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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Based on [MS-NLMP]: NT LAN Manager (NTLM) Authentication Protocol
// Specification version 28.0 [1], an unofficial NTLM reference [2], and a
// blog post describing Extended Protection for Authentication [3].
//
// [1] https://msdn.microsoft.com/en-us/library/cc236621.aspx
// [2] http://davenport.sourceforge.net/ntlm.html
// [3]
// https://blogs.msdn.microsoft.com/openspecification/2013/03/26/ntlm-and-channel-binding-hash-aka-extended-protection-for-authentication/
#ifndef NET_NTLM_NTLM_CLIENT_H_
#define NET_NTLM_NTLM_CLIENT_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <string>
#include "base/check.h"
#include "base/containers/span.h"
#include "base/strings/string_piece.h"
#include "net/base/net_export.h"
#include "net/ntlm/ntlm_constants.h"
namespace net::ntlm {
// Provides an implementation of an NTLMv1 or NTLMv2 Client with support
// for MIC and EPA [1]. This implementation does not support the key exchange,
// signing or sealing feature as the NTLMSSP_NEGOTIATE_KEY_EXCH flag is never
// negotiated.
//
// [1] -
// https://support.microsoft.com/en-us/help/968389/extended-protection-for-authentication
class NET_EXPORT_PRIVATE NtlmClient {
public:
// Pass feature flags to enable/disable NTLMv2 and additional NTLMv2
// features such as Extended Protection for Authentication (EPA) and Message
// Integrity Check (MIC).
explicit NtlmClient(NtlmFeatures features);
NtlmClient(const NtlmClient&) = delete;
NtlmClient& operator=(const NtlmClient&) = delete;
~NtlmClient();
bool IsNtlmV2() const { return features_.enable_NTLMv2; }
bool IsMicEnabled() const { return IsNtlmV2() && features_.enable_MIC; }
bool IsEpaEnabled() const { return IsNtlmV2() && features_.enable_EPA; }
// Returns the Negotiate message.
std::vector<uint8_t> GetNegotiateMessage() const;
// Returns a the Authenticate message. If the method fails an empty vector
// is returned.
//
// |username| is treated case insensitively by NTLM however the mechanism
// to uppercase is not clearly defined. In this implementation the default
// locale is used. Additionally for names longer than 20 characters, the
// fully qualified name in the new '@' format must be used.
// eg. very_long_name@domain.com. Names shorter than 20 characters can
// optionally omit the '@domain.com' part.
// |hostname| can be a short NetBIOS name or an FQDN, however the server will
// only inspect this field if the default domain policy is to restrict NTLM.
// In this case the hostname will be compared to an allowlist stored in this
// group policy [1].
// |channel_bindings| is a string supplied out of band (usually from a web
// browser) and is a (21+sizeof(hash)) byte ASCII string, where 'hash' is
// usually a SHA-256 of the servers certificate, but may be another hash
// algorithm. The format as defined by RFC 5929 Section 4 is shown below;
//
// [0-20] - "tls-server-end-point:" (Literal string)
// [21-(20+sizeof(hash)] - HASH(server_certificate) (Certificate hash)
//
// |spn| is a string supplied out of band (usually from a web browser) and
// is a Service Principal Name [2]. For NTLM over HTTP the value of this
// string will usually be "HTTP/<hostname>".
// |client_time| 64 bit Windows timestamp defined as the number of
// 100 nanosecond ticks since midnight Jan 01, 1601 (UTC). If the server does
// not send a timestamp, the client timestamp is used in the Proof Input
// instead.
// |server_challenge_message| is the full content of the challenge message
// sent by the server.
//
// [1] - https://technet.microsoft.com/en-us/library/jj852267(v=ws.11).aspx
std::vector<uint8_t> GenerateAuthenticateMessage(
const std::u16string& domain,
const std::u16string& username,
const std::u16string& password,
const std::string& hostname,
const std::string& channel_bindings,
const std::string& spn,
uint64_t client_time,
base::span<const uint8_t, kChallengeLen> client_challenge,
base::span<const uint8_t> server_challenge_message) const;
// Simplified method for NTLMv1 which does not require |channel_bindings|,
// |spn|, or |client_time|. See |GenerateAuthenticateMessage| for more
// details.
std::vector<uint8_t> GenerateAuthenticateMessageV1(
const std::u16string& domain,
const std::u16string& username,
const std::u16string& password,
const std::string& hostname,
base::span<const uint8_t, 8> client_challenge,
base::span<const uint8_t> server_challenge_message) const {
DCHECK(!IsNtlmV2());
return GenerateAuthenticateMessage(
domain, username, password, hostname, std::string(), std::string(), 0,
client_challenge, server_challenge_message);
}
private:
// Returns the length of the Authenticate message based on the length of the
// variable length parts of the message and whether Unicode support was
// negotiated.
size_t CalculateAuthenticateMessageLength(
bool is_unicode,
const std::u16string& domain,
const std::u16string& username,
const std::string& hostname,
size_t updated_target_info_len) const;
bool CalculatePayloadLayout(bool is_unicode,
const std::u16string& domain,
const std::u16string& username,
const std::string& hostname,
size_t updated_target_info_len,
SecurityBuffer* lm_info,
SecurityBuffer* ntlm_info,
SecurityBuffer* domain_info,
SecurityBuffer* username_info,
SecurityBuffer* hostname_info,
SecurityBuffer* session_key_info,
size_t* authenticate_message_len) const;
// Returns the length of the header part of the Authenticate message.
size_t GetAuthenticateHeaderLength() const;
// Returns the length of the NTLM response.
size_t GetNtlmResponseLength(size_t updated_target_info_len) const;
// Generates the negotiate message (which is always the same) into
// |negotiate_message_|.
void GenerateNegotiateMessage();
const NtlmFeatures features_;
NegotiateFlags negotiate_flags_;
std::vector<uint8_t> negotiate_message_;
};
} // namespace net::ntlm
#endif // NET_NTLM_NTLM_CLIENT_H_