pbkdf2.c
/*
* Copyright 2018-2023 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
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/*
* HMAC low level APIs are deprecated for public use, but still ok for internal
* use.
*/
#include "internal/deprecated.h"
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <openssl/hmac.h>
#include <openssl/evp.h>
#include <openssl/kdf.h>
#include <openssl/core_names.h>
#include <openssl/proverr.h>
#include "internal/cryptlib.h"
#include "internal/numbers.h"
#include "crypto/evp.h"
#include "prov/provider_ctx.h"
#include "prov/providercommon.h"
#include "prov/implementations.h"
#include "prov/provider_util.h"
#include "pbkdf2.h"
/* Constants specified in SP800-132 */
#define KDF_PBKDF2_MIN_KEY_LEN_BITS 112
#define KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO 0xFFFFFFFF
#define KDF_PBKDF2_MIN_ITERATIONS 1000
#define KDF_PBKDF2_MIN_SALT_LEN (128 / 8)
static OSSL_FUNC_kdf_newctx_fn kdf_pbkdf2_new;
static OSSL_FUNC_kdf_dupctx_fn kdf_pbkdf2_dup;
static OSSL_FUNC_kdf_freectx_fn kdf_pbkdf2_free;
static OSSL_FUNC_kdf_reset_fn kdf_pbkdf2_reset;
static OSSL_FUNC_kdf_derive_fn kdf_pbkdf2_derive;
static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_pbkdf2_settable_ctx_params;
static OSSL_FUNC_kdf_set_ctx_params_fn kdf_pbkdf2_set_ctx_params;
static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_pbkdf2_gettable_ctx_params;
static OSSL_FUNC_kdf_get_ctx_params_fn kdf_pbkdf2_get_ctx_params;
static int pbkdf2_derive(const char *pass, size_t passlen,
const unsigned char *salt, int saltlen, uint64_t iter,
const EVP_MD *digest, unsigned char *key,
size_t keylen, int extra_checks);
typedef struct {
void *provctx;
unsigned char *pass;
size_t pass_len;
unsigned char *salt;
size_t salt_len;
uint64_t iter;
PROV_DIGEST digest;
int lower_bound_checks;
} KDF_PBKDF2;
static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx);
static void *kdf_pbkdf2_new_no_init(void *provctx)
{
KDF_PBKDF2 *ctx;
if (!ossl_prov_is_running())
return NULL;
ctx = OPENSSL_zalloc(sizeof(*ctx));
if (ctx == NULL)
return NULL;
ctx->provctx = provctx;
return ctx;
}
static void *kdf_pbkdf2_new(void *provctx)
{
KDF_PBKDF2 *ctx = kdf_pbkdf2_new_no_init(provctx);
if (ctx != NULL)
kdf_pbkdf2_init(ctx);
return ctx;
}
static void kdf_pbkdf2_cleanup(KDF_PBKDF2 *ctx)
{
ossl_prov_digest_reset(&ctx->digest);
OPENSSL_free(ctx->salt);
OPENSSL_clear_free(ctx->pass, ctx->pass_len);
memset(ctx, 0, sizeof(*ctx));
}
static void kdf_pbkdf2_free(void *vctx)
{
KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
if (ctx != NULL) {
kdf_pbkdf2_cleanup(ctx);
OPENSSL_free(ctx);
}
}
static void kdf_pbkdf2_reset(void *vctx)
{
KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
void *provctx = ctx->provctx;
kdf_pbkdf2_cleanup(ctx);
ctx->provctx = provctx;
kdf_pbkdf2_init(ctx);
}
static void *kdf_pbkdf2_dup(void *vctx)
{
const KDF_PBKDF2 *src = (const KDF_PBKDF2 *)vctx;
KDF_PBKDF2 *dest;
/* We need a new PBKDF2 object but uninitialised since we're filling it */
dest = kdf_pbkdf2_new_no_init(src->provctx);
if (dest != NULL) {
if (!ossl_prov_memdup(src->salt, src->salt_len,
&dest->salt, &dest->salt_len)
|| !ossl_prov_memdup(src->pass, src->pass_len,
&dest->pass, &dest->pass_len)
|| !ossl_prov_digest_copy(&dest->digest, &src->digest))
goto err;
dest->iter = src->iter;
dest->lower_bound_checks = src->lower_bound_checks;
}
return dest;
err:
kdf_pbkdf2_free(dest);
return NULL;
}
static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx)
{
OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
params[0] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
SN_sha1, 0);
if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
/* This is an error, but there is no way to indicate such directly */
ossl_prov_digest_reset(&ctx->digest);
ctx->iter = PKCS5_DEFAULT_ITER;
ctx->lower_bound_checks = ossl_kdf_pbkdf2_default_checks;
}
static int pbkdf2_set_membuf(unsigned char **buffer, size_t *buflen,
