OSX/sec/Security/SecECKey.c

   1 /*
   2  * Copyright (c) 2010-2015 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * SecECKey.c - CoreFoundation based rsa key object
  26  */
  27
  28 #include "SecECKey.h"
  29 #include "SecECKeyPriv.h"
  30
  31 #include <Security/SecKeyInternal.h>
  32 #include <Security/SecItem.h>
  33 #include <Security/SecBasePriv.h>
  34 #include <AssertMacros.h>
  35 #include <Security/SecureTransport.h> /* For error codes. */
  36 #include <CoreFoundation/CFData.h> /* For error codes. */
  37 #include <fcntl.h>
  38 #include <sys/types.h>
  39 #include <unistd.h>
  40 #include <CoreFoundation/CFNumber.h>
  41 #include <Security/SecFramework.h>
  42 #include <Security/SecRandom.h>
  43 #include <utilities/debugging.h>
  44 #include "SecItemPriv.h"
  45 #include <Security/SecInternal.h>
  46 #include <utilities/SecCFError.h>
  47 #include <utilities/SecCFWrappers.h>
  48 #include <utilities/array_size.h>
  49 #include <corecrypto/ccec.h>
  50 #include <corecrypto/ccsha1.h>
  51 #include <corecrypto/ccsha2.h>
  52 #include <corecrypto/ccrng.h>
  53 #include <corecrypto/ccder_decode_eckey.h>
  54
  55 #define kMaximumECKeySize 521
  56
  57 static CFIndex SecECKeyGetAlgorithmID(SecKeyRef key) {
  58     return kSecECDSAAlgorithmID;
  59 }
  60
  61
  62 /*
  63  *
  64  * Public Key
  65  *
  66  */
  67
  68 /* Public key static functions. */
  69 static void SecECPublicKeyDestroy(SecKeyRef key) {
  70     /* Zero out the public key */
  71     ccec_pub_ctx_t pubkey;
  72     pubkey.pub = key->key;
  73     if (ccec_ctx_cp(pubkey).zp)
  74         cc_clear(ccec_pub_ctx_size(ccn_sizeof_n(ccec_ctx_n(pubkey))), pubkey.pub);
  75 }
  76
  77 static ccec_const_cp_t getCPForPublicSize(CFIndex encoded_length)
  78 {
  79     size_t keysize = ccec_x963_import_pub_size(encoded_length);
  80     if(ccec_keysize_is_supported(keysize)) {
  81         return ccec_get_cp(keysize);
  82     }
  83     ccec_const_cp_t nullCP = { .zp = NULL };
  84     return nullCP;
  85 }
  86
  87 static ccec_const_cp_t getCPForPrivateSize(CFIndex encoded_length)
  88 {
  89     size_t keysize = ccec_x963_import_priv_size(encoded_length);
  90     if(ccec_keysize_is_supported(keysize)) {
  91         return ccec_get_cp(keysize);
  92     }
  93     ccec_const_cp_t nullCP = { .zp = NULL };
  94     return nullCP;
  95 }
  96
  97 static ccoid_t ccoid_secp192r1 = CC_EC_OID_SECP192R1;
  98 static ccoid_t ccoid_secp256r1 = CC_EC_OID_SECP256R1;
  99 static ccoid_t ccoid_secp224r1 = CC_EC_OID_SECP224R1;
 100 static ccoid_t ccoid_secp384r1 = CC_EC_OID_SECP384R1;
 101 static ccoid_t ccoid_secp521r1 = CC_EC_OID_SECP521R1;
 102
 103 static ccec_const_cp_t ccec_cp_for_oid(const unsigned char *oid)
 104 {
 105     if (oid!=NULL) {
 106         if (ccoid_equal(oid, ccoid_secp192r1)) {
 107             return ccec_cp_192();
 108         } else if (ccoid_equal(oid, ccoid_secp256r1)) {
 109             return ccec_cp_256();
 110         } else if (ccoid_equal(oid, ccoid_secp224r1)) {
 111             return ccec_cp_224();
 112         } else if (ccoid_equal(oid, ccoid_secp384r1)) {
 113             return ccec_cp_384();
 114         } else if (ccoid_equal(oid, ccoid_secp521r1)) {
 115             return ccec_cp_521();
 116         }
 117     }
 118     return (ccec_const_cp_t){NULL};
 119 }
 120
 121 static OSStatus SecECPublicKeyInit(SecKeyRef key,
 122     const uint8_t *keyData, CFIndex keyDataLength, SecKeyEncoding encoding) {
 123     ccec_pub_ctx_t pubkey;
 124     pubkey.pub = key->key;
 125     OSStatus err = errSecParam;
 126
 127     switch (encoding) {
 128     case kSecDERKeyEncoding:
 129     {
 130         const SecDERKey *derKey = (const SecDERKey *)keyData;
 131         if (keyDataLength != sizeof(SecDERKey)) {
 132             err = errSecDecode;
