libsecurity_smime/lib/smimeutil.c

   1 /*
   2  * The contents of this file are subject to the Mozilla Public
   3  * License Version 1.1 (the "License"); you may not use this file
   4  * except in compliance with the License. You may obtain a copy of
   5  * the License at http://www.mozilla.org/MPL/
   6  *
   7  * Software distributed under the License is distributed on an "AS
   8  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
   9  * implied. See the License for the specific language governing
  10  * rights and limitations under the License.
  11  *
  12  * The Original Code is the Netscape security libraries.
  13  *
  14  * The Initial Developer of the Original Code is Netscape
  15  * Communications Corporation.  Portions created by Netscape are
  16  * Copyright (C) 1994-2000 Netscape Communications Corporation.  All
  17  * Rights Reserved.
  18  *
  19  * Contributor(s):
  20  *
  21  * Alternatively, the contents of this file may be used under the
  22  * terms of the GNU General Public License Version 2 or later (the
  23  * "GPL"), in which case the provisions of the GPL are applicable
  24  * instead of those above.  If you wish to allow use of your
  25  * version of this file only under the terms of the GPL and not to
  26  * allow others to use your version of this file under the MPL,
  27  * indicate your decision by deleting the provisions above and
  28  * replace them with the notice and other provisions required by
  29  * the GPL.  If you do not delete the provisions above, a recipient
  30  * may use your version of this file under either the MPL or the
  31  * GPL.
  32  */
  33
  34 /*
  35  * Stuff specific to S/MIME policy and interoperability.
  36  */
  37
  38 #include "cmslocal.h"
  39
  40 #include "secoid.h"
  41 #include "SecAsn1Item.h"
  42 #include "cert.h"
  43 #include "SecSMIMEPriv.h"
  44
  45 #include <security_asn1/secasn1.h>
  46 #include <security_asn1/secerr.h>
  47 #include <Security/SecSMIME.h>
  48 #include <Security/SecKeyPriv.h>
  49
  50 SEC_ASN1_MKSUB(CERT_IssuerAndSNTemplate)
  51 SEC_ASN1_MKSUB(SEC_OctetStringTemplate)
  52 SEC_ASN1_CHOOSER_DECLARE(CERT_IssuerAndSNTemplate)
  53
  54 /* various integer's ASN.1 encoding */
  55 static unsigned char asn1_int40[] = { SEC_ASN1_INTEGER, 0x01, 0x28 };
  56 static unsigned char asn1_int64[] = { SEC_ASN1_INTEGER, 0x01, 0x40 };
  57 static unsigned char asn1_int128[] = { SEC_ASN1_INTEGER, 0x02, 0x00, 0x80 };
  58
  59 /* RC2 algorithm parameters (used in smime_cipher_map) */
  60 static SecAsn1Item param_int40 = { sizeof(asn1_int40), asn1_int40 };
  61 static SecAsn1Item param_int64 = { sizeof(asn1_int64), asn1_int64 };
  62 static SecAsn1Item param_int128 = { sizeof(asn1_int128), asn1_int128 };
  63
  64 /*
  65  * XXX Would like the "parameters" field to be a SecAsn1Item * , but the
  66  * encoder is having trouble with optional pointers to an ANY.  Maybe
  67  * once that is fixed, can change this back...
  68  */
  69 typedef struct {
  70     SecAsn1Item capabilityID;
  71     SecAsn1Item parameters;
  72     long cipher;                /* optimization */
  73 } NSSSMIMECapability;
  74
  75 static const SecAsn1Template NSSSMIMECapabilityTemplate[] = {
  76     { SEC_ASN1_SEQUENCE,
  77           0, NULL, sizeof(NSSSMIMECapability) },
  78     { SEC_ASN1_OBJECT_ID,
  79           offsetof(NSSSMIMECapability,capabilityID), },
  80     { SEC_ASN1_OPTIONAL | SEC_ASN1_ANY,
  81           offsetof(NSSSMIMECapability,parameters), },
  82     { 0, }
  83 };
  84
  85 static const SecAsn1Template NSSSMIMECapabilitiesTemplate[] = {
  86     { SEC_ASN1_SEQUENCE_OF, 0, NSSSMIMECapabilityTemplate }
  87 };
  88
  89 /*
  90  * NSSSMIMEEncryptionKeyPreference - if we find one of these, it needs to prompt us
  91  *  to store this and only this certificate permanently for the sender email address.
