OSX/libsecurity_transform/lib/CEncryptDecrypt.c

   1 /*
   2  * Copyright (c) 2012 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 #include <CoreFoundation/CoreFoundation.h>
  26 #include "corecrypto/ccsha1.h"
  27 #include "corecrypto/ccrsa_priv.h"
  28 #include "corecrypto/ccrng_system.h"
  29 #include "corecrypto/ccn.h"
  30 #include "stdio.h"
  31 #include "misc.h"
  32 #include "Utilities.h"
  33
  34 // corecrypto headers don't like C++ (on a deaper level then extern "C" {} can fix
  35 // so we need a C "shim" for all our corecrypto use.
  36
  37 CFDataRef oaep_padding_via_c(int desired_message_length, CFDataRef dataValue);
  38 CFDataRef oaep_padding_via_c(int desired_message_length, CFDataRef dataValue) CF_RETURNS_RETAINED
  39 {
  40         cc_unit paddingBuffer[ccn_nof_size(desired_message_length)];
  41         bzero(paddingBuffer, sizeof(cc_unit) * ccn_nof_size(desired_message_length)); // XXX needed??
  42         static dispatch_once_t randomNumberGenneratorInitialzed;
  43         static struct ccrng_system_state rng;
  44         dispatch_once(&randomNumberGenneratorInitialzed, ^{
  45         ccrng_system_init(&rng);
  46         });
  47
  48     ccrsa_oaep_encode(ccsha1_di(),
  49                       (struct ccrng_state*)&rng,
  50                       sizeof(paddingBuffer), (cc_unit*)paddingBuffer,
  51                       CFDataGetLength(dataValue), CFDataGetBytePtr(dataValue));
  52     ccn_swap(ccn_nof_size(sizeof(paddingBuffer)), (cc_unit*)paddingBuffer);
  53
  54     CFDataRef paddedValue = CFDataCreate(NULL, (UInt8*)paddingBuffer, desired_message_length);
  55         return paddedValue ? paddedValue : (void*)GetNoMemoryErrorAndRetain();
  56 }
  57
  58 CFDataRef oaep_unpadding_via_c(CFDataRef encodedMessage);
  59 CFDataRef oaep_unpadding_via_c(CFDataRef encodedMessage) CF_RETURNS_RETAINED
  60 {
  61         size_t mlen = CFDataGetLength(encodedMessage);
  62         cc_size n = ccn_nof_size(mlen);
  63         cc_unit paddingBuffer[n];
  64         UInt8 plainText[mlen];
  65
  66         ccn_read_uint(n, paddingBuffer, mlen, CFDataGetBytePtr(encodedMessage));
  67         size_t plainTextLength = mlen;
  68     int err = ccrsa_oaep_decode(ccsha1_di(), &plainTextLength, plainText, mlen, paddingBuffer);
  69
  70     if (err) {
  71                 // XXX should make a CFError or something.
  72         CFErrorRef error = fancy_error(CFSTR("CoreCrypto"), err, CFSTR("OAEP decode error"));
  73         CFRetainSafe(error);
  74         return (void*)error;
  75     }
  76         CFDataRef result = CFDataCreate(NULL, (UInt8*)plainText, plainTextLength);
  77         return result;
  78 }