r6458: Split up NTLMSSP into a new directory, and into seperate files for the

client and server logic code.  In future, this may allow us to build
only the NTLMSSP client, and not the server, but in the short-term, it
allows me greater sainity in moving around these files.

Andrew Bartlett
(This used to be commit 2f22841c6753e3d5816c12bd463b71f74e1d8796)

1 files changed, 556 insertions, 0 deletions

diff --git a/source4/auth/ntlmssp/ntlmssp_sign.c b/source4/auth/ntlmssp/ntlmssp_sign.c
new file mode 100644
index 0000000000..222cb3e607
--- /dev/null
+++ b/source4/auth/ntlmssp/ntlmssp_sign.c
@@ -0,0 +1,556 @@
+/* 
+ *  Unix SMB/CIFS implementation.
+ *  Version 3.0
+ *  NTLMSSP Signing routines
+ *  Copyright (C) Luke Kenneth Casson Leighton 1996-2001
+ *  Copyright (C) Andrew Bartlett <abartlet@samba.org> 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"
+#include "auth/auth.h"
+#include "auth/ntlmssp/ntlmssp.h"
+#include "lib/crypto/crypto.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(TALLOC_CTX *mem_ctx, 
+			    DATA_BLOB *subkey,
+			    DATA_BLOB session_key, 
+			    const char *constant)
+{
+	struct MD5Context ctx3;
+	*subkey = data_blob_talloc(mem_ctx, NULL, 16);
+	MD5Init(&ctx3);
+	MD5Update(&ctx3, session_key.data, session_key.length);
+	MD5Update(&ctx3, constant, strlen(constant)+1);
+	MD5Final(subkey->data, &ctx3);
+}
+
+enum ntlmssp_direction {
+	NTLMSSP_SEND,
+	NTLMSSP_RECEIVE
+};
+
+static NTSTATUS ntlmssp_make_packet_signature(struct ntlmssp_state *ntlmssp_state,
+					      TALLOC_CTX *sig_mem_ctx, 
+					      const uint8_t *data, size_t length, 
+					      const uint8_t *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;
+		uint8_t digest[16];
+		uint8_t seq_num[4];
+
+		*sig = data_blob_talloc(sig_mem_ctx, NULL, NTLMSSP_SIG_SIZE);
+		if (!sig->data) {
+			return NT_STATUS_NO_MEMORY;
+		}
+			
+		switch (direction) {
+		case NTLMSSP_SEND:
+			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.data, 
+						 ntlmssp_state->send_sign_key.length, &ctx);
+			break;
+		case NTLMSSP_RECEIVE:
+			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.data, 
+						 ntlmssp_state->recv_sign_key.length, &ctx);
+			break;
+		}
+		hmac_md5_update(seq_num, sizeof(seq_num), &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:
+				arcfour_crypt_sbox(ntlmssp_state->send_seal_hash, digest, 8);
+				break;
+			case NTLMSSP_RECEIVE:
+				arcfour_crypt_sbox(ntlmssp_state->recv_seal_hash, digest, 8);
+				break;
+			}
+		}
+
+		SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
+		memcpy(sig->data + 4, digest, 8);
+		memcpy(sig->data + 12, seq_num, 4);
+
+	} else {
+		uint32_t crc;
+		crc = crc32_calc_buffer(data, length);
+		if (!msrpc_gen(sig_mem_ctx, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlm_seq_num)) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		ntlmssp_state->ntlm_seq_num++;
+
+		arcfour_crypt_sbox(ntlmssp_state->ntlmssp_hash, sig->data+4, sig->length-4);
+	}
+	dump_data_pw("calculated ntlmssp signature\n", sig->data, sig->length);
+	return NT_STATUS_OK;
+}
+
+NTSTATUS gensec_ntlmssp_sign_packet(struct gensec_security *gensec_security, 
+					   TALLOC_CTX *sig_mem_ctx, 
+					   const uint8_t *data, size_t length, 
+					   const uint8_t *whole_pdu, size_t pdu_length, 
+					   DATA_BLOB *sig)
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
+	struct ntlmssp_state *ntlmssp_state = gensec_ntlmssp_state->ntlmssp_state;
+
+	if (!ntlmssp_state->session_key.length) {
+		DEBUG(3, ("NO session key, cannot check sign packet\n"));
