/** A local MD5 implementation

 *

 * @note license is LGPL, but largely derived from a public domain source.

 *

 * @file src/lib/util/md5.c

 */

RCSID("$Id: b236a4acb6bb1283a1c656c7a3dba5693d379fb3 $")

#include <freeradius-devel/util/debug.h>

#include <freeradius-devel/util/strerror.h>

#include <freeradius-devel/util/atexit.h>

/*

 *  FORCE MD5 TO USE OUR MD5 HEADER FILE!

 *  If we don't do this, it might pick up the systems broken MD5.

 */

#include <freeradius-devel/util/md5.h>

/** The thread local free list

 *

 * Any entries remaining in the list will be freed when the thread is joined

 */

#define ARRAY_SIZE (8)

typedef struct {

  bool    used;

  fr_md5_ctx_t  *md_ctx;

} fr_md5_free_list_t;

static _Thread_local fr_md5_free_list_t *md5_array;

static void fr_md5_local_ctx_reset(fr_md5_ctx_t *ctx);

static void fr_md5_local_ctx_copy(fr_md5_ctx_t *dst, fr_md5_ctx_t const *src);

static fr_md5_ctx_t *fr_md5_local_ctx_alloc(void);

static void fr_md5_local_ctx_free(fr_md5_ctx_t **ctx);

static void fr_md5_local_update(fr_md5_ctx_t *ctx, uint8_t const *in, size_t inlen);

static void fr_md5_local_final(uint8_t out[static MD5_DIGEST_LENGTH], fr_md5_ctx_t *ctx);

static fr_md5_funcs_t md5_local_funcs = {

  .reset = fr_md5_local_ctx_reset,

  .copy = fr_md5_local_ctx_copy,

  .alloc = fr_md5_local_ctx_alloc,

  .free = fr_md5_local_ctx_free,

  .update = fr_md5_local_update,

  .final = fr_md5_local_final

};

fr_md5_funcs_t const *fr_md5_funcs = &md5_local_funcs;

/*

 *  If we have OpenSSL's EVP API available, then build wrapper functions.

 *

 *  We always need to build the local MD5 functions as OpenSSL could

 *  be operating in FIPS mode where MD5 digest functions are unavailable.

 */

#ifdef HAVE_OPENSSL_EVP_H

#  include <freeradius-devel/tls/openssl_user_macros.h>

#  include <openssl/evp.h>

#  include <openssl/crypto.h>

#  include <openssl/err.h>

#  include <openssl/provider.h>

/** @copydoc fr_md5_ctx_reset

 *

 */

static void fr_md5_openssl_ctx_reset(fr_md5_ctx_t *ctx)

{

  EVP_MD_CTX *md_ctx = ctx;

  EVP_MD_CTX_reset(md_ctx);

  (void)EVP_DigestInit_ex(md_ctx, EVP_md5(), NULL);

}

/** @copydoc fr_md5_ctx_copy

 *

 */

static void fr_md5_openssl_ctx_copy(fr_md5_ctx_t *dst, fr_md5_ctx_t const *src)

{

  EVP_MD_CTX_copy_ex(dst, src);

}

/** @copydoc fr_md5_ctx_alloc

 *

 */

static fr_md5_ctx_t *fr_md5_openssl_ctx_alloc(void)

{

  EVP_MD_CTX *md_ctx;

  md_ctx = EVP_MD_CTX_new();

  if (unlikely(!md_ctx)) return NULL;

  if (EVP_DigestInit_ex(md_ctx, EVP_md5(), NULL) != 1) {

    char buffer[256];

    ERR_error_string_n(ERR_get_error(), buffer, sizeof(buffer));

    fr_strerror_printf("Failed initialising MD5 ctx: %s", buffer);

    EVP_MD_CTX_free(md_ctx);

    return NULL;

  }

  return md_ctx;

}

/** @copydoc fr_md5_ctx_free

 *

 */

static void fr_md5_openssl_ctx_free(fr_md5_ctx_t **ctx)

