OSX/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 "secitem.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 CSSM_DATA param_int40 = { sizeof(asn1_int40), asn1_int40 };
  61 static CSSM_DATA param_int64 = { sizeof(asn1_int64), asn1_int64 };
  62 static CSSM_DATA param_int128 = { sizeof(asn1_int128), asn1_int128 };
  63
  64 /*
  65  * XXX Would like the "parameters" field to be a CSSM_DATA_PTR , 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     CSSM_DATA capabilityID;
  71     CSSM_DATA 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         CSSM_DATA_PTR 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           SEC_ASN1_SUB(SecCmsRecipientKeyIdentifierTemplate),
 121           NSSSMIMEEncryptionKeyPref_RKeyID },
 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     CSSM_DATA_PTR 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_TRUE },
 143     { SMIME_DES_CBC_56,         SEC_OID_DES_CBC,        NULL,           PR_FALSE,PR_TRUE },
 144     { SMIME_RC2_CBC_64,         SEC_OID_RC2_CBC,        &param_int64,   PR_FALSE,PR_TRUE },
 145     { SMIME_RC2_CBC_128,        SEC_OID_RC2_CBC,        &param_int128,  PR_TRUE, PR_TRUE },
 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_FORTEZZA,           SEC_OID_FORTEZZA_SKIPJACK, NULL,        PR_FALSE, PR_TRUE }
 149 };
 150 static const int smime_cipher_map_count = sizeof(smime_cipher_map) / sizeof(smime_cipher_map_entry);
 151
 152 /*
 153  * smime_mapi_by_cipher - find index into smime_cipher_map by cipher
 154  */
 155 static int
 156 smime_mapi_by_cipher(unsigned long cipher)
 157 {
 158     int i;
 159
 160     for (i = 0; i < smime_cipher_map_count; i++) {
 161         if (smime_cipher_map[i].cipher == cipher)
 162             return i;   /* bingo */
 163     }
 164     return -1;          /* should not happen if we're consistent, right? */
 165 }
 166
 167 /*
 168  * NSS_SMIME_EnableCipher - this function locally records the user's preference
 169  */
 170 OSStatus
 171 SecSMIMEEnableCipher(uint32 which, Boolean on)
 172 {
 173     unsigned long mask;
 174     int mapi;
 175
 176     mask = which & CIPHER_FAMILYID_MASK;
 177
 178     PORT_Assert (mask == CIPHER_FAMILYID_SMIME);
 179     if (mask != CIPHER_FAMILYID_SMIME)
 180         /* XXX set an error! */
 181         return SECFailure;
 182
 183     mapi = smime_mapi_by_cipher(which);
 184     if (mapi < 0)
 185         /* XXX set an error */
 186         return SECFailure;
 187
 188     /* do we try to turn on a forbidden cipher? */
 189     if (!smime_cipher_map[mapi].allowed && on) {
 190         PORT_SetError (SEC_ERROR_BAD_EXPORT_ALGORITHM);
 191         return SECFailure;
 192     }
 193
 194     smime_cipher_map[mapi].enabled = on;
 195
 196     return SECSuccess;
 197 }
 198
 199
 200 /*
 201  * this function locally records the export policy
 202  */
 203 OSStatus
 204 SecSMIMEAllowCipher(uint32 which, Boolean on)
 205 {
 206     unsigned long mask;
 207     int mapi;
 208
 209     mask = which & CIPHER_FAMILYID_MASK;
 210
 211     PORT_Assert (mask == CIPHER_FAMILYID_SMIME);
 212     if (mask != CIPHER_FAMILYID_SMIME)
 213         /* XXX set an error! */
 214         return SECFailure;
 215
 216     mapi = smime_mapi_by_cipher(which);
 217     if (mapi < 0)
 218         /* XXX set an error */
 219         return SECFailure;
 220
 221     smime_cipher_map[mapi].allowed = on;
 222
 223     return SECSuccess;
 224 }
 225
 226 /*
 227  * Based on the given algorithm (including its parameters, in some cases!)