+		return NT_STATUS_NO_USER_SESSION_KEY;
+	}
+	
+	if (!ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) {
+		DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	return ntlmssp_make_packet_signature(ntlmssp_state, sig_mem_ctx, 
+					     data, length, 
+					     whole_pdu, pdu_length, 
+					     NTLMSSP_SEND, sig, True);
+}
+
+/**
+ * Check the signature of an incoming packet 
+ *
+ */
+
+NTSTATUS gensec_ntlmssp_check_packet(struct gensec_security *gensec_security, 
+				     TALLOC_CTX *sig_mem_ctx, 
+				     const uint8_t *data, size_t length, 
+				     const uint8_t *whole_pdu, size_t pdu_length, 
+				     const DATA_BLOB *sig)
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
+	struct ntlmssp_state *ntlmssp_state = gensec_ntlmssp_state->ntlmssp_state;
+
+	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, sig_mem_ctx, 
+						  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)));
+		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, local_sig.data, local_sig.length);
+			
+			DEBUG(5, ("BAD SIG: got signature of\n"));
+			dump_data(5, sig->data, sig->length);
+			
+			DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
+			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, local_sig.data, local_sig.length);
+			
+			DEBUG(5, ("BAD SIG: got signature of\n"));
+			dump_data(5, sig->data, sig->length);
+			
+			DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
+			return NT_STATUS_ACCESS_DENIED;
+		}
+	}
+	dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
+
+	return NT_STATUS_OK;
+}
+
+
+/**
+ * Seal data with the NTLMSSP algorithm
+ *
+ */
+
+NTSTATUS gensec_ntlmssp_seal_packet(struct gensec_security *gensec_security, 
+				    TALLOC_CTX *sig_mem_ctx, 
+				    uint8_t *data, size_t length, 
+				    const uint8_t *whole_pdu, size_t pdu_length, 
+				    DATA_BLOB *sig)
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
+	struct ntlmssp_state *ntlmssp_state = gensec_ntlmssp_state->ntlmssp_state;
+	NTSTATUS nt_status;
+	if (!ntlmssp_state->session_key.length) {
+		DEBUG(3, ("NO session key, cannot seal packet\n"));
+		return NT_STATUS_NO_USER_SESSION_KEY;
+	}
+
+	if (!ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) {
+		DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	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 */
+		nt_status = ntlmssp_make_packet_signature(ntlmssp_state, sig_mem_ctx, 
+							  data, length, 
+							  whole_pdu, pdu_length, 
+							  NTLMSSP_SEND, sig, False);
+		arcfour_crypt_sbox(ntlmssp_state->send_seal_hash, data, length);
+		if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
+			arcfour_crypt_sbox(ntlmssp_state->send_seal_hash, sig->data+4, 8);
+		}
+	} else {
+		uint32_t crc;
+		crc = crc32_calc_buffer(data, length);
+		if (!msrpc_gen(sig_mem_ctx, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlm_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 ntlmssp_hash is not
+		   constant, but is is rather updated with each
+		   iteration */
+
+		arcfour_crypt_sbox(ntlmssp_state->ntlmssp_hash, data, length);
+		arcfour_crypt_sbox(ntlmssp_state->ntlmssp_hash, sig->data+4, sig->length-4);
+		/* increment counter on send */
+		ntlmssp_state->ntlm_seq_num++;
+		nt_status = NT_STATUS_OK;
+	}
+	dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
+	dump_data_pw("ntlmssp sealed data\n", data, length);
+
+
+	return nt_status;
+}
+
+/**
+ * Unseal data with the NTLMSSP algorithm
+ *
+ */
+
+/*
+  wrappers for the ntlmssp_*() functions
+*/
+NTSTATUS gensec_ntlmssp_unseal_packet(struct gensec_security *gensec_security, 
