1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
27 /* All Rights Reserved */
28
29 /*
30 * Portions of this source code were derived from Berkeley 4.3 BSD
31 * under license from the Regents of the University of California.
32 */
33
34 #include <sys/param.h>
35 #include <sys/isa_defs.h>
36 #include <sys/types.h>
37 #include <sys/sysmacros.h>
38 #include <sys/cred_impl.h>
39 #include <sys/systm.h>
40 #include <sys/errno.h>
41 #include <sys/pathname.h>
42 #include <sys/vnode.h>
43 #include <sys/uio.h>
44 #include <sys/cmn_err.h>
45 #include <sys/debug.h>
46 #include <sys/file.h>
47 #include <fs/fs_subr.h>
48 #include <c2/audit.h>
49 #include <sys/fcntl.h>
50
51 /*
52 * Determine accessibility of file.
53 */
54
55 #define E_OK 010 /* use effective ids */
56 #define R_OK 004
57 #define W_OK 002
58 #define X_OK 001
59
60 static int
caccess(char * fname,int fmode,vnode_t * startvp)61 caccess(char *fname, int fmode, vnode_t *startvp)
62 {
63 vnode_t *vp;
64 cred_t *tmpcr;
65 int error;
66 int mode;
67 int eok;
68 cred_t *cr;
69 int estale_retry = 0;
70
71 if (fmode & ~(E_OK|R_OK|W_OK|X_OK))
72 return (EINVAL);
73
74 mode = ((fmode & (R_OK|W_OK|X_OK)) << 6);
75
76 cr = CRED();
77
78 /* OK to use effective uid/gid, i.e., no need to crdup(CRED())? */
79 eok = (fmode & E_OK) ||
80 (cr->cr_uid == cr->cr_ruid && cr->cr_gid == cr->cr_rgid);
81
82 if (eok)
83 tmpcr = cr;
84 else {
85 tmpcr = crdup(cr);
86 tmpcr->cr_uid = cr->cr_ruid;
87 tmpcr->cr_gid = cr->cr_rgid;
88 tmpcr->cr_ruid = cr->cr_uid;
89 tmpcr->cr_rgid = cr->cr_gid;
90 }
91
92 lookup:
93 if (error = lookupnameatcred(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp,
94 startvp, tmpcr)) {
95 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++))
96 goto lookup;
97 if (!eok)
98 crfree(tmpcr);
99 return (error);
100 }
101
102 if (mode) {
103 error = VOP_ACCESS(vp, mode, 0, tmpcr, NULL);
104 if (error) {
105 if ((error == ESTALE) &&
106 fs_need_estale_retry(estale_retry++)) {
107 VN_RELE(vp);
108 goto lookup;
109 }
110 }
111 }
112
113 if (!eok)
114 crfree(tmpcr);
115 VN_RELE(vp);
116 return (error);
117 }
118
119 int
faccessat(int fd,char * fname,int fmode,int flag)120 faccessat(int fd, char *fname, int fmode, int flag)
121 {
122 vnode_t *startvp;
123 int error;
124
125 if ((flag & ~AT_EACCESS) != 0)
126 return (set_errno(EINVAL));
127
128 if (fname == NULL)
129 return (set_errno(EFAULT));
130 if ((error = fgetstartvp(fd, fname, &startvp)) != 0)
131 return (set_errno(error));
132 if (AU_AUDITING() && startvp != NULL)
133 audit_setfsat_path(1);
134
135 /* Do not allow E_OK unless AT_EACCESS flag is set */
136 fmode &= ~E_OK;
137 if (flag & AT_EACCESS)
138 fmode |= E_OK;
139
140 error = caccess(fname, fmode, startvp);
141 if (startvp != NULL)
142 VN_RELE(startvp);
143 if (error)
144 return (set_errno(error));
145 return (0);
146 }
147
148 int
access(char * fname,int fmode)149 access(char *fname, int fmode)
150 {
151 return (faccessat(AT_FDCWD, fname, fmode, 0));
152 }
153