 228  * and the given key (may or may not be inspected, depending on the
 229  * algorithm), find the appropriate policy algorithm specification
 230  * and return it.  If no match can be made, -1 is returned.
 231  */
 232 static OSStatus
 233 nss_smime_get_cipher_for_alg_and_key(SECAlgorithmID *algid, SecSymmetricKeyRef key, unsigned long *cipher)
 234 {
 235     SECOidTag algtag;
 236     unsigned int keylen_bits;
 237     unsigned long c;
 238
 239     algtag = SECOID_GetAlgorithmTag(algid);
 240     switch (algtag) {
 241     case SEC_OID_RC2_CBC:
 242         if (SecKeyGetStrengthInBits(key, algid, &keylen_bits))
 243             return SECFailure;
 244         switch (keylen_bits) {
 245         case 40:
 246             c = SMIME_RC2_CBC_40;
 247             break;
 248         case 64:
 249             c = SMIME_RC2_CBC_64;
 250             break;
 251         case 128:
 252             c = SMIME_RC2_CBC_128;
 253             break;
 254         default:
 255             return SECFailure;
 256         }
 257         break;
 258     case SEC_OID_DES_CBC:
 259         c = SMIME_DES_CBC_56;
 260         break;
 261     case SEC_OID_DES_EDE3_CBC:
 262         c = SMIME_DES_EDE3_168;
 263         break;
 264     case SEC_OID_AES_128_CBC:
 265         c = SMIME_AES_CBC_128;
 266         break;
 267     case SEC_OID_FORTEZZA_SKIPJACK:
 268         c = SMIME_FORTEZZA;
 269         break;
 270     default:
 271         return SECFailure;
 272     }
 273     *cipher = c;
 274     return SECSuccess;
 275 }
 276
 277 static Boolean
 278 nss_smime_cipher_allowed(unsigned long which)
 279 {
 280     int mapi;
 281
 282     mapi = smime_mapi_by_cipher(which);
 283     if (mapi < 0)
 284         return PR_FALSE;
 285     return smime_cipher_map[mapi].allowed;
 286 }
 287
 288 Boolean
 289 SecSMIMEDecryptionAllowed(SECAlgorithmID *algid, SecSymmetricKeyRef key)
 290 {
 291     unsigned long which;
 292
 293     if (nss_smime_get_cipher_for_alg_and_key(algid, key, &which) != SECSuccess)
 294         return PR_FALSE;
 295
 296     return nss_smime_cipher_allowed(which);
 297 }
 298
 299
 300 /*
 301  * NSS_SMIME_EncryptionPossible - check if any encryption is allowed
 302  *
 303  * This tells whether or not *any* S/MIME encryption can be done,
 304  * according to policy.  Callers may use this to do nicer user interface
 305  * (say, greying out a checkbox so a user does not even try to encrypt
 306  * a message when they are not allowed to) or for any reason they want
 307  * to check whether S/MIME encryption (or decryption, for that matter)
 308  * may be done.
 309  *
 310  * It takes no arguments.  The return value is a simple boolean:
 311  *   PR_TRUE means encryption (or decryption) is *possible*
 312  *      (but may still fail due to other reasons, like because we cannot
 313  *      find all the necessary certs, etc.; PR_TRUE is *not* a guarantee)
 314  *   PR_FALSE means encryption (or decryption) is not permitted
 315  *
 316  * There are no errors from this routine.
