xref: /freebsd/lib/libc/posix1e/acl_delete_entry.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/types.h>
31 #include "namespace.h"
32 #include <sys/acl.h>
33 #include "un-namespace.h"
34 #include <errno.h>
35 #include <string.h>
36 #include <stdio.h>
37 
38 #include "acl_support.h"
39 
40 static int
41 _entry_matches(const acl_entry_t a, const acl_entry_t b)
42 {
43 	/*
44 	 * There is a semantical difference here between NFSv4 and POSIX
45 	 * draft ACLs.  In POSIX, there may be only one entry for the particular
46 	 * user or group.  In NFSv4 ACL, there may be any number of them.  We're
47 	 * trying to be more specific here in that case.
48 	 */
49 	switch (_entry_brand(a)) {
50 	case ACL_BRAND_NFS4:
51 		if (a->ae_tag != b->ae_tag || a->ae_entry_type != b->ae_entry_type)
52 			return (0);
53 
54 		/* If ae_ids matter, compare them as well. */
55 		if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) {
56 			if (a->ae_id != b->ae_id)
57 				return (0);
58 		}
59 
60 		return (1);
61 
62 	default:
63 		if ((a->ae_tag == b->ae_tag) && (a->ae_id == b->ae_id))
64 			return (1);
65 	}
66 
67 	return (0);
68 }
69 
70 /*
71  * acl_delete_entry() (23.4.9): remove the ACL entry indicated by entry_d
72  * from acl.
73  */
74 int
75 acl_delete_entry(acl_t acl, acl_entry_t entry_d)
76 {
77 	struct acl_entry entry_int;
78 	int i, j, found = 0;
79 
80 	if (acl == NULL || entry_d == NULL) {
81 		errno = EINVAL;
82 		return (-1);
83 	}
84 
85 	if (_entry_brand(entry_d) != _acl_brand(acl)) {
86 		errno = EINVAL;
87 		return (-1);
88 	}
89 
90 	if ((acl->ats_acl.acl_cnt < 1) ||
91 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
92 		errno = EINVAL;
93 		return (-1);
94 	}
95 
96 	/* Use a local copy to prevent deletion of more than this entry */
97 	entry_int = *entry_d;
98 
99 	for (i = 0; i < acl->ats_acl.acl_cnt;) {
100 		if (_entry_matches(&(acl->ats_acl.acl_entry[i]), &entry_int)) {
101 			/* ...shift the remaining entries... */
102 			for (j = i; j < acl->ats_acl.acl_cnt - 1; ++j)
103 				acl->ats_acl.acl_entry[j] =
104 				    acl->ats_acl.acl_entry[j+1];
105 			/* ...drop the count and zero the unused entry... */
106 			acl->ats_acl.acl_cnt--;
107 			bzero(&acl->ats_acl.acl_entry[j],
108 			    sizeof(struct acl_entry));
109 			acl->ats_cur_entry = 0;
110 
111 			/* Continue with the loop to remove all matching entries. */
112 			found = 1;
113 		} else
114 			i++;
115 	}
116 
117 	if (found)
118 		return (0);
119 
120 	errno = EINVAL;
121 	return (-1);
122 }
123 
124 int
125 acl_delete_entry_np(acl_t acl, int offset)
126 {
127 	struct acl *acl_int;
128 	int i;
129 
130 	if (acl == NULL) {
131 		errno = EINVAL;
132 		return (-1);
133 	}
134 
135 	acl_int = &acl->ats_acl;
136 
137 	if (offset < 0 || offset >= acl_int->acl_cnt) {
138 		errno = EINVAL;
139 		return (-1);
140 	}
141 
142 	if ((acl->ats_acl.acl_cnt < 1) ||
143 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
144 		errno = EINVAL;
145 		return (-1);
146 	}
147 
148 	/* ...shift the remaining entries... */
149 	for (i = offset; i < acl->ats_acl.acl_cnt - 1; ++i)
150 		acl->ats_acl.acl_entry[i] =
151 		    acl->ats_acl.acl_entry[i+1];
152 	/* ...drop the count and zero the unused entry... */
153 	acl->ats_acl.acl_cnt--;
154 	bzero(&acl->ats_acl.acl_entry[i],
155 	    sizeof(struct acl_entry));
156 	acl->ats_cur_entry = 0;
157 
158 	return (0);
159 }
160