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/* Copyright 2012 10gen Inc.
*
* 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.
*/
/**
* This module implements the client side of SASL authentication in MongoDB, in terms of the Cyrus
* SASL library. See <sasl/sasl.h> and http://cyrusimap.web.cmu.edu/ for relevant documentation.
*
* The primary entry point at runtime is saslClientAuthenticateImpl().
*/
#include <boost/scoped_ptr.hpp>
#include <string>
#include "mongo/base/init.h"
#include "mongo/base/status.h"
#include "mongo/base/string_data.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/client/auth_helpers.h"
#include "mongo/client/sasl_client_authenticate.h"
#include "mongo/client/sasl_client_session.h"
#include "mongo/platform/cstdint.h"
#include "mongo/util/base64.h"
#include "mongo/util/log.h"
#include "mongo/util/mongoutils/str.h"
#include "mongo/util/net/hostandport.h"
namespace mongo {
namespace {
// Default log level on the client for SASL log messages.
const int defaultSaslClientLogLevel = 4;
const char* const saslClientLogFieldName = "clientLogLevel";
int getSaslClientLogLevel(const BSONObj& saslParameters) {
int saslLogLevel = defaultSaslClientLogLevel;
BSONElement saslLogElement = saslParameters[saslClientLogFieldName];
if (saslLogElement.trueValue())
saslLogLevel = 1;
if (saslLogElement.isNumber())
saslLogLevel = saslLogElement.numberInt();
return saslLogLevel;
}
/**
* Gets the password data from "saslParameters" and stores it to "outPassword".
*
* If "digestPassword" indicates that the password needs to be "digested" via
* auth::createPasswordDigest(), this method takes care of that.
* On success, the value of "*outPassword" is always the correct value to set
* as the password on the SaslClientSession.
*
* Returns Status::OK() on success, and ErrorCodes::NoSuchKey if the password data is not
* present in "saslParameters". Other ErrorCodes returned indicate other errors.
*/
Status extractPassword(const BSONObj& saslParameters,
bool digestPassword,
std::string* outPassword) {
std::string rawPassword;
Status status = bsonExtractStringField(saslParameters,
saslCommandPasswordFieldName,
&rawPassword);
if (!status.isOK())
return status;
if (digestPassword) {
std::string user;
status = bsonExtractStringField(saslParameters,
saslCommandUserFieldName,
&user);
if (!status.isOK())
return status;
*outPassword = auth::createPasswordDigest(user, rawPassword);
}
else {
*outPassword = rawPassword;
}
return Status::OK();
}
/**
* Configures "session" to perform the client side of a SASL conversation over connection
* "client".
*
* "saslParameters" is a BSON document providing the necessary configuration information.
*
* Returns Status::OK() on success.
*/
Status configureSession(SaslClientSession* session,
DBClientWithCommands* client,
const std::string& targetDatabase,
const BSONObj& saslParameters) {
std::string mechanism;
Status status = bsonExtractStringField(saslParameters,
saslCommandMechanismFieldName,
&mechanism);
if (!status.isOK())
return status;
session->setParameter(SaslClientSession::parameterMechanism, mechanism);
std::string value;
status = bsonExtractStringFieldWithDefault(saslParameters,
saslCommandServiceNameFieldName,
saslDefaultServiceName,
&value);
if (!status.isOK())
return status;
session->setParameter(SaslClientSession::parameterServiceName, value);
status = bsonExtractStringFieldWithDefault(saslParameters,
saslCommandServiceHostnameFieldName,
HostAndPort(client->getServerAddress()).host(),
&value);
if (!status.isOK())
return status;
session->setParameter(SaslClientSession::parameterServiceHostname, value);
status = bsonExtractStringField(saslParameters,
saslCommandUserFieldName,
&value);
if (!status.isOK())
return status;
session->setParameter(SaslClientSession::parameterUser, value);
bool digestPasswordDefault =
!(targetDatabase == "$external" && mechanism == "PLAIN") &&
!(targetDatabase == "$external" && mechanism == "GSSAPI");
bool digestPassword;
status = bsonExtractBooleanFieldWithDefault(saslParameters,
saslCommandDigestPasswordFieldName,
digestPasswordDefault,
&digestPassword);
if (!status.isOK())
return status;
status = extractPassword(saslParameters, digestPassword, &value);
if (status.isOK()) {
session->setParameter(SaslClientSession::parameterPassword, value);
}
else if (status != ErrorCodes::NoSuchKey) {
return status;
}
return session->initialize();
}
/**
* Driver for the client side of a sasl authentication session, conducted synchronously over
* "client".
