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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 /* | |
| 6 * Stuff specific to S/MIME policy and interoperability. | |
| 7 * Depends on PKCS7, but there should be no dependency the other way around. | |
| 8 * | |
| 9 * $Id: secmime.c,v 1.6 2012/04/25 14:50:06 gerv%gerv.net Exp $ | |
| 10 */ | |
| 11 | |
| 12 #include "secmime.h" | |
| 13 #include "secoid.h" | |
| 14 #include "pk11func.h" | |
| 15 #include "ciferfam.h" /* for CIPHER_FAMILY symbols */ | |
| 16 #include "secasn1.h" | |
| 17 #include "secitem.h" | |
| 18 #include "cert.h" | |
| 19 #include "key.h" | |
| 20 #include "secerr.h" | |
| 21 | |
| 22 typedef struct smime_cipher_map_struct { | |
| 23 unsigned long cipher; | |
| 24 SECOidTag algtag; | |
| 25 SECItem *parms; | |
| 26 } smime_cipher_map; | |
| 27 | |
| 28 /* | |
| 29 * These are macros because I think some subsequent parameters, | |
| 30 * like those for RC5, will want to use them, too, separately. | |
| 31 */ | |
| 32 #define SMIME_DER_INTVAL_16 SEC_ASN1_INTEGER, 0x01, 0x10 | |
| 33 #define SMIME_DER_INTVAL_40 SEC_ASN1_INTEGER, 0x01, 0x28 | |
| 34 #define SMIME_DER_INTVAL_64 SEC_ASN1_INTEGER, 0x01, 0x40 | |
| 35 #define SMIME_DER_INTVAL_128 SEC_ASN1_INTEGER, 0x02, 0x00, 0x80 | |
| 36 | |
| 37 #ifdef SMIME_DOES_RC5 /* will be needed; quiet unused warning for now */ | |
| 38 static unsigned char smime_int16[] = { SMIME_DER_INTVAL_16 }; | |
| 39 #endif | |
| 40 static unsigned char smime_int40[] = { SMIME_DER_INTVAL_40 }; | |
| 41 static unsigned char smime_int64[] = { SMIME_DER_INTVAL_64 }; | |
| 42 static unsigned char smime_int128[] = { SMIME_DER_INTVAL_128 }; | |
| 43 | |
| 44 static SECItem smime_rc2p40 = { siBuffer, smime_int40, sizeof(smime_int40) }; | |
| 45 static SECItem smime_rc2p64 = { siBuffer, smime_int64, sizeof(smime_int64) }; | |
| 46 static SECItem smime_rc2p128 = { siBuffer, smime_int128, sizeof(smime_int128) }; | |
| 47 | |
| 48 static smime_cipher_map smime_cipher_maps[] = { | |
| 49 { SMIME_RC2_CBC_40, SEC_OID_RC2_CBC, &smime_rc2p40 }, | |
| 50 { SMIME_RC2_CBC_64, SEC_OID_RC2_CBC, &smime_rc2p64 }, | |
| 51 { SMIME_RC2_CBC_128, SEC_OID_RC2_CBC, &smime_rc2p128 }, | |
| 52 #ifdef SMIME_DOES_RC5 | |
| 53 { SMIME_RC5PAD_64_16_40, SEC_OID_RC5_CBC_PAD, &smime_rc5p40 }, | |
| 54 { SMIME_RC5PAD_64_16_64, SEC_OID_RC5_CBC_PAD, &smime_rc5p64 }, | |
| 55 { SMIME_RC5PAD_64_16_128, SEC_OID_RC5_CBC_PAD, &smime_rc5p128 }, | |
| 56 #endif | |
| 57 { SMIME_DES_CBC_56, SEC_OID_DES_CBC, NULL }, | |
| 58 { SMIME_DES_EDE3_168, SEC_OID_DES_EDE3_CBC, NULL } | |
| 59 }; | |
| 60 | |
| 61 /* | |
| 62 * Note, the following value really just needs to be an upper bound | |
| 63 * on the ciphers. | |
| 64 */ | |
| 65 static const int smime_symmetric_count = sizeof(smime_cipher_maps) | |
| 66 / sizeof(smime_cipher_map); | |
| 67 | |
| 68 static unsigned long *smime_prefs, *smime_newprefs; | |
| 69 static int smime_current_pref_index = 0; | |
| 70 static PRBool smime_prefs_complete = PR_FALSE; | |
| 71 static PRBool smime_prefs_changed = PR_TRUE; | |
| 72 | |
| 73 static unsigned long smime_policy_bits = 0; | |
| 74 | |
| 75 | |
| 76 static int | |
| 77 smime_mapi_by_cipher (unsigned long cipher) | |
| 78 { | |
| 79 int i; | |
| 80 | |
| 81 for (i = 0; i < smime_symmetric_count; i++) { | |
| 82 if (smime_cipher_maps[i].cipher == cipher) | |
| 83 break; | |
| 84 } | |
| 85 | |
| 86 if (i == smime_symmetric_count) | |
| 87 return -1; | |
| 88 | |
| 89 return i; | |
| 90 } | |
| 91 | |
| 92 | |
| 93 /* | |
| 94 * this function locally records the user's preference | |
