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
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
/* PAM Make Home Dir module
This module will create a users home directory if it does not exist
when the session begins. This allows users to be present in central
database (such as nis, kerb or ldap) without using a distributed
file system or pre-creating a large number of directories.
Here is a sample /etc/pam.d/login file for Debian GNU/Linux
2.1:
auth requisite pam_securetty.so
auth sufficient pam_ldap.so
auth required pam_unix.so
auth optional pam_group.so
auth optional pam_mail.so
account requisite pam_time.so
account sufficient pam_ldap.so
account required pam_unix.so
session required pam_mkhomedir.so skel=/etc/skel/ umask=0022
session required pam_unix.so
session optional pam_lastlog.so
password required pam_unix.so
Released under the GNU LGPL version 2 or later
Copyright (c) Red Hat, Inc. 2009
Originally written by Jason Gunthorpe <jgg@debian.org> Feb 1999
Structure taken from pam_lastlogin by Andrew Morgan
<morgan@parc.power.net> 1996
*/
#include "config.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <signal.h>
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
#include <security/pam_modutil.h>
#include <security/pam_ext.h>
#include "pam_cc_compat.h"
#include "pam_inline.h"
/* argument parsing */
#define MKHOMEDIR_DEBUG 020 /* be verbose about things */
#define MKHOMEDIR_QUIET 040 /* keep quiet about things */
struct options_t {
int ctrl;
const char *umask;
const char *skeldir;
};
typedef struct options_t options_t;
static void
_pam_parse (const pam_handle_t *pamh, int flags, int argc, const char **argv,
options_t *opt)
{
opt->ctrl = 0;
opt->umask = "0022";
opt->skeldir = "/etc/skel";
/* does the application require quiet? */
if ((flags & PAM_SILENT) == PAM_SILENT)
opt->ctrl |= MKHOMEDIR_QUIET;
/* step through arguments */
for (; argc-- > 0; ++argv)
{
const char *str;
if (!strcmp(*argv, "silent")) {
opt->ctrl |= MKHOMEDIR_QUIET;
} else if (!strcmp(*argv, "debug")) {
opt->ctrl |= MKHOMEDIR_DEBUG;
} else if ((str = pam_str_skip_prefix(*argv, "umask=")) != NULL) {
opt->umask = str;
} else if ((str = pam_str_skip_prefix(*argv, "skel=")) != NULL) {
opt->skeldir = str;
} else {
pam_syslog(pamh, LOG_ERR, "unknown option: %s", *argv);
}
}
}
/* Do the actual work of creating a home dir */
static int
create_homedir (pam_handle_t *pamh, options_t *opt,
const char *user, const char *dir)
{
int retval, child;
struct sigaction newsa, oldsa;
/* Mention what is happening, if the notification fails that is OK */
if (!(opt->ctrl & MKHOMEDIR_QUIET))
pam_info(pamh, _("Creating directory '%s'."), dir);
D(("called."));
/*
* This code arranges that the demise of the child does not cause
* the application to receive a signal it is not expecting - which
* may kill the application or worse.
*/
memset(&newsa, '\0', sizeof(newsa));
newsa.sa_handler = SIG_DFL;
sigaction(SIGCHLD, &newsa, &oldsa);
if (opt->ctrl & MKHOMEDIR_DEBUG) {
pam_syslog(pamh, LOG_DEBUG, "Executing mkhomedir_helper.");
}
/* fork */
child = fork();
if (child == 0) {
static char *envp[] = { NULL };
const char *args[] = { NULL, NULL, NULL, NULL, NULL };
if (pam_modutil_sanitize_helper_fds(pamh, PAM_MODUTIL_PIPE_FD,
PAM_MODUTIL_PIPE_FD,
PAM_MODUTIL_PIPE_FD) < 0)
_exit(PAM_SYSTEM_ERR);
/* exec the mkhomedir helper */
args[0] = MKHOMEDIR_HELPER;
args[1] = user;
args[2] = opt->umask;
args[3] = opt->skeldir;
DIAG_PUSH_IGNORE_CAST_QUAL;
execve(MKHOMEDIR_HELPER, (char **)args, envp);
DIAG_POP_IGNORE_CAST_QUAL;
/* should not get here: exit with error */
D(("helper binary is not available"));
_exit(PAM_SYSTEM_ERR);
} else if (child > 0) {
int rc;
while ((rc=waitpid(child, &retval, 0)) < 0 && errno == EINTR);
if (rc < 0) {
pam_syslog(pamh, LOG_ERR, "waitpid failed: %m");
retval = PAM_SYSTEM_ERR;
} else if (!WIFEXITED(retval)) {
pam_syslog(pamh, LOG_ERR, "mkhomedir_helper abnormal exit: %d", retval);
retval = PAM_SYSTEM_ERR;
} else {
retval = WEXITSTATUS(retval);
}
} else {
D(("fork failed"));
pam_syslog(pamh, LOG_ERR, "fork failed: %m");
retval = PAM_SYSTEM_ERR;
}
sigaction(SIGCHLD, &oldsa, NULL); /* restore old signal handler */
if (opt->ctrl & MKHOMEDIR_DEBUG) {
pam_syslog(pamh, LOG_DEBUG, "mkhomedir_helper returned %d", retval);
}
if (retval != PAM_SUCCESS && !(opt->ctrl & MKHOMEDIR_QUIET)) {
pam_error(pamh, _("Unable to create and initialize directory '%s'."),
dir);
}
D(("returning %d", retval));
return retval;
}
/* --- authentication management functions (only) --- */
int
pam_sm_open_session (pam_handle_t *pamh, int flags, int argc,
const char **argv)
{
int retval;
options_t opt;
const void *user;
const struct passwd *pwd;
struct stat St;
/* Parse the flag values */
_pam_parse(pamh, flags, argc, argv, &opt);
/* Determine the user name so we can get the home directory */
retval = pam_get_item(pamh, PAM_USER, &user);
if (retval != PAM_SUCCESS || user == NULL || *(const char *)user == '\0')
{
pam_syslog(pamh, LOG_NOTICE, "Cannot obtain the user name.");
return PAM_USER_UNKNOWN;
}
/* Get the password entry */
pwd = pam_modutil_getpwnam (pamh, user);
if (pwd == NULL)
{
pam_syslog(pamh, LOG_NOTICE, "User unknown.");
D(("couldn't identify user %s", user));
return PAM_USER_UNKNOWN;
}
/* Stat the home directory, if something exists then we assume it is
correct and return a success*/
if (stat(pwd->pw_dir, &St) == 0) {
if (opt.ctrl & MKHOMEDIR_DEBUG) {
pam_syslog(pamh, LOG_DEBUG, "Home directory %s already exists.",
pwd->pw_dir);
}
return PAM_SUCCESS;
}
return create_homedir(pamh, &opt, user, pwd->pw_dir);
}
/* Ignore */
int pam_sm_close_session (pam_handle_t * pamh UNUSED, int flags UNUSED,
int argc UNUSED, const char **argv UNUSED)
{
return PAM_SUCCESS;
}
|