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WebServer.java
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WebServer.java
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/*
* Copyright The Cryostat Authors.
*
* Licensed 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 io.cryostat.agent;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.time.Duration;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import java.util.zip.DeflaterOutputStream;
import io.cryostat.agent.remote.RemoteContext;
import com.sun.net.httpserver.BasicAuthenticator;
import com.sun.net.httpserver.Filter;
import com.sun.net.httpserver.HttpContext;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpServer;
import dagger.Lazy;
import org.apache.http.HttpStatus;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
class WebServer {
private final Logger log = LoggerFactory.getLogger(getClass());
private final Lazy<Set<RemoteContext>> remoteContexts;
private final Lazy<CryostatClient> cryostat;
private final ScheduledExecutorService executor;
private final String host;
private final int port;
private final Credentials credentials;
private final URI callback;
private final Lazy<Registration> registration;
private final int registrationRetryMs;
private HttpServer http;
private volatile int credentialId = -1;
private final AgentAuthenticator agentAuthenticator;
private final RequestLoggingFilter requestLoggingFilter;
private final CompressionFilter compressionFilter;
WebServer(
Lazy<Set<RemoteContext>> remoteContexts,
Lazy<CryostatClient> cryostat,
ScheduledExecutorService executor,
String host,
int port,
URI callback,
Lazy<Registration> registration,
int registrationRetryMs) {
this.remoteContexts = remoteContexts;
this.cryostat = cryostat;
this.executor = executor;
this.host = host;
this.port = port;
this.credentials = new Credentials();
this.callback = callback;
this.registration = registration;
this.registrationRetryMs = registrationRetryMs;
this.agentAuthenticator = new AgentAuthenticator();
this.requestLoggingFilter = new RequestLoggingFilter();
this.compressionFilter = new CompressionFilter();
}
void start() throws IOException, NoSuchAlgorithmException {
if (this.http != null) {
stop();
}
this.http = HttpServer.create(new InetSocketAddress(host, port), 0);
this.http.setExecutor(executor);
Set<RemoteContext> mergedContexts = new HashSet<>(remoteContexts.get());
mergedContexts.add(new PingContext());
mergedContexts.forEach(
rc -> {
HttpContext ctx = this.http.createContext(rc.path(), rc::handle);
ctx.setAuthenticator(agentAuthenticator);
ctx.getFilters().add(requestLoggingFilter);
ctx.getFilters().add(compressionFilter);
});
this.http.start();
}
void stop() {
if (this.http != null) {
this.http.stop(0);
this.http = null;
}
}
int getCredentialId() {
return credentialId;
}
CompletableFuture<Void> generateCredentials() throws NoSuchAlgorithmException {
synchronized (this.credentials) {
this.credentials.regenerate();
return this.cryostat
.get()
.submitCredentialsIfRequired(this.credentialId, this.credentials, this.callback)
.handle(
(v, t) -> {
if (t != null) {
log.error("Could not submit credentials", t);
executor.schedule(
() -> {
try {
this.generateCredentials();
} catch (NoSuchAlgorithmException e) {
log.error("Cannot submit credentials", e);
}
},
registrationRetryMs,
TimeUnit.MILLISECONDS);
}
return v;
})
.thenAccept(
i -> {
this.credentialId = i;
log.info("Defined credentials with id {}", i);
})
.thenRun(this.credentials::clear);
}
}
private class PingContext implements RemoteContext {
@Override
public String path() {
return "/";
}
@Override
public void handle(HttpExchange exchange) throws IOException {
String mtd = exchange.getRequestMethod();
switch (mtd) {
case "POST":
synchronized (WebServer.this.credentials) {
executor.execute(registration.get()::tryRegister);
exchange.sendResponseHeaders(HttpStatus.SC_NO_CONTENT, -1);
exchange.close();
}
break;
case "GET":
exchange.sendResponseHeaders(HttpStatus.SC_NO_CONTENT, -1);
exchange.close();
break;
default:
exchange.sendResponseHeaders(HttpStatus.SC_NOT_FOUND, -1);
exchange.close();
break;
}
}
}
private class RequestLoggingFilter extends Filter {
@Override
public void doFilter(HttpExchange exchange, Chain chain) throws IOException {
long start = System.nanoTime();