const OSSL_PARAM *p)
{
OPENSSL_clear_free(*buffer, *buflen);
*buffer = NULL;
*buflen = 0;
if (p->data_size == 0) {
if ((*buffer = OPENSSL_malloc(1)) == NULL)
return 0;
} else if (p->data != NULL) {
if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
return 0;
}
return 1;
}
static int kdf_pbkdf2_derive(void *vctx, unsigned char *key, size_t keylen,
const OSSL_PARAM params[])
{
KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
const EVP_MD *md;
if (!ossl_prov_is_running() || !kdf_pbkdf2_set_ctx_params(ctx, params))
return 0;
if (ctx->pass == NULL) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
return 0;
}
if (ctx->salt == NULL) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
return 0;
}
md = ossl_prov_digest_md(&ctx->digest);
return pbkdf2_derive((char *)ctx->pass, ctx->pass_len,
ctx->salt, ctx->salt_len, ctx->iter,
md, key, keylen, ctx->lower_bound_checks);
}
static int kdf_pbkdf2_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
const OSSL_PARAM *p;
KDF_PBKDF2 *ctx = vctx;
OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
int pkcs5;
uint64_t iter, min_iter;
if (params == NULL)
return 1;
if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
return 0;
if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PKCS5)) != NULL) {
if (!OSSL_PARAM_get_int(p, &pkcs5))
return 0;
ctx->lower_bound_checks = pkcs5 == 0;
}
if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
if (!pbkdf2_set_membuf(&ctx->pass, &ctx->pass_len, p))
return 0;
if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL) {
if (ctx->lower_bound_checks != 0
&& p->data_size < KDF_PBKDF2_MIN_SALT_LEN) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SALT_LENGTH);
return 0;
}
if (!pbkdf2_set_membuf(&ctx->salt, &ctx->salt_len, p))
return 0;
}
if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_ITER)) != NULL) {
if (!OSSL_PARAM_get_uint64(p, &iter))
return 0;
min_iter = ctx->lower_bound_checks != 0 ? KDF_PBKDF2_MIN_ITERATIONS : 1;
if (iter < min_iter) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);
return 0;
}
ctx->iter = iter;
}
return 1;
}
static const OSSL_PARAM *kdf_pbkdf2_settable_ctx_params(ossl_unused void *ctx,
ossl_unused void *p_ctx)
{
static const OSSL_PARAM known_settable_ctx_params[] = {
OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
OSSL_PARAM_uint64(OSSL_KDF_PARAM_ITER, NULL),
OSSL_PARAM_int(OSSL_KDF_PARAM_PKCS5, NULL),
OSSL_PARAM_END
};
return known_settable_ctx_params;
}
static int kdf_pbkdf2_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
OSSL_PARAM *p;
if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
return OSSL_PARAM_set_size_t(p, SIZE_MAX);
return -2;
}
static const OSSL_PARAM *kdf_pbkdf2_gettable_ctx_params(ossl_unused void *ctx,
ossl_unused void *p_ctx)
{
static const OSSL_PARAM known_gettable_ctx_params[] = {
OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
OSSL_PARAM_END
};
return known_gettable_ctx_params;
}
const OSSL_DISPATCH ossl_kdf_pbkdf2_functions[] = {
{ OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_pbkdf2_new },
{ OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kdf_pbkdf2_dup },
{ OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_pbkdf2_free },
{ OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_pbkdf2_reset },
{ OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_pbkdf2_derive },
{ OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
(void(*)(void))kdf_pbkdf2_settable_ctx_params },
{ OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_set_ctx_params },
{ OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
(void(*)(void))kdf_pbkdf2_gettable_ctx_params },
{ OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_get_ctx_params },
OSSL_DISPATCH_END
};
/*
* This is an implementation of PKCS#5 v2.0 password based encryption key
* derivation function PBKDF2. SHA1 version verified against test vectors
* posted by Peter Gutmann to the PKCS-TNG mailing list.
