ntlmssp.c

samba-3.0.22.tar.gz 编译smb服务器的源码

 it only occours for LM_KEY connections, and this is controlled
 by the client lanman auth/lanman auth parameters, it isn't too bad.
*/

DATA_BLOB ntlmssp_weaken_keys(NTLMSSP_STATE *ntlmssp_state, TALLOC_CTX *mem_ctx)
{
	DATA_BLOB weakened_key = data_blob_talloc(mem_ctx,
					ntlmssp_state->session_key.data,
					ntlmssp_state->session_key.length);

	/* Nothing to weaken.  We certainly don't want to 'extend' the length... */
	if (weakened_key.length < 16) {
		/* perhaps there was no key? */
		return weakened_key;
	}

	/* Key weakening not performed on the master key for NTLM2
	   and does not occour for NTLM1.  Therefore we only need
	   to do this for the LM_KEY.
	*/

	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) {
		/* LM key doesn't support 128 bit crypto, so this is
		 * the best we can do.  If you negotiate 128 bit, but
		 * not 56, you end up with 40 bit... */
		if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
			weakened_key.data[7] = 0xa0;
		} else { /* forty bits */
			weakened_key.data[5] = 0xe5;
			weakened_key.data[6] = 0x38;
			weakened_key.data[7] = 0xb0;
		}
		weakened_key.length = 8;
	}
	return weakened_key;
}

/**
 * Next state function for the Negotiate packet
 * 
 * @param ntlmssp_state NTLMSSP State
 * @param request The request, as a DATA_BLOB
 * @param request The reply, as an allocated DATA_BLOB, caller to free.
 * @return Errors or MORE_PROCESSING_REQUIRED if a reply is sent. 
 */

static NTSTATUS ntlmssp_server_negotiate(struct ntlmssp_state *ntlmssp_state,
					 const DATA_BLOB request, DATA_BLOB *reply) 
{
	DATA_BLOB struct_blob;
	fstring dnsname, dnsdomname;
	uint32 neg_flags = 0;
	uint32 ntlmssp_command, chal_flags;
	const uint8 *cryptkey;
	const char *target_name;

	/* parse the NTLMSSP packet */
#if 0
	file_save("ntlmssp_negotiate.dat", request.data, request.length);
#endif

	if (request.length) {
		if ((request.length < 16) || !msrpc_parse(&request, "Cdd",
							"NTLMSSP",
							&ntlmssp_command,
							&neg_flags)) {
			DEBUG(1, ("ntlmssp_server_negotiate: failed to parse NTLMSSP Negotiate of length %u\n",
				(unsigned int)request.length));
			dump_data(2, (const char *)request.data, request.length);
			return NT_STATUS_INVALID_PARAMETER;
		}
		debug_ntlmssp_flags(neg_flags);
	}
	
	ntlmssp_handle_neg_flags(ntlmssp_state, neg_flags, lp_lanman_auth());

	/* Ask our caller what challenge they would like in the packet */
	cryptkey = ntlmssp_state->get_challenge(ntlmssp_state);

	/* Check if we may set the challenge */
	if (!ntlmssp_state->may_set_challenge(ntlmssp_state)) {
		ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_NTLM2;
	}

	/* The flags we send back are not just the negotiated flags,
	 * they are also 'what is in this packet'.  Therfore, we
	 * operate on 'chal_flags' from here on 
	 */

	chal_flags = ntlmssp_state->neg_flags;

	/* get the right name to fill in as 'target' */
	target_name = ntlmssp_target_name(ntlmssp_state, 
					  neg_flags, &chal_flags); 
	if (target_name == NULL) 
		return NT_STATUS_INVALID_PARAMETER;

	ntlmssp_state->chal = data_blob_talloc(ntlmssp_state->mem_ctx, cryptkey, 8);
	ntlmssp_state->internal_chal = data_blob_talloc(ntlmssp_state->mem_ctx, cryptkey, 8);
	

