/*
 *  RFC 1321 compliant MD5 implementation
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
/*
 *  The MD5 algorithm was designed by Ron Rivest in 1991.
 *
 *  http://www.ietf.org/rfc/rfc1321.txt
 *
 *  modifier: Honrun
 */
#include <string.h>
#include <stdint.h>
#include "md5.h"

/*
 * 32-bit integer manipulation macros (little endian)
 */
#ifndef GET_UINT32_LE
#define GET_UINT32_LE(n,b,i)                            \
{                                                       \
    (n) = ( (uint32_t) (b)[(i)    ]       )             \
        | ( (uint32_t) (b)[(i) + 1] <<  8 )             \
        | ( (uint32_t) (b)[(i) + 2] << 16 )             \
        | ( (uint32_t) (b)[(i) + 3] << 24 );            \
}
#endif

#ifndef PUT_UINT32_LE
#define PUT_UINT32_LE(n,b,i)                                    \
{                                                               \
    (b)[(i)    ] = (unsigned char) ( ( (n)       ) & 0xFF );    \
    (b)[(i) + 1] = (unsigned char) ( ( (n) >>  8 ) & 0xFF );    \
    (b)[(i) + 2] = (unsigned char) ( ( (n) >> 16 ) & 0xFF );    \
    (b)[(i) + 3] = (unsigned char) ( ( (n) >> 24 ) & 0xFF );    \
}
#endif

void mbedtls_md5_init( mbedtls_md5_context *ctx )
{
    if( ctx == NULL )
        return;

    memset( ctx, 0, sizeof( mbedtls_md5_context ) );
}

void mbedtls_md5_free( mbedtls_md5_context *ctx )
{
    if( ctx == NULL )
        return;

    memset( ctx, 0, sizeof( mbedtls_md5_context ) );
}

void mbedtls_md5_clone( mbedtls_md5_context *dst, const mbedtls_md5_context *src )
{
    if(( dst == NULL ) || ( src == NULL ))
        return;

    *dst = *src;
}

/*
 * MD5 context setup
 */
int32_t mbedtls_md5_starts_ret( mbedtls_md5_context *ctx )
{
    if( ctx == NULL )
        return -1;

    ctx->total[0] = 0;
    ctx->total[1] = 0;

    ctx->state[0] = 0x67452301;
    ctx->state[1] = 0xEFCDAB89;
    ctx->state[2] = 0x98BADCFE;
    ctx->state[3] = 0x10325476;

    return 0;
}

int32_t mbedtls_internal_md5_process( mbedtls_md5_context *ctx, const uint8_t data[64] )
{
    struct
    {
        uint32_t X[16], A, B, C, D;
    } local;

    if( ctx == NULL )
        return -1;

    GET_UINT32_LE( local.X[ 0], data,  0 );
    GET_UINT32_LE( local.X[ 1], data,  4 );
    GET_UINT32_LE( local.X[ 2], data,  8 );
    GET_UINT32_LE( local.X[ 3], data, 12 );
    GET_UINT32_LE( local.X[ 4], data, 16 );
    GET_UINT32_LE( local.X[ 5], data, 20 );
    GET_UINT32_LE( local.X[ 6], data, 24 );
    GET_UINT32_LE( local.X[ 7], data, 28 );
    GET_UINT32_LE( local.X[ 8], data, 32 );
    GET_UINT32_LE( local.X[ 9], data, 36 );
    GET_UINT32_LE( local.X[10], data, 40 );
    GET_UINT32_LE( local.X[11], data, 44 );
    GET_UINT32_LE( local.X[12], data, 48 );
    GET_UINT32_LE( local.X[13], data, 52 );
    GET_UINT32_LE( local.X[14], data, 56 );
    GET_UINT32_LE( local.X[15], data, 60 );

#define S(x,n)                                                          \
    ( ( (x) << (n) ) | ( ( (x) & 0xFFFFFFFF) >> ( 32 - (n) ) ) )

#define P(a,b,c,d,k,s,t)                                                \
    do                                                                  \
    {                                                                   \
        (a) += F((b),(c),(d)) + local.X[(k)] + (t);                     \
        (a) = S((a),(s)) + (b);                                         \
    } while( 0 )

    local.A = ctx->state[0];
    local.B = ctx->state[1];
    local.C = ctx->state[2];
    local.D = ctx->state[3];

#define F(x,y,z) ((z) ^ ((x) & ((y) ^ (z))))

