1 /*
2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.security.ssl;
27
28 import java.io.IOException;
29 import java.nio.ByteBuffer;
30 import java.security.GeneralSecurityException;
31 import java.security.spec.AlgorithmParameterSpec;
32 import javax.crypto.SecretKey;
33 import javax.net.ssl.SSLHandshakeException;
34 import sun.security.ssl.CipherSuite.HashAlg;
35
36 final class SSLSecretDerivation implements SSLKeyDerivation {
37 private static final byte[] sha256EmptyDigest = new byte[] {
38 (byte)0xE3, (byte)0xB0, (byte)0xC4, (byte)0x42,
39 (byte)0x98, (byte)0xFC, (byte)0x1C, (byte)0x14,
40 (byte)0x9A, (byte)0xFB, (byte)0xF4, (byte)0xC8,
41 (byte)0x99, (byte)0x6F, (byte)0xB9, (byte)0x24,
42 (byte)0x27, (byte)0xAE, (byte)0x41, (byte)0xE4,
43 (byte)0x64, (byte)0x9B, (byte)0x93, (byte)0x4C,
44 (byte)0xA4, (byte)0x95, (byte)0x99, (byte)0x1B,
45 (byte)0x78, (byte)0x52, (byte)0xB8, (byte)0x55
46 };
47
48 private static final byte[] sha384EmptyDigest = new byte[] {
49 (byte)0x38, (byte)0xB0, (byte)0x60, (byte)0xA7,
50 (byte)0x51, (byte)0xAC, (byte)0x96, (byte)0x38,
51 (byte)0x4C, (byte)0xD9, (byte)0x32, (byte)0x7E,
52 (byte)0xB1, (byte)0xB1, (byte)0xE3, (byte)0x6A,
53 (byte)0x21, (byte)0xFD, (byte)0xB7, (byte)0x11,
54 (byte)0x14, (byte)0xBE, (byte)0x07, (byte)0x43,
55 (byte)0x4C, (byte)0x0C, (byte)0xC7, (byte)0xBF,
56 (byte)0x63, (byte)0xF6, (byte)0xE1, (byte)0xDA,
57 (byte)0x27, (byte)0x4E, (byte)0xDE, (byte)0xBF,
58 (byte)0xE7, (byte)0x6F, (byte)0x65, (byte)0xFB,
59 (byte)0xD5, (byte)0x1A, (byte)0xD2, (byte)0xF1,
60 (byte)0x48, (byte)0x98, (byte)0xB9, (byte)0x5B
61 };
62
63 private final HandshakeContext context;
64 private final String hkdfAlg;
65 private final HashAlg hashAlg;
66 private final SecretKey secret;
67 private final byte[] transcriptHash; // handshake messages transcript hash
68
69 SSLSecretDerivation(
70 HandshakeContext context, SecretKey secret) {
71 this.context = context;
72 this.secret = secret;
73 // TODO: May need the hash algogorithm if the secret is a PSK.
74 // if (secret is a PSK) {
75 // ...
76 // } else {
77 this.hashAlg = context.negotiatedCipherSuite.hashAlg;
78 this.hkdfAlg =
79 "HKDF-Expand/Hmac" + hashAlg.name.replace("-", "");
80 context.handshakeHash.update();
81 this.transcriptHash = context.handshakeHash.digest();
82 // }
83 }
84
85 SSLSecretDerivation forContext(HandshakeContext context) {
86 return new SSLSecretDerivation(context, secret);
87 }
88
89 @Override
90 public SecretKey deriveKey(String algorithm,
91 AlgorithmParameterSpec params) throws IOException {
92 SecretSchedule ks = SecretSchedule.valueOf(algorithm);
93 try {
94 byte[] expandContext;
95 if (ks == SecretSchedule.TlsSaltSecret) {
96 if (hashAlg == HashAlg.H_SHA256) {
97 expandContext = sha256EmptyDigest;
98 } else if (hashAlg == HashAlg.H_SHA384) {
99 expandContext = sha384EmptyDigest;
100 } else {
101 // unlikely, but please update if more hash algorithm
102 // get supported in the future.
103 expandContext = new byte[0];
104 }
105 } else {
106 expandContext = transcriptHash;
107 }
108 byte[] hkdfInfo = createHkdfInfo(ks.label,
109 expandContext, hashAlg.hashLength);
110
111 HKDF hkdf = new HKDF(hashAlg.name);
112 return hkdf.expand(secret, hkdfInfo, hashAlg.hashLength, algorithm);
113 } catch (GeneralSecurityException gse) {
114 throw (SSLHandshakeException) new SSLHandshakeException(
115 "Could not generate secret").initCause(gse);
116 }
117 }
118
119 public static byte[] createHkdfInfo(
120 byte[] label, byte[] context, int length) {
121 byte[] info = new byte[4 + label.length + context.length];
122 ByteBuffer m = ByteBuffer.wrap(info);
123 try {
124 Record.putInt16(m, length);
125 Record.putBytes8(m, label);
126 Record.putBytes8(m, context);
127 } catch (IOException ioe) {
128 // unlikely
129 }
130
131 return info;
132 }
133
134 private enum SecretSchedule {
135 // Note that we use enum name as the key/secret name.
136 TlsSaltSecret ("derived"),
137 TlsExtBinderKey ("ext binder"),
138 TlsResBinderKey ("res binder"),
139 TlsClientEarlyTrafficSecret ("c e traffic"),
140 TlsEarlyExporterMasterSecret ("e exp master"),
141 TlsClientHandshakeTrafficSecret ("c hs traffic"),
142 TlsServerHandshakeTrafficSecret ("s hs traffic"),
143 TlsClientAppTrafficSecret ("c ap traffic"),
144 TlsServerAppTrafficSecret ("s ap traffic"),
145 TlsExporterMasterSecret ("exp master"),
146 TlsResumptionMasterSecret ("res master");
147
148 private final byte[] label;
149
150 private SecretSchedule(String label) {
151 this.label = ("tls13 " + label).getBytes();
152 }
153 }
154 }