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
|
/*
* pam_shells module
*
* by Erik Troan <ewt@redhat.com>, Red Hat Software.
* August 5, 1996.
* This code shamelessly ripped from the pam_securetty module.
*/
#include "config.h"
#include <pwd.h>
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <syslog.h>
#include <unistd.h>
#include <security/pam_modules.h>
#include <security/pam_modutil.h>
#include <security/pam_ext.h>
#define SHELL_FILE "/etc/shells"
#define DEFAULT_SHELL "/bin/sh"
static int perform_check(pam_handle_t *pamh)
{
int retval = PAM_AUTH_ERR;
const char *userName;
const char *userShell;
char shellFileLine[256];
struct stat sb;
struct passwd * pw;
FILE * shellFile;
retval = pam_get_user(pamh, &userName, NULL);
if (retval != PAM_SUCCESS) {
return PAM_SERVICE_ERR;
}
if (!userName || (userName[0] == '\0')) {
/* Don't let them use a NULL username... */
retval = pam_get_user(pamh,&userName,NULL);
if (retval != PAM_SUCCESS)
return PAM_SERVICE_ERR;
/* It could still be NULL the second time. */
if (!userName || (userName[0] == '\0'))
return PAM_SERVICE_ERR;
}
pw = pam_modutil_getpwnam(pamh, userName);
if (pw == NULL || pw->pw_shell == NULL) {
return PAM_AUTH_ERR; /* user doesn't exist */
}
userShell = pw->pw_shell;
if (userShell[0] == '\0')
userShell = DEFAULT_SHELL;
if (stat(SHELL_FILE,&sb)) {
pam_syslog(pamh, LOG_ERR, "Cannot stat %s: %m", SHELL_FILE);
return PAM_AUTH_ERR; /* must have /etc/shells */
}
if ((sb.st_mode & S_IWOTH) || !S_ISREG(sb.st_mode)) {
pam_syslog(pamh, LOG_ERR,
"%s is either world writable or not a normal file",
SHELL_FILE);
return PAM_AUTH_ERR;
}
shellFile = fopen(SHELL_FILE,"r");
if (shellFile == NULL) { /* Check that we opened it successfully */
pam_syslog(pamh, LOG_ERR, "Error opening %s: %m", SHELL_FILE);
return PAM_SERVICE_ERR;
}
retval = 1;
while(retval && (fgets(shellFileLine, 255, shellFile) != NULL)) {
if (shellFileLine[strlen(shellFileLine) - 1] == '\n')
shellFileLine[strlen(shellFileLine) - 1] = '\0';
retval = strcmp(shellFileLine, userShell);
}
fclose(shellFile);
if (retval) {
return PAM_AUTH_ERR;
} else {
return PAM_SUCCESS;
}
}
/* --- authentication management functions (only) --- */
int pam_sm_authenticate(pam_handle_t *pamh, int flags UNUSED,
int argc UNUSED, const char **argv UNUSED)
{
return perform_check(pamh);
}
int pam_sm_setcred(pam_handle_t *pamh UNUSED, int flags UNUSED,
int argc UNUSED, const char **argv UNUSED)
{
return PAM_SUCCESS;
}
/* --- account management functions (only) --- */
int pam_sm_acct_mgmt(pam_handle_t *pamh, int flags UNUSED,
int argc UNUSED, const char **argv UNUSED)
{
return perform_check(pamh);
}
/* end of module definition */
|