{

  if (!*ctx) return;

  EVP_MD_CTX_free(*ctx);

  *ctx = NULL;

}

/** @copydoc fr_md5_update

 *

 */

static void fr_md5_openssl_update(fr_md5_ctx_t *ctx, uint8_t const *in, size_t inlen)

{

  EVP_DigestUpdate(ctx, in, inlen);

}

/** @copydoc fr_md5_final

 *

 */

static void fr_md5_openssl_final(uint8_t out[static MD5_DIGEST_LENGTH], fr_md5_ctx_t *ctx)

{

  unsigned int len;

  EVP_DigestFinal(ctx, out, &len);

  if (!fr_cond_assert(len == MD5_DIGEST_LENGTH)) return;

}

static fr_md5_funcs_t md5_openssl_funcs = {

  .reset = fr_md5_openssl_ctx_reset,

  .copy = fr_md5_openssl_ctx_copy,

  .alloc = fr_md5_openssl_ctx_alloc,

  .free = fr_md5_openssl_ctx_free,

  .update = fr_md5_openssl_update,

  .final = fr_md5_openssl_final

};

#endif

#  define MD5_BLOCK_LENGTH 64

typedef struct {

  uint32_t state[4];      //!< State.

  uint32_t count[2];      //!< Number of bits, mod 2^64.

  uint8_t buffer[MD5_BLOCK_LENGTH]; //!< Input buffer.

} fr_md5_ctx_local_t;

/*

 * This code implements the MD5 message-digest algorithm.

 * The algorithm is due to Ron Rivest.  This code was

 * written by Colin Plumb in 1993, no copyright is claimed.

 * This code is in the public domain; do with it what you wish.

 *

 * Equivalent code is available from RSA Data Security, Inc.

 * This code has been tested against that, and is equivalent,

 * except that you don't need to include two pages of legalese

 * with every copy.

 *

 * To compute the message digest of a chunk of bytes, declare an

 * MD5Context structure, pass it to fr_md5_init, call fr_md5_update as

 * needed on buffers full of bytes, and then call fr_md5_final, which

 * will fill a supplied 16-byte array with the digest.

 */

#define PUT_64BIT_LE(cp, value) do {\

  (cp)[7] = (value)[1] >> 24;\

  (cp)[6] = (value)[1] >> 16;\

  (cp)[5] = (value)[1] >> 8;\

  (cp)[4] = (value)[1];\

  (cp)[3] = (value)[0] >> 24;\

  (cp)[2] = (value)[0] >> 16;\

  (cp)[1] = (value)[0] >> 8;\

  (cp)[0] = (value)[0];\

} while (0)

#define PUT_32BIT_LE(cp, value) do {\

  (cp)[3] = (value) >> 24;\

  (cp)[2] = (value) >> 16;\

  (cp)[1] = (value) >> 8;\

  (cp)[0] = (value);\

} while (0)

static const uint8_t PADDING[MD5_BLOCK_LENGTH] = {

  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

};

/* The four core functions - MD5_F1 is optimized somewhat */

#define MD5_F1(x, y, z) (z ^ (x & (y ^ z)))

#define MD5_F2(x, y, z) MD5_F1(z, x, y)

#define MD5_F3(x, y, z) (x ^ y ^ z)

#define MD5_F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */

#define MD5STEP(f, w, x, y, z, data, s) (w += f(x, y, z) + data, w = w << s | w >> (32 - s),  w += x)

/** The core of the MD5 algorithm

 *

 * This alters an existing MD5 hash to reflect the addition of 16

 * longwords of new data.  fr_md5_update blocks the data and converts bytes

 * into longwords for this routine.

 *

 * @param[in] state 16 bytes of data to feed into the hashing function.

 * @param[in,out] block MD5 digest block to update.

