// clang-format off

// This file implements a class for computation of MD5 checksums.

// It is derived from the reference algorithm for MD5 as given in

// RFC 1321.  The original copyright notice is as follows:

//

/////////////////////////////////////////////////////////////////////////

//

// Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All

// rights reserved.

//

// License to copy and use this software is granted provided that it

// is identified as the "RSA Data Security, Inc. MD5 Message-Digest

// Algorithm" in all material mentioning or referencing this software

// or this function.

//

// License is also granted to make and use derivative works provided

// that such works are identified as "derived from the RSA Data

// Security, Inc. MD5 Message-Digest Algorithm" in all material

// mentioning or referencing the derived work.

//

// RSA Data Security, Inc. makes no representations concerning either

// the merchantability of this software or the suitability of this

// software for any particular purpose. It is provided "as is"

// without express or implied warranty of any kind.

//

// These notices must be retained in any copies of any part of this

// documentation and/or software.

//

/////////////////////////////////////////////////////////////////////////

#include <qpdf/MD5_native.hh>

#include <qpdf/QUtil.hh>

#include <qpdf/QIntC.hh>

#include <stdio.h>

#include <memory.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

int const S11 = 7;

int const S12 = 12;

int const S13 = 17;

int const S14 = 22;

int const S21 = 5;

int const S22 = 9;

int const S23 = 14;

int const S24 = 20;

int const S31 = 4;

int const S32 = 11;

int const S33 = 16;

int const S34 = 23;

int const S41 = 6;

int const S42 = 10;

int const S43 = 15;

int const S44 = 21;

static unsigned char PADDING[64] = {

  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

};

// F, G, H and I are basic MD5 functions.

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

#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))

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

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

// ROTATE_LEFT rotates x left n bits.

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

// FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.

// Rotation is separate from addition to prevent recomputation.

#define FF(a, b, c, d, x, s, ac) { \

 (a) += F ((b), (c), (d)) + (x) + static_cast<uint32_t>(ac); \

 (a) = ROTATE_LEFT ((a), (s)); \

 (a) += (b); \

  }

#define GG(a, b, c, d, x, s, ac) { \

 (a) += G ((b), (c), (d)) + (x) + static_cast<uint32_t>(ac); \

 (a) = ROTATE_LEFT ((a), (s)); \

 (a) += (b); \

  }

#define HH(a, b, c, d, x, s, ac) { \

 (a) += H ((b), (c), (d)) + (x) + static_cast<uint32_t>(ac); \

 (a) = ROTATE_LEFT ((a), (s)); \

 (a) += (b); \

  }

#define II(a, b, c, d, x, s, ac) { \

 (a) += I ((b), (c), (d)) + (x) + static_cast<uint32_t>(ac); \

 (a) = ROTATE_LEFT ((a), (s)); \

 (a) += (b); \

  }

MD5_native::MD5_native()

{

    init();

}

// MD5 initialization. Begins an MD5 operation, writing a new context.

void MD5_native::init()

{

    count[0] = count[1] = 0;

    // Load magic initialization constants.

    state[0] = 0x67452301;

    state[1] = 0xefcdab89;

    state[2] = 0x98badcfe;

    state[3] = 0x10325476;

    finalized = false;

    memset(digest_val, 0, sizeof(digest_val));

}

// MD5 block update operation. Continues an MD5 message-digest

// operation, processing another message block, and updating the

// context.

void MD5_native::update(unsigned char *input,

                 size_t inputLen)

{

    unsigned int i, index, partLen;

    // Compute number of bytes mod 64

    index = static_cast<unsigned int>((count[0] >> 3) & 0x3f);

    // Update number of bits

    if ((count[0] += (static_cast<uint32_t>(inputLen) << 3)) <

        (static_cast<uint32_t>(inputLen) << 3))

        count[1]++;

    count[1] += (static_cast<uint32_t>(inputLen) >> 29);

    partLen = 64 - index;

    // Transform as many times as possible.

    if (inputLen >= partLen) {

        memcpy(&buffer[index], input, partLen);

        transform(state, buffer);

        for (i = partLen; i + 63 < inputLen; i += 64)

            transform(state, &input[i]);

        index = 0;

    }

    else

        i = 0;

    // Buffer remaining input

    memcpy(&buffer[index], &input[i], inputLen-i);

}

// MD5 finalization. Ends an MD5 message-digest operation, writing the

// the message digest and zeroizing the context.

void MD5_native::finalize()

{

    if (finalized)

    {

        return;

    }

    unsigned char bits[8];

    unsigned int index, padLen;

    // Save number of bits

    encode(bits, count, 8);

    // Pad out to 56 mod 64.

    index = static_cast<unsigned int>((count[0] >> 3) & 0x3f);

    padLen = (index < 56) ? (56 - index) : (120 - index);

    update(PADDING, padLen);

    // Append length (before padding)

    update(bits, 8);

    // Store state in digest_val

    encode(digest_val, state, 16);

    // Zeroize sensitive information.

    memset(state, 0, sizeof(state));

    memset(count, 0, sizeof(count));

    memset(buffer, 0, sizeof(buffer));

    finalized = true;

}

void

MD5_native::digest(Digest result)

{

    memcpy(result, digest_val, sizeof(digest_val));

}

// MD5 basic transformation. Transforms state based on block.

