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