Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 893 insertions, 0 deletions

diff --git a/auth/ntlmssp/ntlmssp_sign.c b/auth/ntlmssp/ntlmssp_sign.c
new file mode 100644
index 0000000..11e5930
--- /dev/null
+++ b/auth/ntlmssp/ntlmssp_sign.c
@@ -0,0 +1,893 @@
+/*
+ *  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 "../auth/ntlmssp/ntlmssp.h"
+#include "../libcli/auth/libcli_auth.h"
+#include "zlib.h"
+#include "../auth/ntlmssp/ntlmssp_private.h"
+
+#include "lib/crypto/gnutls_helpers.h"
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+
+#undef DBGC_CLASS
+#define DBGC_CLASS DBGC_AUTH
+
+#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,
+			    gnutls_cipher_hd_t *state)
+{
+	DBG_DEBUG("%s\n", description);
+}
+
+static NTSTATUS calc_ntlmv2_key(uint8_t subkey[16],
+				DATA_BLOB session_key,
+				const char *constant)
+{
+	gnutls_hash_hd_t hash_hnd = NULL;
+	int rc;
+
+	rc = gnutls_hash_init(&hash_hnd, GNUTLS_DIG_MD5);
+	if (rc < 0) {
+		return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+	}
+	rc = gnutls_hash(hash_hnd, session_key.data, session_key.length);
+	if (rc < 0) {
+		gnutls_hash_deinit(hash_hnd, NULL);
+		return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+	}
+	rc = gnutls_hash(hash_hnd, constant, strlen(constant) + 1);
+	if (rc < 0) {
+		gnutls_hash_deinit(hash_hnd, NULL);
+		return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+	}
+	gnutls_hash_deinit(hash_hnd, subkey);
+
+	return NT_STATUS_OK;
+}
+
+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)
+{
+	NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
+	int rc;
+
+	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
+		gnutls_hmac_hd_t hmac_hnd = NULL;
+		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++;
+
+			rc = gnutls_hmac_init(&hmac_hnd,
+					      GNUTLS_MAC_MD5,
+					      ntlmssp_state->crypt->ntlm2.sending.sign_key,
+					      16);
+			if (rc < 0) {
+				return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+			}
+			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++;
+
+			rc = gnutls_hmac_init(&hmac_hnd,
+					      GNUTLS_MAC_MD5,
+					      ntlmssp_state->crypt->ntlm2.receiving.sign_key,
+					      16);
+			if (rc < 0) {
+				return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+			}
+			break;
+		}
+
+		dump_data_pw("pdu data ", whole_pdu, pdu_length);
+
+		rc = gnutls_hmac(hmac_hnd, seq_num, sizeof(seq_num));
+		if (rc < 0) {
+			gnutls_hmac_deinit(hmac_hnd, NULL);
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+		rc = gnutls_hmac(hmac_hnd, whole_pdu, pdu_length);
+		if (rc < 0) {
+			gnutls_hmac_deinit(hmac_hnd, NULL);
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+		gnutls_hmac_deinit(hmac_hnd, digest);
+
+		if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
+			switch (direction) {
+			case NTLMSSP_SEND:
+				rc = gnutls_cipher_encrypt(ntlmssp_state->crypt->ntlm2.sending.seal_state,
+							   digest,
+							   8);
+				break;
+			case NTLMSSP_RECEIVE:
+				rc = gnutls_cipher_encrypt(ntlmssp_state->crypt->ntlm2.receiving.seal_state,
+							   digest,
+							   8);
+				break;
+			}
+			if (rc < 0) {
+				DBG_ERR("gnutls_cipher_encrypt for NTLMv2 EXCH "
+					"%s packet signature failed: %s\n",
+					direction == NTLMSSP_SEND ?