 133             break;
 134         }
 135
 136         ccec_const_cp_t cp = getCPForPublicSize(derKey->keyLength);
 137         require_action_quiet(cp.zp, errOut, err = errSecDecode);
 138
 139         /* TODO: Parse and use real params from passed in derKey->algId.params */
 140         err = (ccec_import_pub(cp, derKey->keyLength, derKey->key, pubkey)
 141                ? errSecDecode : errSecSuccess);
 142         break;
 143     }
 144     case kSecKeyEncodingBytes:
 145     {
 146         ccec_const_cp_t cp = getCPForPublicSize(keyDataLength);
 147         require_action_quiet(cp.zp, errOut, err = errSecDecode);
 148         err = (ccec_import_pub(cp, keyDataLength, keyData, pubkey)
 149                ? errSecDecode : errSecSuccess);
 150         break;
 151     }
 152     case kSecExtractPublicFromPrivate:
 153     {
 154         ccec_full_ctx_t fullKey;
 155         fullKey._full = (ccec_full_ctx *) keyData;
 156
 157         cc_size fullKeyN = ccec_ctx_n(fullKey);
 158         require_quiet(fullKeyN <= ccn_nof(kMaximumECKeySize), errOut);
 159         memcpy(pubkey._pub, fullKey.pub, ccec_pub_ctx_size(ccn_sizeof_n(fullKeyN)));
 160         err = errSecSuccess;
 161         break;
 162     }
 163     case kSecKeyEncodingApplePkcs1:
 164     default:
 165         err = errSecParam;
 166         break;
 167     }
 168
 169 errOut:
 170     return err;
 171 }
 172
 173 static CFTypeRef SecECPublicKeyCopyOperationResult(SecKeyRef key, SecKeyOperationType operation, SecKeyAlgorithm algorithm,
 174                                                    CFArrayRef algorithms, SecKeyOperationMode mode,
 175                                                    CFTypeRef in1, CFTypeRef in2, CFErrorRef *error) {
 176     if (operation != kSecKeyOperationTypeVerify) {
 177         // EC public key supports only signature verification.
 178         return kCFNull;
 179     }
 180
 181     if (CFEqual(algorithm, kSecKeyAlgorithmECDSASignatureRFC4754) || CFEqual(algorithm, kSecKeyAlgorithmECDSASignatureDigestX962)) {
 182         if (mode == kSecKeyOperationModePerform) {
 183             bool valid = false;
 184             int err = -1;
 185             size_t sigLen = CFDataGetLength(in2);
 186             uint8_t *sig = (uint8_t *)CFDataGetBytePtr(in2);
 187             ccec_pub_ctx_t pubkey = { .pub = key->key };
 188
 189             if (CFEqual(algorithm, kSecKeyAlgorithmECDSASignatureDigestX962)) {
 190                 err = ccec_verify(pubkey, CFDataGetLength(in1), CFDataGetBytePtr(in1), sigLen, sig, &valid);
 191             } else {
 192                 if (ccec_signature_r_s_size(pubkey.fullt) * 2 != sigLen) {
 193                     SecError(errSecParam, error, CFSTR("bad signature size, got %d, expecting %d bytes"),
 194                              (int)sigLen, (int)ccec_signature_r_s_size(pubkey.fullt) * 2);
 195                     return NULL;
 196                 }
 197                 err = ccec_verify_composite(pubkey, CFDataGetLength(in1), CFDataGetBytePtr(in1),
 198                                             sig, sig + (sigLen >> 1), &valid);
 199             }
 200
 201             if (err != 0) {
 202                 SecError(errSecVerifyFailed, error, CFSTR("EC signature verification failed (ccerr %d)"), err);
 203                 return NULL;
 204             } else if (!valid) {
 205                 SecError(errSecVerifyFailed, error, CFSTR("EC signature verification failed, no match"));
 206                 return NULL;
 207             } else {
 208                 return kCFBooleanTrue;
 209             }
 210         } else {
 211             // Algorithm is supported.
 212             return kCFBooleanTrue;
 213         }
 214     } else {
 215         // Other algorithms are unsupported.
