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1// Copyright 2010 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package runner
6
7import (
8	"crypto"
9	"crypto/aes"
10	"crypto/cipher"
11	"crypto/des"
12	"crypto/hmac"
13	"crypto/md5"
14	"crypto/sha1"
15	"crypto/sha256"
16	"crypto/sha512"
17	"crypto/x509"
18	"hash"
19)
20
21// a keyAgreement implements the client and server side of a TLS key agreement
22// protocol by generating and processing key exchange messages.
23type keyAgreement interface {
24	// On the server side, the first two methods are called in order.
25
26	// In the case that the key agreement protocol doesn't use a
27	// ServerKeyExchange message, generateServerKeyExchange can return nil,
28	// nil.
29	generateServerKeyExchange(*Config, *Certificate, *clientHelloMsg, *serverHelloMsg, uint16) (*serverKeyExchangeMsg, error)
30	processClientKeyExchange(*Config, *Certificate, *clientKeyExchangeMsg, uint16) ([]byte, error)
31
32	// On the client side, the next two methods are called in order.
33
34	// This method may not be called if the server doesn't send a
35	// ServerKeyExchange message.
36	processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, crypto.PublicKey, *serverKeyExchangeMsg) error
37	generateClientKeyExchange(*Config, *clientHelloMsg, *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error)
38
39	// peerSignatureAlgorithm returns the signature algorithm used by the
40	// peer, or zero if not applicable.
41	peerSignatureAlgorithm() signatureAlgorithm
42}
43
44const (
45	// suiteECDH indicates that the cipher suite involves elliptic curve
46	// Diffie-Hellman. This means that it should only be selected when the
47	// client indicates that it supports ECC with a curve and point format
48	// that we're happy with.
49	suiteECDHE = 1 << iota
50	// suiteECDSA indicates that the cipher suite involves an ECDSA
51	// signature and therefore may only be selected when the server's
52	// certificate is ECDSA. If this is not set then the cipher suite is
53	// RSA based.
54	suiteECDSA
55	// suiteTLS12 indicates that the cipher suite should only be advertised
56	// and accepted when using TLS 1.2 or greater.
57	suiteTLS12
58	// suiteTLS13 indicates that the cipher suite can be used with TLS 1.3.
59	// Cipher suites lacking this flag may not be used with TLS 1.3.
60	suiteTLS13
61	// suiteSHA384 indicates that the cipher suite uses SHA384 as the
62	// handshake hash.
63	suiteSHA384
64	// suitePSK indicates that the cipher suite authenticates with
65	// a pre-shared key rather than a server private key.
66	suitePSK
67)
68
69type tlsAead struct {
70	cipher.AEAD
71	explicitNonce bool
72}
73
74// A cipherSuite is a specific combination of key agreement, cipher and MAC
75// function. All cipher suites currently assume RSA key agreement.
76type cipherSuite struct {
77	id uint16
78	// the lengths, in bytes, of the key material needed for each component.
79	keyLen int
80	macLen int
81	ivLen  func(version uint16) int
82	ka     func(version uint16) keyAgreement
83	// flags is a bitmask of the suite* values, above.
