xref: /freebsd/lib/libc/posix1e/acl_delete_entry.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 THE 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 #include <errno.h>
37 #include <string.h>
38 #include <stdio.h>
39 
40 #include "acl_support.h"
41 
42 static int
43 _entry_matches(const acl_entry_t a, const acl_entry_t b)
44 {
45 	/*
46 	 * There is a semantical difference here between NFSv4 and POSIX
47 	 * draft ACLs.  In POSIX, there may be only one entry for the particular
48 	 * user or group.  In NFSv4 ACL, there may be any number of them.  We're
49 	 * trying to be more specific here in that case.
50 	 */
51 	switch (_entry_brand(a)) {
52 	case ACL_BRAND_NFS4:
53 		if (a->ae_tag != b->ae_tag || a->ae_entry_type != b->ae_entry_type)
54 			return (0);
55 
56 		/* If ae_ids matter, compare them as well. */
57 		if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) {
58 			if (a->ae_id != b->ae_id)
59 				return (0);
60 		}
61 
62 		return (1);
63 
64 	default:
65 		if ((a->ae_tag == b->ae_tag) && (a->ae_id == b->ae_id))
66 			return (1);
67 	}
68 
69 	return (0);
70 }
71 
72 /*
73  * acl_delete_entry() (23.4.9): remove the ACL entry indicated by entry_d
74  * from acl.
75  */
76 int
77 acl_delete_entry(acl_t acl, acl_entry_t entry_d)
78 {
79 	struct acl *acl_int;
80 	struct acl_entry entry_int;
81 	int i, j, found = 0;
82 
83 	if (acl == NULL || entry_d == NULL) {
84 		errno = EINVAL;
85 		return (-1);
86 	}
87 
88 	acl_int = &acl->ats_acl;
89 
90 	if (_entry_brand(entry_d) != _acl_brand(acl)) {
91 		errno = EINVAL;
92 		return (-1);
93 	}
94 
95 	if ((acl->ats_acl.acl_cnt < 1) ||
96 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
97 		errno = EINVAL;
98 		return (-1);
99 	}
100 
101 	/* Use a local copy to prevent deletion of more than this entry */
102 	entry_int = *entry_d;
103 
104 	for (i = 0; i < acl->ats_acl.acl_cnt;) {
105 		if (_entry_matches(&(acl->ats_acl.acl_entry[i]), &entry_int)) {
106 			/* ...shift the remaining entries... */
107 			for (j = i; j < acl->ats_acl.acl_cnt - 1; ++j)
108 				acl->ats_acl.acl_entry[j] =
109 				    acl->ats_acl.acl_entry[j+1];
110 			/* ...drop the count and zero the unused entry... */
111 			acl->ats_acl.acl_cnt--;
112 			bzero(&acl->ats_acl.acl_entry[j],
113 			    sizeof(struct acl_entry));
114 			acl->ats_cur_entry = 0;
115 
116 			/* Continue with the loop to remove all matching entries. */
117 			found = 1;
118 		} else
119 			i++;
120 	}
121 
122 	if (found)
123 		return (0);
124 
125 	errno = EINVAL;
126 	return (-1);
127 }
128 
129 int
130 acl_delete_entry_np(acl_t acl, int offset)
131 {
132 	struct acl *acl_int;
133 	int i;
134 
135 	if (acl == NULL) {
136 		errno = EINVAL;
137 		return (-1);
138 	}
139 
140 	acl_int = &acl->ats_acl;
141 
142 	if (offset < 0 || offset >= acl_int->acl_cnt) {
143 		errno = EINVAL;
144 		return (-1);
145 	}
146 
147 	if ((acl->ats_acl.acl_cnt < 1) ||
148 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
149 		errno = EINVAL;
150 		return (-1);
151 	}
152 
153 	/* ...shift the remaining entries... */
154 	for (i = offset; i < acl->ats_acl.acl_cnt - 1; ++i)
155 		acl->ats_acl.acl_entry[i] =
156 		    acl->ats_acl.acl_entry[i+1];
157 	/* ...drop the count and zero the unused entry... */
158 	acl->ats_acl.acl_cnt--;
159 	bzero(&acl->ats_acl.acl_entry[i],
160 	    sizeof(struct acl_entry));
161 	acl->ats_cur_entry = 0;
162 
163 	return (0);
164 }
165