 216         return kCFNull;
 217     }
 218 }
 219
 220 static size_t SecECPublicKeyBlockSize(SecKeyRef key) {
 221     /* Get key size in octets */
 222     ccec_pub_ctx_t pubkey;
 223     pubkey.pub = key->key;
 224     return ccec_ctx_size(pubkey);
 225 }
 226
 227 /* Encode the public key and return it in a newly allocated CFDataRef. */
 228 static CFDataRef SecECPublicKeyExport(CFAllocatorRef allocator,
 229         ccec_pub_ctx_t pubkey) {
 230     size_t pub_size = ccec_export_pub_size(pubkey);
 231         CFMutableDataRef blob = CFDataCreateMutableWithScratch(allocator, pub_size);
 232     ccec_export_pub(pubkey, CFDataGetMutableBytePtr(blob));
 233         return blob;
 234 }
 235
 236 static CFDataRef SecECPublicKeyCopyExternalRepresentation(SecKeyRef key, CFErrorRef *error) {
 237     ccec_pub_ctx_t pubkey;
 238     pubkey.pub = key->key;
 239     return SecECPublicKeyExport(NULL, pubkey);
 240 }
 241
 242 static OSStatus SecECPublicKeyCopyPublicOctets(SecKeyRef key, CFDataRef *serailziation)
 243 {
 244     ccec_pub_ctx_t pubkey;
 245     pubkey.pub = key->key;
 246
 247         CFAllocatorRef allocator = CFGetAllocator(key);
 248     *serailziation = SecECPublicKeyExport(allocator, pubkey);
 249
 250     if (NULL == *serailziation)
 251         return errSecDecode;
 252     else
 253         return errSecSuccess;
 254 }
 255
 256 static CFDictionaryRef SecECPublicKeyCopyAttributeDictionary(SecKeyRef key) {
 257     CFDictionaryRef dict = SecKeyGeneratePublicAttributeDictionary(key, kSecAttrKeyTypeEC);
 258     CFMutableDictionaryRef mutableDict = CFDictionaryCreateMutableCopy(NULL, 0, dict);
 259     CFDictionarySetValue(mutableDict, kSecAttrCanDerive, kCFBooleanFalse);
 260     CFAssignRetained(dict, mutableDict);
 261     return dict;
 262 }
 263
 264 static const char *
 265 getCurveName(SecKeyRef key)
 266 {
 267     SecECNamedCurve curveType = SecECKeyGetNamedCurve(key);
 268
 269     switch (curveType)
 270     {
 271         case kSecECCurveSecp256r1:
 272             return "kSecECCurveSecp256r1";
 273             break;
 274         case kSecECCurveSecp384r1:
 275             return "kSecECCurveSecp384r1";
 276             break;
 277         case kSecECCurveSecp521r1:
 278             return "kSecECCurveSecp521r1";
 279         default:
 280             return "kSecECCurveNone";
 281     }
 282 }
 283
 284 static CFStringRef SecECPublicKeyCopyKeyDescription(SecKeyRef key)
 285 {
 286     CFStringRef keyDescription = NULL;
 287     CFMutableStringRef strings[2] = { NULL, };
 288     const char* curve = getCurveName(key);
 289
 290     ccec_pub_ctx_t ecPubkey = { .pub = key->key };
 291     size_t len = ccec_ctx_size(ecPubkey);
 292     uint8_t buffer[len];
 293     for (int i = 0; i < 2; ++i) {
 294         ccn_write_uint(ccec_ctx_n(ecPubkey), (i == 0) ? ccec_ctx_x(ecPubkey) : ccec_ctx_y(ecPubkey), len, buffer);
 295         require_quiet(strings[i] = CFStringCreateMutable(kCFAllocatorDefault, len * 2), fail);
 296         for (size_t byteIndex = 0; byteIndex < len; ++byteIndex) {
 297             CFStringAppendFormat(strings[i], NULL, CFSTR("%02X"), buffer[byteIndex]);
 298         }
 299     }
 300
 301     keyDescription = CFStringCreateWithFormat(kCFAllocatorDefault, NULL,
 302                                               CFSTR( "<SecKeyRef curve type: %s, algorithm id: %lu, key type: %s, version: %d, block size: %zu bits, y: %@, x: %@, addr: %p>"),
 303                                               curve, (long)SecKeyGetAlgorithmId(key), key->key_class->name, key->key_class->version,
 304                                               8 * SecKeyGetBlockSize(key), strings[1], strings[0], key);
 305
 306 fail:
 307         CFReleaseSafe(strings[0]);
 308         CFReleaseSafe(strings[1]);
 309         if(!keyDescription)
 310                 keyDescription = CFStringCreateWithFormat(kCFAllocatorDefault, NULL,
 311                                                   CFSTR("<SecKeyRef curve type: %s, algorithm id: %lu, key type: %s, version: %d, block size: %zu bits, addr: %p>"),
 312                                                   curve,(long)SecKeyGetAlgorithmId(key), key->key_class->name, key->key_class->version,
 313                                                   8 * SecKeyGetBlockSize(key), key);
 314
 315         return keyDescription;
 316 }
 317
 318 static const struct ccec_rfc6637_curve * get_rfc6637_curve(SecKeyRef key)
 319 {
 320     SecECNamedCurve curveType = SecECKeyGetNamedCurve(key);
 321
 322     if (curveType == kSecECCurveSecp256r1) {
 323         return &ccec_rfc6637_dh_curve_p256;
 324     } else if (curveType == kSecECCurveSecp521r1) {
 325         return &ccec_rfc6637_dh_curve_p521;
 326     }
 327     return NULL;
 328 }
 329
 330 static CFDataRef SecECKeyCopyWrapKey(SecKeyRef key, SecKeyWrapType type, CFDataRef unwrappedKey, CFDictionaryRef parameters, CFDictionaryRef *outParam, CFErrorRef *error)
