xref: /illumos-gate/usr/src/uts/common/syscall/gid.c (revision ddf7fe95b8ad67aa16deb427a0b78f4dd4ff22b1)

/*
 * 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 (c) 1984, 1986, 1987, 1988, 1989 AT&T
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

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


int
setgid(gid_t gid)
{
	proc_t *p;
	int error;
	int do_nocd = 0;
	cred_t	*cr, *newcr;
	ksid_t ksid, *ksp;
	zone_t	*zone = crgetzone(CRED());


	if (!VALID_GID(gid, zone))
		return (set_errno(EINVAL));

	if (gid > MAXUID) {
		if (ksid_lookupbygid(zone, gid, &ksid) != 0)
			return (set_errno(EINVAL));
		ksp = &ksid;
	} else {
		ksp = NULL;
	}

	/*
	 * Need to pre-allocate the new cred structure before grabbing
	 * the p_crlock mutex.  We cannot hold the mutex across the
	 * secpolicy functions.
	 */
	newcr = cralloc_ksid();
	p = ttoproc(curthread);
	mutex_enter(&p->p_crlock);
retry:
	cr = p->p_cred;
	crhold(cr);
	mutex_exit(&p->p_crlock);


	if ((gid == cr->cr_rgid || gid == cr->cr_sgid) &&
	    secpolicy_allow_setid(cr, -1, B_TRUE) != 0) {
		mutex_enter(&p->p_crlock);
		crfree(cr);
		if (cr != p->p_cred)
			goto retry;
		error = 0;
		crcopy_to(cr, newcr);
		p->p_cred = newcr;
		newcr->cr_gid = gid;
		crsetsid(newcr, ksp, KSID_GROUP);
		mutex_exit(&p->p_crlock);
	} else if ((error = secpolicy_allow_setid(cr, -1, B_FALSE)) == 0) {
		mutex_enter(&p->p_crlock);
		crfree(cr);
		if (cr != p->p_cred)
			goto retry;
		/*
		 * A privileged process that makes itself look like a
		 * set-gid process must be marked to produce no core dump.
		 */
		if (cr->cr_gid != gid ||
		    cr->cr_rgid != gid ||
		    cr->cr_sgid != gid)
			do_nocd = 1;
		crcopy_to(cr, newcr);
		p->p_cred = newcr;
		newcr->cr_gid = gid;
		newcr->cr_rgid = gid;
		newcr->cr_sgid = gid;
		crsetsid(newcr, ksp, KSID_GROUP);
		mutex_exit(&p->p_crlock);
	} else {
		crfree(newcr);
		crfree(cr);
		if (ksp != NULL)
			ksid_rele(ksp);

	}

	if (error == 0) {
		if (do_nocd) {
			mutex_enter(&p->p_lock);
			p->p_flag |= SNOCD;
			mutex_exit(&p->p_lock);
		}
		crset(p, newcr);	/* broadcast to process threads */
		return (0);
	}
	return (set_errno(error));
}

int64_t
getgid(void)
{
	rval_t	r;
	cred_t	*cr;

	cr = curthread->t_cred;
	r.r_val1 = cr->cr_rgid;
	r.r_val2 = cr->cr_gid;
	return (r.r_vals);
}

int
setegid(gid_t gid)
{
	proc_t *p;
	cred_t	*cr, *newcr;
	int error = EPERM;
	int do_nocd = 0;
	ksid_t ksid, *ksp;
	zone_t	*zone = crgetzone(CRED());

	if (!VALID_GID(gid, zone))
		return (set_errno(EINVAL));

	if (gid > MAXUID) {
		if (ksid_lookupbygid(zone, gid, &ksid) != 0)
			return (set_errno(EINVAL));
		ksp = &ksid;
	} else {
		ksp = NULL;
	}
	/*
	 * Need to pre-allocate the new cred structure before grabbing
	 * the p_crlock mutex.
	 */
	newcr = cralloc_ksid();
	p = ttoproc(curthread);
	mutex_enter(&p->p_crlock);
retry:
	crhold(cr = p->p_cred);
	mutex_exit(&p->p_crlock);

