/*
 * Cryptographic API.
 *
 * SHA-256, as specified in
 * http://csrc.nist.gov/groups/STM/cavp/documents/shs/sha256-384-512.pdf
 *
 * SHA-256 code by Jean-Luc Cooke <jlcooke@certainkey.com>.
 *
 * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * SHA224 Support Copyright 2007 Intel Corporation <jonathan.lynch@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */
#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/types.h>
#include <crypto/sha.h>
#include <asm/byteorder.h>

static inline u32 Ch(u32 x, u32 y, u32 z) {
  return z ^ (x & (y ^ z));
}

static inline u32 Maj(u32 x, u32 y, u32 z) {
  return (x & y) | (z & (x | y));
}

#define e0(x) (ror32(x, 2) ^ ror32(x, 13) ^ ror32(x, 22))
#define e1(x) (ror32(x, 6) ^ ror32(x, 11) ^ ror32(x, 25))
#define s0(x) (ror32(x, 7) ^ ror32(x, 18) ^ (x >> 3))
#define s1(x) (ror32(x, 17) ^ ror32(x, 19) ^ (x >> 10))

static inline void LOAD_OP(int I, u32* W, const u8* input) {
  W[I] = __be32_to_cpu(((__be32*)(input))[I]);
}

static inline void BLEND_OP(int I, u32* W) {
  W[I] = s1(W[I - 2]) + W[I - 7] + s0(W[I - 15]) + W[I - 16];
}

static void sha256_transform(u32* state, const u8* input) {
  u32 a, b, c, d, e, f, g, h, t1, t2;
  u32 W[64];
  int i;

  /* load the input */
  for (i = 0; i < 16; i++)
    LOAD_OP(i, W, input);

  /* now blend */
  for (i = 16; i < 64; i++)
    BLEND_OP(i, W);

  /* load the state into our registers */
  a = state[0];
  b = state[1];
  c = state[2];
  d = state[3];
  e = state[4];
  f = state[5];
  g = state[6];
  h = state[7];

  /* now iterate */
  t1 = h + e1(e) + Ch(e, f, g) + 0x428a2f98 + W[0];
  t2 = e0(a) + Maj(a, b, c);
  d += t1;
  h = t1 + t2;
  t1 = g + e1(d) + Ch(d, e, f) + 0x71374491 + W[1];
  t2 = e0(h) + Maj(h, a, b);
  c += t1;
  g = t1 + t2;
  t1 = f + e1(c) + Ch(c, d, e) + 0xb5c0fbcf + W[2];
  t2 = e0(g) + Maj(g, h, a);
  b += t1;
  f = t1 + t2;
  t1 = e + e1(b) + Ch(b, c, d) + 0xe9b5dba5 + W[3];
  t2 = e0(f) + Maj(f, g, h);
  a += t1;
  e = t1 + t2;
  t1 = d + e1(a) + Ch(a, b, c) + 0x3956c25b + W[4];
  t2 = e0(e) + Maj(e, f, g);
  h += t1;
  d = t1 + t2;
  t1 = c + e1(h) + Ch(h, a, b) + 0x59f111f1 + W[5];
  t2 = e0(d) + Maj(d, e, f);
  g += t1;
  c = t1 + t2;
  t1 = b + e1(g) + Ch(g, h, a) + 0x923f82a4 + W[6];
  t2 = e0(c) + Maj(c, d, e);
  f += t1;
  b = t1 + t2;
  t1 = a + e1(f) + Ch(f, g, h) + 0xab1c5ed5 + W[7];
  t2 = e0(b) + Maj(b, c, d);
  e += t1;
  a = t1 + t2;