 331 {
 332     ccec_pub_ctx_t pubkey;
 333     int err = errSecUnimplemented;
 334     const struct ccec_rfc6637_curve *curve;
 335     const struct ccec_rfc6637_wrap *wrap = NULL;
 336     uint8_t sym_alg = 0;
 337     int32_t flags = 0;
 338
 339     pubkey.pub = key->key;
 340
 341     if (type != kSecKeyWrapPublicKeyPGP) {
 342         SecError(errSecUnsupportedOperation, error, CFSTR("unsupported key wrapping algorithm"));
 343         return NULL;
 344     }
 345
 346     curve = get_rfc6637_curve(key);
 347     if (curve == NULL) {
 348         SecError(errSecUnsupportedOperation, error, CFSTR("unsupported curve"));
 349         return NULL;
 350     }
 351
 352     CFNumberRef num = CFDictionaryGetValue(parameters, _kSecKeyWrapPGPSymAlg);
 353     if (!isNumber(num) || !CFNumberGetValue(num, kCFNumberSInt8Type, &sym_alg)) {
 354         SecError(errSecUnsupportedOperation, error, CFSTR("unknown symalg given"));
 355         return NULL;
 356     }
 357
 358     CFDataRef fingerprint = CFDictionaryGetValue(parameters, _kSecKeyWrapPGPFingerprint);
 359     if (!isData(fingerprint) || CFDataGetLength(fingerprint) < kSecKeyWrapPGPFingerprintMinSize) {
 360         SecError(errSecUnsupportedOperation, error, CFSTR("invalid fingerprint"));
 361         return NULL;
 362     }
 363
 364     CFTypeRef wrapAlg = CFDictionaryGetValue(parameters, _kSecKeyWrapPGPWrapAlg);
 365     if (wrapAlg == NULL) {
 366         SecError(errSecUnsupportedOperation, error, CFSTR("no wrap alg"));
 367         return NULL;
 368     } else if (CFEqual(wrapAlg, _kSecKeyWrapRFC6637WrapDigestSHA256KekAES128)) {
 369         wrap = &ccec_rfc6637_wrap_sha256_kek_aes128;
 370     } else if (CFEqual(wrapAlg, _kSecKeyWrapRFC6637WrapDigestSHA512KekAES256)) {
 371         wrap = &ccec_rfc6637_wrap_sha512_kek_aes256;
 372     } else {
 373         SecError(errSecUnsupportedOperation, error, CFSTR("unknown wrap alg"));
 374         return NULL;
 375     }
 376
 377     num = CFDictionaryGetValue(parameters, _kSecKeyWrapRFC6637Flags);
 378     if (isNumber(num)) {
 379         if (!CFNumberGetValue(num, kCFNumberSInt32Type, &flags)) {
 380             SecError(errSecUnsupportedOperation, error, CFSTR("invalid flags: %@"), num);
 381             return NULL;
 382         }
 383     } else if (num) {
 384         SecError(errSecUnsupportedOperation, error, CFSTR("unknown flags"));
 385         return NULL;
 386     }
 387
 388     CFIndex unwrappedKey_size = CFDataGetLength(unwrappedKey);
 389
 390     CFIndex output_size = ccec_rfc6637_wrap_key_size(pubkey, flags, unwrappedKey_size);
 391     if (output_size == 0) {
 392         SecError(errSecUnsupportedOperation, error, CFSTR("can't wrap that key, can't build size"));
 393         return NULL;
 394     }
 395
 396     CFMutableDataRef data = CFDataCreateMutableWithScratch(NULL, output_size);
 397     require_quiet(data, errOut);
 398
 399     err = ccec_rfc6637_wrap_key(pubkey, CFDataGetMutableBytePtr(data), flags,
 400                                 sym_alg, CFDataGetLength(unwrappedKey), CFDataGetBytePtr(unwrappedKey),
 401                                 curve, wrap, CFDataGetBytePtr(fingerprint),
 402                                 ccrng_seckey);
 403     if (err) {
 404         SecError(errSecUnsupportedOperation, error, CFSTR("Failed to wrap key"));
 405         CFReleaseNull(data);
 406     }
 407
 408 errOut:
 409     return data;
 410 }
 411
 412 SecKeyDescriptor kSecECPublicKeyDescriptor = {
 413     .version = kSecKeyDescriptorVersion,
 414     .name = "ECPublicKey",
 415     .extraBytes = ccec_pub_ctx_size(ccn_sizeof(kMaximumECKeySize)),
 416     .init = SecECPublicKeyInit,
 417     .destroy = SecECPublicKeyDestroy,
 418     .blockSize = SecECPublicKeyBlockSize,
 419     .copyDictionary = SecECPublicKeyCopyAttributeDictionary,
 420     .copyExternalRepresentation = SecECPublicKeyCopyExternalRepresentation,
 421     .describe = SecECPublicKeyCopyKeyDescription,
 422     .getAlgorithmID = SecECKeyGetAlgorithmID,
 423     .copyPublic = SecECPublicKeyCopyPublicOctets,
 424     .copyWrapKey = SecECKeyCopyWrapKey,
 425     .copyOperationResult = SecECPublicKeyCopyOperationResult,
 426 };
 427
 428 /* Public Key API functions. */
 429 SecKeyRef SecKeyCreateECPublicKey(CFAllocatorRef allocator,
 430     const uint8_t *keyData, CFIndex keyDataLength,
 431     SecKeyEncoding encoding) {
 432     return SecKeyCreate(allocator, &kSecECPublicKeyDescriptor, keyData,
 433                         keyDataLength, encoding);
 434 }
 435
 436
 437
 438 /*
 439  *
 440  * Private Key
 441  *
 442  */
 443
 444 /* Private key static functions. */
 445 static void SecECPrivateKeyDestroy(SecKeyRef key) {
 446     /* Zero out the public key */
 447     ccec_full_ctx_t fullkey;
 448     fullkey.hdr = key->key;
