/* Copyright Gisle Ass, Peter C. Gutmann, Bruce Schneier
 * Copyright 2004 Shevek <srs@anarres.org>
 * Copyright 2012-2022 Timo Röhling <timo@gaussglocke.de>
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * This file has been copied from libsrs2. Original copyright follows:
 */

/* NIST Secure Hash Algorithm */
/* Borrowed from SHA1.xs by Gisle Ass */
/* heavily modified by Uwe Hollerbach <uh@alumni.caltech edu> */
/* from Peter C. Gutmann's implementation as found in */
/* Applied Cryptography by Bruce Schneier */
/* Further modifications to include the "UNRAVEL" stuff, below */
/* HMAC functions by Shevek <srs@anarres.org> for inclusion in
 * libsrs2, under GPL-2 or BSD license. Combine this lot in any way
 * you think will stand up in court. I hope my intent is clear. */

/* This code is in the public domain */

#include "sha1.h"

#include "postsrsd_build_config.h"

#include <string.h> /* memcpy, strcpy, memset */

#ifdef SIZEOF_UNSIGNED_LONG
#    if SIZEOF_UNSIGNED_LONG < 4
#        error "SHA1 requires an unsigned long of at least 32 bits"
#    endif
#endif

#if SIZEOF_UNSIGNED_LONG == 4
#    ifdef HAVE_BIG_ENDIAN
#        define BYTEORDER 0x4321
#    else
#        define BYTEORDER 0x1234
#    endif
#elif SIZEOF_UNSIGNED_LONG == 8
#    ifdef HAVE_BIG_ENDIAN
#        define BYTEORDER 0x87654321
#    else
#        define BYTEORDER 0x12345678
#    endif
#else
#    error "SHA1 requires an unsigned long of either 4 or 8 bytes"
#endif

/* UNRAVEL should be fastest & biggest */
/* UNROLL_LOOPS should be just as big, but slightly slower */
/* both undefined should be smallest and slowest */

#define SHA_VERSION 1
#define UNRAVEL
/* #define UNROLL_LOOPS */

/* SHA f()-functions */
#define f1(x, y, z) ((x & y) | (~x & z))
#define f2(x, y, z) (x ^ y ^ z)
#define f3(x, y, z) ((x & y) | (x & z) | (y & z))
#define f4(x, y, z) (x ^ y ^ z)

/* SHA constants */
#define CONST1 0x5a827999L
#define CONST2 0x6ed9eba1L
#define CONST3 0x8f1bbcdcL
#define CONST4 0xca62c1d6L

/* truncate to 32 bits -- should be a null op on 32-bit machines */
#define T32(x) ((x) & 0xffffffffL)

/* 32-bit rotate */
#define R32(x, n) T32(((x << n) | (x >> (32 - n))))

/* the generic case, for when the overall rotation is not unraveled */
#define FG(n)                                                  \
    T = T32(R32(A, 5) + f##n(B, C, D) + E + *WP++ + CONST##n); \
    E = D;                                                     \
    D = C;                                                     \
    C = R32(B, 30);                                            \
    B = A;                                                     \
    A = T

/* specific cases, for when the overall rotation is unraveled */
#define FA(n)                                                  \
    T = T32(R32(A, 5) + f##n(B, C, D) + E + *WP++ + CONST##n); \
    B = R32(B, 30)

#define FB(n)                                                  \
    E = T32(R32(T, 5) + f##n(A, B, C) + D + *WP++ + CONST##n); \
    A = R32(A, 30)

#define FC(n)                                                  \
    D = T32(R32(E, 5) + f##n(T, A, B) + C + *WP++ + CONST##n); \
    T = R32(T, 30)

#define FD(n)                                                  \
    C = T32(R32(D, 5) + f##n(E, T, A) + B + *WP++ + CONST##n); \
    E = R32(E, 30)

#define FE(n)                                                  \
    B = T32(R32(C, 5) + f##n(D, E, T) + A + *WP++ + CONST##n); \
    D = R32(D, 30)