+				      TALLOC_CTX *sig_mem_ctx, 
+				      uint8_t *data, size_t length, 
+				      const uint8_t *whole_pdu, size_t pdu_length, 
+				      const DATA_BLOB *sig)
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
+	struct ntlmssp_state *ntlmssp_state = gensec_ntlmssp_state->ntlmssp_state;
+	DATA_BLOB local_sig;
+	NTSTATUS nt_status;
+	if (!ntlmssp_state->session_key.length) {
+		DEBUG(3, ("NO session key, cannot unseal packet\n"));
+		return NT_STATUS_NO_USER_SESSION_KEY;
+	}
+
+	dump_data_pw("ntlmssp sealed data\n", data, length);
+	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
+		arcfour_crypt_sbox(ntlmssp_state->recv_seal_hash, data, length);
+
+		nt_status = ntlmssp_make_packet_signature(ntlmssp_state, sig_mem_ctx, 
+							  data, length, 
+							  whole_pdu, pdu_length, 
+							  NTLMSSP_RECEIVE, &local_sig, True);
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			return nt_status;
+		}
+
+		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, local_sig.data, local_sig.length);
+			
+			DEBUG(5, ("BAD SIG: got signature of\n"));
+			dump_data(5, sig->data, sig->length);
+			
+			DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
+			return NT_STATUS_ACCESS_DENIED;
+		}
+
+		dump_data_pw("ntlmssp clear data\n", data, length);
+		return NT_STATUS_OK;
+	} else {
+		arcfour_crypt_sbox(ntlmssp_state->ntlmssp_hash, data, length);
+		dump_data_pw("ntlmssp clear data\n", data, length);
+		return gensec_ntlmssp_check_packet(gensec_security, sig_mem_ctx, data, length, whole_pdu, pdu_length, sig);
+	}
+}
+
+/**
+   Initialise the state for NTLMSSP signing.
+*/
+NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
+{
+	uint8_t p24[24];
+	ZERO_STRUCT(p24);
+
+	DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
+	debug_ntlmssp_flags(ntlmssp_state->neg_flags);
+
+	if (!ntlmssp_state->session_key.length) {
+		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:
+			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 = 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);
+
+		/* SEND */
+		calc_ntlmv2_key(ntlmssp_state, 
+				&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.data, 
+			     ntlmssp_state->send_sign_key.length);
+		
+		calc_ntlmv2_key(ntlmssp_state, 
+				&ntlmssp_state->send_seal_key, 
+				weak_session_key, send_seal_const);
+		dump_data_pw("NTLMSSP send seal key:\n",
+			     ntlmssp_state->send_seal_key.data, 
+			     ntlmssp_state->send_seal_key.length);
+
+		arcfour_init(ntlmssp_state->send_seal_hash, 
+			     &ntlmssp_state->send_seal_key);
+
+		dump_data_pw("NTLMSSP send sesl hash:\n", 
+			     ntlmssp_state->send_seal_hash, 
+			     sizeof(ntlmssp_state->send_seal_hash));
+
+		/* RECV */
+		calc_ntlmv2_key(ntlmssp_state, 
+				&ntlmssp_state->recv_sign_key, 
+				ntlmssp_state->session_key, recv_sign_const);
+		dump_data_pw("NTLMSSP recv sign key:\n",
+			     ntlmssp_state->recv_sign_key.data, 
+			     ntlmssp_state->recv_sign_key.length);
+
+		calc_ntlmv2_key(ntlmssp_state, 
+				&ntlmssp_state->recv_seal_key, 
+				weak_session_key, recv_seal_const);
+		dump_data_pw("NTLMSSP recv seal key:\n",
+			     ntlmssp_state->recv_seal_key.data, 
+			     ntlmssp_state->recv_seal_key.length);
+		arcfour_init(ntlmssp_state->recv_seal_hash, 
+			     &ntlmssp_state->recv_seal_key);
+
+		dump_data_pw("NTLMSSP receive seal hash:\n", 
+			     ntlmssp_state->recv_seal_hash, 
+			     sizeof(ntlmssp_state->recv_seal_hash));
+	} else {
+		DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
+
