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/*
* 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 <string.h>
#include <openssl/hmac.h>
#include <openssl/kdf.h>
#include <openssl/evp.h>
#include "internal/cryptlib.h"
#include "internal/evp_int.h"
#ifndef OPENSSL_NO_SCRYPT
static int atou64(const char *nptr, uint64_t *result);
typedef struct {
unsigned char *pass;
size_t pass_len;
unsigned char *salt;
size_t salt_len;
uint64_t N, r, p;
uint64_t maxmem_bytes;
} SCRYPT_PKEY_CTX;
/* 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 int pkey_scrypt_init(EVP_PKEY_CTX *ctx)
{
SCRYPT_PKEY_CTX *kctx;
kctx = OPENSSL_zalloc(sizeof(*kctx));
if (kctx == NULL) {
KDFerr(KDF_F_PKEY_SCRYPT_INIT, ERR_R_MALLOC_FAILURE);
return 0;
}
/* 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).
*/
kctx->N = 1 << 20;
kctx->r = 8;
kctx->p = 1;
kctx->maxmem_bytes = 1025 * 1024 * 1024;
ctx->data = kctx;
return 1;
}
static void pkey_scrypt_cleanup(EVP_PKEY_CTX *ctx)
{
SCRYPT_PKEY_CTX *kctx = ctx->data;
OPENSSL_clear_free(kctx->salt, kctx->salt_len);
OPENSSL_clear_free(kctx->pass, kctx->pass_len);
OPENSSL_free(kctx);
}
static int pkey_scrypt_set_membuf(unsigned char **buffer, size_t *buflen,
const unsigned char *new_buffer,
const int new_buflen)
{
if (new_buffer == NULL)
return 1;
if (new_buflen < 0)
return 0;
if (*buffer != NULL)
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_PKEY_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 pkey_scrypt_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
{
SCRYPT_PKEY_CTX *kctx = ctx->data;
uint64_t u64_value;
switch (type) {
case EVP_PKEY_CTRL_PASS:
return pkey_scrypt_set_membuf(&kctx->pass, &kctx->pass_len, p2, p1);
case EVP_PKEY_CTRL_SCRYPT_SALT:
return pkey_scrypt_set_membuf(&kctx->salt, &kctx->salt_len, p2, p1);
case EVP_PKEY_CTRL_SCRYPT_N:
u64_value = *((uint64_t *)p2);
if ((u64_value <= 1) || !is_power_of_two(u64_value))
return 0;
kctx->N = u64_value;
return 1;
case EVP_PKEY_CTRL_SCRYPT_R:
u64_value = *((uint64_t *)p2);
if (u64_value < 1)
return 0;
kctx->r = u64_value;
return 1;
case EVP_PKEY_CTRL_SCRYPT_P:
u64_value = *((uint64_t *)p2);
if (u64_value < 1)
return 0;
kctx->p = u64_value;
return 1;
case EVP_PKEY_CTRL_SCRYPT_MAXMEM_BYTES:
u64_value = *((uint64_t *)p2);
if (u64_value < 1)
return 0;
kctx->maxmem_bytes = u64_value;
return 1;
default:
return -2;
}
}
static int pkey_scrypt_ctrl_uint64(EVP_PKEY_CTX *ctx, int type,
const char *value)
{
uint64_t int_value;
if (!atou64(value, &int_value)) {
KDFerr(KDF_F_PKEY_SCRYPT_CTRL_UINT64, KDF_R_VALUE_ERROR);
return 0;
}
return pkey_scrypt_ctrl(ctx, type, 0, &int_value);
}
static int pkey_scrypt_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
const char *value)
{
if (value == NULL) {
KDFerr(KDF_F_PKEY_SCRYPT_CTRL_STR, KDF_R_VALUE_MISSING);
return 0;
}
if (strcmp(type, "pass") == 0)
return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_PASS, value);
if (strcmp(type, "hexpass") == 0)
return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_PASS, value);
if (strcmp(type, "salt") == 0)
return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_SCRYPT_SALT, value);
if (strcmp(type, "hexsalt") == 0)
return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_SCRYPT_SALT, value);
if (strcmp(type, "N") == 0)
return pkey_scrypt_ctrl_uint64(ctx, EVP_PKEY_CTRL_SCRYPT_N, value);
if (strcmp(type, "r") == 0)
return pkey_scrypt_ctrl_uint64(ctx, EVP_PKEY_CTRL_SCRYPT_R, value);
if (strcmp(type, "p") == 0)
return pkey_scrypt_ctrl_uint64(ctx, EVP_PKEY_CTRL_SCRYPT_P, value);
if (strcmp(type, "maxmem_bytes") == 0)
return pkey_scrypt_ctrl_uint64(ctx, EVP_PKEY_CTRL_SCRYPT_MAXMEM_BYTES,
value);
KDFerr(KDF_F_PKEY_SCRYPT_CTRL_STR, KDF_R_UNKNOWN_PARAMETER_TYPE);
return -2;
}
static int pkey_scrypt_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
size_t *keylen)
{
SCRYPT_PKEY_CTX *kctx = ctx->data;
if (kctx->pass == NULL) {
KDFerr(KDF_F_PKEY_SCRYPT_DERIVE, KDF_R_MISSING_PASS);
return 0;
}
if (kctx->salt == NULL) {
KDFerr(KDF_F_PKEY_SCRYPT_DERIVE, KDF_R_MISSING_SALT);
return 0;
}
return EVP_PBE_scrypt((char *)kctx->pass, kctx->pass_len, kctx->salt,
kctx->salt_len, kctx->N, kctx->r, kctx->p,
kctx->maxmem_bytes, key, *keylen);
}
const EVP_PKEY_METHOD scrypt_pkey_meth = {
EVP_PKEY_SCRYPT,
0,
pkey_scrypt_init,
0,
pkey_scrypt_cleanup,
0, 0,
0, 0,
0,
0,
0,
0,
0, 0,
0, 0, 0, 0,
0, 0,
0, 0,
0,
pkey_scrypt_derive,
pkey_scrypt_ctrl,
pkey_scrypt_ctrl_str
};
#endif
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