1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
/* $OpenBSD: pwd_check.c,v 1.11 2005/05/01 00:05:10 djm 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 <login_cap.h>
#include <signal.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(login_cap_t *lc, char *password)
{
regex_t rgx;
int i, res, min_len;
char *checker;
char *argp[] = { "sh", "-c", NULL, NULL};
int pipefds[2];
pid_t child;
uid_t uid;
gid_t gid;
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);
}
/* External password check program */
checker = login_getcapstr(lc, "passwordcheck", NULL, NULL);
/* Pipes are only used for external checker */
if (checker != NULL && pipe(pipefds) == -1) {
warn("pipe");
goto out;
}
/* Check password in low-privileged child */
switch (child = fork()) {
case -1:
warn("fork");
goto out;
case 0:
(void)signal(SIGINT, SIG_DFL);
(void)signal(SIGQUIT, SIG_DFL);
uid = getuid();
gid = getgid();
if (setresgid(gid, gid, gid) == -1) {
warn("setresgid");
exit(1);
}
if (setgroups(1, &gid) == -1) {
warn("setgroups");
exit(1);
}
if (setresuid(uid, uid, uid) == -1) {
warn("setresuid");
exit(1);
}
for (i = 0; i < sizeof(patterns) / sizeof(*patterns); i++) {
if (regcomp(&rgx, patterns[i].match,
patterns[i].flags) != 0)
continue;
res = regexec(&rgx, password, 0, NULL, 0);
regfree(&rgx);
if (res == 0) {
printf("%s\n", patterns[i].response);
exit(1);
}
}
/* If no external checker in use, accept the password */
if (checker == NULL)
exit(0);
/* Otherwise, pass control to checker program */
argp[2] = checker;
if (dup2(pipefds[0], STDIN_FILENO) == -1) {
warn("dup2");
exit(1);
}
close(pipefds[0]);
close(pipefds[1]);
if (execv(_PATH_BSHELL, argp) == -1) {
warn("exec");
exit(1);
}
/* NOTREACHED */
default:
break; /* parent continues below */
}
if (checker != NULL) {
/* Send the password to STDIN of child */
close(pipefds[0]);
write(pipefds[1], password, strlen(password) + 1);
close(pipefds[1]);
}
/* get the return value from the child */
wait(&child);
if (WIFEXITED(child) && WEXITSTATUS(child) == 0) {
if (checker != NULL)
free(checker);
return (1);
}
out:
if (checker != NULL)
free(checker);
printf("Please use a different password. Unusual capitalization,\n");
printf("control characters, or digits are suggested.\n");
return (0);
}
int
pwd_gettries(login_cap_t *lc)
{
quad_t ntries;
if ((ntries = login_getcapnum(lc, "passwordtries", -1, -1)) != -1) {
if (ntries >= 0 && ntries <= INT_MAX)
return((int)ntries);
fprintf(stderr,
"Warning: pwdtries out of range in /etc/login.conf");
}
/*
* 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. This is the historic BSD behavior.
*/
return (3);
}
|