	/* This should be a 'netbios domain -> DNS domain' mapping */
	dnsdomname[0] = '\0';
	get_mydnsdomname(dnsdomname);
	strlower_m(dnsdomname);
	
	dnsname[0] = '\0';
	get_mydnsfullname(dnsname);
	
	/* This creates the 'blob' of names that appears at the end of the packet */
	if (chal_flags & NTLMSSP_CHAL_TARGET_INFO) 
	{
		msrpc_gen(&struct_blob, "aaaaa",
			  NTLMSSP_NAME_TYPE_DOMAIN, target_name,
			  NTLMSSP_NAME_TYPE_SERVER, ntlmssp_state->get_global_myname(),
			  NTLMSSP_NAME_TYPE_DOMAIN_DNS, dnsdomname,
			  NTLMSSP_NAME_TYPE_SERVER_DNS, dnsname,
			  0, "");
	} else {
		struct_blob = data_blob(NULL, 0);
	}

	{
		/* Marshel the packet in the right format, be it unicode or ASCII */
		const char *gen_string;
		if (ntlmssp_state->unicode) {
			gen_string = "CdUdbddB";
		} else {
			gen_string = "CdAdbddB";
		}
		
		msrpc_gen(reply, gen_string,
			  "NTLMSSP", 
			  NTLMSSP_CHALLENGE,
			  target_name,
			  chal_flags,
			  cryptkey, 8,
			  0, 0,
			  struct_blob.data, struct_blob.length);
	}
		
	data_blob_free(&struct_blob);

	ntlmssp_state->expected_state = NTLMSSP_AUTH;

	return NT_STATUS_MORE_PROCESSING_REQUIRED;
}

/**
 * Next state function for the Authenticate packet
 * 
 * @param ntlmssp_state NTLMSSP State
 * @param request The request, as a DATA_BLOB
 * @param request The reply, as an allocated DATA_BLOB, caller to free.
 * @return Errors or NT_STATUS_OK. 
 */

static NTSTATUS ntlmssp_server_auth(struct ntlmssp_state *ntlmssp_state,
				    const DATA_BLOB request, DATA_BLOB *reply) 
{
	DATA_BLOB encrypted_session_key = data_blob(NULL, 0);
	DATA_BLOB user_session_key = data_blob(NULL, 0);
	DATA_BLOB lm_session_key = data_blob(NULL, 0);
	DATA_BLOB session_key = data_blob(NULL, 0);
	uint32 ntlmssp_command, auth_flags;
	NTSTATUS nt_status = NT_STATUS_OK;

	/* used by NTLM2 */
	BOOL doing_ntlm2 = False;

	uchar session_nonce[16];
	uchar session_nonce_hash[16];

	const char *parse_string;
	char *domain = NULL;
	char *user = NULL;
	char *workstation = NULL;

	/* parse the NTLMSSP packet */
	*reply = data_blob(NULL, 0);

#if 0
	file_save("ntlmssp_auth.dat", request.data, request.length);
#endif

	if (ntlmssp_state->unicode) {
		parse_string = "CdBBUUUBd";
	} else {
		parse_string = "CdBBAAABd";
	}

	data_blob_free(&ntlmssp_state->lm_resp);
	data_blob_free(&ntlmssp_state->nt_resp);

	ntlmssp_state->user = NULL;
	ntlmssp_state->domain = NULL;
	ntlmssp_state->workstation = NULL;

	/* now the NTLMSSP encoded auth hashes */
	if (!msrpc_parse(&request, parse_string,
			 "NTLMSSP", 
			 &ntlmssp_command, 
			 &ntlmssp_state->lm_resp,
			 &ntlmssp_state->nt_resp,
			 &domain, 
			 &user, 
			 &workstation,
			 &encrypted_session_key,
			 &auth_flags)) {
		SAFE_FREE(domain);
		SAFE_FREE(user);
		SAFE_FREE(workstation);
		data_blob_free(&encrypted_session_key);
		auth_flags = 0;
		