#define FT(n)                                                  \
    A = T32(R32(B, 5) + f##n(C, D, E) + T + *WP++ + CONST##n); \
    C = R32(C, 30)

static void sha_transform(SHA_INFO* sha_info)
{
    int i;
    sha_byte* dp;
    ULONG T, A, B, C, D, E, W[80], *WP;

    dp = sha_info->data;

/*
the following makes sure that at least one code block below is
traversed or an error is reported, without the necessity for nested
preprocessor if/else/endif blocks, which are a great pain in the
nether regions of the anatomy...
*/
#undef SWAP_DONE

#if BYTEORDER == 0x1234
#    define SWAP_DONE
    /* assert(sizeof(ULONG) == 4); */
    for (i = 0; i < 16; ++i)
    {
        T = *((ULONG*)dp);
        dp += 4;
        W[i] = ((T << 24) & 0xff000000) | ((T << 8) & 0x00ff0000)
               | ((T >> 8) & 0x0000ff00) | ((T >> 24) & 0x000000ff);
    }
#endif

#if BYTEORDER == 0x4321
#    define SWAP_DONE
    /* assert(sizeof(ULONG) == 4); */
    for (i = 0; i < 16; ++i)
    {
        T = *((ULONG*)dp);
        dp += 4;
        W[i] = T32(T);
    }
#endif

#if BYTEORDER == 0x12345678
#    define SWAP_DONE
    /* assert(sizeof(ULONG) == 8); */
    for (i = 0; i < 16; i += 2)
    {
        T = *((ULONG*)dp);
        dp += 8;
        W[i] = ((T << 24) & 0xff000000) | ((T << 8) & 0x00ff0000)
               | ((T >> 8) & 0x0000ff00) | ((T >> 24) & 0x000000ff);
        T >>= 32;
        W[i + 1] = ((T << 24) & 0xff000000) | ((T << 8) & 0x00ff0000)
                   | ((T >> 8) & 0x0000ff00) | ((T >> 24) & 0x000000ff);
    }
#endif

#if BYTEORDER == 0x87654321
#    define SWAP_DONE
    /* assert(sizeof(ULONG) == 8); */
    for (i = 0; i < 16; i += 2)
    {
        T = *((ULONG*)dp);
        dp += 8;
        W[i] = T32(T >> 32);
        W[i + 1] = T32(T);
    }
#endif

#ifndef SWAP_DONE
#    error Unknown byte order -- you need to add code here
#endif

    for (i = 16; i < 80; ++i)
    {
        W[i] = W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16];
#if (SHA_VERSION == 1)
        W[i] = R32(W[i], 1);
#endif
    }
    A = sha_info->digest[0];
    B = sha_info->digest[1];
    C = sha_info->digest[2];
    D = sha_info->digest[3];
    E = sha_info->digest[4];
    WP = W;
#ifdef UNRAVEL
    /* clang-format off */
    FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1); FC(1); FD(1);
    FE(1); FT(1); FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1);
    FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2); FE(2); FT(2);
    FA(2); FB(2); FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2);
    FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3); FA(3); FB(3);
    FC(3); FD(3); FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3);
    FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4); FC(4); FD(4);
    FE(4); FT(4); FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4);
    /* clang-format on */
    sha_info->digest[0] = T32(sha_info->digest[0] + E);
    sha_info->digest[1] = T32(sha_info->digest[1] + T);
    sha_info->digest[2] = T32(sha_info->digest[2] + A);
    sha_info->digest[3] = T32(sha_info->digest[3] + B);
    sha_info->digest[4] = T32(sha_info->digest[4] + C);
#else
#    ifdef UNROLL_LOOPS
    /* clang-format off */
    FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);
    FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);
    FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);
    FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);
    FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);
    FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);
    FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);
    FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);
    /* clang-format on */
#    else
    for (i = 0; i < 20; ++i)
    {
        FG(1);
    }
    for (i = 20; i < 40; ++i)
    {
        FG(2);
    }
    for (i = 40; i < 60; ++i)
    {
        FG(3);
    }
    for (i = 60; i < 80; ++i)
    {
        FG(4);
    }
#    endif
    sha_info->digest[0] = T32(sha_info->digest[0] + A);
    sha_info->digest[1] = T32(sha_info->digest[1] + B);
    sha_info->digest[2] = T32(sha_info->digest[2] + C);
    sha_info->digest[3] = T32(sha_info->digest[3] + D);
    sha_info->digest[4] = T32(sha_info->digest[4] + E);
#endif
}

