/*

 * SPDX-License-Identifier: ISC

 *

 * Copyright (c) 2020 Todd C. Miller <Todd.Miller@sudo.ws>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include <config.h>

#include <stdlib.h>

#if defined(HAVE_STDINT_H)

# include <stdint.h>

#elif defined(HAVE_INTTYPES_H)

# include <inttypes.h>

#endif

#include <string.h>

#include <arpa/inet.h>

#include <sudo_compat.h>

#include <sudo_util.h>

#include <sudo_rand.h>

struct uuid {

    uint32_t time_low;

    uint16_t time_mid;

    uint16_t time_hi_and_version;

    uint8_t clock_seq_hi_and_reserved;

    uint8_t clock_seq_low;

    uint8_t node[6];

};

/*

 * Create a type 4 (random), variant 1 universally unique identifier (UUID).

 * As per RFC 4122 section 4.4.

 */

void

sudo_uuid_create_v1(unsigned char uuid_out[restrict static 16])

{

    struct uuid uuid;

    arc4random_buf(&uuid, sizeof(uuid));

    /* Set version to 4 (random), 4 most significant bits (12-15) are 0010. */

    uuid.time_hi_and_version &= 0x0fff;

    uuid.time_hi_and_version |= 0x4000;

    /* Set variant to 1: two most significant bits (6 and 7) are 01. */

    uuid.clock_seq_hi_and_reserved &= 0x3f;

    uuid.clock_seq_hi_and_reserved |= 0x80;

    memcpy(uuid_out, &uuid, 16);

}

/*

 * Format a uuid as a 36-byte string (plus one for the NUL).

 */

char *

sudo_uuid_to_string_v1(const unsigned char uuid[restrict static 16], char * restrict dst, size_t dstsiz)

{

    const char hex[] = "0123456789abcdef";

    char *cp = dst;

    unsigned int i;

    if (dstsiz < sizeof("123e4567-e89b-12d3-a456-426655440000"))

  return NULL;

    for (i = 0; i < 16; i++) {

  *cp++ = hex[uuid[i] >> 4];

  *cp++ = hex[uuid[i] & 0x0f];

  switch (i) {

  case 4:

  case 6:

  case 8:

  case 10:

      *cp++ = '-';

      break;

  }

    }

    *cp = '\0';

    return dst;

}