| 95 */ | |
| 96 SECStatus | |
| 97 SECMIME_EnableCipher(long which, int on) | |
| 98 { | |
| 99 unsigned long mask; | |
| 100 | |
| 101 if (smime_newprefs == NULL || smime_prefs_complete) { | |
| 102 /* | |
| 103 * This is either the very first time, or we are starting over. | |
| 104 */ | |
| 105 smime_newprefs = (unsigned long*)PORT_ZAlloc (smime_symmetric_count | |
| 106 * sizeof(*smime_newprefs)); | |
| 107 if (smime_newprefs == NULL) | |
| 108 return SECFailure; | |
| 109 smime_current_pref_index = 0; | |
| 110 smime_prefs_complete = PR_FALSE; | |
| 111 } | |
| 112 | |
| 113 mask = which & CIPHER_FAMILYID_MASK; | |
| 114 if (mask == CIPHER_FAMILYID_MASK) { | |
| 115 /* | |
| 116 * This call signifies that all preferences have been set. | |
| 117 * Move "newprefs" over, after checking first whether or | |
| 118 * not the new ones are different from the old ones. | |
| 119 */ | |
| 120 if (smime_prefs != NULL) { | |
| 121 if (PORT_Memcmp (smime_prefs, smime_newprefs, | |
| 122 smime_symmetric_count * sizeof(*smime_prefs)) == 0) | |
| 123 smime_prefs_changed = PR_FALSE; | |
| 124 else | |
| 125 smime_prefs_changed = PR_TRUE; | |
| 126 PORT_Free (smime_prefs); | |
| 127 } | |
| 128 | |
| 129 smime_prefs = smime_newprefs; | |
| 130 smime_prefs_complete = PR_TRUE; | |
| 131 return SECSuccess; | |
| 132 } | |
| 133 | |
| 134 PORT_Assert (mask == CIPHER_FAMILYID_SMIME); | |
| 135 if (mask != CIPHER_FAMILYID_SMIME) { | |
| 136 /* XXX set an error! */ | |
| 137 return SECFailure; | |
| 138 } | |
| 139 | |
| 140 if (on) { | |
| 141 PORT_Assert (smime_current_pref_index < smime_symmetric_count); | |
| 142 if (smime_current_pref_index >= smime_symmetric_count) { | |
| 143 /* XXX set an error! */ | |
| 144 return SECFailure; | |
| 145 } | |
| 146 | |
| 147 smime_newprefs[smime_current_pref_index++] = which; | |
| 148 } | |
| 149 | |
| 150 return SECSuccess; | |
| 151 } | |
| 152 | |
| 153 | |
| 154 /* | |
| 155 * this function locally records the export policy | |
| 156 */ | |
| 157 SECStatus | |
| 158 SECMIME_SetPolicy(long which, int on) | |
| 159 { | |
| 160 unsigned long mask; | |
| 161 | |
| 162 PORT_Assert ((which & CIPHER_FAMILYID_MASK) == CIPHER_FAMILYID_SMIME); | |
| 163 if ((which & CIPHER_FAMILYID_MASK) != CIPHER_FAMILYID_SMIME) { | |
| 164 /* XXX set an error! */ | |
| 165 return SECFailure; | |
| 166 } | |
| 167 | |
| 168 which &= ~CIPHER_FAMILYID_MASK; | |
| 169 | |
| 170 PORT_Assert (which < 32); /* bits in the long */ | |
| 171 if (which >= 32) { | |
| 172 /* XXX set an error! */ | |
| 173 return SECFailure; | |
| 174 } | |
| 175 | |
| 176 mask = 1UL << which; | |
| 177 | |
| 178 if (on) { | |
| 179 smime_policy_bits |= mask; | |
| 180 } else { | |
| 181 smime_policy_bits &= ~mask; | |
| 182 } | |
| 183 | |
| 184 return SECSuccess; | |
| 185 } | |
| 186 | |
| 187 | |
| 188 /* | |
| 189 * Based on the given algorithm (including its parameters, in some cases!) | |
| 190 * and the given key (may or may not be inspected, depending on the | |
| 191 * algorithm), find the appropriate policy algorithm specification | |
| 192 * and return it. If no match can be made, -1 is returned. | |
| 193 */ | |
| 194 static long | |
| 195 smime_policy_algorithm (SECAlgorithmID *algid, PK11SymKey *key) | |
| 196 { | |
| 197 SECOidTag algtag; | |
| 198 | |
| 199 algtag = SECOID_GetAlgorithmTag (algid); | |
| 200 switch (algtag) { | |
| 201 case SEC_OID_RC2_CBC: | |
| 202 { | |
| 203 unsigned int keylen_bits; | |
| 204 | |
| 205 keylen_bits = PK11_GetKeyStrength (key, algid); | |
