/*
 * Copyright (c) 2000-2001, Aaron D. Gifford
 * 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 copyright holder nor the names of contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTOR(S) ``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 CONTRIBUTOR(S) 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.
 *
 */

/******************************************************************************
 * Copyright (c) 2014, AllSeen Alliance. All rights reserved.
 *
 *    Permission to use, copy, modify, and/or distribute this software for any
 *    purpose with or without fee is hereby granted, provided that the above
 *    copyright notice and this permission notice appear in all copies.
 *
 *    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 ******************************************************************************/

//
// 4-MAY-2015; DICE adaptation (DennisMa;MSFT).
//
#include "stdint.h"
#include "string.h" // memcpy/memset
#include "DiceSha256.h"

/*** SHA-256 Machine Architecture Definitions *****************/
/*
 * BYTE_ORDER NOTE:
 *
 * Please make sure that your system defines BYTE_ORDER.  If your
 * architecture is little-endian, make sure it also defines
 * LITTLE_ENDIAN and that the two (BYTE_ORDER and LITTLE_ENDIAN) are
 * equivilent.
 *
 * If your system does not define the above, then you can do so by
 * hand like this:
 *
 *   #define LITTLE_ENDIAN 1234
 *   #define BIG_ENDIAN    4321
 *
 * And for little-endian machines, add:
 *
 *   #define BYTE_ORDER LITTLE_ENDIAN
 *
 * Or for big-endian machines:
 *
 *   #define BYTE_ORDER BIG_ENDIAN
 *
 * The FreeBSD machine this was written on defines BYTE_ORDER
 * appropriately by including <sys/types.h> (which in turn includes
 * <machine/endian.h> where the appropriate definitions are actually
 * made).
 */
#if !defined(BYTE_ORDER) || (BYTE_ORDER != LITTLE_ENDIAN && BYTE_ORDER != BIG_ENDIAN)
#define LITTLE_ENDIAN 1234
#define BIG_ENDIAN    4321
#if HOST_IS_LITTLE_ENDIAN
#define BYTE_ORDER LITTLE_ENDIAN
#else
#define BYTE_ORDER BIG_ENDIAN
#endif
#endif

/*
 * Define the followingsha2_* types to types of the correct length on
 * the native architecture.   Most BSD systems and Linux define u_intXX_t
 * types.  Machines with very recent ANSI C headers, can use the
 * uintXX_t definitions from inttypes.h by defining SHA2_USE_INTTYPES_H
 * during compile or in the sha.h header file.
 *
 * Machines that support neither u_intXX_t nor inttypes.h's uintXX_t
 * will need to define these three typedefs below (and the appropriate
 * ones in sha.h too) by hand according to their system architecture.
 *
 * Thank you, Jun-ichiro itojun Hagino, for suggesting using u_intXX_t
 * types and pointing out recent ANSI C support for uintXX_t in inttypes.h.
 */

/*** SHA-256 Length Definitions ***********************/
/* NOTE: Most of these are in sha2.h */
#define SHA256_SHORT_BLOCK_LENGTH   (SHA256_BLOCK_LENGTH - 8)

/*** ENDIAN REVERSAL MACROS *******************************************/
#if BYTE_ORDER == LITTLE_ENDIAN
#if !defined(ALIGNED_ACCESS_REQUIRED)
#define REVERSE32(w,x)  { \
    sha2_word32 tmp = (w); \
    tmp = (tmp >> 16) | (tmp << 16); \
    (x) = ((tmp & 0xff00ff00UL) >> 8) | ((tmp & 0x00ff00ffUL) << 8); \
}
#else
#define REVERSE32(w,x) { \
    sha2_uint8_t *b = (sha2_uint8_t*) &w; \
    sha2_word32 tmp = 0; \
    tmp = ((sha2_word32)*b++); \
    tmp = (tmp << 8) | ((sha2_word32)*b++); \
    tmp = (tmp << 8) | ((sha2_word32)*b++); \
    tmp = (tmp << 8) | ((sha2_word32)*b++); \
    (x) = tmp; \
}
#endif /* ALIGNED_ACCESS_REQUIRED */
#define REVERSE64(w,x)  { \
    sha2_word64 tmp = (w); \
    tmp = (tmp >> 32) | (tmp << 32); \
    tmp = ((tmp & 0xff00ff00ff00ff00ULL) >> 8) | \
          ((tmp & 0x00ff00ff00ff00ffULL) << 8); \
    (x) = ((tmp & 0xffff0000ffff0000ULL) >> 16) | \
          ((tmp & 0x0000ffff0000ffffULL) << 16); \
}
#endif /* BYTE_ORDER == LITTLE_ENDIAN */