  92  */
  93 typedef enum {
  94     NSSSMIMEEncryptionKeyPref_IssuerSN,
  95     NSSSMIMEEncryptionKeyPref_RKeyID,
  96     NSSSMIMEEncryptionKeyPref_SubjectKeyID
  97 } NSSSMIMEEncryptionKeyPrefSelector;
  98
  99 typedef struct {
 100     NSSSMIMEEncryptionKeyPrefSelector selector;
 101     union {
 102         SecCmsIssuerAndSN               *issuerAndSN;
 103         SecCmsRecipientKeyIdentifier    *recipientKeyID;
 104         SecAsn1Item *subjectKeyID;
 105     } id;
 106 } NSSSMIMEEncryptionKeyPreference;
 107
 108 extern const SecAsn1Template SecCmsRecipientKeyIdentifierTemplate[];
 109
 110 static const SecAsn1Template smime_encryptionkeypref_template[] = {
 111     { SEC_ASN1_CHOICE,
 112           offsetof(NSSSMIMEEncryptionKeyPreference,selector), NULL,
 113           sizeof(NSSSMIMEEncryptionKeyPreference) },
 114     { SEC_ASN1_POINTER | SEC_ASN1_CONTEXT_SPECIFIC | SEC_ASN1_XTRN | 0,
 115           offsetof(NSSSMIMEEncryptionKeyPreference,id.issuerAndSN),
 116           SEC_ASN1_SUB(SecCmsIssuerAndSNTemplate),
 117           NSSSMIMEEncryptionKeyPref_IssuerSN },
 118     { SEC_ASN1_POINTER | SEC_ASN1_CONTEXT_SPECIFIC | 1,
 119           offsetof(NSSSMIMEEncryptionKeyPreference,id.recipientKeyID),
 120           SecCmsRecipientKeyIdentifierTemplate,
 121           NSSSMIMEEncryptionKeyPref_IssuerSN },
 122     { SEC_ASN1_POINTER | SEC_ASN1_CONTEXT_SPECIFIC | SEC_ASN1_XTRN | 2,
 123           offsetof(NSSSMIMEEncryptionKeyPreference,id.subjectKeyID),
 124           SEC_ASN1_SUB(kSecAsn1OctetStringTemplate),
 125           NSSSMIMEEncryptionKeyPref_SubjectKeyID },
 126     { 0, }
 127 };
 128
 129 /* smime_cipher_map - map of SMIME symmetric "ciphers" to algtag & parameters */
 130 typedef struct {
 131     unsigned long cipher;
 132     SECOidTag algtag;
 133     SecAsn1Item *parms;
 134     Boolean enabled;    /* in the user's preferences */
 135     Boolean allowed;    /* per export policy */
 136 } smime_cipher_map_entry;
 137
 138 /* global: list of supported SMIME symmetric ciphers, ordered roughly by increasing strength */
 139 static smime_cipher_map_entry smime_cipher_map[] = {
 140 /*    cipher                    algtag                  parms           enabled  allowed */
 141 /*    ---------------------------------------------------------------------------------- */
 142     { SMIME_RC2_CBC_40,         SEC_OID_RC2_CBC,        &param_int40,   PR_FALSE, PR_FALSE },
 143     { SMIME_DES_CBC_56,         SEC_OID_DES_CBC,        NULL,                   PR_TRUE, PR_FALSE },
 144     { SMIME_RC2_CBC_64,         SEC_OID_RC2_CBC,        &param_int64,   PR_FALSE, PR_FALSE },
 145     { SMIME_RC2_CBC_128,        SEC_OID_RC2_CBC,        &param_int128,  PR_FALSE, PR_FALSE },
 146     { SMIME_DES_EDE3_168,       SEC_OID_DES_EDE3_CBC,   NULL,           PR_TRUE, PR_TRUE },
 147     { SMIME_AES_CBC_128,        SEC_OID_AES_128_CBC,    NULL,           PR_TRUE, PR_TRUE },
 148     { SMIME_AES_CBC_192,        SEC_OID_AES_192_CBC,    NULL,           PR_TRUE, PR_TRUE },
 149     { SMIME_AES_CBC_256,        SEC_OID_AES_256_CBC,    NULL,           PR_TRUE, PR_TRUE },
 150     { SMIME_FORTEZZA,           SEC_OID_FORTEZZA_SKIPJACK, NULL,        PR_TRUE, PR_TRUE }
 151 };
 152 static const int smime_cipher_map_count = sizeof(smime_cipher_map) / sizeof(smime_cipher_map_entry);
 153
 154 /*
 155  * smime_mapi_by_cipher - find index into smime_cipher_map by cipher
 156  */
 157 static int
 158 smime_mapi_by_cipher(unsigned long cipher)
 159 {
 160     int i;
 161
 162     for (i = 0; i < smime_cipher_map_count; i++) {
 163         if (smime_cipher_map[i].cipher == cipher)
 164             return i;   /* bingo */
 165     }
 166     return -1;          /* should not happen if we're consistent, right? */
 167 }
 168
 169 /*
 170  * NSS_SMIME_EnableCipher - this function locally records the user's preference
 171  */
 172 OSStatus
 173 SecSMIMEEnableCipher(unsigned long which, Boolean on)
 174 {
 175     unsigned long mask;
 176     int mapi;
 177
 178     mask = which & CIPHER_FAMILYID_MASK;
 179