| 206 switch (keylen_bits) { | |
| 207 case 40: | |
| 208 return SMIME_RC2_CBC_40; | |
| 209 case 64: | |
| 210 return SMIME_RC2_CBC_64; | |
| 211 case 128: | |
| 212 return SMIME_RC2_CBC_128; | |
| 213 default: | |
| 214 break; | |
| 215 } | |
| 216 } | |
| 217 break; | |
| 218 case SEC_OID_DES_CBC: | |
| 219 return SMIME_DES_CBC_56; | |
| 220 case SEC_OID_DES_EDE3_CBC: | |
| 221 return SMIME_DES_EDE3_168; | |
| 222 #ifdef SMIME_DOES_RC5 | |
| 223 case SEC_OID_RC5_CBC_PAD: | |
| 224 PORT_Assert (0); /* XXX need to pull out parameters and match */ | |
| 225 break; | |
| 226 #endif | |
| 227 default: | |
| 228 break; | |
| 229 } | |
| 230 | |
| 231 return -1; | |
| 232 } | |
| 233 | |
| 234 | |
| 235 static PRBool | |
| 236 smime_cipher_allowed (unsigned long which) | |
| 237 { | |
| 238 unsigned long mask; | |
| 239 | |
| 240 which &= ~CIPHER_FAMILYID_MASK; | |
| 241 PORT_Assert (which < 32); /* bits per long (min) */ | |
| 242 if (which >= 32) | |
| 243 return PR_FALSE; | |
| 244 | |
| 245 mask = 1UL << which; | |
| 246 if ((mask & smime_policy_bits) == 0) | |
| 247 return PR_FALSE; | |
| 248 | |
| 249 return PR_TRUE; | |
| 250 } | |
| 251 | |
| 252 | |
| 253 PRBool | |
| 254 SECMIME_DecryptionAllowed(SECAlgorithmID *algid, PK11SymKey *key) | |
| 255 { | |
| 256 long which; | |
| 257 | |
| 258 which = smime_policy_algorithm (algid, key); | |
| 259 if (which < 0) | |
| 260 return PR_FALSE; | |
| 261 | |
| 262 return smime_cipher_allowed ((unsigned long)which); | |
| 263 } | |
| 264 | |
| 265 | |
| 266 /* | |
| 267 * Does the current policy allow *any* S/MIME encryption (or decryption)? | |
| 268 * | |
| 269 * This tells whether or not *any* S/MIME encryption can be done, | |
| 270 * according to policy. Callers may use this to do nicer user interface | |
| 271 * (say, greying out a checkbox so a user does not even try to encrypt | |
| 272 * a message when they are not allowed to) or for any reason they want | |
| 273 * to check whether S/MIME encryption (or decryption, for that matter) | |
| 274 * may be done. | |
| 275 * | |
| 276 * It takes no arguments. The return value is a simple boolean: | |
| 277 * PR_TRUE means encryption (or decryption) is *possible* | |
| 278 * (but may still fail due to other reasons, like because we cannot | |
| 279 * find all the necessary certs, etc.; PR_TRUE is *not* a guarantee) | |
| 280 * PR_FALSE means encryption (or decryption) is not permitted | |
| 281 * | |
| 282 * There are no errors from this routine. | |
| 283 */ | |
| 284 PRBool | |
| 285 SECMIME_EncryptionPossible (void) | |
| 286 { | |
| 287 if (smime_policy_bits != 0) | |
| 288 return PR_TRUE; | |
| 289 | |
| 290 return PR_FALSE; | |
| 291 } | |
| 292 | |
| 293 | |
| 294 /* | |
| 295 * XXX Would like the "parameters" field to be a SECItem *, but the | |
| 296 * encoder is having trouble with optional pointers to an ANY. Maybe | |
| 297 * once that is fixed, can change this back... | |
| 298 */ | |
| 299 typedef struct smime_capability_struct { | |
| 300 unsigned long cipher; /* local; not part of encoding */ | |
| 301 SECOidTag capIDTag; /* local; not part of encoding */ | |
| 302 SECItem capabilityID; | |
| 303 SECItem parameters; | |
| 304 } smime_capability; | |
| 305 | |
| 306 static const SEC_ASN1Template smime_capability_template[] = { | |
| 307 { SEC_ASN1_SEQUENCE, | |
| 308 0, NULL, sizeof(smime_capability) }, | |
| 309 { SEC_ASN1_OBJECT_ID, | |
| 310 offsetof(smime_capability,capabilityID), }, | |
| 311 { SEC_ASN1_OPTIONAL | SEC_ASN1_ANY, | |
| 312 offsetof(smime_capability,parameters), }, | |
