/*
 *  RFC 1115/1319 compliant MD2 implementation
 *
 *  Copyright (C) 2006-2007  Christophe Devine
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
/*
 *  The MD2 algorithm was designed by Ron Rivest in 1989.
 *
 *  http://www.ietf.org/rfc/rfc1115.txt
 *  http://www.ietf.org/rfc/rfc1319.txt
 */

#include "xyssl/config.h"

#if defined(XYSSL_MD2_C)

#include "xyssl/md2.h"

#include <string.h>
#include <stdio.h>

static const unsigned char PI_SUBST[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
};

/*
 * MD2 context setup
 */
void md2_starts( md2_context *ctx )
{
    memset( ctx, 0, sizeof( md2_context ) );
}

static void md2_process( md2_context *ctx )
{
    int i, j;
    unsigned char t = 0;

    for( i = 0; i < 16; i++ )
    {
        ctx->state[i + 16] = ctx->buffer[i];
        ctx->state[i + 32] =
            (unsigned char)( ctx->buffer[i] ^ ctx->state[i]);
    }

    for( i = 0; i < 18; i++ )
    {
        for( j = 0; j < 48; j++ )
        {
            ctx->state[j] = (unsigned char)
               ( ctx->state[j] ^ PI_SUBST[t] );
            t  = ctx->state[j];
        }

        t = (unsigned char)( t + i );
    }

    t = ctx->cksum[15];

    for( i = 0; i < 16; i++ )
    {
        ctx->cksum[i] = (unsigned char)
           ( ctx->cksum[i] ^ PI_SUBST[ctx->buffer[i] ^ t] );
        t  = ctx->cksum[i];
    }
}

/*
 * MD2 process buffer
 */
void md2_update( md2_context *ctx, unsigned char *input, int ilen )
{
    int fill;

    while( ilen > 0 )
    {
        if( ctx->left + ilen > 16 )
            fill = 16 - ctx->left;
        else
            fill = ilen;

        memcpy( ctx->buffer + ctx->left, input, fill );

        ctx->left += fill;
        input += fill;
        ilen  -= fill;

        if( ctx->left == 16 )
        {
            ctx->left = 0;
            md2_process( ctx );
        }
    }
}

/*
 * MD2 final digest
 */
void md2_finish( md2_context *ctx, unsigned char output[16] )
{
    int i;
    unsigned char x;

    x = (unsigned char)( 16 - ctx->left );

    for( i = ctx->left; i < 16; i++ )
        ctx->buffer[i] = x;

    md2_process( ctx );

    memcpy( ctx->buffer, ctx->cksum, 16 );
    md2_process( ctx );

    memcpy( output, ctx->state, 16 );
}

/*
 * output = MD2( input buffer )
 */
void md2( unsigned char *input, int ilen, unsigned char output[16] )
{
    md2_context ctx;

    md2_starts( &ctx );
    md2_update( &ctx, input, ilen );
    md2_finish( &ctx, output );

    memset( &ctx, 0, sizeof( md2_context ) );
}

/*
 * output = MD2( file contents )
 */
int md2_file( char *path, unsigned char output[16] )
{
    FILE *f;
    size_t n;
    md2_context ctx;
    unsigned char buf[1024];

    if( ( f = fopen( path, "rb" ) ) == NULL )
        return( 1 );

    md2_starts( &ctx );

    while( ( n = fread( buf, 1, sizeof( buf ), f ) ) > 0 )
        md2_update( &ctx, buf, (int) n );

    md2_finish( &ctx, output );

    memset( &ctx, 0, sizeof( md2_context ) );

    if( ferror( f ) != 0 )
    {
        fclose( f );
        return( 2 );
    }

    fclose( f );
    return( 0 );
}

/*
 * MD2 HMAC context setup
 */
void md2_hmac_starts( md2_context *ctx, unsigned char *key, int keylen )
{
    int i;
    unsigned char sum[16];

    if( keylen > 64 )
    {
        md2( key, keylen, sum );
        keylen = 16;
        key = sum;
    }

    memset( ctx->ipad, 0x36, 64 );
    memset( ctx->opad, 0x5C, 64 );

    for( i = 0; i < keylen; i++ )
    {
        ctx->ipad[i] = (unsigned char)( ctx->ipad[i] ^ key[i] );
        ctx->opad[i] = (unsigned char)( ctx->opad[i] ^ key[i] );
    }

    md2_starts( ctx );
    md2_update( ctx, ctx->ipad, 64 );

    memset( sum, 0, sizeof( sum ) );
}

/*
 * MD2 HMAC process buffer
 */
void md2_hmac_update( md2_context *ctx, unsigned char *input, int ilen )
{
    md2_update( ctx, input, ilen );
}