  t1 = h + e1(e) + Ch(e, f, g) + 0xd807aa98 + W[8];
  t2 = e0(a) + Maj(a, b, c);
  d += t1;
  h = t1 + t2;
  t1 = g + e1(d) + Ch(d, e, f) + 0x12835b01 + W[9];
  t2 = e0(h) + Maj(h, a, b);
  c += t1;
  g = t1 + t2;
  t1 = f + e1(c) + Ch(c, d, e) + 0x243185be + W[10];
  t2 = e0(g) + Maj(g, h, a);
  b += t1;
  f = t1 + t2;
  t1 = e + e1(b) + Ch(b, c, d) + 0x550c7dc3 + W[11];
  t2 = e0(f) + Maj(f, g, h);
  a += t1;
  e = t1 + t2;
  t1 = d + e1(a) + Ch(a, b, c) + 0x72be5d74 + W[12];
  t2 = e0(e) + Maj(e, f, g);
  h += t1;
  d = t1 + t2;
  t1 = c + e1(h) + Ch(h, a, b) + 0x80deb1fe + W[13];
  t2 = e0(d) + Maj(d, e, f);
  g += t1;
  c = t1 + t2;
  t1 = b + e1(g) + Ch(g, h, a) + 0x9bdc06a7 + W[14];
  t2 = e0(c) + Maj(c, d, e);
  f += t1;
  b = t1 + t2;
  t1 = a + e1(f) + Ch(f, g, h) + 0xc19bf174 + W[15];
  t2 = e0(b) + Maj(b, c, d);
  e += t1;
  a = t1 + t2;

  t1 = h + e1(e) + Ch(e, f, g) + 0xe49b69c1 + W[16];
  t2 = e0(a) + Maj(a, b, c);
  d += t1;
  h = t1 + t2;
  t1 = g + e1(d) + Ch(d, e, f) + 0xefbe4786 + W[17];
  t2 = e0(h) + Maj(h, a, b);
  c += t1;
  g = t1 + t2;
  t1 = f + e1(c) + Ch(c, d, e) + 0x0fc19dc6 + W[18];
  t2 = e0(g) + Maj(g, h, a);
  b += t1;
  f = t1 + t2;
  t1 = e + e1(b) + Ch(b, c, d) + 0x240ca1cc + W[19];
  t2 = e0(f) + Maj(f, g, h);
  a += t1;
  e = t1 + t2;
  t1 = d + e1(a) + Ch(a, b, c) + 0x2de92c6f + W[20];
  t2 = e0(e) + Maj(e, f, g);
  h += t1;
  d = t1 + t2;
  t1 = c + e1(h) + Ch(h, a, b) + 0x4a7484aa + W[21];
  t2 = e0(d) + Maj(d, e, f);
  g += t1;
  c = t1 + t2;
  t1 = b + e1(g) + Ch(g, h, a) + 0x5cb0a9dc + W[22];
  t2 = e0(c) + Maj(c, d, e);
  f += t1;
  b = t1 + t2;
  t1 = a + e1(f) + Ch(f, g, h) + 0x76f988da + W[23];
  t2 = e0(b) + Maj(b, c, d);
  e += t1;
  a = t1 + t2;

  t1 = h + e1(e) + Ch(e, f, g) + 0x983e5152 + W[24];
  t2 = e0(a) + Maj(a, b, c);
  d += t1;
  h = t1 + t2;
  t1 = g + e1(d) + Ch(d, e, f) + 0xa831c66d + W[25];
  t2 = e0(h) + Maj(h, a, b);
  c += t1;
  g = t1 + t2;
  t1 = f + e1(c) + Ch(c, d, e) + 0xb00327c8 + W[26];
  t2 = e0(g) + Maj(g, h, a);
  b += t1;
  f = t1 + t2;
  t1 = e + e1(b) + Ch(b, c, d) + 0xbf597fc7 + W[27];
  t2 = e0(f) + Maj(f, g, h);
  a += t1;
  e = t1 + t2;
  t1 = d + e1(a) + Ch(a, b, c) + 0xc6e00bf3 + W[28];
  t2 = e0(e) + Maj(e, f, g);
  h += t1;
  d = t1 + t2;
  t1 = c + e1(h) + Ch(h, a, b) + 0xd5a79147 + W[29];
  t2 = e0(d) + Maj(d, e, f);
  g += t1;
  c = t1 + t2;
  t1 = b + e1(g) + Ch(g, h, a) + 0x06ca6351 + W[30];
  t2 = e0(c) + Maj(c, d, e);
  f += t1;
  b = t1 + t2;
  t1 = a + e1(f) + Ch(f, g, h) + 0x14292967 + W[31];
  t2 = e0(b) + Maj(b, c, d);
  e += t1;
  a = t1 + t2;