    P( local.A, local.B, local.C, local.D,  0,  7, 0xD76AA478 );
    P( local.D, local.A, local.B, local.C,  1, 12, 0xE8C7B756 );
    P( local.C, local.D, local.A, local.B,  2, 17, 0x242070DB );
    P( local.B, local.C, local.D, local.A,  3, 22, 0xC1BDCEEE );
    P( local.A, local.B, local.C, local.D,  4,  7, 0xF57C0FAF );
    P( local.D, local.A, local.B, local.C,  5, 12, 0x4787C62A );
    P( local.C, local.D, local.A, local.B,  6, 17, 0xA8304613 );
    P( local.B, local.C, local.D, local.A,  7, 22, 0xFD469501 );
    P( local.A, local.B, local.C, local.D,  8,  7, 0x698098D8 );
    P( local.D, local.A, local.B, local.C,  9, 12, 0x8B44F7AF );
    P( local.C, local.D, local.A, local.B, 10, 17, 0xFFFF5BB1 );
    P( local.B, local.C, local.D, local.A, 11, 22, 0x895CD7BE );
    P( local.A, local.B, local.C, local.D, 12,  7, 0x6B901122 );
    P( local.D, local.A, local.B, local.C, 13, 12, 0xFD987193 );
    P( local.C, local.D, local.A, local.B, 14, 17, 0xA679438E );
    P( local.B, local.C, local.D, local.A, 15, 22, 0x49B40821 );

#undef F

#define F(x,y,z) ((y) ^ ((z) & ((x) ^ (y))))

    P( local.A, local.B, local.C, local.D,  1,  5, 0xF61E2562 );
    P( local.D, local.A, local.B, local.C,  6,  9, 0xC040B340 );
    P( local.C, local.D, local.A, local.B, 11, 14, 0x265E5A51 );
    P( local.B, local.C, local.D, local.A,  0, 20, 0xE9B6C7AA );
    P( local.A, local.B, local.C, local.D,  5,  5, 0xD62F105D );
    P( local.D, local.A, local.B, local.C, 10,  9, 0x02441453 );
    P( local.C, local.D, local.A, local.B, 15, 14, 0xD8A1E681 );
    P( local.B, local.C, local.D, local.A,  4, 20, 0xE7D3FBC8 );
    P( local.A, local.B, local.C, local.D,  9,  5, 0x21E1CDE6 );
    P( local.D, local.A, local.B, local.C, 14,  9, 0xC33707D6 );
    P( local.C, local.D, local.A, local.B,  3, 14, 0xF4D50D87 );
    P( local.B, local.C, local.D, local.A,  8, 20, 0x455A14ED );
    P( local.A, local.B, local.C, local.D, 13,  5, 0xA9E3E905 );
    P( local.D, local.A, local.B, local.C,  2,  9, 0xFCEFA3F8 );
    P( local.C, local.D, local.A, local.B,  7, 14, 0x676F02D9 );
    P( local.B, local.C, local.D, local.A, 12, 20, 0x8D2A4C8A );

#undef F

#define F(x,y,z) ((x) ^ (y) ^ (z))

    P( local.A, local.B, local.C, local.D,  5,  4, 0xFFFA3942 );
    P( local.D, local.A, local.B, local.C,  8, 11, 0x8771F681 );
    P( local.C, local.D, local.A, local.B, 11, 16, 0x6D9D6122 );
    P( local.B, local.C, local.D, local.A, 14, 23, 0xFDE5380C );
    P( local.A, local.B, local.C, local.D,  1,  4, 0xA4BEEA44 );
    P( local.D, local.A, local.B, local.C,  4, 11, 0x4BDECFA9 );
    P( local.C, local.D, local.A, local.B,  7, 16, 0xF6BB4B60 );
    P( local.B, local.C, local.D, local.A, 10, 23, 0xBEBFBC70 );
    P( local.A, local.B, local.C, local.D, 13,  4, 0x289B7EC6 );
    P( local.D, local.A, local.B, local.C,  0, 11, 0xEAA127FA );
    P( local.C, local.D, local.A, local.B,  3, 16, 0xD4EF3085 );
    P( local.B, local.C, local.D, local.A,  6, 23, 0x04881D05 );
    P( local.A, local.B, local.C, local.D,  9,  4, 0xD9D4D039 );
    P( local.D, local.A, local.B, local.C, 12, 11, 0xE6DB99E5 );
    P( local.C, local.D, local.A, local.B, 15, 16, 0x1FA27CF8 );
    P( local.B, local.C, local.D, local.A,  2, 23, 0xC4AC5665 );

#undef F

#define F(x,y,z) ((y) ^ ((x) | ~(z)))

