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
|
// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Utilities for testing capabilities on Linux.
#ifndef GVISOR_TEST_UTIL_LINUX_CAPABILITY_UTIL_H_
#define GVISOR_TEST_UTIL_LINUX_CAPABILITY_UTIL_H_
#ifdef __linux__
#include <errno.h>
#include <linux/capability.h>
#include <sys/syscall.h>
#include <unistd.h>
#include "test/util/cleanup.h"
#include "test/util/posix_error.h"
#include "test/util/save_util.h"
#include "test/util/test_util.h"
#ifndef _LINUX_CAPABILITY_VERSION_3
#error Expecting _LINUX_CAPABILITY_VERSION_3 support
#endif
namespace gvisor {
namespace testing {
// HaveCapability returns true if the process has the specified EFFECTIVE
// capability.
inline PosixErrorOr<bool> HaveCapability(int cap) {
if (!cap_valid(cap)) {
return PosixError(EINVAL, "Invalid capability");
}
struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
MaybeSave();
return (caps[CAP_TO_INDEX(cap)].effective & CAP_TO_MASK(cap)) != 0;
}
// SetCapability sets the specified EFFECTIVE capability.
inline PosixError SetCapability(int cap, bool set) {
if (!cap_valid(cap)) {
return PosixError(EINVAL, "Invalid capability");
}
struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
MaybeSave();
if (set) {
caps[CAP_TO_INDEX(cap)].effective |= CAP_TO_MASK(cap);
} else {
caps[CAP_TO_INDEX(cap)].effective &= ~CAP_TO_MASK(cap);
}
header = {_LINUX_CAPABILITY_VERSION_3, 0};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capset, &header, &caps));
MaybeSave();
return NoError();
}
// DropPermittedCapability drops the specified PERMITTED. The EFFECTIVE
// capabilities must be a subset of PERMITTED, so those are dropped as well.
inline PosixError DropPermittedCapability(int cap) {
if (!cap_valid(cap)) {
return PosixError(EINVAL, "Invalid capability");
}
struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
MaybeSave();
caps[CAP_TO_INDEX(cap)].effective &= ~CAP_TO_MASK(cap);
caps[CAP_TO_INDEX(cap)].permitted &= ~CAP_TO_MASK(cap);
header = {_LINUX_CAPABILITY_VERSION_3, 0};
RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capset, &header, &caps));
MaybeSave();
return NoError();
}
PosixErrorOr<bool> CanCreateUserNamespace();
class AutoCapability {
public:
AutoCapability(int cap, bool set) : cap_(cap), set_(set) {
const bool has = EXPECT_NO_ERRNO_AND_VALUE(HaveCapability(cap));
if (set != has) {
EXPECT_NO_ERRNO(SetCapability(cap_, set_));
applied_ = true;
}
}
~AutoCapability() {
if (applied_) {
EXPECT_NO_ERRNO(SetCapability(cap_, !set_));
}
}
private:
int cap_;
bool set_;
bool applied_ = false;
};
} // namespace testing
} // namespace gvisor
#endif // __linux__
#endif // GVISOR_TEST_UTIL_LINUX_CAPABILITY_UTIL_H_
|
