PDKIM_VERIFY_NONE) |
| 1656 | sig->verify_status = PDKIM_VERIFY_PASS; |
| 1657 | |
| 1658 | NEXT_VERIFY: |
| 1659 | |
| 1660 | DEBUG(D_acl) |
| 1661 | { |
| 1662 | debug_printf("PDKIM [%s] signature status: %s", |
| 1663 | sig->domain, pdkim_verify_status_str(sig->verify_status)); |
| 1664 | if (sig->verify_ext_status > 0) |
| 1665 | debug_printf(" (%s)\n", |
| 1666 | pdkim_verify_ext_status_str(sig->verify_ext_status)); |
| 1667 | else |
| 1668 | debug_printf("\n"); |
| 1669 | } |
| 1670 | } |
| 1671 | |
| 1672 | sig = sig->next; |
| 1673 | } |
| 1674 | |
| 1675 | /* If requested, set return pointer to signature(s) */ |
| 1676 | if (return_signatures) |
| 1677 | *return_signatures = ctx->sig; |
| 1678 | |
| 1679 | return PDKIM_OK; |
| 1680 | } |
| 1681 | |
| 1682 | |
| 1683 | /* -------------------------------------------------------------------------- */ |
| 1684 | |
| 1685 | DLLEXPORT pdkim_ctx * |
| 1686 | pdkim_init_verify(int(*dns_txt_callback)(char *, char *), BOOL dot_stuffing) |
| 1687 | { |
| 1688 | pdkim_ctx * ctx; |
| 1689 | |
| 1690 | ctx = store_get(sizeof(pdkim_ctx)); |
| 1691 | memset(ctx, 0, sizeof(pdkim_ctx)); |
| 1692 | |
| 1693 | if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM; |
| 1694 | ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN); |
| 1695 | ctx->dns_txt_callback = dns_txt_callback; |
| 1696 | |
| 1697 | return ctx; |
| 1698 | } |
| 1699 | |
| 1700 | |
| 1701 | /* -------------------------------------------------------------------------- */ |
| 1702 | |
| 1703 | DLLEXPORT pdkim_ctx * |
| 1704 | pdkim_init_sign(char * domain, char * selector, char * rsa_privkey, int algo, |
| 1705 | BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *)) |
| 1706 | { |
| 1707 | pdkim_ctx * ctx; |
| 1708 | pdkim_signature * sig; |
| 1709 | |
| 1710 | if (!domain || !selector || !rsa_privkey) |
| 1711 | return NULL; |
| 1712 | |
| 1713 | ctx = store_get(sizeof(pdkim_ctx) + PDKIM_MAX_BODY_LINE_LEN + sizeof(pdkim_signature)); |
| 1714 | memset(ctx, 0, sizeof(pdkim_ctx)); |
| 1715 | |
| 1716 | ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN; |
| 1717 | ctx->linebuf = CS (ctx+1); |
| 1718 | |
| 1719 | DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback; |
| 1720 | |
| 1721 | sig = (pdkim_signature *)(ctx->linebuf + PDKIM_MAX_BODY_LINE_LEN); |
| 1722 | memset(sig, 0, sizeof(pdkim_signature)); |
| 1723 | |
| 1724 | sig->bodylength = -1; |
| 1725 | ctx->sig = sig; |
| 1726 | |
| 1727 | sig->domain = string_copy(US domain); |
| 1728 | sig->selector = string_copy(US selector); |
| 1729 | sig->rsa_privkey = string_copy(US rsa_privkey); |
| 1730 | sig->algo = algo; |
| 1731 | |
| 1732 | exim_sha_init(&sig->body_hash, algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256); |
| 1733 | |
| 1734 | DEBUG(D_acl) |
| 1735 | { |
| 1736 | pdkim_signature s = *sig; |
| 1737 | ev_ctx vctx; |
| 1738 | |
| 1739 | debug_printf("PDKIM (checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1740 | if (!pdkim_key_from_dns(ctx, &s, &vctx)) |
| 1741 | debug_printf("WARNING: bad dkim key in dns\n"); |
| 1742 | debug_printf("PDKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); |
| 1743 | } |
| 1744 | |
| 1745 | return ctx; |
| 1746 | } |
| 1747 | |
| 1748 | |
| 1749 | /* -------------------------------------------------------------------------- */ |
| 1750 | |
| 1751 | DLLEXPORT int |
| 1752 | pdkim_set_optional(pdkim_ctx *ctx, |
| 1753 | char *sign_headers, |
| 1754 | char *identity, |
| 1755 | int canon_headers, |
| 1756 | int canon_body, |
| 1757 | long bodylength, |
| 1758 | unsigned long created, |
| 1759 | unsigned long expires) |
| 1760 | { |
| 1761 | pdkim_signature * sig = ctx->sig; |
| 1762 | |
| 1763 | if (identity) |
| 1764 | sig->identity = string_copy(US identity); |
| 1765 | |
| 1766 | sig->sign_headers = string_copy(sign_headers |
| 1767 | ? US sign_headers : US PDKIM_DEFAULT_SIGN_HEADERS); |
| 1768 | |
| 1769 | sig->canon_headers = canon_headers; |
| 1770 | sig->canon_body = canon_body; |
| 1771 | sig->bodylength = bodylength; |
| 1772 | sig->created = created; |
| 1773 | sig->expires = expires; |
| 1774 | |
| 1775 | return PDKIM_OK; |
| 1776 | } |
| 1777 | |
| 1778 | |
| 1779 | void |
| 1780 | pdkim_init(void) |
| 1781 | { |
| 1782 | exim_rsa_init(); |
| 1783 | } |
| 1784 | |
| 1785 | |
| 1786 | |
| 1787 | #endif /*DISABLE_DKIM*/ |