/*	$OpenBSD: util.c,v 1.8 2000/10/13 13:22:02 niklas Exp $	*/
/*	$EOM: util.c,v 1.17 2000/10/13 13:04:16 ho Exp $	*/

/*
 * Copyright (c) 1998, 1999 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 2000 Håkan Olsson.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Ericsson Radio Systems.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "sysdep.h"

#include "log.h"
#include "message.h"
#include "sysdep.h"
#include "transport.h"
#include "util.h"

/*
 * This is set to true in case of regression-test mode, when it will
 * cause predictable random numbers be generated.
 */
int regrand = 0;

/*
 * XXX These might be turned into inlines or macros, maybe even
 * machine-dependent ones, for performance reasons.
 */
u_int16_t
decode_16 (u_int8_t *cp)
{
  return cp[0] << 8 | cp[1];
}

u_int32_t
decode_32 (u_int8_t *cp)
{
  return cp[0] << 24 | cp[1] << 16 | cp[2] << 8 | cp[3];
}

void
encode_16 (u_int8_t *cp, u_int16_t x)
{
  *cp++ = x >> 8;
  *cp = x & 0xff;
}

void
encode_32 (u_int8_t *cp, u_int32_t x)
{
  *cp++ = x >> 24;
  *cp++ = (x >> 16) & 0xff;
  *cp++ = (x >> 8) & 0xff;
  *cp = x & 0xff;
}

/* Check a buffer for all zeroes.  */
int
zero_test (const u_int8_t *p, size_t sz)
{
  while (sz-- > 0)
    if (*p++ != 0)
      return 0;
  return 1;
}

/*
 * Generate a random data, len bytes long.
 */
u_int8_t *
getrandom (u_int8_t *buf, size_t len)
{
  u_int32_t tmp = 0;
  int i;

  for (i = 0; i < len; i++)
    {
      if (i % sizeof tmp == 0)
	tmp = sysdep_random ();

      buf[i] = tmp & 0xff;
      tmp >>= 8;
    }

  return buf;
}

static __inline int
hex2nibble (char c)
{
  if (c >= '0' && c <= '9')
    return c - '0';
  if (c >= 'a' && c <= 'f')
    return c - 'a' + 10;
  if (c >= 'A' && c <= 'F')
    return c - 'A' + 10;
  return -1;
}

/*
 * Convert hexadecimal string in S to raw binary buffer at BUF sized SZ
 * bytes.  Return 0 if everything is OK, -1 otherwise.
 */
int
hex2raw (char *s, u_int8_t *buf, size_t sz)
{
  char *p;
  u_int8_t *bp;
  int tmp;

  if (strlen (s) > sz * 2)
    return -1;
  for (p = s + strlen (s) - 1, bp = &buf[sz - 1]; bp >= buf; bp--)
    {
      *bp = 0;
      if (p >= s)
	{
	  tmp = hex2nibble (*p--);
	  if (tmp == -1)
	    return -1;
	  *bp = tmp;
	}
      if (p >= s)
	{
	  tmp = hex2nibble (*p--);
	  if (tmp == -1)
	    return -1;
	  *bp |= tmp << 4;
	}
    }
  return 0;
}

/*
 * Perform sanity check on files containing secret information.
 * Returns -1 on failure, 0 otherwise.
 * Also, if *file_size != NULL, store file size here.
 */
int
check_file_secrecy (char *name, off_t *file_size)
{
  struct stat st;
  
  if (lstat (name, &st) == -1)
    {
      log_error ("check_file_secrecy: lstat (\"%s\") failed", name);
      return -1;
    }
  if (st.st_uid != geteuid () && st.st_uid != getuid ())
    {
      log_print ("check_file_secrecy: "
		 "not loading %s - file owner is not process user", name);
      return -1;
    }
  if ((st.st_mode & (S_IRWXG | S_IRWXO)) != 0)
    {
      log_print ("conf_file_secrecy: not loading %s - too open permissions",
		 name);
      return -1;
    }
  
  if (file_size)
    *file_size = st.st_size;

  return 0;
}