s3:ntlmssp Move ntlmssp_sign.c from source3 to common code.

This needs a small re-arrangement of the supporting code.

Andrew Bartlett

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Günther Deschner <gd@samba.org>

4 files changed, 696 insertions, 0 deletions

diff --git a/libcli/auth/ntlmssp.c b/libcli/auth/ntlmssp.c
new file mode 100644
index 0000000000..1be764ec42
--- /dev/null
+++ b/libcli/auth/ntlmssp.c
@@ -0,0 +1,76 @@
+/*
+   Unix SMB/Netbios implementation.
+   Version 3.0
+   handle NLTMSSP, server side
+
+   Copyright (C) Andrew Tridgell      2001
+   Copyright (C) Andrew Bartlett 2001-2003
+   Copyright (C) Andrew Bartlett 2005 (Updated from gensec).
+
+   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 "../libcli/auth/ntlmssp.h"
+#include "../libcli/auth/ntlmssp_private.h"
+
+/**
+ * Print out the NTLMSSP flags for debugging
+ * @param neg_flags The flags from the packet
+ */
+void debug_ntlmssp_flags(uint32_t neg_flags)
+{
+	DEBUG(3,("Got NTLMSSP neg_flags=0x%08x\n", neg_flags));
+
+	if (neg_flags & NTLMSSP_NEGOTIATE_UNICODE)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_UNICODE\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_OEM)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_OEM\n"));
+	if (neg_flags & NTLMSSP_REQUEST_TARGET)
+		DEBUGADD(4, ("  NTLMSSP_REQUEST_TARGET\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_SIGN)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_SIGN\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_SEAL)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_SEAL\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_DATAGRAM)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_DATAGRAM\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_LM_KEY)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_LM_KEY\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_NETWARE)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_NETWARE\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_NTLM)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_NTLM\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_OEM_DOMAIN_SUPPLIED)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_OEM_DOMAIN_SUPPLIED\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_OEM_WORKSTATION_SUPPLIED)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_OEM_WORKSTATION_SUPPLIED\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_THIS_IS_LOCAL_CALL)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_THIS_IS_LOCAL_CALL\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_ALWAYS_SIGN)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_ALWAYS_SIGN\n"));
+	if (neg_flags & NTLMSSP_REQUEST_NON_NT_SESSION_KEY)
+		DEBUGADD(4, ("  NTLMSSP_REQUEST_NON_NT_SESSION_KEY\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_NTLM2)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_NTLM2\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_TARGET_INFO)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_TARGET_INFO\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_VERSION)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_VERSION\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_128)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_128\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_KEY_EXCH\n"));
+	if (neg_flags & NTLMSSP_NEGOTIATE_56)
+		DEBUGADD(4, ("  NTLMSSP_NEGOTIATE_56\n"));
+}
diff --git a/libcli/auth/ntlmssp.h b/libcli/auth/ntlmssp.h
index 97192b8c6f..d0a282c350 100644
--- a/libcli/auth/ntlmssp.h
+++ b/libcli/auth/ntlmssp.h
@@ -137,3 +137,25 @@ struct ntlmssp_state
 
 	union ntlmssp_crypt_state *crypt;
 };
+
+/* The following definitions come from libcli/auth/ntlmssp_sign.c  */
+
+NTSTATUS ntlmssp_sign_packet(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,
+			     DATA_BLOB *sig);
+NTSTATUS ntlmssp_check_packet(struct ntlmssp_state *ntlmssp_state,
+			      const uint8_t *data, size_t length,
+			      const uint8_t *whole_pdu, size_t pdu_length,
+			      const DATA_BLOB *sig) ;
+NTSTATUS ntlmssp_seal_packet(struct ntlmssp_state *ntlmssp_state,
+			     TALLOC_CTX *sig_mem_ctx,
+			     uint8_t *data, size_t length,
+			     const uint8_t *whole_pdu, size_t pdu_length,
+			     DATA_BLOB *sig);
+NTSTATUS ntlmssp_unseal_packet(struct ntlmssp_state *ntlmssp_state,
+			       uint8_t *data, size_t length,
+			       const uint8_t *whole_pdu, size_t pdu_length,
+			       const DATA_BLOB *sig);
+NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state);
diff --git a/libcli/auth/ntlmssp_private.h b/libcli/auth/ntlmssp_private.h
new file mode 100644
index 0000000000..0f0c7dbba9
--- /dev/null
+++ b/libcli/auth/ntlmssp_private.h
@@ -0,0 +1,25 @@
+/*
+ *  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 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/>.