 */

static void fr_md5_local_transform(uint32_t state[static 4], uint8_t const block[static MD5_BLOCK_LENGTH])

{

  uint32_t a, b, c, d, in[MD5_BLOCK_LENGTH / 4];

  for (a = 0; a < (MD5_BLOCK_LENGTH / 4); a++) {

    size_t idx = a * 4;

    in[a] = (uint32_t)(

        (uint32_t)(block[idx + 0]) |

        (uint32_t)(block[idx + 1]) <<  8 |

        (uint32_t)(block[idx + 2]) << 16 |

        (uint32_t)(block[idx + 3]) << 24);

  }

  a = state[0];

  b = state[1];

  c = state[2];

  d = state[3];

  MD5STEP(MD5_F1, a, b, c, d, in[ 0] + 0xd76aa478,  7);

  MD5STEP(MD5_F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12);

  MD5STEP(MD5_F1, c, d, a, b, in[ 2] + 0x242070db, 17);

  MD5STEP(MD5_F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22);

  MD5STEP(MD5_F1, a, b, c, d, in[ 4] + 0xf57c0faf,  7);

  MD5STEP(MD5_F1, d, a, b, c, in[ 5] + 0x4787c62a, 12);

  MD5STEP(MD5_F1, c, d, a, b, in[ 6] + 0xa8304613, 17);

  MD5STEP(MD5_F1, b, c, d, a, in[ 7] + 0xfd469501, 22);

  MD5STEP(MD5_F1, a, b, c, d, in[ 8] + 0x698098d8,  7);

  MD5STEP(MD5_F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12);

  MD5STEP(MD5_F1, c, d, a, b, in[10] + 0xffff5bb1, 17);

  MD5STEP(MD5_F1, b, c, d, a, in[11] + 0x895cd7be, 22);

  MD5STEP(MD5_F1, a, b, c, d, in[12] + 0x6b901122,  7);

  MD5STEP(MD5_F1, d, a, b, c, in[13] + 0xfd987193, 12);

  MD5STEP(MD5_F1, c, d, a, b, in[14] + 0xa679438e, 17);

  MD5STEP(MD5_F1, b, c, d, a, in[15] + 0x49b40821, 22);

  MD5STEP(MD5_F2, a, b, c, d, in[ 1] + 0xf61e2562,  5);

  MD5STEP(MD5_F2, d, a, b, c, in[ 6] + 0xc040b340,  9);

  MD5STEP(MD5_F2, c, d, a, b, in[11] + 0x265e5a51, 14);

  MD5STEP(MD5_F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20);

  MD5STEP(MD5_F2, a, b, c, d, in[ 5] + 0xd62f105d,  5);

  MD5STEP(MD5_F2, d, a, b, c, in[10] + 0x02441453,  9);

  MD5STEP(MD5_F2, c, d, a, b, in[15] + 0xd8a1e681, 14);

  MD5STEP(MD5_F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20);

  MD5STEP(MD5_F2, a, b, c, d, in[ 9] + 0x21e1cde6,  5);

  MD5STEP(MD5_F2, d, a, b, c, in[14] + 0xc33707d6,  9);

  MD5STEP(MD5_F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14);

  MD5STEP(MD5_F2, b, c, d, a, in[ 8] + 0x455a14ed, 20);

  MD5STEP(MD5_F2, a, b, c, d, in[13] + 0xa9e3e905,  5);

  MD5STEP(MD5_F2, d, a, b, c, in[ 2] + 0xfcefa3f8,  9);

  MD5STEP(MD5_F2, c, d, a, b, in[ 7] + 0x676f02d9, 14);

  MD5STEP(MD5_F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

  MD5STEP(MD5_F3, a, b, c, d, in[ 5] + 0xfffa3942,  4);

  MD5STEP(MD5_F3, d, a, b, c, in[ 8] + 0x8771f681, 11);

  MD5STEP(MD5_F3, c, d, a, b, in[11] + 0x6d9d6122, 16);

  MD5STEP(MD5_F3, b, c, d, a, in[14] + 0xfde5380c, 23);

  MD5STEP(MD5_F3, a, b, c, d, in[ 1] + 0xa4beea44,  4);

