/*
* Unix SMB/CIFS implementation.
* Version 3.0
* NTLMSSP Signing routines
* Copyright (C) Andrew Bartlett 2003-2005
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "includes.h"
#define CLI_SIGN "session key to client-to-server signing key magic constant"
#define CLI_SEAL "session key to client-to-server sealing key magic constant"
#define SRV_SIGN "session key to server-to-client signing key magic constant"
#define SRV_SEAL "session key to server-to-client sealing key magic constant"
/**
* Some notes on then NTLM2 code:
*
* NTLM2 is a AEAD system. This means that the data encrypted is not
* all the data that is signed. In DCE-RPC case, the headers of the
* DCE-RPC packets are also signed. This prevents some of the
* fun-and-games one might have by changing them.
*
*/
static void calc_ntlmv2_key(unsigned char subkey[16],
DATA_BLOB session_key,
const char *constant)
{
struct MD5Context ctx3;
MD5Init(&ctx3);
MD5Update(&ctx3, session_key.data, session_key.length);
MD5Update(&ctx3, (const unsigned char *)constant, strlen(constant)+1);
MD5Final(subkey, &ctx3);
}
enum ntlmssp_direction {
NTLMSSP_SEND,
NTLMSSP_RECEIVE
};
static NTSTATUS ntlmssp_make_packet_signature(NTLMSSP_STATE *ntlmssp_state,
const uchar *data, size_t length,
const uchar *whole_pdu, size_t pdu_length,
enum ntlmssp_direction direction,
DATA_BLOB *sig,
BOOL encrypt_sig)
{
if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
HMACMD5Context ctx;
uchar seq_num[4];
uchar digest[16];
*sig = data_blob(NULL, NTLMSSP_SIG_SIZE);
if (!sig->data) {
return NT_STATUS_NO_MEMORY;
}
switch (direction) {
case NTLMSSP_SEND:
DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
ntlmssp_state->ntlm2_send_seq_num,
(unsigned int)length,
(unsigned int)pdu_length));
SIVAL(seq_num, 0, ntlmssp_state->ntlm2_send_seq_num);
ntlmssp_state->ntlm2_send_seq_num++;
hmac_md5_init_limK_to_64(ntlmssp_state->send_sign_key, 16, &ctx);
break;
case NTLMSSP_RECEIVE:
DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
ntlmssp_state->ntlm2_recv_seq_num,
(unsigned int)length,
(unsigned int)pdu_length));
SIVAL(seq_num, 0, ntlmssp_state->ntlm2_recv_seq_num);
ntlmssp_state->ntlm2_recv_seq_num++;
hmac_md5_init_limK_to_64(ntlmssp_state->recv_sign_key, 16, &ctx);
break;
}
dump_data_pw("pdu data ", whole_pdu, pdu_length);
hmac_md5_update(seq_num, 4, &ctx);
hmac_md5_update(whole_pdu, pdu_length, &ctx);
hmac_md5_final(digest, &ctx);
if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
switch (direction) {
case NTLMSSP_SEND:
smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, digest, 8);
break;
case NTLMSSP_RECEIVE:
smb_arc4_crypt(ntlmssp_state->recv_seal_arc4_state, digest, 8);
break;
}
}
SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
memcpy(sig->data + 4, digest, 8);
memcpy(sig->data + 12, seq_num, 4);
dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
} else {
uint32 crc;
crc = crc32_calc_buffer((const char *)data, length);
if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) {
return NT_STATUS_NO_MEMORY;
}
ntlmssp_state->ntlmv1_seq_num++;
dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmv1_arc4_state,
sizeof(ntlmssp_state->ntlmv1_arc4_state));
smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
}
return NT_STATUS_OK;
}
NTSTATUS ntlmssp_sign_packet(NTLMSSP_STATE *ntlmssp_state,
const uchar *data, size_t length,
const uchar *whole_pdu, size_t pdu_length,
DATA_BLOB *sig)
{
NTSTATUS nt_status;
if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) {
DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
return NT_STATUS_INVALID_PARAMETER;
}
if (!ntlmssp_state->session_key.length) {
DEBUG(3, ("NO session key, cannot check sign packet\n"));
return NT_STATUS_NO_USER_SESSION_KEY;
}
nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
data, length,
whole_pdu, pdu_length,
NTLMSSP_SEND, sig, True);
return nt_status;
}
/**
* Check the signature of an incoming packet
* @note caller *must* check that the signature is the size it expects
*
*/
NTSTATUS ntlmssp_check_packet(NTLMSSP_STATE *ntlmssp_state,
const uchar *data, size_t length,
const uchar *whole_pdu, size_t pdu_length,
const DATA_BLOB *sig)
{
DATA_BLOB local_sig;
NTSTATUS nt_status;
if (!ntlmssp_state->session_key.length) {
DEBUG(3, ("NO session key, cannot check packet signature\n"));
return NT_STATUS_NO_USER_SESSION_KEY;
}
if (sig->length < 8) {
DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
(unsigned long)sig->length));
}
nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
data, length,
whole_pdu, pdu_length,
NTLMSSP_RECEIVE, &local_sig, True);
if (!NT_STATUS_IS_OK(nt_status)) {
DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status)));
data_blob_free(&local_sig);
return nt_status;
}
if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
if (local_sig.length != sig->length ||
memcmp(local_sig.data, sig->data, sig->length) != 0) {
DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
dump_data(5, (const char *)local_sig.data, local_sig.length);
DEBUG(5, ("BAD SIG: got signature of\n"));
dump_data(5, (const char *)sig->data, sig->length);
DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
data_blob_free(&local_sig);
return NT_STATUS_ACCESS_DENIED;
}
} else {
if (local_sig.length != sig->length ||
memcmp(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
dump_data(5, (const char *)local_sig.data, local_sig.length);
DEBUG(5, ("BAD SIG: got signature of\n"));
dump_data(5, (const char *)sig->data, sig->length);
DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
data_blob_free(&local_sig);
return NT_STATUS_ACCESS_DENIED;
}
}
dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
data_blob_free(&local_sig);
return NT_STATUS_OK;
}
/**
* Seal data with the NTLMSSP algorithm
*
*/
NTSTATUS ntlmssp_seal_packet(NTLMSSP_STATE *ntlmssp_state,
uchar *data, size_t length,
uchar *whole_pdu, size_t pdu_length,
DATA_BLOB *sig)
{
if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL)) {
DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
return NT_STATUS_INVALID_PARAMETER;
}
if (!ntlmssp_state->session_key.length) {
DEBUG(3, ("NO session key, cannot seal packet\n"));
return NT_STATUS_NO_USER_SESSION_KEY;
}
DEBUG(10,("ntlmssp_seal_data: seal\n"));
dump_data_pw("ntlmssp clear data\n", data, length);
if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
/* The order of these two operations matters - we must first seal the packet,
then seal the sequence number - this is becouse the send_seal_hash is not
constant, but is is rather updated with each iteration */
NTSTATUS nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
data, length,
whole_pdu, pdu_length,
NTLMSSP_SEND, sig, False);
if (!NT_STATUS_IS_OK(nt_status)) {
return nt_status;
}
smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, data, length);
if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, sig->data+4, 8);
}
} else {
uint32 crc;
crc = crc32_calc_buffer((const char *)data, length);
if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) {
return NT_STATUS_NO_MEMORY;
}
/* The order of these two operations matters - we must first seal the packet,
then seal the sequence number - this is becouse the ntlmv1_arc4_state is not
constant, but is is rather updated with each iteration */
dump_data_pw("ntlmv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
sizeof(ntlmssp_state->ntlmv1_arc4_state));
smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, data, length);
dump_data_pw("ntlmv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
sizeof(ntlmssp_state->ntlmv1_arc4_state));
smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
ntlmssp_state->ntlmv1_seq_num++;
}
dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
dump_data_pw("ntlmssp sealed data\n", data, length);
return NT_STATUS_OK;
}
/**
* Unseal data with the NTLMSSP algorithm
*
*/
NTSTATUS ntlmssp_unseal_packet(NTLMSSP_STATE *ntlmssp_state,
uchar *data, size_t length,
uchar *whole_pdu, size_t pdu_length,
DATA_BLOB *sig)
{
if (!ntlmssp_state->session_key.length) {
DEBUG(3, ("NO session key, cannot unseal packet\n"));
return NT_STATUS_NO_USER_SESSION_KEY;
}
DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
dump_data_pw("ntlmssp sealed data\n", data, length);
if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
/* First unseal the data. */
smb_arc4_crypt(ntlmssp_state->recv_seal_arc4_state, data, length);
dump_data_pw("ntlmv2 clear data\n", data, length);
} else {
smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, data, length);
dump_data_pw("ntlmv1 clear data\n", data, length);
}
return ntlmssp_check_packet(ntlmssp_state, data, length, whole_pdu, pdu_length, sig);
}
/**
Initialise the state for NTLMSSP signing.
