| /* |
| * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.security.pkcs11; |
| |
| import java.util.*; |
| import java.io.*; |
| import java.security.*; |
| |
| import sun.security.pkcs11.wrapper.*; |
| import sun.security.pkcs11.wrapper.PKCS11Constants.*; |
| |
| /** |
| * SecureRandom implementation class. Some tokens support only |
| * C_GenerateRandom() and not C_SeedRandom(). In order not to lose an |
| * application specified seed, we create a SHA1PRNG that we mix with in that |
| * case. |
| * |
| * Note that since SecureRandom is thread safe, we only need one |
| * instance per PKCS#11 token instance. It is created on demand and cached |
| * in the SunPKCS11 class. |
| * |
| * Also note that we obtain the PKCS#11 session on demand, no need to tie one |
| * up. |
| * |
| * @author Andreas Sterbenz |
| * @since 1.5 |
| */ |
| final class P11SecureRandom extends SecureRandomSpi { |
| |
| private static final long serialVersionUID = -8939510236124553291L; |
| |
| // token instance |
| private final Token token; |
| |
| // PRNG for mixing, non-null if active (i.e. setSeed() has been called) |
| private volatile SecureRandom mixRandom; |
| |
| // buffer, if mixing is used |
| private byte[] mixBuffer; |
| |
| // bytes remaining in mixBuffer, if mixing is used |
| private int buffered; |
| |
| /* |
| * we buffer data internally for efficiency but limit the lifetime |
| * to avoid using stale bits. |
| */ |
| // lifetime in ms, currently 100 ms (0.1 s) |
| private static final long MAX_IBUFFER_TIME = 100; |
| |
| // size of the internal buffer |
| private static final int IBUFFER_SIZE = 32; |
| |
| // internal buffer for the random bits |
| private transient byte[] iBuffer = new byte[IBUFFER_SIZE]; |
| |
| // number of bytes remain in iBuffer |
| private transient int ibuffered = 0; |
| |
| // time that data was read into iBuffer |
| private transient long lastRead = 0L; |
| |
| P11SecureRandom(Token token) { |
| this.token = token; |
| } |
| |
| // see JCA spec |
| protected synchronized void engineSetSeed(byte[] seed) { |
| if (seed == null) { |
| throw new NullPointerException("seed must not be null"); |
| } |
| Session session = null; |
| try { |
| session = token.getOpSession(); |
| token.p11.C_SeedRandom(session.id(), seed); |
| } catch (PKCS11Exception e) { |
| // cannot set seed |
| // let a SHA1PRNG use that seed instead |
| SecureRandom random = mixRandom; |
| if (random != null) { |
| random.setSeed(seed); |
| } else { |
| try { |
| mixBuffer = new byte[20]; |
| random = SecureRandom.getInstance("SHA1PRNG"); |
| // initialize object before assigning to class field |
| random.setSeed(seed); |
| mixRandom = random; |
| } catch (NoSuchAlgorithmException ee) { |
| throw new ProviderException(ee); |
| } |
| } |
| } finally { |
| token.releaseSession(session); |
| } |
| } |
| |
| // see JCA spec |
| protected void engineNextBytes(byte[] bytes) { |
| if ((bytes == null) || (bytes.length == 0)) { |
| return; |
| } |
| if (bytes.length <= IBUFFER_SIZE) { |
| int ofs = 0; |
| synchronized (iBuffer) { |
| while (ofs < bytes.length) { |
| long time = System.currentTimeMillis(); |
| // refill the internal buffer if empty or stale |
| if ((ibuffered == 0) || |
| !(time - lastRead < MAX_IBUFFER_TIME)) { |
| lastRead = time; |
| implNextBytes(iBuffer); |
| ibuffered = IBUFFER_SIZE; |
| } |
| // copy the buffered bytes into 'bytes' |
| while ((ofs < bytes.length) && (ibuffered > 0)) { |
| bytes[ofs++] = iBuffer[IBUFFER_SIZE - ibuffered--]; |
| } |
| } |
| } |
| } else { |
| // avoid using the buffer - just fill bytes directly |
| implNextBytes(bytes); |
| } |
| |
| } |
| |
| // see JCA spec |
| protected byte[] engineGenerateSeed(int numBytes) { |
| byte[] b = new byte[numBytes]; |
| engineNextBytes(b); |
| return b; |
| } |
| |
| private void mix(byte[] b) { |
| SecureRandom random = mixRandom; |
| if (random == null) { |
| // avoid mixing if setSeed() has never been called |
| return; |
| } |
| synchronized (this) { |
| int ofs = 0; |
| int len = b.length; |
| while (len-- > 0) { |
| if (buffered == 0) { |
| random.nextBytes(mixBuffer); |
| buffered = mixBuffer.length; |
| } |
| b[ofs++] ^= mixBuffer[mixBuffer.length - buffered]; |
| buffered--; |
| } |
| } |
| } |
| |
| // fill up the specified buffer with random bytes, and mix them |
| private void implNextBytes(byte[] bytes) { |
| Session session = null; |
| try { |
| session = token.getOpSession(); |
| token.p11.C_GenerateRandom(session.id(), bytes); |
| mix(bytes); |
| } catch (PKCS11Exception e) { |
| throw new ProviderException("nextBytes() failed", e); |
| } finally { |
| token.releaseSession(session); |
| } |
| } |
| |
| private void readObject(ObjectInputStream in) |
| throws IOException, ClassNotFoundException { |
| in.defaultReadObject(); |
| // assign default values to non-null transient fields |
| iBuffer = new byte[IBUFFER_SIZE]; |
| ibuffered = 0; |
| lastRead = 0L; |
| } |
| } |