/* $NetBSD: grutil.c,v 1.4 2014/06/23 06:57:31 shm Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Brian Ginsbach.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: grutil.c,v 1.4 2014/06/23 06:57:31 shm Exp $");
#include <sys/param.h>
#include <err.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <util.h>
#ifdef LOGIN_CAP
#include <login_cap.h>
#endif
#include "grutil.h"
typedef enum {
ADDGRP_NOERROR = 0, /* must be zero */
ADDGRP_EMALLOC = 1,
ADDGRP_EGETGROUPS = 2,
ADDGRP_ESETGROUPS = 3
} addgrp_ret_t;
static void
free_groups(void *groups)
{
int oerrno;
oerrno = errno;
free(groups);
errno = oerrno;
}
static addgrp_ret_t
alloc_groups(int *ngroups, gid_t **groups, int *ngroupsmax)
{
*ngroupsmax = (int)sysconf(_SC_NGROUPS_MAX);
if (*ngroupsmax < 0)
*ngroupsmax = NGROUPS_MAX;
*groups = malloc(*ngroupsmax * sizeof(**groups));
if (*groups == NULL)
return ADDGRP_EMALLOC;
*ngroups = getgroups(*ngroupsmax, *groups);
if (*ngroups == -1) {
free_groups(*groups);
return ADDGRP_ESETGROUPS;
}
return ADDGRP_NOERROR;
}
static addgrp_ret_t
addgid(gid_t *groups, int ngroups, int ngroupsmax, gid_t gid, int makespace)
{
int i;
/* search for gid in supplemental group list */
for (i = 0; i < ngroups && groups[i] != gid; i++)
continue;
/* add the gid to the supplemental group list */
if (i == ngroups) {
if (ngroups < ngroupsmax)
groups[ngroups++] = gid;
else { /*
* setgroups(2) will fail with errno = EINVAL
* if ngroups > nmaxgroups. If makespace is
* set, replace the last group with the new
* one. Otherwise, fail the way setgroups(2)
* would if we passed the larger groups array.
*/
if (makespace) {
/*
* Find a slot that doesn't contain
* the primary group.
*/
struct passwd *pwd;
gid_t pgid;
pwd = getpwuid(getuid());
if (pwd == NULL)
goto error;
pgid = pwd->pw_gid;
for (i = ngroupsmax - 1; i >= 0; i--)
if (groups[i] != pgid)
break;
if (i < 0)
goto error;
groups[i] = gid;
}
else {
error:
errno = EINVAL;
return ADDGRP_ESETGROUPS;
}
}
if (setgroups(ngroups, groups) < 0)
return ADDGRP_ESETGROUPS;
}
return ADDGRP_NOERROR;
}
static addgrp_ret_t
addgrp(gid_t newgid, int makespace)
{
int ngroups, ngroupsmax;
addgrp_ret_t rval;
gid_t *groups;
gid_t oldgid;
oldgid = getgid();
if (oldgid == newgid) /* nothing to do */
return ADDGRP_NOERROR;
rval = alloc_groups(&ngroups, &groups, &ngroupsmax);
if (rval != ADDGRP_NOERROR)
return rval;
/*
* BSD based systems normally have the egid in the supplemental
* group list.
*/
#if (defined(BSD) && BSD >= 199306)
/*
* According to POSIX/XPG6:
* On system where the egid is normally in the supplemental group list
* (or whenever the old egid actually is in the supplemental group
* list):
* o If the new egid is in the supplemental group list,
* just change the egid.
* o If the new egid is not in the supplemental group list,
* add the new egid to the list if there is room.
*/
rval = addgid(groups, ngroups, ngroupsmax, newgid, makespace);
#else
/*
* According to POSIX/XPG6:
* On systems where the egid is not normally in the supplemental group
* list (or whenever the old egid is not in the supplemental group
* list):
* o If the new egid is in the supplemental group list, delete
* it from the list.
* o If the old egid is not in the supplemental group list,
* add the old egid to the list if there is room.