+ */
+
+/* For structures internal to the NTLMSSP implementation that should not be exposed */
+
+/* The following definitions come from libcli/auth/ntlmssp.c  */
+
+void debug_ntlmssp_flags(uint32_t neg_flags);
diff --git a/libcli/auth/ntlmssp_sign.c b/libcli/auth/ntlmssp_sign.c
new file mode 100644
index 0000000000..61b52c6a61
--- /dev/null
+++ b/libcli/auth/ntlmssp_sign.c
@@ -0,0 +1,573 @@
+/*
+ *  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 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 "../libcli/auth/ntlmssp.h"
+#include "../libcli/auth/libcli_auth.h"
+#include "../lib/crypto/md5.h"
+#include "../lib/crypto/arcfour.h"
+#include "../lib/crypto/hmacmd5.h"
+#include "../lib/crypto/crc32.h"
+#include "../libcli/auth/ntlmssp_private.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 the 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 dump_arc4_state(const char *description,
+			    struct arcfour_state *state)
+{
+	dump_data_pw(description, state->sbox, sizeof(state->sbox));
+}
+
+static void calc_ntlmv2_key(uint8_t 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 uint8_t *)constant, strlen(constant)+1);
+	MD5Final(subkey, &ctx3);
+}
+
+enum ntlmssp_direction {
+	NTLMSSP_SEND,
+	NTLMSSP_RECEIVE
+};
+
+struct ntlmssp_crypt_direction {
+	uint32_t seq_num;
+	uint8_t sign_key[16];
+	struct arcfour_state seal_state;
+};
+
+union ntlmssp_crypt_state {
+	/* NTLM */
+	struct ntlmssp_crypt_direction ntlm;
+
+	/* NTLM2 */
+	struct {
+		struct ntlmssp_crypt_direction sending;
+		struct ntlmssp_crypt_direction receiving;
+	} ntlm2;
+};
+
+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:
+			DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
+				ntlmssp_state->crypt->ntlm2.sending.seq_num,
+				(unsigned int)length,
+				(unsigned int)pdu_length));
+
+			SIVAL(seq_num, 0, ntlmssp_state->crypt->ntlm2.sending.seq_num);
+			ntlmssp_state->crypt->ntlm2.sending.seq_num++;
+			hmac_md5_init_limK_to_64(ntlmssp_state->crypt->ntlm2.sending.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->crypt->ntlm2.receiving.seq_num,
+				(unsigned int)length,
+				(unsigned int)pdu_length));
+
+			SIVAL(seq_num, 0, ntlmssp_state->crypt->ntlm2.receiving.seq_num);
+			ntlmssp_state->crypt->ntlm2.receiving.seq_num++;
+			hmac_md5_init_limK_to_64(ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16, &ctx);
+			break;
+		}
+
+		dump_data_pw("pdu data ", whole_pdu, pdu_length);
+
+		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->crypt->ntlm2.sending.seal_state,
+						   digest, 8);
+				break;
+			case NTLMSSP_RECEIVE:
+				arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_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 {
+		bool ok;
+		uint32_t crc;
+
+		crc = crc32_calc_buffer(data, length);
+
+		ok = msrpc_gen(sig_mem_ctx,
+			       sig, "dddd",
+			       NTLMSSP_SIGN_VERSION, 0, crc,
+			       ntlmssp_state->crypt->ntlm.seq_num);
+		if (!ok) {
+			return NT_STATUS_NO_MEMORY;
+		}
+
+		ntlmssp_state->crypt->ntlm.seq_num++;
+
+		dump_arc4_state("ntlmssp hash: \n",
+				&ntlmssp_state->crypt->ntlm.seal_state);
+		arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
+				   sig->data+4, sig->length-4);
+	}
+	return NT_STATUS_OK;
+}
+
+NTSTATUS ntlmssp_sign_packet(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,
+			     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,
+						  sig_mem_ctx,
+						  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(struct ntlmssp_state *ntlmssp_state,
+			      const uint8_t *data, size_t length,