 180     PORT_Assert (mask == CIPHER_FAMILYID_SMIME);
 181     if (mask != CIPHER_FAMILYID_SMIME)
 182         /* XXX set an error! */
 183         return SECFailure;
 184
 185     mapi = smime_mapi_by_cipher(which);
 186     if (mapi < 0)
 187         /* XXX set an error */
 188         return SECFailure;
 189
 190     /* do we try to turn on a forbidden cipher? */
 191     if (!smime_cipher_map[mapi].allowed && on) {
 192         PORT_SetError (SEC_ERROR_BAD_EXPORT_ALGORITHM);
 193         return SECFailure;
 194     }
 195
 196     smime_cipher_map[mapi].enabled = on;
 197
 198     return SECSuccess;
 199 }
 200
 201
 202 /*
 203  * this function locally records the export policy
 204  */
 205 OSStatus
 206 SecSMIMEAllowCipher(unsigned long which, Boolean on)
 207 {
 208     unsigned long mask;
 209     int mapi;
 210
 211     mask = which & CIPHER_FAMILYID_MASK;
 212
 213     PORT_Assert (mask == CIPHER_FAMILYID_SMIME);
 214     if (mask != CIPHER_FAMILYID_SMIME)
 215         /* XXX set an error! */
 216         return SECFailure;
 217
 218     mapi = smime_mapi_by_cipher(which);
 219     if (mapi < 0)
 220         /* XXX set an error */
 221         return SECFailure;
 222
 223     smime_cipher_map[mapi].allowed = on;
 224
 225     return SECSuccess;
 226 }
 227
 228 /*
 229  * Based on the given algorithm (including its parameters, in some cases!)
 230  * and the given key (may or may not be inspected, depending on the
 231  * algorithm), find the appropriate policy algorithm specification
 232  * and return it.  If no match can be made, -1 is returned.
 233  */
 234 static OSStatus
 235 nss_smime_get_cipher_for_alg_and_key(SECAlgorithmID *algid, SecSymmetricKeyRef key, unsigned long *cipher)
 236 {
 237     SECOidTag algtag;
 238     CFIndex keylen_bits;
 239     unsigned long c;
 240
 241     algtag = SECOID_GetAlgorithmTag(algid);
 242     switch (algtag) {
 243     case SEC_OID_RC2_CBC:
 244         keylen_bits = CFDataGetLength((CFDataRef)key) * 8;
 245         switch (keylen_bits) {
 246         case 40:
 247             c = SMIME_RC2_CBC_40;
 248             break;
 249         case 64:
 250             c = SMIME_RC2_CBC_64;
 251             break;
 252         case 128:
 253             c = SMIME_RC2_CBC_128;
 254             break;
 255         default:
 256             return SECFailure;
 257         }
 258         break;
 259     case SEC_OID_DES_CBC:
 260         c = SMIME_DES_CBC_56;
 261         break;
 262     case SEC_OID_FORTEZZA_SKIPJACK:
 263         c = SMIME_FORTEZZA;
 264         break;
 265     case SEC_OID_DES_EDE3_CBC:
 266         c = SMIME_DES_EDE3_168;
 267         break;
 268     case SEC_OID_AES_128_CBC:
 269         c = SMIME_AES_CBC_128;
 270         break;
 271     case SEC_OID_AES_192_CBC:
 272         c = SMIME_AES_CBC_192;
 273         break;
 274     case SEC_OID_AES_256_CBC:
 275         c = SMIME_AES_CBC_256;
 276         break;
 277     default:
 278         return SECFailure;
 279     }
 280     *cipher = c;
 281     return SECSuccess;
 282 }
 283
 284 static Boolean
 285 nss_smime_cipher_allowed(unsigned long which)
 286 {
 287     int mapi;
 288
 289     mapi = smime_mapi_by_cipher(which);
 290     if (mapi < 0)
 291         return PR_FALSE;
 292     return smime_cipher_map[mapi].allowed;
 293 }
 294
 295 Boolean
 296 SecSMIMEDecryptionAllowed(SECAlgorithmID *algid, SecSymmetricKeyRef key)
 297 {
 298     unsigned long which;
 299
 300     if (nss_smime_get_cipher_for_alg_and_key(algid, key, &which) != SECSuccess)
 301         return PR_FALSE;
 302
 303     return nss_smime_cipher_allowed(which);
 304 }
 305
 306
 307 /*
 308  * NSS_SMIME_EncryptionPossible - check if any encryption is allowed
 309  *
 310  * This tells whether or not *any* S/MIME encryption can be done,
 311  * according to policy.  Callers may use this to do nicer user interface
 312  * (say, greying out a checkbox so a user does not even try to encrypt
 313  * a message when they are not allowed to) or for any reason they want
 314  * to check whether S/MIME encryption (or decryption, for that matter)
 315  * may be done.
