mech-ntlm.c revision f968e62caa52a8924bd05ebf76ff515b5c18e17b
/*
* NTLM and NTLMv2 authentication mechanism.
*
* Copyright (c) 2004 Andrey Panin <pazke@donpac.ru>
*
* This software is released under the MIT license.
*/
#include "common.h"
#include "mech.h"
#include "passdb.h"
#include "str.h"
#include "buffer.h"
#include "hex-binary.h"
#include "safe-memset.h"
#include "ntlm.h"
struct ntlm_auth_request {
struct auth_request auth_request;
pool_t pool;
/* requested: */
bool ntlm2_negotiated;
bool unicode_negotiated;
const unsigned char *challenge;
/* received: */
struct ntlmssp_response *response;
};
static int lm_verify_credentials(struct ntlm_auth_request *request,
const char *credentials)
{
const unsigned char *client_response;
unsigned char lm_response[LM_RESPONSE_SIZE];
unsigned char hash[LM_HASH_SIZE];
unsigned int response_length;
buffer_t *hash_buffer;
response_length =
ntlmssp_buffer_length(request->response, lm_response);
client_response = ntlmssp_buffer_data(request->response, lm_response);
if (response_length < LM_RESPONSE_SIZE) {
auth_request_log_error(&request->auth_request, "ntlm",
"LM response length is too small");
return FALSE;
}
hash_buffer = buffer_create_data(request->auth_request.pool,
hash, sizeof(hash));
if (hex_to_binary(credentials, hash_buffer) < 0) {
auth_request_log_error(&request->auth_request, "ntlm",
"passdb credentials are not in hex");
return FALSE;
}
ntlmssp_v1_response(hash, request->challenge, lm_response);
return memcmp(lm_response, client_response, LM_RESPONSE_SIZE) == 0;
}
static void
lm_credentials_callback(enum passdb_result result,
const char *credentials,
struct auth_request *auth_request)
{
struct ntlm_auth_request *request =
(struct ntlm_auth_request *)auth_request;
switch (result) {
case PASSDB_RESULT_OK:
if (lm_verify_credentials(request, credentials))
auth_request_success(auth_request, NULL, 0);
else
auth_request_fail(auth_request);
break;
case PASSDB_RESULT_INTERNAL_FAILURE:
auth_request_internal_failure(auth_request);
break;
default:
auth_request_fail(auth_request);
break;
}
}
static int ntlm_verify_credentials(struct ntlm_auth_request *request,
const char *credentials)
{
struct auth_request *auth_request = &request->auth_request;
const unsigned char *client_response;
unsigned char hash[NTLMSSP_HASH_SIZE];
unsigned int response_length;
buffer_t *hash_buffer;
response_length =
ntlmssp_buffer_length(request->response, ntlm_response);
client_response = ntlmssp_buffer_data(request->response, ntlm_response);
if (response_length == 0) {
/* try LM authentication unless NTLM2 was negotiated */
return request->ntlm2_negotiated ? -1 : 0;
}
hash_buffer = buffer_create_data(auth_request->pool,
hash, sizeof(hash));
if (hex_to_binary(credentials, hash_buffer) < 0) {
auth_request_log_error(&request->auth_request, "ntlm",
"passdb credentials are not in hex");
return 0;
}
if (response_length > NTLMSSP_RESPONSE_SIZE) {
unsigned char ntlm_v2_response[NTLMSSP_V2_RESPONSE_SIZE];
const unsigned char *blob =
client_response + NTLMSSP_V2_RESPONSE_SIZE;
/*
* Authentication target == NULL because we are acting
* as a standalone server, not as NT domain member.