    P( local.A, local.B, local.C, local.D,  0,  6, 0xF4292244 );
    P( local.D, local.A, local.B, local.C,  7, 10, 0x432AFF97 );
    P( local.C, local.D, local.A, local.B, 14, 15, 0xAB9423A7 );
    P( local.B, local.C, local.D, local.A,  5, 21, 0xFC93A039 );
    P( local.A, local.B, local.C, local.D, 12,  6, 0x655B59C3 );
    P( local.D, local.A, local.B, local.C,  3, 10, 0x8F0CCC92 );
    P( local.C, local.D, local.A, local.B, 10, 15, 0xFFEFF47D );
    P( local.B, local.C, local.D, local.A,  1, 21, 0x85845DD1 );
    P( local.A, local.B, local.C, local.D,  8,  6, 0x6FA87E4F );
    P( local.D, local.A, local.B, local.C, 15, 10, 0xFE2CE6E0 );
    P( local.C, local.D, local.A, local.B,  6, 15, 0xA3014314 );
    P( local.B, local.C, local.D, local.A, 13, 21, 0x4E0811A1 );
    P( local.A, local.B, local.C, local.D,  4,  6, 0xF7537E82 );
    P( local.D, local.A, local.B, local.C, 11, 10, 0xBD3AF235 );
    P( local.C, local.D, local.A, local.B,  2, 15, 0x2AD7D2BB );
    P( local.B, local.C, local.D, local.A,  9, 21, 0xEB86D391 );

#undef F

    ctx->state[0] += local.A;
    ctx->state[1] += local.B;
    ctx->state[2] += local.C;
    ctx->state[3] += local.D;

    /* Zeroise variables to clear sensitive data from memory. */
    memset( &local, 0, sizeof( local ) );

    return 0;
}

/*
 * MD5 process buffer
 */
int32_t mbedtls_md5_update_ret( mbedtls_md5_context *ctx, const uint8_t *input, int32_t ilen )
{
    int32_t fill;
    uint32_t left;

    if(( ctx == NULL ) || ( input == NULL ))
        return -1;

    if( ilen == 0 )
        return -2;

    left = ctx->total[0] & 0x3F;
    fill = 64 - left;

    ctx->total[0] += (uint32_t) ilen;
    ctx->total[0] &= 0xFFFFFFFF;

    if( ctx->total[0] < (uint32_t) ilen )
        ctx->total[1]++;

    if( left && ilen >= fill )
    {
        memcpy( (void *) (ctx->buffer + left), input, fill );
        if( ( mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
            return -3;

        input += fill;
        ilen  -= fill;
        left = 0;
    }

    while( ilen >= 64 )
    {
        if( ( mbedtls_internal_md5_process( ctx, input ) ) != 0 )
            return -4;

        input += 64;
        ilen  -= 64;
    }

    if( ilen > 0 )
    {
        memcpy( (void *) (ctx->buffer + left), input, ilen );
    }

    return 0;
}

/*
 * MD5 final digest
 */
int32_t mbedtls_md5_finish_ret( mbedtls_md5_context *ctx, uint8_t output[16] )
{
    uint32_t used, high, low;

    if( ctx == NULL )
        return -1;

    /*
     * Add padding: 0x80 then 0x00 until 8 bytes remain for the length
     */
    used = ctx->total[0] & 0x3F;

    ctx->buffer[used++] = 0x80;

    if( used <= 56 )
    {
        /* Enough room for padding + length in current block */
        memset( ctx->buffer + used, 0, 56 - used );
    }
    else
    {
        /* We'll need an extra block */
        memset( ctx->buffer + used, 0, 64 - used );

        if( ( mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
            return -2;

        memset( ctx->buffer, 0, 56 );
    }

    /*
     * Add message length
     */
    high = ( ctx->total[0] >> 29 )
         | ( ctx->total[1] <<  3 );
    low  = ( ctx->total[0] <<  3 );

    PUT_UINT32_LE( low,  ctx->buffer, 56 );
    PUT_UINT32_LE( high, ctx->buffer, 60 );

    if( ( mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
        return -3;

    /*
     * Output final state
     */
    PUT_UINT32_LE( ctx->state[0], output,  0 );
    PUT_UINT32_LE( ctx->state[1], output,  4 );
    PUT_UINT32_LE( ctx->state[2], output,  8 );
    PUT_UINT32_LE( ctx->state[3], output, 12 );

    return 0;
}

/*
 * output = MD5( input buffer )
 */
int32_t mbedtls_md5_ret( const uint8_t *input, int32_t ilen, uint8_t output[16] )
{
    mbedtls_md5_context ctx = {0};

    if(( input == NULL ) || ( output == NULL ))
        return -1;

    mbedtls_md5_init( &ctx );

    if( ( mbedtls_md5_starts_ret( &ctx ) ) != 0 )
        return -2;

    if( ( mbedtls_md5_update_ret( &ctx, input, ilen ) ) != 0 )
        return -3;

    if( ( mbedtls_md5_finish_ret( &ctx, output ) ) != 0 )
        return -4;

    return 0;
}