84	flags  int
85	cipher func(key, iv []byte, isRead bool) interface{}
86	mac    func(version uint16, macKey []byte) macFunction
87	aead   func(version uint16, key, fixedNonce []byte) *tlsAead
88}
89
90func (cs cipherSuite) hash() crypto.Hash {
91	if cs.flags&suiteSHA384 != 0 {
92		return crypto.SHA384
93	}
94	return crypto.SHA256
95}
96
97var cipherSuites = []*cipherSuite{
98	{TLS_CHACHA20_POLY1305_SHA256, 32, 0, ivLenChaCha20Poly1305, nil, suiteTLS13, nil, nil, aeadCHACHA20POLY1305},
99	{TLS_AES_128_GCM_SHA256, 16, 0, ivLenAESGCM, nil, suiteTLS13, nil, nil, aeadAESGCM},
100	{TLS_AES_256_GCM_SHA384, 32, 0, ivLenAESGCM, nil, suiteTLS13 | suiteSHA384, nil, nil, aeadAESGCM},
101	{TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 32, 0, ivLenChaCha20Poly1305, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadCHACHA20POLY1305},
102	{TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 32, 0, ivLenChaCha20Poly1305, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadCHACHA20POLY1305},
103	{TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 16, 0, ivLenAESGCM, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadAESGCM},
104	{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, ivLenAESGCM, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadAESGCM},
105	{TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 32, 0, ivLenAESGCM, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
106	{TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, 32, 0, ivLenAESGCM, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
107	{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, 16, 32, ivLenAES, ecdheRSAKA, suiteECDHE | suiteTLS12, cipherAES, macSHA256, nil},
108	{TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, 16, 32, ivLenAES, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, cipherAES, macSHA256, nil},
109	{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, 16, 20, ivLenAES, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
110	{TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, 16, 20, ivLenAES, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil},
111	{TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384, 32, 48, ivLenAES, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, cipherAES, macSHA384, nil},
112	{TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384, 32, 48, ivLenAES, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteSHA384, cipherAES, macSHA384, nil},
113	{TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, 32, 20, ivLenAES, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
114	{TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, 32, 20, ivLenAES, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil},
115	{TLS_RSA_WITH_AES_128_GCM_SHA256, 16, 0, ivLenAESGCM, rsaKA, suiteTLS12, nil, nil, aeadAESGCM},
116	{TLS_RSA_WITH_AES_256_GCM_SHA384, 32, 0, ivLenAESGCM, rsaKA, suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
117	{TLS_RSA_WITH_AES_128_CBC_SHA256, 16, 32, ivLenAES, rsaKA, suiteTLS12, cipherAES, macSHA256, nil},
118	{TLS_RSA_WITH_AES_256_CBC_SHA256, 32, 32, ivLenAES, rsaKA, suiteTLS12, cipherAES, macSHA256, nil},
119	{TLS_RSA_WITH_AES_128_CBC_SHA, 16, 20, ivLenAES, rsaKA, 0, cipherAES, macSHA1, nil},
120	{TLS_RSA_WITH_AES_256_CBC_SHA, 32, 20, ivLenAES, rsaKA, 0, cipherAES, macSHA1, nil},
121	{TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, ivLen3DES, ecdheRSAKA, suiteECDHE, cipher3DES, macSHA1, nil},
122	{TLS_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, ivLen3DES, rsaKA, 0, cipher3DES, macSHA1, nil},
123	{TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256, 32, 0, ivLenChaCha20Poly1305, ecdhePSKKA, suiteECDHE | suitePSK | suiteTLS12, nil, nil, aeadCHACHA20POLY1305},
124	{TLS_ECDHE_PSK_WITH_AES_128_CBC_SHA, 16, 20, ivLenAES, ecdhePSKKA, suiteECDHE | suitePSK, cipherAES, macSHA1, nil},
125	{TLS_ECDHE_PSK_WITH_AES_256_CBC_SHA, 32, 20, ivLenAES, ecdhePSKKA, suiteECDHE | suitePSK, cipherAES, macSHA1, nil},
126	{TLS_PSK_WITH_AES_128_CBC_SHA, 16, 20, ivLenAES, pskKA, suitePSK, cipherAES, macSHA1, nil},
127	{TLS_PSK_WITH_AES_256_CBC_SHA, 32, 20, ivLenAES, pskKA, suitePSK, cipherAES, macSHA1, nil},
128	{TLS_RSA_WITH_NULL_SHA, 0, 20, noIV, rsaKA, 0, cipherNull, macSHA1, nil},
129}
130
131func noIV(vers uint16) int {
132	return 0
133}
134
135func ivLenChaCha20Poly1305(vers uint16) int {
136	return 12
137}
138
139func ivLenAESGCM(vers uint16) int {
140	if vers >= VersionTLS13 {
141		return 12
142	}
143	return 4
144}
145
146func ivLenAES(vers uint16) int {
147	return 16
148}
149
150func ivLen3DES(vers uint16) int {
151	return 8
152}
153
154type nullCipher struct{}
155
156func cipherNull(key, iv []byte, isRead bool) interface{} {
157	return nullCipher{}
158}
159
160func cipher3DES(key, iv []byte, isRead bool) interface{} {
161	block, _ := des.NewTripleDESCipher(key)
162	if isRead {
163		return cipher.NewCBCDecrypter(block, iv)
164	}
165	return cipher.NewCBCEncrypter(block, iv)
166}
167
168func cipherAES(key, iv []byte, isRead bool) interface{} {
169	block, _ := aes.NewCipher(key)
170	if isRead {
171		return cipher.NewCBCDecrypter(block, iv)
172	}
173	return cipher.NewCBCEncrypter(block, iv)
174}
175
176// macSHA1 returns a macFunction for the given protocol version.
