/*
* Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (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/kdf.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include "crypto/evp.h"
#include "internal/numbers.h"
#include "kdf_local.h"
#ifndef OPENSSL_NO_SCRYPT
static void kdf_scrypt_reset(EVP_KDF_IMPL *impl);
static void kdf_scrypt_init(EVP_KDF_IMPL *impl);
static int atou64(const char *nptr, uint64_t *result);
static int scrypt_alg(const char *pass, size_t passlen,
const unsigned char *salt, size_t saltlen,
uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
unsigned char *key, size_t keylen);
struct evp_kdf_impl_st {
unsigned char *pass;
size_t pass_len;
unsigned char *salt;
size_t salt_len;
uint64_t N;
uint32_t r, p;
uint64_t maxmem_bytes;
};
/* Custom uint64_t parser since we do not have strtoull */
static int atou64(const char *nptr, uint64_t *result)
{
uint64_t value = 0;
while (*nptr) {
unsigned int digit;
uint64_t new_value;
if ((*nptr < '0') || (*nptr > '9')) {
return 0;
}
digit = (unsigned int)(*nptr - '0');
new_value = (value * 10) + digit;
if ((new_value < digit) || ((new_value - digit) / 10 != value)) {
/* Overflow */
return 0;
}
value = new_value;
nptr++;
}
*result = value;
return 1;
}
static EVP_KDF_IMPL *kdf_scrypt_new(void)
{
EVP_KDF_IMPL *impl;
impl = OPENSSL_zalloc(sizeof(*impl));
if (impl == NULL) {
KDFerr(KDF_F_KDF_SCRYPT_NEW, ERR_R_MALLOC_FAILURE);
return NULL;
}
kdf_scrypt_init(impl);
return impl;
}
static void kdf_scrypt_free(EVP_KDF_IMPL *impl)
{
kdf_scrypt_reset(impl);
OPENSSL_free(impl);
}
static void kdf_scrypt_reset(EVP_KDF_IMPL *impl)
{
OPENSSL_free(impl->salt);
OPENSSL_clear_free(impl->pass, impl->pass_len);
memset(impl, 0, sizeof(*impl));
kdf_scrypt_init(impl);
}
static void kdf_scrypt_init(EVP_KDF_IMPL *impl)
{
/* Default values are the most conservative recommendation given in the
* original paper of C. Percival. Derivation uses roughly 1 GiB of memory
* for this parameter choice (approx. 128 * r * N * p bytes).
*/
impl->N = 1 << 20;
impl->r = 8;
impl->p = 1;
impl->maxmem_bytes = 1025 * 1024 * 1024;
}
static int scrypt_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_SCRYPT_SET_MEMBUF, ERR_R_MALLOC_FAILURE);
return 0;
}
*buflen = new_buflen;
return 1;
}
static int is_power_of_two(uint64_t value)
{
return (value != 0) && ((value & (value - 1)) == 0);
}
static int kdf_scrypt_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
{
uint64_t u64_value;
uint32_t value;
const unsigned char *p;
size_t len;
switch (cmd) {
case EVP_KDF_CTRL_SET_PASS:
p = va_arg(args, const unsigned char *);
len = va_arg(args, size_t);
return scrypt_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);