| 313 { 0, } | |
| 314 }; | |
| 315 | |
| 316 static const SEC_ASN1Template smime_capabilities_template[] = { | |
| 317 { SEC_ASN1_SEQUENCE_OF, 0, smime_capability_template } | |
| 318 }; | |
| 319 | |
| 320 | |
| 321 | |
| 322 static void | |
| 323 smime_fill_capability (smime_capability *cap) | |
| 324 { | |
| 325 unsigned long cipher; | |
| 326 SECOidTag algtag; | |
| 327 int i; | |
| 328 | |
| 329 algtag = SECOID_FindOIDTag (&(cap->capabilityID)); | |
| 330 | |
| 331 for (i = 0; i < smime_symmetric_count; i++) { | |
| 332 if (smime_cipher_maps[i].algtag != algtag) | |
| 333 continue; | |
| 334 /* | |
| 335 * XXX If SECITEM_CompareItem allowed NULLs as arguments (comparing | |
| 336 * 2 NULLs as equal and NULL and non-NULL as not equal), we could | |
| 337 * use that here instead of all of the following comparison code. | |
| 338 */ | |
| 339 if (cap->parameters.data != NULL) { | |
| 340 if (smime_cipher_maps[i].parms == NULL) | |
| 341 continue; | |
| 342 if (cap->parameters.len != smime_cipher_maps[i].parms->len) | |
| 343 continue; | |
| 344 if (PORT_Memcmp (cap->parameters.data, | |
| 345 smime_cipher_maps[i].parms->data, | |
| 346 cap->parameters.len) == 0) | |
| 347 break; | |
| 348 } else if (smime_cipher_maps[i].parms == NULL) { | |
| 349 break; | |
| 350 } | |
| 351 } | |
| 352 | |
| 353 if (i == smime_symmetric_count) | |
| 354 cipher = 0; | |
| 355 else | |
| 356 cipher = smime_cipher_maps[i].cipher; | |
| 357 | |
| 358 cap->cipher = cipher; | |
| 359 cap->capIDTag = algtag; | |
| 360 } | |
| 361 | |
| 362 | |
| 363 static long | |
| 364 smime_choose_cipher (CERTCertificate *scert, CERTCertificate **rcerts) | |
| 365 { | |
| 366 PRArenaPool *poolp; | |
| 367 long chosen_cipher; | |
| 368 int *cipher_abilities; | |
| 369 int *cipher_votes; | |
| 370 int strong_mapi; | |
| 371 int rcount, mapi, max; | |
| 372 | |
| 373 if (smime_policy_bits == 0) { | |
| 374 PORT_SetError (SEC_ERROR_BAD_EXPORT_ALGORITHM); | |
| 375 return -1; | |
| 376 } | |
| 377 | |
| 378 chosen_cipher = SMIME_RC2_CBC_40; /* the default, LCD */ | |
| 379 | |
| 380 poolp = PORT_NewArena (1024); /* XXX what is right value? */ | |
| 381 if (poolp == NULL) | |
| 382 goto done; | |
| 383 | |
| 384 cipher_abilities = (int*)PORT_ArenaZAlloc (poolp, | |
| 385 smime_symmetric_count * sizeof(int)); | |
| 386 if (cipher_abilities == NULL) | |
| 387 goto done; | |
| 388 | |
| 389 cipher_votes = (int*)PORT_ArenaZAlloc (poolp, | |
| 390 smime_symmetric_count * sizeof(int)); | |
| 391 if (cipher_votes == NULL) | |
| 392 goto done; | |
| 393 | |
| 394 /* | |
| 395 * XXX Should have a #define somewhere which specifies default | |
| 396 * strong cipher. (Or better, a way to configure.) | |
| 397 */ | |
| 398 | |
| 399 /* Make triple-DES the strong cipher. */ | |
| 400 strong_mapi = smime_mapi_by_cipher (SMIME_DES_EDE3_168); | |
| 401 | |
| 402 PORT_Assert (strong_mapi >= 0); | |
| 403 | |
| 404 for (rcount = 0; rcerts[rcount] != NULL; rcount++) { | |
| 405 SECItem *profile; | |
| 406 smime_capability **caps; | |
| 407 int capi, pref; | |
| 408 SECStatus dstat; | |
| 409 | |
| 410 pref = smime_symmetric_count; | |
| 411 profile = CERT_FindSMimeProfile (rcerts[rcount]); | |
| 412 if (profile != NULL && profile->data != NULL && profile->len > 0) { | |
| 413 caps = NULL; | |
| 414 dstat = SEC_QuickDERDecodeItem (poolp, &caps, | |
| 415 smime_capabilities_template, | |
| 416 profile); | |
| 417 if (dstat == SECSuccess && caps != NULL) { | |
| 418 for (capi = 0; caps[capi] != NULL; capi++) { | |
| 419 smime_fill_capability (caps[capi]); | |
