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/*-
* Copyright 2005,2007,2009 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.
*/
#include <sys/types.h>
#include <stdint.h>
#include <string.h>
#include "sysendian.h"
#include "sha256.h"
/*
* Encode a length len/4 vector of (uint32_t) into a length len vector of
* (unsigned char) in big-endian form. Assumes len is a multiple of 4.
*/
static void
be32enc_vect(unsigned char *dst, const uint32_t *src, size_t len)
{
size_t i;
for (i = 0; i < len / 4; i++)
be32enc(dst + i * 4, src[i]);
}
/*
* Decode a big-endian length len vector of (unsigned char) into a length
* len/4 vector of (uint32_t). Assumes len is a multiple of 4.
*/
static void
be32dec_vect(uint32_t *dst, const unsigned char *src, size_t len)
{
size_t i;
for (i = 0; i < len / 4; i++)
dst[i] = be32dec(src + i * 4);
}
/* Elementary functions used by SHA256 */
#define Ch(x, y, z) ((x & (y ^ z)) ^ z)
#define Maj(x, y, z) ((x & (y | z)) | (y & z))
#define SHR(x, n) (x >> n)
#define ROTR(x, n) ((x >> n) | (x << (32 - n)))
#define S0(x) (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define S1(x) (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
#define s0(x) (ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3))
#define s1(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10))
/* SHA256 round function */
#define RND(a, b, c, d, e, f, g, h, k) \
t0 = h + S1(e) + Ch(e, f, g) + k; \
t1 = S0(a) + Maj(a, b, c); \
d += t0; \
h = t0 + t1;
/* Adjusted round function for rotating state */
#define RNDr(S, W, i, k) \
RND(S[(64 - i) % 8], S[(65 - i) % 8], \
S[(66 - i) % 8], S[(67 - i) % 8], \
S[(68 - i) % 8], S[(69 - i) % 8], \
S[(70 - i) % 8], S[(71 - i) % 8], \
W[i] + k)
/*
* SHA256 block compression function. The 256-bit state is transformed via
* the 512-bit input block to produce a new state.
*/
static void
SHA256_Transform(uint32_t * state, const unsigned char block[64])
{
uint32_t W[64];
uint32_t S[8];
uint32_t t0, t1;
int i;
/* 1. Prepare message schedule W. */
be32dec_vect(W, block, 64);
for (i = 16; i < 64; i++)
W[i] = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16];
/* 2. Initialize working variables. */
memcpy(S, state, 32);
/* 3. Mix. */
RNDr(S, W, 0, 0x428a2f98);
RNDr(S, W, 1, 0x71374491);
RNDr(S, W, 2, 0xb5c0fbcf);
RNDr(S, W, 3, 0xe9b5dba5);
RNDr(S, W, 4, 0x3956c25b);
RNDr(S, W, 5, 0x59f111f1);
RNDr(S, W, 6, 0x923f82a4);
RNDr(S, W, 7, 0xab1c5ed5);
RNDr(S, W, 8, 0xd807aa98);
RNDr(S, W, 9, 0x12835b01);
RNDr(S, W, 10, 0x243185be);
RNDr(S, W, 11, 0x550c7dc3);
RNDr(S, W, 12, 0x72be5d74);
RNDr(S, W, 13, 0x80deb1fe);
RNDr(S, W, 14, 0x9bdc06a7);
RNDr(S, W, 15, 0xc19bf174);
RNDr(S, W, 16, 0xe49b69c1);
RNDr(S, W, 17, 0xefbe4786);
RNDr(S, W, 18, 0x0fc19dc6);
RNDr(S, W, 19, 0x240ca1cc);
RNDr(S, W, 20, 0x2de92c6f);
RNDr(S, W, 21, 0x4a7484aa);
RNDr(S, W, 22, 0x5cb0a9dc);
RNDr(S, W, 23, 0x76f988da);
RNDr(S, W, 24, 0x983e5152);
RNDr(S, W, 25, 0xa831c66d);
RNDr(S, W, 26, 0xb00327c8);
RNDr(S, W, 27, 0xbf597fc7);
RNDr(S, W, 28, 0xc6e00bf3);
RNDr(S, W, 29, 0xd5a79147);
RNDr(S, W, 30, 0x06ca6351);
RNDr(S, W, 31, 0x14292967);
