-
Notifications
You must be signed in to change notification settings - Fork 1
/
patch-ca.go
295 lines (242 loc) · 8.32 KB
/
patch-ca.go
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
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
/*
MIT License
(C) Copyright 2021-2023 Hewlett Packard Enterprise Development LP
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
*/
package patch
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"crypto/rsa"
"crypto/sha256"
"crypto/x509"
"encoding/base64"
"encoding/binary"
"encoding/json"
"encoding/pem"
"errors"
"github.com/spf13/cobra"
"gopkg.in/yaml.v3"
"io/ioutil"
"log"
)
// SealedSecret - Minimum struct to determine secret scope
// and access encrypted data
type SealedSecret struct {
Spec struct {
EncryptedData map[string]string `yaml:"encryptedData"`
Template struct {
Metadata struct {
Annotations map[string]string
}
}
}
}
// Customizations - Minimum customizations (shasta-cfg) struct
// to access sealed secrets
type Customizations struct {
apiVersion string
Spec struct {
Kubernetes struct {
SealedSecrets map[string]SealedSecret `yaml:"sealed_secrets"`
}
}
}
// CACerts - For storage of ca-certs cloud-init update
type CACerts struct {
RemoveDefaults bool `json:"remove-defaults"`
Trusted []string `json:"trusted"`
}
// Metadata - Boilerplate for cloud-init hierarchical structure
type Metadata struct {
CACerts `json:"ca-certs"`
}
// CloudInitGlobal - Boilerplate for cloud-init hierarchical structure
type CloudInitGlobal struct {
Global struct {
Metadata `json:"meta-data"`
}
}
var customizationsFile string
var sealedSecretsKeyFile string
var sealedSecretName string
var patchCA = &cobra.Command{
Use: "ca",
Short: "Patch cloud-init metadata with CA certs",
Long: `
Patch cloud-init metadata (in place) with certificate authority (CA) certificates from
shasta-cfg (customizations.yaml). Decrypts CA material from named sealed secret using the shasta-cfg
private RSA key.`,
Run: func(cmd *cobra.Command, args []string) {
ciphertext, err := loadEncryptedCABundle(customizationsFile, sealedSecretName, "ca_bundle.crt")
if err != nil {
log.Fatalf("Unable to load CA data from sealed secret, %v \n", err)
}
privKey, err := loadPrivateKey(sealedSecretsKeyFile)
if err != nil {
log.Fatalf("Unable to load sealed secret private key, %v \n", err)
}
plaintext, err := decryptCABundle(privKey, ciphertext)
if err != nil {
log.Fatalf("Unable to decrypt CA bundle, %v \n", err)
}
CABundle, err := formatCABundle(plaintext)
if err != nil {
log.Fatalf("Unable to format CA bundle for cloud-init, %v \n", err)
}
if len(CABundle.Trusted) <= 0 {
log.Fatalf("No CA certificates were found.")
}
var cloudInit CloudInitGlobal
cloudInit.Global.Metadata.CACerts = CABundle
update, err := json.Marshal(cloudInit)
if err != nil {
log.Fatalf("Unable to marshal ca-certs data into JSON, %v \n", err)
}
data, err := backupCloudInitData()
if err != nil {
log.Fatalf("Failed to write backup file, %v \n", err)
}
if err := writeCloudInit(data, update); err != nil {
log.Fatalf("Unable to patch cloud-init seed data in place, %v \n", err)
}
log.Println("Patched cloud-init seed data in place")
},
}
func init() {
PatchCmd.AddCommand(patchCA)
patchCA.DisableAutoGenTag = true
patchCA.Flags().StringVarP(&customizationsFile, "customizations-file", "", "", "path to customizations.yaml (shasta-cfg)")
patchCA.Flags().StringVarP(&sealedSecretsKeyFile, "sealed-secret-key-file", "", "", "Path to sealed secrets/shasta-cfg private key")
patchCA.Flags().StringVarP(&sealedSecretName, "sealed-secret-name", "", "gen_platform_ca_1", "Path to cloud-init metadata seed file")
patchCA.MarkFlagRequired("customizations-file")
patchCA.MarkFlagRequired("sealed-secret-key-file")
}
// Load shasta-cfg customizations, then attempt to return the encrypted CA bundle
// from secretName -> BundleName
func loadEncryptedCABundle(filePath string, secretName string, bundleName string) ([]byte, error) {
customizations, err := ioutil.ReadFile(filePath)
if err != nil {
return nil, err
}
var data Customizations
if err := yaml.Unmarshal(customizations, &data); err != nil {
return nil, err
}
// verify sealed secret scope is cluster-wide
clusterWide, ok := data.Spec.Kubernetes.SealedSecrets[secretName].Spec.Template.Metadata.Annotations["sealedsecrets.bitnami.com/cluster-wide"]
// CMS is currently only using cluster-wide sealed secrets,
// this is important as namespaced secrets include the
// namespace as part of encryption process.
