michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.sync.net;
michael@0: 
michael@0: import java.io.UnsupportedEncodingException;
michael@0: import java.net.URI;
michael@0: import java.security.GeneralSecurityException;
michael@0: import java.security.InvalidKeyException;
michael@0: import java.security.NoSuchAlgorithmException;
michael@0: 
michael@0: import javax.crypto.Mac;
michael@0: import javax.crypto.spec.SecretKeySpec;
michael@0: 
michael@0: import org.mozilla.apache.commons.codec.binary.Base64;
michael@0: import org.mozilla.gecko.background.common.log.Logger;
michael@0: import org.mozilla.gecko.sync.Utils;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.Header;
michael@0: import ch.boye.httpclientandroidlib.client.methods.HttpRequestBase;
michael@0: import ch.boye.httpclientandroidlib.client.methods.HttpUriRequest;
michael@0: import ch.boye.httpclientandroidlib.impl.client.DefaultHttpClient;
michael@0: import ch.boye.httpclientandroidlib.message.BasicHeader;
michael@0: import ch.boye.httpclientandroidlib.protocol.BasicHttpContext;
michael@0: 
michael@0: /**
michael@0:  * An <code>AuthHeaderProvider</code> that returns an Authorization header for
michael@0:  * HMAC-SHA1-signed requests in the format expected by Mozilla Services
michael@0:  * identity-attached services and specified by the MAC Authentication spec, available at
michael@0:  * <a href="https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac">https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac</a>.
michael@0:  * <p>
michael@0:  * See <a href="https://wiki.mozilla.org/Services/Sagrada/ServiceClientFlow#Access">https://wiki.mozilla.org/Services/Sagrada/ServiceClientFlow#Access</a>.
michael@0:  */
michael@0: public class HMACAuthHeaderProvider implements AuthHeaderProvider {
michael@0:   public static final String LOG_TAG = "HMACAuthHeaderProvider";
michael@0: 
michael@0:   public static final int NONCE_LENGTH_IN_BYTES = 8;
michael@0: 
michael@0:   public static final String HMAC_SHA1_ALGORITHM = "hmacSHA1";
michael@0: 
michael@0:   public final String identifier;
michael@0:   public final String key;
michael@0: 
michael@0:   public HMACAuthHeaderProvider(String identifier, String key) {
michael@0:     // Validate identifier string.  From the MAC Authentication spec:
michael@0:     // id             = "id" "=" string-value
michael@0:     // string-value   = ( <"> plain-string <"> ) / plain-string
michael@0:     // plain-string   = 1*( %x20-21 / %x23-5B / %x5D-7E )
michael@0:     // We add quotes around the id string, so input identifier must be a plain-string.
michael@0:     if (identifier == null) {
michael@0:       throw new IllegalArgumentException("identifier must not be null.");
michael@0:     }
michael@0:     if (!isPlainString(identifier)) {
michael@0:       throw new IllegalArgumentException("identifier must be a plain-string.");
michael@0:     }
michael@0: 
michael@0:     if (key == null) {
michael@0:       throw new IllegalArgumentException("key must not be null.");
michael@0:     }
michael@0: 
michael@0:     this.identifier = identifier;
michael@0:     this.key = key;
michael@0:   }
michael@0: 
michael@0:   @Override
michael@0:   public Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client) throws GeneralSecurityException {
michael@0:     long timestamp = System.currentTimeMillis() / 1000;
michael@0:     String nonce = Base64.encodeBase64String(Utils.generateRandomBytes(NONCE_LENGTH_IN_BYTES));
michael@0:     String extra = "";
michael@0: 
michael@0:     try {
michael@0:       return getAuthHeader(request, context, client, timestamp, nonce, extra);
michael@0:     } catch (InvalidKeyException e) {
michael@0:       // We lie a little and make every exception a GeneralSecurityException.
