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// Copyright 2017 Google LLC
//
// 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 com.google.crypto.tink.signature;
import com.google.crypto.tink.Key;
import com.google.crypto.tink.PublicKeyVerify;
import com.google.crypto.tink.internal.KeysetHandleInterface;
import com.google.crypto.tink.internal.LegacyProtoKey;
import com.google.crypto.tink.internal.MonitoringClient;
import com.google.crypto.tink.internal.MonitoringUtil;
import com.google.crypto.tink.internal.MutableMonitoringRegistry;
import com.google.crypto.tink.internal.MutablePrimitiveRegistry;
import com.google.crypto.tink.internal.PrefixMap;
import com.google.crypto.tink.internal.PrimitiveConstructor;
import com.google.crypto.tink.internal.PrimitiveRegistry;
import com.google.crypto.tink.internal.PrimitiveSet;
import com.google.crypto.tink.internal.PrimitiveWrapper;
import com.google.crypto.tink.signature.internal.LegacyFullVerify;
import com.google.crypto.tink.util.Bytes;
import java.security.GeneralSecurityException;
/**
* The implementation of {@code PrimitiveWrapper}.
*
* The returned primitive works with a keyset (rather than a single key). To verify a signature,
* the primitive uses the prefix of the signature to efficiently select the right key in the set. If
* there is no key associated with the prefix or if the keys associated with the prefix do not work,
* the primitive tries all keys with {@link com.google.crypto.tink.proto.OutputPrefixType#RAW}.
*
* @since 1.0.0
*/
public class PublicKeyVerifyWrapper implements PrimitiveWrapper {
private static class PublicKeyVerifyWithId {
public PublicKeyVerifyWithId(PublicKeyVerify publicKeyVerify, int id) {
this.publicKeyVerify = publicKeyVerify;
this.id = id;
}
public final PublicKeyVerify publicKeyVerify;
public final int id;
}
private static final PublicKeyVerifyWrapper WRAPPER = new PublicKeyVerifyWrapper();
private static final PrimitiveConstructor
LEGACY_PRIMITIVE_CONSTRUCTOR =
PrimitiveConstructor.create(
LegacyFullVerify::create, LegacyProtoKey.class, PublicKeyVerify.class);
private static Bytes getOutputPrefix(Key key) throws GeneralSecurityException {
if (key instanceof SignaturePublicKey) {
return ((SignaturePublicKey) key).getOutputPrefix();
}
if (key instanceof LegacyProtoKey) {
return ((LegacyProtoKey) key).getOutputPrefix();
}
throw new GeneralSecurityException(
"Cannot get output prefix for key of class "
+ key.getClass().getName()
+ " with parameters "
+ key.getParameters());
}
private static class WrappedPublicKeyVerify implements PublicKeyVerify {
private final PrefixMap allPublicKeyVerifys;
private final MonitoringClient.Logger monitoringLogger;
public WrappedPublicKeyVerify(
PrefixMap allPublicKeyVerifys,
MonitoringClient.Logger monitoringLogger) {
this.allPublicKeyVerifys = allPublicKeyVerifys;
this.monitoringLogger = monitoringLogger;
}
@Override
public void verify(final byte[] signature, final byte[] data) throws GeneralSecurityException {
for (PublicKeyVerifyWithId publicKeyVerifyWithId :
allPublicKeyVerifys.getAllWithMatchingPrefix(signature)) {
try {
publicKeyVerifyWithId.publicKeyVerify.verify(signature, data);
monitoringLogger.log(publicKeyVerifyWithId.id, data.length);
// If there is no exception, the signature is valid and we can return.
return;
} catch (GeneralSecurityException e) {
// Ignored
}
}
monitoringLogger.logFailure();
throw new GeneralSecurityException("invalid signature");
}
}
@Override
public PublicKeyVerify wrap(final PrimitiveSet primitives)
throws GeneralSecurityException {
PrefixMap.Builder builder = new PrefixMap.Builder<>();
KeysetHandleInterface keysetHandle = primitives.getKeysetHandle();
for (int i = 0; i < keysetHandle.size(); i++) {
KeysetHandleInterface.Entry entry = keysetHandle.getAt(i);
PublicKeyVerify publicKeyVerify = primitives.getPrimitiveForEntry(entry);
builder.put(
getOutputPrefix(entry.getKey()),
new PublicKeyVerifyWithId(publicKeyVerify, entry.getId()));
}
MonitoringClient.Logger logger;
if (!primitives.getAnnotations().isEmpty()) {
MonitoringClient client = MutableMonitoringRegistry.globalInstance().getMonitoringClient();
logger =
client.createLogger(
keysetHandle, primitives.getAnnotations(), "public_key_verify", "verify");
} else {
logger = MonitoringUtil.DO_NOTHING_LOGGER;
}
return new WrappedPublicKeyVerify(builder.build(), logger);
}
@Override
public Class getPrimitiveClass() {
return PublicKeyVerify.class;
}
@Override
public Class getInputPrimitiveClass() {
return PublicKeyVerify.class;
}
/**
* Register the wrapper within the registry.
*
* This is required for calls to {@link Keyset.getPrimitive} with a {@link PublicKeyVerify}
* argument.
*/
static void register() throws GeneralSecurityException {
MutablePrimitiveRegistry.globalInstance().registerPrimitiveWrapper(WRAPPER);
MutablePrimitiveRegistry.globalInstance()
.registerPrimitiveConstructor(LEGACY_PRIMITIVE_CONSTRUCTOR);
}
/**
* registerToInternalPrimitiveRegistry is a non-public method (it takes an argument of an
* internal-only type) registering an instance of {@code PublicKeyVerifyWrapper} to the provided
* {@code PrimitiveRegistry#Builder}.
*/
public static void registerToInternalPrimitiveRegistry(
PrimitiveRegistry.Builder primitiveRegistryBuilder) throws GeneralSecurityException {
primitiveRegistryBuilder.registerPrimitiveWrapper(WRAPPER);
}
}