//

// NB The algorithm intentionally relies on unsigned integer wrap-around

void MD5_native::transform(uint32_t state[4], unsigned char block[64])

#if defined(__clang__)

__attribute__((no_sanitize("unsigned-integer-overflow")))

#endif

{

    uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];

    decode(x, block, 64);

    // Round 1

    FF (a, b, c, d, x[ 0], S11, 0xd76aa478); // 1

    FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); // 2

    FF (c, d, a, b, x[ 2], S13, 0x242070db); // 3

    FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); // 4

    FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); // 5

    FF (d, a, b, c, x[ 5], S12, 0x4787c62a); // 6

    FF (c, d, a, b, x[ 6], S13, 0xa8304613); // 7

    FF (b, c, d, a, x[ 7], S14, 0xfd469501); // 8

    FF (a, b, c, d, x[ 8], S11, 0x698098d8); // 9

    FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); // 10

    FF (c, d, a, b, x[10], S13, 0xffff5bb1); // 11

    FF (b, c, d, a, x[11], S14, 0x895cd7be); // 12

    FF (a, b, c, d, x[12], S11, 0x6b901122); // 13

    FF (d, a, b, c, x[13], S12, 0xfd987193); // 14

    FF (c, d, a, b, x[14], S13, 0xa679438e); // 15

    FF (b, c, d, a, x[15], S14, 0x49b40821); // 16

    // Round 2

    GG (a, b, c, d, x[ 1], S21, 0xf61e2562); // 17

    GG (d, a, b, c, x[ 6], S22, 0xc040b340); // 18

    GG (c, d, a, b, x[11], S23, 0x265e5a51); // 19

    GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); // 20

    GG (a, b, c, d, x[ 5], S21, 0xd62f105d); // 21

    GG (d, a, b, c, x[10], S22,  0x2441453); // 22

    GG (c, d, a, b, x[15], S23, 0xd8a1e681); // 23

    GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); // 24

    GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); // 25

    GG (d, a, b, c, x[14], S22, 0xc33707d6); // 26

    GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); // 27

    GG (b, c, d, a, x[ 8], S24, 0x455a14ed); // 28

    GG (a, b, c, d, x[13], S21, 0xa9e3e905); // 29

    GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); // 30

    GG (c, d, a, b, x[ 7], S23, 0x676f02d9); // 31

    GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); // 32

    // Round 3

    HH (a, b, c, d, x[ 5], S31, 0xfffa3942); // 33

    HH (d, a, b, c, x[ 8], S32, 0x8771f681); // 34

    HH (c, d, a, b, x[11], S33, 0x6d9d6122); // 35

    HH (b, c, d, a, x[14], S34, 0xfde5380c); // 36

    HH (a, b, c, d, x[ 1], S31, 0xa4beea44); // 37

    HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); // 38

    HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); // 39

    HH (b, c, d, a, x[10], S34, 0xbebfbc70); // 40

    HH (a, b, c, d, x[13], S31, 0x289b7ec6); // 41

    HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); // 42

    HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); // 43

    HH (b, c, d, a, x[ 6], S34,  0x4881d05); // 44

    HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); // 45

    HH (d, a, b, c, x[12], S32, 0xe6db99e5); // 46

    HH (c, d, a, b, x[15], S33, 0x1fa27cf8); // 47

    HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); // 48

    // Round 4

    II (a, b, c, d, x[ 0], S41, 0xf4292244); // 49

    II (d, a, b, c, x[ 7], S42, 0x432aff97); // 50

    II (c, d, a, b, x[14], S43, 0xab9423a7); // 51

    II (b, c, d, a, x[ 5], S44, 0xfc93a039); // 52

    II (a, b, c, d, x[12], S41, 0x655b59c3); // 53

    II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); // 54

    II (c, d, a, b, x[10], S43, 0xffeff47d); // 55

    II (b, c, d, a, x[ 1], S44, 0x85845dd1); // 56

    II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); // 57

    II (d, a, b, c, x[15], S42, 0xfe2ce6e0); // 58

    II (c, d, a, b, x[ 6], S43, 0xa3014314); // 59

    II (b, c, d, a, x[13], S44, 0x4e0811a1); // 60

    II (a, b, c, d, x[ 4], S41, 0xf7537e82); // 61

    II (d, a, b, c, x[11], S42, 0xbd3af235); // 62

    II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); // 63

    II (b, c, d, a, x[ 9], S44, 0xeb86d391); // 64

    state[0] += a;

    state[1] += b;

    state[2] += c;

    state[3] += d;

    // Zeroize sensitive information.

    memset (x, 0, sizeof (x));

}

// Encodes input (uint32_t) into output (unsigned char). Assumes len is a

// multiple of 4.

void MD5_native::encode(unsigned char *output, uint32_t *input, size_t len)

{

    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4) {

        output[j] = static_cast<unsigned char>(input[i] & 0xff);

        output[j+1] = static_cast<unsigned char>((input[i] >> 8) & 0xff);

        output[j+2] = static_cast<unsigned char>((input[i] >> 16) & 0xff);

        output[j+3] = static_cast<unsigned char>((input[i] >> 24) & 0xff);

    }

}

// Decodes input (unsigned char) into output (uint32_t). Assumes len is a

// multiple of 4.

void MD5_native::decode(uint32_t *output, unsigned char *input, size_t len)

{

    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4)

        output[i] =

            static_cast<uint32_t>(input[j]) |

            (static_cast<uint32_t>(input[j+1]) << 8) |

            (static_cast<uint32_t>(input[j+2]) << 16) |

            (static_cast<uint32_t>(input[j+3]) << 24);

}