/*	$OpenBSD: svc_auth_unix.c,v 1.11 2015/09/02 02:52:26 deraadt Exp $ */

/*
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * 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 the "Oracle America, 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
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 *   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.
 */

/*
 * svc_auth_unix.c
 * Handles UNIX flavor authentication parameters on the service side of rpc.
 * There are two svc auth implementations here: AUTH_UNIX and AUTH_SHORT.
 * _svcauth_unix does full blown unix style uid,gid+gids auth,
 * _svcauth_short uses a shorthand auth to index into a cache of longhand auths.
 * Note: the shorthand has been gutted for efficiency.
 */

#include <stdio.h>
#include <rpc/rpc.h>
#include <string.h>

/*
 * Unix longhand authenticator
 */
enum auth_stat
_svcauth_unix(struct svc_req *rqst, struct rpc_msg *msg)
{
	enum auth_stat stat;
	XDR xdrs;
	struct authunix_parms *aup;
	int32_t *buf;
	struct area {
		struct authunix_parms area_aup;
		char area_machname[MAX_MACHINE_NAME+1];
		int area_gids[NGRPS];
	} *area;
	u_int auth_len;
	u_int str_len, gid_len;
	u_int i;

	area = (struct area *) rqst->rq_clntcred;
	aup = &area->area_aup;
	aup->aup_machname = area->area_machname;
	aup->aup_gids = area->area_gids;
	auth_len = (u_int)msg->rm_call.cb_cred.oa_length;
	xdrmem_create(&xdrs, msg->rm_call.cb_cred.oa_base, auth_len,XDR_DECODE);
	buf = XDR_INLINE(&xdrs, auth_len);
	if (buf != NULL) {
		aup->aup_time = IXDR_GET_LONG(buf);
		str_len = IXDR_GET_U_LONG(buf);
		if (str_len > MAX_MACHINE_NAME) {
			stat = AUTH_BADCRED;
			goto done;
		}
		memcpy(aup->aup_machname, (caddr_t)buf, (u_int)str_len);
		aup->aup_machname[str_len] = 0;
		str_len = RNDUP(str_len);
		buf += str_len / sizeof (int32_t);
		aup->aup_uid = IXDR_GET_LONG(buf);
		aup->aup_gid = IXDR_GET_LONG(buf);
		gid_len = IXDR_GET_U_LONG(buf);
		if (gid_len > NGRPS) {
			stat = AUTH_BADCRED;
			goto done;
		}
		aup->aup_len = gid_len;
		for (i = 0; i < gid_len; i++) {
			aup->aup_gids[i] = IXDR_GET_LONG(buf);
		}
		/*
		 * five is the smallest unix credentials structure -
		 * timestamp, hostname len (0), uid, gid, and gids len (0).
		 */
		if ((5 + gid_len) * BYTES_PER_XDR_UNIT + str_len > auth_len) {
			stat = AUTH_BADCRED;
			goto done;
		}
	} else if (! xdr_authunix_parms(&xdrs, aup)) {
		xdrs.x_op = XDR_FREE;
		(void)xdr_authunix_parms(&xdrs, aup);
		stat = AUTH_BADCRED;
		goto done;
	}
	rqst->rq_xprt->xp_verf.oa_flavor = AUTH_NULL;
	rqst->rq_xprt->xp_verf.oa_length = 0;
	stat = AUTH_OK;
done:
	XDR_DESTROY(&xdrs);
	return (stat);
}


/*
 * Shorthand unix authenticator
 * Looks up longhand in a cache.
 */
/*ARGSUSED*/
enum auth_stat 
_svcauth_short(struct svc_req *rqst, struct rpc_msg *msg)
{
	return (AUTH_REJECTEDCRED);
}