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
|
/*
* Copyright 2026, Vincent Douillet <vincent@vdouillet.fr>
*
* 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.
*
* 3. Neither the name of the copyright holder nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* 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 HOLDER 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.
*/
#include <linux/landlock.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <fcntl.h>
#include <stddef.h>
#include "vll_sandbox.h"
/*
* TODO add missing accesses to deny them by default.
* Also move inside vll_create_ruleset
*/
static struct landlock_ruleset_attr ruleset_attr = {
.handled_access_fs =
LANDLOCK_ACCESS_FS_WRITE_FILE |
LANDLOCK_ACCESS_FS_READ_FILE |
LANDLOCK_ACCESS_FS_READ_DIR |
LANDLOCK_ACCESS_FS_REMOVE_DIR |
LANDLOCK_ACCESS_FS_REMOVE_FILE |
LANDLOCK_ACCESS_FS_MAKE_DIR |
LANDLOCK_ACCESS_FS_MAKE_REG,
};
int
vll_create_ruleset()
{
int abi;
abi = syscall(SYS_landlock_create_ruleset, NULL, 0,
LANDLOCK_CREATE_RULESET_VERSION);
if (abi < 0)
return -1;
return syscall(SYS_landlock_create_ruleset, &ruleset_attr,
sizeof(ruleset_attr), 0);
}
int
vll_add_rule(int ruleset_fd, const char *path, const char perm)
{
int err;
struct landlock_path_beneath_attr path_beneath;
path_beneath.allowed_access = 0;
if (perm & VLL_READ)
path_beneath.allowed_access |= LANDLOCK_ACCESS_FS_READ_FILE |
LANDLOCK_ACCESS_FS_READ_DIR;
if (perm & VLL_WRITE)
path_beneath.allowed_access |= LANDLOCK_ACCESS_FS_WRITE_FILE |
LANDLOCK_ACCESS_FS_REMOVE_DIR | LANDLOCK_ACCESS_FS_REMOVE_FILE |
LANDLOCK_ACCESS_FS_MAKE_DIR | LANDLOCK_ACCESS_FS_MAKE_REG;
if (!path_beneath.allowed_access)
return -1;
path_beneath.parent_fd = open(path, O_CLOEXEC);
if (path_beneath.parent_fd < 0)
return -1;
err = syscall(SYS_landlock_add_rule, ruleset_fd,
LANDLOCK_RULE_PATH_BENEATH, &path_beneath, 0);
close(path_beneath.parent_fd);
if (err)
return -1;
return 0;
}
int
vll_restrict_self(int ruleset_fd)
{
int ret;
ret = 0;
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
ret = -1;
goto end;
}
if (syscall(SYS_landlock_restrict_self, ruleset_fd, 0)) {
ret = -1;
goto end;
}
end:
close(ruleset_fd);
return ret;
}
|
