From fe789088c181e8545bd0af9de12d497fa179dc05 Mon Sep 17 00:00:00 2001 From: Lari Hotari Date: Sat, 30 Apr 2022 23:04:30 +0300 Subject: [PATCH] [Proxy/Client] Fix DNS server denial-of-service issue when DNS entry expires (#15403) - DnsNameResolver doesn't coordinate concurrency and this leads to DNS server DoS under high load - In Netty, DnsAddressResolverGroup internally uses internal InflightNameResolver class to address the problem - The solution is to use DnsAddressResolverGroup instead of instantiating DnsNameResolver directly --- .../client/impl/ConnectionPoolTest.java | 38 ++++++------- .../pulsar/client/impl/ConnectionPool.java | 54 +++++++++---------- .../pulsar/proxy/server/ProxyConnection.java | 11 ++-- .../pulsar/proxy/server/ProxyService.java | 12 ++--- .../server/ServiceChannelInitializer.java | 2 +- 5 files changed, 60 insertions(+), 57 deletions(-) diff --git a/pulsar-broker/src/test/java/org/apache/pulsar/client/impl/ConnectionPoolTest.java b/pulsar-broker/src/test/java/org/apache/pulsar/client/impl/ConnectionPoolTest.java index a375eb852cb2b..9ba703ce494eb 100644 --- a/pulsar-broker/src/test/java/org/apache/pulsar/client/impl/ConnectionPoolTest.java +++ b/pulsar-broker/src/test/java/org/apache/pulsar/client/impl/ConnectionPoolTest.java @@ -21,6 +21,10 @@ import com.google.common.collect.Lists; import io.netty.channel.EventLoopGroup; import io.netty.util.concurrent.DefaultThreadFactory; +import java.net.InetSocketAddress; +import java.util.List; +import java.util.concurrent.CompletableFuture; +import java.util.stream.IntStream; import org.apache.pulsar.broker.auth.MockedPulsarServiceBaseTest; import org.apache.pulsar.client.impl.conf.ClientConfigurationData; import org.apache.pulsar.common.util.netty.EventLoopUtil; @@ -30,21 +34,17 @@ import org.testng.annotations.BeforeClass; import org.testng.annotations.Test; -import java.net.InetAddress; -import java.net.InetSocketAddress; -import java.util.List; -import java.util.concurrent.CompletableFuture; -import java.util.stream.IntStream; - public class ConnectionPoolTest extends MockedPulsarServiceBaseTest { String serviceUrl; + int brokerPort; @BeforeClass @Override protected void setup() throws Exception { super.internalSetup(); - serviceUrl = "pulsar://non-existing-dns-name:" + pulsar.getBrokerListenPort().get(); + brokerPort = pulsar.getBrokerListenPort().get(); + serviceUrl = "pulsar://non-existing-dns-name:" + brokerPort; } @AfterClass(alwaysRun = true) @@ -61,9 +61,11 @@ public void testSingleIpAddress() throws Exception { conf.setServiceUrl(serviceUrl); PulsarClientImpl client = new PulsarClientImpl(conf, eventLoop, pool); - List result = Lists.newArrayList(); - result.add(InetAddress.getByName("127.0.0.1")); - Mockito.when(pool.resolveName("non-existing-dns-name")).thenReturn(CompletableFuture.completedFuture(result)); + List result = Lists.newArrayList(); + result.add(new InetSocketAddress("127.0.0.1", brokerPort)); + Mockito.when(pool.resolveName(InetSocketAddress.createUnresolved("non-existing-dns-name", + brokerPort))) + .thenReturn(CompletableFuture.completedFuture(result)); client.newProducer().topic("persistent://sample/standalone/ns/my-topic").create(); @@ -73,20 +75,20 @@ public void testSingleIpAddress() throws Exception { @Test public void testDoubleIpAddress() throws Exception { - String serviceUrl = "pulsar://non-existing-dns-name:" + pulsar.getBrokerListenPort().get(); - ClientConfigurationData conf = new ClientConfigurationData(); EventLoopGroup eventLoop = EventLoopUtil.newEventLoopGroup(1, new DefaultThreadFactory("test")); ConnectionPool pool = Mockito.spy(new ConnectionPool(conf, eventLoop)); conf.setServiceUrl(serviceUrl); PulsarClientImpl client = new PulsarClientImpl(conf, eventLoop, pool); - List result = Lists.newArrayList(); + List result = Lists.newArrayList(); // Add a non existent IP to the response to check that we're trying the 2nd address as well - result.add(InetAddress.getByName("127.0.0.99")); - result.add(InetAddress.getByName("127.0.0.1")); - Mockito.when(pool.resolveName("non-existing-dns-name")).thenReturn(CompletableFuture.completedFuture(result)); + result.add(new InetSocketAddress("127.0.0.99", brokerPort)); + result.add(new