lib/hcrypto/evp-aes-cts.c

   1 /*
   2  * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35
  36 #define HC_DEPRECATED
  37
  38 #include <sys/types.h>
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <assert.h>
  43
  44
  45 #include <krb5-types.h>
  46
  47 #if defined(BUILD_KRB5_LIB) && defined(HAVE_OPENSSL)
  48 #include <openssl/evp.h>
  49 #include <openssl/aes.h>
  50
  51 #define _hc_EVP_hcrypto_aes_128_cts _krb5_EVP_hcrypto_aes_128_cts
  52 #define _hc_EVP_hcrypto_aes_192_cts _krb5_EVP_hcrypto_aes_192_cts
  53 #define _hc_EVP_hcrypto_aes_256_cts _krb5_EVP_hcrypto_aes_256_cts
  54
  55 const EVP_CIPHER * _krb5_EVP_hcrypto_aes_128_cts(void);
  56 const EVP_CIPHER * _krb5_EVP_hcrypto_aes_192_cts(void);
  57 const EVP_CIPHER * _krb5_EVP_hcrypto_aes_256_cts(void);
  58
  59 #else
  60 #include <evp.h>
  61 #include <aes.h>
  62
  63 #define _hc_EVP_hcrypto_aes_128_cts hc_EVP_hcrypto_aes_128_cts
  64 #define _hc_EVP_hcrypto_aes_192_cts hc_EVP_hcrypto_aes_192_cts
  65 #define _hc_EVP_hcrypto_aes_256_cts hc_EVP_hcrypto_aes_256_cts
  66
  67 #endif
  68
  69 /*
  70  *
  71  */
  72
  73 static int
  74 aes_cts_init(EVP_CIPHER_CTX *ctx,
  75              const unsigned char * key,
  76              const unsigned char * iv,
  77              int encp)
  78 {
  79     AES_KEY *k = ctx->cipher_data;
  80     if (ctx->encrypt)
  81         AES_set_encrypt_key(key, ctx->cipher->key_len * 8, k);
  82     else
  83         AES_set_decrypt_key(key, ctx->cipher->key_len * 8, k);
  84     return 1;
  85 }
  86
  87 static void
  88 _krb5_aes_cts_encrypt(const unsigned char *in, unsigned char *out,
  89                       size_t len, const AES_KEY *key,
  90                       unsigned char *ivec, const int encryptp)
  91 {
  92     unsigned char tmp[AES_BLOCK_SIZE];
  93     int i;
  94
  95     /*
  96      * In the framework of kerberos, the length can never be shorter
  97      * then at least one blocksize.
  98      */
  99
 100     if (encryptp) {
 101
 102         while(len > AES_BLOCK_SIZE) {
 103             for (i = 0; i < AES_BLOCK_SIZE; i++)
 104                 tmp[i] = in[i] ^ ivec[i];
 105             AES_encrypt(tmp, out, key);
 106             memcpy(ivec, out, AES_BLOCK_SIZE);
 107             len -= AES_BLOCK_SIZE;
 108             in += AES_BLOCK_SIZE;
 109             out += AES_BLOCK_SIZE;
 110         }
 111
 112         for (i = 0; i < len; i++)
 113             tmp[i] = in[i] ^ ivec[i];
 114         for (; i < AES_BLOCK_SIZE; i++)
 115             tmp[i] = 0 ^ ivec[i];
 116
 117         AES_encrypt(tmp, out - AES_BLOCK_SIZE, key);
 118
 119         memcpy(out, ivec, len);
 120         memcpy(ivec, out - AES_BLOCK_SIZE, AES_BLOCK_SIZE);
 121
 122     } else {
 123         unsigned char tmp2[AES_BLOCK_SIZE];
 124         unsigned char tmp3[AES_BLOCK_SIZE];
 125
 126         while(len > AES_BLOCK_SIZE * 2) {
 127             memcpy(tmp, in, AES_BLOCK_SIZE);
 128             AES_decrypt(in, out, key);
 129             for (i = 0; i < AES_BLOCK_SIZE; i++)
 130                 out[i] ^= ivec[i];
 131             memcpy(ivec, tmp, AES_BLOCK_SIZE);
 132             len -= AES_BLOCK_SIZE;
 133             in += AES_BLOCK_SIZE;
 134             out += AES_BLOCK_SIZE;
 135         }
 136
 137         len -= AES_BLOCK_SIZE;