return scrypt_set_membuf(&impl->salt, &impl->salt_len, p, len);
case EVP_KDF_CTRL_SET_SCRYPT_N:
u64_value = va_arg(args, uint64_t);
if ((u64_value <= 1) || !is_power_of_two(u64_value))
return 0;
impl->N = u64_value;
return 1;
case EVP_KDF_CTRL_SET_SCRYPT_R:
value = va_arg(args, uint32_t);
if (value < 1)
return 0;
impl->r = value;
return 1;
case EVP_KDF_CTRL_SET_SCRYPT_P:
value = va_arg(args, uint32_t);
if (value < 1)
return 0;
impl->p = value;
return 1;
case EVP_KDF_CTRL_SET_MAXMEM_BYTES:
u64_value = va_arg(args, uint64_t);
if (u64_value < 1)
return 0;
impl->maxmem_bytes = u64_value;
return 1;
default:
return -2;
}
}
static int kdf_scrypt_ctrl_uint32(EVP_KDF_IMPL *impl, int cmd,
const char *value)
{
int int_value = atoi(value);
if (int_value < 0 || (uint64_t)int_value > UINT32_MAX) {
KDFerr(KDF_F_KDF_SCRYPT_CTRL_UINT32, KDF_R_VALUE_ERROR);
return 0;
}
return call_ctrl(kdf_scrypt_ctrl, impl, cmd, (uint32_t)int_value);
}
static int kdf_scrypt_ctrl_uint64(EVP_KDF_IMPL *impl, int cmd,
const char *value)
{
uint64_t u64_value;
if (!atou64(value, &u64_value)) {
KDFerr(KDF_F_KDF_SCRYPT_CTRL_UINT64, KDF_R_VALUE_ERROR);
return 0;
}
return call_ctrl(kdf_scrypt_ctrl, impl, cmd, u64_value);
}
static int kdf_scrypt_ctrl_str(EVP_KDF_IMPL *impl, const char *type,
const char *value)
{
if (value == NULL) {
KDFerr(KDF_F_KDF_SCRYPT_CTRL_STR, KDF_R_VALUE_MISSING);
return 0;
}
if (strcmp(type, "pass") == 0)
return kdf_str2ctrl(impl, kdf_scrypt_ctrl, EVP_KDF_CTRL_SET_PASS,
value);
if (strcmp(type, "hexpass") == 0)
return kdf_hex2ctrl(impl, kdf_scrypt_ctrl, EVP_KDF_CTRL_SET_PASS,
value);
if (strcmp(type, "salt") == 0)
return kdf_str2ctrl(impl, kdf_scrypt_ctrl, EVP_KDF_CTRL_SET_SALT,
value);
if (strcmp(type, "hexsalt") == 0)
return kdf_hex2ctrl(impl, kdf_scrypt_ctrl, EVP_KDF_CTRL_SET_SALT,
value);
if (strcmp(type, "N") == 0)
return kdf_scrypt_ctrl_uint64(impl, EVP_KDF_CTRL_SET_SCRYPT_N, value);
if (strcmp(type, "r") == 0)
return kdf_scrypt_ctrl_uint32(impl, EVP_KDF_CTRL_SET_SCRYPT_R, value);
if (strcmp(type, "p") == 0)
return kdf_scrypt_ctrl_uint32(impl, EVP_KDF_CTRL_SET_SCRYPT_P, value);
if (strcmp(type, "maxmem_bytes") == 0)
return kdf_scrypt_ctrl_uint64(impl, EVP_KDF_CTRL_SET_MAXMEM_BYTES,
value);
return -2;
}
static int kdf_scrypt_derive(EVP_KDF_IMPL *impl, unsigned char *key,
size_t keylen)
{
if (impl->pass == NULL) {
KDFerr(KDF_F_KDF_SCRYPT_DERIVE, KDF_R_MISSING_PASS);
return 0;
}
if (impl->salt == NULL) {
KDFerr(KDF_F_KDF_SCRYPT_DERIVE, KDF_R_MISSING_SALT);
return 0;
}
return scrypt_alg((char *)impl->pass, impl->pass_len, impl->salt,
impl->salt_len, impl->N, impl->r, impl->p,
impl->maxmem_bytes, key, keylen);
}
const EVP_KDF_METHOD scrypt_kdf_meth = {