*/
ntlmssp_v2_response(auth_request->user, NULL,
hash, request->challenge, blob,
response_length - NTLMSSP_V2_RESPONSE_SIZE,
ntlm_v2_response);
return memcmp(ntlm_v2_response, client_response,
NTLMSSP_V2_RESPONSE_SIZE) == 0 ? 1 : -1;
} else {
unsigned char ntlm_response[NTLMSSP_RESPONSE_SIZE];
const unsigned char *client_lm_response =
ntlmssp_buffer_data(request->response, lm_response);
if (request->ntlm2_negotiated)
ntlmssp2_response(hash, request->challenge,
client_lm_response,
ntlm_response);
else
ntlmssp_v1_response(hash, request->challenge,
ntlm_response);
return memcmp(ntlm_response, client_response,
NTLMSSP_RESPONSE_SIZE) == 0 ? 1 : -1;
}
}
static void
ntlm_credentials_callback(enum passdb_result result,
const char *credentials,
struct auth_request *auth_request)
{
struct ntlm_auth_request *request =
(struct ntlm_auth_request *)auth_request;
int ret;
switch (result) {
case PASSDB_RESULT_OK:
ret = ntlm_verify_credentials(request, credentials);
if (ret > 0) {
auth_request_success(auth_request, NULL, 0);
return;
}
if (ret < 0) {
auth_request_fail(auth_request);
return;
}
break;
case PASSDB_RESULT_INTERNAL_FAILURE:
auth_request_internal_failure(auth_request);
return;
default:
break;
}
/* NTLM credentials not found or didn't want to use them,
try with LM credentials */
auth_request_lookup_credentials(auth_request, PASSDB_CREDENTIALS_LANMAN,
lm_credentials_callback);
}
static void
mech_ntlm_auth_continue(struct auth_request *auth_request,
const unsigned char *data, size_t data_size)
{
struct ntlm_auth_request *request =
(struct ntlm_auth_request *)auth_request;
const char *error;
if (!request->challenge) {
const struct ntlmssp_request *ntlm_request =
(const struct ntlmssp_request *)data;
const struct ntlmssp_challenge *message;
size_t message_size;
uint32_t flags;
if (!ntlmssp_check_request(ntlm_request, data_size, &error)) {
auth_request_log_info(auth_request, "ntlm",
"invalid NTLM request: %s", error);
auth_request_fail(auth_request);
return;
}
message = ntlmssp_create_challenge(request->pool, ntlm_request,
&message_size);
flags = read_le32(&message->flags);
request->ntlm2_negotiated = flags & NTLMSSP_NEGOTIATE_NTLM2;
request->unicode_negotiated = flags & NTLMSSP_NEGOTIATE_UNICODE;
request->challenge = message->challenge;
auth_request->callback(auth_request,
AUTH_CLIENT_RESULT_CONTINUE,
message, message_size);
} else {
const struct ntlmssp_response *response =
(const struct ntlmssp_response *)data;
const char *username;
if (!ntlmssp_check_response(response, data_size, &error)) {
auth_request_log_info(auth_request, "ntlm",
"invalid NTLM response: %s", error);
auth_request_fail(auth_request);
return;
}
request->response = p_malloc(request->pool, data_size);
memcpy(request->response, response, data_size);
username = ntlmssp_t_str(request->response, user,
request->unicode_negotiated);
if (!auth_request_set_username(auth_request, username, &error)) {
auth_request_log_info(auth_request, "ntlm",
"%s", error);
auth_request_fail(auth_request);
return;
}
auth_request_lookup_credentials(auth_request,
PASSDB_CREDENTIALS_NTLM,
ntlm_credentials_callback);
}
}
static struct auth_request *mech_ntlm_auth_new(void)
{
struct ntlm_auth_request *request;
pool_t pool;
pool = pool_alloconly_create("ntlm_auth_request", 1024);
request = p_new(pool, struct ntlm_auth_request, 1);
request->pool = pool;
request->auth_request.pool = pool;
return &request->auth_request;
}
const struct mech_module mech_ntlm = {
"NTLM",
MEMBER(flags) MECH_SEC_DICTIONARY | MECH_SEC_ACTIVE,
MEMBER(passdb_need_plain) FALSE,
MEMBER(passdb_need_credentials) TRUE,
MEMBER(passdb_need_set_credentials) FALSE,
mech_ntlm_auth_new,
mech_generic_auth_initial,
mech_ntlm_auth_continue,
mech_generic_auth_free
};