*
* The constraints specified by SP800-132 have been added i.e.
* - Check the range of the key length.
* - Minimum iteration count of 1000.
* - Randomly-generated portion of the salt shall be at least 128 bits.
*/
static int pbkdf2_derive(const char *pass, size_t passlen,
const unsigned char *salt, int saltlen, uint64_t iter,
const EVP_MD *digest, unsigned char *key,
size_t keylen, int lower_bound_checks)
{
int ret = 0;
unsigned char digtmp[EVP_MAX_MD_SIZE], *p, itmp[4];
int cplen, k, tkeylen, mdlen;
uint64_t j;
unsigned long i = 1;
HMAC_CTX *hctx_tpl = NULL, *hctx = NULL;
mdlen = EVP_MD_get_size(digest);
if (mdlen <= 0)
return 0;
/*
* This check should always be done because keylen / mdlen >= (2^32 - 1)
* results in an overflow of the loop counter 'i'.
*/
if ((keylen / mdlen) >= KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
return 0;
}
if (lower_bound_checks) {
if ((keylen * 8) < KDF_PBKDF2_MIN_KEY_LEN_BITS) {
ERR_raise(ERR_LIB_PROV, PROV_R_KEY_SIZE_TOO_SMALL);
return 0;
}
if (saltlen < KDF_PBKDF2_MIN_SALT_LEN) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SALT_LENGTH);
return 0;
}
if (iter < KDF_PBKDF2_MIN_ITERATIONS) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);
return 0;
}
}
hctx_tpl = HMAC_CTX_new();
if (hctx_tpl == NULL)
return 0;
p = key;
tkeylen = keylen;
if (!HMAC_Init_ex(hctx_tpl, pass, passlen, digest, NULL))
goto err;
hctx = HMAC_CTX_new();
if (hctx == NULL)
goto err;
while (tkeylen) {
if (tkeylen > mdlen)
cplen = mdlen;
else
cplen = tkeylen;
/*
* We are unlikely to ever use more than 256 blocks (5120 bits!) but
* just in case...
*/
itmp[0] = (unsigned char)((i >> 24) & 0xff);
itmp[1] = (unsigned char)((i >> 16) & 0xff);
itmp[2] = (unsigned char)((i >> 8) & 0xff);
itmp[3] = (unsigned char)(i & 0xff);
if (!HMAC_CTX_copy(hctx, hctx_tpl))
goto err;
if (!HMAC_Update(hctx, salt, saltlen)
|| !HMAC_Update(hctx, itmp, 4)
|| !HMAC_Final(hctx, digtmp, NULL))
goto err;
memcpy(p, digtmp, cplen);
for (j = 1; j < iter; j++) {
if (!HMAC_CTX_copy(hctx, hctx_tpl))
goto err;
if (!HMAC_Update(hctx, digtmp, mdlen)
|| !HMAC_Final(hctx, digtmp, NULL))
goto err;
for (k = 0; k < cplen; k++)
p[k] ^= digtmp[k];
}
tkeylen -= cplen;
i++;
p += cplen;
}
ret = 1;
err:
HMAC_CTX_free(hctx);
HMAC_CTX_free(hctx_tpl);
return ret;
}
