103 lines
2.7 KiB
C
103 lines
2.7 KiB
C
|
/*
|
||
|
|
* CDDL HEADER START
|
||
|
|
*
|
||
|
|
* This file and its contents are supplied under the terms of the
|
||
|
|
* Common Development and Distribution License ("CDDL"), version 1.0.
|
||
|
|
* You may only use this file in accordance with the terms of version
|
||
|
|
* 1.0 of the CDDL.
|
||
|
|
*
|
||
|
|
* A full copy of the text of the CDDL should have accompanied this
|
||
|
|
* source. A copy of the CDDL is also available via the Internet at
|
||
|
|
* http://www.illumos.org/license/CDDL.
|
||
|
|
*
|
||
|
|
* CDDL HEADER END
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Copyright (c) 2017, Datto, Inc. All rights reserved.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <sys/dmu.h>
|
||
|
|
#include <sys/hkdf.h>
|
||
|
|
#include <sys/freebsd_crypto.h>
|
||
|
|
#include <sys/hkdf.h>
|
||
|
|
|
||
|
|
static int
|
||
|
|
hkdf_sha512_extract(uint8_t *salt, uint_t salt_len, uint8_t *key_material,
|
||
|
|
uint_t km_len, uint8_t *out_buf)
|
||
|
|
{
|
||
|
|
crypto_key_t key;
|
||
|
|
|
||
|
|
/* initialize the salt as a crypto key */
|
||
|
|
key.ck_format = CRYPTO_KEY_RAW;
|
||
|
|
key.ck_length = CRYPTO_BYTES2BITS(salt_len);
|
||
|
|
key.ck_data = salt;
|
||
|
|
|
||
|
|
crypto_mac(&key, key_material, km_len, out_buf, SHA512_DIGEST_LENGTH);
|
||
|
|
|
||
|
|
return (0);
|
||
|
|
}
|
||
|
|
|
||
|
|
static int
|
||
|
|
hkdf_sha512_expand(uint8_t *extract_key, uint8_t *info, uint_t info_len,
|
||
|
|
uint8_t *out_buf, uint_t out_len)
|
||
|
|
{
|
||
|
|
struct hmac_ctx ctx;
|
||
|
|
crypto_key_t key;
|
||
|
|
uint_t i, T_len = 0, pos = 0;
|
||
|
|
uint8_t c;
|
||
|
|
uint_t N = (out_len + SHA512_DIGEST_LENGTH) / SHA512_DIGEST_LENGTH;
|
||
|
|
uint8_t T[SHA512_DIGEST_LENGTH];
|
||
|
|
|
||
|
|
if (N > 255)
|
||
|
|
return (SET_ERROR(EINVAL));
|
||
|
|
|
||
|
|
/* initialize the salt as a crypto key */
|
||
|
|
key.ck_format = CRYPTO_KEY_RAW;
|
||
|
|
key.ck_length = CRYPTO_BYTES2BITS(SHA512_DIGEST_LENGTH);
|
||
|
|
key.ck_data = extract_key;
|
||
|
|
|
||
|
|
for (i = 1; i <= N; i++) {
|
||
|
|
c = i;
|
||
|
|
|
||
|
|
crypto_mac_init(&ctx, &key);
|
||
|
|
crypto_mac_update(&ctx, T, T_len);
|
||
|
|
crypto_mac_update(&ctx, info, info_len);
|
||
|
|
crypto_mac_update(&ctx, &c, 1);
|
||
|
|
crypto_mac_final(&ctx, T, SHA512_DIGEST_LENGTH);
|
||
|
|
bcopy(T, out_buf + pos,
|
||
|
|
(i != N) ? SHA512_DIGEST_LENGTH : (out_len - pos));
|
||
|
|
pos += SHA512_DIGEST_LENGTH;
|
||
|
|
}
|
||
|
|
|
||
|
|
return (0);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* HKDF is designed to be a relatively fast function for deriving keys from a
|
||
|
|
* master key + a salt. We use this function to generate new encryption keys
|
||
|
|
* so as to avoid hitting the cryptographic limits of the underlying
|
||
|
|
* encryption modes. Note that, for the sake of deriving encryption keys, the
|
||
|
|
* info parameter is called the "salt" everywhere else in the code.
|
||
|
|
*/
|
||
|
|
int
|
||
|
|
hkdf_sha512(uint8_t *key_material, uint_t km_len, uint8_t *salt,
|
||
|
|
uint_t salt_len, uint8_t *info, uint_t info_len, uint8_t *output_key,
|
||
|
|
uint_t out_len)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
uint8_t extract_key[SHA512_DIGEST_LENGTH];
|
||
|
|
|
||
|
|
ret = hkdf_sha512_extract(salt, salt_len, key_material, km_len,
|
||
|
|
extract_key);
|
||
|
|
if (ret != 0)
|
||
|
|
return (ret);
|
||
|
|
|
||
|
|
ret = hkdf_sha512_expand(extract_key, info, info_len, output_key,
|
||
|
|
out_len);
|
||
|
|
if (ret != 0)
|
||
|
|
return (ret);
|
||
|
|
|
||
|
|
return (0);
|
||
|
|
}
|