  MD5STEP(MD5_F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11);

  MD5STEP(MD5_F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16);

  MD5STEP(MD5_F3, b, c, d, a, in[10] + 0xbebfbc70, 23);

  MD5STEP(MD5_F3, a, b, c, d, in[13] + 0x289b7ec6,  4);

  MD5STEP(MD5_F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11);

  MD5STEP(MD5_F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16);

  MD5STEP(MD5_F3, b, c, d, a, in[ 6] + 0x04881d05, 23);

  MD5STEP(MD5_F3, a, b, c, d, in[ 9] + 0xd9d4d039,  4);

  MD5STEP(MD5_F3, d, a, b, c, in[12] + 0xe6db99e5, 11);

  MD5STEP(MD5_F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);

  MD5STEP(MD5_F3, b, c, d, a, in[2 ] + 0xc4ac5665, 23);

  MD5STEP(MD5_F4, a, b, c, d, in[ 0] + 0xf4292244,  6);

  MD5STEP(MD5_F4, d, a, b, c, in[7 ] + 0x432aff97, 10);

  MD5STEP(MD5_F4, c, d, a, b, in[14] + 0xab9423a7, 15);

  MD5STEP(MD5_F4, b, c, d, a, in[5 ] + 0xfc93a039, 21);

  MD5STEP(MD5_F4, a, b, c, d, in[12] + 0x655b59c3,  6);

  MD5STEP(MD5_F4, d, a, b, c, in[3 ] + 0x8f0ccc92, 10);

  MD5STEP(MD5_F4, c, d, a, b, in[10] + 0xffeff47d, 15);

  MD5STEP(MD5_F4, b, c, d, a, in[1 ] + 0x85845dd1, 21);

  MD5STEP(MD5_F4, a, b, c, d, in[8 ] + 0x6fa87e4f,  6);

  MD5STEP(MD5_F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);

  MD5STEP(MD5_F4, c, d, a, b, in[6 ] + 0xa3014314, 15);

  MD5STEP(MD5_F4, b, c, d, a, in[13] + 0x4e0811a1, 21);

  MD5STEP(MD5_F4, a, b, c, d, in[4 ] + 0xf7537e82,  6);

  MD5STEP(MD5_F4, d, a, b, c, in[11] + 0xbd3af235, 10);

  MD5STEP(MD5_F4, c, d, a, b, in[2 ] + 0x2ad7d2bb, 15);

  MD5STEP(MD5_F4, b, c, d, a, in[9 ] + 0xeb86d391, 21);

  state[0] += a;

  state[1] += b;

  state[2] += c;

  state[3] += d;

}

/** @copydoc fr_md5_ctx_reset

 *

 */

static void fr_md5_local_ctx_reset(fr_md5_ctx_t *ctx)

{

  fr_md5_ctx_local_t  *ctx_local = talloc_get_type_abort(ctx, fr_md5_ctx_local_t);

  ctx_local->count[0] = 0;

  ctx_local->count[1] = 0;

  ctx_local->state[0] = 0x67452301;

  ctx_local->state[1] = 0xefcdab89;

  ctx_local->state[2] = 0x98badcfe;

  ctx_local->state[3] = 0x10325476;

  memset(ctx_local->buffer, 0, sizeof(ctx_local->buffer));

}

/** @copydoc fr_md5_ctx_copy

 *

 */

static void fr_md5_local_ctx_copy(fr_md5_ctx_t *dst, fr_md5_ctx_t const *src)

{

  fr_md5_ctx_local_t const *ctx_local_src = talloc_get_type_abort_const(src, fr_md5_ctx_local_t);

  fr_md5_ctx_local_t *ctx_local_dst = talloc_get_type_abort(dst, fr_md5_ctx_local_t);

  memcpy(ctx_local_dst, ctx_local_src, sizeof(*ctx_local_dst));

}

/** @copydoc fr_md5_ctx_alloc

 *

 */

static fr_md5_ctx_t *fr_md5_local_ctx_alloc(void)

