| 1 | /************************************************* |
| 2 | * Exim - an Internet mail transport agent * |
| 3 | *************************************************/ |
| 4 | |
| 5 | /* Copyright (c) Jeremy Harris 2014 */ |
| 6 | |
| 7 | /* This module provides TLS (aka SSL) support for Exim using the OpenSSL |
| 8 | library. It is #included into the tls.c file when that library is used. |
| 9 | */ |
| 10 | |
| 11 | |
| 12 | /* Heading stuff */ |
| 13 | |
| 14 | #include <openssl/lhash.h> |
| 15 | #include <openssl/ssl.h> |
| 16 | #include <openssl/err.h> |
| 17 | #include <openssl/rand.h> |
| 18 | #include <openssl/x509v3.h> |
| 19 | |
| 20 | |
| 21 | /***************************************************** |
| 22 | * Export/import a certificate, binary/printable |
| 23 | *****************************************************/ |
| 24 | int |
| 25 | tls_export_cert(uschar * buf, size_t buflen, void * cert) |
| 26 | { |
| 27 | BIO * bp = BIO_new(BIO_s_mem()); |
| 28 | int fail; |
| 29 | |
| 30 | if ((fail = PEM_write_bio_X509(bp, (X509 *)cert) ? 0 : 1)) |
| 31 | log_write(0, LOG_MAIN, "TLS error in certificate export: %s", |
| 32 | ERR_error_string(ERR_get_error(), NULL)); |
| 33 | else |
| 34 | { |
| 35 | char * cp = CS buf; |
| 36 | int n; |
| 37 | buflen -= 2; |
| 38 | for(;;) |
| 39 | { |
| 40 | if ((n = BIO_gets(bp, cp, (int)buflen)) <= 0) break; |
| 41 | cp += n+1; |
| 42 | buflen -= n+1; |
| 43 | cp[-2] = '\\'; cp[-1] = 'n'; /* newline->"\n" */ |
| 44 | } /* compat with string_printing() */ |
| 45 | *cp = '\0'; |
| 46 | } |
| 47 | |
| 48 | BIO_free(bp); |
| 49 | return fail; |
| 50 | } |
| 51 | |
| 52 | int |
| 53 | tls_import_cert(const uschar * buf, void ** cert) |
| 54 | { |
| 55 | void * reset_point = store_get(0); |
| 56 | const uschar * cp = string_unprinting(US buf); |
| 57 | BIO * bp; |
| 58 | X509 * x; |
| 59 | int fail = 0; |
| 60 | |
| 61 | bp = BIO_new_mem_buf(US cp, -1); |
| 62 | if (!(x = PEM_read_bio_X509(bp, NULL, 0, NULL))) |
| 63 | { |
| 64 | log_write(0, LOG_MAIN, "TLS error in certificate import: %s", |
| 65 | ERR_error_string(ERR_get_error(), NULL)); |
| 66 | fail = 1; |
| 67 | } |
| 68 | else |
| 69 | *cert = (void *)x; |
| 70 | BIO_free(bp); |
| 71 | store_reset(reset_point); |
| 72 | return fail; |
| 73 | } |
| 74 | |
| 75 | void |
| 76 | tls_free_cert(void * cert) |
| 77 | { |
| 78 | X509_free((X509 *)cert); |
| 79 | } |
| 80 | |
| 81 | |
| 82 | /***************************************************** |
| 83 | * Certificate field extraction routines |
| 84 | *****************************************************/ |
| 85 | |
| 86 | /* First, some internal service functions */ |
| 87 | |
| 88 | static uschar * |
| 89 | badalloc(void) |
| 90 | { |
| 91 | expand_string_message = US"allocation failure"; |
| 92 | return NULL; |
| 93 | } |
| 94 | |
| 95 | static uschar * |
| 96 | bio_string_copy(BIO * bp, int len) |