michael@0:       throw new GeneralSecurityException(e);
michael@0:     } catch (UnsupportedEncodingException e) {
michael@0:       throw new GeneralSecurityException(e);
michael@0:     } catch (NoSuchAlgorithmException e) {
michael@0:       throw new GeneralSecurityException(e);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Test if input is a <code>plain-string</code>.
michael@0:    * <p>
michael@0:    * A plain-string is defined by the MAC Authentication spec as
michael@0:    * <code>plain-string   = 1*( %x20-21 / %x23-5B / %x5D-7E )</code>.
michael@0:    *
michael@0:    * @param input
michael@0:    *          as a String of "US-ASCII" bytes.
michael@0:    * @return true if input is a <code>plain-string</code>; false otherwise.
michael@0:    * @throws UnsupportedEncodingException
michael@0:    */
michael@0:   protected static boolean isPlainString(String input) {
michael@0:     if (input == null || input.length() == 0) {
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     byte[] bytes;
michael@0:     try {
michael@0:       bytes = input.getBytes("US-ASCII");
michael@0:     } catch (UnsupportedEncodingException e) {
michael@0:       // Should never happen.
michael@0:       Logger.warn(LOG_TAG, "Got exception in isPlainString; returning false.", e);
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     for (byte b : bytes) {
michael@0:       if ((0x20 <= b && b <= 0x21) || (0x23 <= b && b <= 0x5B) || (0x5D <= b && b <= 0x7E)) {
michael@0:         continue;
michael@0:       }
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Helper function that generates an HTTP Authorization header given
michael@0:    * additional MAC Authentication specific data.
michael@0:    *
michael@0:    * @throws UnsupportedEncodingException
michael@0:    * @throws NoSuchAlgorithmException 
michael@0:    * @throws InvalidKeyException 
michael@0:    */
michael@0:   protected Header getAuthHeader(HttpRequestBase request, BasicHttpContext context, DefaultHttpClient client,
michael@0:       long timestamp, String nonce, String extra)
michael@0:       throws UnsupportedEncodingException, InvalidKeyException, NoSuchAlgorithmException {
michael@0:     // Validate timestamp.  From the MAC Authentication spec:
michael@0:     // timestamp      = 1*DIGIT
michael@0:     // This is equivalent to timestamp >= 0.
michael@0:     if (timestamp < 0) {
michael@0:       throw new IllegalArgumentException("timestamp must contain only [0-9].");
michael@0:     }
michael@0: 
michael@0:     // Validate nonce string.  From the MAC Authentication spec:
michael@0:     // nonce          = "nonce" "=" string-value
michael@0:     // string-value   = ( <"> plain-string <"> ) / plain-string
michael@0:     // plain-string   = 1*( %x20-21 / %x23-5B / %x5D-7E )
michael@0:     // We add quotes around the nonce string, so input nonce must be a plain-string.
michael@0:     if (nonce == null) {
michael@0:       throw new IllegalArgumentException("nonce must not be null.");
michael@0:     }
michael@0:     if (nonce.length() == 0) {
michael@0:       throw new IllegalArgumentException("nonce must not be empty.");
michael@0:     }
michael@0:     if (!isPlainString(nonce)) {
michael@0:       throw new IllegalArgumentException("nonce must be a plain-string.");
michael@0:     }
michael@0: 
michael@0:     // Validate extra string.  From the MAC Authentication spec:
michael@0:     // ext            = "ext" "=" string-value
michael@0:     // string-value   = ( <"> plain-string <"> ) / plain-string
michael@0:     // plain-string   = 1*( %x20-21 / %x23-5B / %x5D-7E )
michael@0:     // We add quotes around the extra string, so input extra must be a plain-string.
michael@0:     // We break the spec by allowing ext to be an empty string, i.e. to match 0*(...).
