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/* $OpenBSD: pwd_check.c,v 1.6 2002/06/28 22:28:17 deraadt Exp $ */
/*
* Copyright 2000 Niels Provos <provos@citi.umich.edu>
* 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 Niels Provos.
* 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.
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
#include <err.h>
#include <regex.h>
#include <grp.h>
#include <paths.h>
#include <pwd.h>
#include <util.h>
#include <login_cap.h>
struct pattern {
char *match;
int flags;
char *response;
};
struct pattern patterns[] = {
{
"^[0-9]*$",
REG_EXTENDED|REG_NOSUB,
"Please don't use all-digit passwords."
},
{
"^[a-z]{1,9}$",
REG_EXTENDED|REG_NOSUB,
"Please don't use an all-lower case password."
},
{
"^[a-z]{1,6}[0-9]+$",
REG_EXTENDED|REG_NOSUB|REG_ICASE,
"Please use a more complicated password."
},
{
"^([a-z][0-9]){1,4}$",
REG_EXTENDED|REG_NOSUB|REG_ICASE,
"Please use a more complicated password."
},
{
"^([0-9][a-z]){1,4}$",
REG_EXTENDED|REG_NOSUB|REG_ICASE,
"Please use a more complicated password."
}
};
int
pwd_check(struct passwd *pwd, login_cap_t *lc, char *password)
{
regex_t rgx;
int i, res, min_len;
char *cp, option[LINE_MAX];
int pipefds[2];
min_len = (int) login_getcapnum(lc, "minpasswordlen", 6, 6);
if (min_len > 0 && strlen(password) < min_len) {
printf("Please enter a longer password.\n");
return (0);
}
for (i = 0; i < sizeof(patterns)/sizeof(struct pattern); i++) {
if (regcomp(&rgx, patterns[i].match, patterns[i].flags) != 0)
continue;
res = regexec(&rgx, password, 0, NULL, 0);
regfree(&rgx);
if (!res) {
printf("%s\nUnusual capitalization, control characters or digits are suggested.\n", patterns[i].response);
return (0);
}
}
/* Okay, now pass control to an external program */
/*
* Check login.conf, falling back onto the deprecated passwd.conf
*/
if ((cp = login_getcapstr(lc, "passwordcheck", NULL, NULL)) != NULL) {
strlcpy(option, cp, sizeof(option));
free(cp);
} else {
pw_getconf(option, LINE_MAX, pwd->pw_name, "pwdcheck");
/* Try to find an entry for the group */
if (*option == 0) {
struct group *grp;
char grpkey[LINE_MAX];
grp = getgrgid(pwd->pw_gid);
if (grp != NULL) {
snprintf(grpkey, LINE_MAX, ":%s",
grp->gr_name);
pw_getconf(option, LINE_MAX, grpkey,
"pwdcheck");
}
if (grp != NULL && *option == 0 &&
strchr(pwd->pw_name, '.') == NULL) {
snprintf(grpkey, LINE_MAX, ".%s",
grp->gr_name);
pw_getconf(option, LINE_MAX, grpkey,
"pwdcheck");
}
if (*option == 0)
pw_getconf(option, LINE_MAX, "default",
"pwdcheck");
}
}
/* If no checker is specified, we accept the password */
if (*option == 0)
return (1);
if (pipe(pipefds) == -1) {
warn("pipe");
goto out;
}
res = fork();
if (res == 0) {
char *argp[] = { "sh", "-c", NULL, NULL};
/* Drop privileges */
seteuid(getuid());
setuid(getuid());
if (dup2(pipefds[0], STDIN_FILENO) == -1)
exit(1);
close(pipefds[0]);
close(pipefds[1]);
argp[2] = option;
if (execv(_PATH_BSHELL, argp) == -1)
exit(1);
/* NOT REACHED */
} else if (res == -1) {
warn("fork");
goto out;
}
close(pipefds[0]);
/* Send the password to STDIN of child */
write(pipefds[1], password, strlen(password) + 1);
close(pipefds[1]);
/* get the return value from the child */
wait(&res);
if (WIFEXITED(res) && WEXITSTATUS(res) == 0)
return (1);
out:
printf("Please use a different password. Unusual capitalization,\n");
printf("control characters, or digits are suggested.\n");
return (0);
}
int
pwd_gettries( struct passwd *pwd, login_cap_t *lc )
{
char option[LINE_MAX];
char *ep = option;
quad_t ntries;
long lval;
/*
* Check login.conf, falling back onto the deprecated passwd.conf
*/
if ((ntries = login_getcapnum(lc, "passwordtries", -1, -1)) != -1) {
if (ntries > INT_MAX || ntries < 0) {
fprintf(stderr,
"Warning: pwdtries out of range in /etc/login.conf");
goto out;
}
return((int)ntries);
}
pw_getconf(option, LINE_MAX, pwd->pw_name, "pwdtries");
/* Try to find an entry for the group */
if (*option == 0) {
struct group *grp;
char grpkey[LINE_MAX];
grp = getgrgid(pwd->pw_gid);
if (grp != NULL) {
snprintf(grpkey, LINE_MAX, ":%s", grp->gr_name);
pw_getconf(option, LINE_MAX, grpkey, "pwdtries");
}
if (grp != NULL && *option == 0 &&
strchr(pwd->pw_name, '.') == NULL) {
snprintf(grpkey, LINE_MAX, ".%s", grp->gr_name);
pw_getconf(option, LINE_MAX, grpkey, "pwdtries");
}
if (*option == 0)
pw_getconf(option, LINE_MAX, "default", "pwdtries");
}
if (*option == 0)
goto out;
errno = 0;
lval = strtol(option, &ep, 10);
if (option[0] == '\0' || *ep != '\0') {
fprintf(stderr,
"Warning: Bad pwdtries line in /etc/passwd.conf");
goto out;
}
if ((errno == ERANGE && (lval == LONG_MAX || lval == LONG_MIN)) ||
(lval > INT_MAX || lval < 0)) {
fprintf(stderr,
"Warning: pwdtries out of range in /etc/passwd.conf");
goto out;
}
return((int) lval);
/* If no amount of tries is specified, return a default of
* 3, meaning that after 3 attempts where the user is foiled
* by the password checks, it will no longer be checked and
* they can set it to whatever they like.
*/
out:
return (3);
}
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