File: jwe.go

package info (click to toggle)
golang-gopkg-square-go-jose.v2 2.5.1-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, experimental, sid
  • size: 1,004 kB
  • sloc: makefile: 4
file content (294 lines) | stat: -rw-r--r-- 8,784 bytes parent folder | download | duplicates (3)
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
/*-
 * Copyright 2014 Square Inc.
 *
 * 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 jose

import (
	"encoding/base64"
	"fmt"
	"strings"

	"gopkg.in/square/go-jose.v2/json"
)

// rawJSONWebEncryption represents a raw JWE JSON object. Used for parsing/serializing.
type rawJSONWebEncryption struct {
	Protected    *byteBuffer        `json:"protected,omitempty"`
	Unprotected  *rawHeader         `json:"unprotected,omitempty"`
	Header       *rawHeader         `json:"header,omitempty"`
	Recipients   []rawRecipientInfo `json:"recipients,omitempty"`
	Aad          *byteBuffer        `json:"aad,omitempty"`
	EncryptedKey *byteBuffer        `json:"encrypted_key,omitempty"`
	Iv           *byteBuffer        `json:"iv,omitempty"`
	Ciphertext   *byteBuffer        `json:"ciphertext,omitempty"`
	Tag          *byteBuffer        `json:"tag,omitempty"`
}

// rawRecipientInfo represents a raw JWE Per-Recipient header JSON object. Used for parsing/serializing.
type rawRecipientInfo struct {
	Header       *rawHeader `json:"header,omitempty"`
	EncryptedKey string     `json:"encrypted_key,omitempty"`
}

// JSONWebEncryption represents an encrypted JWE object after parsing.
type JSONWebEncryption struct {
	Header                   Header
	protected, unprotected   *rawHeader
	recipients               []recipientInfo
	aad, iv, ciphertext, tag []byte
	original                 *rawJSONWebEncryption
}

// recipientInfo represents a raw JWE Per-Recipient header JSON object after parsing.
type recipientInfo struct {
	header       *rawHeader
	encryptedKey []byte
}

// GetAuthData retrieves the (optional) authenticated data attached to the object.
func (obj JSONWebEncryption) GetAuthData() []byte {
	if obj.aad != nil {
		out := make([]byte, len(obj.aad))
		copy(out, obj.aad)
		return out
	}

	return nil
}

// Get the merged header values
func (obj JSONWebEncryption) mergedHeaders(recipient *recipientInfo) rawHeader {
	out := rawHeader{}
	out.merge(obj.protected)
	out.merge(obj.unprotected)

	if recipient != nil {
		out.merge(recipient.header)
	}

	return out
}

// Get the additional authenticated data from a JWE object.
func (obj JSONWebEncryption) computeAuthData() []byte {
	var protected string

	if obj.original != nil && obj.original.Protected != nil {
		protected = obj.original.Protected.base64()
	} else if obj.protected != nil {
		protected = base64.RawURLEncoding.EncodeToString(mustSerializeJSON((obj.protected)))
	} else {
		protected = ""
	}

	output := []byte(protected)
	if obj.aad != nil {
		output = append(output, '.')
		output = append(output, []byte(base64.RawURLEncoding.EncodeToString(obj.aad))...)
	}

	return output
}

// ParseEncrypted parses an encrypted message in compact or full serialization format.
func ParseEncrypted(input string) (*JSONWebEncryption, error) {
	input = stripWhitespace(input)
	if strings.HasPrefix(input, "{") {
		return parseEncryptedFull(input)
	}

	return parseEncryptedCompact(input)
}

// parseEncryptedFull parses a message in compact format.
func parseEncryptedFull(input string) (*JSONWebEncryption, error) {
	var parsed rawJSONWebEncryption
	err := json.Unmarshal([]byte(input), &parsed)
	if err != nil {
		return nil, err
	}

	return parsed.sanitized()
}

// sanitized produces a cleaned-up JWE object from the raw JSON.
func (parsed *rawJSONWebEncryption) sanitized() (*JSONWebEncryption, error) {
	obj := &JSONWebEncryption{
		original:    parsed,
		unprotected: parsed.Unprotected,
	}

	// Check that there is not a nonce in the unprotected headers
	if parsed.Unprotected != nil {
		if nonce := parsed.Unprotected.getNonce(); nonce != "" {
			return nil, ErrUnprotectedNonce
		}
	}
	if parsed.Header != nil {
		if nonce := parsed.Header.getNonce(); nonce != "" {
			return nil, ErrUnprotectedNonce
		}
	}

	if parsed.Protected != nil && len(parsed.Protected.bytes()) > 0 {
		err := json.Unmarshal(parsed.Protected.bytes(), &obj.protected)
		if err != nil {
			return nil, fmt.Errorf("square/go-jose: invalid protected header: %s, %s", err, parsed.Protected.base64())
		}
	}