  t1 = h + e1(e) + Ch(e, f, g) + 0x27b70a85 + W[32];
  t2 = e0(a) + Maj(a, b, c);
  d += t1;
  h = t1 + t2;
  t1 = g + e1(d) + Ch(d, e, f) + 0x2e1b2138 + W[33];
  t2 = e0(h) + Maj(h, a, b);
  c += t1;
  g = t1 + t2;
  t1 = f + e1(c) + Ch(c, d, e) + 0x4d2c6dfc + W[34];
  t2 = e0(g) + Maj(g, h, a);
  b += t1;
  f = t1 + t2;
  t1 = e + e1(b) + Ch(b, c, d) + 0x53380d13 + W[35];
  t2 = e0(f) + Maj(f, g, h);
  a += t1;
  e = t1 + t2;
  t1 = d + e1(a) + Ch(a, b, c) + 0x650a7354 + W[36];
  t2 = e0(e) + Maj(e, f, g);
  h += t1;
  d = t1 + t2;
  t1 = c + e1(h) + Ch(h, a, b) + 0x766a0abb + W[37];
  t2 = e0(d) + Maj(d, e, f);
  g += t1;
  c = t1 + t2;
  t1 = b + e1(g) + Ch(g, h, a) + 0x81c2c92e + W[38];
  t2 = e0(c) + Maj(c, d, e);
  f += t1;
  b = t1 + t2;
  t1 = a + e1(f) + Ch(f, g, h) + 0x92722c85 + W[39];
  t2 = e0(b) + Maj(b, c, d);
  e += t1;
  a = t1 + t2;

  t1 = h + e1(e) + Ch(e, f, g) + 0xa2bfe8a1 + W[40];
  t2 = e0(a) + Maj(a, b, c);
  d += t1;
  h = t1 + t2;
  t1 = g + e1(d) + Ch(d, e, f) + 0xa81a664b + W[41];
  t2 = e0(h) + Maj(h, a, b);
  c += t1;
  g = t1 + t2;
  t1 = f + e1(c) + Ch(c, d, e) + 0xc24b8b70 + W[42];
  t2 = e0(g) + Maj(g, h, a);
  b += t1;
  f = t1 + t2;
  t1 = e + e1(b) + Ch(b, c, d) + 0xc76c51a3 + W[43];
  t2 = e0(f) + Maj(f, g, h);
  a += t1;
  e = t1 + t2;
  t1 = d + e1(a) + Ch(a, b, c) + 0xd192e819 + W[44];
  t2 = e0(e) + Maj(e, f, g);
  h += t1;
  d = t1 + t2;
  t1 = c + e1(h) + Ch(h, a, b) + 0xd6990624 + W[45];
  t2 = e0(d) + Maj(d, e, f);
  g += t1;
  c = t1 + t2;
  t1 = b + e1(g) + Ch(g, h, a) + 0xf40e3585 + W[46];
  t2 = e0(c) + Maj(c, d, e);
  f += t1;
  b = t1 + t2;
  t1 = a + e1(f) + Ch(f, g, h) + 0x106aa070 + W[47];
  t2 = e0(b) + Maj(b, c, d);
  e += t1;
  a = t1 + t2;