 316  *
 317  * It takes no arguments.  The return value is a simple boolean:
 318  *   PR_TRUE means encryption (or decryption) is *possible*
 319  *      (but may still fail due to other reasons, like because we cannot
 320  *      find all the necessary certs, etc.; PR_TRUE is *not* a guarantee)
 321  *   PR_FALSE means encryption (or decryption) is not permitted
 322  *
 323  * There are no errors from this routine.
 324  */
 325 Boolean
 326 SecSMIMEEncryptionPossible(void)
 327 {
 328     int i;
 329
 330     for (i = 0; i < smime_cipher_map_count; i++) {
 331         if (smime_cipher_map[i].allowed)
 332             return PR_TRUE;
 333     }
 334     return PR_FALSE;
 335 }
 336
 337
 338 static unsigned long
 339 nss_SMIME_FindCipherForSMIMECap(NSSSMIMECapability *cap)
 340 {
 341     int i;
 342     SECOidTag capIDTag;
 343
 344     /* we need the OIDTag here */
 345     capIDTag = SECOID_FindOIDTag(&(cap->capabilityID));
 346
 347     /* go over all the SMIME ciphers we know and see if we find a match */
 348     for (i = 0; i < smime_cipher_map_count; i++) {
 349         if (smime_cipher_map[i].algtag != capIDTag)
 350             continue;
 351         /*
 352          * XXX If SECITEM_CompareItem allowed NULLs as arguments (comparing
 353          * 2 NULLs as equal and NULL and non-NULL as not equal), we could
 354          * use that here instead of all of the following comparison code.
 355          */
 356         if (cap->parameters.Data == NULL && smime_cipher_map[i].parms == NULL)
 357             break;      /* both empty: bingo */
 358
 359         if (cap->parameters.Data != NULL && smime_cipher_map[i].parms != NULL &&
 360             cap->parameters.Length == smime_cipher_map[i].parms->Length &&
 361             PORT_Memcmp (cap->parameters.Data, smime_cipher_map[i].parms->Data,
 362                              cap->parameters.Length) == 0)
 363         {
 364             break;      /* both not empty, same length & equal content: bingo */
 365         }
 366     }
 367
 368     if (i == smime_cipher_map_count)
 369         return 0;                               /* no match found */
 370     else
 371         return smime_cipher_map[i].cipher;      /* match found, point to cipher */
 372 }
 373
 374 static int smime_keysize_by_cipher (unsigned long which);
 375
 376 /*
 377  * smime_choose_cipher - choose a cipher that works for all the recipients
 378  *
 379  * "scert"  - sender's certificate
 380  * "rcerts" - recipient's certificates
 381  */
 382 static long
 383 smime_choose_cipher(SecCertificateRef scert, SecCertificateRef *rcerts)
 384 {
 385     PRArenaPool *poolp;
 386     long cipher;
 387     long chosen_cipher;
 388     int *cipher_abilities;
 389     int *cipher_votes;
 390     int weak_mapi;
 391     int strong_mapi;
 392     int rcount, mapi, max, i;
 393 #if 1
 394     // @@@ We Don't support Fortezza yet.
