src/external/heimdal/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             return krb5_enomem(context);
  77         memset(loiv, 0, len2);
  78         EVP_CipherInit_ex(c, NULL, NULL, NULL, loiv, -1);
  79         free(loiv);
  80     } else
  81         EVP_CipherInit_ex(c, NULL, NULL, NULL, ivec, -1);
  82     EVP_Cipher(c, data, data, len);
  83     return 0;
  84 }
  85
  86 static const unsigned char zero_ivec[EVP_MAX_BLOCK_LENGTH] = { 0 };
  87
  88 krb5_error_code
  89 _krb5_evp_encrypt_cts(krb5_context context,
  90                       struct _krb5_key_data *key,
  91                       void *data,
  92                       size_t len,
  93                       krb5_boolean encryptp,
  94                       int usage,
  95                       void *ivec)
  96 {
  97     size_t i, blocksize;
  98     struct _krb5_evp_schedule *ctx = key->schedule->data;
  99     unsigned char tmp[EVP_MAX_BLOCK_LENGTH], ivec2[EVP_MAX_BLOCK_LENGTH];
 100     EVP_CIPHER_CTX *c;
 101     unsigned char *p;
 102
 103     c = encryptp ? &ctx->ectx : &ctx->dctx;
 104
 105     blocksize = EVP_CIPHER_CTX_block_size(c);
 106
 107     if (len < blocksize) {
 108         krb5_set_error_message(context, EINVAL,
 109                                "message block too short");
 110         return EINVAL;
 111     } else if (len == blocksize) {
 112         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 113         EVP_Cipher(c, data, data, len);
 114         return 0;
 115     }
 116
 117     if (ivec)
 118         EVP_CipherInit_ex(c, NULL, NULL, NULL, ivec, -1);
 119     else
 120         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 121
 122     if (encryptp) {
 123
 124         p = data;
 125         i = ((len - 1) / blocksize) * blocksize;
 126         EVP_Cipher(c, p, p, i);
 127         p += i - blocksize;
 128         len -= i;
 129         memcpy(ivec2, p, blocksize);
 130
 131         for (i = 0; i < len; i++)
 132             tmp[i] = p[i + blocksize] ^ ivec2[i];
 133         for (; i < blocksize; i++)
 134             tmp[i] = 0 ^ ivec2[i];
 135
 136         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 137         EVP_Cipher(c, p, tmp, blocksize);
 138
 139         memcpy(p + blocksize, ivec2, len);
 140         if (ivec)
 141             memcpy(ivec, p, blocksize);
 142     } else {
 143         unsigned char tmp2[EVP_MAX_BLOCK_LENGTH], tmp3[EVP_MAX_BLOCK_LENGTH];
 144
 145         p = data;
 146         if (len > blocksize * 2) {
 147             /* remove last two blocks and round up, decrypt this with cbc, then do cts dance */
 148             i = ((((len - blocksize * 2) + blocksize - 1) / blocksize) * blocksize);
 149             memcpy(ivec2, p + i - blocksize, blocksize);
 150             EVP_Cipher(c, p, p, i);
 151             p += i;
 152             len -= i + blocksize;
 153         } else {
 154             if (ivec)
 155                 memcpy(ivec2, ivec, blocksize);
 156             else
 157                 memcpy(ivec2, zero_ivec, blocksize);
 158             len -= blocksize;
 159         }
 160
 161         memcpy(tmp, p, blocksize);
 162         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 163         EVP_Cipher(c, tmp2, p, blocksize);
 164
 165         memcpy(tmp3, p + blocksize, len);
 166         memcpy(tmp3 + len, tmp2 + len, blocksize - len); /* xor 0 */
 167
 168         for (i = 0; i < len; i++)
 169             p[i + blocksize] = tmp2[i] ^ tmp3[i];
 170
 171         EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
 172         EVP_Cipher(c, p, tmp3, blocksize);
 173
 174         for (i = 0; i < blocksize; i++)
 175             p[i] ^= ivec2[i];
 176         if (ivec)
 177             memcpy(ivec, tmp, blocksize);
 178     }
 179     return 0;
 180 }