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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
* Copyright 2020 Joyent, Inc.
*/
/* Copyright (c) 1988 AT&T */
/* All Rights Reserved */
#pragma weak _initgroups = initgroups
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <grp.h>
#include <limits.h>
#include <sys/debug.h>
#include <sys/types.h>
#include <sys/param.h>
#include <unistd.h>
/* Private interface to the groups code in getgrnam.c */
extern int _getgroupsbymember(const char *, gid_t[], int, int);
int
initgroups(const char *uname, gid_t agroup)
{
gid_t *groups;
long ngroups_max;
int ngroups;
int errsave, retsave;
if ((ngroups_max = sysconf(_SC_NGROUPS_MAX)) < 0) {
/* ==== Hope sysconf() set errno to something sensible */
return (-1);
}
/*
* ngroups_max is the maximum number of supplemental groups per
* process. if no supplemental groups are allowed, we're done.
*/
if (ngroups_max == 0)
return (0);
if ((groups = (gid_t *)calloc(ngroups_max, sizeof (gid_t))) == 0) {
errno = ENOMEM;
return (-1);
}
groups[0] = agroup;
ngroups = _getgroupsbymember(uname, groups, (int)ngroups_max,
(agroup <= MAXUID) ? 1 : 0);
if (ngroups < 0) {
/* XXX -- man page does not define a value for errno in */
/* this case. Should be looked into sometime. */
free(groups);
return (-1);
}
retsave = setgroups(ngroups, groups);
errsave = errno;
free(groups);
errno = errsave;
return (retsave);
}
int
getgrouplist(const char *uname, gid_t agroup, gid_t *groups, int *ngroups)
{
gid_t *grouplist = NULL;
gid_t *grpptr;
long ngroups_max;
int sz, ret;
/*
* We require sysconf(_SC_NGROUPS_MAX) either returns a sane value (>0)
* or fails. If it returns 0, something has gone horribly, horribly
* wrong.
*/
ngroups_max = sysconf(_SC_NGROUPS_MAX);
if (ngroups_max > INT_MAX)
ngroups_max = INT_MAX;
else if (ngroups_max < 0)
return (-1);
VERIFY3S(ngroups_max, >, 0);
/*
* The documented behavior of getgrouplist(3C) on other platforms
* (e.g. Linux and FreeBSD) do not list any failures other than
* 'groups is too small'. However, examination of some popular
* implementations of getgrouplist on those platforms (e.g. glibc and
* musl -- both appear to share the same man page for getgrouplist(3))
* show that they can in fact fail for other reasons (e.g. ENOMEM,
* EIO).
*
* As such, we don't attempt to catch and deal with any underlying
* errors here. Instead, any underlying errors cause getgrouplist(3C)
* to fail, and any errno value set is left unmodified for examination
* by the caller.
*
* One small complication is that the internal _getgroupsbymember()
* itself doesn't provide any way to report back if the buffer supplied
* to _getgroupsbymember() is too small. Instead, we always supply
* a buffer large enough to hold _SC_NGROUPS_MAX entries -- either
* by allocating one ourselves or using the user supplied buffer if
* sufficiently large.
*
* The system behavior is undefined for any user in more groups than
* _SC_NGROUPS_MAX -- initgroups(3C) for example just ignores any
* excess groups (and which _SC_NGROUPS_MAX sized subset of groups end
* up being set as the secondary groups is non-deterministic), so this
* seems reasonable. Modifying _getgroupsbymember() would require
* modification of the NSS code (due to the pervasive special handling
* of _getgroupsbymember() in the NSS code) as well as modification of
* all NSS backends that implement it. As there are at least a few
* known third party NSS backends, we've opted to avoid doing this
* for now.
*/
if ((ngroups == NULL) || (*ngroups <= 0) || (groups == NULL)) {
*ngroups = ngroups_max;
errno = EINVAL;
return (-1);
}
if (*ngroups < ngroups_max) {
/*
* The caller's buffer might be too small, try to use our own
* buffer instead.
*/
grouplist = calloc(ngroups_max, sizeof (gid_t));
if (grouplist == NULL)
return (-1);
grpptr = grouplist;
sz = ngroups_max;
} else {
/* The caller's buffer is large enough, so use it */
grpptr = groups;
sz = *ngroups;
}
/*
* Always add agroup as the first member -- it should always appear
* in the resulting list of groups, and this allows the backends to
* skip adding it.
*/
grpptr[0] = agroup;
ret = _getgroupsbymember(uname, grpptr, sz, 1);
/*
* We passed in 1 group entry. We should at minimum get 1 entry back
* from _getgroupsbymember(). If we don't, there is a bug in the NSS
* code or a backend. Since the return value is used to size a copy
* further below, we hard fail (abort) here if we get back an
* impossible value so we're not traipsing all over memory (which would
* just make debugging any such problem all the more difficult).
*/
VERIFY3S(ret, >, 0);
/*
* If we used the caller's buffer, it means its size was >= ngroups_max
* entries, and we're done.
*/
if (grpptr == groups) {
/* Set *ngroups to the number of entries in groups */
*ngroups = ret;
return (ret);
}
/* We verified earlier *ngroups > 0 */
if (ret < *ngroups) {
/* Copy as many gids that will fit */
(void) memcpy(groups, grpptr, *ngroups * sizeof (gid_t));
*ngroups = ret;
ret = -1;
errno = ERANGE;
} else {
(void) memcpy(groups, grpptr, ret * sizeof (gid_t));
*ngroups = ret;
}
free(grouplist);
return (ret);
}
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