Java tutorial
/** * PublicKeyRegistrationService * Copyright 29.06.2015 by Robert Mader, @treba13 * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program in the file lgpl21.txt * If not, see <http://www.gnu.org/licenses/>. */ package org.loklak.api.aaa; import org.bouncycastle.util.io.pem.PemObject; import org.bouncycastle.util.io.pem.PemReader; import org.bouncycastle.util.io.pem.PemWriter; import org.eclipse.jetty.util.log.Log; import org.json.JSONArray; import org.json.JSONObject; import org.loklak.data.DAO; import org.loklak.server.*; import org.loklak.tools.IO; import org.loklak.tools.storage.JSONObjectWithDefault; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.StringReader; import java.io.StringWriter; import java.io.UnsupportedEncodingException; import java.net.URLDecoder; import java.net.URLEncoder; import java.security.*; import java.security.interfaces.RSAPublicKey; import java.security.spec.X509EncodedKeySpec; import java.util.Base64; import java.util.stream.IntStream; /** * This service allows users to register a public key for login. * It can either take a public key or create a new key-pair. * Users can also be granted the right to register keys for individual other users or whole user roles. * * To export your own PublikKey from java for registering, call: * - String encodedPublicKey = Base64.getEncoder().encodeToString(publicKey.getEncoded()); * * To use the private key as generated in DER format in java, call: * - PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.getDecoder().decode(encodedPrivateKey)); * - PrivateKey privateKey = KeyFactory.getInstance("RSA").generatePrivate(keySpec); * * To sign a challenge as given by the login, call: * - Signature sig = Signature.getInstance("SHA256withRSA"); * - sig.initSign(privateKey); * - sig.update(challengeString.getBytes()); * - String result = new String(Base64.getEncoder().encode(sig.sign())); * * To create a signature with openssl (using a key in pem format), the following command should work: * - openssl dgst -sha256 -sign privkey.pem -out response.txt challenge.txt * - encode the content of response.in BASE64 * - if necessary, encode it URL-friendly */ public class PublicKeyRegistrationService extends AbstractAPIHandler implements APIHandler { private static final long serialVersionUID = 8578478303032749879L; private static final int[] allowedKeySizesRSA = { 1024, 2048, 4096 }; private static final int defaultKeySizeRSA = 2048; private static final String[] allowedFormats = { "DER", "PEM" }; @Override public BaseUserRole getMinimalBaseUserRole() { return BaseUserRole.ANONYMOUS; } @Override public JSONObject getDefaultPermissions(BaseUserRole baseUserRole) { JSONObject result = new JSONObject(); switch (baseUserRole) { case ADMIN: result.put("self", true); result.put("users", new JSONObject()); JSONObject userRoles = new JSONObject(); for (String userRole : DAO.userRoles.getUserRoles().keySet()) { userRoles.put(userRole, true); } result.put("userRoles", userRoles); break; case PRIVILEGED: case USER: result.put("self", true); result.put("users", new JSONObject()); result.put("userRoles", new JSONObject()); break; case ANONYMOUS: default: result.put("self", false); result.put("users", new JSONObject()); result.put("userRoles", new JSONObject()); } return result; } public String getAPIPath() { return "/aaa/pubkey_registration.json"; } @Override public JSONObject serviceImpl(Query post, HttpServletResponse response, Authorization authorization, final JSONObjectWithDefault permissions) throws APIException { if (post.get("register", null) == null && !post.get("create", false) && !post.get("getParameters", false)) { throw new APIException(400, "Accepted parameters: 'register', 'create' or 'getParameters'"); } JSONObject result = new JSONObject(); // return algorithm parameters and users for whom we are allowed to register a key if (post.get("getParameters", false)) { result.put("self", permissions.getBoolean("self", false)); result.put("users", permissions.getJSONObject("users")); result.put("userRoles", permissions.getJSONObject("userRoles")); JSONObject algorithms = new JSONObject(); JSONObject rsa = new JSONObject(); JSONArray keySizes = new JSONArray(); for (int i : allowedKeySizesRSA) { keySizes.put(i); } rsa.put("sizes", keySizes); rsa.put("defaultSize", defaultKeySizeRSA); algorithms.put("RSA", rsa); result.put("algorithms", algorithms); JSONArray formats = new JSONArray(); for (String format : allowedFormats) { formats.put(format); } result.put("formats", formats); return result; } // for which id? String id; if (post.get("id", null) != null) id = post.get("id", null); else id = authorization.getIdentity().getName(); // check if we are allowed register a key if (!id.equals(authorization.getIdentity().getName())) { // if we don't want to register the key for the current user // create Authentication to check if the user id is a registered user ClientCredential credential = new ClientCredential(ClientCredential.Type.passwd_login, id); Authentication authentication = new Authentication(credential, DAO.authentication); if (authentication.getIdentity() == null) { // check if identity is valid authentication.delete(); throw new APIException(400, "Bad request"); // do not leak if user exists or not } // check if the current user is allowed to create a key for the user in question boolean allowed = false; // check if the user in question is in 'users' if (permissions.getJSONObject("users", null).has(id) && permissions.getJSONObjectWithDefault("users", null).getBoolean(id, false)) { allowed = true; } else { // check if the user role of the user in question is in 'userRoles' Authorization auth = new