InetSocketAddress("127.0.0.1", brokerPort)); + Mockito.when(pool.resolveName(InetSocketAddress.createUnresolved("non-existing-dns-name", + brokerPort))) + .thenReturn(CompletableFuture.completedFuture(result)); // Create producer should succeed by trying the 2nd IP client.newProducer().topic("persistent://sample/standalone/ns/my-topic").create(); @@ -103,7 +105,7 @@ public void testNoConnectionPool() throws Exception { ConnectionPool pool = Mockito.spy(new ConnectionPool(conf, eventLoop)); InetSocketAddress brokerAddress = - InetSocketAddress.createUnresolved("127.0.0.1", pulsar.getBrokerListenPort().get()); + InetSocketAddress.createUnresolved("127.0.0.1", brokerPort); IntStream.range(1, 5).forEach(i -> { pool.getConnection(brokerAddress).thenAccept(cnx -> { Assert.assertTrue(cnx.channel().isActive()); @@ -125,7 +127,7 @@ public void testEnableConnectionPool() throws Exception { ConnectionPool pool = Mockito.spy(new ConnectionPool(conf, eventLoop)); InetSocketAddress brokerAddress = - InetSocketAddress.createUnresolved("127.0.0.1", pulsar.getBrokerListenPort().get()); + InetSocketAddress.createUnresolved("127.0.0.1", brokerPort); IntStream.range(1, 10).forEach(i -> { pool.getConnection(brokerAddress).thenAccept(cnx -> { Assert.assertTrue(cnx.channel().isActive()); diff --git a/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConnectionPool.java b/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConnectionPool.java index 99492784e5fb1..8d09ee6776b34 100644 --- a/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConnectionPool.java +++ b/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConnectionPool.java @@ -25,10 +25,10 @@ import io.netty.channel.ChannelException; import io.netty.channel.ChannelOption; import io.netty.channel.EventLoopGroup; -import io.netty.resolver.dns.DnsNameResolver; +import io.netty.resolver.AddressResolver; +import io.netty.resolver.dns.DnsAddressResolverGroup; import io.netty.resolver.dns.DnsNameResolverBuilder; import io.netty.util.concurrent.Future; -import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.URI; import java.net.URISyntaxException; @@ -62,7 +62,7 @@ public class ConnectionPool implements AutoCloseable { private final int maxConnectionsPerHosts; private final boolean isSniProxy; - protected final DnsNameResolver dnsResolver; + protected final AddressResolver addressResolver; private final boolean shouldCloseDnsResolver; public ConnectionPool(ClientConfigurationData conf, EventLoopGroup eventLoopGroup) throws PulsarClientException { @@ -75,7 +75,8 @@ public ConnectionPool(ClientConfigurationData conf, EventLoopGroup eventLoopGrou } public ConnectionPool(ClientConfigurationData conf, EventLoopGroup eventLoopGroup, - Supplier clientCnxSupplier, Optional dnsNameResolver) + Supplier clientCnxSupplier, + Optional> addressResolver) throws PulsarClientException { this.eventLoopGroup = eventLoopGroup; this.clientConfig = conf; @@ -100,15 +101,19 @@ public ConnectionPool(ClientConfigurationData conf, EventLoopGroup eventLoopGrou throw new PulsarClientException(e); } - this.shouldCloseDnsResolver = !dnsNameResolver.isPresent(); - this.dnsResolver = dnsNameResolver.orElseGet(() -> createDnsNameResolver(conf, eventLoopGroup)); + this.shouldCloseDnsResolver = !addressResolver.isPresent(); + this.addressResolver = addressResolver.orElseGet(() -> createAddressResolver(conf, eventLoopGroup)); } - private static DnsNameResolver createDnsNameResolver(ClientConfigurationData conf, EventLoopGroup eventLoopGroup) { - DnsNameResolverBuilder dnsNameResolverBuilder = new DnsNameResolverBuilder(eventLoopGroup.next()) + private static AddressResolver createAddressResolver(ClientConfigurationData conf, + EventLoopGroup eventLoopGroup) { + DnsNameResolverBuilder dnsNameResolverBuilder = new DnsNameResolverBuilder() .traceEnabled(true).channelType(EventLoopUtil.getDatagramChannelClass(eventLoopGroup)); DnsResolverUtil.applyJdkDnsCacheSettings(dnsNameResolverBuilder); - return dnsNameResolverBuilder.build(); + // use DnsAddressResolverGroup to create the AddressResolver since it contains a solution + // to prevent cache stampede / thundering herds problem when a DNS entry expires while the system + // is under high load + return new DnsAddressResolverGroup(dnsNameResolverBuilder).getResolver(eventLoopGroup.next()); } private static final Random random = new Random(); @@ -235,19 +240,17 @@ private CompletableFuture