 317  */
 318 Boolean
 319 SecSMIMEEncryptionPossible(void)
 320 {
 321     int i;
 322
 323     for (i = 0; i < smime_cipher_map_count; i++) {
 324         if (smime_cipher_map[i].allowed)
 325             return PR_TRUE;
 326     }
 327     return PR_FALSE;
 328 }
 329
 330
 331 static unsigned long
 332 nss_SMIME_FindCipherForSMIMECap(NSSSMIMECapability *cap)
 333 {
 334     int i;
 335     SECOidTag capIDTag;
 336
 337     /* we need the OIDTag here */
 338     capIDTag = SECOID_FindOIDTag(&(cap->capabilityID));
 339
 340     /* go over all the SMIME ciphers we know and see if we find a match */
 341     for (i = 0; i < smime_cipher_map_count; i++) {
 342         if (smime_cipher_map[i].algtag != capIDTag)
 343             continue;
 344         /*
 345          * XXX If SECITEM_CompareItem allowed NULLs as arguments (comparing
 346          * 2 NULLs as equal and NULL and non-NULL as not equal), we could
 347          * use that here instead of all of the following comparison code.
 348          */
 349         if (cap->parameters.Data == NULL && smime_cipher_map[i].parms == NULL)
 350             break;      /* both empty: bingo */
 351
 352         if (cap->parameters.Data != NULL && smime_cipher_map[i].parms != NULL &&
 353             cap->parameters.Length == smime_cipher_map[i].parms->Length &&
 354             PORT_Memcmp (cap->parameters.Data, smime_cipher_map[i].parms->Data,
 355                              cap->parameters.Length) == 0)
 356         {
 357             break;      /* both not empty, same length & equal content: bingo */
 358         }
 359     }
 360
 361     if (i == smime_cipher_map_count)
 362         return 0;                               /* no match found */
 363     else
 364         return smime_cipher_map[i].cipher;      /* match found, point to cipher */
 365 }
 366
 367 static int smime_keysize_by_cipher (unsigned long which);
 368
 369 /*
 370  * smime_choose_cipher - choose a cipher that works for all the recipients
 371  *
 372  * "scert"  - sender's certificate
 373  * "rcerts" - recipient's certificates
 374  */
 375 static long
 376 smime_choose_cipher(SecCertificateRef scert, SecCertificateRef *rcerts)
 377 {
 378     PRArenaPool *poolp;
 379     long cipher;
 380     long chosen_cipher = SMIME_DES_EDE3_168;
 381     int *cipher_abilities;
 382     int *cipher_votes;
 383     int strong_mapi;
 384     int rcount, mapi, max, i;
 385 #if 1
 386     // @@@ We Don't support Fortezza yet.
 387     Boolean scert_is_fortezza  = PR_FALSE;
 388 #else
 389     Boolean scert_is_fortezza = (scert == NULL) ? PR_FALSE : PK11_FortezzaHasKEA(scert);
 390 #endif
 391
 392     poolp = PORT_NewArena (1024);               /* XXX what is right value? */
 393     if (poolp == NULL)
 394         goto done;
 395
 396     cipher_abilities = (int *)PORT_ArenaZAlloc(poolp, smime_cipher_map_count * sizeof(int));
 397     cipher_votes     = (int *)PORT_ArenaZAlloc(poolp, smime_cipher_map_count * sizeof(int));
 398     if (cipher_votes == NULL || cipher_abilities == NULL)
 399         goto done;
 400
 401     /* If the user has the Fortezza preference turned on, make
 402      *  that the strong cipher. Otherwise, use triple-DES. */
 403     strong_mapi = smime_mapi_by_cipher (SMIME_DES_EDE3_168);
 404     if (scert_is_fortezza) {
 405         mapi = smime_mapi_by_cipher(SMIME_FORTEZZA);
 406         if (mapi >= 0 && smime_cipher_map[mapi].enabled)
 407             strong_mapi = mapi;
 408     }
 409
 410     /* walk all the recipient's certs */
 411     for (rcount = 0; rcerts[rcount] != NULL; rcount++) {
 412         CSSM_DATA_PTR profile;
 413         NSSSMIMECapability **caps;
 414         int pref;
 415
 416         /* the first cipher that matches in the user's SMIME profile gets
 417          * "smime_cipher_map_count" votes; the next one gets "smime_cipher_map_count" - 1
 418          * and so on. If every cipher matches, the last one gets 1 (one) vote */
