/*
* Copyright 2010-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.auth;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.util.Iterator;
import java.util.Map;
import java.util.SortedMap;
import java.util.TreeMap;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;
import com.amazonaws.AmazonClientException;
import com.amazonaws.Request;
import com.amazonaws.util.HttpUtils;
import com.amazonaws.util.StringInputStream;
/**
* Abstract base class for AWS signing protocol implementations. Provides
* utilities commonly needed by signing protocols such as computing
* canonicalized host names, query string parameters, etc.
* <p>
* Not intended to be sub-classed by developers.
*/
public abstract class AbstractAWSSigner implements Signer {
/** The default encoding to use when URL encoding */
protected static final String DEFAULT_ENCODING = "UTF-8";
/**
* Computes an RFC 2104-compliant HMAC signature and returns the result as a
* Base64 encoded string.
*/
protected String signAndBase64Encode(String data, String key, SigningAlgorithm algorithm)
throws AmazonClientException {
try {
return signAndBase64Encode(data.getBytes(DEFAULT_ENCODING), key, algorithm);
} catch (UnsupportedEncodingException e) {
throw new AmazonClientException("Unable to calculate a request signature: " + e.getMessage(), e);
}
}
/**
* Computes an RFC 2104-compliant HMAC signature for an array of bytes and
* returns the result as a Base64 encoded string.
*/
protected String signAndBase64Encode(byte[] data, String key, SigningAlgorithm algorithm)
throws AmazonClientException {
try {
byte[] signature = sign(data, key.getBytes(DEFAULT_ENCODING), algorithm);
return new String(Base64.encodeBase64(signature));
} catch (Exception e) {
throw new AmazonClientException("Unable to calculate a request signature: " + e.getMessage(), e);
}
}
protected byte[] sign(String stringData, byte[] key, SigningAlgorithm algorithm) throws AmazonClientException {
try {
byte[] data = stringData.getBytes(DEFAULT_ENCODING);
return sign(data, key, algorithm);
} catch (Exception e) {
throw new AmazonClientException("Unable to calculate a request signature: " + e.getMessage(), e);
}
}
protected byte[] sign(byte[] data, byte[] key, SigningAlgorithm algorithm) throws AmazonClientException {
try {
Mac mac = Mac.getInstance(algorithm.toString());
mac.init(new SecretKeySpec(key, algorithm.toString()));
return mac.doFinal(data);
} catch (Exception e) {
throw new AmazonClientException("Unable to calculate a request signature: " + e.getMessage(), e);
}
}
/**
* Hashes the string contents (assumed to be UTF-8) using the SHA-256
* algorithm.
*
* @param text
* The string to hash.
*
* @return The hashed bytes from the specified string.
*
* @throws AmazonClientException
* If the hash cannot be computed.
*/
protected byte[] hash(String text) throws AmazonClientException {
try {
MessageDigest md = MessageDigest.getInstance("SHA-256");
md.update(text.getBytes(DEFAULT_ENCODING));
return md.digest();
} catch (Exception e) {
throw new AmazonClientException("Unable to compute hash while signing request: " + e.getMessage(), e);
}
}
protected byte[] hash(InputStream input) throws AmazonClientException {
try {
MessageDigest md = MessageDigest.getInstance("SHA-256");
DigestInputStream digestInputStream = new DigestInputStream(input, md);
byte[] buffer = new byte[1024];
while (digestInputStream.read(buffer) > -1);
return digestInputStream.getMessageDigest().digest();
} catch (Exception e) {
throw new AmazonClientException("Unable to compute hash while signing request: " + e.getMessage(), e);
}
}
/**
* Hashes the binary data using the SHA-256 algorithm.
*
* @param data
* The binary data to hash.
*
* @return The hashed bytes from the specified data.
*
* @throws AmazonClientException
* If the hash cannot be computed.
*/
protected byte[] hash(byte[] data) throws AmazonClientException {
try {
MessageDigest md = MessageDigest.getInstance("SHA-256");
md.update(data);
return md.digest();
} catch (Exception e) {
throw new AmazonClientException("Unable to compute hash while signing request: " + e.getMessage(), e);
}
}
/**
* Examines the specified query string parameters and returns a
* canonicalized form.
* <p>
* The canonicalized query string is formed by first sorting all the query
* string parameters, then URI encoding both the key and value and then
* joining them, in order, separating key value pairs with an '&'.
*
* @param parameters
* The query string parameters to be canonicalized.
*
* @return A canonicalized form for the specified query string parameters.
*/
protected String getCanonicalizedQueryString(Map<String, String> parameters) {
SortedMap<String, String> sorted = new TreeMap<String, String>();
Iterator<Map.Entry<String, String>> pairs = parameters.entrySet().iterator();
while (pairs.hasNext()) {
Map.Entry<String, String> pair = pairs.next();
String key = pair.getKey();
String value = pair.getValue();
sorted.put(HttpUtils.urlEncode(key, false), HttpUtils.urlEncode(value, false));
}
StringBuilder builder = new StringBuilder();
pairs = sorted.entrySet().iterator();
while (pairs.hasNext()) {
Map.Entry<String, String> pair = pairs.next();
builder.append(pair.getKey());
builder.append("=");
builder.append(pair.getValue());
if (pairs.hasNext()) {
builder.append("&");
}
}
return builder.toString();
}
protected String getCanonicalizedQueryString(Request<?> request) {
/*
* If we're using POST and we don't have any request payload content,
* then any request query parameters will be sent as the payload, and
* not in the actual query string.
*/
if (HttpUtils.usePayloadForQueryParameters(request)) return "";
else return this.getCanonicalizedQueryString(request.getParameters());
}
/**
* Returns the request's payload as binary data.