{

  fr_md5_ctx_local_t *ctx_local;

  ctx_local = talloc(NULL, fr_md5_ctx_local_t);

  if (unlikely(!ctx_local)) return NULL;

  fr_md5_local_ctx_reset(ctx_local);

  return ctx_local;

}

/** @copydoc fr_md5_ctx_free

 *

 */

static void fr_md5_local_ctx_free(fr_md5_ctx_t **ctx)

{

  talloc_free(*ctx);

  *ctx = NULL;

}

static const uint8_t *zero = (uint8_t[]){ 0x00 };

/** @copydoc fr_md5_update

 *

 */

static void fr_md5_local_update(fr_md5_ctx_t *ctx, uint8_t const *in, size_t inlen)

{

  fr_md5_ctx_local_t  *ctx_local = talloc_get_type_abort(ctx, fr_md5_ctx_local_t);

  size_t have, need;

  /*

   *  Needed so we can calculate the zero

   *  length md5 hash correctly.

   *  ubsan doesn't like arithmetic on

   *  NULL pointers.

   */

  if (!in) {

    in = zero;

    inlen = 0;

  }

  /* Check how many bytes we already have and how many more we need. */

  have = (size_t)((ctx_local->count[0] >> 3) & (MD5_BLOCK_LENGTH - 1));

  need = MD5_BLOCK_LENGTH - have;

  /* Update bitcount */

/*  ctx_local->count += (uint64_t)inlen << 3;*/

  if ((ctx_local->count[0] += ((uint32_t)inlen << 3)) < (uint32_t)inlen) {

  /* Overflowed ctx_local->count[0] */

    ctx_local->count[1]++;

  }

  ctx_local->count[1] += ((uint32_t)inlen >> 29);

  if (inlen >= need) {

    if (have != 0) {

      memcpy(ctx_local->buffer + have, in, need);

      fr_md5_local_transform(ctx_local->state, ctx_local->buffer);

      in += need;

      inlen -= need;

      have = 0;

    }

    /* Process data in MD5_BLOCK_LENGTH-byte chunks. */

    while (inlen >= MD5_BLOCK_LENGTH) {

      fr_md5_local_transform(ctx_local->state, in);

      in += MD5_BLOCK_LENGTH;

      inlen -= MD5_BLOCK_LENGTH;

    }

  }

  /* Handle any remaining bytes of data. */

  memcpy(ctx_local->buffer + have, in, inlen);

}

/** @copydoc fr_md5_final

 *

 */

static void fr_md5_local_final(uint8_t out[static MD5_DIGEST_LENGTH], fr_md5_ctx_t *ctx)

{

  fr_md5_ctx_local_t  *ctx_local = talloc_get_type_abort(ctx, fr_md5_ctx_local_t);

  uint8_t     count[8];

  size_t      padlen;

  int     i;

  /* Convert count to 8 bytes in little endian order. */

  PUT_64BIT_LE(count, ctx_local->count);

  /* Pad out to 56 mod 64. */

  padlen = MD5_BLOCK_LENGTH -

      ((ctx_local->count[0] >> 3) & (MD5_BLOCK_LENGTH - 1));

  if (padlen < 1 + 8)

    padlen += MD5_BLOCK_LENGTH;

  fr_md5_update(ctx_local, PADDING, padlen - 8); /* padlen - 8 <= 64 */

  fr_md5_update(ctx_local, count, 8);

  for (i = 0; i < 4; i++)

    PUT_32BIT_LE(out + i * 4, ctx_local->state[i]);

  memset(ctx_local, 0, sizeof(*ctx_local)); /* in case it's sensitive */

}

/** Calculate the MD5 hash of the contents of a buffer

 *

 * @param[out] out Where to write the MD5 digest. Must be a minimum of MD5_DIGEST_LENGTH.

 * @param[in] in Data to hash.

 * @param[in] inlen Length of the data.

