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 #if 0
31 __FBSDID("$FreeBSD: head/lib/libc/posix1e/acl_calc_mask.c 326193 2017-11-25 17:12:48Z pfg $");
32 #else
33 __RCSID("$NetBSD: acl_calc_mask.c,v 1.2 2024/01/20 14:52:48 christos Exp $");
34 #endif
35
36 #include "namespace.h"
37
38 #include <sys/types.h>
39 #include <sys/acl.h>
40
41 #include <errno.h>
42 #include <stdio.h>
43
44 #include "acl_support.h"
45
46 /*
47 * acl_calc_mask() (23.4.2): calculate and set the permissions
48 * associated with the ACL_MASK ACL entry. If the ACL already
49 * contains an ACL_MASK entry, its permissions shall be
50 * overwritten; if not, one shall be added.
51 */
52 int
acl_calc_mask(acl_t * acl_p)53 acl_calc_mask(acl_t *acl_p)
54 {
55 struct acl *acl_int, *acl_int_new;
56 acl_t acl_new;
57 size_t i;
58 int mask_mode, mask_num;
59
60 /*
61 * (23.4.2.4) requires acl_p to point to a pointer to a valid ACL.
62 * Since one of the primary reasons to use this function would be
63 * to calculate the appropriate mask to obtain a valid ACL, we only
64 * perform sanity checks here and validate the ACL prior to
65 * returning.
66 */
67 if (acl_p == NULL || *acl_p == NULL) {
68 errno = EINVAL;
69 return (-1);
70 }
71
72 if (!_acl_brand_may_be(*acl_p, ACL_BRAND_POSIX)) {
73 errno = EINVAL;
74 return (-1);
75 }
76 _acl_brand_as(*acl_p, ACL_BRAND_POSIX);
77
78 acl_int = &(*acl_p)->ats_acl;
79 if ((acl_int->acl_cnt < 3) || (acl_int->acl_cnt > ACL_MAX_ENTRIES)) {
80 errno = EINVAL;
81 return (-1);
82 }
83
84 acl_new = acl_dup(*acl_p);
85 if (acl_new == NULL)
86 return (-1);
87 acl_int_new = &acl_new->ats_acl;
88
89 mask_mode = 0;
90 mask_num = -1;
91
92 /* gather permissions and find a mask entry */
93 for (i = 0; i < acl_int_new->acl_cnt; i++) {
94 switch(acl_int_new->acl_entry[i].ae_tag) {
95 case ACL_USER:
96 case ACL_GROUP:
97 case ACL_GROUP_OBJ:
98 mask_mode |=
99 acl_int_new->acl_entry[i].ae_perm & ACL_PERM_BITS;
100 break;
101 case ACL_MASK:
102 mask_num = (int)i;
103 break;
104 }
105 }
106
107 /* if a mask entry already exists, overwrite the perms */
108 if (mask_num != -1)
109 acl_int_new->acl_entry[mask_num].ae_perm = mask_mode;
110 else {
111 /* if no mask exists, check acl_cnt... */
112 if (acl_int_new->acl_cnt == ACL_MAX_ENTRIES) {
113 errno = ENOMEM;
114 acl_free(acl_new);
115 return (-1);
116 }
117 /* ...and add the mask entry */
118 acl_int_new->acl_entry[acl_int_new->acl_cnt].ae_tag = ACL_MASK;
119 acl_int_new->acl_entry[acl_int_new->acl_cnt].ae_id =
120 ACL_UNDEFINED_ID;
121 acl_int_new->acl_entry[acl_int_new->acl_cnt].ae_perm =
122 mask_mode;
123 acl_int_new->acl_cnt++;
124 }
125
126 if (acl_valid(acl_new) == -1) {
127 errno = EINVAL;
128 acl_free(acl_new);
129 return (-1);
130 }
131
132 **acl_p = *acl_new;
133 acl_free(acl_new);
134
135 return (0);
136 }
137