// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * 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>
   * Copyright (c) 2014 Red Hat Inc.

   */
  
  #include <linux/bitops.h>

  #include <linux/export.h>

  #include <linux/module.h>

  #include <linux/string.h>

  #include <crypto/sha.h>

  #include <asm/unaligned.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] = get_unaligned_be32((__u32 *)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;

  	memzero_explicit(W, 64 * sizeof(u32));

  }

  void sha256_update(struct sha256_state *sctx, const u8 *data, unsigned int len)

  {
  	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);

  }

  EXPORT_SYMBOL(sha256_update);

  void sha224_update(struct sha256_state *sctx, const u8 *data, unsigned int len)

  {

  	sha256_update(sctx, data, len);

  }
  EXPORT_SYMBOL(sha224_update);

  static void __sha256_final(struct sha256_state *sctx, u8 *out, int digest_words)

  {
  	__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(sctx, padding, pad_len);
  
  	/* Append length (before padding) */
  	sha256_update(sctx, (const u8 *)&bits, sizeof(bits));
  
  	/* Store state in digest */

  	for (i = 0; i < digest_words; i++)

  		put_unaligned_be32(sctx->state[i], &dst[i]);

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

  }

  void sha256_final(struct sha256_state *sctx, u8 *out)

  {

  	__sha256_final(sctx, out, 8);

  }

  EXPORT_SYMBOL(sha256_final);

  void sha224_final(struct sha256_state *sctx, u8 *out)

  {

  	__sha256_final(sctx, out, 7);

  }
  EXPORT_SYMBOL(sha224_final);

  void sha256(const u8 *data, unsigned int len, u8 *out)
  {
  	struct sha256_state sctx;
  
  	sha256_init(&sctx);
  	sha256_update(&sctx, data, len);
  	sha256_final(&sctx, out);
  }
  EXPORT_SYMBOL(sha256);

  MODULE_LICENSE("GPL");