/* vi: set sw=4 ts=4: */
/*
 * Based on shasum from http://www.netsw.org/crypto/hash/
 * Majorly hacked up to use Dr Brian Gladman's sha1 code
 *
 * Copyright (C) 2002 Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
 * Copyright (C) 2003 Glenn L. McGrath
 * Copyright (C) 2003 Erik Andersen
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 * ---------------------------------------------------------------------------
 * Issue Date: 10/11/2002
 *
 * This is a byte oriented version of SHA1 that operates on arrays of bytes
 * stored in memory. It runs at 22 cycles per byte on a Pentium P4 processor
 *
 * ---------------------------------------------------------------------------
 *
 * SHA256 and SHA512 parts are:
 * Released into the Public Domain by Ulrich Drepper <drepper@redhat.com>.
 * Shrank by Denys Vlasenko.
 *
 * ---------------------------------------------------------------------------
 *
 * The best way to test random blocksizes is to go to coreutils/md5_sha1_sum.c
 * and replace "4096" with something like "2000 + time(NULL) % 2097",
 * then rebuild and compare "shaNNNsum bigfile" results.
 */

#include "libbb.h"

#define rotl32(x,n) (((x) << (n)) | ((x) >> (32 - (n))))
#define rotr32(x,n) (((x) >> (n)) | ((x) << (32 - (n))))
/* for sha512: */
#define rotr64(x,n) (((x) >> (n)) | ((x) << (64 - (n))))
#if BB_LITTLE_ENDIAN
static inline uint64_t hton64(uint64_t v)
{
        return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
}
#else
#define hton64(v) (v)
#endif
#define ntoh64(v) hton64(v)

/* To check alignment gcc has an appropriate operator.  Other
   compilers don't.  */
#if defined(__GNUC__) && __GNUC__ >= 2
# define UNALIGNED_P(p,type) (((uintptr_t) p) % __alignof__(type) != 0)
#else
# define UNALIGNED_P(p,type) (((uintptr_t) p) % sizeof(type) != 0)
#endif


/* Some arch headers have conflicting defines */
#undef ch
#undef parity
#undef maj
#undef rnd

static void FAST_FUNC sha1_process_block64(sha1_ctx_t *ctx)
{
        unsigned t;
        uint32_t W[80], a, b, c, d, e;
        const uint32_t *words = (uint32_t*) ctx->wbuffer;

        for (t = 0; t < 16; ++t) {
                W[t] = ntohl(*words);
                words++;
        }

        for (/*t = 16*/; t < 80; ++t) {
                uint32_t T = W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16];
                W[t] = rotl32(T, 1);
        }

        a = ctx->hash[0];
        b = ctx->hash[1];
        c = ctx->hash[2];
        d = ctx->hash[3];
        e = ctx->hash[4];

/* Reverse byte order in 32-bit words   */
#define ch(x,y,z)        ((z) ^ ((x) & ((y) ^ (z))))
#define parity(x,y,z)    ((x) ^ (y) ^ (z))
#define maj(x,y,z)       (((x) & (y)) | ((z) & ((x) | (y))))
/* A normal version as set out in the FIPS. This version uses   */
/* partial loop unrolling and is optimised for the Pentium 4    */
#define rnd(f,k) \
        do { \
                uint32_t T = a; \
                a = rotl32(a, 5) + f(b, c, d) + e + k + W[t]; \
                e = d; \
                d = c; \
                c = rotl32(b, 30); \
                b = T; \
        } while (0)

        for (t = 0; t < 20; ++t)
                rnd(ch, 0x5a827999);

        for (/*t = 20*/; t < 40; ++t)
                rnd(parity, 0x6ed9eba1);

        for (/*t = 40*/; t < 60; ++t)
                rnd(maj, 0x8f1bbcdc);

        for (/*t = 60*/; t < 80; ++t)
                rnd(parity, 0xca62c1d6);
#undef ch
#undef parity
#undef maj
#undef rnd

        ctx->hash[0] += a;
        ctx->hash[1] += b;
        ctx->hash[2] += c;
        ctx->hash[3] += d;
        ctx->hash[4] += e;
}

