/*
 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/*
 * MD2 low level APIs are deprecated for public use, but still ok for
 * internal use.
 */
#include "internal/deprecated.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/md2.h>
#include <openssl/opensslv.h>
#include <openssl/crypto.h>

/*
 * Implemented from RFC1319 The MD2 Message-Digest Algorithm
 */

#define UCHAR unsigned char

static void md2_block(MD2_CTX *c, const unsigned char *d);
/*
 * The magic S table - I have converted it to hex since it is basically just
 * a random byte string.
 */
static const MD2_INT S[256] = {
    0x29,
    0x2E,
    0x43,
    0xC9,
    0xA2,
    0xD8,
    0x7C,
    0x01,
    0x3D,
    0x36,
    0x54,
    0xA1,
    0xEC,
    0xF0,
    0x06,
    0x13,
    0x62,
    0xA7,
    0x05,
    0xF3,
    0xC0,
    0xC7,
    0x73,
    0x8C,
    0x98,
    0x93,
    0x2B,
    0xD9,
    0xBC,
    0x4C,
    0x82,
    0xCA,
    0x1E,
    0x9B,
    0x57,
    0x3C,
    0xFD,
    0xD4,
    0xE0,
    0x16,
    0x67,
    0x42,
    0x6F,
    0x18,
    0x8A,
    0x17,
    0xE5,
    0x12,
    0xBE,
    0x4E,
    0xC4,
    0xD6,
    0xDA,
    0x9E,
    0xDE,
    0x49,
    0xA0,
    0xFB,
    0xF5,
    0x8E,
    0xBB,
    0x2F,
    0xEE,
    0x7A,
    0xA9,
    0x68,
    0x79,
    0x91,
    0x15,
    0xB2,
    0x07,
    0x3F,
    0x94,
    0xC2,
    0x10,
    0x89,
    0x0B,
    0x22,
    0x5F,
    0x21,
    0x80,
    0x7F,
    0x5D,
    0x9A,
    0x5A,
    0x90,
    0x32,
    0x27,
    0x35,
    0x3E,
    0xCC,
    0xE7,
    0xBF,
    0xF7,
    0x97,
    0x03,
    0xFF,
    0x19,
    0x30,
    0xB3,
    0x48,
    0xA5,
    0xB5,
    0xD1,
    0xD7,
    0x5E,
    0x92,
    0x2A,
    0xAC,
    0x56,
    0xAA,
    0xC6,
    0x4F,
    0xB8,
    0x38,
    0xD2,
    0x96,
    0xA4,
    0x7D,
    0xB6,
    0x76,
    0xFC,
    0x6B,
    0xE2,
    0x9C,
    0x74,
    0x04,
    0xF1,
    0x45,
    0x9D,
    0x70,
    0x59,
    0x64,
    0x71,
    0x87,
    0x20,
    0x86,
    0x5B,
    0xCF,
    0x65,
    0xE6,
    0x2D,
    0xA8,
    0x02,
    0x1B,
    0x60,
    0x25,
    0xAD,
    0xAE,
    0xB0,
    0xB9,
    0xF6,
    0x1C,
    0x46,
    0x61,
    0x69,
    0x34,
    0x40,
    0x7E,
    0x0F,
    0x55,
    0x47,
    0xA3,
    0x23,
    0xDD,
    0x51,
    0xAF,
    0x3A,
    0xC3,
    0x5C,
    0xF9,
    0xCE,
    0xBA,
    0xC5,
    0xEA,
    0x26,
    0x2C,
    0x53,
    0x0D,
    0x6E,
    0x85,
    0x28,
    0x84,
    0x09,
    0xD3,
    0xDF,
    0xCD,
    0xF4,
    0x41,
    0x81,
    0x4D,
    0x52,
    0x6A,
    0xDC,
    0x37,
    0xC8,
    0x6C,
    0xC1,
    0xAB,
    0xFA,
    0x24,
    0xE1,
    0x7B,
    0x08,
    0x0C,
    0xBD,
    0xB1,
    0x4A,
    0x78,
    0x88,
    0x95,
    0x8B,
    0xE3,
    0x63,
    0xE8,
    0x6D,
    0xE9,
    0xCB,
    0xD5,
    0xFE,
    0x3B,
    0x00,
    0x1D,
    0x39,
    0xF2,
    0xEF,
    0xB7,
    0x0E,
    0x66,
    0x58,
    0xD0,
    0xE4,
    0xA6,
    0x77,
    0x72,
    0xF8,
    0xEB,
    0x75,
    0x4B,
    0x0A,
    0x31,
    0x44,
    0x50,
    0xB4,
    0x8F,
    0xED,
    0x1F,
    0x1A,
    0xDB,
    0x99,
    0x8D,
    0x33,
    0x9F,
    0x11,
    0x83,
    0x14,
};

