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/*-
* Copyright 2009 Colin Percival
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file was originally written by Colin Percival as part of the Tarsnap
* online backup system.
*/
#include "scrypt_platform.h"
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "sha256.h"
#include "sysendian.h"
#include "crypto_scrypt.h"
static void blkcpy(uint8_t *, uint8_t *, size_t);
static void blkxor(uint8_t *, uint8_t *, size_t);
static void salsa20_8(uint8_t[64]);
static void blockmix_salsa8(uint8_t *, uint8_t *, size_t);
static uint64_t integerify(uint8_t *, size_t);
static void smix(uint8_t *, size_t, uint64_t, uint8_t *, uint8_t *);
static void
blkcpy(uint8_t * dest, uint8_t * src, size_t len)
{
size_t i;
for (i = 0; i < len; i++)
dest[i] = src[i];
}
static void
blkxor(uint8_t * dest, uint8_t * src, size_t len)
{
size_t i;
for (i = 0; i < len; i++)
dest[i] ^= src[i];
}
/**
* salsa20_8(B):
* Apply the salsa20/8 core to the provided block.
*/
static void
salsa20_8(uint8_t B[64])
{
uint32_t B32[16];
uint32_t x[16];
size_t i;
/* Convert little-endian values in. */
for (i = 0; i < 16; i++)
B32[i] = le32dec(&B[i * 4]);
/* Compute x = doubleround^4(B32). */
for (i = 0; i < 16; i++)
x[i] = B32[i];
for (i = 0; i < 8; i += 2) {
#define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
/* Operate on columns. */
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);
/* Operate on rows. */
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);
#undef R
}
/* Compute B32 = B32 + x. */
for (i = 0; i < 16; i++)
B32[i] += x[i];
/* Convert little-endian values out. */
for (i = 0; i < 16; i++)
le32enc(&B[4 * i], B32[i]);
}
/**
* blockmix_salsa8(B, Y, r):
* Compute B = BlockMix_{salsa20/8, r}(B). The input B must be 128r bytes in
* length; the temporary space Y must also be the same size.
*/
static void
blockmix_salsa8(uint8_t * B, uint8_t * Y, size_t r)
{
uint8_t X[64];
size_t i;
/* 1: X <-- B_{2r - 1} */
blkcpy(X, &B[(2 * r - 1) * 64], 64);
/* 2: for i = 0 to 2r - 1 do */
for (i = 0; i < 2 * r; i++) {
/* 3: X <-- H(X \xor B_i) */
blkxor(X, &B[i * 64], 64);
salsa20_8(X);
/* 4: Y_i <-- X */
blkcpy(&Y[i * 64], X, 64);
}
/* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */
for (i = 0; i < r; i++)
blkcpy(&B[i * 64], &Y[(i * 2) * 64], 64);
for (i = 0; i < r; i++)
blkcpy(&B[(i + r) * 64], &Y[(i * 2 + 1) * 64], 64);
}
/**
* integerify(B, r):
* Return the result of parsing B_{2r-1} as a little-endian integer.
*/
static uint64_t
integerify(uint8_t * B, size_t r)
{
uint8_t * X = &B[(2 * r - 1) * 64];
return (le64dec(X));
}
/**
* smix(B, r, N, V, XY):
* Compute B = SMix_r(B, N). The input B must be 128r bytes in length; the
* temporary storage V must be 128rN bytes in length; the temporary storage
* XY must be 256r bytes in length. The value N must be a power of 2.
*/
static void
smix(uint8_t * B, size_t r, uint64_t N, uint8_t * V, uint8_t * XY)
{
uint8_t * X = XY;
uint8_t * Y = &XY[128 * r];
uint64_t i;
uint64_t j;
/* 1: X <-- B */
blkcpy(X, B, 128 * r);
/* 2: for i = 0 to N - 1 do */
for (i = 0; i < N; i++) {
/* 3: V_i <-- X */
blkcpy(&V[i * (128 * r)], X, 128 * r);
/* 4: X <-- H(X) */
blockmix_salsa8(X, Y, r);
}
/* 6: for i = 0 to N - 1 do */
for (i = 0; i < N; i++) {
/* 7: j <-- Integerify(X) mod N */
j = integerify(X, r) & (N - 1);
/* 8: X <-- H(X \xor V_j) */
blkxor(X, &V[j * (128 * r)], 128 * r);
blockmix_salsa8(X, Y, r);
}
/* 10: B' <-- X */
blkcpy(B, X, 128 * r);
}
/**
* crypto_scrypt(passwd, passwdlen, salt, saltlen, N, r, p, buf, buflen):
* Compute scrypt(passwd[0 .. passwdlen - 1], salt[0 .. saltlen - 1], N, r,
* p, buflen) and write the result into buf. The parameters r, p, and buflen
* must satisfy r * p < 2^30 and buflen <= (2^32 - 1) * 32. The parameter N
* must be a power of 2.
*
* Return 0 on success; or -1 on error.
*/
int
crypto_scrypt(const uint8_t * passwd, size_t passwdlen,
const uint8_t * salt, size_t saltlen, uint64_t N, uint32_t _r, uint32_t _p,
uint8_t * buf, size_t buflen)
{
uint8_t * B;
uint8_t * V;
uint8_t * XY;
size_t r = _r, p = _p;
uint32_t i;
/* Sanity-check parameters. */
#if SIZE_MAX > UINT32_MAX
if (buflen > (((uint64_t)(1) << 32) - 1) * 32) {
errno = EFBIG;
goto err0;
}
#endif
if ((uint64_t)(r) * (uint64_t)(p) >= (1 << 30)) {
errno = EFBIG;
goto err0;
}
if (((N & (N - 1)) != 0) || (N == 0)) {
errno = EINVAL;
goto err0;
}
if ((r > SIZE_MAX / 128 / p) ||
#if SIZE_MAX / 256 <= UINT32_MAX
(r > SIZE_MAX / 256) ||
#endif
(N > SIZE_MAX / 128 / r)) {
errno = ENOMEM;
goto err0;
}
/* Allocate memory. */
if ((B = malloc(128 * r * p)) == NULL)
goto err0;
if ((XY = malloc(256 * r)) == NULL)
goto err1;
if ((V = malloc(128 * r * N)) == NULL)
goto err2;
/* 1: (B_0 ... B_{p-1}) <-- PBKDF2(P, S, 1, p * MFLen) */
PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, 1, B, p * 128 * r);
/* 2: for i = 0 to p - 1 do */
for (i = 0; i < p; i++) {
/* 3: B_i <-- MF(B_i, N) */
smix(&B[i * 128 * r], r, N, V, XY);
}
/* 5: DK <-- PBKDF2(P, B, 1, dkLen) */
PBKDF2_SHA256(passwd, passwdlen, B, p * 128 * r, 1, buf, buflen);
/* Free memory. */
free(V);
free(XY);
free(B);
/* Success! */
return (0);
err2:
free(XY);
err1:
free(B);
err0:
/* Failure! */
return (-1);
}