 419         pref = smime_cipher_map_count;
 420
 421         /* find recipient's SMIME profile */
 422         profile = CERT_FindSMimeProfile(rcerts[rcount]);
 423
 424         if (profile != NULL && profile->Data != NULL && profile->Length > 0) {
 425             /* we have a profile (still DER-encoded) */
 426             caps = NULL;
 427             /* decode it */
 428             if (SEC_ASN1DecodeItem(poolp, &caps, NSSSMIMECapabilitiesTemplate, profile) == SECSuccess &&
 429                     caps != NULL)
 430             {
 431                 /* walk the SMIME capabilities for this recipient */
 432                 for (i = 0; caps[i] != NULL; i++) {
 433                     cipher = nss_SMIME_FindCipherForSMIMECap(caps[i]);
 434                     mapi = smime_mapi_by_cipher(cipher);
 435                     if (mapi >= 0) {
 436                         /* found the cipher */
 437                         cipher_abilities[mapi]++;
 438                         cipher_votes[mapi] += pref;
 439                         --pref;
 440                     }
 441                 }
 442             }
 443         } else {
 444             /* cast votes for the strong algorithm */
 445             cipher_abilities[strong_mapi]++;
 446             cipher_votes[strong_mapi] += pref;
 447             pref--;
 448         }
 449         if (profile != NULL)
 450             SECITEM_FreeItem(profile, PR_TRUE);
 451     }
 452
 453     /* find cipher that is agreeable by all recipients and that has the most votes */
 454     max = 0;
 455     for (mapi = 0; mapi < smime_cipher_map_count; mapi++) {
 456         /* if not all of the recipients can do this, forget it */
 457         if (cipher_abilities[mapi] != rcount)
 458             continue;
 459         /* if cipher is not enabled or not allowed by policy, forget it */
 460         if (!smime_cipher_map[mapi].enabled || !smime_cipher_map[mapi].allowed)
 461             continue;
 462         /* if we're not doing fortezza, but the cipher is fortezza, forget it */
 463         if (!scert_is_fortezza  && (smime_cipher_map[mapi].cipher == SMIME_FORTEZZA))
 464             continue;
 465         /* now see if this one has more votes than the last best one */
 466         if (cipher_votes[mapi] >= max) {
 467             /* if equal number of votes, prefer the ones further down in the list */
 468             /* with the expectation that these are higher rated ciphers */
 469             chosen_cipher = smime_cipher_map[mapi].cipher;
 470             max = cipher_votes[mapi];
 471         }
 472     }
 473     /* if no common cipher was found, chosen_cipher stays at the default */
 474
 475 done:
 476     if (poolp != NULL)
 477         PORT_FreeArena (poolp, PR_FALSE);
 478
 479     if (smime_keysize_by_cipher(chosen_cipher) < 128) {
 480         /* you're going to use strong(er) crypto whether you like it or not */
 481         chosen_cipher = SMIME_DES_EDE3_168;
 482     }
 483     return chosen_cipher;
 484 }
 485
 486 /*
 487  * XXX This is a hack for now to satisfy our current interface.
 488  * Eventually, with more parameters needing to be specified, just
 489  * looking up the keysize is not going to be sufficient.
 490  */
 491 static int
 492 smime_keysize_by_cipher (unsigned long which)
 493 {
 494     int keysize;
 495
 496     switch (which) {
 497       case SMIME_RC2_CBC_40:
 498         keysize = 40;
 499         break;
 500       case SMIME_RC2_CBC_64:
 501         keysize = 64;
 502         break;
 503       case SMIME_RC2_CBC_128:
 504       case SMIME_AES_CBC_128:
 505         keysize = 128;
 506         break;
 507       case SMIME_DES_CBC_56:
 508         keysize = 64;
 509         break;
 510       case SMIME_DES_EDE3_168:
 511         keysize = 192;
 512         break;
 513       case SMIME_FORTEZZA:
 514         /*
 515          * This is special; since the key size is fixed, we actually
 516          * want to *avoid* specifying a key size.
