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/* Copyright (C) 1989, 1991-2023 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <grp.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/types.h>
#include <nsswitch.h>
#include <scratch_buffer.h>
#include <config.h>
#include "../nscd/nscd-client.h"
#include "../nscd/nscd_proto.h"
/* Type of the lookup function. */
typedef enum nss_status (*initgroups_dyn_function) (const char *, gid_t,
long int *, long int *,
gid_t **, long int, int *);
static bool use_initgroups_entry;
#include "compat-initgroups.c"
static int
internal_getgrouplist (const char *user, gid_t group, long int *size,
gid_t **groupsp, long int limit)
{
#ifdef USE_NSCD
if (__nss_not_use_nscd_group > 0
&& ++__nss_not_use_nscd_group > NSS_NSCD_RETRY)
__nss_not_use_nscd_group = 0;
if (!__nss_not_use_nscd_group
&& !__nss_database_custom[NSS_DBSIDX_group])
{
int n = __nscd_getgrouplist (user, group, size, groupsp, limit);
if (n >= 0)
return n;
/* nscd is not usable. */
__nss_not_use_nscd_group = 1;
}
#endif
enum nss_status status = NSS_STATUS_UNAVAIL;
/* Never store more than the starting *SIZE number of elements. */
assert (*size > 0);
(*groupsp)[0] = group;
/* Start is one, because we have the first group as parameter. */
long int start = 1;
nss_action_list nip;
if (__nss_database_get (nss_database_initgroups, &nip)
&& nip != NULL)
{
use_initgroups_entry = true;
}
else if (__nss_database_get (nss_database_group, &nip)
&& nip != NULL)
{
use_initgroups_entry = false;
}
else
{
nip = __nss_action_parse ("files");
use_initgroups_entry = false;
}
while (nip && nip->module)
{
long int prev_start = start;
initgroups_dyn_function fct = __nss_lookup_function (nip,
"initgroups_dyn");
if (fct == NULL)
status = compat_call (nip, user, group, &start, size, groupsp,
limit, &errno);
else
status = DL_CALL_FCT (fct, (user, group, &start, size, groupsp,
limit, &errno));
/* Remove duplicates. */
long int cnt = prev_start;
while (cnt < start)
{
long int inner;
for (inner = 0; inner < prev_start; ++inner)
if ((*groupsp)[inner] == (*groupsp)[cnt])
break;
if (inner < prev_start)
(*groupsp)[cnt] = (*groupsp)[--start];
else
++cnt;
}
/* This is really only for debugging. */
if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN)
__libc_fatal ("Illegal status in internal_getgrouplist.\n");
/* For compatibility reason we will continue to look for more
entries using the next service even though data has already
been found if the nsswitch.conf file contained only a 'groups'
line and no 'initgroups' line. If the latter is available
we always respect the status. This means that the default
for successful lookups is to return. */
if ((use_initgroups_entry || status != NSS_STATUS_SUCCESS)
&& nss_next_action (nip, status) == NSS_ACTION_RETURN)
break;
nip++;
}
return start;
}
/* Store at most *NGROUPS members of the group set for USER into
*GROUPS. Also include GROUP. The actual number of groups found is
returned in *NGROUPS. Return -1 if the if *NGROUPS is too small. */
int
getgrouplist (const char *user, gid_t group, gid_t *groups, int *ngroups)
{
long int size = MAX (1, *ngroups);
gid_t *newgroups = (gid_t *) malloc (size * sizeof (gid_t));
if (__glibc_unlikely (newgroups == NULL))
/* No more memory. */
// XXX This is wrong. The user provided memory, we have to use
// XXX it. The internal functions must be called with the user
// XXX provided buffer and not try to increase the size if it is
// XXX too small. For initgroups a flag could say: increase size.
return -1;
int total = internal_getgrouplist (user, group, &size, &newgroups, -1);
memcpy (groups, newgroups, MIN (*ngroups, total) * sizeof (gid_t));
free (newgroups);
int retval = total > *ngroups ? -1 : total;
*ngroups = total;
return retval;
}
nss_interface_function (getgrouplist)
/* 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 (const char *user, gid_t group)
{
#if defined NGROUPS_MAX && NGROUPS_MAX == 0
/* No extra groups allowed. */
return 0;
#else
long int size;
gid_t *groups;
int ngroups;
int result;
/* We always use sysconf even if NGROUPS_MAX is defined. That way, the
limit can be raised in the kernel configuration without having to
recompile libc. */
long int limit = __sysconf (_SC_NGROUPS_MAX);
if (limit > 0)
/* We limit the size of the intially allocated array. */
size = MIN (limit, 64);
else
/* No fixed limit on groups. Pick a starting buffer size. */
size = 16;
groups = (gid_t *) malloc (size * sizeof (gid_t));
if (__glibc_unlikely (groups == NULL))
/* No more memory. */
return -1;
ngroups = internal_getgrouplist (user, group, &size, &groups, limit);
/* Try to set the maximum number of groups the kernel can handle. */
do
result = setgroups (ngroups, groups);
while (result == -1 && errno == EINVAL && --ngroups > 0);
free (groups);
return result;
#endif
}
nss_interface_function (initgroups)
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