ta/crypt/sha2_impl.c

/*
 * Copyright (c) 2014, STMicroelectronics International N.V.
 * 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
 */

/*
 * FIPS 180-2 SHA-224/256/384/512 implementation
 * Last update: 02/02/2007
 * Issue date:  04/30/2005
 *
 * Copyright (C) 2005, 2007 Olivier Gay <olivier.gay@a3.epfl.ch>
 * 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.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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 <stddef.h>
#include <stdint.h>
#include <tee_api.h>

#include "sha2_impl.h"

#define SHFR(x, n)    (x >> n)
#define ROTR(x, n)   ((x >> n) | (x << ((sizeof(x) << 3) - n)))
#define ROTL(x, n)   ((x << n) | (x >> ((sizeof(x) << 3) - n)))
#define CH(x, y, z)  ((x & y) ^ (~x & z))
#define MAJ(x, y, z) ((x & y) ^ (x & z) ^ (y & z))

#define SHA256_F1(x) (ROTR(x,  2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define SHA256_F2(x) (ROTR(x,  6) ^ ROTR(x, 11) ^ ROTR(x, 25))
#define SHA256_F3(x) (ROTR(x,  7) ^ ROTR(x, 18) ^ SHFR(x,  3))
#define SHA256_F4(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHFR(x, 10))

#define UNPACK32(x, str)                              \
	{                                             \
		*((str) + 3) = (uint8_t) ((x));       \
		*((str) + 2) = (uint8_t) ((x) >>  8); \
		*((str) + 1) = (uint8_t) ((x) >> 16); \
		*((str) + 0) = (uint8_t) ((x) >> 24); \
	}

#define PACK32(str, x)                              \
	{                                           \
	*(x) =   ((uint32_t) *((str) + 3))         \
		| ((uint32_t) *((str) + 2) <<  8)  \
		| ((uint32_t) *((str) + 1) << 16)  \
		| ((uint32_t) *((str) + 0) << 24); \
	}

/* Macros used for loops unrolling */
#define SHA256_SCR(i)                               \
{                                                   \
	w[i] =  SHA256_F4(w[i -  2]) + w[i -  7]    \
		+ SHA256_F3(w[i - 15]) + w[i - 16]; \
}

#define SHA256_EXP(a, b, c, d, e, f, g, h, j)                   \
{                                                               \
	t1 = wv[h] + SHA256_F2(wv[e]) + CH(wv[e], wv[f], wv[g]) \
		+ sha256_k[j] + w[j];                           \
	t2 = SHA256_F1(wv[a]) + MAJ(wv[a], wv[b], wv[c]);       \
	wv[d] += t1;                                            \
	wv[h] = t1 + t2;                                        \
}

uint32_t sha224_h0[8] = {
	0xc1059ed8, 0x367cd507, 0x3070dd17, 0xf70e5939,
	0xffc00b31, 0x68581511, 0x64f98fa7, 0xbefa4fa4
};

uint32_t sha256_h0[8] = {
	0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
	0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
};

uint32_t sha256_k[64] = {
	0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
	0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
	0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
	0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
	0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
	0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
	0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
	0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
	0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
	0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
	0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
	0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
	0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
	0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
	0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
	0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};

/* SHA-256 functions */
void sha256_transf(struct sha256_ctx *ctx, const unsigned char *message,
		   unsigned int block_nb)
{
	uint32_t w[64] = { };
	uint32_t wv[8] = { };
	uint32_t t1 = 0;
	uint32_t t2 = 0;
	const unsigned char *sub_block = NULL;
	int i = 0;
#ifndef UNROLL_LOOPS
	int j = 0;
#endif

	for (i = 0; i < (int)block_nb; i++) {
		sub_block = message + (i << 6);