| 420 mapi = smime_mapi_by_cipher (caps[capi]->cipher); | |
| 421 if (mapi >= 0) { | |
| 422 cipher_abilities[mapi]++; | |
| 423 cipher_votes[mapi] += pref; | |
| 424 --pref; | |
| 425 } | |
| 426 } | |
| 427 } | |
| 428 } else { | |
| 429 SECKEYPublicKey *key; | |
| 430 unsigned int pklen_bits; | |
| 431 | |
| 432 /* | |
| 433 * XXX This is probably only good for RSA keys. What I would | |
| 434 * really like is a function to just say; Is the public key in | |
| 435 * this cert an export-length key? Then I would not have to | |
| 436 * know things like the value 512, or the kind of key, or what | |
| 437 * a subjectPublicKeyInfo is, etc. | |
| 438 */ | |
| 439 key = CERT_ExtractPublicKey (rcerts[rcount]); | |
| 440 if (key != NULL) { | |
| 441 pklen_bits = SECKEY_PublicKeyStrength (key) * 8; | |
| 442 SECKEY_DestroyPublicKey (key); | |
| 443 | |
| 444 if (pklen_bits > 512) { | |
| 445 cipher_abilities[strong_mapi]++; | |
| 446 cipher_votes[strong_mapi] += pref; | |
| 447 } | |
| 448 } | |
| 449 } | |
| 450 if (profile != NULL) | |
| 451 SECITEM_FreeItem (profile, PR_TRUE); | |
| 452 } | |
| 453 | |
| 454 max = 0; | |
| 455 for (mapi = 0; mapi < smime_symmetric_count; mapi++) { | |
| 456 if (cipher_abilities[mapi] != rcount) | |
| 457 continue; | |
| 458 if (! smime_cipher_allowed (smime_cipher_maps[mapi].cipher)) | |
| 459 continue; | |
| 460 if (cipher_votes[mapi] > max) { | |
| 461 chosen_cipher = smime_cipher_maps[mapi].cipher; | |
| 462 max = cipher_votes[mapi]; | |
| 463 } /* XXX else if a tie, let scert break it? */ | |
| 464 } | |
| 465 | |
| 466 done: | |
| 467 if (poolp != NULL) | |
| 468 PORT_FreeArena (poolp, PR_FALSE); | |
| 469 | |
| 470 return chosen_cipher; | |
| 471 } | |
| 472 | |
| 473 | |
| 474 /* | |
| 475 * XXX This is a hack for now to satisfy our current interface. | |
| 476 * Eventually, with more parameters needing to be specified, just | |
| 477 * looking up the keysize is not going to be sufficient. | |
| 478 */ | |
| 479 static int | |
| 480 smime_keysize_by_cipher (unsigned long which) | |
| 481 { | |
| 482 int keysize; | |
| 483 | |
| 484 switch (which) { | |
| 485 case SMIME_RC2_CBC_40: | |
| 486 keysize = 40; | |
| 487 break; | |
| 488 case SMIME_RC2_CBC_64: | |
| 489 keysize = 64; | |
| 490 break; | |
| 491 case SMIME_RC2_CBC_128: | |
| 492 keysize = 128; | |
| 493 break; | |
| 494 #ifdef SMIME_DOES_RC5 | |
| 495 case SMIME_RC5PAD_64_16_40: | |
| 496 case SMIME_RC5PAD_64_16_64: | |
| 497 case SMIME_RC5PAD_64_16_128: | |
| 498 /* XXX See comment above; keysize is not enough... */ | |
| 499 PORT_Assert (0); | |
| 500 PORT_SetError (SEC_ERROR_INVALID_ALGORITHM); | |
| 501 keysize = -1; | |
| 502 break; | |
| 503 #endif | |
| 504 case SMIME_DES_CBC_56: | |
| 505 case SMIME_DES_EDE3_168: | |
| 506 /* | |
| 507 * These are special; since the key size is fixed, we actually | |
| 508 * want to *avoid* specifying a key size. | |
| 509 */ | |
| 510 keysize = 0; | |
| 511 break; | |
| 512 default: | |
| 513 keysize = -1; | |
| 514 break; | |
| 515 } | |
| 516 | |
| 517 return keysize; | |
| 518 } | |
| 519 | |
| 520 | |
| 521 /* | |
| 522 * Start an S/MIME encrypting context. | |
| 523 * | |
| 524 * "scert" is the cert for the sender. It will be checked for validity. | |
| 525 * "rcerts" are the certs for the recipients. They will also be checked. | |
| 526 * | |
| 527 * "certdb" is the cert database to use for verifying the certs. | |
| 528 * It can be NULL if a default database is available (like in the client). | |
| 529 * | |
| 530 * This function already does all of the stuff specific to S/MIME protocol | |