 449     if (ccec_ctx_cp(fullkey).zp)
 450         cc_clear(ccec_full_ctx_size(ccn_sizeof_n(ccec_ctx_n(fullkey))), fullkey.hdr);
 451 }
 452
 453
 454 static OSStatus SecECPrivateKeyInit(SecKeyRef key,
 455     const uint8_t *keyData, CFIndex keyDataLength, SecKeyEncoding encoding) {
 456     ccec_full_ctx_t fullkey;
 457     fullkey.hdr = key->key;
 458     OSStatus err = errSecParam;
 459
 460     switch (encoding) {
 461     case kSecKeyEncodingPkcs1:
 462     {
 463         /* TODO: DER import size (and thus cp), pub.x, pub.y and k. */
 464         //err = ecc_import(keyData, keyDataLength, fullkey);
 465
 466         /* DER != PKCS#1, but we'll go along with it */
 467         const unsigned char *oid;
 468         size_t n;
 469         ccec_const_cp_t cp;
 470
 471         require_noerr_quiet(ccec_der_import_priv_keytype(keyDataLength, keyData, (ccoid_t*)&oid, &n), abort);
 472         cp = ccec_cp_for_oid(oid);
 473         if (cp.zp == NULL) {
 474             cp = ccec_curve_for_length_lookup(n * 8 /* bytes -> bits */,
 475                 ccec_cp_192(), ccec_cp_224(), ccec_cp_256(), ccec_cp_384(), ccec_cp_521(), NULL);
 476         }
 477         require_action_quiet(cp.zp != NULL, abort, err = errSecDecode);
 478         ccec_ctx_init(cp, fullkey);
 479
 480         require_noerr_quiet(ccec_der_import_priv(cp, keyDataLength, keyData, fullkey), abort);
 481         err = errSecSuccess;
 482         break;
 483     }
 484     case kSecKeyEncodingBytes:
 485     {
 486         ccec_const_cp_t cp = getCPForPrivateSize(keyDataLength);
 487         require_quiet(cp.zp != NULL, abort);
 488
 489         ccec_ctx_init(cp, fullkey);
 490         size_t pubSize = ccec_export_pub_size(fullkey);
 491
 492         require_quiet(pubSize < (size_t) keyDataLength, abort);
 493         require_noerr_action_quiet(ccec_import_pub(cp, pubSize, keyData, fullkey),
 494                                    abort,
 495                                    err = errSecDecode);
 496
 497
 498         keyData += pubSize;
 499         keyDataLength -= pubSize;
 500
 501         cc_unit *k = ccec_ctx_k(fullkey);
 502         require_noerr_action_quiet(ccn_read_uint(ccec_ctx_n(fullkey), k, keyDataLength, keyData),
 503                                    abort,
 504                                    err = errSecDecode);
 505
 506         err = errSecSuccess;
 507         break;
 508
 509     }
 510     case kSecGenerateKey:
 511     {
 512         CFDictionaryRef parameters = (CFDictionaryRef) keyData;
 513
 514         CFTypeRef ksize = CFDictionaryGetValue(parameters, kSecAttrKeySizeInBits);
 515         CFIndex keyLengthInBits = getIntValue(ksize);
 516
 517         ccec_const_cp_t cp = ccec_get_cp(keyLengthInBits);
 518
 519         if (!cp.zp) {
 520             secwarning("Invalid or missing key size in: %@", parameters);
 521             return errSecKeySizeNotAllowed;
 522         }
 523
 524         if (!ccec_generate_key_fips(cp, ccrng_seckey, fullkey))
 525             err = errSecSuccess;
 526         break;
 527     }
 528
 529     default:
 530         break;
 531     }
 532 abort:
 533     return err;
 534 }
 535
 536 static CFTypeRef SecECPrivateKeyCopyOperationResult(SecKeyRef key, SecKeyOperationType operation, SecKeyAlgorithm algorithm,
 537                                                     CFArrayRef allAlgorithms, SecKeyOperationMode mode,
 538                                                     CFTypeRef in1, CFTypeRef in2, CFErrorRef *error) {
 539     // Default answer is 'unsupported', unless we find out that we can support it.
 540     CFTypeRef result = kCFNull;
 541
 542     ccec_full_ctx_t fullkey = { .hdr = key->key };
 543     switch (operation) {
 544         case kSecKeyOperationTypeSign: {
 545             if (CFEqual(algorithm, kSecKeyAlgorithmECDSASignatureRFC4754)) {
 546                 if (mode == kSecKeyOperationModePerform) {
 547                     // Perform r/s mode of signature.
 548                     cc_size r_s_size = ccec_signature_r_s_size(fullkey);
 549                     result = CFDataCreateMutableWithScratch(NULL, r_s_size << 1);
 550                     uint8_t *signatureBuffer = CFDataGetMutableBytePtr((CFMutableDataRef)result);
 551                     int err = ccec_sign_composite(fullkey, CFDataGetLength(in1), CFDataGetBytePtr(in1),
 552                                                   signatureBuffer, signatureBuffer + r_s_size, ccrng_seckey);
 553                     require_action_quiet(err == 0, out, (CFReleaseNull(result),
 554                                                          SecError(errSecParam, error, CFSTR("%@: RFC4754 signing failed (ccerr %d)"),
 555                                                                   key, err)));
 556                 } else {
 557                     // Operation is supported.