+		arcfour_init(ntlmssp_state->ntlmssp_hash, 
+			     &ntlmssp_state->session_key);
+		dump_data_pw("NTLMSSP hash:\n", ntlmssp_state->ntlmssp_hash,
+			     sizeof(ntlmssp_state->ntlmssp_hash));
+	}
+
+	ntlmssp_state->ntlm_seq_num = 0;
+	ntlmssp_state->ntlm2_send_seq_num = 0;
+	ntlmssp_state->ntlm2_recv_seq_num = 0;
+
+	return NT_STATUS_OK;
+}
+
+size_t gensec_ntlmssp_sig_size(struct gensec_security *gensec_security) 
+{
+	return NTLMSSP_SIG_SIZE;
+}
+
+NTSTATUS gensec_ntlmssp_wrap(struct gensec_security *gensec_security, 
+			     TALLOC_CTX *sig_mem_ctx, 
+			     const DATA_BLOB *in, 
+			     DATA_BLOB *out)
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
+	DATA_BLOB sig;
+	NTSTATUS nt_status;
+
+	if (gensec_ntlmssp_state->ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) {
+
+		*out = data_blob_talloc(sig_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
+		memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
+
+	        nt_status = gensec_ntlmssp_seal_packet(gensec_security, sig_mem_ctx, 
+						       out->data + NTLMSSP_SIG_SIZE, 
+						       out->length - NTLMSSP_SIG_SIZE, 
+						       out->data + NTLMSSP_SIG_SIZE, 
+						       out->length - NTLMSSP_SIG_SIZE, 
+						       &sig);
+
+		if (NT_STATUS_IS_OK(nt_status)) {
+			memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE);
+		}
+		return nt_status;
+
+	} else if ((gensec_ntlmssp_state->ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) 
+		   || (gensec_ntlmssp_state->ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_ALWAYS_SIGN)) {
+
+		*out = data_blob_talloc(sig_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
+		memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
+
+	        nt_status = gensec_ntlmssp_sign_packet(gensec_security, sig_mem_ctx, 
+						out->data + NTLMSSP_SIG_SIZE, 
+						out->length - NTLMSSP_SIG_SIZE, 
+						out->data + NTLMSSP_SIG_SIZE, 
+						out->length - NTLMSSP_SIG_SIZE, 
+						&sig);
+
+		if (NT_STATUS_IS_OK(nt_status)) {
+			memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE);
+		}
+		return nt_status;
+
+	} else {
+		*out = *in;
+		return NT_STATUS_OK;
+	}
+}
+
+
+NTSTATUS gensec_ntlmssp_unwrap(struct gensec_security *gensec_security, 
+			       TALLOC_CTX *sig_mem_ctx, 
+			       const DATA_BLOB *in, 
+			       DATA_BLOB *out)
+{
+	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
+	DATA_BLOB sig;
+
+	if (gensec_ntlmssp_state->ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) {
+		if (in->length < NTLMSSP_SIG_SIZE) {
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		sig.data = in->data;
+		sig.length = NTLMSSP_SIG_SIZE;
+
+		*out = data_blob_talloc(sig_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
+		
+	        return gensec_ntlmssp_unseal_packet(gensec_security, sig_mem_ctx, 
+						    out->data, out->length, 
+						    out->data, out->length, 
+						    &sig);
+						  
+	} else if ((gensec_ntlmssp_state->ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) 
+		   || (gensec_ntlmssp_state->ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_ALWAYS_SIGN)) {
+		if (in->length < NTLMSSP_SIG_SIZE) {
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		sig.data = in->data;
+		sig.length = NTLMSSP_SIG_SIZE;
+
+		*out = data_blob_talloc(sig_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
+		
+	        return gensec_ntlmssp_check_packet(gensec_security, sig_mem_ctx, 
+					    out->data, out->length, 
+					    out->data, out->length, 
+					    &sig);
+	} else {
+		*out = *in;
+		return NT_STATUS_OK;
+	}
+}
+