/* initialize the SHA digest */

static void sha_init(SHA_INFO* sha_info)
{
    sha_info->digest[0] = 0x67452301L;
    sha_info->digest[1] = 0xefcdab89L;
    sha_info->digest[2] = 0x98badcfeL;
    sha_info->digest[3] = 0x10325476L;
    sha_info->digest[4] = 0xc3d2e1f0L;
    sha_info->count_lo = 0L;
    sha_info->count_hi = 0L;
    sha_info->local = 0;
}

/* update the SHA digest */

static void sha_update(SHA_INFO* sha_info, const sha_byte* buffer, int count)
{
    int i;
    ULONG clo;

    clo = T32(sha_info->count_lo + ((ULONG)count << 3));
    if (clo < sha_info->count_lo)
    {
        ++sha_info->count_hi;
    }
    sha_info->count_lo = clo;
    sha_info->count_hi += (ULONG)count >> 29;
    if (sha_info->local)
    {
        i = SHA_BLOCKSIZE - sha_info->local;
        if (i > count)
        {
            i = count;
        }
        memcpy(((sha_byte*)sha_info->data) + sha_info->local, buffer, i);
        count -= i;
        buffer += i;
        sha_info->local += i;
        if (sha_info->local == SHA_BLOCKSIZE)
        {
            sha_transform(sha_info);
        }
        else
        {
            return;
        }
    }
    while (count >= SHA_BLOCKSIZE)
    {
        memcpy(sha_info->data, buffer, SHA_BLOCKSIZE);
        buffer += SHA_BLOCKSIZE;
        count -= SHA_BLOCKSIZE;
        sha_transform(sha_info);
    }
    memcpy(sha_info->data, buffer, count);
    sha_info->local = count;
}

static void sha_transform_and_copy(unsigned char digest[20], SHA_INFO* sha_info)
{
    sha_transform(sha_info);
    digest[0] = (unsigned char)((sha_info->digest[0] >> 24) & 0xff);
    digest[1] = (unsigned char)((sha_info->digest[0] >> 16) & 0xff);
    digest[2] = (unsigned char)((sha_info->digest[0] >> 8) & 0xff);
    digest[3] = (unsigned char)((sha_info->digest[0]) & 0xff);
    digest[4] = (unsigned char)((sha_info->digest[1] >> 24) & 0xff);
    digest[5] = (unsigned char)((sha_info->digest[1] >> 16) & 0xff);
    digest[6] = (unsigned char)((sha_info->digest[1] >> 8) & 0xff);
    digest[7] = (unsigned char)((sha_info->digest[1]) & 0xff);
    digest[8] = (unsigned char)((sha_info->digest[2] >> 24) & 0xff);
    digest[9] = (unsigned char)((sha_info->digest[2] >> 16) & 0xff);
    digest[10] = (unsigned char)((sha_info->digest[2] >> 8) & 0xff);
    digest[11] = (unsigned char)((sha_info->digest[2]) & 0xff);
    digest[12] = (unsigned char)((sha_info->digest[3] >> 24) & 0xff);
    digest[13] = (unsigned char)((sha_info->digest[3] >> 16) & 0xff);
    digest[14] = (unsigned char)((sha_info->digest[3] >> 8) & 0xff);
    digest[15] = (unsigned char)((sha_info->digest[3]) & 0xff);
    digest[16] = (unsigned char)((sha_info->digest[4] >> 24) & 0xff);
    digest[17] = (unsigned char)((sha_info->digest[4] >> 16) & 0xff);
    digest[18] = (unsigned char)((sha_info->digest[4] >> 8) & 0xff);
    digest[19] = (unsigned char)((sha_info->digest[4]) & 0xff);
}