 517          */
 518         keysize = 0;
 519         break;
 520       default:
 521         keysize = -1;
 522         break;
 523     }
 524
 525     return keysize;
 526 }
 527
 528 /*
 529  * SecSMIMEFindBulkAlgForRecipients - find bulk algorithm suitable for all recipients
 530  *
 531  * it would be great for UI purposes if there would be a way to find out which recipients
 532  * prevented a strong cipher from being used...
 533  */
 534 OSStatus
 535 SecSMIMEFindBulkAlgForRecipients(SecCertificateRef *rcerts, SECOidTag *bulkalgtag, int *keysize)
 536 {
 537     unsigned long cipher;
 538     int mapi;
 539
 540     cipher = smime_choose_cipher(NULL, rcerts);
 541     mapi = smime_mapi_by_cipher(cipher);
 542     if (mapi < 0) {
 543         return SECFailure;
 544     }
 545
 546     *bulkalgtag = smime_cipher_map[mapi].algtag;
 547     *keysize = smime_keysize_by_cipher(smime_cipher_map[mapi].cipher);
 548
 549     return SECSuccess;
 550 }
 551
 552 /*
 553  * SecSMIMECreateSMIMECapabilities - get S/MIME capabilities for this instance of NSS
 554  *
 555  * scans the list of allowed and enabled ciphers and construct a PKCS9-compliant
 556  * S/MIME capabilities attribute value.
 557  *
 558  * XXX Please note that, in contradiction to RFC2633 2.5.2, the capabilities only include
 559  * symmetric ciphers, NO signature algorithms or key encipherment algorithms.
 560  *
 561  * "poolp" - arena pool to create the S/MIME capabilities data on
 562  * "dest" - CSSM_DATA to put the data in
 563  * "includeFortezzaCiphers" - PR_TRUE if fortezza ciphers should be included
 564  */
 565 OSStatus
 566 SecSMIMECreateSMIMECapabilities(SecArenaPoolRef pool, CSSM_DATA_PTR dest, Boolean includeFortezzaCiphers)
 567 {
 568     PLArenaPool *poolp = (PLArenaPool *)pool;
 569     NSSSMIMECapability *cap;
 570     NSSSMIMECapability **smime_capabilities;
 571     smime_cipher_map_entry *map;
 572     SECOidData *oiddata;
 573     CSSM_DATA_PTR dummy;
 574     int i, capIndex;
 575
 576     /* if we have an old NSSSMIMECapability array, we'll reuse it (has the right size) */
 577     /* smime_cipher_map_count + 1 is an upper bound - we might end up with less */
 578     smime_capabilities = (NSSSMIMECapability **)PORT_ZAlloc((smime_cipher_map_count + 1)
 579                                       * sizeof(NSSSMIMECapability *));
 580     if (smime_capabilities == NULL)
 581         return SECFailure;
 582
 583     capIndex = 0;
 584
 585     /* Add all the symmetric ciphers
 586      * We walk the cipher list backwards, as it is ordered by increasing strength,
 587      * we prefer the stronger cipher over a weaker one, and we have to list the
 588      * preferred algorithm first */
 589     for (i = smime_cipher_map_count - 1; i >= 0; i--) {
 590         /* Find the corresponding entry in the cipher map. */
 591         map = &(smime_cipher_map[i]);
 592         if (!map->enabled)
 593             continue;
 594
 595         /* If we're using a non-Fortezza cert, only advertise non-Fortezza
 596            capabilities. (We advertise all capabilities if we have a
 597            Fortezza cert.) */
