crmf_pbm.c
/*-
* Copyright 2007-2021 The OpenSSL Project Authors. All Rights Reserved.
* Copyright Nokia 2007-2019
* Copyright Siemens AG 2015-2019
*
* 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
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*
* CRMF implementation by Martin Peylo, Miikka Viljanen, and David von Oheimb.
*/
#include <string.h>
#include <openssl/rand.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
/* explicit #includes not strictly needed since implied by the above: */
#include <openssl/asn1t.h>
#include <openssl/crmf.h>
#include <openssl/err.h>
#include <openssl/params.h>
#include <openssl/core_names.h>
#include "internal/sizes.h"
#include "crmf_local.h"
/*-
* creates and initializes OSSL_CRMF_PBMPARAMETER (section 4.4)
* |slen| SHOULD be at least 8 (16 is common)
* |owfnid| e.g., NID_sha256
* |itercnt| MUST be >= 100 (e.g., 500) and <= OSSL_CRMF_PBM_MAX_ITERATION_COUNT
* |macnid| e.g., NID_hmac_sha1
* returns pointer to OSSL_CRMF_PBMPARAMETER on success, NULL on error
*/
OSSL_CRMF_PBMPARAMETER *OSSL_CRMF_pbmp_new(OSSL_LIB_CTX *libctx, size_t slen,
int owfnid, size_t itercnt,
int macnid)
{
OSSL_CRMF_PBMPARAMETER *pbm = NULL;
unsigned char *salt = NULL;
if ((pbm = OSSL_CRMF_PBMPARAMETER_new()) == NULL)
goto err;
/*
* salt contains a randomly generated value used in computing the key
* of the MAC process. The salt SHOULD be at least 8 octets (64
* bits) long.
*/
if ((salt = OPENSSL_malloc(slen)) == NULL)
goto err;
if (RAND_bytes_ex(libctx, salt, slen, 0) <= 0) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_FAILURE_OBTAINING_RANDOM);
goto err;
}
if (!ASN1_OCTET_STRING_set(pbm->salt, salt, (int)slen))
goto err;
/*
* owf identifies the hash algorithm and associated parameters used to
* compute the key used in the MAC process. All implementations MUST
* support SHA-1.
*/
if (!X509_ALGOR_set0(pbm->owf, OBJ_nid2obj(owfnid), V_ASN1_UNDEF, NULL)) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_SETTING_OWF_ALGOR_FAILURE);
goto err;
}
/*
* iterationCount identifies the number of times the hash is applied
* during the key computation process. The iterationCount MUST be a
* minimum of 100. Many people suggest using values as high as 1000
* iterations as the minimum value. The trade off here is between
* protection of the password from attacks and the time spent by the
* server processing all of the different iterations in deriving
* passwords. Hashing is generally considered a cheap operation but
* this may not be true with all hash functions in the future.
*/
if (itercnt < 100) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_ITERATIONCOUNT_BELOW_100);
goto err;
}
if (itercnt > OSSL_CRMF_PBM_MAX_ITERATION_COUNT) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_BAD_PBM_ITERATIONCOUNT);
goto err;
}
if (!ASN1_INTEGER_set(pbm->iterationCount, itercnt)) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_CRMFERROR);
goto err;
}
/*
* mac identifies the algorithm and associated parameters of the MAC
* function to be used. All implementations MUST support HMAC-SHA1 [HMAC].
* All implementations SHOULD support DES-MAC and Triple-DES-MAC [PKCS11].
