SaslInputStream.java
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.hadoop.security;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.InputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import javax.security.sasl.Sasl;
import javax.security.sasl.SaslClient;
import javax.security.sasl.SaslException;
import javax.security.sasl.SaslServer;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A SaslInputStream is composed of an InputStream and a SaslServer (or
* SaslClient) so that read() methods return data that are read in from the
* underlying InputStream but have been additionally processed by the SaslServer
* (or SaslClient) object. The SaslServer (or SaslClient) object must be fully
* initialized before being used by a SaslInputStream.
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Evolving
public class SaslInputStream extends InputStream implements ReadableByteChannel {
public static final Logger LOG =
LoggerFactory.getLogger(SaslInputStream.class);
private final DataInputStream inStream;
/** Should we wrap the communication channel? */
private final boolean useWrap;
/*
* data read from the underlying input stream before being processed by SASL
*/
private byte[] saslToken;
private final SaslClient saslClient;
private final SaslServer saslServer;
private byte[] lengthBuf = new byte[4];
/*
* buffer holding data that have been processed by SASL, but have not been
* read out
*/
private byte[] obuffer;
// position of the next "new" byte
private int ostart = 0;
// position of the last "new" byte
private int ofinish = 0;
// whether or not this stream is open
private boolean isOpen = true;
private static int unsignedBytesToInt(byte[] buf) {
if (buf.length != 4) {
throw new IllegalArgumentException(
"Cannot handle byte array other than 4 bytes");
}
int result = 0;
for (int i = 0; i < 4; i++) {
result <<= 8;
result |= ((int) buf[i] & 0xff);
}
return result;
}
/**
* Read more data and get them processed <br>
* Entry condition: ostart = ofinish <br>
* Exit condition: ostart <= ofinish <br>
*
* return (ofinish-ostart) (we have this many bytes for you), 0 (no data now,
* but could have more later), or -1 (absolutely no more data)
*/
private int readMoreData() throws IOException {
try {
inStream.readFully(lengthBuf);
int length = unsignedBytesToInt(lengthBuf);
if (LOG.isDebugEnabled())
LOG.debug("Actual length is " + length);
saslToken = new byte[length];
inStream.readFully(saslToken);
} catch (EOFException e) {
return -1;
}
try {
if (saslServer != null) { // using saslServer
obuffer = saslServer.unwrap(saslToken, 0, saslToken.length);
} else { // using saslClient
obuffer = saslClient.unwrap(saslToken, 0, saslToken.length);
}
} catch (SaslException se) {
try {
disposeSasl();
} catch (SaslException ignored) {
}
throw se;
}
ostart = 0;
if (obuffer == null)
ofinish = 0;
else
ofinish = obuffer.length;
return ofinish;
}
/**
* Disposes of any system resources or security-sensitive information Sasl
* might be using.
*
* @exception SaslException
* if a SASL error occurs.
*/
private void disposeSasl() throws SaslException {
if (saslClient != null) {
saslClient.dispose();
}
if (saslServer != null) {
saslServer.dispose();
}
}
/**
* Constructs a SASLInputStream from an InputStream and a SaslServer <br>
* Note: if the specified InputStream or SaslServer is null, a
* NullPointerException may be thrown later when they are used.
*
* @param inStream
* the InputStream to be processed
* @param saslServer
* an initialized SaslServer object
*/
public SaslInputStream(InputStream inStream, SaslServer saslServer) {
this.inStream = new DataInputStream(inStream);
this.saslServer = saslServer;
this.saslClient = null;
String qop = (String) saslServer.getNegotiatedProperty(Sasl.QOP);
this.useWrap = qop != null && !"auth".equalsIgnoreCase(qop);
}
/**
* Constructs a SASLInputStream from an InputStream and a SaslClient <br>
* Note: if the specified InputStream or SaslClient is null, a
* NullPointerException may be thrown later when they are used.
*
* @param inStream
* the InputStream to be processed
* @param saslClient
* an initialized SaslClient object
*/
public SaslInputStream(InputStream inStream, SaslClient saslClient) {
this.inStream = new DataInputStream(inStream);
this.saslServer = null;
this.saslClient = saslClient;
String qop = (String) saslClient.getNegotiatedProperty(Sasl.QOP);
this.useWrap = qop != null && !"auth".equalsIgnoreCase(qop);
}
/**
* Reads the next byte of data from this input stream. The value byte is
* returned as an <code>int</code> in the range <code>0</code> to
* <code>255</code>. If no byte is available because the end of the stream has
* been reached, the value <code>-1</code> is returned. This method blocks
* until input data is available, the end of the stream is detected, or an
* exception is thrown.