/* Constants for SHA512 from FIPS 180-2:4.2.3.
 * SHA256 constants from FIPS 180-2:4.2.2
 * are the most significant half of first 64 elements
 * of the same array.
 */
static const uint64_t sha_K[80] = {
        0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL,
        0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
        0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
        0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
        0xd807aa98a3030242ULL, 0x12835b0145706fbeULL,
        0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
        0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL,
        0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
        0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
        0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
        0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL,
        0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
        0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL,
        0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
        0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
        0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
        0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL,
        0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
        0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL,
        0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
        0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
        0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
        0xd192e819d6ef5218ULL, 0xd69906245565a910ULL,
        0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
        0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL,
        0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
        0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
        0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
        0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL,
        0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
        0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL,
        0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
        0xca273eceea26619cULL, 0xd186b8c721c0c207ULL, /* [64]+ are used for sha512 only */
        0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
        0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL,
        0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
        0x28db77f523047d84ULL, 0x32caab7b40c72493ULL,
        0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
        0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
        0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL
};

#undef Ch
#undef Maj
#undef S0
#undef S1
#undef R0
#undef R1

static void FAST_FUNC sha256_process_block64(sha256_ctx_t *ctx)
{
        unsigned t;
        uint32_t W[64], a, b, c, d, e, f, g, h;
        const uint32_t *words = (uint32_t*) ctx->wbuffer;

        /* Operators defined in FIPS 180-2:4.1.2.  */
#define Ch(x, y, z) ((x & y) ^ (~x & z))
#define Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
#define S0(x) (rotr32(x, 2) ^ rotr32(x, 13) ^ rotr32(x, 22))
#define S1(x) (rotr32(x, 6) ^ rotr32(x, 11) ^ rotr32(x, 25))
#define R0(x) (rotr32(x, 7) ^ rotr32(x, 18) ^ (x >> 3))
#define R1(x) (rotr32(x, 17) ^ rotr32(x, 19) ^ (x >> 10))

        /* Compute the message schedule according to FIPS 180-2:6.2.2 step 2.  */
        for (t = 0; t < 16; ++t) {
                W[t] = ntohl(*words);
                words++;
        }

        for (/*t = 16*/; t < 64; ++t)
                W[t] = R1(W[t - 2]) + W[t - 7] + R0(W[t - 15]) + W[t - 16];

        a = ctx->hash[0];
        b = ctx->hash[1];
        c = ctx->hash[2];
        d = ctx->hash[3];
        e = ctx->hash[4];
        f = ctx->hash[5];
        g = ctx->hash[6];
        h = ctx->hash[7];

        /* The actual computation according to FIPS 180-2:6.2.2 step 3.  */
        for (t = 0; t < 64; ++t) {
                /* Need to fetch upper half of sha_K[t]
                 * (I hope compiler is clever enough to just fetch
                 * upper half)
                 */
                uint32_t K_t = sha_K[t] >> 32;
                uint32_t T1 = h + S1(e) + Ch(e, f, g) + K_t + W[t];
                uint32_t T2 = S0(a) + Maj(a, b, c);
                h = g;
                g = f;
                f = e;
                e = d + T1;
                d = c;
                c = b;
                b = a;
                a = T1 + T2;
        }
#undef Ch
#undef Maj
#undef S0
#undef S1
#undef R0
#undef R1
        /* Add the starting values of the context according to FIPS 180-2:6.2.2
           step 4.  */
        ctx->hash[0] += a;
        ctx->hash[1] += b;
        ctx->hash[2] += c;
        ctx->hash[3] += d;
        ctx->hash[4] += e;
        ctx->hash[5] += f;
        ctx->hash[6] += g;
        ctx->hash[7] += h;
}

static void FAST_FUNC sha512_process_block128(sha512_ctx_t *ctx)
{
        unsigned t;
        uint64_t W[80];
        /* On i386, having assignments here (not later as sha256 does)
         * produces 99 bytes smaller code with gcc 4.3.1
         */
        uint64_t a = ctx->hash[0];
        uint64_t b = ctx->hash[1];
        uint64_t c = ctx->hash[2];
        uint64_t d = ctx->hash[3];
        uint64_t e = ctx->hash[4];
        uint64_t f = ctx->hash[5];
        uint64_t g = ctx->hash[6];
        uint64_t h = ctx->hash[7];
        const uint64_t *words = (uint64_t*) ctx->wbuffer;