#ifndef UNROLL_LOOPS
		for (j = 0; j < 16; j++)
			PACK32(&sub_block[j << 2], &w[j]);

		for (j = 16; j < 64; j++)
			SHA256_SCR(j);

		for (j = 0; j < 8; j++)
			wv[j] = ctx->h[j];

		for (j = 0; j < 64; j++) {
			t1 = wv[7] + SHA256_F2(wv[4]) + CH(wv[4], wv[5], wv[6])
			    + sha256_k[j] + w[j];
			t2 = SHA256_F1(wv[0]) + MAJ(wv[0], wv[1], wv[2]);
			wv[7] = wv[6];
			wv[6] = wv[5];
			wv[5] = wv[4];
			wv[4] = wv[3] + t1;
			wv[3] = wv[2];
			wv[2] = wv[1];
			wv[1] = wv[0];
			wv[0] = t1 + t2;
		}

		for (j = 0; j < 8; j++)
			ctx->h[j] += wv[j];
#else
		PACK32(&sub_block[0], &w[0]);
		PACK32(&sub_block[4], &w[1]);
		PACK32(&sub_block[8], &w[2]);
		PACK32(&sub_block[12], &w[3]);
		PACK32(&sub_block[16], &w[4]);
		PACK32(&sub_block[20], &w[5]);
		PACK32(&sub_block[24], &w[6]);
		PACK32(&sub_block[28], &w[7]);
		PACK32(&sub_block[32], &w[8]);
		PACK32(&sub_block[36], &w[9]);
		PACK32(&sub_block[40], &w[10]);
		PACK32(&sub_block[44], &w[11]);
		PACK32(&sub_block[48], &w[12]);
		PACK32(&sub_block[52], &w[13]);
		PACK32(&sub_block[56], &w[14]);
		PACK32(&sub_block[60], &w[15]);

		SHA256_SCR(16);
		SHA256_SCR(17);
		SHA256_SCR(18);
		SHA256_SCR(19);
		SHA256_SCR(20);
		SHA256_SCR(21);
		SHA256_SCR(22);
		SHA256_SCR(23);
		SHA256_SCR(24);
		SHA256_SCR(25);
		SHA256_SCR(26);
		SHA256_SCR(27);
		SHA256_SCR(28);
		SHA256_SCR(29);
		SHA256_SCR(30);
		SHA256_SCR(31);
		SHA256_SCR(32);
		SHA256_SCR(33);
		SHA256_SCR(34);
		SHA256_SCR(35);
		SHA256_SCR(36);
		SHA256_SCR(37);
		SHA256_SCR(38);
		SHA256_SCR(39);
		SHA256_SCR(40);
		SHA256_SCR(41);
		SHA256_SCR(42);
		SHA256_SCR(43);
		SHA256_SCR(44);
		SHA256_SCR(45);
		SHA256_SCR(46);
		SHA256_SCR(47);
		SHA256_SCR(48);
		SHA256_SCR(49);
		SHA256_SCR(50);
		SHA256_SCR(51);
		SHA256_SCR(52);
		SHA256_SCR(53);
		SHA256_SCR(54);
		SHA256_SCR(55);
		SHA256_SCR(56);
		SHA256_SCR(57);
		SHA256_SCR(58);
		SHA256_SCR(59);
		SHA256_SCR(60);
		SHA256_SCR(61);
		SHA256_SCR(62);
		SHA256_SCR(63);

		wv[0] = ctx->h[0];
		wv[1] = ctx->h[1];
		wv[2] = ctx->h[2];
		wv[3] = ctx->h[3];
		wv[4] = ctx->h[4];
		wv[5] = ctx->h[5];
		wv[6] = ctx->h[6];
		wv[7] = ctx->h[7];

		SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 0);
		SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 1);
		SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 2);
		SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 3);
		SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 4);
		SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 5);
		SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 6);
		SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 7);
		SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 8);
		SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 9);
		SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 10);
		SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 11);
		SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 12);
		SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 13);
		SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 14);
		SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 15);
		SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 16);
		SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 17);
		SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 18);
		SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 19);
		SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 20);
		SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 21);
		SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 22);
		SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 23);
		SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 24);
		SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 25);
		SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 26);
		SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 27);
		SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 28);
		SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 29);
		SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 30);
		SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 31);
		SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 32);
		SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 33);
		SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 34);
		SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 35);
		SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 36);
		SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 37);
		SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 38);
		SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 39);
		SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 40);
		SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 41);
		SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 42);
		SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 43);
		SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 44);
		SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 45);
		SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 46);
		SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 47);
		SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 48);
		SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 49);
		SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 50);
		SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 51);
		SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 52);
		SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 53);
		SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 54);
		SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 55);
		SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 56);
		SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 57);
		SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 58);
		SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 59);
		SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 60);
		SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 61);
		SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 62);
		SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 63);