+						"send" : "receive",
+					gnutls_strerror(rc));
+				return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+			}
+		}
+
+		SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
+		memcpy(sig->data + 4, digest, 8);
+		ZERO_ARRAY(digest);
+		memcpy(sig->data + 12, seq_num, 4);
+		ZERO_ARRAY(seq_num);
+
+		dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
+
+	} else {
+		uint32_t crc;
+
+		crc = crc32(0, Z_NULL, 0);
+		crc = crc32(crc, data, length);
+
+		status = msrpc_gen(sig_mem_ctx,
+			       sig, "dddd",
+			       NTLMSSP_SIGN_VERSION, 0, crc,
+			       ntlmssp_state->crypt->ntlm.seq_num);
+		if (!NT_STATUS_IS_OK(status)) {
+			return status;
+		}
+
+		ntlmssp_state->crypt->ntlm.seq_num++;
+
+		dump_arc4_state("ntlmssp hash: \n",
+				&ntlmssp_state->crypt->ntlm.seal_state);
+		rc = gnutls_cipher_encrypt(ntlmssp_state->crypt->ntlm.seal_state,
+					   sig->data + 4,
+					   sig->length - 4);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_encrypt for NTLM packet "
+				"signature failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+	}
+
+	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 ||
+		    !mem_equal_const_time(local_sig.data, sig->data, sig->length)) {
+			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 ||
+		    !mem_equal_const_time(local_sig.data + 8, sig->data + 8, sig->length - 8)) {
+			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)
+{
+	int rc;
+
+	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->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) {
+		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;
+		}
+
+		rc = gnutls_cipher_encrypt(ntlmssp_state->crypt->ntlm2.sending.seal_state,
+					   data,
+					   length);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_encrypt ntlmv2 sealing the data "
+				"failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+		if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
+			rc = gnutls_cipher_encrypt(ntlmssp_state->crypt->ntlm2.sending.seal_state,
+						    sig->data + 4,
+						    8);
+			if (rc < 0) {
+				DBG_ERR("gnutls_cipher_encrypt ntlmv2 sealing "
+					"the EXCH signature data failed: %s\n",
+					gnutls_strerror(rc));
+				return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+			}
+		}
+	} else {
+		NTSTATUS status;
+		uint32_t crc;
+
+		crc = crc32(0, Z_NULL, 0);
+		crc = crc32(crc, data, length);
+
+		status = msrpc_gen(sig_mem_ctx,
+			       sig, "dddd",
+			       NTLMSSP_SIGN_VERSION, 0, crc,
+			       ntlmssp_state->crypt->ntlm.seq_num);
+		if (!NT_STATUS_IS_OK(status)) {
+			return status;
+		}
+
+		/*
+		 * 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);
+		rc = gnutls_cipher_encrypt(ntlmssp_state->crypt->ntlm.seal_state,
+					   data,
+					   length);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_encrypt ntlmv1 sealing data"
+				"failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+
+		dump_arc4_state("ntlmv1 arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm.seal_state);
+
+		rc = gnutls_cipher_encrypt(ntlmssp_state->crypt->ntlm.seal_state,
+					    sig->data + 4,
+					    sig->length - 4);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_encrypt ntlmv1 sealing signing "
+				"data failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+
+		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;
+	int rc;
+
+	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. */
+		rc = gnutls_cipher_decrypt(ntlmssp_state->crypt->ntlm2.receiving.seal_state,
+					   data,
+					   length);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_decrypt ntlmv2 unsealing the "
+				"data failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+		dump_data_pw("ntlmv2 clear data\n", data, length);
+	} else {
+		rc = gnutls_cipher_decrypt(ntlmssp_state->crypt->ntlm.seal_state,
+					   data,
+					   length);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_decrypt ntlmv1 unsealing the "
+				"data failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+		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;
+}
+
+NTSTATUS ntlmssp_wrap(struct ntlmssp_state *ntlmssp_state,
+		      TALLOC_CTX *out_mem_ctx,
+		      const DATA_BLOB *in,
+		      DATA_BLOB *out)
+{
+	NTSTATUS nt_status;
+	DATA_BLOB sig;
+
+	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) {
+		if (in->length + NTLMSSP_SIG_SIZE < in->length) {
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+
+		*out = data_blob_talloc(out_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
+		if (!out->data) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
+
+	        nt_status = ntlmssp_seal_packet(ntlmssp_state, out_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);
+			talloc_free(sig.data);
+		}
+		return nt_status;
+
+	} else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) {
+		if (in->length + NTLMSSP_SIG_SIZE < in->length) {
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+
+		*out = data_blob_talloc(out_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
+		if (!out->data) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
+
+	        nt_status = ntlmssp_sign_packet(ntlmssp_state, out_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);
+			talloc_free(sig.data);
+		}
+		return nt_status;
+	} else {
+		*out = data_blob_talloc(out_mem_ctx, in->data, in->length);
+		if (!out->data) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		return NT_STATUS_OK;
+	}
+}
+
+NTSTATUS ntlmssp_unwrap(struct ntlmssp_state *ntlmssp_state,
+			TALLOC_CTX *out_mem_ctx,
+			const DATA_BLOB *in,
+			DATA_BLOB *out)
+{
+	DATA_BLOB sig;
+
+	if (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(out_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
+
+	        return ntlmssp_unseal_packet(ntlmssp_state,
+					     out->data, out->length,
+					     out->data, out->length,
+					     &sig);
+
+	} else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_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(out_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
+
+		return ntlmssp_check_packet(ntlmssp_state,
+					    out->data, out->length,
+					    out->data, out->length,
+					    &sig);
+	} else {
+		*out = data_blob_talloc(out_mem_ctx, in->data, in->length);
+		if (!out->data) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		return NT_STATUS_OK;
+	}
+}
+
+/**
+   Initialise the state for NTLMSSP signing.
