authunix_prot.c

/*	$NetBSD: authunix_prot.c,v 1.12 2000/01/22 22:19:17 mycroft Exp $	*/

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice, 
 *   this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of Sun Microsystems, Inc. nor the names of its 
 *   contributors may be used to endorse or promote products derived 
 *   from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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>
/*
 * authunix_prot.c
 * XDR for UNIX style authentication parameters for RPC
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 */

#include <sys/param.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/ucred.h>

#include <rpc/types.h>
#include <rpc/xdr.h>
#include <rpc/auth.h>

#include <rpc/rpc_com.h>

/* gids compose part of a credential; there may not be more than 16 of them */
#define NGRPS 16

/*
 * XDR for unix authentication parameters.
 */
bool_t
xdr_authunix_parms(XDR *xdrs, uint32_t *time, struct xucred *cred)
{
	uint32_t namelen;
	uint32_t ngroups, i;
	uint32_t junk;
	char hostbuf[MAXHOSTNAMELEN];

	if (xdrs->x_op == XDR_ENCODE) {
		/*
		 * Restrict name length to 255 according to RFC 1057.
		 */
		getcredhostname(NULL, hostbuf, sizeof(hostbuf));
		namelen = strlen(hostbuf);
		if (namelen > 255)
			namelen = 255;
	} else {
		namelen = 0;
	}
	junk = 0;

	if (!xdr_uint32_t(xdrs, time)
	    || !xdr_uint32_t(xdrs, &namelen))
		return (FALSE);

	/*
	 * Ignore the hostname on decode.
	 */
	if (xdrs->x_op == XDR_ENCODE) {
		if (!xdr_opaque(xdrs, hostbuf, namelen))
			return (FALSE);
	} else {
		xdr_setpos(xdrs, xdr_getpos(xdrs) + RNDUP(namelen));
	}

	if (!xdr_uint32_t(xdrs, &cred->cr_uid))
		return (FALSE);
	if (!xdr_uint32_t(xdrs, &cred->cr_gid))
		return (FALSE);

	if (xdrs->x_op == XDR_ENCODE) {
		/*
		 * Note that this is a `struct xucred`, which maintains its
		 * historical layout of preserving the egid in cr_ngroups and
		 * cr_groups[0] == egid.
		 */
		ngroups = cred->cr_ngroups - 1;
		if (ngroups > NGRPS)
			ngroups = NGRPS;
	}

	if (!xdr_uint32_t(xdrs, &ngroups))
		return (FALSE);
	for (i = 0; i < ngroups; i++) {
		if (i < ngroups_max) {
			if (!xdr_uint32_t(xdrs, &cred->cr_groups[i + 1]))
				return (FALSE);
		} else {
			if (!xdr_uint32_t(xdrs, &junk))
				return (FALSE);
		}
	}

	if (xdrs->x_op == XDR_DECODE) {
		if (ngroups > ngroups_max)
			cred->cr_ngroups = ngroups_max + 1;
		else
			cred->cr_ngroups = ngroups + 1;
	}

	return (TRUE);
}