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
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
package app
import (
"errors"
"os"
"os/exec"
"os/user"
"path"
"strconv"
"git.ophivana.moe/cat/fortify/dbus"
"git.ophivana.moe/cat/fortify/internal"
"git.ophivana.moe/cat/fortify/internal/state"
"git.ophivana.moe/cat/fortify/internal/verbose"
)
const (
LaunchMethodSudo uint8 = iota
LaunchMethodMachineCtl
)
var (
ErrConfig = errors.New("no configuration to seal")
ErrUser = errors.New("unknown user")
ErrLaunch = errors.New("invalid launch method")
ErrSudo = errors.New("sudo not available")
ErrSystemd = errors.New("systemd not available")
ErrMachineCtl = errors.New("machinectl not available")
)
type (
SealConfigError BaseError
LauncherLookupError BaseError
SecurityError BaseError
)
// Seal seals the app launch context
func (a *app) Seal(config *Config) error {
a.lock.Lock()
defer a.lock.Unlock()
if a.seal != nil {
panic("app sealed twice")
}
if config == nil {
return (*SealConfigError)(wrapError(ErrConfig, "attempted to seal app with nil config"))
}
// create seal
seal := new(appSeal)
// generate application ID
if id, err := newAppID(); err != nil {
return (*SecurityError)(wrapError(err, "cannot generate application ID:", err))
} else {
seal.id = id
}
// fetch system constants
seal.SystemConstants = internal.GetSC()
// pass through config values
seal.fid = config.ID
seal.command = config.Command
// parses launch method text and looks up tool path
switch config.Method {
case "sudo":
seal.launchOption = LaunchMethodSudo
if sudoPath, err := exec.LookPath("sudo"); err != nil {
return (*LauncherLookupError)(wrapError(ErrSudo, "sudo not found"))
} else {
seal.toolPath = sudoPath
}
case "systemd":
seal.launchOption = LaunchMethodMachineCtl
if !internal.SdBootedV {
return (*LauncherLookupError)(wrapError(ErrSystemd,
"system has not been booted with systemd as init system"))
}
if machineCtlPath, err := exec.LookPath("machinectl"); err != nil {
return (*LauncherLookupError)(wrapError(ErrMachineCtl, "machinectl not found"))
} else {
seal.toolPath = machineCtlPath
}
default:
return (*SealConfigError)(wrapError(ErrLaunch, "invalid launch method"))
}
// create seal system component
seal.sys = new(appSealTx)
// look up fortify executable path
if p, err := os.Executable(); err != nil {
return (*LauncherLookupError)(wrapError(err, "cannot look up fortify executable path:", err))
} else {
seal.sys.executable = p
}
// look up user from system
if u, err := user.Lookup(config.User); err != nil {
if errors.As(err, new(user.UnknownUserError)) {
return (*SealConfigError)(wrapError(ErrUser, "unknown user", config.User))
} else {
// unreachable
panic(err)
}
} else {
seal.sys.User = u
seal.sys.runtime = path.Join("/run/user", u.Uid)
}
// map sandbox config to bwrap
if config.Confinement.Sandbox == nil {
verbose.Println("sandbox configuration not supplied, PROCEED WITH CAUTION")
// permissive defaults
conf := &SandboxConfig{
UserNS: true,
Net: true,
NoNewSession: true,
}
// bind entries in /
if d, err := os.ReadDir("/"); err != nil {
return err
} else {
b := make([][2]string, 0, len(d))
for _, ent := range d {
name := ent.Name()
switch name {
case "proc":
case "dev":
case "run":
default:
p := "/" + name
b = append(b, [2]string{p, p})
}
}
conf.Bind = append(conf.Bind, b...)
}
// bind entries in /run
if d, err := os.ReadDir("/run"); err != nil {
return err
} else {
b := make([][2]string, 0, len(d))
for _, ent := range d {
name := ent.Name()
switch name {
case "user":
case "dbus":
default:
p := "/run/" + name
b = append(b, [2]string{p, p})
}
}
conf.Bind = append(conf.Bind, b...)
}
config.Confinement.Sandbox = conf
}
seal.sys.bwrap = config.Confinement.Sandbox.Bwrap()
if seal.sys.bwrap.SetEnv == nil {
seal.sys.bwrap.SetEnv = make(map[string]string)
}
// create wayland client wait channel if mediated wayland is enabled
// this channel being set enables mediated wayland setup later on
if config.Confinement.Sandbox.Wayland {
seal.wlDone = make(chan struct{})
}
// open process state store
// the simple store only starts holding an open file after first action
// store activity begins after Start is called and must end before Wait
seal.store = state.NewSimple(seal.SystemConstants.RunDirPath, seal.sys.Uid)
// parse string UID
if u, err := strconv.Atoi(seal.sys.Uid); err != nil {
// unreachable unless kernel bug
panic("uid parse")
} else {
seal.sys.uid = u
}
// pass through enablements
seal.et = config.Confinement.Enablements
// this method calls all share methods in sequence
if err := seal.shareAll([2]*dbus.Config{config.Confinement.SessionBus, config.Confinement.SystemBus}); err != nil {
return err
}
// verbose log seal information
verbose.Println("created application seal as user",
seal.sys.Username, "("+seal.sys.Uid+"),",
"method:", config.Method+",",
"launcher:", seal.toolPath+",",
"command:", config.Command)
// seal app and release lock
a.seal = seal
return nil
}
|