 558                     result = kCFBooleanTrue;
 559                 }
 560             } else if (CFEqual(algorithm, kSecKeyAlgorithmECDSASignatureDigestX962)) {
 561                 if (mode == kSecKeyOperationModePerform) {
 562                     // Perform x962 mode of signature.
 563                     size_t size = ccec_sign_max_size(ccec_ctx_cp(fullkey));
 564                     result = CFDataCreateMutableWithScratch(NULL, size);
 565                     int err = ccec_sign(fullkey, CFDataGetLength(in1), CFDataGetBytePtr(in1),
 566                                         &size, CFDataGetMutableBytePtr((CFMutableDataRef)result), ccrng_seckey);
 567                     require_action_quiet(err == 0, out, (CFReleaseNull(result),
 568                                                          SecError(errSecParam, error, CFSTR("%@: X962 signing failed (ccerr %d)"),
 569                                                                   key, err)));
 570                     CFDataSetLength((CFMutableDataRef)result, size);
 571                 } else {
 572                     // Operation is supported.
 573                     result = kCFBooleanTrue;
 574                 }
 575             }
 576             break;
 577         }
 578         case kSecKeyOperationTypeKeyExchange:
 579             if (CFEqual(algorithm, kSecKeyAlgorithmECDHKeyExchangeStandard) ||
 580                 CFEqual(algorithm, kSecKeyAlgorithmECDHKeyExchangeCofactor)) {
 581                 if (mode == kSecKeyOperationModePerform) {
 582                     int err;
 583                     ccec_const_cp_t cp = getCPForPublicSize(CFDataGetLength(in1));
 584                     require_action_quiet(cp.zp != NULL, out,
 585                                          SecError(errSecParam, error, CFSTR("ECpriv sharedsecret: bad public key")));
 586                     uint8_t pubkeyBuffer[ccec_pub_ctx_size(ccn_sizeof(kMaximumECKeySize))];
 587                     ccec_pub_ctx_t pubkey = { .pub = (struct ccec_ctx_public *)pubkeyBuffer };
 588                     err = ccec_import_pub(cp, CFDataGetLength(in1), CFDataGetBytePtr(in1), pubkey);
 589                     require_noerr_action_quiet(err, out, SecError(errSecParam, error,
 590                                                                   CFSTR("ECpriv sharedsecret: bad public key (err %d)"), err));
 591                     size_t size = ccec_ccn_size(cp);
 592                     result = CFDataCreateMutableWithScratch(NULL, size);
 593                     err = ccecdh_compute_shared_secret(fullkey, pubkey, &size,
 594                                                        CFDataGetMutableBytePtr((CFMutableDataRef)result), ccrng_seckey);
 595                     require_noerr_action_quiet(err, out, (CFReleaseNull(result),
 596                                                           SecError(errSecDecode, error,
 597                                                                    CFSTR("ECpriv failed to compute shared secret (err %d)"), err)));
 598                     CFDataSetLength((CFMutableDataRef)result, size);
 599                 } else {
 600                     // Operation is supported.
 601                     result = kCFBooleanTrue;
 602                 }
 603             }
 604             break;
 605         default:
 606             break;
 607     }
 608
 609 out:
 610     return result;
 611 }
 612
 613 static size_t SecECPrivateKeyBlockSize(SecKeyRef key) {
 614     ccec_full_ctx_t fullkey;
 615     fullkey.hdr = key->key;
 616     /* Get key size in octets */
 617     return ccec_ctx_size(fullkey);
 618 }
 619
 620 static OSStatus SecECPrivateKeyCopyPublicOctets(SecKeyRef key, CFDataRef *serailziation)
 621 {
 622     ccec_full_ctx_t fullkey;
 623     fullkey.hdr = key->key;
 624
 625         CFAllocatorRef allocator = CFGetAllocator(key);
 626     *serailziation = SecECPublicKeyExport(allocator, fullkey);
 627
 628     if (NULL == *serailziation)
 629         return errSecDecode;
 630     else
 631         return errSecSuccess;
 632 }
 633
 634 static CFDataRef SecECPrivateKeyCopyExternalRepresentation(SecKeyRef key, CFErrorRef *error) {
 635     ccec_full_ctx_t fullkey;
 636     fullkey.hdr = key->key;
 637     size_t prime_size = ccec_cp_prime_size(ccec_ctx_cp(fullkey));
 638     size_t key_size = ccec_export_pub_size(fullkey) + prime_size;
 639     CFMutableDataRef blob = CFDataCreateMutableWithScratch(NULL, key_size);
 640     ccec_export_pub(fullkey, CFDataGetMutableBytePtr(blob));
 641     UInt8 *dest = CFDataGetMutableBytePtr(blob) + ccec_export_pub_size(fullkey);
