108 lines
2.9 KiB
C
108 lines
2.9 KiB
C
/*
|
|
* Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining
|
|
* a copy of this software and associated documentation files (the
|
|
* "Software"), to deal in the Software without restriction, including
|
|
* without limitation the rights to use, copy, modify, merge, publish,
|
|
* distribute, sublicense, and/or sell copies of the Software, and to
|
|
* permit persons to whom the Software is furnished to do so, subject to
|
|
* the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be
|
|
* included in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
|
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
|
|
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
|
|
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
|
|
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
* SOFTWARE.
|
|
*/
|
|
|
|
#include "t_inner.h"
|
|
|
|
const unsigned char br_hkdf_no_salt = 0;
|
|
|
|
/* see bearssl_kdf.h */
|
|
void
|
|
br_hkdf_init(br_hkdf_context *hc, const br_hash_class *digest_vtable,
|
|
const void *salt, size_t salt_len)
|
|
{
|
|
br_hmac_key_context kc;
|
|
unsigned char tmp[64];
|
|
|
|
if (salt == BR_HKDF_NO_SALT) {
|
|
salt = tmp;
|
|
salt_len = br_digest_size(digest_vtable);
|
|
memset(tmp, 0, salt_len);
|
|
}
|
|
br_hmac_key_init(&kc, digest_vtable, salt, salt_len);
|
|
br_hmac_init(&hc->u.hmac_ctx, &kc, 0);
|
|
hc->dig_len = br_hmac_size(&hc->u.hmac_ctx);
|
|
}
|
|
|
|
/* see bearssl_kdf.h */
|
|
void
|
|
br_hkdf_inject(br_hkdf_context *hc, const void *ikm, size_t ikm_len)
|
|
{
|
|
br_hmac_update(&hc->u.hmac_ctx, ikm, ikm_len);
|
|
}
|
|
|
|
/* see bearssl_kdf.h */
|
|
void
|
|
br_hkdf_flip(br_hkdf_context *hc)
|
|
{
|
|
unsigned char tmp[64];
|
|
|
|
br_hmac_out(&hc->u.hmac_ctx, tmp);
|
|
br_hmac_key_init(&hc->u.prk_ctx,
|
|
br_hmac_get_digest(&hc->u.hmac_ctx), tmp, hc->dig_len);
|
|
hc->ptr = hc->dig_len;
|
|
hc->chunk_num = 0;
|
|
}
|
|
|
|
/* see bearssl_kdf.h */
|
|
size_t
|
|
br_hkdf_produce(br_hkdf_context *hc,
|
|
const void *info, size_t info_len, void *out, size_t out_len)
|
|
{
|
|
size_t tlen;
|
|
|
|
tlen = 0;
|
|
while (out_len > 0) {
|
|
size_t clen;
|
|
|
|
if (hc->ptr == hc->dig_len) {
|
|
br_hmac_context hmac_ctx;
|
|
unsigned char x;
|
|
|
|
hc->chunk_num ++;
|
|
if (hc->chunk_num == 256) {
|
|
return tlen;
|
|
}
|
|
x = hc->chunk_num;
|
|
br_hmac_init(&hmac_ctx, &hc->u.prk_ctx, 0);
|
|
if (x != 1) {
|
|
br_hmac_update(&hmac_ctx, hc->buf, hc->dig_len);
|
|
}
|
|
br_hmac_update(&hmac_ctx, info, info_len);
|
|
br_hmac_update(&hmac_ctx, &x, 1);
|
|
br_hmac_out(&hmac_ctx, hc->buf);
|
|
hc->ptr = 0;
|
|
}
|
|
clen = hc->dig_len - hc->ptr;
|
|
if (clen > out_len) {
|
|
clen = out_len;
|
|
}
|
|
memcpy(out, hc->buf + hc->ptr, clen);
|
|
out = (unsigned char *)out + clen;
|
|
out_len -= clen;
|
|
hc->ptr += clen;
|
|
tlen += clen;
|
|
}
|
|
return tlen;
|
|
}
|