  t1 = h + e1(e) + Ch(e, f, g) + 0x19a4c116 + W[48];
  t2 = e0(a) + Maj(a, b, c);
  d += t1;
  h = t1 + t2;
  t1 = g + e1(d) + Ch(d, e, f) + 0x1e376c08 + W[49];
  t2 = e0(h) + Maj(h, a, b);
  c += t1;
  g = t1 + t2;
  t1 = f + e1(c) + Ch(c, d, e) + 0x2748774c + W[50];
  t2 = e0(g) + Maj(g, h, a);
  b += t1;
  f = t1 + t2;
  t1 = e + e1(b) + Ch(b, c, d) + 0x34b0bcb5 + W[51];
  t2 = e0(f) + Maj(f, g, h);
  a += t1;
  e = t1 + t2;
  t1 = d + e1(a) + Ch(a, b, c) + 0x391c0cb3 + W[52];
  t2 = e0(e) + Maj(e, f, g);
  h += t1;
  d = t1 + t2;
  t1 = c + e1(h) + Ch(h, a, b) + 0x4ed8aa4a + W[53];
  t2 = e0(d) + Maj(d, e, f);
  g += t1;
  c = t1 + t2;
  t1 = b + e1(g) + Ch(g, h, a) + 0x5b9cca4f + W[54];
  t2 = e0(c) + Maj(c, d, e);
  f += t1;
  b = t1 + t2;
  t1 = a + e1(f) + Ch(f, g, h) + 0x682e6ff3 + W[55];
  t2 = e0(b) + Maj(b, c, d);
  e += t1;
  a = t1 + t2;

  t1 = h + e1(e) + Ch(e, f, g) + 0x748f82ee + W[56];
  t2 = e0(a) + Maj(a, b, c);
  d += t1;
  h = t1 + t2;
  t1 = g + e1(d) + Ch(d, e, f) + 0x78a5636f + W[57];
  t2 = e0(h) + Maj(h, a, b);
  c += t1;
  g = t1 + t2;
  t1 = f + e1(c) + Ch(c, d, e) + 0x84c87814 + W[58];
  t2 = e0(g) + Maj(g, h, a);
  b += t1;
  f = t1 + t2;
  t1 = e + e1(b) + Ch(b, c, d) + 0x8cc70208 + W[59];
  t2 = e0(f) + Maj(f, g, h);
  a += t1;
  e = t1 + t2;
  t1 = d + e1(a) + Ch(a, b, c) + 0x90befffa + W[60];
  t2 = e0(e) + Maj(e, f, g);
  h += t1;
  d = t1 + t2;
  t1 = c + e1(h) + Ch(h, a, b) + 0xa4506ceb + W[61];
  t2 = e0(d) + Maj(d, e, f);
  g += t1;
  c = t1 + t2;
  t1 = b + e1(g) + Ch(g, h, a) + 0xbef9a3f7 + W[62];
  t2 = e0(c) + Maj(c, d, e);
  f += t1;
  b = t1 + t2;
  t1 = a + e1(f) + Ch(f, g, h) + 0xc67178f2 + W[63];
  t2 = e0(b) + Maj(b, c, d);
  e += t1;
  a = t1 + t2;

  state[0] += a;
  state[1] += b;
  state[2] += c;
  state[3] += d;
  state[4] += e;
  state[5] += f;
  state[6] += g;
  state[7] += h;

  /* clear any sensitive info... */
  a = b = c = d = e = f = g = h = t1 = t2 = 0;
  memset(W, 0, 64 * sizeof(u32));
}

static int sha224_init(struct shash_desc* desc) {
  struct sha256_state* sctx = shash_desc_ctx(desc);
  sctx->state[0] = SHA224_H0;
  sctx->state[1] = SHA224_H1;
  sctx->state[2] = SHA224_H2;
  sctx->state[3] = SHA224_H3;
  sctx->state[4] = SHA224_H4;
  sctx->state[5] = SHA224_H5;
  sctx->state[6] = SHA224_H6;
  sctx->state[7] = SHA224_H7;
  sctx->count = 0;

  return 0;
}

static int sha256_init(struct shash_desc* desc) {
  struct sha256_state* sctx = shash_desc_ctx(desc);
  sctx->state[0] = SHA256_H0;
  sctx->state[1] = SHA256_H1;
  sctx->state[2] = SHA256_H2;
  sctx->state[3] = SHA256_H3;
  sctx->state[4] = SHA256_H4;
  sctx->state[5] = SHA256_H5;
  sctx->state[6] = SHA256_H6;
  sctx->state[7] = SHA256_H7;
  sctx->count = 0;