		ctx->h[0] += wv[0];
		ctx->h[1] += wv[1];
		ctx->h[2] += wv[2];
		ctx->h[3] += wv[3];
		ctx->h[4] += wv[4];
		ctx->h[5] += wv[5];
		ctx->h[6] += wv[6];
		ctx->h[7] += wv[7];
#endif
	}
}

void sha256(const unsigned char *message,
	    unsigned int len, unsigned char *digest)
{
	struct sha256_ctx ctx = { };

	sha256_init(&ctx);
	sha256_update(&ctx, message, len);
	sha256_final(&ctx, digest);
}

void sha256_init(struct sha256_ctx *ctx)
{
#ifndef UNROLL_LOOPS
	int i = 0;

	for (i = 0; i < 8; i++)
		ctx->h[i] = sha256_h0[i];
#else
	ctx->h[0] = sha256_h0[0];
	ctx->h[1] = sha256_h0[1];
	ctx->h[2] = sha256_h0[2];
	ctx->h[3] = sha256_h0[3];
	ctx->h[4] = sha256_h0[4];
	ctx->h[5] = sha256_h0[5];
	ctx->h[6] = sha256_h0[6];
	ctx->h[7] = sha256_h0[7];
#endif

	ctx->len = 0;
	ctx->tot_len = 0;
}

void sha256_update(struct sha256_ctx *ctx, const unsigned char *message,
		   unsigned int len)
{
	unsigned int block_nb = 0;
	unsigned int new_len = 0;
	unsigned int rem_len = 0;
	unsigned int tmp_len = 0;
	const unsigned char *shifted_message = NULL;
	unsigned long int i = 0;

	tmp_len = SHA256_BLOCK_SIZE - ctx->len;
	rem_len = len < tmp_len ? len : tmp_len;

	for (i = 0; i < rem_len; i++)
		ctx->block[ctx->len + i] = message[i];

	if (ctx->len + len < SHA256_BLOCK_SIZE) {
		ctx->len += len;
		return;
	}

	new_len = len - rem_len;
	block_nb = new_len / SHA256_BLOCK_SIZE;

	shifted_message = message + rem_len;

	sha256_transf(ctx, ctx->block, 1);
	sha256_transf(ctx, shifted_message, block_nb);

	rem_len = new_len % SHA256_BLOCK_SIZE;

	for (i = 0; i < rem_len; i++)
		ctx->block[i] = shifted_message[(block_nb << 6) + i];

	ctx->len = rem_len;
	ctx->tot_len += (block_nb + 1) << 6;
}

void sha256_final(struct sha256_ctx *ctx, unsigned char *digest)
{
	unsigned int block_nb = 0;
	unsigned int pm_len = 0;
	unsigned int len_b = 0;
	unsigned long int i_m = 0;
#ifndef UNROLL_LOOPS
	int i = 0;
#endif

	block_nb = 1;
	if ((SHA256_BLOCK_SIZE - 9) < (ctx->len % SHA256_BLOCK_SIZE))
		block_nb++;

	len_b = (ctx->tot_len + ctx->len) << 3;
	pm_len = block_nb << 6;

	for (i_m = 0; i_m < pm_len - ctx->len; i_m++)
		ctx->block[ctx->len + i_m] = 0;

	ctx->block[ctx->len] = 0x80;
	UNPACK32(len_b, ctx->block + pm_len - 4);

	sha256_transf(ctx, ctx->block, block_nb);

#ifndef UNROLL_LOOPS
	for (i = 0; i < 8; i++)
		UNPACK32(ctx->h[i], &digest[i << 2]);
#else
	UNPACK32(ctx->h[0], &digest[0]);
	UNPACK32(ctx->h[1], &digest[4]);
	UNPACK32(ctx->h[2], &digest[8]);
	UNPACK32(ctx->h[3], &digest[12]);
	UNPACK32(ctx->h[4], &digest[16]);
	UNPACK32(ctx->h[5], &digest[20]);
	UNPACK32(ctx->h[6], &digest[24]);
	UNPACK32(ctx->h[7], &digest[28]);
#endif
}

