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| 1 | /* | ||
| 2 | * Copyright (c) 1997, 2011, 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 java.security; | ||
| 27 | |||
| 28 | import java.io.*; | ||
| 29 | |||
| 30 | /** | ||
| 31 | * <p> SignedObject is a class for the purpose of creating authentic | ||
| 32 | * runtime objects whose integrity cannot be compromised without being | ||
| 33 | * detected. | ||
| 34 | * | ||
| 35 | * <p> More specifically, a SignedObject contains another Serializable | ||
| 36 | * object, the (to-be-)signed object and its signature. | ||
| 37 | * | ||
| 38 | * <p> The signed object is a "deep copy" (in serialized form) of an | ||
| 39 | * original object. Once the copy is made, further manipulation of | ||
| 40 | * the original object has no side effect on the copy. | ||
| 41 | * | ||
| 42 | * <p> The underlying signing algorithm is designated by the Signature | ||
| 43 | * object passed to the constructor and the <code>verify</code> method. | ||
| 44 | * A typical usage for signing is the following: | ||
| 45 | * | ||
| 46 | * <p> <code> <pre> | ||
| 47 | * Signature signingEngine = Signature.getInstance(algorithm, | ||
| 48 | * provider); | ||
| 49 | * SignedObject so = new SignedObject(myobject, signingKey, | ||
| 50 | * signingEngine); | ||
| 51 | * </pre> </code> | ||
| 52 | * | ||
| 53 | * <p> A typical usage for verification is the following (having | ||
| 54 | * received SignedObject <code>so</code>): | ||
| 55 | * | ||
| 56 | * <p> <code> <pre> | ||
| 57 | * Signature verificationEngine = | ||
| 58 | * Signature.getInstance(algorithm, provider); | ||
| 59 | * if (so.verify(publickey, verificationEngine)) | ||
| 60 | * try { | ||
| 61 | * Object myobj = so.getObject(); | ||
| 62 | * } catch (java.lang.ClassNotFoundException e) {}; | ||
| 63 | * </pre> </code> | ||
| 64 | * | ||
| 65 | * <p> Several points are worth noting. First, there is no need to | ||
| 66 | * initialize the signing or verification engine, as it will be | ||
| 67 | * re-initialized inside the constructor and the <code>verify</code> | ||
| 68 | * method. Secondly, for verification to succeed, the specified | ||
| 69 | * public key must be the public key corresponding to the private key | ||
| 70 | * used to generate the SignedObject. | ||
| 71 | * | ||
| 72 | * <p> More importantly, for flexibility reasons, the | ||
| 73 | * constructor and <code>verify</code> method allow for | ||
| 74 | * customized signature engines, which can implement signature | ||
| 75 | * algorithms that are not installed formally as part of a crypto | ||
| 76 | * provider. However, it is crucial that the programmer writing the | ||
| 77 | * verifier code be aware what <code>Signature</code> engine is being | ||
| 78 | * used, as its own implementation of the <code>verify</code> method | ||
| 79 | * is invoked to verify a signature. In other words, a malicious | ||
| 80 | * <code>Signature</code> may choose to always return true on | ||
| 81 | * verification in an attempt to bypass a security check. | ||
| 82 | * | ||
| 83 | * <p> The signature algorithm can be, among others, the NIST standard | ||
| 84 | * DSA, using DSA and SHA-1. The algorithm is specified using the | ||
| 85 | * same convention as that for signatures. The DSA algorithm using the | ||
| 86 | * SHA-1 message digest algorithm can be specified, for example, as | ||
| 87 | * "SHA/DSA" or "SHA-1/DSA" (they are equivalent). In the case of | ||
| 88 | * RSA, there are multiple choices for the message digest algorithm, | ||
| 89 | * so the signing algorithm could be specified as, for example, | ||
| 90 | * "MD2/RSA", "MD5/RSA" or "SHA-1/RSA". The algorithm name must be | ||
