/*
- * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2015-2019 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
*/
#include <string.h>
+#include <openssl/core_names.h>
#include <openssl/ec.h>
#include <openssl/evp.h>
-#include "ec_lcl.h"
+#include <openssl/kdf.h>
+#include "ec_local.h"
/* Key derivation function from X9.63/SECG */
-/* Way more than we will ever need */
-#define ECDH_KDF_MAX (1 << 30)
-
int ecdh_KDF_X9_63(unsigned char *out, size_t outlen,
const unsigned char *Z, size_t Zlen,
const unsigned char *sinfo, size_t sinfolen,
const EVP_MD *md)
{
- EVP_MD_CTX *mctx = NULL;
- int rv = 0;
- unsigned int i;
- size_t mdlen;
- unsigned char ctr[4];
- if (sinfolen > ECDH_KDF_MAX || outlen > ECDH_KDF_MAX
- || Zlen > ECDH_KDF_MAX)
- return 0;
- mctx = EVP_MD_CTX_new();
- if (mctx == NULL)
- return 0;
- mdlen = EVP_MD_size(md);
- for (i = 1;; i++) {
- unsigned char mtmp[EVP_MAX_MD_SIZE];
- if (!EVP_DigestInit_ex(mctx, md, NULL))
- goto err;
- ctr[3] = i & 0xFF;
- ctr[2] = (i >> 8) & 0xFF;
- ctr[1] = (i >> 16) & 0xFF;
- ctr[0] = (i >> 24) & 0xFF;
- if (!EVP_DigestUpdate(mctx, Z, Zlen))
- goto err;
- if (!EVP_DigestUpdate(mctx, ctr, sizeof(ctr)))
- goto err;
- if (!EVP_DigestUpdate(mctx, sinfo, sinfolen))
- goto err;
- if (outlen >= mdlen) {
- if (!EVP_DigestFinal(mctx, out, NULL))
- goto err;
- outlen -= mdlen;
- if (outlen == 0)
- break;
- out += mdlen;
- } else {
- if (!EVP_DigestFinal(mctx, mtmp, NULL))
- goto err;
- memcpy(out, mtmp, outlen);
- OPENSSL_cleanse(mtmp, mdlen);
- break;
- }
+ int ret = 0;
+ EVP_KDF_CTX *kctx = NULL;
+ OSSL_PARAM params[4], *p = params;
+ const char *mdname = EVP_MD_name(md);
+ EVP_KDF *kdf = EVP_KDF_fetch(NULL, OSSL_KDF_NAME_X963KDF, NULL);
+
+ if ((kctx = EVP_KDF_CTX_new(kdf)) != NULL) {
+ *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
+ (char *)mdname,
+ strlen(mdname) + 1);
+ *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
+ (void *)Z, Zlen);
+ *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
+ (void *)sinfo, sinfolen);
+ *p = OSSL_PARAM_construct_end();
+
+ ret = EVP_KDF_CTX_set_params(kctx, params) > 0
+ && EVP_KDF_derive(kctx, out, outlen) > 0;
+ EVP_KDF_CTX_free(kctx);
}
- rv = 1;
- err:
- EVP_MD_CTX_free(mctx);
- return rv;
+ EVP_KDF_free(kdf);
+ return ret;
}
/*-