common/syscall/groups.c

/*
 * 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 (c) 1984, 1986, 1987, 1988, 1989 AT&T
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


#include <sys/param.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#include <sys/cred.h>
#include <sys/sid.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/debug.h>
#include <sys/kmem.h>
#include <sys/policy.h>

int
setgroups(int gidsetsize, gid_t *gidset)
{
    proc_t  *p;
    cred_t  *cr, *newcr;
    int i;
    int n = gidsetsize;
    int error;
    int scnt = 0;
    ksidlist_t *ksl = NULL;
    zone_t  *zone;
    struct credgrp *grps = NULL;

    /* Perform the cheapest tests before grabbing p_crlock  */
    if (n > ngroups_max || n < 0)
        return (set_errno(EINVAL));

    zone = crgetzone(CRED());
    if (n != 0) {
        const gid_t *groups;

        grps = crgrpcopyin(n, gidset);

        if (grps == NULL)
            return (set_errno(EFAULT));

        groups = crgetggroups(grps);

        for (i = 0; i < n; i++) {
            if (!VALID_GID(groups[i], zone)) {
                crgrprele(grps);
                return (set_errno(EINVAL));
            }
            if (groups[i] > MAXUID)
                scnt++;
        }
        if (scnt > 0) {
            ksl = kcrsid_gidstosids(zone, n, (gid_t *)groups);
            if (ksl == NULL) {
                crgrprele(grps);
                return (set_errno(EINVAL));
            }
        }
    }


    /*
     * Need to pre-allocate the new cred structure before acquiring
     * the p_crlock mutex.
     */
    newcr = cralloc_ksid();
    p = ttoproc(curthread);
    mutex_enter(&p->p_crlock);
retry:
    cr = p->p_cred;
    crhold(cr);
    mutex_exit(&p->p_crlock);

    if ((error = secpolicy_allow_setid(cr, -1, B_FALSE)) != 0) {
        if (grps != NULL)
            crgrprele(grps);
        if (ksl != NULL)
            ksidlist_rele(ksl);
        crfree(newcr);
        crfree(cr);
        return (set_errno(error));
    }
    mutex_enter(&p->p_crlock);
    crfree(cr);
    if (cr != p->p_cred)
        goto retry;

    crdup_to(cr, newcr);
    crsetsidlist(newcr, ksl);
    crsetcredgrp(newcr, grps);

    p->p_cred = newcr;
    crhold(newcr);          /* hold for the current thread */
    crfree(cr);         /* free the old one */
    mutex_exit(&p->p_crlock);

    /*
     * Broadcast new cred to process threads (including the current one).
     */
    crset(p, newcr);

    return (0);
}

int
getgroups(int gidsetsize, gid_t *gidset)
{
    struct cred *cr;
    int n;

    cr = curthread->t_cred;
    n = crgetngroups(cr);

    if (gidsetsize != 0) {
        if (gidsetsize < n)
            return (set_errno(EINVAL));
        if (copyout(crgetgroups(cr), gidset, n * sizeof (gid_t)))
            return (set_errno(EFAULT));
    }

    return (n);
}