/*
 * SHA-512 hash implementation and interface functions
 * Copyright (c) 2015, Pali Rohár <pali.rohar@gmail.com>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"

#include "common.h"
#include "sha512_i.h"
#include "crypto.h"


/**
 * sha512_vector - SHA512 hash for data vector
 * @num_elem: Number of elements in the data vector
 * @addr: Pointers to the data areas
 * @len: Lengths of the data blocks
 * @mac: Buffer for the hash
 * Returns: 0 on success, -1 of failure
 */
int sha512_vector(size_t num_elem, const u8 *addr[], const size_t *len,
		  u8 *mac)
{
	struct sha512_state ctx;
	size_t i;

	sha512_init(&ctx);
	for (i = 0; i < num_elem; i++)
		if (sha512_process(&ctx, addr[i], len[i]))
			return -1;
	if (sha512_done(&ctx, mac))
		return -1;
	return 0;
}


/* ===== start - public domain SHA512 implementation ===== */

/* This is based on SHA512 implementation in LibTomCrypt that was released into
 * public domain by Tom St Denis. */

#define CONST64(n) n ## ULL

/* the K array */
static const u64 K[80] = {
	CONST64(0x428a2f98d728ae22), CONST64(0x7137449123ef65cd),
	CONST64(0xb5c0fbcfec4d3b2f), CONST64(0xe9b5dba58189dbbc),
	CONST64(0x3956c25bf348b538), CONST64(0x59f111f1b605d019),
	CONST64(0x923f82a4af194f9b), CONST64(0xab1c5ed5da6d8118),
	CONST64(0xd807aa98a3030242), CONST64(0x12835b0145706fbe),
	CONST64(0x243185be4ee4b28c), CONST64(0x550c7dc3d5ffb4e2),
	CONST64(0x72be5d74f27b896f), CONST64(0x80deb1fe3b1696b1),
	CONST64(0x9bdc06a725c71235), CONST64(0xc19bf174cf692694),
	CONST64(0xe49b69c19ef14ad2), CONST64(0xefbe4786384f25e3),
	CONST64(0x0fc19dc68b8cd5b5), CONST64(0x240ca1cc77ac9c65),
	CONST64(0x2de92c6f592b0275), CONST64(0x4a7484aa6ea6e483),
	CONST64(0x5cb0a9dcbd41fbd4), CONST64(0x76f988da831153b5),
	CONST64(0x983e5152ee66dfab), CONST64(0xa831c66d2db43210),
	CONST64(0xb00327c898fb213f), CONST64(0xbf597fc7beef0ee4),
	CONST64(0xc6e00bf33da88fc2), CONST64(0xd5a79147930aa725),
	CONST64(0x06ca6351e003826f), CONST64(0x142929670a0e6e70),
	CONST64(0x27b70a8546d22ffc), CONST64(0x2e1b21385c26c926),
	CONST64(0x4d2c6dfc5ac42aed), CONST64(0x53380d139d95b3df),
	CONST64(0x650a73548baf63de), CONST64(0x766a0abb3c77b2a8),
	CONST64(0x81c2c92e47edaee6), CONST64(0x92722c851482353b),
	CONST64(0xa2bfe8a14cf10364), CONST64(0xa81a664bbc423001),
	CONST64(0xc24b8b70d0f89791), CONST64(0xc76c51a30654be30),
	CONST64(0xd192e819d6ef5218), CONST64(0xd69906245565a910),
	CONST64(0xf40e35855771202a), CONST64(0x106aa07032bbd1b8),
	CONST64(0x19a4c116b8d2d0c8), CONST64(0x1e376c085141ab53),
	CONST64(0x2748774cdf8eeb99), CONST64(0x34b0bcb5e19b48a8),
	CONST64(0x391c0cb3c5c95a63), CONST64(0x4ed8aa4ae3418acb),
	CONST64(0x5b9cca4f7763e373), CONST64(0x682e6ff3d6b2b8a3),
	CONST64(0x748f82ee5defb2fc), CONST64(0x78a5636f43172f60),
	CONST64(0x84c87814a1f0ab72), CONST64(0x8cc702081a6439ec),
	CONST64(0x90befffa23631e28), CONST64(0xa4506cebde82bde9),
	CONST64(0xbef9a3f7b2c67915), CONST64(0xc67178f2e372532b),
	CONST64(0xca273eceea26619c), CONST64(0xd186b8c721c0c207),
	CONST64(0xeada7dd6cde0eb1e), CONST64(0xf57d4f7fee6ed178),
	CONST64(0x06f067aa72176fba), CONST64(0x0a637dc5a2c898a6),
	CONST64(0x113f9804bef90dae), CONST64(0x1b710b35131c471b),
	CONST64(0x28db77f523047d84), CONST64(0x32caab7b40c72493),
	CONST64(0x3c9ebe0a15c9bebc), CONST64(0x431d67c49c100d4c),
	CONST64(0x4cc5d4becb3e42b6), CONST64(0x597f299cfc657e2a),
	CONST64(0x5fcb6fab3ad6faec), CONST64(0x6c44198c4a475817)
};

/* Various logical functions */
#define Ch(x,y,z)       (z ^ (x & (y ^ z)))
#define Maj(x,y,z)      (((x | y) & z) | (x & y))
#define S(x, n)         ROR64c(x, n)
#define R(x, n)         (((x) & CONST64(0xFFFFFFFFFFFFFFFF)) >> ((u64) n))
#define Sigma0(x)       (S(x, 28) ^ S(x, 34) ^ S(x, 39))
#define Sigma1(x)       (S(x, 14) ^ S(x, 18) ^ S(x, 41))
#define Gamma0(x)       (S(x, 1) ^ S(x, 8) ^ R(x, 7))
#define Gamma1(x)       (S(x, 19) ^ S(x, 61) ^ R(x, 6))
#ifndef MIN
#define MIN(x, y) (((x) < (y)) ? (x) : (y))
#endif