| 97 | { |
| 98 | uschar * cp = US""; |
| 99 | len = len > 0 ? (int) BIO_get_mem_data(bp, &cp) : 0; |
| 100 | cp = string_copyn(cp, len); |
| 101 | BIO_free(bp); |
| 102 | return cp; |
| 103 | } |
| 104 | |
| 105 | static uschar * |
| 106 | bio_string_time_to_int(BIO * bp, int len) |
| 107 | { |
| 108 | uschar * cp = US""; |
| 109 | struct tm t; |
| 110 | len = len > 0 ? (int) BIO_get_mem_data(bp, &cp) : 0; |
| 111 | /*XXX %Z might be glibc-specific? */ |
| 112 | (void) strptime(CS cp, "%b%t%e%t%T%t%Y%t%Z", &t); |
| 113 | BIO_free(bp); |
| 114 | /*XXX timegm might not be portable? */ |
| 115 | return string_sprintf("%u", (unsigned) timegm(&t)); |
| 116 | } |
| 117 | |
| 118 | static uschar * |
| 119 | asn1_time_copy(const ASN1_TIME * time, uschar * mod) |
| 120 | { |
| 121 | BIO * bp = BIO_new(BIO_s_mem()); |
| 122 | int len; |
| 123 | |
| 124 | if (!bp) return badalloc(); |
| 125 | |
| 126 | len = ASN1_TIME_print(bp, time); |
| 127 | return mod && Ustrcmp(mod, "int") == 0 |
| 128 | ? bio_string_time_to_int(bp, len) |
| 129 | : bio_string_copy(bp, len); |
| 130 | } |
| 131 | |
| 132 | static uschar * |
| 133 | x509_name_copy(X509_NAME * name) |
| 134 | { |
| 135 | BIO * bp = BIO_new(BIO_s_mem()); |
| 136 | int len_good; |
| 137 | |
| 138 | if (!bp) return badalloc(); |
| 139 | |
| 140 | len_good = |
| 141 | X509_NAME_print_ex(bp, name, 0, XN_FLAG_RFC2253) >= 0 |
| 142 | ? 1 : 0; |
| 143 | return bio_string_copy(bp, len_good); |
| 144 | } |
| 145 | |
| 146 | /**/ |
| 147 | /* Now the extractors, called from expand.c |
| 148 | Arguments: |
| 149 | cert The certificate |
| 150 | mod Optional modifiers for the operator |
| 151 | |
| 152 | Return: |
| 153 | Allocated string with extracted value |
| 154 | */ |
| 155 | |
| 156 | uschar * |
| 157 | tls_cert_issuer(void * cert, uschar * mod) |
| 158 | { |
| 159 | uschar * cp = x509_name_copy(X509_get_issuer_name((X509 *)cert)); |
| 160 | return mod ? tls_field_from_dn(cp, mod) : cp; |
| 161 | } |
| 162 | |
| 163 | uschar * |
| 164 | tls_cert_not_before(void * cert, uschar * mod) |
| 165 | { |
| 166 | return asn1_time_copy(X509_get_notBefore((X509 *)cert), mod); |
| 167 | } |
| 168 | |
| 169 | uschar * |
| 170 | tls_cert_not_after(void * cert, uschar * mod) |
| 171 | { |
| 172 | return asn1_time_copy(X509_get_notAfter((X509 *)cert), mod); |
| 173 | } |
| 174 | |
| 175 | uschar * |
| 176 | tls_cert_serial_number(void * cert, uschar * mod) |
| 177 | { |
| 178 | uschar txt[256]; |
| 179 | BIO * bp = BIO_new(BIO_s_mem()); |
| 180 | int len; |
| 181 | |
| 182 | if (!bp) return badalloc(); |
| 183 | |
| 184 | len = i2a_ASN1_INTEGER(bp, X509_get_serialNumber((X509 *)cert)); |
| 185 | if (len < sizeof(txt)) |
| 186 | BIO_read(bp, txt, len); |
| 187 | else |
| 188 | len = 0; |
| 189 | BIO_free(bp); |
| 190 | return string_copynlc(txt, len); /* lowercase */ |
| 191 | } |
| 192 | |
