1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2001-2002 Chris D. Faulhaber
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: stable/12/lib/libc/posix1e/acl_calc_mask.c 326193 2017-11-25 17:12:48Z pfg $");
31
32 #include <sys/types.h>
33 #include "namespace.h"
34 #include <sys/acl.h>
35 #include "un-namespace.h"
36
37 #include <errno.h>
38 #include <stdio.h>
39
40 #include "acl_support.h"
41
42 /*
43 * acl_calc_mask() (23.4.2): calculate and set the permissions
44 * associated with the ACL_MASK ACL entry. If the ACL already
45 * contains an ACL_MASK entry, its permissions shall be
46 * overwritten; if not, one shall be added.
47 */
48 int
acl_calc_mask(acl_t * acl_p)49 acl_calc_mask(acl_t *acl_p)
50 {
51 struct acl *acl_int, *acl_int_new;
52 acl_t acl_new;
53 int i, mask_mode, mask_num;
54
55 /*
56 * (23.4.2.4) requires acl_p to point to a pointer to a valid ACL.
57 * Since one of the primary reasons to use this function would be
58 * to calculate the appropriate mask to obtain a valid ACL, we only
59 * perform sanity checks here and validate the ACL prior to
60 * returning.
61 */
62 if (acl_p == NULL || *acl_p == NULL) {
63 errno = EINVAL;
64 return (-1);
65 }
66
67 if (!_acl_brand_may_be(*acl_p, ACL_BRAND_POSIX)) {
68 errno = EINVAL;
69 return (-1);
70 }
71 _acl_brand_as(*acl_p, ACL_BRAND_POSIX);
72
73 acl_int = &(*acl_p)->ats_acl;
74 if ((acl_int->acl_cnt < 3) || (acl_int->acl_cnt > ACL_MAX_ENTRIES)) {
75 errno = EINVAL;
76 return (-1);
77 }
78
79 acl_new = acl_dup(*acl_p);
80 if (acl_new == NULL)
81 return (-1);
82 acl_int_new = &acl_new->ats_acl;
83
84 mask_mode = 0;
85 mask_num = -1;
86
87 /* gather permissions and find a mask entry */
88 for (i = 0; i < acl_int_new->acl_cnt; i++) {
89 switch(acl_int_new->acl_entry[i].ae_tag) {
90 case ACL_USER:
91 case ACL_GROUP:
92 case ACL_GROUP_OBJ:
93 mask_mode |=
94 acl_int_new->acl_entry[i].ae_perm & ACL_PERM_BITS;
95 break;
96 case ACL_MASK:
97 mask_num = i;
98 break;
99 }
100 }
101
102 /* if a mask entry already exists, overwrite the perms */
103 if (mask_num != -1)
104 acl_int_new->acl_entry[mask_num].ae_perm = mask_mode;
105 else {
106 /* if no mask exists, check acl_cnt... */
107 if (acl_int_new->acl_cnt == ACL_MAX_ENTRIES) {
108 errno = ENOMEM;
109 acl_free(acl_new);
110 return (-1);
111 }
112 /* ...and add the mask entry */
113 acl_int_new->acl_entry[acl_int_new->acl_cnt].ae_tag = ACL_MASK;
114 acl_int_new->acl_entry[acl_int_new->acl_cnt].ae_id =
115 ACL_UNDEFINED_ID;
116 acl_int_new->acl_entry[acl_int_new->acl_cnt].ae_perm =
117 mask_mode;
118 acl_int_new->acl_cnt++;
119 }
120
121 if (acl_valid(acl_new) == -1) {
122 errno = EINVAL;
123 acl_free(acl_new);
124 return (-1);
125 }
126
127 **acl_p = *acl_new;
128 acl_free(acl_new);
129
130 return (0);
131 }
132