+*/
+NTSTATUS ntlmssp_sign_reset(struct ntlmssp_state *ntlmssp_state,
+			    bool reset_seqnums)
+{
+	int rc;
+
+	DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
+	debug_ntlmssp_flags(ntlmssp_state->neg_flags);
+
+	if (ntlmssp_state->crypt == NULL) {
+		return NT_STATUS_INVALID_PARAMETER_MIX;
+	}
+
+	if (ntlmssp_state->force_wrap_seal &&
+	    (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN))
+	{
+		/*
+		 * We need to handle NTLMSSP_NEGOTIATE_SIGN as
+		 * NTLMSSP_NEGOTIATE_SEAL if GENSEC_FEATURE_LDAP_STYLE
+		 * is requested.
+		 *
+		 * The negotiation of flags (and authentication)
+		 * is completed when ntlmssp_sign_init() is called
+		 * so we can safely pretent NTLMSSP_NEGOTIATE_SEAL
+		 * was negotiated.
+		 */
+		ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL;
+	}
+
+	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] = {0};
+		gnutls_datum_t send_seal_blob = {
+			.data = send_seal_key,
+			.size = sizeof(send_seal_key),
+		};
+		uint8_t recv_seal_key[16] = {0};
+		gnutls_datum_t recv_seal_blob = {
+			.data = recv_seal_key,
+			.size = sizeof(recv_seal_key),
+		};
+		NTSTATUS status;
+
+		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 */
+		status = calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.sending.sign_key,
+					 ntlmssp_state->session_key, send_sign_const);
+		if (!NT_STATUS_IS_OK(status)) {
+			return status;
+		}
+		dump_data_pw("NTLMSSP send sign key:\n",
+			     ntlmssp_state->crypt->ntlm2.sending.sign_key, 16);
+
+		/* SEND: seal ARCFOUR pad */
+		status = calc_ntlmv2_key(send_seal_key,
+					 weak_session_key,
+					 send_seal_const);
+		if (!NT_STATUS_IS_OK(status)) {
+			return status;
+		}
+		dump_data_pw("NTLMSSP send seal key:\n",
+			     send_seal_key,
+			     sizeof(send_seal_key));
+
+		if (ntlmssp_state->crypt->ntlm2.sending.seal_state != NULL) {
+			gnutls_cipher_deinit(ntlmssp_state->crypt->ntlm2.sending.seal_state);
+		}
+		rc = gnutls_cipher_init(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
+					GNUTLS_CIPHER_ARCFOUR_128,
+					&send_seal_blob,
+					NULL);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_init failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+
+		dump_arc4_state("NTLMSSP send seal arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm2.sending.seal_state);
+
+		/* SEND: seq num */
+		if (reset_seqnums) {
+			ntlmssp_state->crypt->ntlm2.sending.seq_num = 0;
+		}
+
+		/* RECV: sign key */
+		status = calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.receiving.sign_key,
+					 ntlmssp_state->session_key, recv_sign_const);
+		if (!NT_STATUS_IS_OK(status)) {
+			return status;
+		}
+		dump_data_pw("NTLMSSP recv sign key:\n",
+			     ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16);
+
+		/* RECV: seal ARCFOUR pad */
+		status = calc_ntlmv2_key(recv_seal_key,
+					 weak_session_key,
+					 recv_seal_const);
+		if (!NT_STATUS_IS_OK(status)) {
+			return status;
+		}
