xref: /illumos-gate/usr/src/uts/common/syscall/access.c (revision 6a634c9d)
17c478bd9Sstevel@tonic-gate /*
27c478bd9Sstevel@tonic-gate  * CDDL HEADER START
37c478bd9Sstevel@tonic-gate  *
47c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5dd29fa4aSprabahar  * Common Development and Distribution License (the "License").
6dd29fa4aSprabahar  * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate  *
87c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate  * and limitations under the License.
127c478bd9Sstevel@tonic-gate  *
137c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate  *
197c478bd9Sstevel@tonic-gate  * CDDL HEADER END
207c478bd9Sstevel@tonic-gate  */
21*794f0adbSRoger A. Faulkner 
227c478bd9Sstevel@tonic-gate /*
23c4d3e299SBrent Paulson  * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
247c478bd9Sstevel@tonic-gate  */
257c478bd9Sstevel@tonic-gate 
267c478bd9Sstevel@tonic-gate /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
277c478bd9Sstevel@tonic-gate /*	  All Rights Reserved  	*/
287c478bd9Sstevel@tonic-gate 
297c478bd9Sstevel@tonic-gate /*
307c478bd9Sstevel@tonic-gate  * Portions of this source code were derived from Berkeley 4.3 BSD
317c478bd9Sstevel@tonic-gate  * under license from the Regents of the University of California.
327c478bd9Sstevel@tonic-gate  */
337c478bd9Sstevel@tonic-gate 
347c478bd9Sstevel@tonic-gate #include <sys/param.h>
357c478bd9Sstevel@tonic-gate #include <sys/isa_defs.h>
367c478bd9Sstevel@tonic-gate #include <sys/types.h>
377c478bd9Sstevel@tonic-gate #include <sys/sysmacros.h>
387c478bd9Sstevel@tonic-gate #include <sys/cred_impl.h>
397c478bd9Sstevel@tonic-gate #include <sys/systm.h>
407c478bd9Sstevel@tonic-gate #include <sys/errno.h>
417c478bd9Sstevel@tonic-gate #include <sys/pathname.h>
427c478bd9Sstevel@tonic-gate #include <sys/vnode.h>
437c478bd9Sstevel@tonic-gate #include <sys/uio.h>
447c478bd9Sstevel@tonic-gate #include <sys/cmn_err.h>
457c478bd9Sstevel@tonic-gate #include <sys/debug.h>
4648011479Ssn #include <sys/file.h>
47dd29fa4aSprabahar #include <fs/fs_subr.h>
4848011479Ssn #include <c2/audit.h>
49b2b3ca14SSumanth Naropanth #include <sys/fcntl.h>
507c478bd9Sstevel@tonic-gate 
517c478bd9Sstevel@tonic-gate /*
527c478bd9Sstevel@tonic-gate  * Determine accessibility of file.
537c478bd9Sstevel@tonic-gate  */
547c478bd9Sstevel@tonic-gate 
557c478bd9Sstevel@tonic-gate #define	E_OK	010	/* use effective ids */
567c478bd9Sstevel@tonic-gate #define	R_OK	004
577c478bd9Sstevel@tonic-gate #define	W_OK	002
587c478bd9Sstevel@tonic-gate #define	X_OK	001
597c478bd9Sstevel@tonic-gate 
6048011479Ssn static int
caccess(char * fname,int fmode,vnode_t * startvp)6148011479Ssn caccess(char *fname, int fmode, vnode_t *startvp)
627c478bd9Sstevel@tonic-gate {
637c478bd9Sstevel@tonic-gate 	vnode_t *vp;
647c478bd9Sstevel@tonic-gate 	cred_t *tmpcr;
657c478bd9Sstevel@tonic-gate 	int error;
667c478bd9Sstevel@tonic-gate 	int mode;
677c478bd9Sstevel@tonic-gate 	int eok;
687c478bd9Sstevel@tonic-gate 	cred_t *cr;
69dd29fa4aSprabahar 	int estale_retry = 0;
707c478bd9Sstevel@tonic-gate 
717c478bd9Sstevel@tonic-gate 	if (fmode & ~(E_OK|R_OK|W_OK|X_OK))
72*794f0adbSRoger A. Faulkner 		return (EINVAL);
737c478bd9Sstevel@tonic-gate 
747c478bd9Sstevel@tonic-gate 	mode = ((fmode & (R_OK|W_OK|X_OK)) << 6);
757c478bd9Sstevel@tonic-gate 
767c478bd9Sstevel@tonic-gate 	cr = CRED();
777c478bd9Sstevel@tonic-gate 
787c478bd9Sstevel@tonic-gate 	/* OK to use effective uid/gid, i.e., no need to crdup(CRED())? */
797c478bd9Sstevel@tonic-gate 	eok = (fmode & E_OK) ||