| 531 * and local policy; the return value just needs to be passed to | |
| 532 * SEC_PKCS7Encode() or to SEC_PKCS7EncoderStart() to create the encoded data, | |
| 533 * and finally to SEC_PKCS7DestroyContentInfo(). | |
| 534 * | |
| 535 * An error results in a return value of NULL and an error set. | |
| 536 * (Retrieve specific errors via PORT_GetError()/XP_GetError().) | |
| 537 */ | |
| 538 SEC_PKCS7ContentInfo * | |
| 539 SECMIME_CreateEncrypted(CERTCertificate *scert, | |
| 540 CERTCertificate **rcerts, | |
| 541 CERTCertDBHandle *certdb, | |
| 542 SECKEYGetPasswordKey pwfn, | |
| 543 void *pwfn_arg) | |
| 544 { | |
| 545 SEC_PKCS7ContentInfo *cinfo; | |
| 546 long cipher; | |
| 547 SECOidTag encalg; | |
| 548 int keysize; | |
| 549 int mapi, rci; | |
| 550 | |
| 551 cipher = smime_choose_cipher (scert, rcerts); | |
| 552 if (cipher < 0) | |
| 553 return NULL; | |
| 554 | |
| 555 mapi = smime_mapi_by_cipher (cipher); | |
| 556 if (mapi < 0) | |
| 557 return NULL; | |
| 558 | |
| 559 /* | |
| 560 * XXX This is stretching it -- CreateEnvelopedData should probably | |
| 561 * take a cipher itself of some sort, because we cannot know what the | |
| 562 * future will bring in terms of parameters for each type of algorithm. | |
| 563 * For example, just an algorithm and keysize is *not* sufficient to | |
| 564 * fully specify the usage of RC5 (which also needs to know rounds and | |
| 565 * block size). Work this out into a better API! | |
| 566 */ | |
| 567 encalg = smime_cipher_maps[mapi].algtag; | |
| 568 keysize = smime_keysize_by_cipher (cipher); | |
| 569 if (keysize < 0) | |
| 570 return NULL; | |
| 571 | |
| 572 cinfo = SEC_PKCS7CreateEnvelopedData (scert, certUsageEmailRecipient, | |
| 573 certdb, encalg, keysize, | |
| 574 pwfn, pwfn_arg); | |
| 575 if (cinfo == NULL) | |
| 576 return NULL; | |
| 577 | |
| 578 for (rci = 0; rcerts[rci] != NULL; rci++) { | |
| 579 if (rcerts[rci] == scert) | |
| 580 continue; | |
| 581 if (SEC_PKCS7AddRecipient (cinfo, rcerts[rci], certUsageEmailRecipient, | |
| 582 NULL) != SECSuccess) { | |
| 583 SEC_PKCS7DestroyContentInfo (cinfo); | |
| 584 return NULL; | |
| 585 } | |
| 586 } | |
| 587 | |
| 588 return cinfo; | |
| 589 } | |
| 590 | |
| 591 | |
| 592 static smime_capability **smime_capabilities; | |
| 593 static SECItem *smime_encoded_caps; | |
| 594 | |
| 595 | |
| 596 static SECStatus | |
| 597 smime_init_caps (void) | |
| 598 { | |
| 599 smime_capability *cap; | |
| 600 smime_cipher_map *map; | |
| 601 SECOidData *oiddata; | |
| 602 SECStatus rv; | |
| 603 int i; | |
| 604 | |
| 605 if (smime_encoded_caps != NULL && (! smime_prefs_changed)) | |
| 606 return SECSuccess; | |
| 607 | |
| 608 if (smime_encoded_caps != NULL) { | |
| 609 SECITEM_FreeItem (smime_encoded_caps, PR_TRUE); | |
| 610 smime_encoded_caps = NULL; | |
| 611 } | |
| 612 | |
| 613 if (smime_capabilities == NULL) { | |
| 614 smime_capabilities = (smime_capability**)PORT_ZAlloc ( | |
| 615 (smime_symmetric_count + 1) | |
| 616 * sizeof(smime_capability *)); | |
| 617 if (smime_capabilities == NULL) | |
| 618 return SECFailure; | |
| 619 } | |
| 620 | |
| 621 rv = SECFailure; | |
| 622 | |
| 623 /* | |
| 624 The process of creating the encoded PKCS7 cipher capability list | |
| 625 involves two basic steps: | |
| 626 | |
| 627 (a) Convert our internal representation of cipher preferences | |
| 628 (smime_prefs) into an array containing cipher OIDs and | |
| 629 parameter data (smime_capabilities). This step is | |
| 630 performed here. | |
| 631 | |