 395     Boolean scert_is_fortezza  = PR_FALSE;
 396 #else
 397     Boolean scert_is_fortezza = (scert == NULL) ? PR_FALSE : PK11_FortezzaHasKEA(scert);
 398 #endif
 399
 400     chosen_cipher = SMIME_DES_CBC_56;           /* the default, LCD */
 401     weak_mapi = smime_mapi_by_cipher(chosen_cipher);
 402
 403     poolp = PORT_NewArena (1024);               /* XXX what is right value? */
 404     if (poolp == NULL)
 405         goto done;
 406
 407     cipher_abilities = (int *)PORT_ArenaZAlloc(poolp, smime_cipher_map_count * sizeof(int));
 408     cipher_votes     = (int *)PORT_ArenaZAlloc(poolp, smime_cipher_map_count * sizeof(int));
 409     if (cipher_votes == NULL || cipher_abilities == NULL)
 410         goto done;
 411
 412     /* If the user has the Fortezza preference turned on, make
 413      *  that the strong cipher. Otherwise, use triple-DES. */
 414     strong_mapi = smime_mapi_by_cipher (SMIME_DES_EDE3_168);
 415     if (scert_is_fortezza) {
 416         mapi = smime_mapi_by_cipher(SMIME_FORTEZZA);
 417         if (mapi >= 0 && smime_cipher_map[mapi].enabled)
 418             strong_mapi = mapi;
 419     }
 420
 421     /* walk all the recipient's certs */
 422     for (rcount = 0; rcerts[rcount] != NULL; rcount++) {
 423         SecAsn1Item *profile;
 424         NSSSMIMECapability **caps;
 425         int pref;
 426
 427         /* the first cipher that matches in the user's SMIME profile gets
 428          * "smime_cipher_map_count" votes; the next one gets "smime_cipher_map_count" - 1
 429          * and so on. If every cipher matches, the last one gets 1 (one) vote */
 430         pref = smime_cipher_map_count;
 431
 432         /* find recipient's SMIME profile */
 433         profile = CERT_FindSMimeProfile(rcerts[rcount]);
 434
 435         if (profile != NULL && profile->Data != NULL && profile->Length > 0) {
 436             /* we have a profile (still DER-encoded) */
 437             caps = NULL;
 438             /* decode it */
 439             if (SEC_ASN1DecodeItem(poolp, &caps, NSSSMIMECapabilitiesTemplate, profile) == SECSuccess &&
 440                     caps != NULL)
 441             {
 442                 /* walk the SMIME capabilities for this recipient */
 443                 for (i = 0; caps[i] != NULL; i++) {
 444                     cipher = nss_SMIME_FindCipherForSMIMECap(caps[i]);
 445                     mapi = smime_mapi_by_cipher(cipher);
 446                     if (mapi >= 0) {
 447                         /* found the cipher */
 448                         cipher_abilities[mapi]++;
 449                         cipher_votes[mapi] += pref;
 450                         --pref;
 451                     }
 452                 }
 453             }
 454         } else {
 455             /* no profile found - so we can only assume that the user can do
 456              * the mandatory algorithms which is RC2-40 (weak crypto) and 3DES (strong crypto) */
 457             SecPublicKeyRef key;
 458             size_t pklen_bits;
 459
 460             /*
 461              * if recipient's public key length is > 512, vote for a strong cipher
 462              * please not that the side effect of this is that if only one recipient
 463              * has an export-level public key, the strong cipher is disabled.
 464              *
 465              * XXX This is probably only good for RSA keys.  What I would
 466              * really like is a function to just say;  Is the public key in
 467              * this cert an export-length key?  Then I would not have to
 468              * know things like the value 512, or the kind of key, or what
 469              * a subjectPublicKeyInfo is, etc.