*/
Status saslClientAuthenticateImpl(DBClientWithCommands* client, const BSONObj& saslParameters) {
int saslLogLevel = getSaslClientLogLevel(saslParameters);
std::string targetDatabase;
try {
Status status = bsonExtractStringFieldWithDefault(saslParameters,
saslCommandUserSourceFieldName,
saslDefaultDBName,
&targetDatabase);
if (!status.isOK())
return status;
} catch (const DBException& ex) {
return ex.toStatus();
}
SaslClientSession session;
Status status = configureSession(&session, client, targetDatabase, saslParameters);
if (!status.isOK())
return status;
BSONObj saslFirstCommandPrefix = BSON(
saslStartCommandName << 1 <<
saslCommandMechanismFieldName <<
session.getParameter(SaslClientSession::parameterMechanism));
BSONObj saslFollowupCommandPrefix = BSON(saslContinueCommandName << 1);
BSONObj saslCommandPrefix = saslFirstCommandPrefix;
BSONObj inputObj = BSON(saslCommandPayloadFieldName << "");
bool isServerDone = false;
while (!session.isDone()) {
std::string payload;
BSONType type;
status = saslExtractPayload(inputObj, &payload, &type);
if (!status.isOK())
return status;
LOG(saslLogLevel) << "sasl client input: " << base64::encode(payload) << endl;
std::string responsePayload;
status = session.step(payload, &responsePayload);
if (!status.isOK())
return status;
LOG(saslLogLevel) << "sasl client output: " << base64::encode(responsePayload) << endl;
BSONObjBuilder commandBuilder;
commandBuilder.appendElements(saslCommandPrefix);
commandBuilder.appendBinData(saslCommandPayloadFieldName,
int(responsePayload.size()),
BinDataGeneral,
responsePayload.c_str());
BSONElement conversationId = inputObj[saslCommandConversationIdFieldName];
if (!conversationId.eoo())
commandBuilder.append(conversationId);
// Server versions 2.3.2 and earlier may return "ok: 1" with a non-zero "code" field,
// indicating a failure. Subsequent versions should return "ok: 0" on failure with a
// non-zero "code" field to indicate specific failure. In all versions, ok: 1, code: >0
// and ok: 0, code optional, indicate failure.
bool ok = client->runCommand(targetDatabase, commandBuilder.obj(), inputObj);
ErrorCodes::Error code = ErrorCodes::fromInt(
inputObj[saslCommandCodeFieldName].numberInt());
if (!ok || code != ErrorCodes::OK) {
if (code == ErrorCodes::OK)
code = ErrorCodes::UnknownError;
return Status(code, inputObj[saslCommandErrmsgFieldName].str());
}
isServerDone = inputObj[saslCommandDoneFieldName].trueValue();
saslCommandPrefix = saslFollowupCommandPrefix;
}
if (!isServerDone)
return Status(ErrorCodes::ProtocolError, "Client finished before server.");
return Status::OK();
}
MONGO_INITIALIZER(SaslClientAuthenticateFunction)(InitializerContext* context) {
saslClientAuthenticate = saslClientAuthenticateImpl;
return Status::OK();
}
} // namespace
} // namespace mongo
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