createConnection(InetSocketAddress logicalA * Resolve DNS asynchronously and attempt to connect to any IP address returned by DNS server. */ private CompletableFuture createConnection(InetSocketAddress unresolvedAddress) { - int port; - CompletableFuture> resolvedAddress = null; + CompletableFuture> resolvedAddress; try { if (isSniProxy) { URI proxyURI = new URI(clientConfig.getProxyServiceUrl()); - port = proxyURI.getPort(); - resolvedAddress = resolveName(proxyURI.getHost()); + resolvedAddress = + resolveName(InetSocketAddress.createUnresolved(proxyURI.getHost(), proxyURI.getPort())); } else { - port = unresolvedAddress.getPort(); - resolvedAddress = resolveName(unresolvedAddress.getHostString()); + resolvedAddress = resolveName(unresolvedAddress); } return resolvedAddress.thenCompose( - inetAddresses -> connectToResolvedAddresses(inetAddresses.iterator(), port, + inetAddresses -> connectToResolvedAddresses(inetAddresses.iterator(), isSniProxy ? unresolvedAddress : null)); } catch (URISyntaxException e) { log.error("Invalid Proxy url {}", clientConfig.getProxyServiceUrl(), e); @@ -260,18 +263,17 @@ private CompletableFuture createConnection(InetSocketAddress unresolved * Try to connect to a sequence of IP addresses until a successful connection can be made, or fail if no * address is working. */ - private CompletableFuture connectToResolvedAddresses(Iterator unresolvedAddresses, - int port, + private CompletableFuture connectToResolvedAddresses(Iterator unresolvedAddresses, InetSocketAddress sniHost) { CompletableFuture future = new CompletableFuture<>(); // Successfully connected to server - connectToAddress(unresolvedAddresses.next(), port, sniHost) + connectToAddress(unresolvedAddresses.next(), sniHost) .thenAccept(future::complete) .exceptionally(exception -> { if (unresolvedAddresses.hasNext()) { // Try next IP address - connectToResolvedAddresses(unresolvedAddresses, port, sniHost).thenAccept(future::complete) + connectToResolvedAddresses(unresolvedAddresses, sniHost).thenAccept(future::complete) .exceptionally(ex -> { // This is already unwinding the recursive call future.completeExceptionally(ex); @@ -287,10 +289,9 @@ private CompletableFuture connectToResolvedAddresses(Iterator> resolveName(String hostname) { - CompletableFuture> future = new CompletableFuture<>(); - dnsResolver.resolveAll(hostname).addListener((Future> resolveFuture) -> { + CompletableFuture> resolveName(InetSocketAddress unresolvedAddress) { + CompletableFuture> future = new CompletableFuture<>(); + addressResolver.resolveAll(unresolvedAddress).addListener((Future> resolveFuture) -> { if (resolveFuture.isSuccess()) { future.complete(resolveFuture.get()); } else { @@ -303,8 +304,7 @@ CompletableFuture> resolveName(String hostname) { /** * Attempt to establish a TCP connection to an already resolved single IP address. */ - private CompletableFuture connectToAddress(InetAddress ipAddress, int port, InetSocketAddress sniHost) { - InetSocketAddress remoteAddress = new InetSocketAddress(ipAddress, port); + private CompletableFuture connectToAddress(InetSocketAddress remoteAddress, InetSocketAddress sniHost) { if (clientConfig.isUseTls()) { return toCompletableFuture(bootstrap.register()) .thenCompose(channel -> channelInitializerHandler @@ -331,7 +331,7 @@ public void releaseConnection(ClientCnx cnx) { public void close() throws Exception { closeAllConnections(); if (shouldCloseDnsResolver) { - dnsResolver.close(); + addressResolver.close(); } } diff --git a/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ProxyConnection.java b/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ProxyConnection.java index fbf604866b8f9..b7b6e359a1159 100644 --- a/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ProxyConnection.java +++ b/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ProxyConnection.java @@ -22,7 +22,7 @@ import static com.google.common.base.Preconditions.checkState; import io.netty.channel.ChannelFutureListener; import io.netty.handler.codec.haproxy.HAProxyMessage; -import io.netty.resolver.dns.DnsNameResolver; +import io.netty.resolver.dns.DnsAddressResolverGroup; import java.net.InetSocketAddress; import java.net.SocketAddress; import java.util.Collections; @@ -82,7 +82,7 @@ public class ProxyConnection extends PulsarHandler { private final AtomicLong