 */

void fr_md5_calc(uint8_t out[static MD5_DIGEST_LENGTH], uint8_t const *in, size_t inlen)

{

  fr_md5_ctx_t *ctx;

  ctx = fr_md5_ctx_alloc_from_list();

  fr_md5_update(ctx, in, inlen);

  fr_md5_final(out, ctx);

  fr_md5_ctx_free_from_list(&ctx);

}

static int _md5_ctx_free_on_exit(void *arg)

{

  int i;

  fr_md5_free_list_t *free_list = arg;

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

    if (free_list[i].used) continue;

    fr_md5_ctx_free(&free_list[i].md_ctx);

  }

  if (talloc_free(free_list) < 0) return -1;

  md5_array = NULL;

  return 0;

}

/** @copydoc fr_md5_ctx_alloc

 *

 */

fr_md5_ctx_t *fr_md5_ctx_alloc_from_list(void)

{

  int     i;

  fr_md5_ctx_t    *md_ctx;

  fr_md5_free_list_t  *free_list;

  if (unlikely(!md5_array)) {

    free_list = talloc_zero_array(NULL, fr_md5_free_list_t, ARRAY_SIZE);

    if (unlikely(!free_list)) {

    oom:

      fr_strerror_const("Out of Memory");

      return NULL;

    }

    fr_atexit_thread_local(md5_array, _md5_ctx_free_on_exit, free_list);

    /*

     *  Initialize all MD5 contexts

     */

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

      md_ctx = fr_md5_ctx_alloc();

      if (unlikely(md_ctx == NULL)) goto oom;

      free_list[i].md_ctx = md_ctx;

    }

  } else {

    free_list = md5_array;

  }

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

    if (free_list[i].used) continue;

    free_list[i].used = true;

    return free_list[i].md_ctx;

  }

  /*

   *  No more free contexts, just allocate a new one.

   */

  return fr_md5_ctx_alloc();

}

/** @copydoc fr_md5_ctx_free

 *

 */

void fr_md5_ctx_free_from_list(fr_md5_ctx_t **ctx)

{

  int i;

  fr_md5_free_list_t *free_list = md5_array;

  if (free_list) {

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

      if (free_list[i].md_ctx == *ctx) {

        free_list[i].used = false;

        fr_md5_ctx_reset(*ctx);

        *ctx = NULL;

        return;

      }

    }

  }

  fr_md5_ctx_free(*ctx);

  *ctx = NULL;

}

#ifdef HAVE_OPENSSL_EVP_H

static void md5_free_list_reinit(fr_md5_funcs_t *funcs)

{

  int i;

  fr_md5_ctx_t     *md_ctx;

  fr_md5_free_list_t *free_list = md5_array;

  if (!free_list) {

    fr_md5_funcs = funcs;

    return;

  }

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

    fr_assert(!free_list[i].used);

    fr_md5_ctx_free(&free_list[i].md_ctx);

  }

  fr_md5_funcs = funcs;

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

    md_ctx = fr_md5_ctx_alloc();

    fr_assert(md_ctx != NULL);

    free_list[i].md_ctx = md_ctx;

  }

}

void fr_md5_openssl_init(void)

{

  fr_assert(fr_md5_funcs == &md5_local_funcs);

  /*

   *  If we are in FIPS mode, then we still use the local

   *  allocator.

   */

  if (EVP_default_properties_is_fips_enabled(NULL)) return;

  /*

   *  OpenSSL isn't in FIPS mode.  Swap out the functions

   *  pointers for the OpenSSL versions.

   *

   *  We do this by swapping out a pointer to a structure

   *  containing the functions, as this prevents possible

   *  skew where some threads see a mixture of functions.

   */

  md5_free_list_reinit(&md5_openssl_funcs);

}

void fr_md5_openssl_free(void)

{

  if (fr_md5_funcs == &md5_local_funcs) return; /* not initialized, or FIPS. */

  md5_free_list_reinit(&md5_local_funcs);

}

#endif