		/* Try again with a shorter string (Win9X truncates this packet) */
		if (ntlmssp_state->unicode) {
			parse_string = "CdBBUUU";
		} else {
			parse_string = "CdBBAAA";
		}

		/* now the NTLMSSP encoded auth hashes */
		if (!msrpc_parse(&request, parse_string,
				 "NTLMSSP", 
				 &ntlmssp_command, 
				 &ntlmssp_state->lm_resp,
				 &ntlmssp_state->nt_resp,
				 &domain, 
				 &user, 
				 &workstation)) {
			DEBUG(1, ("ntlmssp_server_auth: failed to parse NTLMSSP (tried both formats):\n"));
			dump_data(2, (const char *)request.data, request.length);
			SAFE_FREE(domain);
			SAFE_FREE(user);
			SAFE_FREE(workstation);

			return NT_STATUS_INVALID_PARAMETER;
		}
	}

	if (auth_flags)
		ntlmssp_handle_neg_flags(ntlmssp_state, auth_flags, lp_lanman_auth());

	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_domain(ntlmssp_state, domain))) {
		SAFE_FREE(domain);
		SAFE_FREE(user);
		SAFE_FREE(workstation);
		data_blob_free(&encrypted_session_key);
		return nt_status;
	}

	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_username(ntlmssp_state, user))) {
		SAFE_FREE(domain);
		SAFE_FREE(user);
		SAFE_FREE(workstation);
		data_blob_free(&encrypted_session_key);
		return nt_status;
	}

	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_workstation(ntlmssp_state, workstation))) {
		SAFE_FREE(domain);
		SAFE_FREE(user);
		SAFE_FREE(workstation);
		data_blob_free(&encrypted_session_key);
		return nt_status;
	}

	SAFE_FREE(domain);
	SAFE_FREE(user);
	SAFE_FREE(workstation);

	DEBUG(3,("Got user=[%s] domain=[%s] workstation=[%s] len1=%lu len2=%lu\n",
		 ntlmssp_state->user, ntlmssp_state->domain, ntlmssp_state->workstation, (unsigned long)ntlmssp_state->lm_resp.length, (unsigned long)ntlmssp_state->nt_resp.length));

#if 0
	file_save("nthash1.dat",  &ntlmssp_state->nt_resp.data,  &ntlmssp_state->nt_resp.length);
	file_save("lmhash1.dat",  &ntlmssp_state->lm_resp.data,  &ntlmssp_state->lm_resp.length);
#endif

	/* NTLM2 uses a 'challenge' that is made of up both the server challenge, and a 
	   client challenge 
	
	   However, the NTLM2 flag may still be set for the real NTLMv2 logins, be careful.
	*/
	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
		if (ntlmssp_state->nt_resp.length == 24 && ntlmssp_state->lm_resp.length == 24) {
			struct MD5Context md5_session_nonce_ctx;
			SMB_ASSERT(ntlmssp_state->internal_chal.data && ntlmssp_state->internal_chal.length == 8);
			
			doing_ntlm2 = True;

			memcpy(session_nonce, ntlmssp_state->internal_chal.data, 8);
			memcpy(&session_nonce[8], ntlmssp_state->lm_resp.data, 8);
			
			MD5Init(&md5_session_nonce_ctx);
			MD5Update(&md5_session_nonce_ctx, session_nonce, 16);
			MD5Final(session_nonce_hash, &md5_session_nonce_ctx);
			
			ntlmssp_state->chal = data_blob_talloc(ntlmssp_state->mem_ctx, session_nonce_hash, 8);

			/* LM response is no longer useful */
			data_blob_free(&ntlmssp_state->lm_resp);