/*
 * Macro for incrementally adding the unsigned 64-bit integer n to the
 * unsigned 128-bit integer (represented using a two-element array of
 * 64-bit words):
 */
#define ADDINC128(w,n)  { \
    (w)[0] += (sha2_word64)(n); \
    if ((w)[0] < (n)) { \
        (w)[1]++; \
    } \
}

/*
 * Macros for copying blocks of memory and for zeroing out ranges
 * of memory.  Using these macros makes it easy to switch from
 * using memset()/memcpy() and using bzero()/bcopy().
 *
 * Please define either SHA2_USE_MEMSET_MEMCPY or define
 * SHA2_USE_BZERO_BCOPY depending on which function set you
 * choose to use:
 */
#if !defined(SHA2_USE_MEMSET_MEMCPY) && !defined(SHA2_USE_BZERO_BCOPY)
/* Default to memset()/memcpy() if no option is specified */
#define SHA2_USE_MEMSET_MEMCPY  1
#endif
#if defined(SHA2_USE_MEMSET_MEMCPY) && defined(SHA2_USE_BZERO_BCOPY)
/* Abort with an error if BOTH options are defined */
#error Define either SHA2_USE_MEMSET_MEMCPY or SHA2_USE_BZERO_BCOPY, not both!
#endif

#ifdef SHA2_USE_MEMSET_MEMCPY
#define MEMSET_BZERO(p,l)   memset((p), 0, (l))
#define MEMCPY_BCOPY(d,s,l) memcpy((d), (s), (l))
#endif
#ifdef SHA2_USE_BZERO_BCOPY
#define MEMSET_BZERO(p,l)   bzero((p), (l))
#define MEMCPY_BCOPY(d,s,l) bcopy((s), (d), (l))
#endif


/*** THE SIX LOGICAL FUNCTIONS ****************************************/
/*
 * Bit shifting and rotation (used by the six SHA-XYZ logical functions:
 *
 *   NOTE:  The naming of R and S appears backwards here (R is a SHIFT and
 *   S is a ROTATION) because the SHA-256/384/512 description document
 *   (see http://csrc.nist.gov/cryptval/shs/sha256-384-512.pdf) uses this
 *   same "backwards" definition.
 */
/* Shift-right (used in SHA-256, SHA-384, and SHA-512): */
#define R(b,x)      ((x) >> (b))
/* 32-bit Rotate-right (used in SHA-256): */
#define S32(b,x)    (((x) >> (b)) | ((x) << (32 - (b))))

/* Two of six logical functions used in SHA-256, SHA-384, and SHA-512: */
#define Ch(x,y,z)   (((x) & (y)) ^ ((~(x)) & (z)))
#define Maj(x,y,z)  (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))

/* Four of six logical functions used in SHA-256: */
#define Sigma0_256(x)   (S32(2,  (x)) ^ S32(13, (x)) ^ S32(22, (x)))
#define Sigma1_256(x)   (S32(6,  (x)) ^ S32(11, (x)) ^ S32(25, (x)))
#define sigma0_256(x)   (S32(7,  (x)) ^ S32(18, (x)) ^ R(3 ,   (x)))
#define sigma1_256(x)   (S32(17, (x)) ^ S32(19, (x)) ^ R(10,   (x)))

/*** INTERNAL FUNCTION PROTOTYPES *************************************/
/* NOTE: These should not be accessed directly from outside this
 * library -- they are intended for private internal visibility/use
 * only.
 */
static void SHA256_Transform(DICE_SHA256_CONTEXT *, const sha2_word32 *);

/*** SHA-XYZ INITIAL HASH VALUES AND CONSTANTS ************************/
/* Hash constant words K for SHA-256: */
static const sha2_word32 K256[64] = {
    0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL,
    0x3956c25bUL, 0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL,
    0xd807aa98UL, 0x12835b01UL, 0x243185beUL, 0x550c7dc3UL,
    0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL, 0xc19bf174UL,
    0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
    0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL,
    0x983e5152UL, 0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL,
    0xc6e00bf3UL, 0xd5a79147UL, 0x06ca6351UL, 0x14292967UL,
    0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL, 0x53380d13UL,
    0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
    0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL,
    0xd192e819UL, 0xd6990624UL, 0xf40e3585UL, 0x106aa070UL,
    0x19a4c116UL, 0x1e376c08UL, 0x2748774cUL, 0x34b0bcb5UL,
    0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL, 0x682e6ff3UL,
    0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
    0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
};