| 91 | * specified, as there is no default. | ||
| 92 | * | ||
| 93 | * <p> The name of the Cryptography Package Provider is designated | ||
| 94 | * also by the Signature parameter to the constructor and the | ||
| 95 | * <code>verify</code> method. If the provider is not | ||
| 96 | * specified, the default provider is used. Each installation can | ||
| 97 | * be configured to use a particular provider as default. | ||
| 98 | * | ||
| 99 | * <p> Potential applications of SignedObject include: | ||
| 100 | * <ul> | ||
| 101 | * <li> It can be used | ||
| 102 | * internally to any Java runtime as an unforgeable authorization | ||
| 103 | * token -- one that can be passed around without the fear that the | ||
| 104 | * token can be maliciously modified without being detected. | ||
| 105 | * <li> It | ||
| 106 | * can be used to sign and serialize data/object for storage outside | ||
| 107 | * the Java runtime (e.g., storing critical access control data on | ||
| 108 | * disk). | ||
| 109 | * <li> Nested SignedObjects can be used to construct a logical | ||
| 110 | * sequence of signatures, resembling a chain of authorization and | ||
| 111 | * delegation. | ||
| 112 | * </ul> | ||
| 113 | * | ||
| 114 | * @see Signature | ||
| 115 | * | ||
| 116 | * @author Li Gong | ||
| 117 | */ | ||
| 118 | |||
| 119 | public final class SignedObject implements Serializable { | ||
| 120 | |||
| 121 | private static final long serialVersionUID = 720502720485447167L; | ||
| 122 | |||
| 123 | /* | ||
| 124 | * The original content is "deep copied" in its serialized format | ||
| 125 | * and stored in a byte array. The signature field is also in the | ||
| 126 | * form of byte array. | ||
| 127 | */ | ||
| 128 | |||
| 129 | private byte[] content; | ||
| 130 | private byte[] signature; | ||
| 131 | private String thealgorithm; | ||
| 132 | |||
| 133 | /** | ||
| 134 | * Constructs a SignedObject from any Serializable object. | ||
| 135 | * The given object is signed with the given signing key, using the | ||
| 136 | * designated signature engine. | ||
| 137 | * | ||
| 138 | * @param object the object to be signed. | ||
| 139 | * @param signingKey the private key for signing. | ||
| 140 | * @param signingEngine the signature signing engine. | ||
| 141 | * | ||
| 142 | * @exception IOException if an error occurs during serialization | ||
| 143 | * @exception InvalidKeyException if the key is invalid. | ||
| 144 | * @exception SignatureException if signing fails. | ||
| 145 | */ | ||
| 146 | public SignedObject(Serializable object, PrivateKey signingKey, | ||
| 147 | Signature signingEngine) | ||
| 148 | throws IOException, InvalidKeyException, SignatureException { | ||
| 149 | // creating a stream pipe-line, from a to b | ||
| 150 | ByteArrayOutputStream b = new ByteArrayOutputStream(); | ||
| 151 | ObjectOutput a = new ObjectOutputStream(b); | ||
| 152 | |||
| 153 | // write and flush the object content to byte array | ||
| 154 | a.writeObject(object); | ||
| 155 | a.flush(); | ||
| 156 | a.close(); | ||
| 157 | this.content = b.toByteArray(); | ||
| 158 | b.close(); | ||
| 159 | |||
| 160 | // now sign the encapsulated object | ||
| 161 | this.sign(signingKey, signingEngine); | ||
| 162 | } | ||
| 163 | |||
| 164 | /** | ||
| 165 | * Retrieves the encapsulated object. | ||
| 166 | * The encapsulated object is de-serialized before it is returned. | ||
| 167 | * | ||
| 168 | * @return the encapsulated object. | ||
| 169 | * | ||
| 170 | * @exception IOException if an error occurs during de-serialization | ||
| 171 | * @exception ClassNotFoundException if an error occurs during | ||
| 172 | * de-serialization | ||