80d3e55dcdSgww 	    (cr->cr_uid == cr->cr_ruid && cr->cr_gid == cr->cr_rgid);
817c478bd9Sstevel@tonic-gate 
827c478bd9Sstevel@tonic-gate 	if (eok)
837c478bd9Sstevel@tonic-gate 		tmpcr = cr;
847c478bd9Sstevel@tonic-gate 	else {
857c478bd9Sstevel@tonic-gate 		tmpcr = crdup(cr);
867c478bd9Sstevel@tonic-gate 		tmpcr->cr_uid = cr->cr_ruid;
877c478bd9Sstevel@tonic-gate 		tmpcr->cr_gid = cr->cr_rgid;
887c478bd9Sstevel@tonic-gate 		tmpcr->cr_ruid = cr->cr_uid;
897c478bd9Sstevel@tonic-gate 		tmpcr->cr_rgid = cr->cr_gid;
907c478bd9Sstevel@tonic-gate 	}
917c478bd9Sstevel@tonic-gate 
927c478bd9Sstevel@tonic-gate lookup:
937a142be9SCasper H.S. Dik 	if (error = lookupnameatcred(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp,
947a142be9SCasper H.S. Dik 	    startvp, tmpcr)) {
95dd29fa4aSprabahar 		if ((error == ESTALE) && fs_need_estale_retry(estale_retry++))
967c478bd9Sstevel@tonic-gate 			goto lookup;
977c478bd9Sstevel@tonic-gate 		if (!eok)
987c478bd9Sstevel@tonic-gate 			crfree(tmpcr);
99*794f0adbSRoger A. Faulkner 		return (error);
1007c478bd9Sstevel@tonic-gate 	}
1017c478bd9Sstevel@tonic-gate 
1027c478bd9Sstevel@tonic-gate 	if (mode) {
103da6c28aaSamw 		error = VOP_ACCESS(vp, mode, 0, tmpcr, NULL);
1047c478bd9Sstevel@tonic-gate 		if (error) {
105dd29fa4aSprabahar 			if ((error == ESTALE) &&
106dd29fa4aSprabahar 			    fs_need_estale_retry(estale_retry++)) {
1077c478bd9Sstevel@tonic-gate 				VN_RELE(vp);
1087c478bd9Sstevel@tonic-gate 				goto lookup;
1097c478bd9Sstevel@tonic-gate 			}
1107c478bd9Sstevel@tonic-gate 		}
1117c478bd9Sstevel@tonic-gate 	}
1127c478bd9Sstevel@tonic-gate 
1137c478bd9Sstevel@tonic-gate 	if (!eok)
1147c478bd9Sstevel@tonic-gate 		crfree(tmpcr);
1157c478bd9Sstevel@tonic-gate 	VN_RELE(vp);
1167c478bd9Sstevel@tonic-gate 	return (error);
1177c478bd9Sstevel@tonic-gate }
11848011479Ssn 
11948011479Ssn int
faccessat(int fd,char * fname,int fmode,int flag)120b2b3ca14SSumanth Naropanth faccessat(int fd, char *fname, int fmode, int flag)
12148011479Ssn {
122*794f0adbSRoger A. Faulkner 	vnode_t *startvp;
12348011479Ssn 	int error;
12448011479Ssn 
125b2b3ca14SSumanth Naropanth 	if ((flag & ~AT_EACCESS) != 0)
126b2b3ca14SSumanth Naropanth 		return (set_errno(EINVAL));
127b2b3ca14SSumanth Naropanth 
128*794f0adbSRoger A. Faulkner 	if (fname == NULL)
129*794f0adbSRoger A. Faulkner 		return (set_errno(EFAULT));
130*794f0adbSRoger A. Faulkner 	if ((error = fgetstartvp(fd, fname, &startvp)) != 0)
131*794f0adbSRoger A. Faulkner 		return (set_errno(error));
132*794f0adbSRoger A. Faulkner 	if (AU_AUDITING() && startvp != NULL)
13348011479Ssn 		audit_setfsat_path(1);
13448011479Ssn 
135b2b3ca14SSumanth Naropanth 	/* Do not allow E_OK unless AT_EACCESS flag is set */
136b2b3ca14SSumanth Naropanth 	fmode &= ~E_OK;
137b2b3ca14SSumanth Naropanth 	if (flag & AT_EACCESS)
138b2b3ca14SSumanth Naropanth 		fmode |= E_OK;
139b2b3ca14SSumanth Naropanth 
140*794f0adbSRoger A. Faulkner 	error = caccess(fname, fmode, startvp);
141*794f0adbSRoger A. Faulkner 	if (startvp != NULL)
142*794f0adbSRoger A. Faulkner 		VN_RELE(startvp);
143*794f0adbSRoger A. Faulkner 	if (error)
144*794f0adbSRoger A. Faulkner 		return (set_errno(error));
145*794f0adbSRoger A. Faulkner 	return (0);
14648011479Ssn }
1478fd04b83SRoger A. Faulkner 
1488fd04b83SRoger A. Faulkner int
access(char * fname,int fmode)1498fd04b83SRoger A. Faulkner access(char *fname, int fmode)
1508fd04b83SRoger A. Faulkner {
1518fd04b83SRoger A. Faulkner 	return (faccessat(AT_FDCWD, fname, fmode, 0));
1528fd04b83SRoger A. Faulkner }
153