/* Initial hash value H for SHA-256: */
static const sha2_word32 sha256_initial_hash_value[8] = {
    0x6a09e667UL,
    0xbb67ae85UL,
    0x3c6ef372UL,
    0xa54ff53aUL,
    0x510e527fUL,
    0x9b05688cUL,
    0x1f83d9abUL,
    0x5be0cd19UL
};

/*
 * Constant used by SHA256() functions for converting the
 * digest to a readable hexadecimal character string:
 */
//static const char *sha2_hex_digits = "0123456789abcdef";

/*** SHA-256: *********************************************************/
void DICE_SHA256_Init(DICE_SHA256_CONTEXT *context)
{
    if (context == (DICE_SHA256_CONTEXT *)0) {
        return;
    }
    context->magic = HASH_MAGIC_VALUE;
    MEMCPY_BCOPY(context->state, sha256_initial_hash_value, SHA256_DIGEST_LENGTH);
    MEMSET_BZERO(context->buffer, SHA256_BLOCK_LENGTH);
    context->bitcount = 0;
}

static void SHA256_Transform(DICE_SHA256_CONTEXT *context, const sha2_word32 *data)
{
    sha2_word32 a, b, c, d, e, f, g, h, s0, s1;
    sha2_word32 T1, T2, *W256;
    int     j;

    W256 = (sha2_word32 *)context->buffer;

    /* Initialize registers with the prev. intermediate value */
    a = context->state[0];
    b = context->state[1];
    c = context->state[2];
    d = context->state[3];
    e = context->state[4];
    f = context->state[5];
    g = context->state[6];
    h = context->state[7];

    j = 0;
    do {
#if BYTE_ORDER == LITTLE_ENDIAN
        /* Copy data while converting to host uint8_t order */
        REVERSE32(*data++,W256[j]);
        /* Apply the SHA-256 compression function to update a..h */
        T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] + W256[j];
#else /* BYTE_ORDER == LITTLE_ENDIAN */
        /* Apply the SHA-256 compression function to update a..h with copy */
        T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] + (W256[j] = *data++);
#endif /* BYTE_ORDER == LITTLE_ENDIAN */
        T2 = Sigma0_256(a) + Maj(a, b, c);
        h = g;
        g = f;
        f = e;
        e = d + T1;
        d = c;
        c = b;
        b = a;
        a = T1 + T2;

        j++;
    } while (j < 16);

    do {
        /* Part of the message block expansion: */
        s0 = W256[(j+1)&0x0f];
        s0 = sigma0_256(s0);
        s1 = W256[(j+14)&0x0f];
        s1 = sigma1_256(s1);

        /* Apply the SHA-256 compression function to update a..h */
        T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] +
             (W256[j&0x0f] += s1 + W256[(j+9)&0x0f] + s0);
        T2 = Sigma0_256(a) + Maj(a, b, c);
        h = g;
        g = f;
        f = e;
        e = d + T1;
        d = c;
        c = b;
        b = a;
        a = T1 + T2;

        j++;
    } while (j < 64);

    /* Compute the current intermediate hash value */
    context->state[0] += a;
    context->state[1] += b;
    context->state[2] += c;
    context->state[3] += d;
    context->state[4] += e;
    context->state[5] += f;
    context->state[6] += g;
    context->state[7] += h;

    /* Clean up */
    a = b = c = d = e = f = g = h = T1 = T2 = 0;
}

void DICE_SHA256_Update(DICE_SHA256_CONTEXT *context, const sha2_uint8_t *data, size_t len)
{
    unsigned int    freespace, usedspace;

    if (len == 0) {
        /* Calling with no data is valid - we do nothing */
        return;
    }

    usedspace = (context->bitcount >> 3) % SHA256_BLOCK_LENGTH;
    if (usedspace > 0) {
        /* Calculate how much free space is available in the buffer */
        freespace = SHA256_BLOCK_LENGTH - usedspace;