 598         if ((!includeFortezzaCiphers) && (map->cipher == SMIME_FORTEZZA))
 599             continue;
 600
 601         /* get next SMIME capability */
 602         cap = (NSSSMIMECapability *)PORT_ZAlloc(sizeof(NSSSMIMECapability));
 603         if (cap == NULL)
 604             break;
 605         smime_capabilities[capIndex++] = cap;
 606
 607         oiddata = SECOID_FindOIDByTag(map->algtag);
 608         if (oiddata == NULL)
 609             break;
 610
 611         cap->capabilityID.Data = oiddata->oid.Data;
 612         cap->capabilityID.Length = oiddata->oid.Length;
 613         cap->parameters.Data = map->parms ? map->parms->Data : NULL;
 614         cap->parameters.Length = map->parms ? map->parms->Length : 0;
 615         cap->cipher = smime_cipher_map[i].cipher;
 616     }
 617
 618     /* XXX add signature algorithms */
 619     /* XXX add key encipherment algorithms */
 620
 621     smime_capabilities[capIndex] = NULL;        /* last one - now encode */
 622     dummy = SEC_ASN1EncodeItem(poolp, dest, &smime_capabilities, NSSSMIMECapabilitiesTemplate);
 623
 624     /* now that we have the proper encoded SMIMECapabilities (or not),
 625      * free the work data */
 626     for (i = 0; smime_capabilities[i] != NULL; i++)
 627         PORT_Free(smime_capabilities[i]);
 628     PORT_Free(smime_capabilities);
 629
 630     return (dummy == NULL) ? SECFailure : SECSuccess;
 631 }
 632
 633 /*
 634  * SecSMIMECreateSMIMEEncKeyPrefs - create S/MIME encryption key preferences attr value
 635  *
 636  * "poolp" - arena pool to create the attr value on
 637  * "dest" - CSSM_DATA to put the data in
 638  * "cert" - certificate that should be marked as preferred encryption key
 639  *          cert is expected to have been verified for EmailRecipient usage.
 640  */
 641 OSStatus
 642 SecSMIMECreateSMIMEEncKeyPrefs(SecArenaPoolRef pool, CSSM_DATA_PTR dest, SecCertificateRef cert)
 643 {
 644     PLArenaPool *poolp = (PLArenaPool *)pool;
 645     NSSSMIMEEncryptionKeyPreference ekp;
 646     CSSM_DATA_PTR dummy = NULL;
 647     PLArenaPool *tmppoolp = NULL;
 648
 649     if (cert == NULL)
 650         goto loser;
 651
 652     tmppoolp = PORT_NewArena(1024);
 653     if (tmppoolp == NULL)
 654         goto loser;
 655
 656     /* XXX hardcoded IssuerSN choice for now */
 657     ekp.selector = NSSSMIMEEncryptionKeyPref_IssuerSN;
 658     ekp.id.issuerAndSN = CERT_GetCertIssuerAndSN(tmppoolp, cert);
 659     if (ekp.id.issuerAndSN == NULL)
 660         goto loser;
 661
 662     dummy = SEC_ASN1EncodeItem(poolp, dest, &ekp, smime_encryptionkeypref_template);
 663
 664 loser:
 665     if (tmppoolp) PORT_FreeArena(tmppoolp, PR_FALSE);
 666
 667     return (dummy == NULL) ? SECFailure : SECSuccess;
 668 }
 669
 670 /*
 671  * SecSMIMECreateSMIMEEncKeyPrefs - create S/MIME encryption key preferences attr value using MS oid
 672  *
 673  * "poolp" - arena pool to create the attr value on
 674  * "dest" - CSSM_DATA to put the data in
 675  * "cert" - certificate that should be marked as preferred encryption key
 676  *          cert is expected to have been verified for EmailRecipient usage.