+			      const uint8_t *whole_pdu, size_t pdu_length,
+			      const DATA_BLOB *sig)
+{
+	DATA_BLOB local_sig;
+	NTSTATUS nt_status;
+	TALLOC_CTX *tmp_ctx;
+
+	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));
+	}
+
+	tmp_ctx = talloc_new(ntlmssp_state);
+	if (!tmp_ctx) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
+						  tmp_ctx,
+						  data, length,
+						  whole_pdu, pdu_length,
+						  NTLMSSP_RECEIVE,
+						  &local_sig, true);
+
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		DEBUG(0,("NTLMSSP packet sig creation failed with %s\n",
+			 nt_errstr(nt_status)));
+		talloc_free(tmp_ctx);
+		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"));
+			talloc_free(tmp_ctx);
+			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"));
+			talloc_free(tmp_ctx);
+			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"));
+
+	talloc_free(tmp_ctx);
+	return NT_STATUS_OK;
+}
+
+/**
+ * Seal data with the NTLMSSP algorithm
+ *
+ */
+
+NTSTATUS ntlmssp_seal_packet(struct ntlmssp_state *ntlmssp_state,
+			     TALLOC_CTX *sig_mem_ctx,
+			     uint8_t *data, size_t length,
+			     const uint8_t *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) {
+		NTSTATUS nt_status;
+		/*
+		 * The order of these two operations matters - we
+		 * must first seal the packet, then seal the
+		 * sequence number - this is because 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);
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			return nt_status;
+		}
+
+		arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
+				   data, length);
+		if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
+			arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
+					   sig->data+4, 8);
+		}
+	} else {
+		bool ok;
+		uint32_t crc;
+
+		crc = crc32_calc_buffer(data, length);
+
+		ok = msrpc_gen(sig_mem_ctx,
+			       sig, "dddd",
+			       NTLMSSP_SIGN_VERSION, 0, crc,
+			       ntlmssp_state->crypt->ntlm.seq_num);
+		if (!ok) {
+			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 because the ntlmv1_arc4_state
+		 * is not constant, but is is rather updated with
+		 * each iteration
+		 */
+
+		dump_arc4_state("ntlmv1 arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm.seal_state);
+		arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
+				   data, length);
+
+		dump_arc4_state("ntlmv1 arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm.seal_state);
+
+		arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
+				   sig->data+4, sig->length-4);
+
+		ntlmssp_state->crypt->ntlm.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(struct ntlmssp_state *ntlmssp_state,
+			       uint8_t *data, size_t length,
+			       const uint8_t *whole_pdu, size_t pdu_length,
+			       const DATA_BLOB *sig)
+{
+	NTSTATUS status;
+	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. */
+		arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
+				   data, length);
+		dump_data_pw("ntlmv2 clear data\n", data, length);
+	} else {
+		arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
+				   data, length);
+		dump_data_pw("ntlmv1 clear data\n", data, length);
+	}
+	status = ntlmssp_check_packet(ntlmssp_state,
+				      data, length,
+				      whole_pdu, pdu_length,
+				      sig);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(1,("NTLMSSP packet check for unseal failed due to invalid signature on %llu bytes of input:\n",
+			 (unsigned long long)length));
+	}
+	return status;
+}
+
+/**
+   Initialise the state for NTLMSSP signing.
