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// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.node.admin.maintenance.identity;
import com.yahoo.vespa.athenz.api.AthenzService;
import com.yahoo.vespa.athenz.client.zts.DefaultZtsClient;
import com.yahoo.vespa.athenz.client.zts.InstanceIdentity;
import com.yahoo.vespa.athenz.client.zts.ZtsClient;
import com.yahoo.vespa.athenz.client.zts.ZtsClientException;
import com.yahoo.vespa.athenz.identity.ServiceIdentityProvider;
import com.yahoo.vespa.athenz.identityprovider.api.EntityBindingsMapper;
import com.yahoo.vespa.athenz.identityprovider.api.IdentityDocumentClient;
import com.yahoo.vespa.athenz.identityprovider.api.SignedIdentityDocument;
import com.yahoo.vespa.athenz.identityprovider.client.DefaultIdentityDocumentClient;
import com.yahoo.vespa.athenz.identityprovider.client.InstanceCsrGenerator;
import com.yahoo.vespa.athenz.tls.AthenzIdentityVerifier;
import com.yahoo.vespa.athenz.utils.SiaUtils;
import com.yahoo.vespa.hosted.dockerapi.ContainerName;
import com.yahoo.vespa.hosted.node.admin.component.Environment;
import com.yahoo.vespa.hosted.node.admin.util.PrefixLogger;
import javax.net.ssl.SSLContext;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.net.URI;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.security.KeyPair;
import java.security.PrivateKey;
import java.security.cert.X509Certificate;
import java.time.Clock;
import java.time.Duration;
import java.time.Instant;
import static java.util.Collections.singleton;
/**
* A maintainer that is responsible for providing and refreshing Athenz credentials for a container.
*
* @author bjorncs
*/
@SuppressWarnings("deprecation")
public class AthenzCredentialsMaintainer {
private static final Duration EXPIRY_MARGIN = Duration.ofDays(1);
private static final Duration REFRESH_PERIOD = Duration.ofDays(1);
private static final Duration REFRESH_BACKOFF = Duration.ofHours(1); // Backoff when refresh fails to ensure ZTS is not DDoS'ed.
private static final Path CONTAINER_SIA_DIRECTORY = Paths.get("/var/lib/sia");
private final boolean enabled;
private final PrefixLogger log;
private final String hostname;
private final Path trustStorePath;
private final Path privateKeyFile;
private final Path certificateFile;
private final Path identityDocumentFile;
private final AthenzService containerIdentity;
private final URI ztsEndpoint;
private final Clock clock;
private final ServiceIdentityProvider hostIdentityProvider;
private final IdentityDocumentClient identityDocumentClient;
private final InstanceCsrGenerator csrGenerator;
private final AthenzService configserverIdentity;
private Instant lastRefreshAttempt = Instant.EPOCH; // Used as an optimization to ensure ZTS is not DDoS'ed on continuously failing refresh attempts
public AthenzCredentialsMaintainer(String hostname,
Environment environment,
ServiceIdentityProvider hostIdentityProvider) {
ContainerName containerName = ContainerName.fromHostname(hostname);
Path containerSiaDirectory = environment.pathInNodeAdminFromPathInNode(containerName, CONTAINER_SIA_DIRECTORY);
this.enabled = environment.isNodeAgentCertEnabled();
this.log = PrefixLogger.getNodeAgentLogger(AthenzCredentialsMaintainer.class, containerName);
this.hostname = hostname;
this.containerIdentity = environment.getNodeAthenzIdentity();
this.ztsEndpoint = environment.getZtsUri();
this.configserverIdentity = environment.getConfigserverAthenzIdentity();
this.csrGenerator = new InstanceCsrGenerator(environment.getCertificateDnsSuffix());
this.trustStorePath = environment.getTrustStorePath();
this.privateKeyFile = SiaUtils.getPrivateKeyFile(containerSiaDirectory, containerIdentity);
this.certificateFile = SiaUtils.getCertificateFile(containerSiaDirectory, containerIdentity);
this.identityDocumentFile = containerSiaDirectory.resolve("vespa-node-identity-document.json");
this.hostIdentityProvider = hostIdentityProvider;
this.identityDocumentClient =
new DefaultIdentityDocumentClient(
environment.getConfigserverLoadBalancerEndpoint(),
hostIdentityProvider,
new AthenzIdentityVerifier(singleton(configserverIdentity)));
this.clock = Clock.systemUTC();
}
public void converge() {
try {
if (!enabled) {
log.debug("Feature disabled on this host - not fetching certificate");
return;
}
log.debug("Checking certificate");
Instant now = clock.instant();
if (!Files.exists(privateKeyFile) || !Files.exists(certificateFile) || !Files.exists(identityDocumentFile)) {
log.info("Certificate/private key/identity document file does not exist");
Files.createDirectories(privateKeyFile.getParent());
Files.createDirectories(certificateFile.getParent());
Files.createDirectories(identityDocumentFile.getParent());
registerIdentity();
return;
}
X509Certificate certificate = readCertificateFromFile();
Instant expiry = certificate.getNotAfter().toInstant();
if (isCertificateExpired(expiry, now)) {
log.info(String.format("Certificate has expired (expiry=%s)", expiry.toString()));
registerIdentity();
return;
}
