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
|
// 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.
package linux
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/syserror"
)
func lookupCaps(t *kernel.Task, tid kernel.ThreadID) (permitted, inheritable, effective auth.CapabilitySet, err error) {
if tid < 0 {
err = linuxerr.EINVAL
return
}
if tid > 0 {
t = t.PIDNamespace().TaskWithID(tid)
}
if t == nil {
err = syserror.ESRCH
return
}
creds := t.Credentials()
permitted, inheritable, effective = creds.PermittedCaps, creds.InheritableCaps, creds.EffectiveCaps
return
}
// Capget implements Linux syscall capget.
func Capget(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
hdrAddr := args[0].Pointer()
dataAddr := args[1].Pointer()
var hdr linux.CapUserHeader
if _, err := hdr.CopyIn(t, hdrAddr); err != nil {
return 0, nil, err
}
// hdr.Pid doesn't need to be valid if this capget() is a "version probe"
// (hdr.Version is unrecognized and dataAddr is null), so we can't do the
// lookup yet.
switch hdr.Version {
case linux.LINUX_CAPABILITY_VERSION_1:
if dataAddr == 0 {
return 0, nil, nil
}
p, i, e, err := lookupCaps(t, kernel.ThreadID(hdr.Pid))
if err != nil {
return 0, nil, err
}
data := linux.CapUserData{
Effective: uint32(e),
Permitted: uint32(p),
Inheritable: uint32(i),
}
_, err = data.CopyOut(t, dataAddr)
return 0, nil, err
case linux.LINUX_CAPABILITY_VERSION_2, linux.LINUX_CAPABILITY_VERSION_3:
if dataAddr == 0 {
return 0, nil, nil
}
p, i, e, err := lookupCaps(t, kernel.ThreadID(hdr.Pid))
if err != nil {
return 0, nil, err
}
data := [2]linux.CapUserData{
{
Effective: uint32(e),
Permitted: uint32(p),
Inheritable: uint32(i),
},
{
Effective: uint32(e >> 32),
Permitted: uint32(p >> 32),
Inheritable: uint32(i >> 32),
},
}
_, err = linux.CopyCapUserDataSliceOut(t, dataAddr, data[:])
return 0, nil, err
default:
hdr.Version = linux.HighestCapabilityVersion
if _, err := hdr.CopyOut(t, hdrAddr); err != nil {
return 0, nil, err
}
if dataAddr != 0 {
return 0, nil, linuxerr.EINVAL
}
return 0, nil, nil
}
}
// Capset implements Linux syscall capset.
func Capset(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
hdrAddr := args[0].Pointer()
dataAddr := args[1].Pointer()
var hdr linux.CapUserHeader
if _, err := hdr.CopyIn(t, hdrAddr); err != nil {
return 0, nil, err
}
switch hdr.Version {
case linux.LINUX_CAPABILITY_VERSION_1:
if tid := kernel.ThreadID(hdr.Pid); tid != 0 && tid != t.ThreadID() {
return 0, nil, syserror.EPERM
}
var data linux.CapUserData
if _, err := data.CopyIn(t, dataAddr); err != nil {
return 0, nil, err
}
p := auth.CapabilitySet(data.Permitted) & auth.AllCapabilities
i := auth.CapabilitySet(data.Inheritable) & auth.AllCapabilities
e := auth.CapabilitySet(data.Effective) & auth.AllCapabilities
return 0, nil, t.SetCapabilitySets(p, i, e)
case linux.LINUX_CAPABILITY_VERSION_2, linux.LINUX_CAPABILITY_VERSION_3:
if tid := kernel.ThreadID(hdr.Pid); tid != 0 && tid != t.ThreadID() {
return 0, nil, syserror.EPERM
}
var data [2]linux.CapUserData
if _, err := linux.CopyCapUserDataSliceIn(t, dataAddr, data[:]); err != nil {
return 0, nil, err
}
p := (auth.CapabilitySet(data[0].Permitted) | (auth.CapabilitySet(data[1].Permitted) << 32)) & auth.AllCapabilities
i := (auth.CapabilitySet(data[0].Inheritable) | (auth.CapabilitySet(data[1].Inheritable) << 32)) & auth.AllCapabilities
e := (auth.CapabilitySet(data[0].Effective) | (auth.CapabilitySet(data[1].Effective) << 32)) & auth.AllCapabilities
return 0, nil, t.SetCapabilitySets(p, i, e)
default:
hdr.Version = linux.HighestCapabilityVersion
if _, err := hdr.CopyOut(t, hdrAddr); err != nil {
return 0, nil, err
}
return 0, nil, linuxerr.EINVAL
}
}
|