*
* @param request
* The request
* @return The data from the request's payload, as binary data.
*/
protected byte[] getBinaryRequestPayload(Request<?> request) {
if (HttpUtils.usePayloadForQueryParameters(request)) {
String encodedParameters = HttpUtils.encodeParameters(request);
if (encodedParameters == null) return new byte[0];
try {
return encodedParameters.getBytes(DEFAULT_ENCODING);
} catch (UnsupportedEncodingException e) {
throw new AmazonClientException("Unable to encode string into bytes");
}
}
return getBinaryRequestPayloadWithoutQueryParams(request);
}
/**
* Returns the request's payload as a String.
*
* @param request
* The request
* @return The data from the request's payload, as a string.
*/
protected String getRequestPayload(Request<?> request) {
return newString(getBinaryRequestPayload(request));
}
/**
* Returns the request's payload contents as a String, without processing
* any query string params (i.e. no form encoding for query params).
*
* @param request
* The request
* @return the request's payload contents as a String, not including any
* form encoding of query string params.
*/
protected String getRequestPayloadWithoutQueryParams(Request<?> request) {
return newString(getBinaryRequestPayloadWithoutQueryParams(request));
}
/**
* Returns the request's payload contents as binary data, without processing
* any query string params (i.e. no form encoding for query params).
*
* @param request
* The request
* @return The request's payload contents as binary data, not including any
* form encoding of query string params.
*/
protected byte[] getBinaryRequestPayloadWithoutQueryParams(Request<?> request) {
InputStream content = getBinaryRequestPayloadStreamWithoutQueryParams(request);
try {
content.mark(-1);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024 * 5];
while (true) {
int bytesRead = content.read(buffer);
if (bytesRead == -1) break;
byteArrayOutputStream.write(buffer, 0, bytesRead);
}
byteArrayOutputStream.close();
content.reset();
return byteArrayOutputStream.toByteArray();
} catch (Exception e) {
throw new AmazonClientException("Unable to read request payload to sign request: " + e.getMessage(), e);
}
}
protected InputStream getBinaryRequestPayloadStream(Request<?> request) {
if (HttpUtils.usePayloadForQueryParameters(request)) {
String encodedParameters = HttpUtils.encodeParameters(request);
if (encodedParameters == null) return new ByteArrayInputStream(new byte[0]);
try {
return new ByteArrayInputStream(encodedParameters.getBytes(DEFAULT_ENCODING));
} catch (UnsupportedEncodingException e) {
throw new AmazonClientException("Unable to encode string into bytes");
}
}
return getBinaryRequestPayloadStreamWithoutQueryParams(request);
}
protected InputStream getBinaryRequestPayloadStreamWithoutQueryParams(Request<?> request) {
try {
InputStream content = request.getContent();
if (content == null) return new ByteArrayInputStream(new byte[0]);
if (content instanceof StringInputStream) {
return content;
}
if (!content.markSupported()) {
throw new AmazonClientException("Unable to read request payload to sign request.");
}
return request.getContent();
} catch (Exception e) {
throw new AmazonClientException("Unable to read request payload to sign request: " + e.getMessage(), e);
}
}
protected String getCanonicalizedResourcePath(String resourcePath) {
if (resourcePath == null || resourcePath.length() == 0) {
return "/";
} else {
return HttpUtils.urlEncode(resourcePath, true);
}
}
protected String getCanonicalizedEndpoint(URI endpoint) {
String endpointForStringToSign = endpoint.getHost().toLowerCase();
/*
* Apache HttpClient will omit the port in the Host header for default
* port values (i.e. 80 for HTTP and 443 for HTTPS) even if we
* explicitly specify it, so we need to be careful that we use the same
* value here when we calculate the string to sign and in the Host
* header we send in the HTTP request.
*/
if (HttpUtils.isUsingNonDefaultPort(endpoint)) {
endpointForStringToSign += ":" + endpoint.getPort();
}
return endpointForStringToSign;
}
/**
* Loads the individual access key ID and secret key from the specified
* credentials, ensuring that access to the credentials is synchronized on
* the credentials object itself, and trimming any extra whitespace from the
* credentials.
* <p>
* Returns either a {@link BasicSessionCredentials} or a
* {@link BasicAWSCredentials} object, depending on the input type.
*
* @param credentials
* @return A new credentials object with the sanitized credentials.
*/
protected AWSCredentials sanitizeCredentials(AWSCredentials credentials) {
String accessKeyId = null;
String secretKey = null;
String token = null;
synchronized (credentials) {
accessKeyId = credentials.getAWSAccessKeyId();
secretKey = credentials.getAWSSecretKey();
if ( credentials instanceof AWSSessionCredentials ) {
token = ((AWSSessionCredentials) credentials).getSessionToken();
}
}
if (secretKey != null) secretKey = secretKey.trim();
if (accessKeyId != null) accessKeyId = accessKeyId.trim();
if (token != null) token = token.trim();
if (credentials instanceof AWSSessionCredentials) {
return new BasicSessionCredentials(accessKeyId, secretKey, token);
}
return new BasicAWSCredentials(accessKeyId, secretKey);
}
/**
* Safely converts a UTF-8 encoded byte array into a String.
*
* @param bytes UTF-8 encoded binary character data.
*
* @return The converted String object.
*/
protected String newString(byte[] bytes) {
try {
return new String(bytes, "UTF-8");
} catch (UnsupportedEncodingException e) {
throw new AmazonClientException("Unable to encode bytes to String", e);
}
}
/**
* Adds session credentials to the request given.
*
* @param request
* The request to add session credentials information to
* @param credentials
* The session credentials to add to the request
*/
protected abstract void addSessionCredentials(Request<?> request, AWSSessionCredentials credentials);
}