1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @brief RTEMS File System Permissions Check Support
* @ingroup LibIOInternal
*/
/*
* Copyright (c) 2012 embedded brains GmbH & Co. KG
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/stat.h>
#include <rtems/libio_.h>
#define RTEMS_FS_USR_SHIFT 6
#define RTEMS_FS_GRP_SHIFT 3
#define RTEMS_FS_OTH_SHIFT 0
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_READ << RTEMS_FS_USR_SHIFT) == S_IRUSR,
S_IRUSR
);
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_READ << RTEMS_FS_GRP_SHIFT) == S_IRGRP,
S_IRGRP
);
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_READ << RTEMS_FS_OTH_SHIFT) == S_IROTH,
S_IROTH
);
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_WRITE << RTEMS_FS_USR_SHIFT) == S_IWUSR,
S_IWUSR
);
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_WRITE << RTEMS_FS_GRP_SHIFT) == S_IWGRP,
S_IWGRP
);
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_WRITE << RTEMS_FS_OTH_SHIFT) == S_IWOTH,
S_IWOTH
);
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_EXEC << RTEMS_FS_USR_SHIFT) == S_IXUSR,
S_IXUSR
);
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_EXEC << RTEMS_FS_GRP_SHIFT) == S_IXGRP,
S_IXGRP
);
RTEMS_STATIC_ASSERT(
(RTEMS_FS_PERMS_EXEC << RTEMS_FS_OTH_SHIFT) == S_IXOTH,
S_IXOTH
);
static bool equals_supplementary_group(
const rtems_user_env_t *uenv,
gid_t object_gid
)
{
size_t i;
for (i = 0; i < uenv->ngroups; ++i) {
if (uenv->groups[i] == object_gid) {
return true;
}
}
return false;
}
bool rtems_filesystem_check_access(
int flags,
mode_t object_mode,
uid_t object_uid,
gid_t object_gid
)
{
const rtems_user_env_t *uenv = rtems_current_user_env_get();
mode_t access_flags = flags & RTEMS_FS_PERMS_RWX;
uid_t task_uid = uenv->euid;
if (task_uid == 0 || task_uid == object_uid) {
access_flags <<= RTEMS_FS_USR_SHIFT;
} else {
gid_t task_gid = uenv->egid;
if (
task_gid == 0
|| task_gid == object_gid
|| equals_supplementary_group(uenv, object_gid)
) {
access_flags <<= RTEMS_FS_GRP_SHIFT;
} else {
access_flags <<= RTEMS_FS_OTH_SHIFT;
}
}
return (access_flags & object_mode) == access_flags;
}
bool rtems_filesystem_eval_path_check_access(
rtems_filesystem_eval_path_context_t *ctx,
int eval_flags,
mode_t node_mode,
uid_t node_uid,
gid_t node_gid
)
{
bool access_ok = rtems_filesystem_check_access(
eval_flags,
node_mode,
node_uid,
node_gid
);
if (!access_ok) {
rtems_filesystem_eval_path_error(ctx, EACCES);
}
return access_ok;
}
|