| 193 | uschar * |
| 194 | tls_cert_signature(void * cert, uschar * mod) |
| 195 | { |
| 196 | uschar * cp = NULL; |
| 197 | BIO * bp = BIO_new(BIO_s_mem()); |
| 198 | |
| 199 | if (!bp) return badalloc(); |
| 200 | |
| 201 | if (X509_print_ex(bp, (X509 *)cert, 0, |
| 202 | X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL | |
| 203 | X509_FLAG_NO_SIGNAME | X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY | |
| 204 | X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS | |
| 205 | /* X509_FLAG_NO_SIGDUMP is the missing one */ |
| 206 | X509_FLAG_NO_AUX) == 1) |
| 207 | { |
| 208 | long len = BIO_get_mem_data(bp, &cp); |
| 209 | |
| 210 | /* Strip leading "Signature Algorithm" line */ |
| 211 | while (*cp && *cp != '\n') { cp++; len--; } |
| 212 | |
| 213 | cp = string_copyn(cp+1, len-1); |
| 214 | } |
| 215 | BIO_free(bp); |
| 216 | return cp; |
| 217 | } |
| 218 | |
| 219 | uschar * |
| 220 | tls_cert_signature_algorithm(void * cert, uschar * mod) |
| 221 | { |
| 222 | uschar * cp = NULL; |
| 223 | BIO * bp = BIO_new(BIO_s_mem()); |
| 224 | |
| 225 | if (!bp) return badalloc(); |
| 226 | |
| 227 | if (X509_print_ex(bp, (X509 *)cert, 0, |
| 228 | X509_FLAG_NO_HEADER | X509_FLAG_NO_VERSION | X509_FLAG_NO_SERIAL | |
| 229 | /* X509_FLAG_NO_SIGNAME is the missing one */ |
| 230 | X509_FLAG_NO_ISSUER | X509_FLAG_NO_VALIDITY | |
| 231 | X509_FLAG_NO_SUBJECT | X509_FLAG_NO_PUBKEY | X509_FLAG_NO_EXTENSIONS | |
| 232 | X509_FLAG_NO_SIGDUMP | X509_FLAG_NO_AUX) == 1) |
| 233 | { |
| 234 | long len = BIO_get_mem_data(bp, &cp); |
| 235 | |
| 236 | /* Strip leading " Signature Algorithm: " and trailing newline */ |
| 237 | while (*cp && *cp != ':') { cp++; len--; } |
| 238 | do { cp++; len--; } while (*cp && *cp == ' '); |
| 239 | if (cp[len-1] == '\n') len--; |
| 240 | |
| 241 | cp = string_copyn(cp, len); |
| 242 | } |
| 243 | BIO_free(bp); |
| 244 | return cp; |
| 245 | } |
| 246 | |
| 247 | uschar * |
| 248 | tls_cert_subject(void * cert, uschar * mod) |
| 249 | { |
| 250 | uschar * cp = x509_name_copy(X509_get_subject_name((X509 *)cert)); |
| 251 | return mod ? tls_field_from_dn(cp, mod) : cp; |
| 252 | } |
| 253 | |
| 254 | uschar * |
| 255 | tls_cert_version(void * cert, uschar * mod) |
| 256 | { |
| 257 | return string_sprintf("%d", X509_get_version((X509 *)cert)); |
| 258 | } |
| 259 | |
| 260 | uschar * |
| 261 | tls_cert_ext_by_oid(void * cert, uschar * oid, int idx) |
| 262 | { |
| 263 | int nid = OBJ_create(CS oid, "", ""); |
| 264 | int nidx = X509_get_ext_by_NID((X509 *)cert, nid, idx); |
| 265 | X509_EXTENSION * ex = X509_get_ext((X509 *)cert, nidx); |
| 266 | ASN1_OCTET_STRING * adata = X509_EXTENSION_get_data(ex); |
| 267 | BIO * bp = BIO_new(BIO_s_mem()); |
| 268 | long len; |
| 269 | uschar * cp1; |
| 270 | uschar * cp2; |
| 271 | uschar * cp3; |
| 272 | |
| 273 | if (!bp) return badalloc(); |