* <p>
*
* @return the next byte of data, or <code>-1</code> if the end of the stream
* is reached.
* @exception IOException
* if an I/O error occurs.
*/
@Override
public int read() throws IOException {
if (!useWrap) {
return inStream.read();
}
if (ostart >= ofinish) {
// we loop for new data as we are blocking
int i = 0;
while (i == 0)
i = readMoreData();
if (i == -1)
return -1;
}
return ((int) obuffer[ostart++] & 0xff);
}
/**
* Reads up to <code>b.length</code> bytes of data from this input stream into
* an array of bytes.
* <p>
* The <code>read</code> method of <code>InputStream</code> calls the
* <code>read</code> method of three arguments with the arguments
* <code>b</code>, <code>0</code>, and <code>b.length</code>.
*
* @param b
* the buffer into which the data is read.
* @return the total number of bytes read into the buffer, or <code>-1</code>
* is there is no more data because the end of the stream has been
* reached.
* @exception IOException
* if an I/O error occurs.
*/
@Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
/**
* Reads up to <code>len</code> bytes of data from this input stream into an
* array of bytes. This method blocks until some input is available. If the
* first argument is <code>null,</code> up to <code>len</code> bytes are read
* and discarded.
*
* @param b
* the buffer into which the data is read.
* @param off
* the start offset of the data.
* @param len
* the maximum number of bytes read.
* @return the total number of bytes read into the buffer, or <code>-1</code>
* if there is no more data because the end of the stream has been
* reached.
* @exception IOException
* if an I/O error occurs.
*/
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (len == 0) {
return 0;
}
if (!useWrap) {
return inStream.read(b, off, len);
}
if (ostart >= ofinish) {
// we loop for new data as we are blocking
int i = 0;
while (i == 0)
i = readMoreData();
if (i == -1)
return -1;
}
if (len <= 0) {
return 0;
}
int available = ofinish - ostart;
if (len < available)
available = len;
if (b != null) {
System.arraycopy(obuffer, ostart, b, off, available);
}
ostart = ostart + available;
return available;
}
/**
* Skips <code>n</code> bytes of input from the bytes that can be read from
* this input stream without blocking.
*
* <p>
* Fewer bytes than requested might be skipped. The actual number of bytes
* skipped is equal to <code>n</code> or the result of a call to
* {@link #available()}, whichever is smaller. If
* <code>n</code> is less than zero, no bytes are skipped.
*
* <p>
* The actual number of bytes skipped is returned.
*
* @param n
* the number of bytes to be skipped.
* @return the actual number of bytes skipped.
* @exception IOException
* if an I/O error occurs.
*/
@Override
public long skip(long n) throws IOException {
if (!useWrap) {
return inStream.skip(n);
}
int available = ofinish - ostart;
if (n > available) {
n = available;
}
if (n < 0) {
return 0;
}
ostart += n;
return n;
}
/**
* Returns the number of bytes that can be read from this input stream without
* blocking. The <code>available</code> method of <code>InputStream</code>
* returns <code>0</code>. This method <B>should</B> be overridden by
* subclasses.
*
* @return the number of bytes that can be read from this input stream without
* blocking.
* @exception IOException
* if an I/O error occurs.
*/
@Override
public int available() throws IOException {
if (!useWrap) {
return inStream.available();
}
return (ofinish - ostart);
}
/**
* Closes this input stream and releases any system resources associated with
* the stream.
* <p>
* The <code>close</code> method of <code>SASLInputStream</code> calls the
* <code>close</code> method of its underlying input stream.
*
* @exception IOException
* if an I/O error occurs.
*/
@Override
public void close() throws IOException {
disposeSasl();
ostart = 0;
ofinish = 0;
inStream.close();
isOpen = false;
}
/**
* Tests if this input stream supports the <code>mark</code> and
* <code>reset</code> methods, which it does not.
*
* @return <code>false</code>, since this class does not support the
* <code>mark</code> and <code>reset</code> methods.
*/
@Override
public boolean markSupported() {
return false;
}
@Override
public boolean isOpen() {
return isOpen;
}
@Override
public int read(ByteBuffer dst) throws IOException {
int bytesRead = 0;
if (dst.hasArray()) {
bytesRead = read(dst.array(), dst.arrayOffset() + dst.position(),
dst.remaining());
if (bytesRead > -1) {
dst.position(dst.position() + bytesRead);
}
} else {
byte[] buf = new byte[dst.remaining()];
bytesRead = read(buf);
if (bytesRead > -1) {
dst.put(buf, 0, bytesRead);
}
}
return bytesRead;
}
}