177func macSHA1(version uint16, key []byte) macFunction {
178	if version == VersionSSL30 {
179		mac := ssl30MAC{
180			h:   sha1.New(),
181			key: make([]byte, len(key)),
182		}
183		copy(mac.key, key)
184		return mac
185	}
186	return tls10MAC{hmac.New(sha1.New, key)}
187}
188
189func macMD5(version uint16, key []byte) macFunction {
190	if version == VersionSSL30 {
191		mac := ssl30MAC{
192			h:   md5.New(),
193			key: make([]byte, len(key)),
194		}
195		copy(mac.key, key)
196		return mac
197	}
198	return tls10MAC{hmac.New(md5.New, key)}
199}
200
201func macSHA256(version uint16, key []byte) macFunction {
202	if version == VersionSSL30 {
203		mac := ssl30MAC{
204			h:   sha256.New(),
205			key: make([]byte, len(key)),
206		}
207		copy(mac.key, key)
208		return mac
209	}
210	return tls10MAC{hmac.New(sha256.New, key)}
211}
212
213func macSHA384(version uint16, key []byte) macFunction {
214	if version == VersionSSL30 {
215		mac := ssl30MAC{
216			h:   sha512.New384(),
217			key: make([]byte, len(key)),
218		}
219		copy(mac.key, key)
220		return mac
221	}
222	return tls10MAC{hmac.New(sha512.New384, key)}
223}
224
225type macFunction interface {
226	Size() int
227	MAC(digestBuf, seq, header, length, data []byte) []byte
228}
229
230// fixedNonceAEAD wraps an AEAD and prefixes a fixed portion of the nonce to
231// each call.
232type fixedNonceAEAD struct {
233	// sealNonce and openNonce are buffers where the larger nonce will be
234	// constructed. Since a seal and open operation may be running
235	// concurrently, there is a separate buffer for each.
236	sealNonce, openNonce []byte
237	aead                 cipher.AEAD
238}
239
240func (f *fixedNonceAEAD) NonceSize() int { return 8 }
241func (f *fixedNonceAEAD) Overhead() int  { return f.aead.Overhead() }
242
243func (f *fixedNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
244	copy(f.sealNonce[len(f.sealNonce)-8:], nonce)
245	return f.aead.Seal(out, f.sealNonce, plaintext, additionalData)
246}
247
248func (f *fixedNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) {
249	copy(f.openNonce[len(f.openNonce)-8:], nonce)
250	return f.aead.Open(out, f.openNonce, plaintext, additionalData)
251}
252
253func aeadAESGCM(version uint16, key, fixedNonce []byte) *tlsAead {
254	aes, err := aes.NewCipher(key)
255	if err != nil {
256		panic(err)
257	}
258	aead, err := cipher.NewGCM(aes)
259	if err != nil {
260		panic(err)
261	}
262
263	nonce1, nonce2 := make([]byte, 12), make([]byte, 12)
264	copy(nonce1, fixedNonce)
265	copy(nonce2, fixedNonce)
266
267	if version >= VersionTLS13 {
268		return &tlsAead{&xorNonceAEAD{nonce1, nonce2, aead}, false}
269	}
270
271	return &tlsAead{&fixedNonceAEAD{nonce1, nonce2, aead}, true}
272}
273
274func xorSlice(out, in []byte) {
275	for i := range out {
276		out[i] ^= in[i]
277	}
278}
279
280// xorNonceAEAD wraps an AEAD and XORs a fixed portion of the nonce, left-padded
281// if necessary, each call.