 677  */
 678 OSStatus
 679 SecSMIMECreateMSSMIMEEncKeyPrefs(SecArenaPoolRef pool, CSSM_DATA_PTR dest, SecCertificateRef cert)
 680 {
 681     PLArenaPool *poolp = (PLArenaPool *)pool;
 682     CSSM_DATA_PTR dummy = NULL;
 683     PLArenaPool *tmppoolp = NULL;
 684     SecCmsIssuerAndSN *isn;
 685
 686     if (cert == NULL)
 687         goto loser;
 688
 689     tmppoolp = PORT_NewArena(1024);
 690     if (tmppoolp == NULL)
 691         goto loser;
 692
 693     isn = CERT_GetCertIssuerAndSN(tmppoolp, cert);
 694     if (isn == NULL)
 695         goto loser;
 696
 697     dummy = SEC_ASN1EncodeItem(poolp, dest, isn, SEC_ASN1_GET(SecCmsIssuerAndSNTemplate));
 698
 699 loser:
 700     if (tmppoolp) PORT_FreeArena(tmppoolp, PR_FALSE);
 701
 702     return (dummy == NULL) ? SECFailure : SECSuccess;
 703 }
 704
 705 /*
 706  * SecSMIMEGetCertFromEncryptionKeyPreference -
 707  *                              find cert marked by EncryptionKeyPreference attribute
 708  *
 709  * "keychainOrArray" - handle for the cert database to look in
 710  * "DERekp" - DER-encoded value of S/MIME Encryption Key Preference attribute
 711  *
 712  * if certificate is supposed to be found among the message's included certificates,
 713  * they are assumed to have been imported already.
 714  */
 715 SecCertificateRef
 716 SecSMIMEGetCertFromEncryptionKeyPreference(SecKeychainRef keychainOrArray, CSSM_DATA_PTR *rawCerts, CSSM_DATA_PTR DERekp)
 717 {
 718     PLArenaPool *tmppoolp = NULL;
 719     SecCertificateRef cert = NULL;
 720     NSSSMIMEEncryptionKeyPreference ekp;
 721
 722     tmppoolp = PORT_NewArena(1024);
 723     if (tmppoolp == NULL)
 724         return NULL;
 725
 726     /* decode DERekp */
 727     if (SEC_ASN1DecodeItem(tmppoolp, &ekp, smime_encryptionkeypref_template, DERekp) != SECSuccess)
 728         goto loser;
 729
 730     /* find cert */
 731     switch (ekp.selector) {
 732     case NSSSMIMEEncryptionKeyPref_IssuerSN:
 733         cert = CERT_FindCertByIssuerAndSN(keychainOrArray, rawCerts, NULL, tmppoolp, ekp.id.issuerAndSN);
 734         break;
 735     case NSSSMIMEEncryptionKeyPref_RKeyID:
 736         cert = CERT_FindCertBySubjectKeyID(keychainOrArray, rawCerts, NULL, &ekp.id.recipientKeyID->subjectKeyIdentifier);
 737         break;
 738     case NSSSMIMEEncryptionKeyPref_SubjectKeyID:
 739         cert = CERT_FindCertBySubjectKeyID(keychainOrArray, rawCerts, NULL, ekp.id.subjectKeyID);
 740         break;
 741     default:
 742         PORT_Assert(0);
 743     }
 744 loser:
 745     if (tmppoolp) PORT_FreeArena(tmppoolp, PR_FALSE);
 746
 747     return cert;
 748 }
 749
 750 #if 0
 751 extern const char __nss_smime_rcsid[];
 752 extern const char __nss_smime_sccsid[];
 753 #endif
 754
 755 #if 0 /* -- unused */
 756 Boolean
 757 NSSSMIME_VersionCheck(const char *importedVersion)
 758 {
 759 #if 1
 760     return PR_TRUE;
 761 #else
 762     /*
 763      * This is the secret handshake algorithm.
 764      *
 765      * This release has a simple version compatibility
 766      * check algorithm.  This release is not backward
 767      * compatible with previous major releases.  It is
 768      * not compatible with future major, minor, or
 769      * patch releases.
 770      */
 771     volatile char c; /* force a reference that won't get optimized away */
 772
 773     c = __nss_smime_rcsid[0] + __nss_smime_sccsid[0];
 774
 775     return NSS_VersionCheck(importedVersion);
 776 #endif
 777 }
 778 #endif