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("$FreeBSD$");
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 */
48int
49acl_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