// SPDX-License-Identifier: BSD-3-Clause

/*

 * Copyright (C) 2004 6WIND

 *                          <Vincent.Jardin@6WIND.com>

 * All rights reserved.

 *

 * This MD5 code is Big endian and Little Endian compatible.

 */

/*

 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.

 * All rights reserved.

 */

#include <zebra.h>

#include "md5.h"

#define SHIFT(X, s) (((X) << (s)) | ((X) >> (32 - (s))))

#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)))

#define ROUND1(a, b, c, d, k, s, i)                                            \

  {                                                                      \

    (a) = (a) + F((b), (c), (d)) + X[(k)] + T[(i)];                \

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

    (a) = (b) + (a);                                               \

  }

#define ROUND2(a, b, c, d, k, s, i)                                            \

  {                                                                      \

    (a) = (a) + G((b), (c), (d)) + X[(k)] + T[(i)];                \

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

    (a) = (b) + (a);                                               \

  }

#define ROUND3(a, b, c, d, k, s, i)                                            \

  {                                                                      \

    (a) = (a) + H((b), (c), (d)) + X[(k)] + T[(i)];                \

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

    (a) = (b) + (a);                                               \

  }

#define ROUND4(a, b, c, d, k, s, i)                                            \

  {                                                                      \

    (a) = (a) + I((b), (c), (d)) + X[(k)] + T[(i)];                \

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

    (a) = (b) + (a);                                               \

  }

#define Sa   7

#define Sb  12

#define Sc  17

#define Sd  22

#define Se   5

#define Sf   9

#define Sg  14

#define Sh  20

#define Si   4

#define Sj  11

#define Sk  16

#define Sl  23

#define Sm   6

#define Sn  10

#define So  15

#define Sp  21

#define MD5_A0  0x67452301

#define MD5_B0  0xefcdab89

#define MD5_C0  0x98badcfe

#define MD5_D0  0x10325476

/* Integer part of 4294967296 times abs(sin(i)), where i is in radians. */

static const uint32_t T[65] = {

  0,    0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf,

  0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1,

  0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,

  0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x2441453,

  0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,

  0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,

  0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9,

  0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05,

  0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,

  0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92,

  0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,

  0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391,

};

static const uint8_t md5_paddat[MD5_BUFLEN] = {

  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,

};

static void md5_calc(const uint8_t *, md5_ctxt *);

void md5_init(md5_ctxt *ctxt)

{

  ctxt->md5_n = 0;

  ctxt->md5_i = 0;

  ctxt->md5_sta = MD5_A0;

  ctxt->md5_stb = MD5_B0;

  ctxt->md5_stc = MD5_C0;

  ctxt->md5_std = MD5_D0;

  memset(ctxt->md5_buf, 0, sizeof(ctxt->md5_buf));

}

void md5_loop(md5_ctxt *ctxt, const void *vinput, uint len)

{

  uint gap, i;

  const uint8_t *input = vinput;

  ctxt->md5_n += len * 8; /* byte to bit */

  gap = MD5_BUFLEN - ctxt->md5_i;

  if (len >= gap) {

    memcpy(ctxt->md5_buf + ctxt->md5_i, input, gap);

    md5_calc(ctxt->md5_buf, ctxt);

    for (i = gap; i + MD5_BUFLEN <= len; i += MD5_BUFLEN) {

      md5_calc((input + i), ctxt);

    }

    ctxt->md5_i = len - i;

    memcpy(ctxt->md5_buf, (input + i), ctxt->md5_i);

  } else {

    memcpy(ctxt->md5_buf + ctxt->md5_i, input, len);

    ctxt->md5_i += len;

  }

}

void md5_pad(md5_ctxt *ctxt)

{

  uint gap;

  /* Don't count up padding. Keep md5_n. */

  gap = MD5_BUFLEN - ctxt->md5_i;

  if (gap > 8) {

    memcpy(ctxt->md5_buf + ctxt->md5_i, md5_paddat,

           gap - sizeof(ctxt->md5_n));

  } else {

    /* including gap == 8 */

    memcpy(ctxt->md5_buf + ctxt->md5_i, md5_paddat, gap);

    md5_calc(ctxt->md5_buf, ctxt);

    memcpy(ctxt->md5_buf, md5_paddat + gap,

           MD5_BUFLEN - sizeof(ctxt->md5_n));

  }

  /* 8 byte word */

  if (BYTE_ORDER == LITTLE_ENDIAN)

    memcpy(&ctxt->md5_buf[56], &ctxt->md5_n8[0], 8);

  else {

    ctxt->md5_buf[56] = ctxt->md5_n8[7];

    ctxt->md5_buf[57] = ctxt->md5_n8[6];

    ctxt->md5_buf[58] = ctxt->md5_n8[5];

    ctxt->md5_buf[59] = ctxt->md5_n8[4];

    ctxt->md5_buf[60] = ctxt->md5_n8[3];

    ctxt->md5_buf[61] = ctxt->md5_n8[2];

    ctxt->md5_buf[62] = ctxt->md5_n8[1];

    ctxt->md5_buf[63] = ctxt->md5_n8[0];