EVP_KDF_SCRYPT,
kdf_scrypt_new,
kdf_scrypt_free,
kdf_scrypt_reset,
kdf_scrypt_ctrl,
kdf_scrypt_ctrl_str,
NULL,
kdf_scrypt_derive
};
#define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
static void salsa208_word_specification(uint32_t inout[16])
{
int i;
uint32_t x[16];
memcpy(x, inout, sizeof(x));
for (i = 8; i > 0; i -= 2) {
x[4] ^= R(x[0] + x[12], 7);
x[8] ^= R(x[4] + x[0], 9);
x[12] ^= R(x[8] + x[4], 13);
x[0] ^= R(x[12] + x[8], 18);
x[9] ^= R(x[5] + x[1], 7);
x[13] ^= R(x[9] + x[5], 9);
x[1] ^= R(x[13] + x[9], 13);
x[5] ^= R(x[1] + x[13], 18);
x[14] ^= R(x[10] + x[6], 7);
x[2] ^= R(x[14] + x[10], 9);
x[6] ^= R(x[2] + x[14], 13);
x[10] ^= R(x[6] + x[2], 18);
x[3] ^= R(x[15] + x[11], 7);
x[7] ^= R(x[3] + x[15], 9);
x[11] ^= R(x[7] + x[3], 13);
x[15] ^= R(x[11] + x[7], 18);
x[1] ^= R(x[0] + x[3], 7);
x[2] ^= R(x[1] + x[0], 9);
x[3] ^= R(x[2] + x[1], 13);
x[0] ^= R(x[3] + x[2], 18);
x[6] ^= R(x[5] + x[4], 7);
x[7] ^= R(x[6] + x[5], 9);
x[4] ^= R(x[7] + x[6], 13);
x[5] ^= R(x[4] + x[7], 18);
x[11] ^= R(x[10] + x[9], 7);
x[8] ^= R(x[11] + x[10], 9);
x[9] ^= R(x[8] + x[11], 13);
x[10] ^= R(x[9] + x[8], 18);
x[12] ^= R(x[15] + x[14], 7);
x[13] ^= R(x[12] + x[15], 9);
x[14] ^= R(x[13] + x[12], 13);
x[15] ^= R(x[14] + x[13], 18);
}
for (i = 0; i < 16; ++i)
inout[i] += x[i];
OPENSSL_cleanse(x, sizeof(x));
}
static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)
{
uint64_t i, j;
uint32_t X[16], *pB;
memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));
pB = B;
for (i = 0; i < r * 2; i++) {
for (j = 0; j < 16; j++)
X[j] ^= *pB++;
salsa208_word_specification(X);
memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));
}
OPENSSL_cleanse(X, sizeof(X));
}
static void scryptROMix(unsigned char *B, uint64_t r, uint64_t N,
uint32_t *X, uint32_t *T, uint32_t *V)
{
unsigned char *pB;
uint32_t *pV;
uint64_t i, k;
/* Convert from little endian input */
for (pV = V, i = 0, pB = B; i < 32 * r; i++, pV++) {
*pV = *pB++;
*pV |= *pB++ << 8;
*pV |= *pB++ << 16;
*pV |= (uint32_t)*pB++ << 24;
}
for (i = 1; i < N; i++, pV += 32 * r)
scryptBlockMix(pV, pV - 32 * r, r);
scryptBlockMix(X, V + (N - 1) * 32 * r, r);
for (i = 0; i < N; i++) {
uint32_t j;
j = X[16 * (2 * r - 1)] % N;
pV = V + 32 * r * j;
for (k = 0; k < 32 * r; k++)
T[k] = X[k] ^ *pV++;
scryptBlockMix(X, T, r);
}
/* Convert output to little endian */
for (i = 0, pB = B; i < 32 * r; i++) {
uint32_t xtmp = X[i];
*pB++ = xtmp & 0xff;
*pB++ = (xtmp >> 8) & 0xff;
*pB++ = (xtmp >> 16) & 0xff;
*pB++ = (xtmp >> 24) & 0xff;
}
}
#ifndef SIZE_MAX
# define SIZE_MAX ((size_t)-1)
#endif
/*
* Maximum power of two that will fit in uint64_t: this should work on
* most (all?) platforms.