        /* Operators defined in FIPS 180-2:4.1.2.  */
#define Ch(x, y, z) ((x & y) ^ (~x & z))
#define Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
#define S0(x) (rotr64(x, 28) ^ rotr64(x, 34) ^ rotr64(x, 39))
#define S1(x) (rotr64(x, 14) ^ rotr64(x, 18) ^ rotr64(x, 41))
#define R0(x) (rotr64(x, 1) ^ rotr64(x, 8) ^ (x >> 7))
#define R1(x) (rotr64(x, 19) ^ rotr64(x, 61) ^ (x >> 6))

        /* Compute the message schedule according to FIPS 180-2:6.3.2 step 2.  */
        for (t = 0; t < 16; ++t) {
                W[t] = ntoh64(*words);
                words++;
        }
        for (/*t = 16*/; t < 80; ++t)
                W[t] = R1(W[t - 2]) + W[t - 7] + R0(W[t - 15]) + W[t - 16];

        /* The actual computation according to FIPS 180-2:6.3.2 step 3.  */
        for (t = 0; t < 80; ++t) {
                uint64_t T1 = h + S1(e) + Ch(e, f, g) + sha_K[t] + W[t];
                uint64_t T2 = S0(a) + Maj(a, b, c);
                h = g;
                g = f;
                f = e;
                e = d + T1;
                d = c;
                c = b;
                b = a;
                a = T1 + T2;
        }
#undef Ch
#undef Maj
#undef S0
#undef S1
#undef R0
#undef R1
        /* Add the starting values of the context according to FIPS 180-2:6.3.2
           step 4.  */
        ctx->hash[0] += a;
        ctx->hash[1] += b;
        ctx->hash[2] += c;
        ctx->hash[3] += d;
        ctx->hash[4] += e;
        ctx->hash[5] += f;
        ctx->hash[6] += g;
        ctx->hash[7] += h;
}


void FAST_FUNC sha1_begin(sha1_ctx_t *ctx)
{
        ctx->hash[0] = 0x67452301;
        ctx->hash[1] = 0xefcdab89;
        ctx->hash[2] = 0x98badcfe;
        ctx->hash[3] = 0x10325476;
        ctx->hash[4] = 0xc3d2e1f0;
        ctx->total64 = 0;
        ctx->process_block = sha1_process_block64;
}

static const uint32_t init256[] = {
        0x6a09e667,
        0xbb67ae85,
        0x3c6ef372,
        0xa54ff53a,
        0x510e527f,
        0x9b05688c,
        0x1f83d9ab,
        0x5be0cd19
};
static const uint32_t init512_lo[] = {
        0xf3bcc908,
        0x84caa73b,
        0xfe94f82b,
        0x5f1d36f1,
        0xade682d1,
        0x2b3e6c1f,
        0xfb41bd6b,
        0x137e2179
};

/* Initialize structure containing state of computation.
   (FIPS 180-2:5.3.2)  */
void FAST_FUNC sha256_begin(sha256_ctx_t *ctx)
{
        memcpy(ctx->hash, init256, sizeof(init256));
        ctx->total64 = 0;
        ctx->process_block = sha256_process_block64;
}

/* Initialize structure containing state of computation.
   (FIPS 180-2:5.3.3)  */
void FAST_FUNC sha512_begin(sha512_ctx_t *ctx)
{
        int i;
        for (i = 0; i < 8; i++)
                ctx->hash[i] = ((uint64_t)(init256[i]) << 32) + init512_lo[i];
        ctx->total64[0] = ctx->total64[1] = 0;
}