RNDr(S, W, 32, 0x27b70a85);
RNDr(S, W, 33, 0x2e1b2138);
RNDr(S, W, 34, 0x4d2c6dfc);
RNDr(S, W, 35, 0x53380d13);
RNDr(S, W, 36, 0x650a7354);
RNDr(S, W, 37, 0x766a0abb);
RNDr(S, W, 38, 0x81c2c92e);
RNDr(S, W, 39, 0x92722c85);
RNDr(S, W, 40, 0xa2bfe8a1);
RNDr(S, W, 41, 0xa81a664b);
RNDr(S, W, 42, 0xc24b8b70);
RNDr(S, W, 43, 0xc76c51a3);
RNDr(S, W, 44, 0xd192e819);
RNDr(S, W, 45, 0xd6990624);
RNDr(S, W, 46, 0xf40e3585);
RNDr(S, W, 47, 0x106aa070);
RNDr(S, W, 48, 0x19a4c116);
RNDr(S, W, 49, 0x1e376c08);
RNDr(S, W, 50, 0x2748774c);
RNDr(S, W, 51, 0x34b0bcb5);
RNDr(S, W, 52, 0x391c0cb3);
RNDr(S, W, 53, 0x4ed8aa4a);
RNDr(S, W, 54, 0x5b9cca4f);
RNDr(S, W, 55, 0x682e6ff3);
RNDr(S, W, 56, 0x748f82ee);
RNDr(S, W, 57, 0x78a5636f);
RNDr(S, W, 58, 0x84c87814);
RNDr(S, W, 59, 0x8cc70208);
RNDr(S, W, 60, 0x90befffa);
RNDr(S, W, 61, 0xa4506ceb);
RNDr(S, W, 62, 0xbef9a3f7);
RNDr(S, W, 63, 0xc67178f2);
/* 4. Mix local working variables into global state */
for (i = 0; i < 8; i++)
state[i] += S[i];
}
static unsigned char PAD[64] = {
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
/* Add padding and terminating bit-count. */
static void
SHA256_Pad(SHA256_CTX * ctx)
{
unsigned char len[8];
uint32_t r, plen;
/*
* Convert length to a vector of bytes -- we do this now rather
* than later because the length will change after we pad.
*/
be32enc_vect(len, ctx->count, 8);
/* Add 1--64 bytes so that the resulting length is 56 mod 64 */
r = (ctx->count[1] >> 3) & 0x3f;
plen = (r < 56) ? (56 - r) : (120 - r);
libscrypt_SHA256_Update(ctx, PAD, (size_t)plen);
/* Add the terminating bit-count */
libscrypt_SHA256_Update(ctx, len, 8);
}
/* SHA-256 initialization. Begins a SHA-256 operation. */
void
libscrypt_SHA256_Init(SHA256_CTX * ctx)
{
/* Zero bits processed so far */
ctx->count[0] = ctx->count[1] = 0;
/* Magic initialization constants */
ctx->state[0] = 0x6A09E667;
ctx->state[1] = 0xBB67AE85;
ctx->state[2] = 0x3C6EF372;
ctx->state[3] = 0xA54FF53A;
ctx->state[4] = 0x510E527F;
ctx->state[5] = 0x9B05688C;
ctx->state[6] = 0x1F83D9AB;
ctx->state[7] = 0x5BE0CD19;
}
/* Add bytes into the hash */
void
libscrypt_SHA256_Update(SHA256_CTX * ctx, const void *in, size_t len)
{
uint32_t bitlen[2];
uint32_t r;
const unsigned char *src = in;
/* Number of bytes left in the buffer from previous updates */
r = (ctx->count[1] >> 3) & 0x3f;
/* Convert the length into a number of bits */
bitlen[1] = ((uint32_t)len) << 3;
bitlen[0] = (uint32_t)(len >> 29);
/* Update number of bits */
if ((ctx->count[1] += bitlen[1]) < bitlen[1])
ctx->count[0]++;
ctx->count[0] += bitlen[0];
/* Handle the case where we don't need to perform any transforms */
if (len < 64 - r) {
memcpy(&ctx->buf[r], src, len);
return;
}
/* Finish the current block */
memcpy(&ctx->buf[r], src, 64 - r);
SHA256_Transform(ctx->state, ctx->buf);
src += 64 - r;
len -= 64 - r;
/* Perform complete blocks */
while (len >= 64) {
SHA256_Transform(ctx->state, src);
src += 64;
len -= 64;
}
/* Copy left over data into buffer */
memcpy(ctx->buf, src, len);
}
/*
* SHA-256 finalization. Pads the input data, exports the hash value,
* and clears the context state.