| 632 (b) Encode, using ASN.1, the cipher information in | |
| 633 smime_capabilities, leaving the encoded result in | |
| 634 smime_encoded_caps. | |
| 635 | |
| 636 (In the process of performing (a), Lisa put in some optimizations | |
| 637 which allow us to avoid needlessly re-populating elements in | |
| 638 smime_capabilities as we walk through smime_prefs.) | |
| 639 */ | |
| 640 for (i = 0; i < smime_current_pref_index; i++) { | |
| 641 int mapi; | |
| 642 | |
| 643 /* Get the next cipher preference in smime_prefs. */ | |
| 644 mapi = smime_mapi_by_cipher (smime_prefs[i]); | |
| 645 if (mapi < 0) | |
| 646 break; | |
| 647 | |
| 648 /* Find the corresponding entry in the cipher map. */ | |
| 649 PORT_Assert (mapi < smime_symmetric_count); | |
| 650 map = &(smime_cipher_maps[mapi]); | |
| 651 | |
| 652 /* | |
| 653 * Convert the next preference found in smime_prefs into an | |
| 654 * smime_capability. | |
| 655 */ | |
| 656 | |
| 657 cap = smime_capabilities[i]; | |
| 658 if (cap == NULL) { | |
| 659 cap = (smime_capability*)PORT_ZAlloc (sizeof(smime_capability)); | |
| 660 if (cap == NULL) | |
| 661 break; | |
| 662 smime_capabilities[i] = cap; | |
| 663 } else if (cap->cipher == smime_prefs[i]) { | |
| 664 continue; /* no change to this one */ | |
| 665 } | |
| 666 | |
| 667 cap->capIDTag = map->algtag; | |
| 668 oiddata = SECOID_FindOIDByTag (map->algtag); | |
| 669 if (oiddata == NULL) | |
| 670 break; | |
| 671 | |
| 672 if (cap->capabilityID.data != NULL) { | |
| 673 SECITEM_FreeItem (&(cap->capabilityID), PR_FALSE); | |
| 674 cap->capabilityID.data = NULL; | |
| 675 cap->capabilityID.len = 0; | |
| 676 } | |
| 677 | |
| 678 rv = SECITEM_CopyItem (NULL, &(cap->capabilityID), &(oiddata->oid)); | |
| 679 if (rv != SECSuccess) | |
| 680 break; | |
| 681 | |
| 682 if (map->parms == NULL) { | |
| 683 cap->parameters.data = NULL; | |
| 684 cap->parameters.len = 0; | |
| 685 } else { | |
| 686 cap->parameters.data = map->parms->data; | |
| 687 cap->parameters.len = map->parms->len; | |
| 688 } | |
| 689 | |
| 690 cap->cipher = smime_prefs[i]; | |
| 691 } | |
| 692 | |
| 693 if (i != smime_current_pref_index) | |
| 694 return rv; | |
| 695 | |
| 696 while (i < smime_symmetric_count) { | |
| 697 cap = smime_capabilities[i]; | |
| 698 if (cap != NULL) { | |
| 699 SECITEM_FreeItem (&(cap->capabilityID), PR_FALSE); | |
| 700 PORT_Free (cap); | |
| 701 } | |
| 702 smime_capabilities[i] = NULL; | |
| 703 i++; | |
| 704 } | |
| 705 smime_capabilities[i] = NULL; | |
| 706 | |
| 707 smime_encoded_caps = SEC_ASN1EncodeItem (NULL, NULL, &smime_capabilities, | |
| 708 smime_capabilities_template); | |
| 709 if (smime_encoded_caps == NULL) | |
| 710 return SECFailure; | |
| 711 | |
| 712 return SECSuccess; | |
| 713 } | |
| 714 | |
| 715 | |
| 716 static SECStatus | |
| 717 smime_add_profile (CERTCertificate *cert, SEC_PKCS7ContentInfo *cinfo) | |
| 718 { | |
| 719 PORT_Assert (smime_prefs_complete); | |
| 720 if (! smime_prefs_complete) | |
| 721 return SECFailure; | |
| 722 | |
| 723 /* For that matter, if capabilities haven't been initialized yet, | |
| 724 do so now. */ | |
| 725 if (smime_encoded_caps == NULL || smime_prefs_changed) { | |
| 726 SECStatus rv; | |
| 727 | |
| 728 rv = smime_init_caps(); | |
| 729 if (rv != SECSuccess) | |
| 730 return rv; | |
| 731 | |
| 732 PORT_Assert (smime_encoded_caps != NULL); | |
| 733 } | |
| 734 | |
| 735 return SEC_PKCS7AddSignedAttribute (cinfo, SEC_OID_PKCS9_SMIME_CAPABILITIES, | |
| 736 smime_encoded_caps); | |
| 737 } | |
| 738 | |
| 739 | |
| 740 /* | |
