ntlmssp_server.c

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/* 
   Unix SMB/Netbios implementation.
   Version 3.0
   handle NLTMSSP, client server side parsing

   Copyright (C) Andrew Tridgell      2001
   Copyright (C) Andrew Bartlett <[e-mail]> 2001-2005
   Copyright (C) Stefan Metzmacher 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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "auth/ntlmssp/ntlmssp.h"
#include "auth/ntlmssp/msrpc_parse.h"
#include "lib/crypto/crypto.h"
#include "system/filesys.h"
#include "libcli/auth/libcli_auth.h"
#include "auth/credentials/credentials.h"
#include "auth/gensec/gensec.h"
#include "auth/auth.h"
#include "auth/ntlm/auth_proto.h"
#include "param/param.h"
#include "auth/session_proto.h"

/** 
 * Set a username on an NTLMSSP context - ensures it is talloc()ed 
 *
 */

static NTSTATUS ntlmssp_set_username(struct gensec_ntlmssp_state *gensec_ntlmssp_state, const char *user) 
{
	if (!user) {
		/* it should be at least "" */
		DEBUG(1, ("NTLMSSP failed to set username - cannot accept NULL username\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}
	gensec_ntlmssp_state->user = talloc_strdup(gensec_ntlmssp_state, user);
	if (!gensec_ntlmssp_state->user) {
		return NT_STATUS_NO_MEMORY;
	}
	return NT_STATUS_OK;
}

/** 
 * Set a domain on an NTLMSSP context - ensures it is talloc()ed 
 *
 */
static NTSTATUS ntlmssp_set_domain(struct gensec_ntlmssp_state *gensec_ntlmssp_state, const char *domain) 
{
	gensec_ntlmssp_state->domain = talloc_strdup(gensec_ntlmssp_state, domain);
	if (!gensec_ntlmssp_state->domain) {
		return NT_STATUS_NO_MEMORY;
	}
	return NT_STATUS_OK;
}

/** 
 * Set a workstation on an NTLMSSP context - ensures it is talloc()ed 
 *
 */
static NTSTATUS ntlmssp_set_workstation(struct gensec_ntlmssp_state *gensec_ntlmssp_state, const char *workstation) 
{
	gensec_ntlmssp_state->workstation = talloc_strdup(gensec_ntlmssp_state, workstation);
	if (!gensec_ntlmssp_state->workstation) {
		return NT_STATUS_NO_MEMORY;
	}
	return NT_STATUS_OK;
}

/**
 * Determine correct target name flags for reply, given server role 
 * and negotiated flags
 * 
 * @param gensec_ntlmssp_state NTLMSSP State
 * @param neg_flags The flags from the packet
 * @param chal_flags The flags to be set in the reply packet
 * @return The 'target name' string.
 */

static const char *ntlmssp_target_name(struct gensec_ntlmssp_state *gensec_ntlmssp_state,
				       uint32_t neg_flags, uint32_t *chal_flags) 
{
	if (neg_flags & NTLMSSP_REQUEST_TARGET) {
		*chal_flags |= NTLMSSP_CHAL_TARGET_INFO;
		*chal_flags |= NTLMSSP_REQUEST_TARGET;
		if (gensec_ntlmssp_state->server_role == ROLE_STANDALONE) {
			*chal_flags |= NTLMSSP_TARGET_TYPE_SERVER;
			return gensec_ntlmssp_state->server_name;
		} else {
			*chal_flags |= NTLMSSP_TARGET_TYPE_DOMAIN;
			return gensec_ntlmssp_state->domain;
		};
	} else {
		return "";
	}
}



/**
 * Next state function for the Negotiate packet
 * 
 * @param gensec_security GENSEC state
 * @param out_mem_ctx Memory context for *out
 * @param in The request, as a DATA_BLOB.  reply.data must be NULL
 * @param out The reply, as an allocated DATA_BLOB, caller to free.
 * @return Errors or MORE_PROCESSING_REQUIRED if (normal) a reply is required. 
 */

NTSTATUS ntlmssp_server_negotiate(struct gensec_security *gensec_security, 
				  TALLOC_CTX *out_mem_ctx, 
				  const DATA_BLOB in, DATA_BLOB *out) 
{
	struct gensec_ntlmssp_state *gensec_ntlmssp_state = (struct gensec_ntlmssp_state *)gensec_security->private_data;
	DATA_BLOB struct_blob;
	char dnsname[MAXHOSTNAMELEN], dnsdomname[MAXHOSTNAMELEN];
	const char *p;
	uint32_t neg_flags = 0;
	uint32_t ntlmssp_command, chal_flags;
	const uint8_t *cryptkey;
	const char *target_name;