 470              */
 471             key = CERT_ExtractPublicKey(rcerts[rcount]);
 472             pklen_bits = 0;
 473             if (key != NULL) {
 474                 pklen_bits = SecKeyGetSize(key, kSecKeyKeySizeInBits);
 475                 SECKEY_DestroyPublicKey (key);
 476             }
 477
 478             if (pklen_bits > 512) {
 479                 /* cast votes for the strong algorithm */
 480                 cipher_abilities[strong_mapi]++;
 481                 cipher_votes[strong_mapi] += pref;
 482                 pref--;
 483             }
 484
 485             /* always cast (possibly less) votes for the weak algorithm */
 486             cipher_abilities[weak_mapi]++;
 487             cipher_votes[weak_mapi] += pref;
 488         }
 489         if (profile != NULL)
 490             SECITEM_FreeItem(profile, PR_TRUE);
 491     }
 492
 493     /* find cipher that is agreeable by all recipients and that has the most votes */
 494     max = 0;
 495     for (mapi = 0; mapi < smime_cipher_map_count; mapi++) {
 496         /* if not all of the recipients can do this, forget it */
 497         if (cipher_abilities[mapi] != rcount)
 498             continue;
 499         /* if cipher is not enabled or not allowed by policy, forget it */
 500         if (!smime_cipher_map[mapi].enabled || !smime_cipher_map[mapi].allowed)
 501             continue;
 502         /* if we're not doing fortezza, but the cipher is fortezza, forget it */
 503         if (!scert_is_fortezza  && (smime_cipher_map[mapi].cipher == SMIME_FORTEZZA))
 504             continue;
 505         /* now see if this one has more votes than the last best one */
 506         if (cipher_votes[mapi] >= max) {
 507             /* if equal number of votes, prefer the ones further down in the list */
 508             /* with the expectation that these are higher rated ciphers */
 509             chosen_cipher = smime_cipher_map[mapi].cipher;
 510             max = cipher_votes[mapi];
 511         }
 512     }
 513     /* if no common cipher was found, chosen_cipher stays at the default */
 514
 515 done:
 516     if (poolp != NULL)
 517         PORT_FreeArena (poolp, PR_FALSE);
 518
 519     if (smime_keysize_by_cipher(chosen_cipher) < 128) {
 520         /* you're going to use strong(er) crypto whether you like it or not */
 521         chosen_cipher = SMIME_DES_EDE3_168;
 522     }
 523     return chosen_cipher;
 524 }
 525
 526 /*
 527  * XXX This is a hack for now to satisfy our current interface.
 528  * Eventually, with more parameters needing to be specified, just
 529  * looking up the keysize is not going to be sufficient.
 530  */
 531 static int
 532 smime_keysize_by_cipher (unsigned long which)
 533 {
 534     int keysize;
 535
 536     switch (which) {
 537       case SMIME_RC2_CBC_40:
 538         keysize = 40;
 539         break;
 540       case SMIME_RC2_CBC_64:
 541         keysize = 64;
 542         break;
 543       case SMIME_RC2_CBC_128:
 544         keysize = 128;
 545         break;
 546       case SMIME_DES_CBC_56:
 547         keysize = 64;
 548         break;
 549       case SMIME_DES_EDE3_168:
 550         keysize = 192;
 551         break;
 552       case SMIME_FORTEZZA:
 553         /*
 554          * This is special; since the key size is fixed, we actually
 555          * want to *avoid* specifying a key size.
 556          */
 557         keysize = 0;
 558         break;
 559       default:
 560         keysize = -1;
 561         break;
 562     }
 563
 564     return keysize;
 565 }
 566
 567 /*
 568  * SecSMIMEFindBulkAlgForRecipients - find bulk algorithm suitable for all recipients
 569  *
 570  * it would be great for UI purposes if there would be a way to find out which recipients
 571  * prevented a strong cipher from being used...
 572  */
 573 OSStatus
 574 SecSMIMEFindBulkAlgForRecipients(SecCertificateRef *rcerts, SECOidTag *bulkalgtag, int *keysize)
 575 {
 576     unsigned long cipher;
 577     int mapi;
 578
 579     cipher = smime_choose_cipher(NULL, rcerts);
 580     mapi = smime_mapi_by_cipher(cipher);
 581     if (mapi < 0) {
 582         return SECFailure;
 583     }
 584
 585     *bulkalgtag = smime_cipher_map[mapi].algtag;
 586     *keysize = smime_keysize_by_cipher(smime_cipher_map[mapi].cipher);
 587
 588     return SECSuccess;
 589 }
 590
 591 /*
 592  * SecSMIMECreateSMIMECapabilities - get S/MIME capabilities for this instance of NSS
 593  *
 594  * scans the list of allowed and enabled ciphers and construct a PKCS9-compliant
 595  * S/MIME capabilities attribute value.
 596  *
 597  * XXX Please note that, in contradiction to RFC2633 2.5.2, the capabilities only include
 598  * symmetric ciphers, NO signature algorithms or key encipherment algorithms.
