ref: 2cdc6577ef8a251bf1740439cf5bfc47050dab41
dir: /third_party/boringssl/src/crypto/cipher_extra/derive_key.c/
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/cipher.h>
#include <assert.h>
#include <openssl/digest.h>
#include <openssl/mem.h>
#define PKCS5_SALT_LEN 8
int EVP_BytesToKey(const EVP_CIPHER *type, const EVP_MD *md,
const uint8_t *salt, const uint8_t *data, size_t data_len,
unsigned count, uint8_t *key, uint8_t *iv) {
EVP_MD_CTX c;
uint8_t md_buf[EVP_MAX_MD_SIZE];
unsigned niv, nkey, addmd = 0;
unsigned mds = 0, i;
int rv = 0;
nkey = type->key_len;
niv = type->iv_len;
assert(nkey <= EVP_MAX_KEY_LENGTH);
assert(niv <= EVP_MAX_IV_LENGTH);
if (data == NULL) {
return nkey;
}
EVP_MD_CTX_init(&c);
for (;;) {
if (!EVP_DigestInit_ex(&c, md, NULL)) {
goto err;
}
if (addmd++) {
if (!EVP_DigestUpdate(&c, md_buf, mds)) {
goto err;
}
}
if (!EVP_DigestUpdate(&c, data, data_len)) {
goto err;
}
if (salt != NULL) {
if (!EVP_DigestUpdate(&c, salt, PKCS5_SALT_LEN)) {
goto err;
}
}
if (!EVP_DigestFinal_ex(&c, md_buf, &mds)) {
goto err;
}
for (i = 1; i < count; i++) {
if (!EVP_DigestInit_ex(&c, md, NULL) ||
!EVP_DigestUpdate(&c, md_buf, mds) ||
!EVP_DigestFinal_ex(&c, md_buf, &mds)) {
goto err;
}
}
i = 0;
if (nkey) {
for (;;) {
if (nkey == 0 || i == mds) {
break;
}
if (key != NULL) {
*(key++) = md_buf[i];
}
nkey--;
i++;
}
}
if (niv && i != mds) {
for (;;) {
if (niv == 0 || i == mds) {
break;
}
if (iv != NULL) {
*(iv++) = md_buf[i];
}
niv--;
i++;
}
}
if (nkey == 0 && niv == 0) {
break;
}
}
rv = type->key_len;
err:
EVP_MD_CTX_cleanup(&c);
OPENSSL_cleanse(md_buf, EVP_MAX_MD_SIZE);
return rv;
}