  }

  md5_calc(ctxt->md5_buf, ctxt);

}

void md5_result(uint8_t *digest, md5_ctxt *ctxt)

{

  /* 4 byte words */

  if (BYTE_ORDER == LITTLE_ENDIAN)

    memcpy(digest, &ctxt->md5_st8[0], 16);

  else if (BYTE_ORDER == BIG_ENDIAN) {

    digest[0] = ctxt->md5_st8[3];

    digest[1] = ctxt->md5_st8[2];

    digest[2] = ctxt->md5_st8[1];

    digest[3] = ctxt->md5_st8[0];

    digest[4] = ctxt->md5_st8[7];

    digest[5] = ctxt->md5_st8[6];

    digest[6] = ctxt->md5_st8[5];

    digest[7] = ctxt->md5_st8[4];

    digest[8] = ctxt->md5_st8[11];

    digest[9] = ctxt->md5_st8[10];

    digest[10] = ctxt->md5_st8[9];

    digest[11] = ctxt->md5_st8[8];

    digest[12] = ctxt->md5_st8[15];

    digest[13] = ctxt->md5_st8[14];

    digest[14] = ctxt->md5_st8[13];

    digest[15] = ctxt->md5_st8[12];

  }

}

static void md5_calc(const uint8_t *b64, md5_ctxt *ctxt)

{

  uint32_t A = ctxt->md5_sta;

  uint32_t B = ctxt->md5_stb;

  uint32_t C = ctxt->md5_stc;

  uint32_t D = ctxt->md5_std;

#if (BYTE_ORDER == LITTLE_ENDIAN)

  const uint32_t *X = (const uint32_t *)b64;

#elif (BYTE_ORDER == BIG_ENDIAN)

  uint32_t X[16];

  if (BYTE_ORDER == BIG_ENDIAN) {

    /* 4 byte words */

    /* what a brute force but fast! */

    uint8_t *y = (uint8_t *)X;

    y[0] = b64[3];

    y[1] = b64[2];

    y[2] = b64[1];

    y[3] = b64[0];

    y[4] = b64[7];

    y[5] = b64[6];

    y[6] = b64[5];

    y[7] = b64[4];

    y[8] = b64[11];

    y[9] = b64[10];

    y[10] = b64[9];

    y[11] = b64[8];

    y[12] = b64[15];

    y[13] = b64[14];

    y[14] = b64[13];

    y[15] = b64[12];

    y[16] = b64[19];

    y[17] = b64[18];

    y[18] = b64[17];

    y[19] = b64[16];

    y[20] = b64[23];

    y[21] = b64[22];

    y[22] = b64[21];

    y[23] = b64[20];

    y[24] = b64[27];

    y[25] = b64[26];

    y[26] = b64[25];

    y[27] = b64[24];

    y[28] = b64[31];

    y[29] = b64[30];

    y[30] = b64[29];

    y[31] = b64[28];

    y[32] = b64[35];

    y[33] = b64[34];

    y[34] = b64[33];

    y[35] = b64[32];

    y[36] = b64[39];

    y[37] = b64[38];

    y[38] = b64[37];

    y[39] = b64[36];

    y[40] = b64[43];

    y[41] = b64[42];

    y[42] = b64[41];

    y[43] = b64[40];

    y[44] = b64[47];

    y[45] = b64[46];

    y[46] = b64[45];

    y[47] = b64[44];

    y[48] = b64[51];

    y[49] = b64[50];

    y[50] = b64[49];

    y[51] = b64[48];

    y[52] = b64[55];

    y[53] = b64[54];

    y[54] = b64[53];

    y[55] = b64[52];

    y[56] = b64[59];

    y[57] = b64[58];

    y[58] = b64[57];

    y[59] = b64[56];

    y[60] = b64[63];

    y[61] = b64[62];

    y[62] = b64[61];

    y[63] = b64[60];

  }

#endif

  ROUND1(A, B, C, D, 0, Sa, 1);

  ROUND1(D, A, B, C, 1, Sb, 2);

  ROUND1(C, D, A, B, 2, Sc, 3);

  ROUND1(B, C, D, A, 3, Sd, 4);

  ROUND1(A, B, C, D, 4, Sa, 5);

  ROUND1(D, A, B, C, 5, Sb, 6);

  ROUND1(C, D, A, B, 6, Sc, 7);

  ROUND1(B, C, D, A, 7, Sd, 8);

  ROUND1(A, B, C, D, 8, Sa, 9);

  ROUND1(D, A, B, C, 9, Sb, 10);

  ROUND1(C, D, A, B, 10, Sc, 11);

  ROUND1(B, C, D, A, 11, Sd, 12);

  ROUND1(A, B, C, D, 12, Sa, 13);

  ROUND1(D, A, B, C, 13, Sb, 14);

  ROUND1(C, D, A, B, 14, Sc, 15);

  ROUND1(B, C, D, A, 15, Sd, 16);

  ROUND2(A, B, C, D, 1, Se, 17);

  ROUND2(D, A, B, C, 6, Sf, 18);

  ROUND2(C, D, A, B, 11, Sg, 19);

  ROUND2(B, C, D, A, 0, Sh, 20);