*/
if (!X509_ALGOR_set0(pbm->mac, OBJ_nid2obj(macnid), V_ASN1_UNDEF, NULL)) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_SETTING_MAC_ALGOR_FAILURE);
goto err;
}
OPENSSL_free(salt);
return pbm;
err:
OPENSSL_free(salt);
OSSL_CRMF_PBMPARAMETER_free(pbm);
return NULL;
}
/*-
* calculates the PBM based on the settings of the given OSSL_CRMF_PBMPARAMETER
* |pbmp| identifies the algorithms, salt to use
* |msg| message to apply the PBM for
* |msglen| length of the message
* |sec| key to use
* |seclen| length of the key
* |out| pointer to the computed mac, will be set on success
* |outlen| if not NULL, will set variable to the length of the mac on success
* returns 1 on success, 0 on error
*/
/* could be combined with other MAC calculations in the library */
int OSSL_CRMF_pbm_new(OSSL_LIB_CTX *libctx, const char *propq,
const OSSL_CRMF_PBMPARAMETER *pbmp,
const unsigned char *msg, size_t msglen,
const unsigned char *sec, size_t seclen,
unsigned char **out, size_t *outlen)
{
int mac_nid, hmac_md_nid = NID_undef;
char mdname[OSSL_MAX_NAME_SIZE];
char hmac_mdname[OSSL_MAX_NAME_SIZE];
EVP_MD *owf = NULL;
EVP_MD_CTX *ctx = NULL;
unsigned char basekey[EVP_MAX_MD_SIZE];
unsigned int bklen = EVP_MAX_MD_SIZE;
int64_t iterations;
unsigned char *mac_res = 0;
int ok = 0;
if (out == NULL || pbmp == NULL || pbmp->mac == NULL
|| pbmp->mac->algorithm == NULL || msg == NULL || sec == NULL) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_NULL_ARGUMENT);
goto err;
}
if ((mac_res = OPENSSL_malloc(EVP_MAX_MD_SIZE)) == NULL)
goto err;
/*
* owf identifies the hash algorithm and associated parameters used to
* compute the key used in the MAC process. All implementations MUST
* support SHA-1.
*/
OBJ_obj2txt(mdname, sizeof(mdname), pbmp->owf->algorithm, 0);
if ((owf = EVP_MD_fetch(libctx, mdname, propq)) == NULL) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_UNSUPPORTED_ALGORITHM);
goto err;
}
if ((ctx = EVP_MD_CTX_new()) == NULL)
goto err;
/* compute the basekey of the salted secret */
if (!EVP_DigestInit_ex(ctx, owf, NULL))
goto err;
/* first the secret */
if (!EVP_DigestUpdate(ctx, sec, seclen))
goto err;
/* then the salt */
if (!EVP_DigestUpdate(ctx, pbmp->salt->data, pbmp->salt->length))
goto err;
if (!EVP_DigestFinal_ex(ctx, basekey, &bklen))
goto err;
if (!ASN1_INTEGER_get_int64(&iterations, pbmp->iterationCount)
|| iterations < 100 /* min from RFC */
|| iterations > OSSL_CRMF_PBM_MAX_ITERATION_COUNT) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_BAD_PBM_ITERATIONCOUNT);
goto err;
}
/* the first iteration was already done above */
while (--iterations > 0) {
if (!EVP_DigestInit_ex(ctx, owf, NULL))
goto err;
if (!EVP_DigestUpdate(ctx, basekey, bklen))
goto err;
if (!EVP_DigestFinal_ex(ctx, basekey, &bklen))
goto err;
}
/*
* mac identifies the algorithm and associated parameters of the MAC
* function to be used. All implementations MUST support HMAC-SHA1 [HMAC].
* All implementations SHOULD support DES-MAC and Triple-DES-MAC [PKCS11].
*/
mac_nid = OBJ_obj2nid(pbmp->mac->algorithm);
if (!EVP_PBE_find(EVP_PBE_TYPE_PRF, mac_nid, NULL, &hmac_md_nid, NULL)
|| OBJ_obj2txt(hmac_mdname, sizeof(hmac_mdname),
OBJ_nid2obj(hmac_md_nid), 0) <= 0) {
ERR_raise(ERR_LIB_CRMF, CRMF_R_UNSUPPORTED_ALGORITHM);
goto err;
}
/* could be generalized to allow non-HMAC: */
if (EVP_Q_mac(libctx, "HMAC", propq, hmac_mdname, NULL, basekey, bklen,
msg, msglen, mac_res, EVP_MAX_MD_SIZE, outlen) == NULL)
goto err;
ok = 1;
err:
OPENSSL_cleanse(basekey, bklen);
EVP_MD_free(owf);
EVP_MD_CTX_free(ctx);
if (ok == 1) {
*out = mac_res;
return 1;
}
OPENSSL_free(mac_res);
if (pbmp != NULL && pbmp->mac != NULL) {
char buf[128];
if (OBJ_obj2txt(buf, sizeof(buf), pbmp->mac->algorithm, 0))
ERR_add_error_data(1, buf);
}
return 0;
}
