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
|
// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2021 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package fde
import (
"bytes"
"encoding/json"
"fmt"
"github.com/snapcore/snapd/osutil"
"github.com/snapcore/snapd/randutil"
)
// RevealKeyRequest carries the operation parameters to the fde-reavel-key
// helper that receives them serialized over stdin.
type RevealKeyRequest struct {
Op string `json:"op"`
SealedKey []byte `json:"sealed-key,omitempty"`
Handle *json.RawMessage `json:"handle,omitempty"`
// deprecated for v1
KeyName string `json:"key-name,omitempty"`
// TODO: add VolumeName,SourceDevicePath later
}
// runFDERevealKeyCommand returns the output of fde-reveal-key run
// with systemd.
//
// Note that systemd-run in the initrd can only talk to the private
// systemd bus so this cannot use "--pipe" or "--wait", see
// https://github.com/snapcore/core-initrd/issues/13
func runFDERevealKeyCommand(req *RevealKeyRequest) (output []byte, err error) {
stdin, err := json.Marshal(req)
if err != nil {
return nil, fmt.Errorf(`cannot build request %v for fde-reveal-key: %v`, req, err)
}
return runFDEinitramfsHelper("fde-reveal-key", stdin)
}
var runFDERevealKey = runFDERevealKeyCommand
func MockRunFDERevealKey(mock func(*RevealKeyRequest) ([]byte, error)) (restore func()) {
osutil.MustBeTestBinary("fde-reveal-key can only be mocked in tests")
oldRunFDERevealKey := runFDERevealKey
runFDERevealKey = mock
return func() {
runFDERevealKey = oldRunFDERevealKey
}
}
func LockSealedKeys() error {
req := &RevealKeyRequest{
Op: "lock",
}
if _, err := runFDERevealKey(req); err != nil {
return err
}
return nil
}
// RevealParams contains the parameters for fde-reveal-key reveal operation.
type RevealParams struct {
SealedKey []byte
Handle *json.RawMessage
// V2Payload is set true if SealedKey is expected to contain a v2 payload
// (disk key + aux key)
V2Payload bool
}
type revealKeyResult struct {
Key []byte `json:"key"`
}
const (
v1keySize = 64
v1NoHandle = `{"v1-no-handle":true}`
)
// Reveal invokes the fde-reveal-key reveal operation.
func Reveal(params *RevealParams) (payload []byte, err error) {
handle := params.Handle
if params.V2Payload && handle != nil && bytes.Equal([]byte(*handle), []byte(v1NoHandle)) {
handle = nil
}
req := &RevealKeyRequest{
Op: "reveal",
SealedKey: params.SealedKey,
Handle: handle,
// deprecated but needed for v1 hooks
KeyName: "deprecated-" + randutil.RandomString(12),
}
output, err := runFDERevealKey(req)
if err != nil {
return nil, err
}
// We expect json output that fits the revealKeyResult json at
// this point. However the "denver" project uses the old and
// deprecated v1 API that returns raw bytes and we still need
// to support this.
var res revealKeyResult
if err := json.Unmarshal(output, &res); err != nil {
if params.V2Payload {
// We expect a v2 payload but not having json
// output from the hook means that either the
// hook is buggy or we have a v1 based hook
// (e.g. "denver" project) with v2 based json
// data on disk. This is supported but we let
// the higher levels unmarshaling of the
// payload deal with the buggy case.
return output, nil
}
// If the payload is not expected to be v2 and, the
// output is not json but matches the size of the
// "denver" project encrypton key (64 bytes) we assume
// we deal with a v1 API.
if len(output) != v1keySize {
return nil, fmt.Errorf(`cannot decode fde-reveal-key "reveal" result: %v`, err)
}
return output, nil
}
return res.Key, nil
}
|