*/
NTSTATUS ntlmssp_sign_init(NTLMSSP_STATE *ntlmssp_state)
{
unsigned char p24[24];
TALLOC_CTX *mem_ctx;
ZERO_STRUCT(p24);
mem_ctx = talloc_init("weak_keys");
if (!mem_ctx) {
return NT_STATUS_NO_MEMORY;
}
DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
debug_ntlmssp_flags(ntlmssp_state->neg_flags);
if (ntlmssp_state->session_key.length < 8) {
TALLOC_FREE(mem_ctx);
DEBUG(3, ("NO session key, cannot intialise signing\n"));
return NT_STATUS_NO_USER_SESSION_KEY;
}
if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
DATA_BLOB weak_session_key = ntlmssp_state->session_key;
const char *send_sign_const;
const char *send_seal_const;
const char *recv_sign_const;
const char *recv_seal_const;
switch (ntlmssp_state->role) {
case NTLMSSP_CLIENT:
send_sign_const = CLI_SIGN;
send_seal_const = CLI_SEAL;
recv_sign_const = SRV_SIGN;
recv_seal_const = SRV_SEAL;
break;
case NTLMSSP_SERVER:
send_sign_const = SRV_SIGN;
send_seal_const = SRV_SEAL;
recv_sign_const = CLI_SIGN;
recv_seal_const = CLI_SEAL;
break;
default:
TALLOC_FREE(mem_ctx);
return NT_STATUS_INTERNAL_ERROR;
}
/**
Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
We probably should have some parameters to control this, once we get NTLM2 working.
*/
if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
;
} else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
weak_session_key.length = 7;
} else { /* forty bits */
weak_session_key.length = 5;
}
dump_data_pw("NTLMSSP weakend master key:\n",
weak_session_key.data,
weak_session_key.length);
/* SEND: sign key */
calc_ntlmv2_key(ntlmssp_state->send_sign_key,
ntlmssp_state->session_key, send_sign_const);
dump_data_pw("NTLMSSP send sign key:\n",
ntlmssp_state->send_sign_key, 16);
/* SEND: seal ARCFOUR pad */
calc_ntlmv2_key(ntlmssp_state->send_seal_key,
weak_session_key, send_seal_const);
dump_data_pw("NTLMSSP send seal key:\n",
ntlmssp_state->send_seal_key, 16);
smb_arc4_init(ntlmssp_state->send_seal_arc4_state,
ntlmssp_state->send_seal_key, 16);
dump_data_pw("NTLMSSP send seal arc4 state:\n",
ntlmssp_state->send_seal_arc4_state,
sizeof(ntlmssp_state->send_seal_arc4_state));
/* RECV: sign key */
calc_ntlmv2_key(ntlmssp_state->recv_sign_key,
ntlmssp_state->session_key, recv_sign_const);
dump_data_pw("NTLMSSP recv send sign key:\n",
ntlmssp_state->recv_sign_key, 16);
/* RECV: seal ARCFOUR pad */
calc_ntlmv2_key(ntlmssp_state->recv_seal_key,
weak_session_key, recv_seal_const);
dump_data_pw("NTLMSSP recv seal key:\n",
ntlmssp_state->recv_seal_key, 16);
smb_arc4_init(ntlmssp_state->recv_seal_arc4_state,
ntlmssp_state->recv_seal_key, 16);
dump_data_pw("NTLMSSP recv seal arc4 state:\n",
ntlmssp_state->recv_seal_arc4_state,
sizeof(ntlmssp_state->recv_seal_arc4_state));
ntlmssp_state->ntlm2_send_seq_num = 0;
ntlmssp_state->ntlm2_recv_seq_num = 0;
} else {
#if 0
/* Hmmm. Shouldn't we also weaken keys for ntlmv1 ? JRA. */
DATA_BLOB weak_session_key = ntlmssp_state->session_key;
/**
Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
We probably should have some parameters to control this, once we get NTLM2 working.
*/
if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
;
} else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
weak_session_key.length = 6;
} else { /* forty bits */
weak_session_key.length = 5;
}
dump_data_pw("NTLMSSP weakend master key:\n",
weak_session_key.data,
weak_session_key.length);
#endif
DATA_BLOB weak_session_key = ntlmssp_weaken_keys(ntlmssp_state, mem_ctx);
DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
smb_arc4_init(ntlmssp_state->ntlmv1_arc4_state,
weak_session_key.data, weak_session_key.length);
dump_data_pw("NTLMv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
sizeof(ntlmssp_state->ntlmv1_arc4_state));
ntlmssp_state->ntlmv1_seq_num = 0;
}
TALLOC_FREE(mem_ctx);
return NT_STATUS_OK;
}
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