| 274 | |
| 275 | M_ASN1_OCTET_STRING_print(bp, adata); |
| 276 | /* binary data, DER encoded */ |
| 277 | |
| 278 | /* just dump for now */ |
| 279 | len = BIO_get_mem_data(bp, &cp1); |
| 280 | cp3 = cp2 = store_get(len*3+1); |
| 281 | |
| 282 | while(len) |
| 283 | { |
| 284 | sprintf(CS cp2, "%.2x ", *cp1++); |
| 285 | cp2 += 3; |
| 286 | len--; |
| 287 | } |
| 288 | cp2[-1] = '\0'; |
| 289 | |
| 290 | return cp3; |
| 291 | } |
| 292 | |
| 293 | uschar * |
| 294 | tls_cert_subject_altname(void * cert, uschar * mod) |
| 295 | { |
| 296 | uschar * list = NULL; |
| 297 | STACK_OF(GENERAL_NAME) * san = (STACK_OF(GENERAL_NAME) *) |
| 298 | X509_get_ext_d2i((X509 *)cert, NID_subject_alt_name, NULL, NULL); |
| 299 | uschar sep = '\n'; |
| 300 | uschar * tag = US""; |
| 301 | uschar * ele; |
| 302 | int match = -1; |
| 303 | int len; |
| 304 | |
| 305 | if (!san) return NULL; |
| 306 | |
| 307 | while (mod) |
| 308 | { |
| 309 | if (*mod == '>' && *++mod) sep = *mod++; |
| 310 | else if (Ustrcmp(mod, "dns")==0) { match = GEN_DNS; mod += 3; } |
| 311 | else if (Ustrcmp(mod, "uri")==0) { match = GEN_URI; mod += 3; } |
| 312 | else if (Ustrcmp(mod, "mail")==0) { match = GEN_EMAIL; mod += 4; } |
| 313 | else continue; |
| 314 | |
| 315 | if (*mod++ != ',') |
| 316 | break; |
| 317 | } |
| 318 | |
| 319 | while (sk_GENERAL_NAME_num(san) > 0) |
| 320 | { |
| 321 | GENERAL_NAME * namePart = sk_GENERAL_NAME_pop(san); |
| 322 | if (match != -1 && match != namePart->type) |
| 323 | continue; |
| 324 | switch (namePart->type) |
| 325 | { |
| 326 | case GEN_DNS: |
| 327 | tag = US"DNS"; |
| 328 | ele = ASN1_STRING_data(namePart->d.dNSName); |
| 329 | len = ASN1_STRING_length(namePart->d.dNSName); |
| 330 | break; |
| 331 | case GEN_URI: |
| 332 | tag = US"URI"; |
| 333 | ele = ASN1_STRING_data(namePart->d.uniformResourceIdentifier); |
| 334 | len = ASN1_STRING_length(namePart->d.uniformResourceIdentifier); |
| 335 | break; |
| 336 | case GEN_EMAIL: |
| 337 | tag = US"MAIL"; |
| 338 | ele = ASN1_STRING_data(namePart->d.rfc822Name); |
| 339 | len = ASN1_STRING_length(namePart->d.rfc822Name); |
| 340 | break; |
| 341 | default: |
| 342 | continue; /* ignore unrecognised types */ |
| 343 | } |
| 344 | if (ele[len]) /* not nul-terminated */ |
| 345 | ele = string_copyn(ele, len); |
| 346 | |
| 347 | if (Ustrlen(ele) == len) /* ignore any with embedded nul */ |
| 348 | list = string_append_listele(list, sep, |
| 349 | match == -1 ? string_sprintf("%s=%s", tag, ele) : ele); |
| 350 | } |
| 351 | |
| 352 | sk_GENERAL_NAME_free(san); |
| 353 | return list; |
| 354 | } |
| 355 | |
| 356 | uschar * |
| 357 | tls_cert_ocsp_uri(void * cert, uschar * mod) |
| 358 | { |
| 359 | STACK_OF(ACCESS_DESCRIPTION) * ads = (STACK_OF(ACCESS_DESCRIPTION) *) |
| 360 | X509_get_ext_d2i((X509 *)cert, NID_info_access, NULL, NULL); |
| 361 | int adsnum = sk_ACCESS_DESCRIPTION_num(ads); |