| 741 * Start an S/MIME signing context. | |
| 742 * | |
| 743 * "scert" is the cert that will be used to sign the data. It will be | |
| 744 * checked for validity. | |
| 745 * | |
| 746 * "ecert" is the signer's encryption cert. If it is different from | |
| 747 * scert, then it will be included in the signed message so that the | |
| 748 * recipient can save it for future encryptions. | |
| 749 * | |
| 750 * "certdb" is the cert database to use for verifying the cert. | |
| 751 * It can be NULL if a default database is available (like in the client). | |
| 752 * | |
| 753 * "digestalg" names the digest algorithm (e.g. SEC_OID_SHA1). | |
| 754 * XXX There should be SECMIME functions for hashing, or the hashing should | |
| 755 * be built into this interface, which we would like because we would | |
| 756 * support more smartcards that way, and then this argument should go away.) | |
| 757 * | |
| 758 * "digest" is the actual digest of the data. It must be provided in | |
| 759 * the case of detached data or NULL if the content will be included. | |
| 760 * | |
| 761 * This function already does all of the stuff specific to S/MIME protocol | |
| 762 * and local policy; the return value just needs to be passed to | |
| 763 * SEC_PKCS7Encode() or to SEC_PKCS7EncoderStart() to create the encoded data, | |
| 764 * and finally to SEC_PKCS7DestroyContentInfo(). | |
| 765 * | |
| 766 * An error results in a return value of NULL and an error set. | |
| 767 * (Retrieve specific errors via PORT_GetError()/XP_GetError().) | |
| 768 */ | |
| 769 | |
| 770 SEC_PKCS7ContentInfo * | |
| 771 SECMIME_CreateSigned (CERTCertificate *scert, | |
| 772 CERTCertificate *ecert, | |
| 773 CERTCertDBHandle *certdb, | |
| 774 SECOidTag digestalg, | |
| 775 SECItem *digest, | |
| 776 SECKEYGetPasswordKey pwfn, | |
| 777 void *pwfn_arg) | |
| 778 { | |
| 779 SEC_PKCS7ContentInfo *cinfo; | |
| 780 SECStatus rv; | |
| 781 | |
| 782 /* See note in header comment above about digestalg. */ | |
| 783 /* Doesn't explain this. PORT_Assert (digestalg == SEC_OID_SHA1); */ | |
| 784 | |
| 785 cinfo = SEC_PKCS7CreateSignedData (scert, certUsageEmailSigner, | |
| 786 certdb, digestalg, digest, | |
| 787 pwfn, pwfn_arg); | |
| 788 if (cinfo == NULL) | |
| 789 return NULL; | |
| 790 | |
| 791 if (SEC_PKCS7IncludeCertChain (cinfo, NULL) != SECSuccess) { | |
| 792 SEC_PKCS7DestroyContentInfo (cinfo); | |
| 793 return NULL; | |
| 794 } | |
| 795 | |
| 796 /* if the encryption cert and the signing cert differ, then include | |
| 797 * the encryption cert too. | |
| 798 */ | |
| 799 /* it is ok to compare the pointers since we ref count, and the same | |
| 800 * cert will always have the same pointer | |
| 801 */ | |
| 802 if ( ( ecert != NULL ) && ( ecert != scert ) ) { | |
| 803 rv = SEC_PKCS7AddCertificate(cinfo, ecert); | |
| 804 if ( rv != SECSuccess ) { | |
| 805 SEC_PKCS7DestroyContentInfo (cinfo); | |
| 806 return NULL; | |
| 807 } | |
| 808 } | |
| 809 /* | |
| 810 * Add the signing time. But if it fails for some reason, | |
| 811 * may as well not give up altogether -- just assert. | |
| 812 */ | |
| 813 rv = SEC_PKCS7AddSigningTime (cinfo); | |
| 814 PORT_Assert (rv == SECSuccess); | |
| 815 | |
| 816 /* | |
| 817 * Add the email profile. Again, if it fails for some reason, | |
| 818 * may as well not give up altogether -- just assert. | |
| 819 */ | |
| 820 rv = smime_add_profile (ecert, cinfo); | |
| 821 PORT_Assert (rv == SECSuccess); | |
| 822 | |
| 823 return cinfo; | |
| 824 } | |
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