/*
 * Copyright (c) 1990 - 1994, Julianne Frances Haugh
 * Copyright (c) 1996 - 2000, Marek Michałkiewicz
 * Copyright (c) 2001 - 2005, Tomasz Kłoczko
 * Copyright (c) 2005 - 2008, Nicolas François
 * 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. The name of the copyright holders or contributors may not be used to
 *    endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``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 COPYRIGHT
 * HOLDERS OR CONTRIBUTORS 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.
 */

/*
 * is_valid_user_name(), is_valid_group_name() - check the new user/group
 * name for validity;
 * return values:
 *   true  - OK
 *   false - bad name
 */

#include <config.h>

#ident "$Id$"

#include <ctype.h>
#include "defines.h"
#include "chkname.h"

int allow_bad_names = false;

static bool is_valid_name (const char *name)
{
	if (allow_bad_names) {
		return true;
	}

#if 0
	/*
	 * User/group names must match [a-z_][a-z0-9_-]*[$]
	 */

	if (('\0' == *name) ||
	    !((('a' <= *name) && ('z' >= *name)) || ('_' == *name))) {
		return false;
	}

	while ('\0' != *++name) {
		if (!(( ('a' <= *name) && ('z' >= *name) ) ||
		      ( ('0' <= *name) && ('9' >= *name) ) ||
		      ('_' == *name) ||
		      ('-' == *name) ||
		      ( ('$' == *name) && ('\0' == *(name + 1)) )
		     )) {
			return false;
		}
	}
#endif
	/*
	 * POSIX indicate that usernames are composed of characters from the
	 * portable filename character set [A-Za-z0-9._-], and that the hyphen
	 * should not be used as the first character of a portable user name.
	 *
	 * Allow more relaxed user/group names in Debian -- ^[^-~+:,\s][^:,\s]*$
	 */
	bool is_numeric = true;
	bool is_hex = true;
	bool is_octal = true;
	/*
	 * We skip the hex and octal checks for the first two characters in the
	 * loop, and inspect them individually before the loop starts. This
	 * checks for "0x" and "0o" at the beginning of the username while still
	 * treating "x" and "o" as non-numeric characters in all other scenarios
	 */
	int chars_checked = 0;

	if (   ('\0' == *name)
	    || ('-'  == *name)
	    || ('~'  == *name)
	    || ('+'  == *name)) {
		return false;
	}
	/* if the username does not start with "0x" it is not hexadecimal */
	if (*name != '0' || *(name + 1) != 'x') {
		is_hex = false;
	}
	/* if the username does not start with "0o" it is not octal */
	if (*name != '0' || *(name + 1) != 'o') {
		is_octal = false;
	}
	do {
		if ((':' == *name) || (',' == *name) || isspace(*name)) {
			return false;
		}
		if ((*name < '0' || *name > '9')) {
			is_numeric = false;
		}
		if ((*name < '0' || *name > '9') &&
		    (*name < 'A' || *name > 'F') &&
		    (*name < 'a' || *name > 'f') &&
		    chars_checked >= 2) {
			is_hex = false;
		}
		if ((*name < '0' || *name > '7') && chars_checked >= 2) {
			is_octal = false;
		}
		chars_checked++;
		name++;
	} while ('\0' != *name);

	if (is_numeric || is_hex || is_octal) {
		return false;
	}
	return true;
}

bool is_valid_user_name (const char *name)
{
	/*
	 * User names are limited by whatever utmp can
	 * handle.
	 */
	if (strlen (name) > USER_NAME_MAX_LENGTH) {
		return false;
	}

	return is_valid_name (name);
}

bool is_valid_group_name (const char *name)
{
	/*
	 * Arbitrary limit for group names.
	 * HP-UX 10 limits to 16 characters
	 */
	if (   (GROUP_NAME_MAX_LENGTH > 0)
	    && (strlen (name) > GROUP_NAME_MAX_LENGTH)) {
		return false;
	}

	return is_valid_name (name);
}