| 362 | int i; |
| 363 | uschar sep = '\n'; |
| 364 | uschar * list = NULL; |
| 365 | |
| 366 | if (mod) |
| 367 | if (*mod == '>' && *++mod) sep = *mod++; |
| 368 | |
| 369 | for (i = 0; i < adsnum; i++) |
| 370 | { |
| 371 | ACCESS_DESCRIPTION * ad = sk_ACCESS_DESCRIPTION_value(ads, i); |
| 372 | |
| 373 | if (ad && OBJ_obj2nid(ad->method) == NID_ad_OCSP) |
| 374 | list = string_append_listele(list, sep, |
| 375 | ASN1_STRING_data(ad->location->d.ia5)); |
| 376 | } |
| 377 | return list; |
| 378 | } |
| 379 | |
| 380 | uschar * |
| 381 | tls_cert_crl_uri(void * cert, uschar * mod) |
| 382 | { |
| 383 | STACK_OF(DIST_POINT) * dps = (STACK_OF(DIST_POINT) *) |
| 384 | X509_get_ext_d2i((X509 *)cert, NID_crl_distribution_points, |
| 385 | NULL, NULL); |
| 386 | DIST_POINT * dp; |
| 387 | int dpsnum = sk_DIST_POINT_num(dps); |
| 388 | int i; |
| 389 | uschar sep = '\n'; |
| 390 | uschar * list = NULL; |
| 391 | |
| 392 | if (mod) |
| 393 | if (*mod == '>' && *++mod) sep = *mod++; |
| 394 | |
| 395 | if (dps) for (i = 0; i < dpsnum; i++) |
| 396 | if ((dp = sk_DIST_POINT_value(dps, i))) |
| 397 | { |
| 398 | STACK_OF(GENERAL_NAME) * names = dp->distpoint->name.fullname; |
| 399 | GENERAL_NAME * np; |
| 400 | int nnum = sk_GENERAL_NAME_num(names); |
| 401 | int j; |
| 402 | |
| 403 | for (j = 0; j < nnum; j++) |
| 404 | if ( (np = sk_GENERAL_NAME_value(names, j)) |
| 405 | && np->type == GEN_URI |
| 406 | ) |
| 407 | list = string_append_listele(list, sep, |
| 408 | ASN1_STRING_data(np->d.uniformResourceIdentifier)); |
| 409 | } |
| 410 | return list; |
| 411 | } |
| 412 | |
| 413 | |
| 414 | |
| 415 | /***************************************************** |
| 416 | * Certificate operator routines |
| 417 | *****************************************************/ |
| 418 | static uschar * |
| 419 | fingerprint(X509 * cert, const EVP_MD * fdig) |
| 420 | { |
| 421 | int j; |
| 422 | unsigned int n; |
| 423 | uschar md[EVP_MAX_MD_SIZE]; |
| 424 | uschar * cp; |
| 425 | |
| 426 | if (!X509_digest(cert,fdig,md,&n)) |
| 427 | { |
| 428 | expand_string_message = US"tls_cert_fprt: out of mem\n"; |
| 429 | return NULL; |
| 430 | } |
| 431 | cp = store_get(n*2+1); |
| 432 | for (j = 0; j < (int)n; j++) sprintf(CS cp+2*j, "%02X", md[j]); |
| 433 | return(cp); |
| 434 | } |
| 435 | |
| 436 | uschar * |
| 437 | tls_cert_fprt_md5(void * cert) |
| 438 | { |
| 439 | return fingerprint((X509 *)cert, EVP_md5()); |
| 440 | } |
| 441 | |
| 442 | uschar * |
| 443 | tls_cert_fprt_sha1(void * cert) |
| 444 | { |
| 445 | return fingerprint((X509 *)cert, EVP_sha1()); |
| 446 | } |
| 447 | |
| 448 | uschar * |
| 449 | tls_cert_fprt_sha256(void * cert) |
| 450 | { |
| 451 | return fingerprint((X509 *)cert, EVP_sha256()); |
| 452 | } |
| 453 | |
| 454 | |
| 455 | /* vi: aw ai sw=2 |
| 456 | */ |
| 457 | /* End of tlscert-openssl.c */ |