Duration age = Duration.between(certificate.getNotBefore().toInstant(), now);
if (shouldRefreshCredentials(age)) {
log.info(String.format("Certificate is ready to be refreshed (age=%s)", age.toString()));
if (shouldThrottleRefreshAttempts(now)) {
log.warning(String.format("Skipping refresh attempt as last refresh was on %s (less than %s ago)",
lastRefreshAttempt.toString(), REFRESH_BACKOFF.toString()));
return;
} else {
lastRefreshAttempt = now;
refreshIdentity();
return;
}
}
log.debug("Certificate is still valid");
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
public void clearCredentials() {
if (!enabled) return;
try {
if (Files.deleteIfExists(privateKeyFile))
log.info(String.format("Deleted private key file (path=%s)", privateKeyFile));
if (Files.deleteIfExists(certificateFile))
log.info(String.format("Deleted certificate file (path=%s)", certificateFile));
if (Files.deleteIfExists(identityDocumentFile))
log.info(String.format("Deleted identity document file (path=%s)", certificateFile));
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
private boolean shouldRefreshCredentials(Duration age) {
return age.compareTo(REFRESH_PERIOD) >= 0;
}
private boolean shouldThrottleRefreshAttempts(Instant now) {
return REFRESH_BACKOFF.compareTo(Duration.between(lastRefreshAttempt, now)) > 0;
}
private X509Certificate readCertificateFromFile() throws IOException {
String pemEncodedCertificate = new String(Files.readAllBytes(certificateFile));
return com.yahoo.vespa.athenz.tls.X509CertificateUtils.fromPem(pemEncodedCertificate);
}
private boolean isCertificateExpired(Instant expiry, Instant now) {
return now.isAfter(expiry.minus(EXPIRY_MARGIN));
}
private void registerIdentity() {
KeyPair keyPair = com.yahoo.vespa.athenz.tls.KeyUtils.generateKeypair(com.yahoo.vespa.athenz.tls.KeyAlgorithm.RSA);
SignedIdentityDocument signedIdentityDocument = identityDocumentClient.getNodeIdentityDocument(hostname);
com.yahoo.vespa.athenz.tls.Pkcs10Csr csr = csrGenerator.generateCsr(
containerIdentity, signedIdentityDocument.providerUniqueId(), signedIdentityDocument.ipAddresses(), keyPair);
try (ZtsClient ztsClient = new DefaultZtsClient(ztsEndpoint, hostIdentityProvider)) {
InstanceIdentity instanceIdentity =
ztsClient.registerInstance(
configserverIdentity,
containerIdentity,
signedIdentityDocument.providerUniqueId().asDottedString(),
EntityBindingsMapper.toAttestationData(signedIdentityDocument),
false,
csr);
EntityBindingsMapper.writeSignedIdentityDocumentToFile(identityDocumentFile, signedIdentityDocument);
writePrivateKeyAndCertificate(keyPair.getPrivate(), instanceIdentity.certificate());
log.info("Instance successfully registered and credentials written to file");
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
private void refreshIdentity() {
SignedIdentityDocument identityDocument = EntityBindingsMapper.readSignedIdentityDocumentFromFile(identityDocumentFile);
KeyPair keyPair = com.yahoo.vespa.athenz.tls.KeyUtils.generateKeypair(com.yahoo.vespa.athenz.tls.KeyAlgorithm.RSA);
com.yahoo.vespa.athenz.tls.Pkcs10Csr csr = csrGenerator.generateCsr(containerIdentity, identityDocument.providerUniqueId(), identityDocument.ipAddresses(), keyPair);
SSLContext containerIdentitySslContext =
new com.yahoo.vespa.athenz.tls.SslContextBuilder()
.withKeyStore(privateKeyFile.toFile(), certificateFile.toFile())
.withTrustStore(trustStorePath.toFile(), com.yahoo.vespa.athenz.tls.KeyStoreType.JKS)
.build();
try {
try (ZtsClient ztsClient = new DefaultZtsClient(ztsEndpoint, containerIdentity, containerIdentitySslContext)) {
InstanceIdentity instanceIdentity =
ztsClient.refreshInstance(
configserverIdentity,
containerIdentity,
identityDocument.providerUniqueId().asDottedString(),
false,
csr);
writePrivateKeyAndCertificate(keyPair.getPrivate(), instanceIdentity.certificate());
log.info("Instance successfully refreshed and credentials written to file");
} catch (ZtsClientException e) {
if (e.getErrorCode() == 403 && e.getDescription().startsWith("Certificate revoked")) {
log.error("Certificate cannot be refreshed as it is revoked by ZTS - re-registering the instance now", e);
registerIdentity();
} else {
throw e;
}
}
} catch (Exception e) {
log.error("Certificate refresh failed: " + e.getMessage(), e);
}
}
private void writePrivateKeyAndCertificate(PrivateKey privateKey, X509Certificate certificate) throws IOException {
Path tempPrivateKeyFile = toTempPath(privateKeyFile);
Files.write(tempPrivateKeyFile, com.yahoo.vespa.athenz.tls.KeyUtils.toPem(privateKey).getBytes());
Path tempCertificateFile = toTempPath(certificateFile);
Files.write(tempCertificateFile, com.yahoo.vespa.athenz.tls.X509CertificateUtils.toPem(certificate).getBytes());
Files.move(tempPrivateKeyFile, privateKeyFile, StandardCopyOption.ATOMIC_MOVE);
Files.move(tempCertificateFile, certificateFile, StandardCopyOption.ATOMIC_MOVE);
}
private static Path toTempPath(Path file) {
return Paths.get(file.toAbsolutePath().toString() + ".tmp");
}
}
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