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      1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com)
      2  * All rights reserved.
      3  *
      4  * This package is an SSL implementation written
      5  * by Eric Young (eay (at) cryptsoft.com).
      6  * The implementation was written so as to conform with Netscapes SSL.
      7  *
      8  * This library is free for commercial and non-commercial use as long as
      9  * the following conditions are aheared to.  The following conditions
     10  * apply to all code found in this distribution, be it the RC4, RSA,
     11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
     12  * included with this distribution is covered by the same copyright terms
     13  * except that the holder is Tim Hudson (tjh (at) cryptsoft.com).
     14  *
     15  * Copyright remains Eric Young's, and as such any Copyright notices in
     16  * the code are not to be removed.
     17  * If this package is used in a product, Eric Young should be given attribution
     18  * as the author of the parts of the library used.
     19  * This can be in the form of a textual message at program startup or
     20  * in documentation (online or textual) provided with the package.
     21  *
     22  * Redistribution and use in source and binary forms, with or without
     23  * modification, are permitted provided that the following conditions
     24  * are met:
     25  * 1. Redistributions of source code must retain the copyright
     26  *    notice, this list of conditions and the following disclaimer.
     27  * 2. Redistributions in binary form must reproduce the above copyright
     28  *    notice, this list of conditions and the following disclaimer in the
     29  *    documentation and/or other materials provided with the distribution.
     30  * 3. All advertising materials mentioning features or use of this software
     31  *    must display the following acknowledgement:
     32  *    "This product includes cryptographic software written by
     33  *     Eric Young (eay (at) cryptsoft.com)"
     34  *    The word 'cryptographic' can be left out if the rouines from the library
     35  *    being used are not cryptographic related :-).
     36  * 4. If you include any Windows specific code (or a derivative thereof) from
     37  *    the apps directory (application code) you must include an acknowledgement:
     38  *    "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)"
     39  *
     40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
     41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     50  * SUCH DAMAGE.
     51  *
     52  * The licence and distribution terms for any publically available version or
     53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
     54  * copied and put under another distribution licence
     55  * [including the GNU Public Licence.] */
     56 
     57 #include <openssl/cipher.h>
     58 
     59 #include <assert.h>
     60 
     61 #include <openssl/digest.h>
     62 #include <openssl/mem.h>
     63 
     64 
     65 #define PKCS5_SALT_LEN 8
     66 
     67 int EVP_BytesToKey(const EVP_CIPHER *type, const EVP_MD *md,
     68                    const uint8_t *salt, const uint8_t *data, size_t data_len,
     69                    unsigned count, uint8_t *key, uint8_t *iv) {
     70   EVP_MD_CTX c;
     71   uint8_t md_buf[EVP_MAX_MD_SIZE];
     72   unsigned niv, nkey, addmd = 0;
     73   unsigned mds = 0, i;
     74   int rv = 0;
     75 
     76   nkey = type->key_len;
     77   niv = type->iv_len;
     78 
     79   assert(nkey <= EVP_MAX_KEY_LENGTH);
     80   assert(niv <= EVP_MAX_IV_LENGTH);
     81 
     82   if (data == NULL) {
     83     return nkey;
     84   }
     85 
     86   EVP_MD_CTX_init(&c);
     87   for (;;) {
     88     if (!EVP_DigestInit_ex(&c, md, NULL)) {
     89       return 0;
     90     }
     91     if (addmd++) {
     92       if (!EVP_DigestUpdate(&c, md_buf, mds)) {
     93         goto err;
     94       }
     95     }
     96     if (!EVP_DigestUpdate(&c, data, data_len)) {
     97       goto err;
     98     }
     99     if (salt != NULL) {
    100       if (!EVP_DigestUpdate(&c, salt, PKCS5_SALT_LEN)) {
    101         goto err;
    102       }
    103     }
    104     if (!EVP_DigestFinal_ex(&c, md_buf, &mds)) {
    105       goto err;
    106     }
    107 
    108     for (i = 1; i < count; i++) {
    109       if (!EVP_DigestInit_ex(&c, md, NULL) ||
    110           !EVP_DigestUpdate(&c, md_buf, mds) ||
    111           !EVP_DigestFinal_ex(&c, md_buf, &mds)) {
    112         goto err;
    113       }
    114     }
    115 
    116     i = 0;
    117     if (nkey) {
    118       for (;;) {
    119         if (nkey == 0 || i == mds) {
    120           break;
    121         }
    122         if (key != NULL) {
    123           *(key++) = md_buf[i];
    124         }
    125         nkey--;
    126         i++;
    127       }
    128     }
    129 
    130     if (niv && i != mds) {
    131       for (;;) {
    132         if (niv == 0 || i == mds) {
    133           break;
    134         }
    135         if (iv != NULL) {
    136           *(iv++) = md_buf[i];
    137         }
    138         niv--;
    139         i++;
    140       }
    141     }
    142     if (nkey == 0 && niv == 0) {
    143       break;
    144     }
    145   }
    146   rv = type->key_len;
    147 
    148 err:
    149   EVP_MD_CTX_cleanup(&c);
    150   OPENSSL_cleanse(md_buf, EVP_MAX_MD_SIZE);
    151   return rv;
    152 }
    153