 599  *
 600  * "poolp" - arena pool to create the S/MIME capabilities data on
 601  * "dest" - SecAsn1Item to put the data in
 602  * "includeFortezzaCiphers" - PR_TRUE if fortezza ciphers should be included
 603  */
 604 OSStatus
 605 SecSMIMECreateSMIMECapabilities(PLArenaPool *poolp, SecAsn1Item *dest, Boolean includeFortezzaCiphers)
 606 {
 607     NSSSMIMECapability *cap;
 608     NSSSMIMECapability **smime_capabilities;
 609     smime_cipher_map_entry *map;
 610     SECOidData *oiddata;
 611     SecAsn1Item *dummy;
 612     int i, capIndex;
 613
 614     /* if we have an old NSSSMIMECapability array, we'll reuse it (has the right size) */
 615     /* smime_cipher_map_count + 1 is an upper bound - we might end up with less */
 616     smime_capabilities = (NSSSMIMECapability **)PORT_ZAlloc((smime_cipher_map_count + 1)
 617                                       * sizeof(NSSSMIMECapability *));
 618     if (smime_capabilities == NULL)
 619         return SECFailure;
 620
 621     capIndex = 0;
 622
 623     /* Add all the symmetric ciphers
 624      * We walk the cipher list backwards, as it is ordered by increasing strength,
 625      * we prefer the stronger cipher over a weaker one, and we have to list the
 626      * preferred algorithm first */
 627     for (i = smime_cipher_map_count - 1; i >= 0; i--) {
 628         /* Find the corresponding entry in the cipher map. */
 629         map = &(smime_cipher_map[i]);
 630         if (!map->enabled)
 631             continue;
 632
 633         /* If we're using a non-Fortezza cert, only advertise non-Fortezza
 634            capabilities. (We advertise all capabilities if we have a
 635            Fortezza cert.) */
 636         if ((!includeFortezzaCiphers) && (map->cipher == SMIME_FORTEZZA))
 637             continue;
 638
 639         /* get next SMIME capability */
 640         cap = (NSSSMIMECapability *)PORT_ZAlloc(sizeof(NSSSMIMECapability));
 641         if (cap == NULL)
 642             break;
 643         smime_capabilities[capIndex++] = cap;
 644
 645         oiddata = SECOID_FindOIDByTag(map->algtag);
 646         if (oiddata == NULL)
 647             break;
 648
 649         cap->capabilityID.Data = oiddata->oid.Data;
 650         cap->capabilityID.Length = oiddata->oid.Length;
 651         cap->parameters.Data = map->parms ? map->parms->Data : NULL;
 652         cap->parameters.Length = map->parms ? map->parms->Length : 0;
 653         cap->cipher = smime_cipher_map[i].cipher;
 654     }
 655
 656     /* XXX add signature algorithms */
 657     /* XXX add key encipherment algorithms */
 658
 659     smime_capabilities[capIndex] = NULL;        /* last one - now encode */
 660     dummy = SEC_ASN1EncodeItem(poolp, dest, &smime_capabilities, NSSSMIMECapabilitiesTemplate);
 661
 662     /* now that we have the proper encoded SMIMECapabilities (or not),
 663      * free the work data */
 664     for (i = 0; smime_capabilities[i] != NULL; i++)
 665         PORT_Free(smime_capabilities[i]);
 666     PORT_Free(smime_capabilities);
 667
 668     return (dummy == NULL) ? SECFailure : SECSuccess;
 669 }
 670
 671 /*
 672  * SecSMIMECreateSMIMEEncKeyPrefs - create S/MIME encryption key preferences attr value
 673  *
 674  * "poolp" - arena pool to create the attr value on
 675  * "dest" - SecAsn1Item to put the data in
 676  * "cert" - certificate that should be marked as preferred encryption key
 677  *          cert is expected to have been verified for EmailRecipient usage.
 678  */
 679 OSStatus
 680 SecSMIMECreateSMIMEEncKeyPrefs(PLArenaPool *poolp, SecAsn1Item *dest, SecCertificateRef cert)
 681 {
 682     NSSSMIMEEncryptionKeyPreference ekp;
 683     SecAsn1Item *dummy = NULL;
 684     PLArenaPool *tmppoolp = NULL;
 685
 686     if (cert == NULL)
 687         goto loser;
 688
 689     tmppoolp = PORT_NewArena(1024);
 690     if (tmppoolp == NULL)
 691         goto loser;
 692
 693     /* XXX hardcoded IssuerSN choice for now */
 694     ekp.selector = NSSSMIMEEncryptionKeyPref_IssuerSN;
 695     ekp.id.issuerAndSN = CERT_GetCertIssuerAndSN(tmppoolp, cert);
 696     if (ekp.id.issuerAndSN == NULL)
 697         goto loser;
 698
 699     dummy = SEC_ASN1EncodeItem(poolp, dest, &ekp, smime_encryptionkeypref_template);
 700
 701 loser:
 702     if (tmppoolp) PORT_FreeArena(tmppoolp, PR_FALSE);
 703
 704     return (dummy == NULL) ? SECFailure : SECSuccess;
 705 }
 706
 707 /*
 708  * SecSMIMECreateSMIMEEncKeyPrefs - create S/MIME encryption key preferences attr value using MS oid
 709  *
 710  * "poolp" - arena pool to create the attr value on
 711  * "dest" - SecAsn1Item to put the data in
 712  * "cert" - certificate that should be marked as preferred encryption key
 713  *          cert is expected to have been verified for EmailRecipient usage.