| 173 | */ | ||
| 174 | public Object getObject() | ||
| 175 | throws IOException, ClassNotFoundException | ||
| 176 | { | ||
| 177 | // creating a stream pipe-line, from b to a | ||
| 178 | ByteArrayInputStream b = new ByteArrayInputStream(this.content); | ||
| 179 | ObjectInput a = new ObjectInputStream(b); | ||
| 180 | Object obj = a.readObject(); | ||
| 181 | b.close(); | ||
| 182 | a.close(); | ||
| 183 | return obj; | ||
| 184 | } | ||
| 185 | |||
| 186 | /** | ||
| 187 | * Retrieves the signature on the signed object, in the form of a | ||
| 188 | * byte array. | ||
| 189 | * | ||
| 190 | * @return the signature. Returns a new array each time this | ||
| 191 | * method is called. | ||
| 192 | */ | ||
| 193 | public byte[] getSignature() { | ||
| 194 | return this.signature.clone(); | ||
| 195 | } | ||
| 196 | |||
| 197 | /** | ||
| 198 | * Retrieves the name of the signature algorithm. | ||
| 199 | * | ||
| 200 | * @return the signature algorithm name. | ||
| 201 | */ | ||
| 202 | public String getAlgorithm() { | ||
| 203 | return this.thealgorithm; | ||
| 204 | } | ||
| 205 | |||
| 206 | /** | ||
| 207 | * Verifies that the signature in this SignedObject is the valid | ||
| 208 | * signature for the object stored inside, with the given | ||
| 209 | * verification key, using the designated verification engine. | ||
| 210 | * | ||
| 211 | * @param verificationKey the public key for verification. | ||
| 212 | * @param verificationEngine the signature verification engine. | ||
| 213 | * | ||
| 214 | * @exception SignatureException if signature verification failed. | ||
| 215 | * @exception InvalidKeyException if the verification key is invalid. | ||
| 216 | * | ||
| 217 | * @return <tt>true</tt> if the signature | ||
| 218 | * is valid, <tt>false</tt> otherwise | ||
| 219 | */ | ||
| 220 | public boolean verify(PublicKey verificationKey, | ||
| 221 | Signature verificationEngine) | ||
| 222 | throws InvalidKeyException, SignatureException { | ||
| 223 | verificationEngine.initVerify(verificationKey); | ||
| 224 | verificationEngine.update(this.content.clone()); | ||
| 225 | return verificationEngine.verify(this.signature.clone()); | ||
| 226 | } | ||
| 227 | |||
| 228 | /* | ||
| 229 | * Signs the encapsulated object with the given signing key, using the | ||
| 230 | * designated signature engine. | ||
| 231 | * | ||
| 232 | * @param signingKey the private key for signing. | ||
| 233 | * @param signingEngine the signature signing engine. | ||
| 234 | * | ||
| 235 | * @exception InvalidKeyException if the key is invalid. | ||
| 236 | * @exception SignatureException if signing fails. | ||
| 237 | */ | ||
| 238 | private void sign(PrivateKey signingKey, Signature signingEngine) | ||
| 239 | throws InvalidKeyException, SignatureException { | ||
| 240 | // initialize the signing engine | ||
| 241 | signingEngine.initSign(signingKey); | ||
| 242 | signingEngine.update(this.content.clone()); | ||
| 243 | this.signature = signingEngine.sign().clone(); | ||
| 244 | this.thealgorithm = signingEngine.getAlgorithm(); | ||
| 245 | } | ||
| 246 | |||
| 247 | /** | ||
| 248 | * readObject is called to restore the state of the SignedObject from | ||
| 249 | * a stream. | ||
| 250 | */ | ||
| 251 | private void readObject(java.io.ObjectInputStream s) | ||
| 252 | throws java.io.IOException, ClassNotFoundException { | ||
| 253 | java.io.ObjectInputStream.GetField fields = s.readFields(); | ||
| 254 | content = ((byte[])fields.get("content", null)).clone(); | ||
| 255 | signature = ((byte[])fields.get("signature", null)).clone(); | ||
| 256 | thealgorithm = (String)fields.get("thealgorithm", null); | ||
| 257 | } | ||
| 258 | } | ||