282type xorNonceAEAD struct {
283	// sealNonce and openNonce are buffers where the larger nonce will be
284	// constructed. Since a seal and open operation may be running
285	// concurrently, there is a separate buffer for each.
286	sealNonce, openNonce []byte
287	aead                 cipher.AEAD
288}
289
290func (x *xorNonceAEAD) NonceSize() int { return 8 }
291func (x *xorNonceAEAD) Overhead() int  { return x.aead.Overhead() }
292
293func (x *xorNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
294	xorSlice(x.sealNonce[len(x.sealNonce)-len(nonce):], nonce)
295	ret := x.aead.Seal(out, x.sealNonce, plaintext, additionalData)
296	xorSlice(x.sealNonce[len(x.sealNonce)-len(nonce):], nonce)
297	return ret
298}
299
300func (x *xorNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) {
301	xorSlice(x.openNonce[len(x.openNonce)-len(nonce):], nonce)
302	ret, err := x.aead.Open(out, x.openNonce, plaintext, additionalData)
303	xorSlice(x.openNonce[len(x.openNonce)-len(nonce):], nonce)
304	return ret, err
305}
306
307func aeadCHACHA20POLY1305(version uint16, key, fixedNonce []byte) *tlsAead {
308	aead, err := newChaCha20Poly1305(key)
309	if err != nil {
310		panic(err)
311	}
312
313	nonce1, nonce2 := make([]byte, len(fixedNonce)), make([]byte, len(fixedNonce))
314	copy(nonce1, fixedNonce)
315	copy(nonce2, fixedNonce)
316
317	return &tlsAead{&xorNonceAEAD{nonce1, nonce2, aead}, false}
318}
319
320// ssl30MAC implements the SSLv3 MAC function, as defined in
321// www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt section 5.2.3.1
322type ssl30MAC struct {
323	h   hash.Hash
324	key []byte
325}
326
327func (s ssl30MAC) Size() int {
328	return s.h.Size()
329}
330
331var ssl30Pad1 = [48]byte{0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36}
332
333var ssl30Pad2 = [48]byte{0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c}
334
335func (s ssl30MAC) MAC(digestBuf, seq, header, length, data []byte) []byte {
336	padLength := 48
337	if s.h.Size() == 20 {
338		padLength = 40
339	}
340
341	s.h.Reset()
342	s.h.Write(s.key)
343	s.h.Write(ssl30Pad1[:padLength])
344	s.h.Write(seq)
345	s.h.Write(header[:1])
346	s.h.Write(length)
347	s.h.Write(data)
348	digestBuf = s.h.Sum(digestBuf[:0])
349
350	s.h.Reset()
351	s.h.Write(s.key)
352	s.h.Write(ssl30Pad2[:padLength])
353	s.h.Write(digestBuf)
354	return s.h.Sum(digestBuf[:0])
355}
356
357// tls10MAC implements the TLS 1.0 MAC function. RFC 2246, section 6.2.3.