+*/
+NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
+{
+	DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
+	debug_ntlmssp_flags(ntlmssp_state->neg_flags);
+
+	if (ntlmssp_state->session_key.length < 8) {
+		DEBUG(3, ("NO session key, cannot intialise signing\n"));
+		return NT_STATUS_NO_USER_SESSION_KEY;
+	}
+
+	ntlmssp_state->crypt = talloc_zero(ntlmssp_state,
+					   union ntlmssp_crypt_state);
+	if (ntlmssp_state->crypt == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	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;
+		uint8_t send_seal_key[16];
+		DATA_BLOB send_seal_blob = data_blob_const(send_seal_key,
+					   sizeof(send_seal_key));
+		uint8_t recv_seal_key[16];
+		DATA_BLOB recv_seal_blob = data_blob_const(recv_seal_key,
+					   sizeof(recv_seal_key));
+
+		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.
+		 *
+		 * Key weakening was not performed on the master key
+		 * for NTLM2, but must be done on the encryption subkeys only.
+		 */
+
+		if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
+			/* nothing to do */
+		} 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->crypt->ntlm2.sending.sign_key,
+				ntlmssp_state->session_key, send_sign_const);
+		dump_data_pw("NTLMSSP send sign key:\n",
+			     ntlmssp_state->crypt->ntlm2.sending.sign_key, 16);
+
+		/* SEND: seal ARCFOUR pad */
+		calc_ntlmv2_key(send_seal_key,
+				weak_session_key, send_seal_const);
+		dump_data_pw("NTLMSSP send seal key:\n", send_seal_key, 16);
+
+		arcfour_init(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
+			     &send_seal_blob);
+
+		dump_arc4_state("NTLMSSP send seal arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm2.sending.seal_state);
+
+		/* SEND: seq num */
+		ntlmssp_state->crypt->ntlm2.sending.seq_num = 0;
+
+		/* RECV: sign key */
+		calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.receiving.sign_key,
+				ntlmssp_state->session_key, recv_sign_const);
+		dump_data_pw("NTLMSSP recv sign key:\n",
+			     ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16);
+
+		/* RECV: seal ARCFOUR pad */
+		calc_ntlmv2_key(recv_seal_key,
+				weak_session_key, recv_seal_const);
+		dump_data_pw("NTLMSSP recv seal key:\n", recv_seal_key, 16);
+
+		arcfour_init(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
+			     &recv_seal_blob);
+
+		dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm2.receiving.seal_state);
+
+		/* RECV: seq num */
+		ntlmssp_state->crypt->ntlm2.receiving.seq_num = 0;
+	} else {
+		uint8_t weak_session_key[8];
+		DATA_BLOB seal_session_key = ntlmssp_state->session_key;
+		bool do_weak = false;
+
+		DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
+
+		/*
+		 * 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) {
+			do_weak = true;
+		}
+
+		/*
+		 * Nothing to weaken.
+		 * We certainly don't want to 'extend' the length...
+		 */
+		if (seal_session_key.length < 16) {
+			/* TODO: is this really correct? */
+			do_weak = false;
+		}
+
+		if (do_weak) {
+			memcpy(weak_session_key, seal_session_key.data, 8);
+			seal_session_key = data_blob_const(weak_session_key, 8);
+
+			/*
+			 * 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) {
+				weak_session_key[7] = 0xa0;
+			} else { /* forty bits */
+				weak_session_key[5] = 0xe5;
+				weak_session_key[6] = 0x38;
+				weak_session_key[7] = 0xb0;
+			}
+		}
+
+		arcfour_init(&ntlmssp_state->crypt->ntlm.seal_state,
+			     &seal_session_key);
+
+		dump_arc4_state("NTLMv1 arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm.seal_state);
+
+		ntlmssp_state->crypt->ntlm.seq_num = 0;
+	}
+
+	return NT_STATUS_OK;
+}