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
|
/* Copyright (C) 1989, 91, 93, 96, 97, 98 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <alloca.h>
#include <errno.h>
#include <grp.h>
#include <limits.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <nsswitch.h>
/* Type of the lookup function. */
typedef enum nss_status (*initgroups_function) (const char *, gid_t,
long int *, long int *,
gid_t *, long int, int *);
/* Prototype for the setgrent functions we use here. */
typedef enum nss_status (*set_function) (void);
/* Prototype for the endgrent functions we use here. */
typedef enum nss_status (*end_function) (void);
/* Prototype for the setgrent functions we use here. */
typedef enum nss_status (*get_function) (struct group *, char *,
size_t, int *);
/* The lookup function for the first entry of this service. */
extern int __nss_group_lookup (service_user **nip, const char *name,
void **fctp);
extern void *__nss_lookup_function (service_user *ni, const char *fct_name);
extern service_user *__nss_group_database;
static enum nss_status
compat_call (service_user *nip, const char *user, gid_t group, long int *start,
long int *size, gid_t *groups, long int limit, int *errnop)
{
struct group grpbuf, *g;
size_t buflen = sysconf (_SC_GETPW_R_SIZE_MAX);
char *tmpbuf;
enum nss_status status;
set_function setgrent_fct;
get_function getgrent_fct;
end_function endgrent_fct;
setgrent_fct = __nss_lookup_function (nip, "setgrent");
status = (*setgrent_fct) ();
if (status != NSS_STATUS_SUCCESS)
return status;
getgrent_fct = __nss_lookup_function (nip, "getgrent_r");
endgrent_fct = __nss_lookup_function (nip, "endgrent");
tmpbuf = __alloca (buflen);
do
{
while ((status =
(*getgrent_fct) (&grpbuf, tmpbuf, buflen, errnop)) ==
NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
{
buflen *= 2;
tmpbuf = __alloca (buflen);
}
if (status != NSS_STATUS_SUCCESS)
goto done;
g = &grpbuf;
if (g->gr_gid != group)
{
char **m;
for (m = g->gr_mem; *m != NULL; ++m)
if (strcmp (*m, user) == 0)
{
/* Matches user. Insert this group. */
if (*start == *size && limit <= 0)
{
/* Need a bigger buffer. */
groups = realloc (groups, *size * sizeof (*groups));
if (groups == NULL)
goto done;
*size *= 2;
}
groups[*start] = g->gr_gid;
*start += 1;
if (*start == limit)
/* Can't take any more groups; stop searching. */
goto done;
break;
}
}
}
while (status == NSS_STATUS_SUCCESS);
done:
(*endgrent_fct) ();
return NSS_STATUS_SUCCESS;
}
/* Initialize the group set for the current user
by reading the group database and using all groups
of which USER is a member. Also include GROUP. */
int
initgroups (user, group)
const char *user;
gid_t group;
{
#if defined NGROUPS_MAX && NGROUPS_MAX == 0
/* No extra groups allowed. */
return 0;
#else
service_user *nip = NULL;
initgroups_function fct;
enum nss_status status = NSS_STATUS_UNAVAIL;
int no_more;
/* Start is one, because we have the first group as parameter. */
long int start = 1;
long int size;
gid_t *groups;
#ifdef NGROUPS_MAX
# define limit NGROUPS_MAX
size = limit;
#else
long int limit = sysconf (_SC_NGROUPS_MAX);
if (limit > 0)
size = limit;
else
/* No fixed limit on groups. Pick a starting buffer size. */
size = 16;
#endif
groups = malloc (size * sizeof (gid_t *));
groups[0] = group;
if (__nss_group_database != NULL)
{
no_more = 0;
nip = __nss_group_database;
}
else
no_more = __nss_database_lookup ("group", NULL,
"compat [NOTFOUND=return] files", &nip);
while (! no_more)
{
fct = __nss_lookup_function (nip, "initgroups");
if (fct == NULL)
status = compat_call (nip, user, group, &start, &size, groups,
limit, &errno);
else
status = (*fct) (user, group, &start, &size, groups, limit,
&errno);
if (nip->next == NULL)
no_more = -1;
else
nip = nip->next;
}
return setgroups (start, groups);
#endif
}
|