358type tls10MAC struct {
359	h hash.Hash
360}
361
362func (s tls10MAC) Size() int {
363	return s.h.Size()
364}
365
366func (s tls10MAC) MAC(digestBuf, seq, header, length, data []byte) []byte {
367	s.h.Reset()
368	s.h.Write(seq)
369	s.h.Write(header)
370	s.h.Write(length)
371	s.h.Write(data)
372	return s.h.Sum(digestBuf[:0])
373}
374
375func rsaKA(version uint16) keyAgreement {
376	return &rsaKeyAgreement{version: version}
377}
378
379func ecdheECDSAKA(version uint16) keyAgreement {
380	return &ecdheKeyAgreement{
381		auth: &signedKeyAgreement{
382			keyType: keyTypeECDSA,
383			version: version,
384		},
385	}
386}
387
388func ecdheRSAKA(version uint16) keyAgreement {
389	return &ecdheKeyAgreement{
390		auth: &signedKeyAgreement{
391			keyType: keyTypeRSA,
392			version: version,
393		},
394	}
395}
396
397func pskKA(version uint16) keyAgreement {
398	return &pskKeyAgreement{
399		base: &nilKeyAgreement{},
400	}
401}
402
403func ecdhePSKKA(version uint16) keyAgreement {
404	return &pskKeyAgreement{
405		base: &ecdheKeyAgreement{
406			auth: &nilKeyAgreementAuthentication{},
407		},
408	}
409}
410
411// mutualCipherSuite returns a cipherSuite given a list of supported
412// ciphersuites and the id requested by the peer.
413func mutualCipherSuite(have []uint16, want uint16) *cipherSuite {
414	for _, id := range have {
415		if id == want {
416			return cipherSuiteFromID(id)
417		}
418	}
419	return nil
420}
421
422func cipherSuiteFromID(id uint16) *cipherSuite {
423	for _, suite := range cipherSuites {
424		if suite.id == id {
425			return suite
426		}
427	}
428	return nil
429}
430
431// A list of the possible cipher suite ids. Taken from
432// http://www.iana.org/assignments/tls-parameters/tls-parameters.xml
433const (
434	TLS_RSA_WITH_NULL_SHA                         uint16 = 0x0002
435	TLS_RSA_WITH_3DES_EDE_CBC_SHA                 uint16 = 0x000a
436	TLS_RSA_WITH_AES_128_CBC_SHA                  uint16 = 0x002f
437	TLS_RSA_WITH_AES_256_CBC_SHA                  uint16 = 0x0035
438	TLS_RSA_WITH_AES_128_CBC_SHA256               uint16 = 0x003c
439	TLS_RSA_WITH_AES_256_CBC_SHA256               uint16 = 0x003d
440	TLS_PSK_WITH_AES_128_CBC_SHA                  uint16 = 0x008c
441	TLS_PSK_WITH_AES_256_CBC_SHA                  uint16 = 0x008d
442	TLS_RSA_WITH_AES_128_GCM_SHA256               uint16 = 0x009c
443	TLS_RSA_WITH_AES_256_GCM_SHA384               uint16 = 0x009d
444	TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA          uint16 = 0xc009
445	TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA          uint16 = 0xc00a
446	TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA           uint16 = 0xc012
447	TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA            uint16 = 0xc013
448	TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA            uint16 = 0xc014
449	TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256       uint16 = 0xc023
450	TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384       uint16 = 0xc024
451	TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256         uint16 = 0xc027
452	TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384         uint16 = 0xc028
453	TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256       uint16 = 0xc02b
454	TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384       uint16 = 0xc02c
455	TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256         uint16 = 0xc02f
456	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384         uint16 = 0xc030
457	TLS_ECDHE_PSK_WITH_AES_128_CBC_SHA            uint16 = 0xc035
458	TLS_ECDHE_PSK_WITH_AES_256_CBC_SHA            uint16 = 0xc036
459	TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256   uint16 = 0xcca8
460	TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 uint16 = 0xcca9
461	TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256   uint16 = 0xccac
462	renegotiationSCSV                             uint16 = 0x00ff
463	fallbackSCSV                                  uint16 = 0x5600
464)
465
466// Additional cipher suite IDs, not IANA-assigned.
467const (
468	TLS_AES_128_GCM_SHA256       uint16 = 0x1301
469	TLS_AES_256_GCM_SHA384       uint16 = 0x1302
470	TLS_CHACHA20_POLY1305_SHA256 uint16 = 0x1303
471)
472