requestIdGenerator = new AtomicLong(ThreadLocalRandom.current().nextLong(0, Long.MAX_VALUE / 2)); private final ProxyService service; - private final DnsNameResolver dnsNameResolver; + private final DnsAddressResolverGroup dnsAddressResolverGroup; private Authentication clientAuthentication; AuthenticationDataSource authenticationData; private State state; @@ -134,10 +134,10 @@ ConnectionPool getConnectionPool() { } public ProxyConnection(ProxyService proxyService, Supplier sslHandlerSupplier, - DnsNameResolver dnsNameResolver) { + DnsAddressResolverGroup dnsAddressResolverGroup) { super(30, TimeUnit.SECONDS); this.service = proxyService; - this.dnsNameResolver = dnsNameResolver; + this.dnsAddressResolverGroup = dnsAddressResolverGroup; this.state = State.Init; this.sslHandlerSupplier = sslHandlerSupplier; this.brokerProxyValidator = service.getBrokerProxyValidator(); @@ -280,7 +280,8 @@ private synchronized void completeConnect(AuthData clientData) throws PulsarClie if (this.connectionPool == null) { this.connectionPool = new ConnectionPool(clientConf, service.getWorkerGroup(), - clientCnxSupplier, Optional.of(dnsNameResolver)); + clientCnxSupplier, + Optional.of(dnsAddressResolverGroup.getResolver(service.getWorkerGroup().next()))); } else { LOG.error("BUG! Connection Pool has already been created for proxy connection to {} state {} role {}", remoteAddress, state, clientAuthRole); diff --git a/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ProxyService.java b/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ProxyService.java index 61feb4918ee43..f32c006902f59 100644 --- a/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ProxyService.java +++ b/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ProxyService.java @@ -26,7 +26,7 @@ import io.netty.channel.Channel; import io.netty.channel.ChannelOption; import io.netty.channel.EventLoopGroup; -import io.netty.resolver.dns.DnsNameResolver; +import io.netty.resolver.dns.DnsAddressResolverGroup; import io.netty.resolver.dns.DnsNameResolverBuilder; import io.netty.util.concurrent.DefaultThreadFactory; import io.prometheus.client.Counter; @@ -71,7 +71,7 @@ public class ProxyService implements Closeable { private final ProxyConfiguration proxyConfig; @Getter - private final DnsNameResolver dnsNameResolver; + private final DnsAddressResolverGroup dnsAddressResolverGroup; @Getter private final BrokerProxyValidator brokerProxyValidator; private String serviceUrl; @@ -146,13 +146,13 @@ public ProxyService(ProxyConfiguration proxyConfig, workersThreadFactory); this.authenticationService = authenticationService; - DnsNameResolverBuilder dnsNameResolverBuilder = new DnsNameResolverBuilder(workerGroup.next()) + DnsNameResolverBuilder dnsNameResolverBuilder = new DnsNameResolverBuilder() .channelType(EventLoopUtil.getDatagramChannelClass(workerGroup)); DnsResolverUtil.applyJdkDnsCacheSettings(dnsNameResolverBuilder); - dnsNameResolver = dnsNameResolverBuilder.build(); + dnsAddressResolverGroup = new DnsAddressResolverGroup(dnsNameResolverBuilder); - brokerProxyValidator = new BrokerProxyValidator(dnsNameResolver.asAddressResolver(), + brokerProxyValidator = new BrokerProxyValidator(dnsAddressResolverGroup.getResolver(workerGroup.next()), proxyConfig.getBrokerProxyAllowedHostNames(), proxyConfig.getBrokerProxyAllowedIPAddresses(), proxyConfig.getBrokerProxyAllowedTargetPorts()); @@ -238,7 +238,7 @@ public BrokerDiscoveryProvider getDiscoveryProvider() { } public void close() throws IOException { - dnsNameResolver.close(); + dnsAddressResolverGroup.close(); if (discoveryProvider != null) { discoveryProvider.close(); diff --git a/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ServiceChannelInitializer.java b/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ServiceChannelInitializer.java index 4aae1196fb694..a8f2287ffeaf2 100644 --- a/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ServiceChannelInitializer.java +++ b/pulsar-proxy/src/main/java/org/apache/pulsar/proxy/server/ServiceChannelInitializer.java @@ -159,7 +159,7 @@ public SslHandler get() { } ch.pipeline().addLast("handler", - new ProxyConnection(proxyService, sslHandlerSupplier, proxyService.getDnsNameResolver())); + new ProxyConnection(proxyService, sslHandlerSupplier, proxyService.getDnsAddressResolverGroup())); } }