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openssl/crypto/kdf/pbkdf2.c
Shane Lontis f0efeea29e PBKDF2 updates to conform to SP800-132 
The existing code used PKCS5 specifications.
SP800-132 adds the following additional constraints for:
  - the range of the key length.
  - the minimum iteration count (1000 recommended).
  - salt length (at least 128 bits).
These additional constraints may cause errors (in scrypt, and
some PKCS5 related test vectors). To disable the new
constraints use the new ctrl string "pkcs5".
For backwards compatability, the checks are only enabled by
default for fips mode.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8868)
2019-06-11 20:40:07 +10:00

324 lines
9.4 KiB
C
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/*
* Copyright 2018-2019 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
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <openssl/hmac.h>
#include <openssl/evp.h>
#include <openssl/kdf.h>
#include "internal/cryptlib.h"
#include "internal/evp_int.h"
#include "kdf_local.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)
/*
* For backwards compatibility reasons,
* Extra checks are done by default in fips mode only.
*/
#ifdef FIPS_MODE
# define KDF_PBKDF2_DEFAULT_CHECKS 1
#else
# define KDF_PBKDF2_DEFAULT_CHECKS 0
#endif /* FIPS_MODE */
static void kdf_pbkdf2_reset(EVP_KDF_IMPL *impl);
static void kdf_pbkdf2_init(EVP_KDF_IMPL *impl);
static int pbkdf2_derive(const char *pass, size_t passlen,
const unsigned char *salt, int saltlen, int iter,
const EVP_MD *digest, unsigned char *key,
size_t keylen, int extra_checks);
struct evp_kdf_impl_st {
unsigned char *pass;
size_t pass_len;
unsigned char *salt;
size_t salt_len;
int iter;
const EVP_MD *md;
int lower_bound_checks;
};
static EVP_KDF_IMPL *kdf_pbkdf2_new(void)
{
EVP_KDF_IMPL *impl;
impl = OPENSSL_zalloc(sizeof(*impl));
if (impl == NULL) {
KDFerr(KDF_F_KDF_PBKDF2_NEW, ERR_R_MALLOC_FAILURE);
return NULL;
}
kdf_pbkdf2_init(impl);
return impl;
}
static void kdf_pbkdf2_free(EVP_KDF_IMPL *impl)
{
kdf_pbkdf2_reset(impl);
OPENSSL_free(impl);
}
static void kdf_pbkdf2_reset(EVP_KDF_IMPL *impl)
{
OPENSSL_free(impl->salt);
OPENSSL_clear_free(impl->pass, impl->pass_len);
memset(impl, 0, sizeof(*impl));
kdf_pbkdf2_init(impl);
}
static void kdf_pbkdf2_init(EVP_KDF_IMPL *impl)
{
impl->iter = PKCS5_DEFAULT_ITER;
impl->md = EVP_sha1();
impl->lower_bound_checks = KDF_PBKDF2_DEFAULT_CHECKS;
}
static int pbkdf2_set_membuf(unsigned char **buffer, size_t *buflen,
const unsigned char *new_buffer,
size_t new_buflen)
{
if (new_buffer == NULL)
return 1;
OPENSSL_clear_free(*buffer, *buflen);
if (new_buflen > 0) {
*buffer = OPENSSL_memdup(new_buffer, new_buflen);
} else {
*buffer = OPENSSL_malloc(1);
}
if (*buffer == NULL) {
KDFerr(KDF_F_PBKDF2_SET_MEMBUF, ERR_R_MALLOC_FAILURE);
return 0;
}
*buflen = new_buflen;
return 1;
}
static int kdf_pbkdf2_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
{
int iter, pkcs5, min_iter;
const unsigned char *p;
size_t len;
const EVP_MD *md;
switch (cmd) {
case EVP_KDF_CTRL_SET_PBKDF2_PKCS5_MODE:
pkcs5 = va_arg(args, int);
impl->lower_bound_checks = (pkcs5 == 0) ? 1 : 0;
return 1;
case EVP_KDF_CTRL_SET_PASS:
p = va_arg(args, const unsigned char *);
len = va_arg(args, size_t);
return pbkdf2_set_membuf(&impl->pass, &impl->pass_len, p, len);
case EVP_KDF_CTRL_SET_SALT:
p = va_arg(args, const unsigned char *);
len = va_arg(args, size_t);
if (impl->lower_bound_checks != 0 && len < KDF_PBKDF2_MIN_SALT_LEN) {
KDFerr(KDF_F_KDF_PBKDF2_CTRL, KDF_R_INVALID_SALT_LEN);
return 0;
}
return pbkdf2_set_membuf(&impl->salt, &impl->salt_len, p, len);
case EVP_KDF_CTRL_SET_ITER:
iter = va_arg(args, int);
min_iter = impl->lower_bound_checks != 0 ? KDF_PBKDF2_MIN_ITERATIONS : 1;
if (iter < min_iter) {
KDFerr(KDF_F_KDF_PBKDF2_CTRL, KDF_R_INVALID_ITERATION_COUNT);
return 0;
}
impl->iter = iter;
return 1;
case EVP_KDF_CTRL_SET_MD:
md = va_arg(args, const EVP_MD *);
if (md == NULL) {
KDFerr(KDF_F_KDF_PBKDF2_CTRL, KDF_R_VALUE_MISSING);
return 0;
}
impl->md = md;
return 1;
default:
return -2;
}
}
static int kdf_pbkdf2_ctrl_str(EVP_KDF_IMPL *impl, const char *type,
const char *value)
{
if (value == NULL) {
KDFerr(KDF_F_KDF_PBKDF2_CTRL_STR, KDF_R_VALUE_MISSING);
return 0;
}
if (strcmp(type, "pass") == 0)
return kdf_str2ctrl(impl, kdf_pbkdf2_ctrl, EVP_KDF_CTRL_SET_PASS,
value);
if (strcmp(type, "hexpass") == 0)
return kdf_hex2ctrl(impl, kdf_pbkdf2_ctrl, EVP_KDF_CTRL_SET_PASS,
value);
if (strcmp(type, "salt") == 0)
return kdf_str2ctrl(impl, kdf_pbkdf2_ctrl, EVP_KDF_CTRL_SET_SALT,
value);
if (strcmp(type, "hexsalt") == 0)
return kdf_hex2ctrl(impl, kdf_pbkdf2_ctrl, EVP_KDF_CTRL_SET_SALT,
value);
if (strcmp(type, "iter") == 0)
return call_ctrl(kdf_pbkdf2_ctrl, impl, EVP_KDF_CTRL_SET_ITER,
atoi(value));
if (strcmp(type, "digest") == 0)
return kdf_md2ctrl(impl, kdf_pbkdf2_ctrl, EVP_KDF_CTRL_SET_MD, value);
if (strcmp(type, "pkcs5") == 0)
return kdf_str2ctrl(impl, kdf_pbkdf2_ctrl,
EVP_KDF_CTRL_SET_PBKDF2_PKCS5_MODE, value);
return -2;
}
static int kdf_pbkdf2_derive(EVP_KDF_IMPL *impl, unsigned char *key,
size_t keylen)
{
if (impl->pass == NULL) {
KDFerr(KDF_F_KDF_PBKDF2_DERIVE, KDF_R_MISSING_PASS);
return 0;
}
if (impl->salt == NULL) {
KDFerr(KDF_F_KDF_PBKDF2_DERIVE, KDF_R_MISSING_SALT);
return 0;
}
return pbkdf2_derive((char *)impl->pass, impl->pass_len,
impl->salt, impl->salt_len, impl->iter,
impl->md, key, keylen, impl->lower_bound_checks);
}
const EVP_KDF pbkdf2_kdf_meth = {
EVP_KDF_PBKDF2,
kdf_pbkdf2_new,
kdf_pbkdf2_free,
kdf_pbkdf2_reset,
kdf_pbkdf2_ctrl,
kdf_pbkdf2_ctrl_str,
NULL,
kdf_pbkdf2_derive
};
/*
* 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, int 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, j, k, tkeylen, mdlen;
unsigned long i = 1;
HMAC_CTX *hctx_tpl = NULL, *hctx = NULL;
mdlen = EVP_MD_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) {
KDFerr(KDF_F_PBKDF2_DERIVE, KDF_R_INVALID_KEY_LEN);
return 0;
}
if (lower_bound_checks) {
if ((keylen * 8) < KDF_PBKDF2_MIN_KEY_LEN_BITS) {
KDFerr(KDF_F_PBKDF2_DERIVE, KDF_R_INVALID_KEY_LEN);
return 0;
}
if (saltlen < KDF_PBKDF2_MIN_SALT_LEN) {
KDFerr(KDF_F_PBKDF2_DERIVE, KDF_R_INVALID_SALT_LEN);
return 0;
}
if (iter < KDF_PBKDF2_MIN_ITERATIONS) {
KDFerr(KDF_F_PBKDF2_DERIVE, KDF_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;
}
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