Authorization(authentication.getIdentity(), DAO.authorization, DAO.userRoles); for (String key : permissions.getJSONObject("userRoles").keySet()) { if (key.equals(auth.getUserRole().getName()) && permissions.getJSONObject("userRoles").getBoolean(key)) { allowed = true; } } } if (!allowed) throw new APIException(400, "Bad request"); // do not leak if user exists or not } else { // if we want to register a key for this user, bad are not allowed to (for example anonymous users) if (!permissions.getBoolean("self", false)) throw new APIException(403, "You are not allowed to register a public key"); } // set algorithm. later, we maybe want to support other algorithms as well String algorithm = "RSA"; if (post.get("algorithm", null) != null) { algorithm = post.get("algorithm", null); } if (post.get("create", false)) { // create a new key pair on the server if (algorithm.equals("RSA")) { int keySize = 2048; if (post.get("key-size", null) != null) { int finalKeyLength = post.get("key-size", 0); if (!IntStream.of(allowedKeySizesRSA).anyMatch(x -> x == finalKeyLength)) { throw new APIException(400, "Invalid key size."); } keySize = finalKeyLength; } KeyPairGenerator keyGen; KeyPair keyPair; try { keyGen = KeyPairGenerator.getInstance(algorithm); keyGen.initialize(keySize); keyPair = keyGen.genKeyPair(); } catch (NoSuchAlgorithmException e) { throw new APIException(500, "Server error"); } registerKey(authorization.getIdentity(), keyPair.getPublic()); String pubkey_pem = null, privkey_pem = null; try { StringWriter writer = new StringWriter(); PemWriter pemWriter = new PemWriter(writer); pemWriter.writeObject(new PemObject("PUBLIC KEY", keyPair.getPublic().getEncoded())); pemWriter.flush(); pemWriter.close(); pubkey_pem = writer.toString(); } catch (IOException e) { } try { StringWriter writer = new StringWriter(); PemWriter pemWriter = new PemWriter(writer); pemWriter.writeObject(new PemObject("PRIVATE KEY", keyPair.getPrivate().getEncoded())); pemWriter.flush(); pemWriter.close(); privkey_pem = writer.toString(); } catch (IOException e) { } result.put("publickey_DER_BASE64", Base64.getEncoder().encodeToString(keyPair.getPublic().getEncoded())); result.put("privatekey_DER_BASE64", Base64.getEncoder().encodeToString(keyPair.getPrivate().getEncoded())); result.put("publickey_PEM", pubkey_pem); result.put("privatekey_PEM", privkey_pem); result.put("keyhash", IO.getKeyHash(keyPair.getPublic())); try { result.put("keyhash_urlsave", URLEncoder.encode(IO.getKeyHash(keyPair.getPublic()), "UTF-8")); } catch (UnsupportedEncodingException e) { } result.put("key-size", keySize); result.put("message", "Successfully created and registered key. Make sure to copy the private key, it won't be saved on the server"); return result; } throw new APIException(400, "Unsupported algorithm"); } else if (post.get("register", null) != null) { if (algorithm.equals("RSA")) { String type = post.get("type", null); if (type == null) type = "DER"; RSAPublicKey pub; String encodedKey; try { encodedKey = URLDecoder.decode(post.get("register", null), "UTF-8"); } catch (Throwable e) { throw new APIException(500, "Server error"); } Log.getLog().info("Key (" + type + "): " + encodedKey); if (type.equals("DER")) { try { X509EncodedKeySpec keySpec = new X509EncodedKeySpec(Base64.getDecoder().decode(encodedKey)); pub = (RSAPublicKey) KeyFactory.getInstance(algorithm).generatePublic(keySpec); } catch (Throwable e) { throw new APIException(400, "Public key not readable (DER)"); } } else if (type.equals("PEM")) { try { PemReader pemReader = new PemReader(new StringReader(encodedKey)); PemObject pem = pemReader.readPemObject(); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(pem.getContent()); pub = (RSAPublicKey) KeyFactory.getInstance(algorithm).generatePublic(keySpec); } catch (Exception e) { throw new APIException(400, "Public key not readable (PEM)"); } } else { throw new APIException(400, "Invalid value for 'type'."); } // check key size (not really perfect yet) int keySize; int bitLength = pub.getModulus().bitLength(); if (bitLength <= 512) { keySize = 512; } else if (bitLength <= 1024) { keySize = 1024; } else if (bitLength <= 2048) { keySize = 2048; } else if (bitLength <= 4096) { keySize = 4096; } else { keySize = 8192; } if (!IntStream.of(allowedKeySizesRSA).anyMatch(x -> x == keySize)) { throw new APIException(400, "Invalid key length."); } registerKey(authorization.getIdentity(), pub); String pubkey_pem = null; try { StringWriter writer = new StringWriter(); PemWriter pemWriter = new PemWriter(writer); pemWriter.writeObject(new PemObject("PUBLIC KEY", pub.getEncoded())); pemWriter.flush(); pemWriter.close(); pubkey_pem = writer.toString(); } catch (IOException e) { } result.put("publickey_DER_BASE64", Base64.getEncoder().encodeToString(pub.getEncoded())); result.put("publickey_PEM", pubkey_pem); result.put("keyhash", IO.getKeyHash(pub)); try { result.put("keyhash_urlsave", URLEncoder.encode(IO.getKeyHash(pub), "UTF-8")); } catch (UnsupportedEncodingException e) { } result.put("message", "Successfully registered key."); return result; } throw new APIException(400, "Unsupported algorithm"); } throw new APIException(400, "Invalid parameter"); } /** * Registers a key for an identity. * TODO: different algorithms * @param id * @param key */ private void registerKey(ClientIdentity id, PublicKey key) throws APIException { JSONObject user_obj; try { user_obj = DAO.login_keys.getJSONObject(id.toString()); } catch (Throwable e) { user_obj = new JSONObject(); DAO.login_keys.put(id.toString(), user_obj); } if (user_obj.has(IO.getKeyHash(key))) throw new APIException(422, "Key already registered"); user_obj.put(IO.getKeyHash(key), IO.getKeyAsString(key)); DAO.login_keys.commit(); } }