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sha256_generic.c

/*
 * Cryptographic API.
 *
 * SHA-256, as specified in
 * http://csrc.nist.gov/cryptval/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>
 *
 * 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 <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/crypto.h>
#include <linux/types.h>
#include <crypto/sha.h>
#include <asm/byteorder.h>

struct sha256_ctx {
      u32 count[2];
      u32 state[8];
      u8 buf[128];
};

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 void sha256_init(struct crypto_tfm *tfm)
{
      struct sha256_ctx *sctx = crypto_tfm_ctx(tfm);
      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] = sctx->count[1] = 0;
}

static void sha256_update(struct crypto_tfm *tfm, const u8 *data,
                    unsigned int len)
{
      struct sha256_ctx *sctx = crypto_tfm_ctx(tfm);
      unsigned int i, index, part_len;

      /* Compute number of bytes mod 128 */
      index = (unsigned int)((sctx->count[0] >> 3) & 0x3f);

      /* Update number of bits */
      if ((sctx->count[0] += (len << 3)) < (len << 3)) {
            sctx->count[1]++;
            sctx->count[1] += (len >> 29);
      }

      part_len = 64 - index;

      /* Transform as many times as possible. */
      if (len >= part_len) {
            memcpy(&sctx->buf[index], data, part_len);
            sha256_transform(sctx->state, sctx->buf);

            for (i = part_len; i + 63 < len; i += 64)
                  sha256_transform(sctx->state, &data[i]);
            index = 0;
      } else {
            i = 0;
      }
      
      /* Buffer remaining input */
      memcpy(&sctx->buf[index], &data[i], len-i);
}

static void sha256_final(struct crypto_tfm *tfm, u8 *out)
{
      struct sha256_ctx *sctx = crypto_tfm_ctx(tfm);
      __be32 *dst = (__be32 *)out;
      __be32 bits[2];
      unsigned int index, pad_len;
      int i;
      static const u8 padding[64] = { 0x80, };

      /* Save number of bits */
      bits[1] = cpu_to_be32(sctx->count[0]);
      bits[0] = cpu_to_be32(sctx->count[1]);

      /* Pad out to 56 mod 64. */
      index = (sctx->count[0] >> 3) & 0x3f;
      pad_len = (index < 56) ? (56 - index) : ((64+56) - index);
      sha256_update(tfm, padding, pad_len);

      /* Append length (before padding) */
      sha256_update(tfm, (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));
}


static struct crypto_alg alg = {
      .cra_name   =     "sha256",
      .cra_driver_name= "sha256-generic",
      .cra_flags  =     CRYPTO_ALG_TYPE_DIGEST,
      .cra_blocksize    =     SHA256_BLOCK_SIZE,
      .cra_ctxsize      =     sizeof(struct sha256_ctx),
      .cra_module =     THIS_MODULE,
      .cra_alignmask    =     3,
      .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
      .cra_u            =     { .digest = {
      .dia_digestsize   =     SHA256_DIGEST_SIZE,
      .dia_init         =     sha256_init,
      .dia_update       =     sha256_update,
      .dia_final        =     sha256_final } }
};

static int __init init(void)
{
      return crypto_register_alg(&alg);
}

static void __exit fini(void)
{
      crypto_unregister_alg(&alg);
}

module_init(init);
module_exit(fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA256 Secure Hash Algorithm");

MODULE_ALIAS("sha256");

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