/* finish computing the SHA digest */
static void sha_final(unsigned char digest[20], SHA_INFO* sha_info)
{
    int count;
    ULONG lo_bit_count, hi_bit_count;

    lo_bit_count = sha_info->count_lo;
    hi_bit_count = sha_info->count_hi;
    count = (int)((lo_bit_count >> 3) & 0x3f);
    ((sha_byte*)sha_info->data)[count++] = 0x80;
    if (count > SHA_BLOCKSIZE - 8)
    {
        memset(((sha_byte*)sha_info->data) + count, 0, SHA_BLOCKSIZE - count);
        sha_transform(sha_info);
        memset((sha_byte*)sha_info->data, 0, SHA_BLOCKSIZE - 8);
    }
    else
    {
        memset(((sha_byte*)sha_info->data) + count, 0,
               SHA_BLOCKSIZE - 8 - count);
    }
    sha_info->data[56] = (hi_bit_count >> 24) & 0xff;
    sha_info->data[57] = (hi_bit_count >> 16) & 0xff;
    sha_info->data[58] = (hi_bit_count >> 8) & 0xff;
    sha_info->data[59] = (hi_bit_count >> 0) & 0xff;
    sha_info->data[60] = (lo_bit_count >> 24) & 0xff;
    sha_info->data[61] = (lo_bit_count >> 16) & 0xff;
    sha_info->data[62] = (lo_bit_count >> 8) & 0xff;
    sha_info->data[63] = (lo_bit_count >> 0) & 0xff;
    sha_transform_and_copy(digest, sha_info);
}

/********************************************************************/
/*
    SHA_INFO ctx;
    unsigned char *data;
    STRLEN len;
    unsigned char digeststr[20];

    sha_init(&ctx);

    for (i = 0; i < items; i++) {
            data = (unsigned char *)(SvPVbyte(ST(i), len));
            sha_update(&ctx, data, len);
    }
    sha_final(digeststr, &ctx);
*/

void sha_digest(char* out, const char* data, unsigned len)
{
    SHA_INFO ctx;
    sha_init(&ctx);
    sha_update(&ctx, (const sha_byte*)data, len);
    sha_final((sha_byte*)out, &ctx);
}

void srs_hmac_init(srs_hmac_ctx_t* ctx, char* secret, unsigned len)
{
    char sbuf[SHA_BLOCKSIZE];
    unsigned i;

    if (len > SHA_BLOCKSIZE)
    {
        sha_digest(sbuf, secret, len);
        secret = sbuf;
        len = SHA_DIGESTSIZE;
    }

    memset(ctx->ipad, 0x36, SHA_BLOCKSIZE);
    memset(ctx->opad, 0x5c, SHA_BLOCKSIZE);
    for (i = 0; i < len; i++)
    {
        ctx->ipad[i] ^= secret[i];
        ctx->opad[i] ^= secret[i];
    }

    memset(sbuf, 0, SHA_BLOCKSIZE);

    sha_init(&ctx->sctx);
    sha_update(&ctx->sctx, (sha_byte*)ctx->ipad, SHA_BLOCKSIZE);
}

void srs_hmac_update(srs_hmac_ctx_t* ctx, char* data, unsigned len)
{
    sha_update(&ctx->sctx, (sha_byte*)data, len);
}

void srs_hmac_fini(srs_hmac_ctx_t* ctx, char* out)
{
    sha_byte buf[SHA_DIGESTSIZE + 1];

    sha_final(buf, &ctx->sctx);
    sha_init(&ctx->sctx);
    sha_update(&ctx->sctx, (sha_byte*)ctx->opad, SHA_BLOCKSIZE);
    sha_update(&ctx->sctx, buf, SHA_DIGESTSIZE);
    sha_final((sha_byte*)out, &ctx->sctx);
}
