OSX/sec/SOSCircle/SecureObjectSync/SOSECWrapUnwrap.c

   1 //
   2 //  cc_CFData.c
   3 //  ProtectedCloudStorage
   4 //
   5 //  Copyright (c) 2014 Apple Inc. All rights reserved.
   6 //
   7
   8 #include "SOSInternal.h"
   9
  10 #include <AssertMacros.h>
  11
  12 #include <CommonCrypto/CommonRandomSPI.h>
  13 #include <utilities/SecCFWrappers.h>
  14 #include <utilities/SecCFError.h>
  15 #include <utilities/SecBuffer.h>
  16 #include <corecrypto/ccec.h>
  17
  18
  19 #if 0 && defined(CCEC_RFC6637_DEBUG_KEYS)
  20 #define DEBUGKEYS CCEC_RFC6637_DEBUG_KEYS
  21 #else
  22 #define DEBUGKEYS 0
  23 #endif
  24
  25 const char fingerprint[20] = "fingerprint";
  26
  27 const uint8_t kAlgorithmID = 1;
  28
  29 CFMutableDataRef
  30 SOSCopyECWrappedData(ccec_pub_ctx *ec_ctx, CFDataRef data, CFErrorRef *error)
  31 {
  32     CFMutableDataRef result = NULL;
  33     CFMutableDataRef output = NULL;
  34     size_t outputLength;
  35     int res;
  36
  37     require_quiet(SecRequirementError(data != NULL, error, CFSTR("data required for wrapping")), exit);
  38     require_quiet(SecRequirementError(ec_ctx != NULL, error, CFSTR("ec pub key required for wrapping")), exit);
  39
  40     outputLength = ccec_rfc6637_wrap_key_size(ec_ctx, CCEC_RFC6637_COMPACT_KEYS | DEBUGKEYS, CFDataGetLength(data));
  41
  42     output = CFDataCreateMutableWithScratch(NULL, outputLength);
  43     require_quiet(SecAllocationError(output, error, CFSTR("%s CFData allocation failed"), __FUNCTION__), exit);
  44
  45     res = ccec_rfc6637_wrap_key(ec_ctx, CFDataGetMutableBytePtr(output), CCEC_RFC6637_COMPACT_KEYS | DEBUGKEYS, kAlgorithmID,
  46                                 CFDataGetLength(data), CFDataGetBytePtr(data), &ccec_rfc6637_dh_curve_p256,
  47                                 &ccec_rfc6637_wrap_sha256_kek_aes128, (const uint8_t *)fingerprint,
  48                                 ccDevRandomGetRngState());
  49     require_noerr_action(res, exit, SOSErrorCreate(kSOSErrorProcessingFailure, error, NULL, CFSTR("Wrap failed with %d"), res));
  50
  51     CFTransferRetained(result, output);
  52
  53 exit:
  54     CFReleaseNull(output);
  55     return result;
  56 }
  57
  58 bool SOSPerformWithUnwrappedData(ccec_full_ctx_t ec_ctx, CFDataRef data, CFErrorRef *error,
  59                                  void (^operation)(size_t size, uint8_t *buffer))
  60 {
  61     __block bool result = false;
  62
  63     PerformWithBufferAndClear(CFDataGetLength(data), ^(size_t size, uint8_t *buffer) {
  64         size_t outputLength = size;
  65         int ec_result;
  66         uint8_t alg;
  67         ec_result = ccec_rfc6637_unwrap_key(ec_ctx, &outputLength, buffer,
  68                                             CCEC_RFC6637_COMPACT_KEYS | DEBUGKEYS, &alg, &ccec_rfc6637_dh_curve_p256,
  69                                             &ccec_rfc6637_unwrap_sha256_kek_aes128, (const uint8_t *)fingerprint,
  70                                             CFDataGetLength(data), CFDataGetBytePtr(data));
  71
  72         require_noerr_action(ec_result, exit, SOSErrorCreate(kSOSErrorProcessingFailure, error, NULL, CFSTR("ccec_rfc6637_unwrap_key failed with %d"), ec_result));
  73         require_quiet(SecRequirementError(alg == kAlgorithmID, error, CFSTR("Unexpected algorithm: %d"), (int)alg), exit);
  74
  75         operation(outputLength, buffer);
  76
  77         result = true;
  78     exit:
  79         ;
  80     });
  81
  82     return result;
  83 }
  84
  85 CFMutableDataRef
  86 SOSCopyECUnwrappedData(ccec_full_ctx_t ec_ctx, CFDataRef data, CFErrorRef *error)
  87 {
  88     uint8_t alg;
  89     CFMutableDataRef result = NULL;
  90     CFMutableDataRef output = NULL;
  91     size_t outputLength = CFDataGetLength(data);
  92     int res;
  93
  94     output = CFDataCreateMutableWithScratch(NULL, outputLength);
  95     require_quiet(SecAllocationError(output, error, CFSTR("%s CFData allocation failed"), __FUNCTION__), exit);
  96
  97     res = ccec_rfc6637_unwrap_key(ec_ctx, &outputLength, CFDataGetMutableBytePtr(output),
  98                                   CCEC_RFC6637_COMPACT_KEYS | DEBUGKEYS, &alg, &ccec_rfc6637_dh_curve_p256,
  99                                   &ccec_rfc6637_unwrap_sha256_kek_aes128, (const uint8_t *)fingerprint,
 100                                   CFDataGetLength(data), CFDataGetBytePtr(data));
 101     require_noerr_action(res, exit, SOSErrorCreate(kSOSErrorProcessingFailure, error, NULL, CFSTR("Unwrap failed with %d"), res));
 102     require_quiet(SecRequirementError(alg == kAlgorithmID, error, CFSTR("Unexpected algorithm: %d"), (int)alg), exit);
 103
 104     CFDataSetLength(output, outputLength);
 105
 106     CFTransferRetained(result, output);
 107
 108 exit:
 109     CFReleaseNull(output);
 110     return result;
 111 }