/*
 * MD2 HMAC final digest
 */
void md2_hmac_finish( md2_context *ctx, unsigned char output[16] )
{
    unsigned char tmpbuf[16];

    md2_finish( ctx, tmpbuf );
    md2_starts( ctx );
    md2_update( ctx, ctx->opad, 64 );
    md2_update( ctx, tmpbuf, 16 );
    md2_finish( ctx, output );

    memset( tmpbuf, 0, sizeof( tmpbuf ) );
}

/*
 * output = HMAC-MD2( hmac key, input buffer )
 */
void md2_hmac( unsigned char *key, int keylen, unsigned char *input, int ilen,
               unsigned char output[16] )
{
    md2_context ctx;

    md2_hmac_starts( &ctx, key, keylen );
    md2_hmac_update( &ctx, input, ilen );
    md2_hmac_finish( &ctx, output );

    memset( &ctx, 0, sizeof( md2_context ) );
}

#if defined(XYSSL_SELF_TEST)

/*
 * RFC 1319 test vectors
 */
static const char md2_test_str[7][81] =
{
    { "" },
    { "a" },
    { "abc" },
    { "message digest" },
    { "abcdefghijklmnopqrstuvwxyz" },
    { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
    { "12345678901234567890123456789012345678901234567890123456789012" \
      "345678901234567890" }
};

static const unsigned char md2_test_sum[7][16] =
{
    { 0x83, 0x50, 0xE5, 0xA3, 0xE2, 0x4C, 0x15, 0x3D,
      0xF2, 0x27, 0x5C, 0x9F, 0x80, 0x69, 0x27, 0x73 },
    { 0x32, 0xEC, 0x01, 0xEC, 0x4A, 0x6D, 0xAC, 0x72,
      0xC0, 0xAB, 0x96, 0xFB, 0x34, 0xC0, 0xB5, 0xD1 },
    { 0xDA, 0x85, 0x3B, 0x0D, 0x3F, 0x88, 0xD9, 0x9B,
      0x30, 0x28, 0x3A, 0x69, 0xE6, 0xDE, 0xD6, 0xBB },
    { 0xAB, 0x4F, 0x49, 0x6B, 0xFB, 0x2A, 0x53, 0x0B,
      0x21, 0x9F, 0xF3, 0x30, 0x31, 0xFE, 0x06, 0xB0 },
    { 0x4E, 0x8D, 0xDF, 0xF3, 0x65, 0x02, 0x92, 0xAB,
      0x5A, 0x41, 0x08, 0xC3, 0xAA, 0x47, 0x94, 0x0B },
    { 0xDA, 0x33, 0xDE, 0xF2, 0xA4, 0x2D, 0xF1, 0x39,
      0x75, 0x35, 0x28, 0x46, 0xC3, 0x03, 0x38, 0xCD },
    { 0xD5, 0x97, 0x6F, 0x79, 0xD8, 0x3D, 0x3A, 0x0D,
      0xC9, 0x80, 0x6C, 0x3C, 0x66, 0xF3, 0xEF, 0xD8 }
};

/*
 * Checkup routine
 */
int md2_self_test( int verbose )
{
    int i;
    unsigned char md2sum[16];

    for( i = 0; i < 7; i++ )
    {
        if( verbose != 0 )
            printf( "  MD2 test #%d: ", i + 1 );

        md2( (unsigned char *) md2_test_str[i],
             strlen( md2_test_str[i] ), md2sum );

        if( memcmp( md2sum, md2_test_sum[i], 16 ) != 0 )
        {
            if( verbose != 0 )
                printf( "failed\n" );

            return( 1 );
        }

        if( verbose != 0 )
            printf( "passed\n" );
    }

    if( verbose != 0 )
        printf( "\n" );

    return( 0 );
}

#endif

#endif