/* SHA-224 functions */
void sha224(const unsigned char *message, unsigned int len,
	    unsigned char *digest)
{
	struct sha224_ctx ctx = { };

	sha224_init(&ctx);
	sha224_update(&ctx, message, len);
	sha224_final(&ctx, digest);
}

void sha224_init(struct sha224_ctx *ctx)
{
#ifndef UNROLL_LOOPS
	int i = 0;

	for (i = 0; i < 8; i++)
		ctx->h[i] = sha224_h0[i];
#else
	ctx->h[0] = sha224_h0[0];
	ctx->h[1] = sha224_h0[1];
	ctx->h[2] = sha224_h0[2];
	ctx->h[3] = sha224_h0[3];
	ctx->h[4] = sha224_h0[4];
	ctx->h[5] = sha224_h0[5];
	ctx->h[6] = sha224_h0[6];
	ctx->h[7] = sha224_h0[7];
#endif

	ctx->len = 0;
	ctx->tot_len = 0;
}

void sha224_update(struct sha224_ctx *ctx, const unsigned char *message,
		   unsigned int len)
{
	unsigned int block_nb = 0;
	unsigned int new_len = 0;
	unsigned int rem_len = 0;
	unsigned int tmp_len = 0;
	const unsigned char *shifted_message = NULL;
	unsigned long int i = 0;

	tmp_len = SHA224_BLOCK_SIZE - ctx->len;
	rem_len = len < tmp_len ? len : tmp_len;

	for (i = 0; i < rem_len; i++)
		ctx->block[ctx->len + i] = message[i];

	if (ctx->len + len < SHA224_BLOCK_SIZE) {
		ctx->len += len;
		return;
	}

	new_len = len - rem_len;
	block_nb = new_len / SHA224_BLOCK_SIZE;

	shifted_message = message + rem_len;

	sha256_transf((struct sha256_ctx *)ctx, ctx->block, 1);
	sha256_transf((struct sha256_ctx *)ctx, shifted_message, block_nb);

	rem_len = new_len % SHA224_BLOCK_SIZE;

	for (i = 0; i < rem_len; i++)
		ctx->block[i] = shifted_message[(block_nb << 6) + i];

	ctx->len = rem_len;
	ctx->tot_len += (block_nb + 1) << 6;
}

void sha224_final(struct sha224_ctx *ctx, unsigned char *digest)
{
	unsigned int block_nb = 0;
	unsigned int pm_len = 0;
	unsigned int len_b = 0;
	unsigned long int i_m = 0;
#ifndef UNROLL_LOOPS
	int i = 0;
#endif

	block_nb = 1;
	if ((SHA224_BLOCK_SIZE - 9) < (ctx->len % SHA224_BLOCK_SIZE))
		block_nb++;

	len_b = (ctx->tot_len + ctx->len) << 3;
	pm_len = block_nb << 6;

	for (i_m = 0; i_m < pm_len - ctx->len; i_m++)
		ctx->block[ctx->len + i_m] = 0;

	ctx->block[ctx->len] = 0x80;
	UNPACK32(len_b, ctx->block + pm_len - 4);

	sha256_transf((struct sha256_ctx *)ctx, ctx->block, block_nb);

#ifndef UNROLL_LOOPS
	for (i = 0; i < 7; i++)
		UNPACK32(ctx->h[i], &digest[i << 2]);
#else
	UNPACK32(ctx->h[0], &digest[0]);
	UNPACK32(ctx->h[1], &digest[4]);
	UNPACK32(ctx->h[2], &digest[8]);
	UNPACK32(ctx->h[3], &digest[12]);
	UNPACK32(ctx->h[4], &digest[16]);
	UNPACK32(ctx->h[5], &digest[20]);
	UNPACK32(ctx->h[6], &digest[24]);
#endif
}