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/*
* Copyright (C) 2014 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/client/sasl_scramsha1_client_conversation.h"
#include <boost/algorithm/string/replace.hpp>
#include <boost/scoped_ptr.hpp>
#include "mongo/base/parse_number.h"
#include "mongo/client/sasl_client_session.h"
#include "mongo/platform/random.h"
#include "mongo/util/base64.h"
#include "mongo/util/mongoutils/str.h"
#include "mongo/util/password_digest.h"
#include "mongo/util/text.h"
namespace mongo {
using boost::scoped_ptr;
using std::string;
SaslSCRAMSHA1ClientConversation::SaslSCRAMSHA1ClientConversation(
SaslClientSession* saslClientSession) :
SaslClientConversation(saslClientSession),
_step(0),
_authMessage(""),
_clientNonce("") {
}
SaslSCRAMSHA1ClientConversation::~SaslSCRAMSHA1ClientConversation(){
// clear the _saltedPassword memory
memset(_saltedPassword, 0, scram::hashSize);
}
StatusWith<bool> SaslSCRAMSHA1ClientConversation::step(StringData inputData,
std::string* outputData) {
std::vector<std::string> input = StringSplitter::split(inputData.toString(), ",");
_step++;
switch (_step) {
case 1:
return _firstStep(outputData);
case 2:
// Append server-first-message to _authMessage
_authMessage += inputData.toString() + ",";
return _secondStep(input, outputData);
case 3:
return _thirdStep(input, outputData);
default:
return StatusWith<bool>(ErrorCodes::AuthenticationFailed,
mongoutils::str::stream() <<
"Invalid SCRAM-SHA-1 authentication step: " << _step);
}
}
/*
* RFC 5802 specifies that in SCRAM user names characters ',' and '=' are encoded as
* =2C and =3D respectively.
*/
static void encodeSCRAMUsername(std::string& user) {
boost::replace_all(user, "=", "=3D");
boost::replace_all(user, ",", "=2C");
}
/*
* Generate client-first-message of the form:
* n,a=authzid,n=encoded-username,r=client-nonce
*/
StatusWith<bool> SaslSCRAMSHA1ClientConversation::_firstStep(std::string* outputData) {
if (_saslClientSession->getParameter(SaslClientSession::parameterPassword).empty()) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Empty client password provided");
}
// Create text-based nonce as base64 encoding of a binary blob of length multiple of 3
const int nonceLenQWords = 3;
uint64_t binaryNonce[nonceLenQWords];
scoped_ptr<SecureRandom> sr(SecureRandom::create());
binaryNonce[0] = sr->nextInt64();
binaryNonce[1] = sr->nextInt64();
binaryNonce[2] = sr->nextInt64();
std::string user =
_saslClientSession->getParameter(SaslClientSession::parameterUser).toString();
encodeSCRAMUsername(user);
std::string clientNonce = base64::encode(reinterpret_cast<char*>(binaryNonce),
sizeof(binaryNonce));
// Append client-first-message-bare to authMessage
_authMessage = "n=" + user + ",r=" + clientNonce + ",";
StringBuilder sb;
sb << "n,,n=" << user <<
",r=" << clientNonce;
*outputData = sb.str();
return StatusWith<bool>(false);
}
/**
* Parse server-first-message on the form:
* r=client-nonce|server-nonce,s=user-salt,i=iteration-count
*
* Generate client-final-message of the form:
* c=channel-binding(base64),r=client-nonce|server-nonce,p=ClientProof
*
**/
StatusWith<bool> SaslSCRAMSHA1ClientConversation::_secondStep(const std::vector<string>& input,
std::string* outputData) {
if (input.size() != 3) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Incorrect number of arguments for first SCRAM-SHA-1 server message, got " <<
input.size() << " expected 3");
}
else if (!str::startsWith(input[0], "r=") || input[0].size() < 2) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Incorrect SCRAM-SHA-1 client|server nonce: " << input[0]);
}
else if (!str::startsWith(input[1], "s=") || input[1].size() < 6) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Incorrect SCRAM-SHA-1 salt: " << input[1]);
}
else if(!str::startsWith(input[2], "i=") || input[2].size() < 3) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Incorrect SCRAM-SHA-1 iteration count: " << input[2]);
}
std::string nonce = input[0].substr(2);
if(!str::startsWith(nonce, _clientNonce)) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Server SCRAM-SHA-1 nonce does not match client nonce" << input[2]);
}
std::string salt = input[1].substr(2);
int iterationCount;
Status status = parseNumberFromStringWithBase(input[2].substr(2), 10, &iterationCount);
if (status != Status::OK()) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Failed to parse SCRAM-SHA-1 iteration count: " << input[2]);
}
// Append client-final-message-without-proof to _authMessage
_authMessage += "c=biws,r=" + nonce;
std::string decodedSalt;
try {
decodedSalt = base64::decode(salt);
}
catch (const DBException& ex) {
return StatusWith<bool>(ex.toStatus());
}
scram::generateSaltedPassword(
_saslClientSession->getParameter(SaslClientSession::parameterPassword),
reinterpret_cast<const unsigned char*>(decodedSalt.c_str()),
decodedSalt.size(),
iterationCount,
_saltedPassword);
std::string clientProof = scram::generateClientProof(_saltedPassword, _authMessage);
StringBuilder sb;
sb << "c=biws,r=" << nonce << ",p=" << clientProof;
*outputData = sb.str();
return StatusWith<bool>(false);
}
/**
* Verify server-final-message on the form:
* v=ServerSignature
*
* or failed authentication server-final-message on the form:
* e=message
**/
StatusWith<bool> SaslSCRAMSHA1ClientConversation::_thirdStep(const std::vector<string>& input,
std::string* outputData) {
if (input.size() != 1) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Incorrect number of arguments for final SCRAM-SHA-1 server message, got " <<
input.size() << " expected 1");
}
else if (input[0].size() < 3) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Incorrect SCRAM-SHA-1 server message length: " << input[0]);
}
else if (str::startsWith(input[0], "e=")) {
return StatusWith<bool>(ErrorCodes::AuthenticationFailed, mongoutils::str::stream() <<
"SCRAM-SHA-1 authentication failure: " << input[0].substr(2));
}
else if (!str::startsWith(input[0], "v=")) {
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Incorrect SCRAM-SHA-1 ServerSignature: " << input[0]);
}
bool validServerSignature =
scram::verifyServerSignature(_saltedPassword, _authMessage, input[0].substr(2));
if (!validServerSignature) {
*outputData = "e=Invalid server signature";
return StatusWith<bool>(ErrorCodes::BadValue, mongoutils::str::stream() <<
"Client failed to verify SCRAM-SHA-1 ServerSignature, received " <<
input[0].substr(2));
}
*outputData = "";
return StatusWith<bool>(true);
}
} // namespace mongo
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