xref: /freebsd/lib/libc/posix1e/acl_delete_entry.c (revision 3fc36ee018bb836bd1796067cf4ef8683f166ebc)
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 THE 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 #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 *acl_int;
78 	struct acl_entry entry_int;
79 	int i, j, found = 0;
80 
81 	if (acl == NULL || entry_d == NULL) {
82 		errno = EINVAL;
83 		return (-1);
84 	}
85 
86 	acl_int = &acl->ats_acl;
87 
88 	if (_entry_brand(entry_d) != _acl_brand(acl)) {
89 		errno = EINVAL;
90 		return (-1);
91 	}
92 
93 	if ((acl->ats_acl.acl_cnt < 1) ||
94 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
95 		errno = EINVAL;
96 		return (-1);
97 	}
98 
99 	/* Use a local copy to prevent deletion of more than this entry */
100 	entry_int = *entry_d;
101 
102 	for (i = 0; i < acl->ats_acl.acl_cnt;) {
103 		if (_entry_matches(&(acl->ats_acl.acl_entry[i]), &entry_int)) {
104 			/* ...shift the remaining entries... */
105 			for (j = i; j < acl->ats_acl.acl_cnt - 1; ++j)
106 				acl->ats_acl.acl_entry[j] =
107 				    acl->ats_acl.acl_entry[j+1];
108 			/* ...drop the count and zero the unused entry... */
109 			acl->ats_acl.acl_cnt--;
110 			bzero(&acl->ats_acl.acl_entry[j],
111 			    sizeof(struct acl_entry));
112 			acl->ats_cur_entry = 0;
113 
114 			/* Continue with the loop to remove all matching entries. */
115 			found = 1;
116 		} else
117 			i++;
118 	}
119 
120 	if (found)
121 		return (0);
122 
123 	errno = EINVAL;
124 	return (-1);
125 }
126 
127 int
128 acl_delete_entry_np(acl_t acl, int offset)
129 {
130 	struct acl *acl_int;
131 	int i;
132 
133 	if (acl == NULL) {
134 		errno = EINVAL;
135 		return (-1);
136 	}
137 
138 	acl_int = &acl->ats_acl;
139 
140 	if (offset < 0 || offset >= acl_int->acl_cnt) {
141 		errno = EINVAL;
142 		return (-1);
143 	}
144 
145 	if ((acl->ats_acl.acl_cnt < 1) ||
146 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
147 		errno = EINVAL;
148 		return (-1);
149 	}
150 
151 	/* ...shift the remaining entries... */
152 	for (i = offset; i < acl->ats_acl.acl_cnt - 1; ++i)
153 		acl->ats_acl.acl_entry[i] =
154 		    acl->ats_acl.acl_entry[i+1];
155 	/* ...drop the count and zero the unused entry... */
156 	acl->ats_acl.acl_cnt--;
157 	bzero(&acl->ats_acl.acl_entry[i],
158 	    sizeof(struct acl_entry));
159 	acl->ats_cur_entry = 0;
160 
161 	return (0);
162 }
163