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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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.
*/
#pragma once
#include <string>
#include "mongo/base/secure_allocator.h"
#include "mongo/base/status.h"
#include "mongo/crypto/sha1_block.h"
#include "mongo/db/auth/authorization_manager.h"
#include "mongo/db/jsobj.h"
namespace mongo {
namespace scram {
const std::string serverKeyConst = "Server Key";
const std::string clientKeyConst = "Client Key";
const std::string iterationCountFieldName = "iterationCount";
const std::string saltFieldName = "salt";
const std::string storedKeyFieldName = "storedKey";
const std::string serverKeyFieldName = "serverKey";
/*
* The precursors necessary to perform the computation which produces SCRAMSecrets.
* These are the original password, its salt, and the number of times it must be
* hashed to produce the SaltedPassword used to generate the rest of the SCRAMSecrets.
*/
struct SCRAMPresecrets {
SCRAMPresecrets(std::string hashedPassword,
std::vector<std::uint8_t> salt_,
size_t iterationCount_)
: hashedPassword(std::move(hashedPassword)),
salt(std::move(salt_)),
iterationCount(iterationCount_) {
uassert(ErrorCodes::BadValue,
"Invalid salt for SCRAM mechanism",
salt.size() >= kSaltLengthMin);
}
std::string hashedPassword;
std::vector<std::uint8_t> salt;
size_t iterationCount;
private:
static const size_t kSaltLengthMin = 16;
};
inline bool operator==(const SCRAMPresecrets& lhs, const SCRAMPresecrets& rhs) {
return lhs.hashedPassword == rhs.hashedPassword && lhs.salt == rhs.salt &&
lhs.iterationCount == rhs.iterationCount;
}
/*
* Computes the SaltedPassword from password, salt and iterationCount.
*/
SHA1Block generateSaltedPassword(const SCRAMPresecrets& presecrets);
/*
* Stores all of the keys, generated from a password, needed for a client or server to perform a
* SCRAM handshake.
* These keys are reference counted, and allocated using the SecureAllocator.
* May be unpopulated. SCRAMSecrets created via the default constructor are unpopulated.
* The behavior is undefined if the accessors are called when unpopulated.
*/
class SCRAMSecrets {
private:
struct SCRAMSecretsHolder {
SHA1Block clientKey;
SHA1Block storedKey;
SHA1Block serverKey;
};
public:
// Creates an unpopulated SCRAMSecrets object.
SCRAMSecrets() = default;
// Creates a populated SCRAMSecrets object. First, allocates secure storage, then provides it
// to a callback, which fills the memory.
template <typename T>
explicit SCRAMSecrets(T initializationFun)
: _ptr(std::make_shared<SecureAllocatorAuthDomain::SecureHandle<SCRAMSecretsHolder>>()) {
initializationFun((*this)->clientKey, (*this)->storedKey, (*this)->serverKey);
}
// Returns true if the underlying shared_pointer is populated.
explicit operator bool() const {
return static_cast<bool>(_ptr);
}
const SecureAllocatorAuthDomain::SecureHandle<SCRAMSecretsHolder>& operator*() const& {
invariant(_ptr);
return *_ptr;
}
void operator*() && = delete;
const SecureAllocatorAuthDomain::SecureHandle<SCRAMSecretsHolder>& operator->() const& {
invariant(_ptr);
return *_ptr;
}
void operator->() && = delete;
private:
std::shared_ptr<SecureAllocatorAuthDomain::SecureHandle<SCRAMSecretsHolder>> _ptr;
};
/*
* Computes the SCRAM secrets clientKey, storedKey, and serverKey using the salt 'salt'
* and iteration count 'iterationCount' as defined in RFC5802 (server side).
*/
SCRAMSecrets generateSecrets(const SCRAMPresecrets& presecrets);
/*
* Computes the ClientKey and StoredKey from SaltedPassword (client side).
*/
SCRAMSecrets generateSecrets(const SHA1Block& saltedPassword);
/*
* Generates the user salt and the SCRAM secrets storedKey and serverKey as
* defined in RFC5802 (server side).
*/
BSONObj generateCredentials(const std::string& hashedPassword, int iterationCount);
/*
* Computes the ClientProof from ClientKey, StoredKey, and authMessage (client side).
*/
std::string generateClientProof(const SCRAMSecrets& clientCredentials,
const std::string& authMessage);
/*
* Validates that the provided password 'hashedPassword' generates the serverKey
* 'serverKey' given iteration count 'iterationCount' and salt 'salt'.
*/
bool validatePassword(const std::string& hashedPassword,
int iterationCount,
const std::string& salt,
const std::string& storedKey);
/*
* Verifies ServerSignature (client side).
*/
bool verifyServerSignature(const SCRAMSecrets& clientCredentials,
const std::string& authMessage,
const std::string& serverSignature);
/*
* Verifies ClientProof (server side).
*/
bool verifyClientProof(StringData clientProof, StringData storedKey, StringData authMessage);
} // namespace scram
} // namespace mongo
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