/*
   BLAKE2 reference source code package - reference C implementations
  
   Copyright 2012, Samuel Neves <sneves@dei.uc.pt>.  You may use this under the
   terms of the CC0, the OpenSSL Licence, or the Apache Public License 2.0, at
   your option.  The terms of these licenses can be found at:
  
   - CC0 1.0 Universal : http://creativecommons.org/publicdomain/zero/1.0
   - OpenSSL license   : https://www.openssl.org/source/license.html
   - Apache 2.0        : http://www.apache.org/licenses/LICENSE-2.0
  
   More information about the BLAKE2 hash function can be found at
   https://blake2.net.
*/

#include <stdint.h>
#include <string.h>
#include <stdio.h>

#include "blake2.h"
#include "blake2-impl.h"

static const uint64_t blake2b_IV[8] =
{
  0x6a09e667f3bcc908ULL, 0xbb67ae8584caa73bULL,
  0x3c6ef372fe94f82bULL, 0xa54ff53a5f1d36f1ULL,
  0x510e527fade682d1ULL, 0x9b05688c2b3e6c1fULL,
  0x1f83d9abfb41bd6bULL, 0x5be0cd19137e2179ULL
};

static const uint8_t blake2b_sigma[12][16] =
{
  {  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15 } ,
  { 14, 10,  4,  8,  9, 15, 13,  6,  1, 12,  0,  2, 11,  7,  5,  3 } ,
  { 11,  8, 12,  0,  5,  2, 15, 13, 10, 14,  3,  6,  7,  1,  9,  4 } ,
  {  7,  9,  3,  1, 13, 12, 11, 14,  2,  6,  5, 10,  4,  0, 15,  8 } ,
  {  9,  0,  5,  7,  2,  4, 10, 15, 14,  1, 11, 12,  6,  8,  3, 13 } ,
  {  2, 12,  6, 10,  0, 11,  8,  3,  4, 13,  7,  5, 15, 14,  1,  9 } ,
  { 12,  5,  1, 15, 14, 13,  4, 10,  0,  7,  6,  3,  9,  2,  8, 11 } ,
  { 13, 11,  7, 14, 12,  1,  3,  9,  5,  0, 15,  4,  8,  6,  2, 10 } ,
  {  6, 15, 14,  9, 11,  3,  0,  8, 12,  2, 13,  7,  1,  4, 10,  5 } ,
  { 10,  2,  8,  4,  7,  6,  1,  5, 15, 11,  9, 14,  3, 12, 13 , 0 } ,
  {  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15 } ,
  { 14, 10,  4,  8,  9, 15, 13,  6,  1, 12,  0,  2, 11,  7,  5,  3 }
};


BLAKE2_LOCAL_INLINE(int) blake2b_set_lastnode( blake2b_state *S )
{
  S->f[1] = -1;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_clear_lastnode( blake2b_state *S )
{
  S->f[1] = 0;
  return 0;
}

/* Some helper functions, not necessarily useful */
BLAKE2_LOCAL_INLINE(int) blake2b_is_lastblock( const blake2b_state *S )
{
  return S->f[0] != 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_set_lastblock( blake2b_state *S )
{
  if( S->last_node ) blake2b_set_lastnode( S );

  S->f[0] = -1;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_clear_lastblock( blake2b_state *S )
{
  if( S->last_node ) blake2b_clear_lastnode( S );

  S->f[0] = 0;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_increment_counter( blake2b_state *S, const uint64_t inc )
{
  S->t[0] += inc;
  S->t[1] += ( S->t[0] < inc );
  return 0;
}



/* Parameter-related functions */
BLAKE2_LOCAL_INLINE(int) blake2b_param_set_digest_length( blake2b_param *P, const uint8_t digest_length )
{
  P->digest_length = digest_length;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_param_set_fanout( blake2b_param *P, const uint8_t fanout )
{
  P->fanout = fanout;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_param_set_max_depth( blake2b_param *P, const uint8_t depth )
{
  P->depth = depth;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_param_set_leaf_length( blake2b_param *P, const uint32_t leaf_length )
{
  store32( &P->leaf_length, leaf_length );
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_param_set_node_offset( blake2b_param *P, const uint64_t node_offset )
{
  store64( &P->node_offset, node_offset );
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_param_set_node_depth( blake2b_param *P, const uint8_t node_depth )
{
  P->node_depth = node_depth;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_param_set_inner_length( blake2b_param *P, const uint8_t inner_length )
{
  P->inner_length = inner_length;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_param_set_salt( blake2b_param *P, const uint8_t salt[BLAKE2B_SALTBYTES] )
{
  memcpy( P->salt, salt, BLAKE2B_SALTBYTES );
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_param_set_personal( blake2b_param *P, const uint8_t personal[BLAKE2B_PERSONALBYTES] )
{
  memcpy( P->personal, personal, BLAKE2B_PERSONALBYTES );
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2b_init0( blake2b_state *S )
{
  memset( S, 0, sizeof( blake2b_state ) );

  for( int i = 0; i < 8; ++i ) S->h[i] = blake2b_IV[i];

  return 0;
}

/* init xors IV with input parameter block */
int blake2b_init_param( blake2b_state *S, const blake2b_param *P )
{
  const uint8_t *p = ( const uint8_t * )( P );

  blake2b_init0( S );