#define ROR64c(x, y) \
    ( ((((x) & CONST64(0xFFFFFFFFFFFFFFFF)) >> ((u64) (y) & CONST64(63))) | \
      ((x) << ((u64) (64 - ((y) & CONST64(63)))))) & \
      CONST64(0xFFFFFFFFFFFFFFFF))

/* compress 1024-bits */
static int sha512_compress(struct sha512_state *md, unsigned char *buf)
{
	u64 S[8], W[80], t0, t1;
	int i;

	/* copy state into S */
	for (i = 0; i < 8; i++) {
		S[i] = md->state[i];
	}

	/* copy the state into 1024-bits into W[0..15] */
	for (i = 0; i < 16; i++)
		W[i] = WPA_GET_BE64(buf + (8 * i));

	/* fill W[16..79] */
	for (i = 16; i < 80; i++) {
		W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) +
			W[i - 16];
	}

	/* Compress */
	for (i = 0; i < 80; i++) {
		t0 = S[7] + Sigma1(S[4]) + Ch(S[4], S[5], S[6]) + K[i] + W[i];
		t1 = Sigma0(S[0]) + Maj(S[0], S[1], S[2]);
		S[7] = S[6];
		S[6] = S[5];
		S[5] = S[4];
		S[4] = S[3] + t0;
		S[3] = S[2];
		S[2] = S[1];
		S[1] = S[0];
		S[0] = t0 + t1;
	}

	/* feedback */
	for (i = 0; i < 8; i++) {
		md->state[i] = md->state[i] + S[i];
	}

	return 0;
}


/**
   Initialize the hash state
   @param md   The hash state you wish to initialize
   @return CRYPT_OK if successful
*/
void sha512_init(struct sha512_state *md)
{
	md->curlen = 0;
	md->length = 0;
	md->state[0] = CONST64(0x6a09e667f3bcc908);
	md->state[1] = CONST64(0xbb67ae8584caa73b);
	md->state[2] = CONST64(0x3c6ef372fe94f82b);
	md->state[3] = CONST64(0xa54ff53a5f1d36f1);
	md->state[4] = CONST64(0x510e527fade682d1);
	md->state[5] = CONST64(0x9b05688c2b3e6c1f);
	md->state[6] = CONST64(0x1f83d9abfb41bd6b);
	md->state[7] = CONST64(0x5be0cd19137e2179);
}


/**
   Process a block of memory though the hash
   @param md     The hash state
   @param in     The data to hash
   @param inlen  The length of the data (octets)
   @return CRYPT_OK if successful
*/
int sha512_process(struct sha512_state *md, const unsigned char *in,
		   unsigned long inlen)
{
	unsigned long n;

	if (md->curlen >= sizeof(md->buf))
		return -1;

	while (inlen > 0) {
		if (md->curlen == 0 && inlen >= SHA512_BLOCK_SIZE) {
			if (sha512_compress(md, (unsigned char *) in) < 0)
				return -1;
			md->length += SHA512_BLOCK_SIZE * 8;
			in += SHA512_BLOCK_SIZE;
			inlen -= SHA512_BLOCK_SIZE;
		} else {
			n = MIN(inlen, (SHA512_BLOCK_SIZE - md->curlen));
			os_memcpy(md->buf + md->curlen, in, n);
			md->curlen += n;
			in += n;
			inlen -= n;
			if (md->curlen == SHA512_BLOCK_SIZE) {
				if (sha512_compress(md, md->buf) < 0)
					return -1;
				md->length += 8 * SHA512_BLOCK_SIZE;
				md->curlen = 0;
			}
		}
	}

	return 0;
}


/**
   Terminate the hash to get the digest
   @param md  The hash state
   @param out [out] The destination of the hash (64 bytes)
   @return CRYPT_OK if successful
*/
int sha512_done(struct sha512_state *md, unsigned char *out)
{
	int i;

	if (md->curlen >= sizeof(md->buf))
		return -1;

	/* increase the length of the message */
	md->length += md->curlen * CONST64(8);

	/* append the '1' bit */
	md->buf[md->curlen++] = (unsigned char) 0x80;

	/* if the length is currently above 112 bytes we append zeros
	 * then compress.  Then we can fall back to padding zeros and length
	 * encoding like normal.
	 */
	if (md->curlen > 112) {
		while (md->curlen < 128) {
			md->buf[md->curlen++] = (unsigned char) 0;
		}
		sha512_compress(md, md->buf);
		md->curlen = 0;
	}

	/* pad up to 120 bytes of zeroes
	 * note: that from 112 to 120 is the 64 MSB of the length.  We assume
	 * that you won't hash > 2^64 bits of data... :-)
	 */
	while (md->curlen < 120) {
		md->buf[md->curlen++] = (unsigned char) 0;
	}

	/* store length */
	WPA_PUT_BE64(md->buf + 120, md->length);
	sha512_compress(md, md->buf);

	/* copy output */
	for (i = 0; i < 8; i++)
		WPA_PUT_BE64(out + (8 * i), md->state[i]);

	return 0;
}

/* ===== end - public domain SHA512 implementation ===== */