  return 0;
}

static int sha256_update(struct shash_desc* desc,
                         const u8* data,
                         unsigned int len) {
  struct sha256_state* sctx = shash_desc_ctx(desc);
  unsigned int partial, done;
  const u8* src;

  partial = sctx->count & 0x3f;
  sctx->count += len;
  done = 0;
  src = data;

  if ((partial + len) > 63) {
    if (partial) {
      done = -partial;
      memcpy(sctx->buf + partial, data, done + 64);
      src = sctx->buf;
    }

    do {
      sha256_transform(sctx->state, src);
      done += 64;
      src = data + done;
    } while (done + 63 < len);

    partial = 0;
  }
  memcpy(sctx->buf + partial, src, len - done);

  return 0;
}

static int sha256_final(struct shash_desc* desc, u8* out) {
  struct sha256_state* sctx = shash_desc_ctx(desc);
  __be32* dst = (__be32*)out;
  __be64 bits;
  unsigned int index, pad_len;
  int i;
  static const u8 padding[64] = {
      0x80,
  };

  /* Save number of bits */
  bits = __cpu_to_be64(sctx->count << 3);

  /* Pad out to 56 mod 64. */
  index = sctx->count & 0x3f;
  pad_len = (index < 56) ? (56 - index) : ((64 + 56) - index);
  sha256_update(desc, padding, pad_len);

  /* Append length (before padding) */
  sha256_update(desc, (const u8*)&bits, sizeof(bits));

  /* Store state in digest */
  for (i = 0; i < 8; i++)
    dst[i] = __cpu_to_be32(sctx->state[i]);

  /* Zeroize sensitive information. */
  memset(sctx, 0, sizeof(*sctx));

  return 0;
}

static int sha224_final(struct shash_desc* desc, u8* hash) {
  u8 D[SHA256_DIGEST_SIZE];

  sha256_final(desc, D);

  memcpy(hash, D, SHA224_DIGEST_SIZE);
  memset(D, 0, SHA256_DIGEST_SIZE);

  return 0;
}

static int sha256_export(struct shash_desc* desc, void* out) {
  struct sha256_state* sctx = shash_desc_ctx(desc);

  memcpy(out, sctx, sizeof(*sctx));
  return 0;
}

static int sha256_import(struct shash_desc* desc, const void* in) {
  struct sha256_state* sctx = shash_desc_ctx(desc);

  memcpy(sctx, in, sizeof(*sctx));
  return 0;
}

struct shash_alg sha256 = {.digestsize = SHA256_DIGEST_SIZE,
                           .init = sha256_init,
                           .update = sha256_update,
                           .final = sha256_final,
                           .export = sha256_export,
                           .import = sha256_import,
                           .descsize = sizeof(struct sha256_state),
                           .statesize = sizeof(struct sha256_state),
                           .base = {
                               .cra_name = "sha256",
                               .cra_driver_name = "sha256-generic",
                               .cra_flags = CRYPTO_ALG_TYPE_SHASH,
                               .cra_blocksize = SHA256_BLOCK_SIZE,
                               .cra_module = NULL,
                           }};

struct shash_alg sha224 = {.digestsize = SHA224_DIGEST_SIZE,
                           .init = sha224_init,
                           .update = sha256_update,
                           .final = sha224_final,
                           .descsize = sizeof(struct sha256_state),
                           .base = {
                               .cra_name = "sha224",
                               .cra_driver_name = "sha224-generic",
                               .cra_flags = CRYPTO_ALG_TYPE_SHASH,
                               .cra_blocksize = SHA224_BLOCK_SIZE,
                               .cra_module = NULL,
                           }};

static int __init sha256_generic_mod_init(void) {
  int ret = 0;

  ret = crypto_register_shash(&sha224);

  if (ret < 0)
    return ret;

  ret = crypto_register_shash(&sha256);

  if (ret < 0)
    crypto_unregister_shash(&sha224);

  return ret;
}

static void __exit sha256_generic_mod_fini(void) {
  crypto_unregister_shash(&sha224);
  crypto_unregister_shash(&sha256);
}

module_init(sha256_generic_mod_init);
module_exit(sha256_generic_mod_fini);