	// Note: this must be called _after_ we parse the protected header,
	// otherwise fields from the protected header will not get picked up.
	var err error
	mergedHeaders := obj.mergedHeaders(nil)
	obj.Header, err = mergedHeaders.sanitized()
	if err != nil {
		return nil, fmt.Errorf("square/go-jose: cannot sanitize merged headers: %v (%v)", err, mergedHeaders)
	}

	if len(parsed.Recipients) == 0 {
		obj.recipients = []recipientInfo{
			{
				header:       parsed.Header,
				encryptedKey: parsed.EncryptedKey.bytes(),
			},
		}
	} else {
		obj.recipients = make([]recipientInfo, len(parsed.Recipients))
		for r := range parsed.Recipients {
			encryptedKey, err := base64.RawURLEncoding.DecodeString(parsed.Recipients[r].EncryptedKey)
			if err != nil {
				return nil, err
			}

			// Check that there is not a nonce in the unprotected header
			if parsed.Recipients[r].Header != nil && parsed.Recipients[r].Header.getNonce() != "" {
				return nil, ErrUnprotectedNonce
			}

			obj.recipients[r].header = parsed.Recipients[r].Header
			obj.recipients[r].encryptedKey = encryptedKey
		}
	}

	for _, recipient := range obj.recipients {
		headers := obj.mergedHeaders(&recipient)
		if headers.getAlgorithm() == "" || headers.getEncryption() == "" {
			return nil, fmt.Errorf("square/go-jose: message is missing alg/enc headers")
		}
	}

	obj.iv = parsed.Iv.bytes()
	obj.ciphertext = parsed.Ciphertext.bytes()
	obj.tag = parsed.Tag.bytes()
	obj.aad = parsed.Aad.bytes()

	return obj, nil
}

// parseEncryptedCompact parses a message in compact format.
func parseEncryptedCompact(input string) (*JSONWebEncryption, error) {
	parts := strings.Split(input, ".")
	if len(parts) != 5 {
		return nil, fmt.Errorf("square/go-jose: compact JWE format must have five parts")
	}

	rawProtected, err := base64.RawURLEncoding.DecodeString(parts[0])
	if err != nil {
		return nil, err
	}

	encryptedKey, err := base64.RawURLEncoding.DecodeString(parts[1])
	if err != nil {
		return nil, err
	}

	iv, err := base64.RawURLEncoding.DecodeString(parts[2])
	if err != nil {
		return nil, err
	}

	ciphertext, err := base64.RawURLEncoding.DecodeString(parts[3])
	if err != nil {
		return nil, err
	}

	tag, err := base64.RawURLEncoding.DecodeString(parts[4])
	if err != nil {
		return nil, err
	}

	raw := &rawJSONWebEncryption{
		Protected:    newBuffer(rawProtected),
		EncryptedKey: newBuffer(encryptedKey),
		Iv:           newBuffer(iv),
		Ciphertext:   newBuffer(ciphertext),
		Tag:          newBuffer(tag),
	}

	return raw.sanitized()
}

// CompactSerialize serializes an object using the compact serialization format.
func (obj JSONWebEncryption) CompactSerialize() (string, error) {
	if len(obj.recipients) != 1 || obj.unprotected != nil ||
		obj.protected == nil || obj.recipients[0].header != nil {
		return "", ErrNotSupported
	}

	serializedProtected := mustSerializeJSON(obj.protected)

	return fmt.Sprintf(
		"%s.%s.%s.%s.%s",
		base64.RawURLEncoding.EncodeToString(serializedProtected),
		base64.RawURLEncoding.EncodeToString(obj.recipients[0].encryptedKey),
		base64.RawURLEncoding.EncodeToString(obj.iv),
		base64.RawURLEncoding.EncodeToString(obj.ciphertext),
		base64.RawURLEncoding.EncodeToString(obj.tag)), nil
}

// FullSerialize serializes an object using the full JSON serialization format.
func (obj JSONWebEncryption) FullSerialize() string {
	raw := rawJSONWebEncryption{
		Unprotected:  obj.unprotected,
		Iv:           newBuffer(obj.iv),
		Ciphertext:   newBuffer(obj.ciphertext),
		EncryptedKey: newBuffer(obj.recipients[0].encryptedKey),
		Tag:          newBuffer(obj.tag),
		Aad:          newBuffer(obj.aad),
		Recipients:   []rawRecipientInfo{},
	}

	if len(obj.recipients) > 1 {
		for _, recipient := range obj.recipients {
			info := rawRecipientInfo{
				Header:       recipient.header,
				EncryptedKey: base64.RawURLEncoding.EncodeToString(recipient.encryptedKey),
			}
			raw.Recipients = append(raw.Recipients, info)
		}
	} else {
		// Use flattened serialization
		raw.Header = obj.recipients[0].header
		raw.EncryptedKey = newBuffer(obj.recipients[0].encryptedKey)
	}

	if obj.protected != nil {
		raw.Protected = newBuffer(mustSerializeJSON(obj.protected))
	}

	return string(mustSerializeJSON(raw))
}