/* Used also for sha256 */
void FAST_FUNC sha1_hash(const void *buffer, size_t len, sha1_ctx_t *ctx)
{
        unsigned in_buf = ctx->total64 & 63;
        unsigned add = 64 - in_buf;

        ctx->total64 += len;

        while (len >= add) {    /* transfer whole blocks while possible  */
                memcpy(ctx->wbuffer + in_buf, buffer, add);
                buffer = (const char *)buffer + add;
                len -= add;
                add = 64;
                in_buf = 0;
                ctx->process_block(ctx);
        }

        memcpy(ctx->wbuffer + in_buf, buffer, len);
}

void FAST_FUNC sha512_hash(const void *buffer, size_t len, sha512_ctx_t *ctx)
{
        unsigned in_buf = ctx->total64[0] & 127;
        unsigned add = 128 - in_buf;

        /* First increment the byte count.  FIPS 180-2 specifies the possible
           length of the file up to 2^128 _bits_.
           We compute the number of _bytes_ and convert to bits later.  */
        ctx->total64[0] += len;
        if (ctx->total64[0] < len)
                ctx->total64[1]++;

        while (len >= add) {    /* transfer whole blocks while possible  */
                memcpy(ctx->wbuffer + in_buf, buffer, add);
                buffer = (const char *)buffer + add;
                len -= add;
                add = 128;
                in_buf = 0;
                sha512_process_block128(ctx);
        }

        memcpy(ctx->wbuffer + in_buf, buffer, len);
}


/* Used also for sha256 */
void FAST_FUNC sha1_end(void *resbuf, sha1_ctx_t *ctx)
{
        unsigned pad, in_buf;

        in_buf = ctx->total64 & 63;
        /* Pad the buffer to the next 64-byte boundary with 0x80,0,0,0... */
        ctx->wbuffer[in_buf++] = 0x80;

        /* This loop iterates either once or twice, no more, no less */
        while (1) {
                pad = 64 - in_buf;
                memset(ctx->wbuffer + in_buf, 0, pad);
                in_buf = 0;
                /* Do we have enough space for the length count? */
                if (pad >= 8) {
                        /* Store the 64-bit counter of bits in the buffer in BE format */
                        uint64_t t = ctx->total64 << 3;
                        t = hton64(t);
                        /* wbuffer is suitably aligned for this */
                        *(uint64_t *) (&ctx->wbuffer[64 - 8]) = t;
                }
                ctx->process_block(ctx);
                if (pad >= 8)
                        break;
        }

        in_buf = (ctx->process_block == sha1_process_block64) ? 5 : 8;
        /* This way we do not impose alignment constraints on resbuf: */
        if (BB_LITTLE_ENDIAN) {
                unsigned i;
                for (i = 0; i < in_buf; ++i)
                        ctx->hash[i] = htonl(ctx->hash[i]);
        }
        memcpy(resbuf, ctx->hash, sizeof(ctx->hash[0]) * in_buf);
}

void FAST_FUNC sha512_end(void *resbuf, sha512_ctx_t *ctx)
{
        unsigned pad, in_buf;

        in_buf = ctx->total64[0] & 127;
        /* Pad the buffer to the next 128-byte boundary with 0x80,0,0,0...
         * (FIPS 180-2:5.1.2)
         */
        ctx->wbuffer[in_buf++] = 0x80;

        while (1) {
                pad = 128 - in_buf;
                memset(ctx->wbuffer + in_buf, 0, pad);
                in_buf = 0;
                if (pad >= 16) {
                        /* Store the 128-bit counter of bits in the buffer in BE format */
                        uint64_t t;
                        t = ctx->total64[0] << 3;
                        t = hton64(t);
                        *(uint64_t *) (&ctx->wbuffer[128 - 8]) = t;
                        t = (ctx->total64[1] << 3) | (ctx->total64[0] >> 61);
                        t = hton64(t);
                        *(uint64_t *) (&ctx->wbuffer[128 - 16]) = t;
                }
                sha512_process_block128(ctx);
                if (pad >= 16)
                        break;
        }

        if (BB_LITTLE_ENDIAN) {
                unsigned i;
                for (i = 0; i < ARRAY_SIZE(ctx->hash); ++i)
                        ctx->hash[i] = hton64(ctx->hash[i]);
        }
        memcpy(resbuf, ctx->hash, sizeof(ctx->hash));
}