*/
void
libscrypt_SHA256_Final(unsigned char digest[32], SHA256_CTX * ctx)
{
/* Add padding */
SHA256_Pad(ctx);
/* Write the hash */
be32enc_vect(digest, ctx->state, 32);
/* Clear the context state */
memset((void *)ctx, 0, sizeof(*ctx));
}
/* Initialize an HMAC-SHA256 operation with the given key. */
void
libscrypt_HMAC_SHA256_Init(HMAC_SHA256_CTX * ctx, const void * _K, size_t Klen)
{
unsigned char pad[64];
unsigned char khash[32];
const unsigned char * K = _K;
size_t i;
/* If Klen > 64, the key is really SHA256(K). */
if (Klen > 64) {
libscrypt_SHA256_Init(&ctx->ictx);
libscrypt_SHA256_Update(&ctx->ictx, K, Klen);
libscrypt_SHA256_Final(khash, &ctx->ictx);
K = khash;
Klen = 32;
}
/* Inner SHA256 operation is SHA256(K xor [block of 0x36] || data). */
libscrypt_SHA256_Init(&ctx->ictx);
memset(pad, 0x36, 64);
for (i = 0; i < Klen; i++)
pad[i] ^= K[i];
libscrypt_SHA256_Update(&ctx->ictx, pad, 64);
/* Outer SHA256 operation is SHA256(K xor [block of 0x5c] || hash). */
libscrypt_SHA256_Init(&ctx->octx);
memset(pad, 0x5c, 64);
for (i = 0; i < Klen; i++)
pad[i] ^= K[i];
libscrypt_SHA256_Update(&ctx->octx, pad, 64);
}
/* Add bytes to the HMAC-SHA256 operation. */
void
libscrypt_HMAC_SHA256_Update(HMAC_SHA256_CTX * ctx, const void *in, size_t len)
{
/* Feed data to the inner SHA256 operation. */
libscrypt_SHA256_Update(&ctx->ictx, in, len);
}
/* Finish an HMAC-SHA256 operation. */
void
libscrypt_HMAC_SHA256_Final(unsigned char digest[32], HMAC_SHA256_CTX * ctx)
{
unsigned char ihash[32];
/* Finish the inner SHA256 operation. */
libscrypt_SHA256_Final(ihash, &ctx->ictx);
/* Feed the inner hash to the outer SHA256 operation. */
libscrypt_SHA256_Update(&ctx->octx, ihash, 32);
/* Finish the outer SHA256 operation. */
libscrypt_SHA256_Final(digest, &ctx->octx);
}
/**
* PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, c, buf, dkLen):
* Compute PBKDF2(passwd, salt, c, dkLen) using HMAC-SHA256 as the PRF, and
* write the output to buf. The value dkLen must be at most 32 * (2^32 - 1).
*/
void
libscrypt_PBKDF2_SHA256(const uint8_t * passwd, size_t passwdlen, const uint8_t * salt,
size_t saltlen, uint64_t c, uint8_t * buf, size_t dkLen)
{
HMAC_SHA256_CTX PShctx, hctx;
size_t i;
uint8_t ivec[4];
uint8_t U[32];
uint8_t T[32];
uint64_t j;
int k;
size_t clen;
/* Compute HMAC state after processing P and S. */
libscrypt_HMAC_SHA256_Init(&PShctx, passwd, passwdlen);
libscrypt_HMAC_SHA256_Update(&PShctx, salt, saltlen);
/* Iterate through the blocks. */
for (i = 0; i * 32 < dkLen; i++) {
/* Generate INT(i + 1). */
be32enc(ivec, (uint32_t)(i + 1));
/* Compute U_1 = PRF(P, S || INT(i)). */
memcpy(&hctx, &PShctx, sizeof(HMAC_SHA256_CTX));
libscrypt_HMAC_SHA256_Update(&hctx, ivec, 4);
libscrypt_HMAC_SHA256_Final(U, &hctx);
/* T_i = U_1 ... */
memcpy(T, U, 32);
for (j = 2; j <= c; j++) {
/* Compute U_j. */
libscrypt_HMAC_SHA256_Init(&hctx, passwd, passwdlen);
libscrypt_HMAC_SHA256_Update(&hctx, U, 32);
libscrypt_HMAC_SHA256_Final(U, &hctx);
/* ... xor U_j ... */
for (k = 0; k < 32; k++)
T[k] ^= U[k];
}
/* Copy as many bytes as necessary into buf. */
clen = dkLen - i * 32;
if (clen > 32)
clen = 32;
memcpy(&buf[i * 32], T, clen);
}
}
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