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