*/
#define LOG2_UINT64_MAX (sizeof(uint64_t) * 8 - 1)
/*
* Maximum value of p * r:
* p <= ((2^32-1) * hLen) / MFLen =>
* p <= ((2^32-1) * 32) / (128 * r) =>
* p * r <= (2^30-1)
*/
#define SCRYPT_PR_MAX ((1 << 30) - 1)
static int scrypt_alg(const char *pass, size_t passlen,
const unsigned char *salt, size_t saltlen,
uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
unsigned char *key, size_t keylen)
{
int rv = 0;
unsigned char *B;
uint32_t *X, *V, *T;
uint64_t i, Blen, Vlen;
/* Sanity check parameters */
/* initial check, r,p must be non zero, N >= 2 and a power of 2 */
if (r == 0 || p == 0 || N < 2 || (N & (N - 1)))
return 0;
/* Check p * r < SCRYPT_PR_MAX avoiding overflow */
if (p > SCRYPT_PR_MAX / r) {
EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
return 0;
}
/*
* Need to check N: if 2^(128 * r / 8) overflows limit this is
* automatically satisfied since N <= UINT64_MAX.
*/
if (16 * r <= LOG2_UINT64_MAX) {
if (N >= (((uint64_t)1) << (16 * r))) {
EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
return 0;
}
}
/* Memory checks: check total allocated buffer size fits in uint64_t */
/*
* B size in section 5 step 1.S
* Note: we know p * 128 * r < UINT64_MAX because we already checked
* p * r < SCRYPT_PR_MAX
*/
Blen = p * 128 * r;
/*
* Yet we pass it as integer to PKCS5_PBKDF2_HMAC... [This would
* have to be revised when/if PKCS5_PBKDF2_HMAC accepts size_t.]
*/
if (Blen > INT_MAX) {
EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
return 0;
}
/*
* Check 32 * r * (N + 2) * sizeof(uint32_t) fits in uint64_t
* This is combined size V, X and T (section 4)
*/
i = UINT64_MAX / (32 * sizeof(uint32_t));
if (N + 2 > i / r) {
EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
return 0;
}
Vlen = 32 * r * (N + 2) * sizeof(uint32_t);
/* check total allocated size fits in uint64_t */
if (Blen > UINT64_MAX - Vlen) {
EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
return 0;
}
/* Check that the maximum memory doesn't exceed a size_t limits */
if (maxmem > SIZE_MAX)
maxmem = SIZE_MAX;
if (Blen + Vlen > maxmem) {
EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
return 0;
}
/* If no key return to indicate parameters are OK */
if (key == NULL)
return 1;
B = OPENSSL_malloc((size_t)(Blen + Vlen));
if (B == NULL) {
EVPerr(EVP_F_SCRYPT_ALG, ERR_R_MALLOC_FAILURE);
return 0;
}
X = (uint32_t *)(B + Blen);
T = X + 32 * r;
V = T + 32 * r;
if (PKCS5_PBKDF2_HMAC(pass, passlen, salt, saltlen, 1, EVP_sha256(),
(int)Blen, B) == 0)
goto err;
for (i = 0; i < p; i++)
scryptROMix(B + 128 * r * i, r, N, X, T, V);
if (PKCS5_PBKDF2_HMAC(pass, passlen, B, (int)Blen, 1, EVP_sha256(),
keylen, key) == 0)
goto err;
rv = 1;
err:
if (rv == 0)
EVPerr(EVP_F_SCRYPT_ALG, EVP_R_PBKDF2_ERROR);
OPENSSL_clear_free(B, (size_t)(Blen + Vlen));
return rv;
}
const EVP_PKEY_METHOD *scrypt_pkey_method(void)
{
return &scrypt_pkey_meth;
}
#endif