        if (len >= freespace) {
            /* Fill the buffer completely and process it */
            MEMCPY_BCOPY(&context->buffer[usedspace], data, freespace);
            context->bitcount += freespace << 3;
            len -= freespace;
            data += freespace;
            SHA256_Transform(context, (sha2_word32 *)context->buffer);
        } else {
            /* The buffer is not yet full */
            MEMCPY_BCOPY(&context->buffer[usedspace], data, len);
            context->bitcount += len << 3;
            /* Clean up: */
            usedspace = freespace = 0;
            return;
        }
    }
    while (len >= SHA256_BLOCK_LENGTH) {
        /* Process as many complete blocks as we can */
        SHA256_Transform(context, (sha2_word32 *)data);
        context->bitcount += SHA256_BLOCK_LENGTH << 3;
        len -= SHA256_BLOCK_LENGTH;
        data += SHA256_BLOCK_LENGTH;
    }
    if (len > 0) {
        /* There's left-overs, so save 'em */
        MEMCPY_BCOPY(context->buffer, data, len);
        context->bitcount += len << 3;
    }
    /* Clean up: */
    usedspace = freespace = 0;
}

void DICE_SHA256_Final(DICE_SHA256_CONTEXT *context, sha2_uint8_t *digest)
{
    sha2_word32 *d = (sha2_word32 *)digest;
    unsigned int    usedspace;

    /* If no digest buffer is passed, we don't bother doing this: */
    if (digest != (sha2_uint8_t *)0) {
        usedspace = (context->bitcount >> 3) % SHA256_BLOCK_LENGTH;
#if BYTE_ORDER == LITTLE_ENDIAN
        /* Convert FROM host uint8_t order */
        REVERSE64(context->bitcount,context->bitcount);
#endif
        if (usedspace > 0) {
            /* Begin padding with a 1 bit: */
            context->buffer[usedspace++] = 0x80;

            if (usedspace <= SHA256_SHORT_BLOCK_LENGTH) {
                /* Set-up for the last transform: */
                MEMSET_BZERO(&context->buffer[usedspace], SHA256_SHORT_BLOCK_LENGTH - usedspace);
            } else {
                if (usedspace < SHA256_BLOCK_LENGTH) {
                    MEMSET_BZERO(&context->buffer[usedspace], SHA256_BLOCK_LENGTH - usedspace);
                }
                /* Do second-to-last transform: */
                SHA256_Transform(context, (sha2_word32 *)context->buffer);

                /* And set-up for the last transform: */
                MEMSET_BZERO(context->buffer, SHA256_SHORT_BLOCK_LENGTH);
            }
        } else {
            /* Set-up for the last transform: */
            MEMSET_BZERO(context->buffer, SHA256_SHORT_BLOCK_LENGTH);

            /* Begin padding with a 1 bit: */
            *context->buffer = 0x80;
        }
        /* Set the bit count: */
        *(sha2_word64 *)&context->buffer[SHA256_SHORT_BLOCK_LENGTH] = context->bitcount;

        /* Final transform: */
        SHA256_Transform(context, (sha2_word32 *)context->buffer);

#if BYTE_ORDER == LITTLE_ENDIAN
        {
            /* Convert TO host uint8_t order */
            int j;
            for (j = 0; j < 8; j++) {
                REVERSE32(context->state[j],context->state[j]);
                *d++ = context->state[j];
            }
        }
#else
        MEMCPY_BCOPY(d, context->state, SHA256_DIGEST_LENGTH);
#endif
    }

    /* Clean up state data: */
    MEMSET_BZERO(context, sizeof(DICE_SHA256_CONTEXT));
    usedspace = 0;
}

void DiceSHA256Ctx(DICE_SHA256_CONTEXT *context, const uint8_t *buf, size_t bufSize, uint8_t *digest)
{
    DICE_SHA256_Init(context);
    DICE_SHA256_Update(context, buf, bufSize);
    DICE_SHA256_Final(context, digest);
}

void DiceSHA256(const uint8_t *buf, size_t bufSize, uint8_t *digest)
{
    DICE_SHA256_CONTEXT context;
    DICE_SHA256_Init(&context);
    DICE_SHA256_Update(&context, buf, bufSize);
    DICE_SHA256_Final(&context, digest);
}

void DiceSHA256_2(const uint8_t *buf1, size_t bufSize1, const uint8_t *buf2, size_t bufSize2, uint8_t *digest)
{
    DICE_SHA256_CONTEXT context;
    DICE_SHA256_Init(&context);
    DICE_SHA256_Update(&context, buf1, bufSize1);
    DICE_SHA256_Update(&context, buf2, bufSize2);
    DICE_SHA256_Final(&context, digest);
}