AppleCSP/AES/aescsp.cpp

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 /*
  20  * aescsp.cpp - glue between BlockCryptor and AES implementation
  21  * Written by Doug Mitchell 10/3/2000
  22  */
  23
  24 #include "aescspi.h"
  25 #include "rijndaelApi.h"
  26 #include "rijndael-alg-ref.h"
  27 #include "cspdebugging.h"
  28
  29 #define DEFAULT_BLOCK_SIZE              (MIN_AES_BLOCK_BITS / 8)
  30
  31 #define DEBUG_ED                0               /* general encrypt/decrypt debug */
  32 #if             DEBUG_ED
  33 #define dprint(s)       printf s
  34 #else
  35 #define dprint(s)
  36 #endif
  37
  38 #define DEBUG_SIZES             0
  39 #if             DEBUG_SIZES
  40 #define logSize(s, final, encr, ibs, in, out) \
  41         printf("%s final %d encr %d inbufsz %d inSize %d outSize %d\n", \
  42         s, final, encr, ibs, in, out)
  43 #else
  44 #define logSize(s, final, encr, ibs, in, out)
  45 #endif
  46
  47 /*
  48  * AES symmetric key generation.
  49  * This algorithm has key size restrictions which don't fit with the
  50  * standard AppleSymmKeyGenContext model so we have to do some addditional
  51  * checking.
  52  */
  53 void AESKeyGenContext::generate(
  54         const Context   &context,
  55         CssmKey                 &symKey,
  56         CssmKey                 &dummyKey)
  57 {
  58         uint32 reqKeySize = context.getInt(
  59                 CSSM_ATTRIBUTE_KEY_LENGTH,
  60                 CSSMERR_CSP_MISSING_ATTR_KEY_LENGTH);
  61         switch(reqKeySize) {
  62                 case MIN_AES_KEY_BITS:
  63                 case MID_AES_KEY_BITS:
  64                 case MAX_AES_KEY_BITS:
  65                         break;
  66                 default:
  67                         CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEY_SIZE);
  68         }
  69         AppleSymmKeyGenContext::generateSymKey(
  70                 context,
  71                 session(),
  72                 symKey);
  73 }
  74
  75 /*
  76  * AES encrypt/decrypt.
  77  */
  78 AESContext::~AESContext()
  79 {
  80         deleteKey();
  81         memset(mRawKey, 0, MAX_AES_KEY_BITS / 8);
  82         mInitFlag = false;
  83 }
  84
  85 void AESContext::aesError(
  86         int artn,
  87         const char *errStr)
  88 {
  89         CSSM_RETURN crtn;
  90         errorLog2("AESContext: %s : %d\n", errStr, artn);
  91         switch(artn) {
  92                 case BAD_KEY_INSTANCE:
  93                 default:
  94                         crtn = CSSMERR_CSP_INTERNAL_ERROR;
  95                         break;
  96                 case BAD_KEY_MAT:
  97                         crtn = CSSMERR_CSP_INVALID_KEY;
  98                         break;
  99         }
 100         CssmError::throwMe(crtn);
 101 }
 102
 103 void AESContext::deleteKey()
 104 {
 105         if(mAesKey) {
 106                 memset(mAesKey, 0, sizeof(keyInstance));
 107                 session().free(mAesKey);
 108                 mAesKey = NULL;
 109         }
 110 }
 111
 112 /*
 113  * Standard CSPContext init, called from CSPFullPluginSession::init().
 114  * Reusable, e.g., query followed by en/decrypt. Even reusable after context
 115  * changed (i.e., new IV in Encrypted File System).