String requestMethod = exchange.getRequestMethod();
String path = exchange.getRequestURI().getPath();
log.info("{} {}", requestMethod, path);
chain.doFilter(exchange);
long elapsed = System.nanoTime() - start;
log.info(
"{} {} : {} {}ms",
requestMethod,
path,
exchange.getResponseCode(),
Duration.ofNanos(elapsed).toMillis());
}
@Override
public String description() {
return "requestLog";
}
}
private class CompressionFilter extends Filter {
@Override
public void doFilter(HttpExchange exchange, Chain chain) throws IOException {
List<String> requestedEncodings =
exchange.getRequestHeaders().getOrDefault("Accept-Encoding", List.of()).stream()
.map(raw -> raw.replaceAll("\\s", ""))
.map(raw -> raw.split(","))
.map(Arrays::asList)
.flatMap(List::stream)
.collect(Collectors.toList());
String negotiatedEncoding = null;
priority:
for (String encoding : requestedEncodings) {
switch (encoding) {
case "deflate":
negotiatedEncoding = encoding;
exchange.setStreams(
exchange.getRequestBody(),
new DeflaterOutputStream(exchange.getResponseBody()));
break priority;
// TODO gzip encoding breaks communication with the server, need to
// determine why and re-enable this
// case "gzip":
// actualEncoding = requestedEncoding;
// exchange.setStreams(
// exchange.getRequestBody(),
// new GZIPOutputStream(exchange.getResponseBody()));
// break priority;
default:
break;
}
}
if (negotiatedEncoding == null) {
log.info("Using no encoding");
} else {
log.info("Using '{}' encoding", negotiatedEncoding);
exchange.getResponseHeaders().put("Content-Encoding", List.of(negotiatedEncoding));
}
chain.doFilter(exchange);
}
@Override
public String description() {
return "responseCompression";
}
}
private class AgentAuthenticator extends BasicAuthenticator {
private final Logger log = LoggerFactory.getLogger(getClass());
public AgentAuthenticator() {
super("cryostat-agent");
}
@Override
public boolean checkCredentials(String username, String password) {
try {
return WebServer.this.credentials.checkUserInfo(username, password);
} catch (NoSuchAlgorithmException e) {
log.error("Could not check credentials", e);
return false;
}
}
}
static class Credentials {
private static final String user = "agent";
private final SecureRandom random = new SecureRandom();
private byte[] passHash = new byte[0];
private byte[] pass = new byte[0];
synchronized boolean checkUserInfo(String username, String password)
throws NoSuchAlgorithmException {
return passHash.length > 0
&& Objects.equals(username, Credentials.user)
&& Arrays.equals(hash(password), this.passHash);
}
synchronized void regenerate() throws NoSuchAlgorithmException {
this.clear();
final int len = 24;
this.pass = new byte[len];
// guarantee at least one character from each class
this.pass[0] = randomSymbol();
this.pass[1] = randomNumeric();
this.pass[2] = randomAlphabetical(random.nextBoolean());
// fill remaining slots with randomly assigned characters across classes
for (int i = 3; i < len; i++) {
int s = random.nextInt(3);
if (s == 0) {
this.pass[i] = randomSymbol();
} else if (s == 1) {
this.pass[i] = randomNumeric();
} else {
this.pass[i] = randomAlphabetical(random.nextBoolean());
}
}
// randomly shuffle the characters
// https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle
for (int i = this.pass.length - 1; i > 1; i--) {
int j = random.nextInt(i);
byte b = this.pass[i];
this.pass[i] = this.pass[j];
this.pass[j] = b;
}
this.passHash = hash(this.pass);
}
String user() {
return user;
}
synchronized byte[] pass() {
return pass;
}
synchronized void clear() {
Arrays.fill(this.pass, (byte) 0);
}
private byte randomAlphabetical(boolean upperCase) throws NoSuchAlgorithmException {
return randomChar(upperCase ? 'A' : 'a', 26);
}
private byte randomNumeric() throws NoSuchAlgorithmException {
return randomChar('0', 10);
}
private byte randomSymbol() throws NoSuchAlgorithmException {
return randomChar(33, 14);
}
private byte randomChar(int offset, int range) throws NoSuchAlgorithmException {
return (byte) (random.nextInt(range) + offset);
}
private static byte[] hash(String pass) throws NoSuchAlgorithmException {
return hash(pass.getBytes(StandardCharsets.UTF_8));
}
private static byte[] hash(byte[] bytes) throws NoSuchAlgorithmException {
return MessageDigest.getInstance("SHA-256").digest(bytes);
}
}
}