michael@0:     if (extra == null) {
michael@0:       throw new IllegalArgumentException("extra must not be null.");
michael@0:     }
michael@0:     if (extra.length() > 0 && !isPlainString(extra)) {
michael@0:       throw new IllegalArgumentException("extra must be a plain-string.");
michael@0:     }
michael@0: 
michael@0:     String requestString = getRequestString(request, timestamp, nonce, extra);
michael@0:     String macString = getSignature(requestString, this.key);
michael@0: 
michael@0:     String h = "MAC id=\"" + this.identifier + "\", " +
michael@0:                "ts=\""     + timestamp       + "\", " +
michael@0:                "nonce=\""  + nonce           + "\", " +
michael@0:                "mac=\""    + macString       + "\"";
michael@0: 
michael@0:     if (extra != null) {
michael@0:       h += ", ext=\"" + extra + "\"";
michael@0:     }
michael@0: 
michael@0:     Header header = new BasicHeader("Authorization", h);
michael@0: 
michael@0:     return header;
michael@0:   }
michael@0: 
michael@0:   protected static byte[] sha1(byte[] message, byte[] key)
michael@0:       throws NoSuchAlgorithmException, InvalidKeyException {
michael@0: 
michael@0:     SecretKeySpec keySpec = new SecretKeySpec(key, HMAC_SHA1_ALGORITHM);
michael@0: 
michael@0:     Mac hasher = Mac.getInstance(HMAC_SHA1_ALGORITHM);
michael@0:     hasher.init(keySpec);
michael@0:     hasher.update(message);
michael@0: 
michael@0:     byte[] hmac = hasher.doFinal();
michael@0: 
michael@0:     return hmac;
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Sign an HMAC request string.
michael@0:    *
michael@0:    * @param requestString to sign.
michael@0:    * @param key as <code>String</code>.
michael@0:    * @return signature as base-64 encoded string.
michael@0:    * @throws InvalidKeyException
michael@0:    * @throws NoSuchAlgorithmException
michael@0:    * @throws UnsupportedEncodingException
michael@0:    */
michael@0:   protected static String getSignature(String requestString, String key)
michael@0:       throws InvalidKeyException, NoSuchAlgorithmException, UnsupportedEncodingException {
michael@0:     String macString = Base64.encodeBase64String(sha1(requestString.getBytes("UTF-8"), key.getBytes("UTF-8")));
michael@0: 
michael@0:     return macString;
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Generate an HMAC request string.
michael@0:    * <p>
michael@0:    * This method trusts its inputs to be valid as per the MAC Authentication spec.
michael@0:    *
michael@0:    * @param request HTTP request.
michael@0:    * @param timestamp to use.
michael@0:    * @param nonce to use.
michael@0:    * @param extra to use.
michael@0:    * @return request string.
michael@0:    */
michael@0:   protected static String getRequestString(HttpUriRequest request, long timestamp, String nonce, String extra) {
michael@0:     String method = request.getMethod().toUpperCase();
michael@0: 
michael@0:     URI uri = request.getURI();
michael@0:     String host = uri.getHost();
michael@0: 
michael@0:     String path = uri.getRawPath();
michael@0:     if (uri.getRawQuery() != null) {
michael@0:       path += "?";
michael@0:       path += uri.getRawQuery();
michael@0:     }
michael@0:     if (uri.getRawFragment() != null) {
michael@0:       path += "#";
michael@0:       path += uri.getRawFragment();
michael@0:     }
michael@0: 
michael@0:     int port = uri.getPort();
michael@0:     String scheme = uri.getScheme();
michael@0:     if (port != -1) {
michael@0:     } else if ("http".equalsIgnoreCase(scheme)) {
michael@0:       port = 80;
michael@0:     } else if ("https".equalsIgnoreCase(scheme)) {
michael@0:       port = 443;
michael@0:     } else {
michael@0:       throw new IllegalArgumentException("Unsupported URI scheme: " + scheme + ".");
michael@0:     }
michael@0: 
michael@0:     String requestString = timestamp + "\n" +
michael@0:         nonce       + "\n" +
michael@0:         method      + "\n" +
michael@0:         path        + "\n" +
michael@0:         host        + "\n" +
michael@0:         port        + "\n" +
michael@0:         extra       + "\n";
michael@0: 
michael@0:     return requestString;
michael@0:   }
michael@0: }