 116  */
 117 void AESContext::init(
 118         const Context &context,
 119         bool encrypting)
 120 {
 121         if(mInitFlag && !opStarted()) {
 122                 return;
 123         }
 124
 125         UInt32          keyLen;
 126         UInt8           *keyData = NULL;
 127         unsigned        lastBlockSize = mBlockSize;             // may be 0 (first time thru)
 128         bool            sameKeyAndBlockSizes = false;
 129
 130         /* obtain key from context */
 131         symmetricKeyBits(context, CSSM_ALGID_AES,
 132                 encrypting ? CSSM_KEYUSE_ENCRYPT : CSSM_KEYUSE_DECRYPT,
 133                 keyData, keyLen);
 134
 135         /*
 136          * Validate context
 137          * block size is optional
 138          */
 139         mBlockSize = context.getInt(CSSM_ATTRIBUTE_BLOCK_SIZE);
 140         if(mBlockSize == 0) {
 141                 mBlockSize = DEFAULT_BLOCK_SIZE;
 142         }
 143
 144
 145         /*
 146          * Delete existing key if key size or block size changed
 147          */
 148         if((lastBlockSize == mBlockSize) && (mRawKeySize == keyLen)) {
 149                 sameKeyAndBlockSizes = true;
 150         }
 151         if((mAesKey != NULL) && !sameKeyAndBlockSizes) {
 152                 deleteKey();
 153         }
 154
 155         int opt128 = 0;
 156         if((mBlockSize == (MIN_AES_BLOCK_BITS/8)) &&
 157            (keyLen == (MIN_AES_KEY_BITS/8)) &&
 158            doAES128) {
 159                 opt128 = 1;
 160         }
 161
 162         /* create new key if needed */
 163         if(mAesKey == NULL) {
 164                 mAesKey = (keyInstance *)session().malloc(sizeof(keyInstance));
 165         }
 166
 167         /* init key only if key size, block size, or key bits have changed */
 168         if(!sameKeyAndBlockSizes || memcmp(mRawKey, keyData, mRawKeySize)) {
 169                 int artn = makeKey((keyInstance *)mAesKey,
 170                         keyLen * 8,
 171                         mBlockSize * 8,
 172                         (word8 *)keyData,
 173                         opt128);
 174                 if(artn < 0) {
 175                         aesError(artn, "makeKey");
 176                 }
 177
 178                 /* save this raw key data */
 179                 memmove(mRawKey, keyData, mRawKeySize);
 180                 mRawKeySize = keyLen;
 181         }
 182
 183         if(opt128) {
 184                 /* optimized path */
 185                 mEncryptFcn = rijndaelBlockEncrypt128;
 186                 mDecryptFcn = rijndaelBlockDecrypt128;
 187         }
 188         else {
 189                 /* common standard path */
 190                 mEncryptFcn = rijndaelBlockEncrypt;
 191                 mDecryptFcn = rijndaelBlockDecrypt;
 192         }
 193
 194         /* Finally, have BlockCryptor do its setup */
 195         setup(mBlockSize, context);
 196         mInitFlag = true;
 197 }
 198
 199 /*
 200  * Functions called by BlockCryptor
 201  */
 202 void AESContext::encryptBlock(
 203         const void              *plainText,                     // length implied (one block)
 204         size_t                  plainTextLen,
 205         void                    *cipherText,
 206         size_t                  &cipherTextLen,         // in/out, throws on overflow
 207         bool                    final)                          // ignored
 208 {
 209         if(plainTextLen != mBlockSize) {
 210                 CssmError::throwMe(CSSMERR_CSP_INPUT_LENGTH_ERROR);
 211         }
 212         if(cipherTextLen < mBlockSize) {
 213                 CssmError::throwMe(CSSMERR_CSP_OUTPUT_LENGTH_ERROR);
 214         }
 215         int artn = mEncryptFcn(mAesKey,
 216                 (word8 *)plainText,
 217                 (word8 *)cipherText);
 218         if(artn < 0) {
 219                 aesError(artn, "rijndaelBlockEncrypt");
 220         }
 221         cipherTextLen = mBlockSize;
 222 }
 223
 224 void AESContext::decryptBlock(
 225         const void              *cipherText,            // length implied (one cipher block)
 226         void                    *plainText,
 227         size_t                  &plainTextLen,          // in/out, throws on overflow
 228         bool                    final)                          // ignored
 229 {
 230         if(plainTextLen < mBlockSize) {
 231                 CssmError::throwMe(CSSMERR_CSP_OUTPUT_LENGTH_ERROR);
 232         }
 233         int artn = mDecryptFcn(mAesKey,
 234                 (word8 *)cipherText,
 235                 (word8 *)plainText);
 236         if(artn < 0) {
 237                 aesError(artn, "rijndaelBlockDecrypt");
 238         }
 239         plainTextLen = mBlockSize;
 240 }
 241