sha256-internal.c

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/*
 * SHA-256 hash implementation and interface functions
 * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "sha256.h"
#include "crypto.h"

struct sha256_state {
        u64 length;
        u32 state[8], curlen;
        u8 buf[64];
};

static void sha256_init(struct sha256_state *md);
static int sha256_process(struct sha256_state *md, const unsigned char *in,
                          unsigned long inlen);
static int sha256_done(struct sha256_state *md, unsigned char *out);


int sha256_vector(size_t num_elem, const u8 *addr[], const size_t *len,
                  u8 *mac)
{
        struct sha256_state ctx;
        size_t i;

        sha256_init(&ctx);
        for (i = 0; i < num_elem; i++)
                if (sha256_process(&ctx, addr[i], len[i]))
                        return -1;
        if (sha256_done(&ctx, mac))
                return -1;
        return 0;
}


/* ===== start - public domain SHA256 implementation ===== */

/* This is based on SHA256 implementation in LibTomCrypt that was released into
 * public domain by Tom St Denis. */

/* the K array */
static const unsigned long K[64] = {
        0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL, 0x3956c25bUL,
        0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL, 0xd807aa98UL, 0x12835b01UL,
        0x243185beUL, 0x550c7dc3UL, 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL,
        0xc19bf174UL, 0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
        0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL, 0x983e5152UL,
        0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL, 0xc6e00bf3UL, 0xd5a79147UL,
        0x06ca6351UL, 0x14292967UL, 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL,
        0x53380d13UL, 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
        0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL, 0xd192e819UL,
        0xd6990624UL, 0xf40e3585UL, 0x106aa070UL, 0x19a4c116UL, 0x1e376c08UL,
        0x2748774cUL, 0x34b0bcb5UL, 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL,
        0x682e6ff3UL, 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
        0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
};


/* Various logical functions */
#define RORc(x, y) \
( ((((unsigned long) (x) & 0xFFFFFFFFUL) >> (unsigned long) ((y) & 31)) | \
   ((unsigned long) (x) << (unsigned long) (32 - ((y) & 31)))) & 0xFFFFFFFFUL)
#define Ch(x,y,z)       (z ^ (x & (y ^ z)))
#define Maj(x,y,z)      (((x | y) & z) | (x & y)) 
#define S(x, n)         RORc((x), (n))
#define R(x, n)         (((x)&0xFFFFFFFFUL)>>(n))
#define Sigma0(x)       (S(x, 2) ^ S(x, 13) ^ S(x, 22))
#define Sigma1(x)       (S(x, 6) ^ S(x, 11) ^ S(x, 25))
#define Gamma0(x)       (S(x, 7) ^ S(x, 18) ^ R(x, 3))
#define Gamma1(x)       (S(x, 17) ^ S(x, 19) ^ R(x, 10))
#ifndef MIN
#define MIN(x, y) (((x) < (y)) ? (x) : (y))
#endif

/* compress 512-bits */
static int sha256_compress(struct sha256_state *md, unsigned char *buf)
{
        u32 S[8], W[64], t0, t1;
        u32 t;
        int i;

        /* copy state into S */
        for (i = 0; i < 8; i++) {
                S[i] = md->state[i];
        }

        /* copy the state into 512-bits into W[0..15] */
        for (i = 0; i < 16; i++)
                W[i] = WPA_GET_BE32(buf + (4 * i));

        /* fill W[16..63] */
        for (i = 16; i < 64; i++) {
                W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) +
                        W[i - 16];
        }        

        /* Compress */
#define RND(a,b,c,d,e,f,g,h,i)                          \
        t0 = h + Sigma1(e) + Ch(e, f, g) + K[i] + W[i]; \
        t1 = Sigma0(a) + Maj(a, b, c);                  \
        d += t0;                                        \
        h  = t0 + t1;

        for (i = 0; i < 64; ++i) {
                RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], i);
                t = S[7]; S[7] = S[6]; S[6] = S[5]; S[5] = S[4]; 
                S[4] = S[3]; S[3] = S[2]; S[2] = S[1]; S[1] = S[0]; S[0] = t;
        }

        /* feedback */
        for (i = 0; i < 8; i++) {
                md->state[i] = md->state[i] + S[i];
        }
        return 0;
}


/* Initialize the hash state */
static void sha256_init(struct sha256_state *md)
{
        md->curlen = 0;
        md->length = 0;
        md->state[0] = 0x6A09E667UL;
        md->state[1] = 0xBB67AE85UL;
        md->state[2] = 0x3C6EF372UL;
        md->state[3] = 0xA54FF53AUL;
        md->state[4] = 0x510E527FUL;
        md->state[5] = 0x9B05688CUL;
        md->state[6] = 0x1F83D9ABUL;
        md->state[7] = 0x5BE0CD19UL;
}

static int sha256_process(struct sha256_state *md, const unsigned char *in,
                          unsigned long inlen)
{
        unsigned long n;
#define block_size 64

        if (md->curlen > sizeof(md->buf))
                return -1;

        while (inlen > 0) {
                if (md->curlen == 0 && inlen >= block_size) {
                        if (sha256_compress(md, (unsigned char *) in) < 0)
                                return -1;
                        md->length += block_size * 8;
                        in += block_size;
                        inlen -= block_size;
                } else {
                        n = MIN(inlen, (block_size - md->curlen));
                        os_memcpy(md->buf + md->curlen, in, n);
                        md->curlen += n;
                        in += n;
                        inlen -= n;
                        if (md->curlen == block_size) {
                                if (sha256_compress(md, md->buf) < 0)
                                        return -1;
                                md->length += 8 * block_size;
                                md->curlen = 0;
                        }
                }
        }

        return 0;
}


static int sha256_done(struct sha256_state *md, unsigned char *out)
{
        int i;

        if (md->curlen >= sizeof(md->buf))
                return -1;

        /* increase the length of the message */
        md->length += md->curlen * 8;

        /* append the '1' bit */
        md->buf[md->curlen++] = (unsigned char) 0x80;

        /* if the length is currently above 56 bytes we append zeros
         * then compress.  Then we can fall back to padding zeros and length
         * encoding like normal.
         */
        if (md->curlen > 56) {
                while (md->curlen < 64) {
                        md->buf[md->curlen++] = (unsigned char) 0;
                }
                sha256_compress(md, md->buf);
                md->curlen = 0;
        }

        /* pad upto 56 bytes of zeroes */
        while (md->curlen < 56) {
                md->buf[md->curlen++] = (unsigned char) 0;
        }

        /* store length */
        WPA_PUT_BE64(md->buf + 56, md->length);
        sha256_compress(md, md->buf);

        /* copy output */
        for (i = 0; i < 8; i++)
                WPA_PUT_BE32(out + (4 * i), md->state[i]);

        return 0;
}

/* ===== end - public domain SHA256 implementation ===== */