	if (gid == cr->cr_rgid || gid == cr->cr_gid || gid == cr->cr_sgid ||
	    (error = secpolicy_allow_setid(cr, -1, B_FALSE)) == 0) {
		mutex_enter(&p->p_crlock);
		crfree(cr);
		if (cr != p->p_cred)
			goto retry;
		/*
		 * A privileged process that makes itself look like a
		 * set-gid process must be marked to produce no core dump.
		 */
		if (cr->cr_gid != gid && error == 0)
			do_nocd = 1;
		error = 0;
		crcopy_to(cr, newcr);
		p->p_cred = newcr;
		newcr->cr_gid = gid;
		crsetsid(newcr, ksp, KSID_GROUP);
		mutex_exit(&p->p_crlock);
	} else {
		crfree(newcr);
		crfree(cr);
		if (ksp != NULL)
			ksid_rele(ksp);
	}

	if (error == 0) {
		if (do_nocd) {
			mutex_enter(&p->p_lock);
			p->p_flag |= SNOCD;
			mutex_exit(&p->p_lock);
		}
		crset(p, newcr);	/* broadcast to process threads */
		return (0);
	}
	return (set_errno(error));
}

/*
 * Buy-back from SunOS 4.x
 *
 * Like setgid() and setegid() combined -except- that non-root users
 * can change cr_rgid to cr_gid, and the semantics of cr_sgid are
 * subtly different.
 */
int
setregid(gid_t rgid, gid_t egid)
{
	proc_t *p;
	int error = EPERM;
	int do_nocd = 0;
	cred_t *cr, *newcr;
	ksid_t ksid, *ksp;
	zone_t	*zone = crgetzone(CRED());

	if ((rgid != -1 && !VALID_GID(rgid, zone)) ||
	    (egid != -1 && !VALID_GID(egid, zone)))
		return (set_errno(EINVAL));

	if (egid != -1 && egid > MAXUID) {
		if (ksid_lookupbygid(zone, egid, &ksid) != 0)
			return (set_errno(EINVAL));
		ksp = &ksid;
	} else {
		ksp = NULL;
	}
	/*
	 * Need to pre-allocate the new cred structure before grabbing
	 * the p_crlock mutex.
	 */
	newcr = cralloc_ksid();

	p = ttoproc(curthread);
	mutex_enter(&p->p_crlock);
	cr = p->p_cred;

	if ((rgid == -1 ||
	    rgid == cr->cr_rgid || rgid == cr->cr_gid || rgid == cr->cr_sgid) &&
	    (egid == -1 || egid == cr->cr_rgid || egid == cr->cr_gid ||
	    egid == cr->cr_sgid) ||
	    (error = secpolicy_allow_setid(cr, -1, B_FALSE)) == 0) {
		crhold(cr);
		crcopy_to(cr, newcr);
		p->p_cred = newcr;

		if (egid != -1) {
			newcr->cr_gid = egid;
			crsetsid(newcr, ksp, KSID_GROUP);
		}
		if (rgid != -1)
			newcr->cr_rgid = rgid;
		/*
		 * "If the real gid is being changed, or the effective gid is
		 * being changed to a value not equal to the real gid, the
		 * saved gid is set to the new effective gid."
		 */
		if (rgid != -1 ||
		    (egid != -1 && newcr->cr_gid != newcr->cr_rgid))
			newcr->cr_sgid = newcr->cr_gid;
		/*
		 * A privileged process that makes itself look like a
		 * set-gid process must be marked to produce no core dump.
		 */
		if ((cr->cr_gid != newcr->cr_gid ||
		    cr->cr_rgid != newcr->cr_rgid ||
		    cr->cr_sgid != newcr->cr_sgid) && error == 0)
			do_nocd = 1;
		error = 0;
		crfree(cr);
	}
	mutex_exit(&p->p_crlock);

	if (error == 0) {
		if (do_nocd) {
			mutex_enter(&p->p_lock);
			p->p_flag |= SNOCD;
			mutex_exit(&p->p_lock);
		}
		crset(p, newcr);	/* broadcast to process threads */
		return (0);
	}
	crfree(newcr);
	if (ksp != NULL)
		ksid_rele(ksp);
	return (set_errno(error));
}