const char *MD2_options(void)
{
    if (sizeof(MD2_INT) == 1)
        return "md2(char)";
    else
        return "md2(int)";
}

int MD2_Init(MD2_CTX *c)
{
    c->num = 0;
    memset(c->state, 0, sizeof(c->state));
    memset(c->cksm, 0, sizeof(c->cksm));
    memset(c->data, 0, sizeof(c->data));
    return 1;
}

int MD2_Update(MD2_CTX *c, const unsigned char *data, size_t len)
{
    register UCHAR *p;

    if (len == 0)
        return 1;

    p = c->data;
    if (c->num != 0) {
        if ((c->num + len) >= MD2_BLOCK) {
            memcpy(&(p[c->num]), data, MD2_BLOCK - c->num);
            md2_block(c, c->data);
            data += (MD2_BLOCK - c->num);
            len -= (MD2_BLOCK - c->num);
            c->num = 0;
            /* drop through and do the rest */
        } else {
            memcpy(&(p[c->num]), data, len);
            /* data+=len; */
            c->num += (int)len;
            return 1;
        }
    }
    /*
     * we now can process the input data in blocks of MD2_BLOCK chars and
     * save the leftovers to c->data.
     */
    while (len >= MD2_BLOCK) {
        md2_block(c, data);
        data += MD2_BLOCK;
        len -= MD2_BLOCK;
    }
    memcpy(p, data, len);
    c->num = (int)len;
    return 1;
}

static void md2_block(MD2_CTX *c, const unsigned char *d)
{
    register MD2_INT t, *sp1, *sp2;
    register int i, j;
    MD2_INT state[48];

    sp1 = c->state;
    sp2 = c->cksm;
    j = sp2[MD2_BLOCK - 1];
    for (i = 0; i < 16; i++) {
        state[i] = sp1[i];
        state[i + 16] = t = d[i];
        state[i + 32] = (t ^ sp1[i]);
        j = sp2[i] ^= S[t ^ j];
    }
    t = 0;
    for (i = 0; i < 18; i++) {
        for (j = 0; j < 48; j += 8) {
            t = state[j + 0] ^= S[t];
            t = state[j + 1] ^= S[t];
            t = state[j + 2] ^= S[t];
            t = state[j + 3] ^= S[t];
            t = state[j + 4] ^= S[t];
            t = state[j + 5] ^= S[t];
            t = state[j + 6] ^= S[t];
            t = state[j + 7] ^= S[t];
        }
        t = (t + i) & 0xff;
    }
    memcpy(sp1, state, 16 * sizeof(MD2_INT));
    OPENSSL_cleanse(state, 48 * sizeof(MD2_INT));
}

int MD2_Final(unsigned char *md, MD2_CTX *c)
{
    int i, v;
    register UCHAR *cp;
    register MD2_INT *p1, *p2;

    cp = c->data;
    p1 = c->state;
    p2 = c->cksm;
    v = MD2_BLOCK - c->num;
    for (i = c->num; i < MD2_BLOCK; i++)
        cp[i] = (UCHAR)v;

    md2_block(c, cp);

    for (i = 0; i < MD2_BLOCK; i++)
        cp[i] = (UCHAR)p2[i];
    md2_block(c, cp);

    for (i = 0; i < 16; i++)
        md[i] = (UCHAR)(p1[i] & 0xff);
    OPENSSL_cleanse(c, sizeof(*c));
    return 1;
}