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

	if (in.length) {
		if ((in.length < 16) || !msrpc_parse(out_mem_ctx, 
				 lp_iconv_convenience(gensec_security->lp_ctx),
				 			 &in, "Cdd",
							 "NTLMSSP",
							 &ntlmssp_command,
							 &neg_flags)) {
			DEBUG(1, ("ntlmssp_server_negotiate: failed to parse "
				"NTLMSSP Negotiate of length %u:\n",
				(unsigned int)in.length ));
			dump_data(2, in.data, in.length);
			return NT_STATUS_INVALID_PARAMETER;
		}
		debug_ntlmssp_flags(neg_flags);
	}
	
	ntlmssp_handle_neg_flags(gensec_ntlmssp_state, neg_flags, gensec_ntlmssp_state->allow_lm_key);

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

	/* Check if we may set the challenge */
	if (!gensec_ntlmssp_state->may_set_challenge(gensec_ntlmssp_state)) {
		gensec_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 = gensec_ntlmssp_state->neg_flags;

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

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

	dnsname[0] = '\0';
	if (gethostname(dnsname, sizeof(dnsname)) == -1) {
		DEBUG(0,("gethostname failed\n"));
		return NT_STATUS_UNSUCCESSFUL;
	}

	/* This should be a 'netbios domain -> DNS domain' mapping */
	p = strchr(dnsname, '.');
	if (p != NULL) {
		safe_strcpy(dnsdomname, p+1, sizeof(dnsdomname));
		strlower_m(dnsdomname);
	} else {
		dnsdomname[0] = '\0';
	}
	
	/* This creates the 'blob' of names that appears at the end of the packet */
	if (chal_flags & NTLMSSP_CHAL_TARGET_INFO) 
	{
		const char *target_name_dns = "";
		if (chal_flags |= NTLMSSP_TARGET_TYPE_DOMAIN) {
			target_name_dns = dnsdomname;
		} else if (chal_flags |= NTLMSSP_TARGET_TYPE_SERVER) {
			target_name_dns = dnsname;
		}

		msrpc_gen(out_mem_ctx, 
		          lp_iconv_convenience(gensec_security->lp_ctx),
			  &struct_blob, "aaaaa",
			  NTLMSSP_NAME_TYPE_DOMAIN, target_name,
			  NTLMSSP_NAME_TYPE_SERVER, gensec_ntlmssp_state->server_name,
			  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 (gensec_ntlmssp_state->unicode) {
			gen_string = "CdUdbddB";
		} else {
			gen_string = "CdAdbddB";
		}
		
		msrpc_gen(out_mem_ctx, 
		          lp_iconv_convenience(gensec_security->lp_ctx),
			  out, gen_string,
			  "NTLMSSP", 
			  NTLMSSP_CHALLENGE,
			  target_name,
			  chal_flags,
			  cryptkey, 8,
			  0, 0,
			  struct_blob.data, struct_blob.length);
	}
		
	gensec_ntlmssp_state->expected_state = NTLMSSP_AUTH;

	return NT_STATUS_MORE_PROCESSING_REQUIRED;
}

/**
 * Next state function for the Authenticate packet
 * 
 * @param gensec_ntlmssp_state NTLMSSP State
 * @param request The request, as a DATA_BLOB
 * @return Errors or NT_STATUS_OK. 
 */

static NTSTATUS ntlmssp_server_preauth(struct gensec_ntlmssp_state *gensec_ntlmssp_state,
				       const DATA_BLOB request) 
{
	uint32_t ntlmssp_command, auth_flags;
	NTSTATUS nt_status;

	uint8_t session_nonce_hash[16];

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

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

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

	/* zero these out */
	data_blob_free(&gensec_ntlmssp_state->lm_resp);
	data_blob_free(&gensec_ntlmssp_state->nt_resp);
	data_blob_free(&gensec_ntlmssp_state->encrypted_session_key);