+		dump_data_pw("NTLMSSP recv seal key:\n",
+			     recv_seal_key,
+			     sizeof(recv_seal_key));
+
+		if (ntlmssp_state->crypt->ntlm2.receiving.seal_state != NULL) {
+			gnutls_cipher_deinit(ntlmssp_state->crypt->ntlm2.receiving.seal_state);
+		}
+		rc = gnutls_cipher_init(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
+					GNUTLS_CIPHER_ARCFOUR_128,
+					&recv_seal_blob,
+					NULL);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_init failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+
+		dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm2.receiving.seal_state);
+
+		/* RECV: seq num */
+		if (reset_seqnums) {
+			ntlmssp_state->crypt->ntlm2.receiving.seq_num = 0;
+		}
+	} else {
+		gnutls_datum_t seal_session_key = {
+			.data = ntlmssp_state->session_key.data,
+			.size = ntlmssp_state->session_key.length,
+		};
+		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 (ntlmssp_state->session_key.length < 16) {
+			/* TODO: is this really correct? */
+			do_weak = false;
+		}
+
+		if (do_weak) {
+			uint8_t weak_session_key[8];
+
+			memcpy(weak_session_key, seal_session_key.data, 8);
+			seal_session_key = (gnutls_datum_t) {
+				.data = weak_session_key,
+				.size = sizeof(weak_session_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) {
+				weak_session_key[7] = 0xa0;
+			} else { /* forty bits */
+				weak_session_key[5] = 0xe5;
+				weak_session_key[6] = 0x38;
+				weak_session_key[7] = 0xb0;
+			}
+		}
+
+		if (ntlmssp_state->crypt->ntlm.seal_state != NULL) {
+			gnutls_cipher_deinit(ntlmssp_state->crypt->ntlm.seal_state);
+		}
+		rc = gnutls_cipher_init(&ntlmssp_state->crypt->ntlm.seal_state,
+					GNUTLS_CIPHER_ARCFOUR_128,
+					&seal_session_key,
+					NULL);
+		if (rc < 0) {
+			DBG_ERR("gnutls_cipher_init failed: %s\n",
+				gnutls_strerror(rc));
+			return gnutls_error_to_ntstatus(rc, NT_STATUS_NTLM_BLOCKED);
+		}
+
+		dump_arc4_state("NTLMv1 arc4 state:\n",
+				&ntlmssp_state->crypt->ntlm.seal_state);
+
+		if (reset_seqnums) {
+			ntlmssp_state->crypt->ntlm.seq_num = 0;
+		}
+	}
+
+	return NT_STATUS_OK;
+}
+
+static int ntlmssp_crypt_free_gnutls_cipher_state(union ntlmssp_crypt_state *c)
+{
+	if (c->ntlm2.sending.seal_state != NULL) {
+		gnutls_cipher_deinit(c->ntlm2.sending.seal_state);
+		c->ntlm2.sending.seal_state = NULL;
+	}
+	if (c->ntlm2.receiving.seal_state != NULL) {
+		gnutls_cipher_deinit(c->ntlm2.receiving.seal_state);
+		c->ntlm2.receiving.seal_state = NULL;
+	}
+	if (c->ntlm.seal_state != NULL) {
+		gnutls_cipher_deinit(c->ntlm.seal_state);
+		c->ntlm.seal_state = NULL;
+	}
+
+	return 0;
+}
+
+NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
+{
+	if (ntlmssp_state->session_key.length < 8) {
+		DEBUG(3, ("NO session key, cannot initialise 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;
+	}
+	talloc_set_destructor(ntlmssp_state->crypt,
+			      ntlmssp_crypt_free_gnutls_cipher_state);
+
+	return ntlmssp_sign_reset(ntlmssp_state, true);
+}