xref: /freebsd/lib/libc/posix1e/acl_delete_entry.c (revision f5463265955b829775bbb32e1fd0bc11dafc36ce)
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/types.h>
30 #include "namespace.h"
31 #include <sys/acl.h>
32 #include "un-namespace.h"
33 #include <errno.h>
34 #include <string.h>
35 #include <stdio.h>
36 
37 #include "acl_support.h"
38 
39 static int
40 _entry_matches(const acl_entry_t a, const acl_entry_t b)
41 {
42 	/*
43 	 * There is a semantical difference here between NFSv4 and POSIX
44 	 * draft ACLs.  In POSIX, there may be only one entry for the particular
45 	 * user or group.  In NFSv4 ACL, there may be any number of them.  We're
46 	 * trying to be more specific here in that case.
47 	 */
48 	switch (_entry_brand(a)) {
49 	case ACL_BRAND_NFS4:
50 		if (a->ae_tag != b->ae_tag || a->ae_entry_type != b->ae_entry_type)
51 			return (0);
52 
53 		/* If ae_ids matter, compare them as well. */
54 		if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) {
55 			if (a->ae_id != b->ae_id)
56 				return (0);
57 		}
58 
59 		return (1);
60 
61 	default:
62 		if ((a->ae_tag == b->ae_tag) && (a->ae_id == b->ae_id))
63 			return (1);
64 	}
65 
66 	return (0);
67 }
68 
69 /*
70  * acl_delete_entry() (23.4.9): remove the ACL entry indicated by entry_d
71  * from acl.
72  */
73 int
74 acl_delete_entry(acl_t acl, acl_entry_t entry_d)
75 {
76 	struct acl_entry entry_int;
77 	int i, j, found = 0;
78 
79 	if (acl == NULL || entry_d == NULL) {
80 		errno = EINVAL;
81 		return (-1);
82 	}
83 
84 	if (_entry_brand(entry_d) != _acl_brand(acl)) {
85 		errno = EINVAL;
86 		return (-1);
87 	}
88 
89 	if ((acl->ats_acl.acl_cnt < 1) ||
90 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
91 		errno = EINVAL;
92 		return (-1);
93 	}
94 
95 	/* Use a local copy to prevent deletion of more than this entry */
96 	entry_int = *entry_d;
97 
98 	for (i = 0; i < acl->ats_acl.acl_cnt;) {
99 		if (_entry_matches(&(acl->ats_acl.acl_entry[i]), &entry_int)) {
100 			/* ...shift the remaining entries... */
101 			for (j = i; j < acl->ats_acl.acl_cnt - 1; ++j)
102 				acl->ats_acl.acl_entry[j] =
103 				    acl->ats_acl.acl_entry[j+1];
104 			/* ...drop the count and zero the unused entry... */
105 			acl->ats_acl.acl_cnt--;
106 			bzero(&acl->ats_acl.acl_entry[j],
107 			    sizeof(struct acl_entry));
108 			acl->ats_cur_entry = 0;
109 
110 			/* Continue with the loop to remove all matching entries. */
111 			found = 1;
112 		} else
113 			i++;
114 	}
115 
116 	if (found)
117 		return (0);
118 
119 	errno = EINVAL;
120 	return (-1);
121 }
122 
123 int
124 acl_delete_entry_np(acl_t acl, int offset)
125 {
126 	struct acl *acl_int;
127 	int i;
128 
129 	if (acl == NULL) {
130 		errno = EINVAL;
131 		return (-1);
132 	}
133 
134 	acl_int = &acl->ats_acl;
135 
136 	if (offset < 0 || offset >= acl_int->acl_cnt) {
137 		errno = EINVAL;
138 		return (-1);
139 	}
140 
141 	if ((acl->ats_acl.acl_cnt < 1) ||
142 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
143 		errno = EINVAL;
144 		return (-1);
145 	}
146 
147 	/* ...shift the remaining entries... */
148 	for (i = offset; i < acl->ats_acl.acl_cnt - 1; ++i)
149 		acl->ats_acl.acl_entry[i] =
150 		    acl->ats_acl.acl_entry[i+1];
151 	/* ...drop the count and zero the unused entry... */
152 	acl->ats_acl.acl_cnt--;
153 	bzero(&acl->ats_acl.acl_entry[i],
154 	    sizeof(struct acl_entry));
155 	acl->ats_cur_entry = 0;
156 
157 	return (0);
158 }
159