// SPDX-License-Identifier: (GPL-2.0-only OR Apache-2.0)
  /*
   * BLAKE2b 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.
   *
   * Note: the original sources have been modified for inclusion in linux kernel
   * in terms of coding style, using generic helpers and simplifications of error
   * handling.
   */
  
  #include <asm/unaligned.h>
  #include <linux/module.h>
  #include <linux/string.h>
  #include <linux/kernel.h>
  #include <linux/bitops.h>
  #include <crypto/internal/hash.h>
  
  #define BLAKE2B_160_DIGEST_SIZE		(160 / 8)
  #define BLAKE2B_256_DIGEST_SIZE		(256 / 8)
  #define BLAKE2B_384_DIGEST_SIZE		(384 / 8)
  #define BLAKE2B_512_DIGEST_SIZE		(512 / 8)
  
  enum blake2b_constant {
  	BLAKE2B_BLOCKBYTES    = 128,

  	BLAKE2B_KEYBYTES      = 64,

  };
  
  struct blake2b_state {
  	u64      h[8];
  	u64      t[2];
  	u64      f[2];
  	u8       buf[BLAKE2B_BLOCKBYTES];
  	size_t   buflen;

  };

  static const u64 blake2b_IV[8] = {
  	0x6a09e667f3bcc908ULL, 0xbb67ae8584caa73bULL,
  	0x3c6ef372fe94f82bULL, 0xa54ff53a5f1d36f1ULL,
  	0x510e527fade682d1ULL, 0x9b05688c2b3e6c1fULL,
  	0x1f83d9abfb41bd6bULL, 0x5be0cd19137e2179ULL
  };
  
  static const u8 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 }
  };

  static void blake2b_increment_counter(struct blake2b_state *S, const u64 inc)
  {
  	S->t[0] += inc;
  	S->t[1] += (S->t[0] < inc);
  }

  #define G(r,i,a,b,c,d)                                  \
  	do {                                            \
  		a = a + b + m[blake2b_sigma[r][2*i+0]]; \
  		d = ror64(d ^ a, 32);                   \
  		c = c + d;                              \
  		b = ror64(b ^ c, 24);                   \
  		a = a + b + m[blake2b_sigma[r][2*i+1]]; \
  		d = ror64(d ^ a, 16);                   \
  		c = c + d;                              \
  		b = ror64(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)
  
  static void blake2b_compress(struct blake2b_state *S,
  			     const u8 block[BLAKE2B_BLOCKBYTES])
  {
  	u64 m[16];
  	u64 v[16];
  	size_t i;
  
  	for (i = 0; i < 16; ++i)
  		m[i] = get_unaligned_le64(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] = blake2b_IV[4] ^ S->t[0];
  	v[13] = blake2b_IV[5] ^ S->t[1];
  	v[14] = blake2b_IV[6] ^ S->f[0];
  	v[15] = blake2b_IV[7] ^ S->f[1];
  
  	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

  struct blake2b_tfm_ctx {

  	u8 key[BLAKE2B_KEYBYTES];
  	unsigned int keylen;
  };

  static int blake2b_setkey(struct crypto_shash *tfm, const u8 *key,
  			  unsigned int keylen)

  {

  	struct blake2b_tfm_ctx *tctx = crypto_shash_ctx(tfm);

  
  	if (keylen == 0 || keylen > BLAKE2B_KEYBYTES) {
  		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  		return -EINVAL;
  	}

  	memcpy(tctx->key, key, keylen);
  	tctx->keylen = keylen;

  
  	return 0;
  }

  static int blake2b_init(struct shash_desc *desc)

  {

  	struct blake2b_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);

  	struct blake2b_state *state = shash_desc_ctx(desc);
  	const int digestsize = crypto_shash_digestsize(desc->tfm);

  	memset(state, 0, sizeof(*state));
  	memcpy(state->h, blake2b_IV, sizeof(state->h));
  
  	/* Parameter block is all zeros except index 0, no xor for 1..7 */

  	state->h[0] ^= 0x01010000 | tctx->keylen << 8 | digestsize;

  	if (tctx->keylen) {

  		/*
  		 * Prefill the buffer with the key, next call to _update or
  		 * _final will process it
  		 */

  		memcpy(state->buf, tctx->key, tctx->keylen);

  		state->buflen = BLAKE2B_BLOCKBYTES;

  	}

  	return 0;
  }

  static int blake2b_update(struct shash_desc *desc, const u8 *in,
  			  unsigned int inlen)

  {
  	struct blake2b_state *state = shash_desc_ctx(desc);

  	const size_t left = state->buflen;
  	const size_t fill = BLAKE2B_BLOCKBYTES - left;
  
  	if (!inlen)
  		return 0;
  
  	if (inlen > fill) {
  		state->buflen = 0;
  		/* Fill buffer */
  		memcpy(state->buf + left, in, fill);
  		blake2b_increment_counter(state, BLAKE2B_BLOCKBYTES);
  		/* Compress */
  		blake2b_compress(state, state->buf);
  		in += fill;
  		inlen -= fill;
  		while (inlen > BLAKE2B_BLOCKBYTES) {
  			blake2b_increment_counter(state, BLAKE2B_BLOCKBYTES);
  			blake2b_compress(state, in);
  			in += BLAKE2B_BLOCKBYTES;
  			inlen -= BLAKE2B_BLOCKBYTES;
  		}
  	}
  	memcpy(state->buf + state->buflen, in, inlen);
  	state->buflen += inlen;

  	return 0;
  }

  static int blake2b_final(struct shash_desc *desc, u8 *out)