  ROUND2(A, B, C, D, 5, Se, 21);

  ROUND2(D, A, B, C, 10, Sf, 22);

  ROUND2(C, D, A, B, 15, Sg, 23);

  ROUND2(B, C, D, A, 4, Sh, 24);

  ROUND2(A, B, C, D, 9, Se, 25);

  ROUND2(D, A, B, C, 14, Sf, 26);

  ROUND2(C, D, A, B, 3, Sg, 27);

  ROUND2(B, C, D, A, 8, Sh, 28);

  ROUND2(A, B, C, D, 13, Se, 29);

  ROUND2(D, A, B, C, 2, Sf, 30);

  ROUND2(C, D, A, B, 7, Sg, 31);

  ROUND2(B, C, D, A, 12, Sh, 32);

  ROUND3(A, B, C, D, 5, Si, 33);

  ROUND3(D, A, B, C, 8, Sj, 34);

  ROUND3(C, D, A, B, 11, Sk, 35);

  ROUND3(B, C, D, A, 14, Sl, 36);

  ROUND3(A, B, C, D, 1, Si, 37);

  ROUND3(D, A, B, C, 4, Sj, 38);

  ROUND3(C, D, A, B, 7, Sk, 39);

  ROUND3(B, C, D, A, 10, Sl, 40);

  ROUND3(A, B, C, D, 13, Si, 41);

  ROUND3(D, A, B, C, 0, Sj, 42);

  ROUND3(C, D, A, B, 3, Sk, 43);

  ROUND3(B, C, D, A, 6, Sl, 44);

  ROUND3(A, B, C, D, 9, Si, 45);

  ROUND3(D, A, B, C, 12, Sj, 46);

  ROUND3(C, D, A, B, 15, Sk, 47);

  ROUND3(B, C, D, A, 2, Sl, 48);

  ROUND4(A, B, C, D, 0, Sm, 49);

  ROUND4(D, A, B, C, 7, Sn, 50);

  ROUND4(C, D, A, B, 14, So, 51);

  ROUND4(B, C, D, A, 5, Sp, 52);

  ROUND4(A, B, C, D, 12, Sm, 53);

  ROUND4(D, A, B, C, 3, Sn, 54);

  ROUND4(C, D, A, B, 10, So, 55);

  ROUND4(B, C, D, A, 1, Sp, 56);

  ROUND4(A, B, C, D, 8, Sm, 57);

  ROUND4(D, A, B, C, 15, Sn, 58);

  ROUND4(C, D, A, B, 6, So, 59);

  ROUND4(B, C, D, A, 13, Sp, 60);

  ROUND4(A, B, C, D, 4, Sm, 61);

  ROUND4(D, A, B, C, 11, Sn, 62);

  ROUND4(C, D, A, B, 2, So, 63);

  ROUND4(B, C, D, A, 9, Sp, 64);

  ctxt->md5_sta += A;

  ctxt->md5_stb += B;

  ctxt->md5_stc += C;

  ctxt->md5_std += D;

}

/* From RFC 2104 */

void hmac_md5(unsigned char *text, int text_len, unsigned char *key,

        int key_len, uint8_t *digest)

{

  MD5_CTX context;

  unsigned char k_ipad[65]; /* inner padding -

          * key XORd with ipad

          */

  unsigned char k_opad[65]; /* outer padding -

          * key XORd with opad

          */

  unsigned char tk[16];

  int i;

  /* if key is longer than 64 bytes reset it to key=MD5(key) */

  if (key_len > 64) {

    MD5_CTX tctx;

    MD5Init(&tctx);

    MD5Update(&tctx, key, key_len);

    MD5Final(tk, &tctx);

    key = tk;

    key_len = 16;

  }

  /*

   * the HMAC_MD5 transform looks like:

   *

   * MD5(K XOR opad, MD5(K XOR ipad, text))

   *

   * where K is an n byte key

   * ipad is the byte 0x36 repeated 64 times

   * opad is the byte 0x5c repeated 64 times

   * and text is the data being protected

   */

  /* start out by storing key in pads */

  bzero(k_ipad, sizeof(k_ipad));

  bzero(k_opad, sizeof(k_opad));

  bcopy(key, k_ipad, key_len);

  bcopy(key, k_opad, key_len);

  /* XOR key with ipad and opad values */

  for (i = 0; i < 64; i++) {

    k_ipad[i] ^= 0x36;

    k_opad[i] ^= 0x5c;

  }

  /*

   * perform inner MD5

   */

  MD5Init(&context);          /* init context for 1st

            * pass */

  MD5Update(&context, k_ipad, 64);       /* start with inner pad */

  MD5Update(&context, text, text_len);   /* then text of datagram */

  MD5Final(digest, &context); /* finish up 1st pass */

  /*

   * perform outer MD5

   */

  MD5Init(&context);          /* init context for 2nd

            * pass */

  MD5Update(&context, k_opad, 64);       /* start with outer pad */

  MD5Update(&context, digest, 16);       /* then results of 1st

            * hash */

  MD5Final(digest, &context); /* finish up 2nd pass */

  explicit_bzero(&context, sizeof(context));

}