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

	/* now the NTLMSSP encoded auth hashes */
	if (!msrpc_parse(gensec_ntlmssp_state, 
			 lp_iconv_convenience(gensec_ntlmssp_state->gensec_security->lp_ctx),
			 &request, parse_string,
			 "NTLMSSP", 
			 &ntlmssp_command, 
			 &gensec_ntlmssp_state->lm_resp,
			 &gensec_ntlmssp_state->nt_resp,
			 &domain, 
			 &user, 
			 &workstation,
			 &gensec_ntlmssp_state->encrypted_session_key,
			 &auth_flags)) {
		DEBUG(10, ("ntlmssp_server_auth: failed to parse NTLMSSP (nonfatal):\n"));
		dump_data(10, request.data, request.length);

		/* zero this out */
		data_blob_free(&gensec_ntlmssp_state->encrypted_session_key);
		auth_flags = 0;
		
		/* Try again with a shorter string (Win9X truncates this packet) */
		if (gensec_ntlmssp_state->unicode) {
			parse_string = "CdBBUUU";
		} else {
			parse_string = "CdBBAAA";
		}

		/* now the NTLMSSP encoded auth hashes */
		if (!msrpc_parse(gensec_ntlmssp_state, 
			 	 lp_iconv_convenience(gensec_ntlmssp_state->gensec_security->lp_ctx),
				 &request, parse_string,
				 "NTLMSSP", 
				 &ntlmssp_command, 
				 &gensec_ntlmssp_state->lm_resp,
				 &gensec_ntlmssp_state->nt_resp,
				 &domain, 
				 &user, 
				 &workstation)) {
			DEBUG(1, ("ntlmssp_server_auth: failed to parse NTLMSSP:\n"));
			dump_data(2, request.data, request.length);

			return NT_STATUS_INVALID_PARAMETER;
		}
	}

	if (auth_flags)
		ntlmssp_handle_neg_flags(gensec_ntlmssp_state, auth_flags, gensec_ntlmssp_state->allow_lm_key);

	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_domain(gensec_ntlmssp_state, domain))) {
		/* zero this out */
		data_blob_free(&gensec_ntlmssp_state->encrypted_session_key);
		return nt_status;
	}

	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_username(gensec_ntlmssp_state, user))) {
		/* zero this out */
		data_blob_free(&gensec_ntlmssp_state->encrypted_session_key);
		return nt_status;
	}

	if (!NT_STATUS_IS_OK(nt_status = ntlmssp_set_workstation(gensec_ntlmssp_state, workstation))) {
		/* zero this out */
		data_blob_free(&gensec_ntlmssp_state->encrypted_session_key);
		return nt_status;
	}

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

#if 0
	file_save("nthash1.dat",  &gensec_ntlmssp_state->nt_resp.data,  &gensec_ntlmssp_state->nt_resp.length);
	file_save("lmhash1.dat",  &gensec_ntlmssp_state->lm_resp.data,  &gensec_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 (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
		if (gensec_ntlmssp_state->nt_resp.length == 24 && gensec_ntlmssp_state->lm_resp.length == 24) {
			struct MD5Context md5_session_nonce_ctx;
			SMB_ASSERT(gensec_ntlmssp_state->internal_chal.data 
				   && gensec_ntlmssp_state->internal_chal.length == 8);
			
			gensec_ntlmssp_state->doing_ntlm2 = true;

			memcpy(gensec_ntlmssp_state->crypt.ntlm2.session_nonce, gensec_ntlmssp_state->internal_chal.data, 8);
			memcpy(&gensec_ntlmssp_state->crypt.ntlm2.session_nonce[8], gensec_ntlmssp_state->lm_resp.data, 8);
			
			MD5Init(&md5_session_nonce_ctx);
			MD5Update(&md5_session_nonce_ctx, gensec_ntlmssp_state->crypt.ntlm2.session_nonce, 16);
			MD5Final(session_nonce_hash, &md5_session_nonce_ctx);
			
			gensec_ntlmssp_state->chal = data_blob_talloc(gensec_ntlmssp_state, 
							       session_nonce_hash, 8);

			/* LM response is no longer useful, zero it out */
			data_blob_free(&gensec_ntlmssp_state->lm_resp);

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

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

/**
 * Next state function for the Authenticate packet 
 * (after authentication - figures out the session keys etc)
 * 
 * @param gensec_ntlmssp_state NTLMSSP State
 * @return Errors or NT_STATUS_OK. 
 */