  {
  	struct blake2b_state *state = shash_desc_ctx(desc);
  	const int digestsize = crypto_shash_digestsize(desc->tfm);

  	size_t i;
  
  	blake2b_increment_counter(state, state->buflen);

  	/* Set last block */
  	state->f[0] = (u64)-1;

  	/* Padding */
  	memset(state->buf + state->buflen, 0, BLAKE2B_BLOCKBYTES - state->buflen);
  	blake2b_compress(state, state->buf);
  
  	/* Avoid temporary buffer and switch the internal output to LE order */
  	for (i = 0; i < ARRAY_SIZE(state->h); i++)
  		__cpu_to_le64s(&state->h[i]);

  	memcpy(out, state->h, digestsize);

  	return 0;
  }
  
  static struct shash_alg blake2b_algs[] = {
  	{
  		.base.cra_name		= "blake2b-160",
  		.base.cra_driver_name	= "blake2b-160-generic",
  		.base.cra_priority	= 100,
  		.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
  		.base.cra_blocksize	= BLAKE2B_BLOCKBYTES,

  		.base.cra_ctxsize	= sizeof(struct blake2b_tfm_ctx),

  		.base.cra_module	= THIS_MODULE,
  		.digestsize		= BLAKE2B_160_DIGEST_SIZE,

  		.setkey			= blake2b_setkey,

  		.init			= blake2b_init,

  		.update			= blake2b_update,

  		.final			= blake2b_final,

  		.descsize		= sizeof(struct blake2b_state),
  	}, {
  		.base.cra_name		= "blake2b-256",
  		.base.cra_driver_name	= "blake2b-256-generic",
  		.base.cra_priority	= 100,
  		.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
  		.base.cra_blocksize	= BLAKE2B_BLOCKBYTES,

  		.base.cra_ctxsize	= sizeof(struct blake2b_tfm_ctx),

  		.base.cra_module	= THIS_MODULE,
  		.digestsize		= BLAKE2B_256_DIGEST_SIZE,

  		.setkey			= blake2b_setkey,

  		.init			= blake2b_init,

  		.update			= blake2b_update,

  		.final			= blake2b_final,

  		.descsize		= sizeof(struct blake2b_state),
  	}, {
  		.base.cra_name		= "blake2b-384",
  		.base.cra_driver_name	= "blake2b-384-generic",
  		.base.cra_priority	= 100,
  		.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
  		.base.cra_blocksize	= BLAKE2B_BLOCKBYTES,

  		.base.cra_ctxsize	= sizeof(struct blake2b_tfm_ctx),

  		.base.cra_module	= THIS_MODULE,
  		.digestsize		= BLAKE2B_384_DIGEST_SIZE,

  		.setkey			= blake2b_setkey,

  		.init			= blake2b_init,

  		.update			= blake2b_update,

  		.final			= blake2b_final,

  		.descsize		= sizeof(struct blake2b_state),
  	}, {
  		.base.cra_name		= "blake2b-512",
  		.base.cra_driver_name	= "blake2b-512-generic",
  		.base.cra_priority	= 100,
  		.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
  		.base.cra_blocksize	= BLAKE2B_BLOCKBYTES,

  		.base.cra_ctxsize	= sizeof(struct blake2b_tfm_ctx),

  		.base.cra_module	= THIS_MODULE,
  		.digestsize		= BLAKE2B_512_DIGEST_SIZE,

  		.setkey			= blake2b_setkey,

  		.init			= blake2b_init,

  		.update			= blake2b_update,

  		.final			= blake2b_final,

  		.descsize		= sizeof(struct blake2b_state),
  	}
  };
  
  static int __init blake2b_mod_init(void)
  {

  	return crypto_register_shashes(blake2b_algs, ARRAY_SIZE(blake2b_algs));
  }
  
  static void __exit blake2b_mod_fini(void)
  {
  	crypto_unregister_shashes(blake2b_algs, ARRAY_SIZE(blake2b_algs));
  }
  
  subsys_initcall(blake2b_mod_init);
  module_exit(blake2b_mod_fini);
  
  MODULE_AUTHOR("David Sterba <kdave@kernel.org>");
  MODULE_DESCRIPTION("BLAKE2b generic implementation");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_CRYPTO("blake2b-160");
  MODULE_ALIAS_CRYPTO("blake2b-160-generic");
  MODULE_ALIAS_CRYPTO("blake2b-256");
  MODULE_ALIAS_CRYPTO("blake2b-256-generic");
  MODULE_ALIAS_CRYPTO("blake2b-384");
  MODULE_ALIAS_CRYPTO("blake2b-384-generic");
  MODULE_ALIAS_CRYPTO("blake2b-512");
  MODULE_ALIAS_CRYPTO("blake2b-512-generic");