 642     const cc_unit *k = ccec_ctx_k(fullkey);
 643     ccn_write_uint_padded(ccec_ctx_n(fullkey), k, prime_size, dest);
 644     return blob;
 645 }
 646
 647 static CFDictionaryRef SecECPrivateKeyCopyAttributeDictionary(SecKeyRef key) {
 648     /* Export the full ec key pair. */
 649     ccec_full_ctx_t fullkey;
 650     fullkey.hdr = key->key;
 651     CFDataRef fullKeyBlob = SecECPrivateKeyCopyExternalRepresentation(key, NULL);
 652
 653     CFDictionaryRef dict = SecKeyGeneratePrivateAttributeDictionary(key, kSecAttrKeyTypeEC, fullKeyBlob);
 654         CFReleaseSafe(fullKeyBlob);
 655         return dict;
 656 }
 657 static CFStringRef SecECPrivateKeyCopyKeyDescription(SecKeyRef key) {
 658
 659     const char* curve = getCurveName(key);
 660
 661         return CFStringCreateWithFormat(kCFAllocatorDefault,NULL,CFSTR( "<SecKeyRef curve type: %s, algorithm id: %lu, key type: %s, version: %d, block size: %zu bits, addr: %p>"), curve, (long)SecKeyGetAlgorithmId(key), key->key_class->name, key->key_class->version, (8*SecKeyGetBlockSize(key)), key);
 662
 663 }
 664
 665 static CFDataRef SecECKeyCopyUnwrapKey(SecKeyRef key, SecKeyWrapType type, CFDataRef wrappedKey, CFDictionaryRef parameters, CFDictionaryRef *outParam, CFErrorRef *error)
 666 {
 667     const struct ccec_rfc6637_curve *curve;
 668     const struct ccec_rfc6637_unwrap *unwrap;
 669     ccec_full_ctx_t fullkey;
 670     CFMutableDataRef data;
 671     int res;
 672     uint8_t sym_alg = 0;
 673     int32_t flags = 0;
 674
 675     fullkey.hdr = key->key;
 676
 677     curve = get_rfc6637_curve(key);
 678     if (curve == NULL) {
 679         SecError(errSecUnsupportedOperation, error, CFSTR("unsupported curve"));
 680         return NULL;
 681     }
 682
 683     CFTypeRef wrapAlg = CFDictionaryGetValue(parameters, _kSecKeyWrapPGPWrapAlg);
 684     if (wrapAlg == NULL) {
 685         SecError(errSecUnsupportedOperation, error, CFSTR("no wrap alg"));
 686         return NULL;
 687     } else if (CFEqual(wrapAlg, _kSecKeyWrapRFC6637WrapDigestSHA256KekAES128)) {
 688         unwrap = &ccec_rfc6637_unwrap_sha256_kek_aes128;
 689     } else if (CFEqual(wrapAlg, _kSecKeyWrapRFC6637WrapDigestSHA512KekAES256)) {
 690         unwrap = &ccec_rfc6637_unwrap_sha512_kek_aes256;
 691     } else {
 692         SecError(errSecUnsupportedOperation, error, CFSTR("unknown wrap alg"));
 693         return NULL;
 694     }
 695
 696     CFDataRef fingerprint = CFDictionaryGetValue(parameters, _kSecKeyWrapPGPFingerprint);
 697     if (!isData(fingerprint) || CFDataGetLength(fingerprint) < kSecKeyWrapPGPFingerprintMinSize) {
 698         SecError(errSecUnsupportedOperation, error, CFSTR("invalid fingerprint"));
 699         return NULL;
 700     }
 701
 702     CFNumberRef num = CFDictionaryGetValue(parameters, _kSecKeyWrapRFC6637Flags);
 703     if (isNumber(num)) {
 704         if (!CFNumberGetValue(num, kCFNumberSInt32Type, &flags)) {
 705             SecError(errSecUnsupportedOperation, error, CFSTR("invalid flags: %@"), num);
 706             return NULL;
 707         }
 708     } else if (num) {
 709         SecError(errSecUnsupportedOperation, error, CFSTR("unknown flags"));
 710         return NULL;
 711     }
 712
 713     size_t keysize = CFDataGetLength(wrappedKey);
 714     data = CFDataCreateMutableWithScratch(NULL, keysize);
 715     if (data == NULL)
 716         return NULL;
 717
 718     res = ccec_rfc6637_unwrap_key(fullkey, &keysize, CFDataGetMutableBytePtr(data),
 719                                   flags, &sym_alg, curve, unwrap,
 720                                   CFDataGetBytePtr(fingerprint),
 721                                   CFDataGetLength(wrappedKey), CFDataGetBytePtr(wrappedKey));
 722     if (res != 0) {
 723         CFReleaseNull(data);
 724         SecError(errSecUnsupportedOperation, error, CFSTR("failed to wrap key"));
 725         return NULL;
 726     }
 727     assert(keysize <= (size_t)CFDataGetLength(data));
 728     CFDataSetLength(data, keysize);
 729
 730     if (outParam) {
 731         CFMutableDictionaryRef out =  CFDictionaryCreateMutableForCFTypes(NULL);
 732         if (out) {
 733             CFNumberRef num = CFNumberCreate(NULL, kCFNumberSInt8Type, &sym_alg);
 734             if (num) {
 735                 CFDictionarySetValue(out, _kSecKeyWrapPGPSymAlg, num);
 736                 CFRelease(num);
 737             }
 738             *outParam = out;
 739         }
 740     }
 741
 742     return data;
 743 }
 744
 745 SecKeyDescriptor kSecECPrivateKeyDescriptor = {