  /* IV XOR ParamBlock */
  for( size_t i = 0; i < 8; ++i )
    S->h[i] ^= load64( p + sizeof( S->h[i] ) * i );

  return 0;
}



int blake2b_init( blake2b_state *S, const uint8_t outlen )
{
  blake2b_param P[1];

  if ( ( !outlen ) || ( outlen > BLAKE2B_OUTBYTES ) ) return -1;

  P->digest_length = outlen;
  P->key_length    = 0;
  P->fanout        = 1;
  P->depth         = 1;
  store32( &P->leaf_length, 0 );
  store64( &P->node_offset, 0 );
  P->node_depth    = 0;
  P->inner_length  = 0;
  memset( P->reserved, 0, sizeof( P->reserved ) );
  memset( P->salt,     0, sizeof( P->salt ) );
  memset( P->personal, 0, sizeof( P->personal ) );
  return blake2b_init_param( S, P );
}


int blake2b_init_key( blake2b_state *S, const uint8_t outlen, const void *key, const uint8_t keylen )
{
  blake2b_param P[1];

  if ( ( !outlen ) || ( outlen > BLAKE2B_OUTBYTES ) ) return -1;

  if ( !key || !keylen || keylen > BLAKE2B_KEYBYTES ) return -1;

  P->digest_length = outlen;
  P->key_length    = keylen;
  P->fanout        = 1;
  P->depth         = 1;
  store32( &P->leaf_length, 0 );
  store64( &P->node_offset, 0 );
  P->node_depth    = 0;
  P->inner_length  = 0;
  memset( P->reserved, 0, sizeof( P->reserved ) );
  memset( P->salt,     0, sizeof( P->salt ) );
  memset( P->personal, 0, sizeof( P->personal ) );

  if( blake2b_init_param( S, P ) < 0 ) return -1;

  {
    uint8_t block[BLAKE2B_BLOCKBYTES];
    memset( block, 0, BLAKE2B_BLOCKBYTES );
    memcpy( block, key, keylen );
    blake2b_update( S, block, BLAKE2B_BLOCKBYTES );
    secure_zero_memory( block, BLAKE2B_BLOCKBYTES ); /* Burn the key from stack */
  }
  return 0;
}

static int blake2b_compress( blake2b_state *S, const uint8_t block[BLAKE2B_BLOCKBYTES] )
{
  uint64_t m[16];
  uint64_t v[16];
  int i;

  for( i = 0; i < 16; ++i )
    m[i] = load64( block + i * sizeof( m[i] ) );

  for( i = 0; i < 8; ++i )
    v[i] = S->h[i];

  v[ 8] = blake2b_IV[0];
  v[ 9] = blake2b_IV[1];
  v[10] = blake2b_IV[2];
  v[11] = blake2b_IV[3];
  v[12] = S->t[0] ^ blake2b_IV[4];
  v[13] = S->t[1] ^ blake2b_IV[5];
  v[14] = S->f[0] ^ blake2b_IV[6];
  v[15] = S->f[1] ^ blake2b_IV[7];
#define G(r,i,a,b,c,d) \
  do { \
    a = a + b + m[blake2b_sigma[r][2*i+0]]; \
    d = rotr64(d ^ a, 32); \
    c = c + d; \
    b = rotr64(b ^ c, 24); \
    a = a + b + m[blake2b_sigma[r][2*i+1]]; \
    d = rotr64(d ^ a, 16); \
    c = c + d; \
    b = rotr64(b ^ c, 63); \
  } while(0)
#define ROUND(r)  \
  do { \
    G(r,0,v[ 0],v[ 4],v[ 8],v[12]); \
    G(r,1,v[ 1],v[ 5],v[ 9],v[13]); \
    G(r,2,v[ 2],v[ 6],v[10],v[14]); \
    G(r,3,v[ 3],v[ 7],v[11],v[15]); \
    G(r,4,v[ 0],v[ 5],v[10],v[15]); \
    G(r,5,v[ 1],v[ 6],v[11],v[12]); \
    G(r,6,v[ 2],v[ 7],v[ 8],v[13]); \
    G(r,7,v[ 3],v[ 4],v[ 9],v[14]); \
  } while(0)
  ROUND( 0 );
  ROUND( 1 );
  ROUND( 2 );
  ROUND( 3 );
  ROUND( 4 );
  ROUND( 5 );
  ROUND( 6 );
  ROUND( 7 );
  ROUND( 8 );
  ROUND( 9 );
  ROUND( 10 );
  ROUND( 11 );

  for( i = 0; i < 8; ++i )
    S->h[i] = S->h[i] ^ v[i] ^ v[i + 8];

