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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
// 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 specutils
import (
"fmt"
"math/bits"
"path"
"slices"
specs "github.com/opencontainers/runtime-spec/specs-go"
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/log"
)
type mapping struct {
set bool
val uint32
}
// optionsMap maps mount propagation-related OCI filesystem options to mount(2)
// syscall flags.
var optionsMap = map[string]mapping{
"acl": {set: true, val: unix.MS_POSIXACL},
"async": {set: false, val: unix.MS_SYNCHRONOUS},
"atime": {set: false, val: unix.MS_NOATIME},
"bind": {set: true, val: unix.MS_BIND},
"defaults": {set: true, val: 0},
"dev": {set: false, val: unix.MS_NODEV},
"diratime": {set: false, val: unix.MS_NODIRATIME},
"dirsync": {set: true, val: unix.MS_DIRSYNC},
"exec": {set: false, val: unix.MS_NOEXEC},
"noexec": {set: true, val: unix.MS_NOEXEC},
"iversion": {set: true, val: unix.MS_I_VERSION},
"loud": {set: false, val: unix.MS_SILENT},
"mand": {set: true, val: unix.MS_MANDLOCK},
"noacl": {set: false, val: unix.MS_POSIXACL},
"noatime": {set: true, val: unix.MS_NOATIME},
"nodev": {set: true, val: unix.MS_NODEV},
"nodiratime": {set: true, val: unix.MS_NODIRATIME},
"noiversion": {set: false, val: unix.MS_I_VERSION},
"nomand": {set: false, val: unix.MS_MANDLOCK},
"norelatime": {set: false, val: unix.MS_RELATIME},
"nostrictatime": {set: false, val: unix.MS_STRICTATIME},
"nosuid": {set: true, val: unix.MS_NOSUID},
"rbind": {set: true, val: unix.MS_BIND | unix.MS_REC},
"relatime": {set: true, val: unix.MS_RELATIME},
"remount": {set: true, val: unix.MS_REMOUNT},
"ro": {set: true, val: unix.MS_RDONLY},
"rw": {set: false, val: unix.MS_RDONLY},
"silent": {set: true, val: unix.MS_SILENT},
"strictatime": {set: true, val: unix.MS_STRICTATIME},
"suid": {set: false, val: unix.MS_NOSUID},
"sync": {set: true, val: unix.MS_SYNCHRONOUS},
}
// propOptionsMap is similar to optionsMap, but it lists propagation options
// that cannot be used together with other flags.
var propOptionsMap = map[string]mapping{
"private": {set: true, val: unix.MS_PRIVATE},
"rprivate": {set: true, val: unix.MS_PRIVATE | unix.MS_REC},
"slave": {set: true, val: unix.MS_SLAVE},
"rslave": {set: true, val: unix.MS_SLAVE | unix.MS_REC},
"unbindable": {set: true, val: unix.MS_UNBINDABLE},
"runbindable": {set: true, val: unix.MS_UNBINDABLE | unix.MS_REC},
}
// invalidOptions list options not allowed.
// - shared: sandbox must be isolated from the host. Propagating mount changes
// from the sandbox to the host breaks the isolation. The sandbox's mount
// table is maintained in sentry memory. Mount operations from the application
// are not propagated to the host.
var invalidOptions = []string{"shared", "rshared"}
// OptionsToFlags converts mount options to syscall flags.
func OptionsToFlags(opts []string) uint32 {
return optionsToFlags(opts, optionsMap)
}
// PropOptionsToFlags converts propagation mount options to syscall flags.
// Propagation options cannot be set other with other options and must be
// handled separately.
func PropOptionsToFlags(opts []string) uint32 {
return optionsToFlags(opts, propOptionsMap)
}
func optionsToFlags(opts []string, source map[string]mapping) uint32 {
var rv uint32
for _, opt := range opts {
if m, ok := source[opt]; ok {
if m.set {
rv |= m.val
} else {
rv ^= m.val
}
}
}
return rv
}
// IsReadonlyMount returns true if the mount options has read only option.
func IsReadonlyMount(opts []string) bool {
for _, o := range opts {
if o == "ro" {
return true
}
}
return false
}
// validateMount validates that spec mounts are correct.
func validateMount(mnt *specs.Mount) error {
if !path.IsAbs(mnt.Destination) {
return fmt.Errorf("Mount.Destination must be an absolute path: %v", mnt)
}
if IsGoferMount(*mnt) {
return ValidateMountOptions(mnt.Options)
}
return nil
}
// FilterMountOptions filters out all invalid mount options.
func FilterMountOptions(opts []string) []string {
out := make([]string, 0, len(opts))
for _, o := range opts {
if err := validateMountOption(o); err == nil {
out = append(out, o)
} else {
log.Warningf("mount option skipped %q: %v", o, err)
}
}
return out
}
// ValidateMountOptions validates that mount options are correct.
func ValidateMountOptions(opts []string) error {
for _, o := range opts {
if err := validateMountOption(o); err != nil {
return err
}
}
return nil
}
func validateMountOption(o string) error {
if slices.Contains(invalidOptions, o) {
return fmt.Errorf("mount option %q is not supported", o)
}
return validatePropagation(o)
}
// ValidateRootfsPropagation validates that rootfs propagation options are
// correct.
func validateRootfsPropagation(opt string) error {
flags := PropOptionsToFlags([]string{opt})
if flags&(unix.MS_SLAVE|unix.MS_PRIVATE) == 0 {
return fmt.Errorf("root mount propagation option must specify private or slave: %q", opt)
}
return validatePropagation(opt)
}
func validatePropagation(opt string) error {
flags := PropOptionsToFlags([]string{opt})
exclusive := flags & (unix.MS_SLAVE | unix.MS_PRIVATE | unix.MS_SHARED | unix.MS_UNBINDABLE)
if bits.OnesCount32(exclusive) > 1 {
return fmt.Errorf("mount propagation options are mutually exclusive: %q", opt)
}
return nil
}
|