 138
 139         memcpy(tmp, in, AES_BLOCK_SIZE); /* save last iv */
 140         AES_decrypt(in, tmp2, key);
 141
 142         memcpy(tmp3, in + AES_BLOCK_SIZE, len);
 143         memcpy(tmp3 + len, tmp2 + len, AES_BLOCK_SIZE - len); /* xor 0 */
 144
 145         for (i = 0; i < len; i++)
 146             out[i + AES_BLOCK_SIZE] = tmp2[i] ^ tmp3[i];
 147
 148         AES_decrypt(tmp3, out, key);
 149         for (i = 0; i < AES_BLOCK_SIZE; i++)
 150             out[i] ^= ivec[i];
 151         memcpy(ivec, tmp, AES_BLOCK_SIZE);
 152     }
 153 }
 154
 155 static int
 156 aes_cts_do_cipher(EVP_CIPHER_CTX *ctx,
 157                   unsigned char *out,
 158                   const unsigned char *in,
 159                   unsigned int len)
 160 {
 161     AES_KEY *k = ctx->cipher_data;
 162
 163     if (len < AES_BLOCK_SIZE)
 164         abort();  /* krb5_abortx(context, "invalid use of AES_CTS_encrypt"); */
 165     if (len == AES_BLOCK_SIZE) {
 166         if (ctx->encrypt)
 167             AES_encrypt(in, out, k);
 168         else
 169             AES_decrypt(in, out, k);
 170     } else {
 171         _krb5_aes_cts_encrypt(in, out, len, k, ctx->iv, ctx->encrypt);
 172     }
 173
 174     return 1;
 175 }
 176
 177
 178 static int
 179 aes_cts_cleanup(EVP_CIPHER_CTX *ctx)
 180 {
 181     memset(ctx->cipher_data, 0, sizeof(AES_KEY));
 182     return 1;
 183 }
 184
 185 /**
 186  * The AES-128 cts cipher type (hcrypto)
 187  *
 188  * @return the AES-128 EVP_CIPHER pointer.
 189  *
 190  * @ingroup hcrypto_evp
 191  */
 192
 193 const EVP_CIPHER *
 194 _hc_EVP_hcrypto_aes_128_cts(void)
 195 {
 196     static const EVP_CIPHER aes_128_cts = {
 197         0,
 198         1,
 199         16,
 200         16,
 201         EVP_CIPH_CBC_MODE,
 202         aes_cts_init,
 203         aes_cts_do_cipher,
 204         aes_cts_cleanup,
 205         sizeof(AES_KEY),
 206         NULL,
 207         NULL,
 208         NULL,
 209         NULL
 210     };
 211
 212     return &aes_128_cts;
 213 }
 214
 215 /**
 216  * The AES-192 cts cipher type (hcrypto)
 217  *
 218  * @return the AES-192 EVP_CIPHER pointer.
 219  *
 220  * @ingroup hcrypto_evp
 221  */
 222
 223 const EVP_CIPHER *
 224 _hc_EVP_hcrypto_aes_192_cts(void)
 225 {
 226     static const EVP_CIPHER aes_192_cts = {
 227         0,
 228         1,
 229         24,
 230         16,
 231         EVP_CIPH_CBC_MODE,
 232         aes_cts_init,
 233         aes_cts_do_cipher,
 234         aes_cts_cleanup,
 235         sizeof(AES_KEY),
 236         NULL,
 237         NULL,
 238         NULL,
 239         NULL
 240     };
 241
 242     return &aes_192_cts;
 243 }
 244
 245 /**
 246  * The AES-256 cts cipher type (hcrypto)
 247  *
 248  * @return the AES-256 EVP_CIPHER pointer.
 249  *
 250  * @ingroup hcrypto_evp
 251  */
 252
 253 const EVP_CIPHER *
 254 _hc_EVP_hcrypto_aes_256_cts(void)
 255 {
 256     static const EVP_CIPHER aes_256_cts = {
 257         0,
 258         1,
 259         32,
 260         16,
 261         EVP_CIPH_CBC_MODE,
 262         aes_cts_init,
 263         aes_cts_do_cipher,
 264         aes_cts_cleanup,
 265         sizeof(AES_KEY),
 266         NULL,
 267         NULL,
 268         NULL,
 269         NULL
 270     };
 271
 272     return &aes_256_cts;
 273 }