 714  */
 715 OSStatus
 716 SecSMIMECreateMSSMIMEEncKeyPrefs(PLArenaPool *poolp, SecAsn1Item *dest, SecCertificateRef cert)
 717 {
 718     SecAsn1Item *dummy = NULL;
 719     PLArenaPool *tmppoolp = NULL;
 720     SecCmsIssuerAndSN *isn;
 721
 722     if (cert == NULL)
 723         goto loser;
 724
 725     tmppoolp = PORT_NewArena(1024);
 726     if (tmppoolp == NULL)
 727         goto loser;
 728
 729     isn = CERT_GetCertIssuerAndSN(tmppoolp, cert);
 730     if (isn == NULL)
 731         goto loser;
 732
 733     dummy = SEC_ASN1EncodeItem(poolp, dest, isn, SEC_ASN1_GET(SecCmsIssuerAndSNTemplate));
 734
 735 loser:
 736     if (tmppoolp) PORT_FreeArena(tmppoolp, PR_FALSE);
 737
 738     return (dummy == NULL) ? SECFailure : SECSuccess;
 739 }
 740
 741 #if 0
 742 /*
 743  * SecSMIMEGetCertFromEncryptionKeyPreference -
 744  *                              find cert marked by EncryptionKeyPreference attribute
 745  *
 746  * "keychainOrArray" - handle for the cert database to look in
 747  * "DERekp" - DER-encoded value of S/MIME Encryption Key Preference attribute
 748  *
 749  * if certificate is supposed to be found among the message's included certificates,
 750  * they are assumed to have been imported already.
 751  */
 752 SecCertificateRef
 753 SecSMIMEGetCertFromEncryptionKeyPreference(SecKeychainRef keychainOrArray, SecAsn1Item *DERekp)
 754 {
 755     PLArenaPool *tmppoolp = NULL;
 756     SecCertificateRef cert = NULL;
 757     NSSSMIMEEncryptionKeyPreference ekp;
 758
 759     tmppoolp = PORT_NewArena(1024);
 760     if (tmppoolp == NULL)
 761         return NULL;
 762
 763     /* decode DERekp */
 764     if (SEC_ASN1DecodeItem(tmppoolp, &ekp, smime_encryptionkeypref_template, DERekp) != SECSuccess)
 765         goto loser;
 766
 767     /* find cert */
 768     switch (ekp.selector) {
 769     case NSSSMIMEEncryptionKeyPref_IssuerSN:
 770         cert = CERT_FindCertByIssuerAndSN(keychainOrArray, ekp.id.issuerAndSN);
 771         break;
 772     case NSSSMIMEEncryptionKeyPref_RKeyID:
 773     case NSSSMIMEEncryptionKeyPref_SubjectKeyID:
 774         /* XXX not supported yet - we need to be able to look up certs by SubjectKeyID */
 775         break;
 776     default:
 777         PORT_Assert(0);
 778     }
 779 loser:
 780     if (tmppoolp) PORT_FreeArena(tmppoolp, PR_FALSE);
 781
 782     return cert;
 783 }
 784 #endif
 785
 786 #if 0
 787 extern const char __nss_smime_rcsid[];
 788 extern const char __nss_smime_sccsid[];
 789
 790 Boolean
 791 NSSSMIME_VersionCheck(const char *importedVersion)
 792 {
 793 #if 1
 794     return PR_TRUE;
 795 #else
 796     /*
 797      * This is the secret handshake algorithm.
 798      *
 799      * This release has a simple version compatibility
 800      * check algorithm.  This release is not backward
 801      * compatible with previous major releases.  It is
 802      * not compatible with future major, minor, or
 803      * patch releases.
 804      */
 805     volatile char c; /* force a reference that won't get optimized away */
 806
 807     c = __nss_smime_rcsid[0] + __nss_smime_sccsid[0];
 808
 809     return NSS_VersionCheck(importedVersion);
 810 #endif
 811 }
 812 #endif /* 0 */
 813