GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.bin/passwd/pwd_check.c Lines: 0 66 0.0 %
Date: 2016-12-06 Branches: 0 43 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: pwd_check.c,v 1.15 2015/12/09 19:39:10 mmcc Exp $	*/
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/*
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 * Copyright 2000 Niels Provos <provos@citi.umich.edu>
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *      This product includes software developed by Niels Provos.
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 * 4. The name of the author may not be used to endorse or promote products
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 *    derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <limits.h>
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#include <errno.h>
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#include <err.h>
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#include <regex.h>
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#include <grp.h>
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#include <paths.h>
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#include <login_cap.h>
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#include <signal.h>
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int pwd_check(login_cap_t *, char *);
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int pwd_gettries(login_cap_t *);
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struct pattern {
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	char *match;
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	int flags;
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	char *response;
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};
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struct pattern patterns[] = {
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	{
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		"^[0-9]*$",
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		REG_EXTENDED|REG_NOSUB,
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		"Please don't use all-digit passwords."
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	},
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	{
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		"^[a-z]{1,9}$",
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		REG_EXTENDED|REG_NOSUB,
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		"Please don't use an all-lower case password."
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	},
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	{
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		"^[a-z]{1,6}[0-9]+$",
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		REG_EXTENDED|REG_NOSUB|REG_ICASE,
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		"Please use a more complicated password."
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	},
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	{
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		"^([a-z][0-9]){1,4}$",
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		REG_EXTENDED|REG_NOSUB|REG_ICASE,
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		"Please use a more complicated password."
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	},
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	{
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		"^([0-9][a-z]){1,4}$",
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		REG_EXTENDED|REG_NOSUB|REG_ICASE,
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		"Please use a more complicated password."
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	}
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};
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int
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pwd_check(login_cap_t *lc, char *password)
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{
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	regex_t rgx;
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	int i, res, min_len;
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	char *checker;
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	char *argp[] = { "sh", "-c", NULL, NULL};
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	int pipefds[2];
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	pid_t child;
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	uid_t uid;
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	gid_t gid;
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	min_len = (int)login_getcapnum(lc, "minpasswordlen", 6, 6);
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	if (min_len > 0 && strlen(password) < min_len) {
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		printf("Please enter a longer password.\n");
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		return (0);
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	}
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	/* External password check program */
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	checker = login_getcapstr(lc, "passwordcheck", NULL, NULL);
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	/* Pipes are only used for external checker */
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	if (checker != NULL && pipe(pipefds) == -1) {
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		warn("pipe");
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		goto out;
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	}
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	/* Check password in low-privileged child */
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	switch (child = fork()) {
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	case -1:
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		warn("fork");
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		goto out;
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	case 0:
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		(void)signal(SIGINT, SIG_DFL);
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		(void)signal(SIGQUIT, SIG_DFL);
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		uid = getuid();
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		gid = getgid();
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		if (setresgid(gid, gid, gid) == -1) {
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			warn("setresgid");
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			exit(1);
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		}
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		if (setgroups(1, &gid) == -1) {
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			warn("setgroups");
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			exit(1);
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		}
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		if (setresuid(uid, uid, uid) == -1) {
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			warn("setresuid");
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			exit(1);
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		}
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		if (checker == NULL) {
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			if (pledge("stdio wpath cpath rpath", NULL) == -1)
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				err(1, "pledge");
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			for (i = 0; i < sizeof(patterns) / sizeof(*patterns); i++) {
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				if (regcomp(&rgx, patterns[i].match,
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				    patterns[i].flags) != 0)
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					continue;
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				res = regexec(&rgx, password, 0, NULL, 0);
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				regfree(&rgx);
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				if (res == 0) {
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					printf("%s\n", patterns[i].response);
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					exit(1);
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				}
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			}
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			/* no external checker in use, accept the password */
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			exit(0);
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		}
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		if (pledge("stdio exec wpath cpath rpath", NULL) == -1)
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			err(1, "pledge");
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		/* Otherwise, pass control to checker program */
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		argp[2] = checker;
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		if (dup2(pipefds[0], STDIN_FILENO) == -1) {
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			warn("dup2");
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			exit(1);
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		}
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		close(pipefds[0]);
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		close(pipefds[1]);
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		if (execv(_PATH_BSHELL, argp) == -1) {
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			warn("exec");
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			exit(1);
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		}
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		/* NOTREACHED */
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	default:
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		break; /* parent continues below */
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	}
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	if (checker != NULL) {
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		/* Send the password to STDIN of child */
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		close(pipefds[0]);
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		write(pipefds[1], password, strlen(password) + 1);
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		close(pipefds[1]);
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	}
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	/* get the return value from the child */
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	wait(&child);
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	if (WIFEXITED(child) && WEXITSTATUS(child) == 0) {
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		free(checker);
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		return (1);
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	}
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 out:
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	free(checker);
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	printf("Please use a different password. Unusual capitalization,\n");
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	printf("control characters, or digits are suggested.\n");
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	return (0);
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}
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int
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pwd_gettries(login_cap_t *lc)
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{
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	quad_t ntries;
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	if ((ntries = login_getcapnum(lc, "passwordtries", -1, -1)) != -1) {
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		if (ntries >= 0 && ntries <= INT_MAX)
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			return((int)ntries);
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		fprintf(stderr,
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		    "Warning: pwdtries out of range in /etc/login.conf");
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	}
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	/*
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	 * If no amount of tries is specified, return a default of 3,
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	 * meaning that after 3 attempts where the user is foiled by the
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	 * password checks, it will no longer be checked and they can set
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	 * it to whatever they like.  This is the historic BSD behavior.
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	 */
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	return (3);
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}