#undef G
#undef ROUND
  return 0;
}

/* inlen now in bytes */
int blake2b_update( blake2b_state *S, const uint8_t *in, uint64_t inlen )
{
  while( inlen > 0 )
  {
    size_t left = S->buflen;
    size_t fill = 2 * BLAKE2B_BLOCKBYTES - left;

    if( inlen > fill )
    {
      memcpy( S->buf + left, in, fill ); /* Fill buffer */
      S->buflen += fill;
      blake2b_increment_counter( S, BLAKE2B_BLOCKBYTES );
      blake2b_compress( S, S->buf ); /* Compress */
      memcpy( S->buf, S->buf + BLAKE2B_BLOCKBYTES, BLAKE2B_BLOCKBYTES ); /* Shift buffer left */
      S->buflen -= BLAKE2B_BLOCKBYTES;
      in += fill;
      inlen -= fill;
    }
    else /* inlen <= fill */
    {
      memcpy( S->buf + left, in, inlen );
      S->buflen += inlen; /* Be lazy, do not compress */
      in += inlen;
      inlen -= inlen;
    }
  }

  return 0;
}

/* Is this correct? */
int blake2b_final( blake2b_state *S, uint8_t *out, uint8_t outlen )
{
  uint8_t buffer[BLAKE2B_OUTBYTES] = {0};

  if( out == NULL || outlen == 0 || outlen > BLAKE2B_OUTBYTES )
    return -1;

  if( blake2b_is_lastblock( S ) )
    return -1;

  if( S->buflen > BLAKE2B_BLOCKBYTES )
  {
    blake2b_increment_counter( S, BLAKE2B_BLOCKBYTES );
    blake2b_compress( S, S->buf );
    S->buflen -= BLAKE2B_BLOCKBYTES;
    memcpy( S->buf, S->buf + BLAKE2B_BLOCKBYTES, S->buflen );
  }

  blake2b_increment_counter( S, S->buflen );
  blake2b_set_lastblock( S );
  memset( S->buf + S->buflen, 0, 2 * BLAKE2B_BLOCKBYTES - S->buflen ); /* Padding */
  blake2b_compress( S, S->buf );

  for( int i = 0; i < 8; ++i ) /* Output full hash to temp buffer */
    store64( buffer + sizeof( S->h[i] ) * i, S->h[i] );

  memcpy( out, buffer, outlen );
  return 0;
}

/* inlen, at least, should be uint64_t. Others can be size_t. */
int blake2b( uint8_t *out, const void *in, const void *key, const uint8_t outlen, const uint64_t inlen, uint8_t keylen )
{
  blake2b_state S[1];

  /* Verify parameters */
  if ( NULL == in && inlen > 0 ) return -1;

  if ( NULL == out ) return -1;

  if( NULL == key && keylen > 0 ) return -1;

  if( !outlen || outlen > BLAKE2B_OUTBYTES ) return -1;

  if( keylen > BLAKE2B_KEYBYTES ) return -1;

  if( keylen > 0 )
  {
    if( blake2b_init_key( S, outlen, key, keylen ) < 0 ) return -1;
  }
  else
  {
    if( blake2b_init( S, outlen ) < 0 ) return -1;
  }

  blake2b_update( S, ( const uint8_t * )in, inlen );
  blake2b_final( S, out, outlen );
  return 0;
}

#if defined(SUPERCOP)
int crypto_hash( unsigned char *out, unsigned char *in, unsigned long long inlen )
{
  return blake2b( out, in, NULL, BLAKE2B_OUTBYTES, inlen, 0 );
}
#endif

#if defined(BLAKE2B_SELFTEST)
#include <string.h>
#include "blake2-kat.h"
int main( int argc, char **argv )
{
  uint8_t key[BLAKE2B_KEYBYTES];
  uint8_t buf[KAT_LENGTH];

  for( size_t i = 0; i < BLAKE2B_KEYBYTES; ++i )
    key[i] = ( uint8_t )i;

  for( size_t i = 0; i < KAT_LENGTH; ++i )
    buf[i] = ( uint8_t )i;

  for( size_t i = 0; i < KAT_LENGTH; ++i )
  {
    uint8_t hash[BLAKE2B_OUTBYTES];
    blake2b( hash, buf, key, BLAKE2B_OUTBYTES, i, BLAKE2B_KEYBYTES );

    if( 0 != memcmp( hash, blake2b_keyed_kat[i], BLAKE2B_OUTBYTES ) )
    {
      puts( "error" );
      return -1;
    }
  }

  puts( "ok" );
  return 0;
}
#endif