			/* We changed the effective challenge - set it */
			if (!NT_STATUS_IS_OK(nt_status = ntlmssp_state->set_challenge(ntlmssp_state, &ntlmssp_state->chal))) {
				data_blob_free(&encrypted_session_key);
				return nt_status;
			}

			/* LM Key is incompatible. */
			ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_LM_KEY;
		}
	}

	/*
	 * Note we don't check here for NTLMv2 auth settings. If NTLMv2 auth
	 * is required (by "ntlm auth = no" and "lm auth = no" being set in the
	 * smb.conf file) and no NTLMv2 response was sent then the password check
	 * will fail here. JRA.
	 */

	/* Finally, actually ask if the password is OK */

	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_state->check_password(ntlmssp_state, 
								       &user_session_key, &lm_session_key))) {
		data_blob_free(&encrypted_session_key);
		return nt_status;
	}

	dump_data_pw("NT session key:\n", user_session_key.data, user_session_key.length);
	dump_data_pw("LM first-8:\n", lm_session_key.data, lm_session_key.length);

	/* Handle the different session key derivation for NTLM2 */
	if (doing_ntlm2) {
		if (user_session_key.data && user_session_key.length == 16) {
			session_key = data_blob_talloc(ntlmssp_state->mem_ctx, NULL, 16);
			hmac_md5(user_session_key.data, session_nonce, 
				 sizeof(session_nonce), session_key.data);
			DEBUG(10,("ntlmssp_server_auth: Created NTLM2 session key.\n"));
			dump_data_pw("NTLM2 session key:\n", session_key.data, session_key.length);
			
		} else {
			DEBUG(10,("ntlmssp_server_auth: Failed to create NTLM2 session key.\n"));
			session_key = data_blob(NULL, 0);
		}
	} else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) {
		if (lm_session_key.data && lm_session_key.length >= 8) {
			if (ntlmssp_state->lm_resp.data && ntlmssp_state->lm_resp.length == 24) {
				session_key = data_blob_talloc(ntlmssp_state->mem_ctx, NULL, 16);
				SMBsesskeygen_lm_sess_key(lm_session_key.data, ntlmssp_state->lm_resp.data, 
							  session_key.data);
				DEBUG(10,("ntlmssp_server_auth: Created NTLM session key.\n"));
				dump_data_pw("LM session key:\n", session_key.data, session_key.length);
			} else {
				/* use the key unmodified - it's
				 * probably a NULL key from the guest
				 * login */
				session_key = lm_session_key;
			}
		} else {
			DEBUG(10,("ntlmssp_server_auth: Failed to create NTLM session key.\n"));
			session_key = data_blob(NULL, 0);
		}
	} else if (user_session_key.data) {
		session_key = user_session_key;
		DEBUG(10,("ntlmssp_server_auth: Using unmodified nt session key.\n"));
		dump_data_pw("unmodified session key:\n", session_key.data, session_key.length);
	} else if (lm_session_key.data) {
		session_key = lm_session_key;
		DEBUG(10,("ntlmssp_server_auth: Using unmodified lm session key.\n"));
		dump_data_pw("unmodified session key:\n", session_key.data, session_key.length);
	} else {
		DEBUG(10,("ntlmssp_server_auth: Failed to create unmodified session key.\n"));
		session_key = data_blob(NULL, 0);
	}

	/* With KEY_EXCH, the client supplies the proposed session key, 
	   but encrypts it with the long-term key */
	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
		if (!encrypted_session_key.data || encrypted_session_key.length != 16) {
			data_blob_free(&encrypted_session_key);
			DEBUG(1, ("Client-supplied KEY_EXCH session key was of invalid length (%u)!\n", 
				  (unsigned int)encrypted_session_key.length));
			return NT_STATUS_INVALID_PARAMETER;
		} else if (!session_key.data || session_key.length != 16) {
			DEBUG(5, ("server session key is invalid (len == %u), cannot do KEY_EXCH!\n", 
				  (unsigned int)session_key.length));