xref: /freebsd/lib/libc/posix1e/acl_strip.c (revision aa12cea2ccc6e686d6d31cf67d6bc69cbc1ba744)
1 /*-
2  * Copyright (c) 2001 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 <errno.h>
31 #include <stdio.h>
32 #include <assert.h>
33 #include <sys/acl.h>
34 
35 #include "acl_support.h"
36 
37 /*
38  * These two routines from sys/kern/subr_acl_nfs4.c are used by both kernel
39  * and libc.
40  */
41 void	acl_nfs4_sync_acl_from_mode(struct acl *aclp, mode_t mode,
42 	    int file_owner_id);
43 void	acl_nfs4_sync_mode_from_acl(mode_t *_mode, const struct acl *aclp);
44 
45 static acl_t
46 _nfs4_acl_strip_np(const acl_t aclp, int recalculate_mask)
47 {
48 	acl_t newacl;
49 	mode_t mode;
50 
51 	newacl = acl_init(ACL_MAX_ENTRIES);
52 	if (newacl == NULL) {
53 		errno = ENOMEM;
54 		return (NULL);
55 	}
56 
57 	_acl_brand_as(newacl, ACL_BRAND_NFS4);
58 
59 	acl_nfs4_sync_mode_from_acl(&mode, &(aclp->ats_acl));
60 	acl_nfs4_sync_acl_from_mode(&(newacl->ats_acl), mode, -1);
61 
62 	return (newacl);
63 }
64 
65 static acl_t
66 _posix1e_acl_strip_np(const acl_t aclp, int recalculate_mask)
67 {
68 	acl_t acl_new, acl_old;
69 	acl_entry_t entry, entry_new;
70 	acl_permset_t perm;
71 	acl_tag_t tag;
72 	int entry_id, have_mask_entry;
73 
74 	assert(_acl_brand(aclp) == ACL_BRAND_POSIX);
75 
76 	acl_old = acl_dup(aclp);
77 	if (acl_old == NULL)
78 		return (NULL);
79 
80 	assert(_acl_brand(acl_old) == ACL_BRAND_POSIX);
81 
82 	have_mask_entry = 0;
83 	acl_new = acl_init(ACL_MAX_ENTRIES);
84 	if (acl_new == NULL)
85 		return (NULL);
86 	tag = ACL_UNDEFINED_TAG;
87 
88 	/* only save the default user/group/other entries */
89 	entry_id = ACL_FIRST_ENTRY;
90 	while (acl_get_entry(acl_old, entry_id, &entry) == 1) {
91 		entry_id = ACL_NEXT_ENTRY;
92 
93 		assert(_entry_brand(entry) == ACL_BRAND_POSIX);
94 
95 		if (acl_get_tag_type(entry, &tag) == -1)
96 			return (NULL);
97 
98 		switch(tag) {
99 		case ACL_USER_OBJ:
100 		case ACL_GROUP_OBJ:
101 		case ACL_OTHER:
102 			if (acl_get_tag_type(entry, &tag) == -1)
103 				return (NULL);
104 			if (acl_get_permset(entry, &perm) == -1)
105 				return (NULL);
106 			if (acl_create_entry(&acl_new, &entry_new) == -1)
107 				return (NULL);
108 			if (acl_set_tag_type(entry_new, tag) == -1)
109 				return (NULL);
110 			if (acl_set_permset(entry_new, perm) == -1)
111 				return (NULL);
112 			if (acl_copy_entry(entry_new, entry) == -1)
113 				return (NULL);
114 			assert(_entry_brand(entry_new) == ACL_BRAND_POSIX);
115 			break;
116 		case ACL_MASK:
117 			have_mask_entry = 1;
118 			break;
119 		default:
120 			break;
121 		}
122 	}
123 
124 	assert(_acl_brand(acl_new) == ACL_BRAND_POSIX);
125 
126 	if (have_mask_entry && recalculate_mask) {
127 		if (acl_calc_mask(&acl_new) == -1)
128 			return (NULL);
129 	}
130 
131 	return (acl_new);
132 }
133 
134 acl_t
135 acl_strip_np(const acl_t aclp, int recalculate_mask)
136 {
137 	switch (_acl_brand(aclp)) {
138 	case ACL_BRAND_NFS4:
139 		return (_nfs4_acl_strip_np(aclp, recalculate_mask));
140 
141 	case ACL_BRAND_POSIX:
142 		return (_posix1e_acl_strip_np(aclp, recalculate_mask));
143 
144 	default:
145 		errno = EINVAL;
146 		return (NULL);
147 	}
148 }
149 
150 /*
151  * Return 1, if ACL is trivial, 0 otherwise.
152  *
153  * ACL is trivial, iff its meaning could be fully expressed using just file
154  * mode.  In other words, ACL is trivial iff it doesn't have "+" to the right
155  * of the mode bits in "ls -l" output ;-)
156  */
157 int
158 acl_is_trivial_np(const acl_t aclp, int *trivialp)
159 {
160 	acl_t tmpacl;
161 	int differs;
162 
163 	if (aclp == NULL || trivialp == NULL) {
164 		errno = EINVAL;
165 		return (-1);
166 	}
167 
168 	switch (_acl_brand(aclp)) {
169 	case ACL_BRAND_POSIX:
170 		if (aclp->ats_acl.acl_cnt == 3)
171 			*trivialp = 1;
172 		else
173 			*trivialp = 0;
174 
175 		return (0);
176 
177 	case ACL_BRAND_NFS4:
178 		/*
179 		 * Calculate trivial ACL - using acl_strip_np - and compare
180 		 * with the original.
181 		 */
182 		tmpacl = acl_strip_np(aclp, 0);
183 		if (tmpacl == NULL)
184 			return (-1);
185 
186 		differs = _acl_differs(aclp, tmpacl);
187 		acl_free(tmpacl);
188 
189 		if (differs)
190 			*trivialp = 0;
191 		else
192 			*trivialp = 1;
193 
194 		return (0);
195 
196 	default:
197 		errno = EINVAL;
198 		return (-1);
199 	}
200 }
201