if !ok || clusterWide != "true" {
return nil, errors.New("sealed secret does not have cluster-wide scope, namespaced scope decryption not implemented")
}
b64Bundle, ok := data.Spec.Kubernetes.SealedSecrets[secretName].Spec.EncryptedData[bundleName]
if !ok {
return nil, errors.New("sealed secret or data attribute does not exist")
}
ciphertext, err := base64.StdEncoding.DecodeString(b64Bundle)
if err != nil {
return nil, err
}
return ciphertext, nil
}
// Load and return the sealed secret RSA private key
func loadPrivateKey(filePath string) (*rsa.PrivateKey, error) {
key, err := ioutil.ReadFile(filePath)
if err != nil {
return nil, err
}
KeyPEM, _ := pem.Decode(key)
privKeyParse, err := x509.ParsePKCS8PrivateKey(KeyPEM.Bytes)
if err != nil {
return nil, err
}
privKey := privKeyParse.(*rsa.PrivateKey)
return privKey, nil
}
// Given an encrypted CA bundle from sealed secrets (ciphertext),
// decrypt and return the plaintext
func decryptCABundle(privKey *rsa.PrivateKey, ciphertext []byte) ([]byte, error) {
// Based on https://github.com/bitnami-labs/sealed-secrets/blob/master/pkg/crypto/crypto.go
// The first two bytes contain the length of the encrypted
// AES session key
if len(ciphertext) < 2 {
return nil, errors.New("truncated ciphertext, corrupt data?")
}
// Get the RSA encrypted AES session key length,
// and then right shift the ciphertext
sessionKeyLen := int(binary.BigEndian.Uint16(ciphertext))
ciphertext = ciphertext[2:]
if len(ciphertext) < sessionKeyLen {
return nil, errors.New("ciphertext not long enough to hold session key, corrupt data?")
}
// Get the RSA encrypted AES session key,
// then right shift the ciphertext
sessionKeyEncrypted := ciphertext[:sessionKeyLen]
ciphertext = ciphertext[sessionKeyLen:]
var label []byte // namespace-based scope not implemented, label is empty
rnd := rand.Reader
// Decrypt the AES session key
aesSessionKey, err := rsa.DecryptOAEP(sha256.New(), rnd, privKey, sessionKeyEncrypted, label)
if err != nil {
return nil, err
}
block, err := aes.NewCipher(aesSessionKey)
if err != nil {
return nil, err
}
aed, err := cipher.NewGCM(block)
if err != nil {
return nil, err
}
// Sealed Secrets use a zero Nonce, do the same
zeroNonce := make([]byte, aed.NonceSize())
plaintext, err := aed.Open(nil, zeroNonce, ciphertext, nil)
if err != nil {
return nil, err
}
return plaintext, nil
}
// Given a decrypted PEM bundle, populate and return appropriate
// cloud-init structure
func formatCABundle(raw []byte) (CACerts, error) {
var CABundle CACerts
CABundle.RemoveDefaults = false
// parse each cert from bundle
// convert it to a string, replace
// newlines with \n literals, and add
// to CloudInit data
for {
block, other := pem.Decode(raw)
if block == nil {
break
}
if block.Type == "CERTIFICATE" {
certPem := new(bytes.Buffer)
pem.Encode(certPem, &pem.Block{
Type: "CERTIFICATE",
Bytes: block.Bytes,
})
CABundle.Trusted = append(CABundle.Trusted, certPem.String())
}
raw = other
}
return CABundle, nil
}