source4/heimdal/lib/krb5/crypto-evp.c

   1 /*
   2  * Copyright (c) 1997 - 2008 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 "krb5_locl.h"
  35
  36 void
  37 _krb5_evp_schedule(krb5_context context,
  38                    struct _krb5_key_type *kt,
  39                    struct _krb5_key_data *kd)
  40 {
  41     struct _krb5_evp_schedule *key = kd->schedule->data;
  42     const EVP_CIPHER *c = (*kt->evp)();
  43
  44     EVP_CIPHER_CTX_init(&key->ectx);
  45     EVP_CIPHER_CTX_init(&key->dctx);
  46
  47     EVP_CipherInit_ex(&key->ectx, c, NULL, kd->key->keyvalue.data, NULL, 1);
  48     EVP_CipherInit_ex(&key->dctx, c, NULL, kd->key->keyvalue.data, NULL, 0);
  49 }
  50
  51 void
  52 _krb5_evp_cleanup(krb5_context context, struct _krb5_key_data *kd)
  53 {
  54     struct _krb5_evp_schedule *key = kd->schedule->data;
  55     EVP_CIPHER_CTX_cleanup(&key->ectx);
  56     EVP_CIPHER_CTX_cleanup(&key->dctx);
  57 }
  58
  59 krb5_error_code
  60 _krb5_evp_encrypt(krb5_context context,
  61                 struct _krb5_key_data *key,
  62                 void *data,
  63                 size_t len,
  64                 krb5_boolean encryptp,
  65                 int usage,
  66                 void *ivec)
  67 {
  68     struct _krb5_evp_schedule *ctx = key->schedule->data;
  69     EVP_CIPHER_CTX *c;
  70     c = encryptp ? &ctx->ectx : &ctx->dctx;
  71     if (ivec == NULL) {
  72         /* alloca ? */
  73         size_t len2 = EVP_CIPHER_CTX_iv_length(c);
  74         void *loiv = malloc(len2);
  75         if (loiv == NULL) {
  76             krb5_clear_error_message(context);
  77             return ENOMEM;
  78         }
  79         memset(loiv, 0, len2);
  80         EVP_CipherInit_ex(c, NULL, NULL, NULL, loiv, -1);
  81         free(loiv);
  82     } else
  83         EVP_CipherInit_ex(c, NULL, NULL, NULL, ivec, -1);
  84     EVP_Cipher(c, data, data, len);
  85     return 0;
  86 }
  87
  88 static const unsigned char zero_ivec[EVP_MAX_BLOCK_LENGTH] = { 0 };
  89
  90 krb5_error_code
  91 _krb5_evp_encrypt_cts(krb5_context context,
  92                       struct _krb5_key_data *key,
  93                       void *data,
  94                       size_t len,
  95                       krb5_boolean encryptp,
  96                       int usage,
  97                       void *ivec)
  98 {
  99     size_t i, blocksize;
 100     struct _krb5_evp_schedule *ctx = key->schedule->data;
 101     unsigned char tmp[EVP_MAX_BLOCK_LENGTH], ivec2[EVP_MAX_BLOCK_LENGTH];
 102     EVP_CIPHER_CTX *c;
 103     unsigned char *p;
 104
 105     c = encryptp ? &ctx->ectx : &ctx->dctx;
 106
 107     blocksize = EVP_CIPHER_CTX_block_size(c);
 108
 109     if (len < blocksize) {
 110         krb5_set_error_message(context, EINVAL,
 111                                "message block too short");
 112         return EINVAL;
 113     } else if (len == blocksize) {
 114         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 115         EVP_Cipher(c, data, data, len);
 116         return 0;
 117     }
 118
 119     if (ivec)
 120         EVP_CipherInit_ex(c, NULL, NULL, NULL, ivec, -1);
 121     else
 122         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 123
 124     if (encryptp) {
 125
 126         p = data;
 127         i = ((len - 1) / blocksize) * blocksize;
 128         EVP_Cipher(c, p, p, i);
 129         p += i - blocksize;
 130         len -= i;
 131         memcpy(ivec2, p, blocksize);
 132
 133         for (i = 0; i < len; i++)
 134             tmp[i] = p[i + blocksize] ^ ivec2[i];
 135         for (; i < blocksize; i++)
 136             tmp[i] = 0 ^ ivec2[i];
 137
 138         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 139         EVP_Cipher(c, p, tmp, blocksize);
 140
 141         memcpy(p + blocksize, ivec2, len);
 142         if (ivec)
 143             memcpy(ivec, p, blocksize);
 144     } else {
 145         unsigned char tmp2[EVP_MAX_BLOCK_LENGTH], tmp3[EVP_MAX_BLOCK_LENGTH];
 146
 147         p = data;
 148         if (len > blocksize * 2) {
 149             /* remove last two blocks and round up, decrypt this with cbc, then do cts dance */
 150             i = ((((len - blocksize * 2) + blocksize - 1) / blocksize) * blocksize);
 151             memcpy(ivec2, p + i - blocksize, blocksize);
 152             EVP_Cipher(c, p, p, i);
 153             p += i;
 154             len -= i + blocksize;
 155         } else {
 156             if (ivec)
 157                 memcpy(ivec2, ivec, blocksize);
 158             else
 159                 memcpy(ivec2, zero_ivec, blocksize);
 160             len -= blocksize;
 161         }
 162
 163         memcpy(tmp, p, blocksize);
 164         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 165         EVP_Cipher(c, tmp2, p, blocksize);
 166
 167         memcpy(tmp3, p + blocksize, len);
 168         memcpy(tmp3 + len, tmp2 + len, blocksize - len); /* xor 0 */
 169
 170         for (i = 0; i < len; i++)
 171             p[i + blocksize] = tmp2[i] ^ tmp3[i];
 172
 173         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 174         EVP_Cipher(c, p, tmp3, blocksize);
 175
 176         for (i = 0; i < blocksize; i++)
 177             p[i] ^= ivec2[i];
 178         if (ivec)
 179             memcpy(ivec, tmp, blocksize);
 180     }
 181     return 0;
 182 }