*/
{
int i;
/* search for new egid in supplemental group list */
for (i = 0; i < ngroups && groups[i] != newgid; i++)
continue;
/* remove new egid from supplemental group list */
if (i != ngroups)
for (--ngroups; i < ngroups; i++)
groups[i] = groups[i + 1];
rval = addgid(groups, ngroups, ngroupsmax, oldgid, makespace);
}
#endif
free_groups(groups);
return rval;
}
/*
* If newgrp fails, it returns (gid_t)-1 and the errno variable is
* set to:
* [EINVAL] Unknown group.
* [EPERM] Bad password.
*/
static gid_t
newgrp(const char *gname, struct passwd *pwd, uid_t ruid, const char *prompt)
{
struct group *grp;
char **ap;
char *p;
gid_t *groups;
int ngroups, ngroupsmax;
if (gname == NULL)
return pwd->pw_gid;
grp = getgrnam(gname);
#ifdef GRUTIL_ACCEPT_GROUP_NUMBERS
if (grp == NULL) {
gid_t gid;
if (*gname != '-') {
gid = (gid_t)strtol(gname, &p, 10);
if (*p == '\0')
grp = getgrgid(gid);
}
}
#endif
if (grp == NULL) {
errno = EINVAL;
return (gid_t)-1;
}
if (ruid == 0 || pwd->pw_gid == grp->gr_gid)
return grp->gr_gid;
if (alloc_groups(&ngroups, &groups, &ngroupsmax) == ADDGRP_NOERROR) {
int i;
for (i = 0; i < ngroups; i++)
if (groups[i] == grp->gr_gid) {
free_groups(groups);
return grp->gr_gid;
}
free_groups(groups);
}
/*
* Check the group membership list in case the groups[] array
* was maxed out or the user has been added to it since login.
*/
for (ap = grp->gr_mem; *ap != NULL; ap++)
if (strcmp(*ap, pwd->pw_name) == 0)
return grp->gr_gid;
if (*grp->gr_passwd != '\0') {
p = getpass(prompt);
if (strcmp(grp->gr_passwd, crypt(p, grp->gr_passwd)) == 0) {
(void)memset(p, '\0', _PASSWORD_LEN);
return grp->gr_gid;
}
(void)memset(p, '\0', _PASSWORD_LEN);
}
errno = EPERM;
return (gid_t)-1;
}
#ifdef GRUTIL_SETGROUPS_MAKESPACE
# define ADDGRP_MAKESPACE 1
#else
# define ADDGRP_MAKESPACE 0
#endif
#ifdef GRUTIL_ALLOW_GROUP_ERRORS
# define maybe_exit(e)
#else
# define maybe_exit(e) exit(e);
#endif
void
addgroup(
#ifdef LOGIN_CAP
login_cap_t *lc,
#endif
const char *gname, struct passwd *pwd, uid_t ruid, const char *prompt)
{
pwd->pw_gid = newgrp(gname, pwd, ruid, prompt);
if (pwd->pw_gid == (gid_t)-1) {
switch (errno) {
case EINVAL:
warnx("Unknown group `%s'", gname);
maybe_exit(EXIT_FAILURE);
break;
case EPERM: /* password failure */
warnx("Sorry");
maybe_exit(EXIT_FAILURE);
break;
default: /* XXX - should never happen */
err(EXIT_FAILURE, "unknown error");
break;
}
pwd->pw_gid = getgid();
}
switch (addgrp(pwd->pw_gid, ADDGRP_MAKESPACE)) {
case ADDGRP_NOERROR:
break;
case ADDGRP_EMALLOC:
err(EXIT_FAILURE, "malloc");
break;
case ADDGRP_EGETGROUPS:
err(EXIT_FAILURE, "getgroups");
break;
case ADDGRP_ESETGROUPS:
switch(errno) {
case EINVAL:
warnx("setgroups: ngroups > ngroupsmax");
maybe_exit(EXIT_FAILURE);
break;
case EPERM:
case EFAULT:
default:
warn("setgroups");
maybe_exit(EXIT_FAILURE);
break;
}
break;
}
#ifdef LOGIN_CAP
if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGID) == -1)
err(EXIT_FAILURE, "setting user context");
#else
if (setgid(pwd->pw_gid) == -1)
err(EXIT_FAILURE, "setgid");
#endif
}