 746     .version = kSecKeyDescriptorVersion,
 747     .name = "ECPrivateKey",
 748     .extraBytes = ccec_full_ctx_size(ccn_sizeof(kMaximumECKeySize)),
 749
 750     .init = SecECPrivateKeyInit,
 751     .destroy = SecECPrivateKeyDestroy,
 752     .blockSize = SecECPrivateKeyBlockSize,
 753     .copyDictionary = SecECPrivateKeyCopyAttributeDictionary,
 754     .describe = SecECPrivateKeyCopyKeyDescription,
 755     .getAlgorithmID = SecECKeyGetAlgorithmID,
 756     .copyPublic = SecECPrivateKeyCopyPublicOctets,
 757     .copyExternalRepresentation = SecECPrivateKeyCopyExternalRepresentation,
 758     .copyWrapKey = SecECKeyCopyWrapKey,
 759     .copyUnwrapKey = SecECKeyCopyUnwrapKey,
 760     .copyOperationResult = SecECPrivateKeyCopyOperationResult,
 761 };
 762
 763 /* Private Key API functions. */
 764 SecKeyRef SecKeyCreateECPrivateKey(CFAllocatorRef allocator,
 765     const uint8_t *keyData, CFIndex keyDataLength,
 766     SecKeyEncoding encoding) {
 767     return SecKeyCreate(allocator, &kSecECPrivateKeyDescriptor, keyData,
 768         keyDataLength, encoding);
 769 }
 770
 771
 772 OSStatus SecECKeyGeneratePair(CFDictionaryRef parameters,
 773                               SecKeyRef *publicKey, SecKeyRef *privateKey) {
 774     OSStatus status = errSecParam;
 775
 776     CFAllocatorRef allocator = NULL; /* @@@ get from parameters. */
 777     SecKeyRef pubKey = NULL;
 778
 779     SecKeyRef privKey = SecKeyCreate(allocator, &kSecECPrivateKeyDescriptor,
 780                                      (const void*) parameters, 0, kSecGenerateKey);
 781
 782     require(privKey, errOut);
 783
 784     /* Create SecKeyRef's from the pkcs1 encoded keys. */
 785     pubKey = SecKeyCreate(allocator, &kSecECPublicKeyDescriptor,
 786                           privKey->key, 0, kSecExtractPublicFromPrivate);
 787
 788     require(pubKey, errOut);
 789
 790     if (publicKey) {
 791         *publicKey = pubKey;
 792         pubKey = NULL;
 793     }
 794     if (privateKey) {
 795         *privateKey = privKey;
 796         privKey = NULL;
 797     }
 798
 799     status = errSecSuccess;
 800
 801 errOut:
 802     CFReleaseSafe(pubKey);
 803     CFReleaseSafe(privKey);
 804
 805     return status;
 806 }
 807
 808
 809 /* It's debatable whether this belongs here or in the ssl code since the
 810    curve values come from a tls related rfc4492. */
 811 SecECNamedCurve SecECKeyGetNamedCurve(SecKeyRef key) {
 812     SecECNamedCurve result = kSecECCurveNone;
 813     CFDictionaryRef attributes = NULL;
 814     require_quiet(SecKeyGetAlgorithmId(key) == kSecECDSAAlgorithmID, out);
 815     require_quiet(attributes = SecKeyCopyAttributes(key), out);
 816     CFTypeRef bitsRef = CFDictionaryGetValue(attributes, kSecAttrKeySizeInBits);
 817     CFIndex bits = 0;
 818     require_quiet(bitsRef != NULL && CFGetTypeID(bitsRef) == CFNumberGetTypeID() &&
 819                   CFNumberGetValue(bitsRef, kCFNumberCFIndexType, &bits), out);
 820     switch (bits) {
 821 #if 0
 822         case 192:
 823             result = kSecECCurveSecp192r1;
 824             break;
 825         case 224:
 826             result = kSecECCurveSecp224r1;
 827             break;
 828 #endif
 829         case 256:
 830             result = kSecECCurveSecp256r1;
 831             break;
 832         case 384:
 833             result = kSecECCurveSecp384r1;
 834             break;
 835         case 521:
 836             result = kSecECCurveSecp521r1;
 837             break;
 838     }
 839
 840 out:
 841     CFReleaseSafe(attributes);
 842     return result;
 843 }
 844
 845 CFDataRef SecECKeyCopyPublicBits(SecKeyRef key) {
 846     CFDataRef bytes = NULL;
 847     SecKeyCopyPublicBytes(key, &bytes);
 848     return bytes;
 849 }
 850
 851 /* Vile accessors that get us the pub or priv key to use temporarily */
 852
 853 bool SecECDoWithFullKey(SecKeyRef key, CFErrorRef* error, void (^action)(ccec_full_ctx_t private)) {
 854     if (key->key_class == &kSecECPrivateKeyDescriptor) {
 855         action(key->key);
 856     } else {
 857         return SecError(errSecParam, error, CFSTR("Not an EC Full Key object, sorry can't do."));
 858     }
 859
 860     return true;
 861 }
 862
 863 bool SecECDoWithPubKey(SecKeyRef key, CFErrorRef* error, void (^action)(ccec_pub_ctx_t public)) {
 864     if (key->key_class == &kSecECPublicKeyDescriptor) {
 865         action(key->key);
 866     } else {
 867         return SecError(errSecParam, error, CFSTR("Not an EC Public Key object, sorry can't do."));
 868     }
 869
 870     return true;
 871 }
 872