1 files changed, 290 insertions, 0 deletions
diff --git a/source3/smbd/smb1_signing.c b/source3/smbd/smb1_signing.c
new file mode 100644
index 0000000..aa3027d
--- /dev/null
+++ b/source3/smbd/smb1_signing.c
@@ -0,0 +1,290 @@
+/*
+   Unix SMB/CIFS implementation.
+   SMB Signing Code
+   Copyright (C) Jeremy Allison 2003.
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
+   Copyright (C) Stefan Metzmacher 2009
+
+   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 "smbd/smbd.h"
+#include "smbd/globals.h"
+#include "../libcli/smb/smb_signing.h"
+#include "lib/param/param.h"
+
+/***********************************************************
+ Called to validate an incoming packet from the client.
+************************************************************/
+
+bool smb1_srv_check_sign_mac(struct smbXsrv_connection *conn,
+			const char *inbuf, uint32_t *seqnum,
+			bool trusted_channel)
+{
+	const uint8_t *inhdr;
+	size_t len;
+
+	/* Check if it's a non-session message. */
+	if(CVAL(inbuf,0)) {
+		return true;
+	}
+
+	len = smb_len(inbuf);
+	inhdr = (const uint8_t *)inbuf + NBT_HDR_SIZE;
+
+	if (trusted_channel) {
+		NTSTATUS status;
+
+		if (len < (HDR_SS_FIELD + 8)) {
+			DBG_WARNING("Can't check signature "
+				 "on short packet! smb_len = %u\n",
+				 (unsigned)len);
+			return false;
+		}
+
+		status = NT_STATUS(IVAL(inhdr, HDR_SS_FIELD + 4));
+		if (!NT_STATUS_IS_OK(status)) {
+			DBG_WARNING("trusted channel passed %s\n",
+				 nt_errstr(status));
+			return false;
+		}
+
+		*seqnum = IVAL(inhdr, HDR_SS_FIELD);
+		return true;
+	}
+
+	*seqnum = smb1_signing_next_seqnum(conn->smb1.signing_state, false);
+	return smb1_signing_check_pdu(conn->smb1.signing_state,
+				     inhdr, len,
+				     *seqnum);
+}
+
+/***********************************************************
+ Called to sign an outgoing packet to the client.
+************************************************************/
+
+NTSTATUS smb1_srv_calculate_sign_mac(struct smbXsrv_connection *conn,
+				char *outbuf, uint32_t seqnum)
+{
+	uint8_t *outhdr;
+	size_t len;
+
+	/* Check if it's a non-session message. */
+	if(CVAL(outbuf,0)) {
+		return NT_STATUS_OK;;
+	}
+
+	len = smb_len(outbuf);
+	outhdr = (uint8_t *)outbuf + NBT_HDR_SIZE;
+
+	return smb1_signing_sign_pdu(conn->smb1.signing_state,
+				    outhdr,
+				    len,
+				    seqnum);
+}
+
+
+/***********************************************************
+ Called to indicate a oneway request
+************************************************************/
+void smb1_srv_cancel_sign_response(struct smbXsrv_connection *conn)
+{
+	smb1_signing_cancel_reply(conn->smb1.signing_state, true);
+}
+
+struct smbd_shm_signing {
+	size_t shm_size;
+	uint8_t *shm_pointer;
+
+	/* we know the signing engine will only allocate 2 chunks */
+	uint8_t *ptr1;
+	size_t len1;
+	uint8_t *ptr2;
+	size_t len2;
+};
+
+static int smbd_shm_signing_destructor(struct smbd_shm_signing *s)
+{
+	anonymous_shared_free(s->shm_pointer);
+	return 0;
+}
+
+static void *smbd_shm_signing_alloc(TALLOC_CTX *mem_ctx, size_t len)
+{
+	struct smbd_shm_signing *s = talloc_get_type_abort(mem_ctx,
+				     struct smbd_shm_signing);
+
+	if (s->ptr1 == NULL) {
+		s->len1 = len;
+		if (len % 8) {
+			s->len1 += (8 - (len % 8));
+		}
+		if (s->len1 > s->shm_size) {
+			s->len1 = 0;
+			errno = ENOMEM;
+			return NULL;
+		}
+		s->ptr1 = s->shm_pointer;
+		return s->ptr1;
+	}
+
+	if (s->ptr2 == NULL) {
+		s->len2 = len;
+		if (s->len2 > (s->shm_size - s->len1)) {
+			s->len2 = 0;
+			errno = ENOMEM;
+			return NULL;
+		}
+		s->ptr2 = s->shm_pointer + s->len1;
+		return s->ptr2;
+	}
+
+	errno = ENOMEM;
+	return NULL;
+}
+
+static void smbd_shm_signing_free(TALLOC_CTX *mem_ctx, void *ptr)
+{
+	struct smbd_shm_signing *s = talloc_get_type_abort(mem_ctx,
+				     struct smbd_shm_signing);
+
+	if (s->ptr2 == ptr) {
+		s->ptr2 = NULL;
+		s->len2 = 0;
+	}
+}
+
+/***********************************************************
+ Called by server negprot when signing has been negotiated.
+************************************************************/
+
+bool smb1_srv_init_signing(struct loadparm_context *lp_ctx,
+			   struct smbXsrv_connection *conn)
+{
+	bool allowed = true;
+	bool desired;
+	bool mandatory = false;
+
+	/*
+	 * if the client and server allow signing,
+	 * we desire to use it.
+	 *
+	 * This matches Windows behavior and is needed
+	 * because not every client that requires signing
+	 * sends FLAGS2_SMB_SECURITY_SIGNATURES_REQUIRED.
+	 *
+	 * Note that we'll always allow signing if the client
+	 * does send FLAGS2_SMB_SECURITY_SIGNATURES_REQUIRED.
+	 */
+
+	desired = lpcfg_server_signing_allowed(lp_ctx, &mandatory);
+
+	if (lp_async_smb_echo_handler()) {
+		struct smbd_shm_signing *s;
+
+		/* setup the signing state in shared memory */
+		s = talloc_zero(conn, struct smbd_shm_signing);
+		if (s == NULL) {
+			return false;
+		}
+		s->shm_size = 4096;
+		s->shm_pointer =
+			(uint8_t *)anonymous_shared_allocate(s->shm_size);
+		if (s->shm_pointer == NULL) {
+			talloc_free(s);
+			return false;
+		}
+		talloc_set_destructor(s, smbd_shm_signing_destructor);
+		conn->smb1.signing_state = smb1_signing_init_ex(s,
+							allowed, desired, mandatory,
+							smbd_shm_signing_alloc,
+							smbd_shm_signing_free);
+		if (!conn->smb1.signing_state) {
+			return false;
+		}
+		return true;
+	}
+
+	conn->smb1.signing_state = smb1_signing_init(conn,
+						    allowed, desired, mandatory);
+	if (!conn->smb1.signing_state) {
+		return false;
+	}
+
+	return true;
+}
+
+void smb1_srv_set_signing_negotiated(struct smbXsrv_connection *conn,
+				bool allowed, bool mandatory)
+{
+	smb1_signing_set_negotiated(conn->smb1.signing_state,
+				   allowed, mandatory);
+}
+
+/***********************************************************
+ Returns whether signing is active. We can't use sendfile or raw
+ reads/writes if it is.
+************************************************************/
+
+bool smb1_srv_is_signing_active(struct smbXsrv_connection *conn)
+{
+	return smb1_signing_is_active(conn->smb1.signing_state);
+}
+
+
+/***********************************************************
+ Returns whether signing is negotiated. We can't use it unless it was
+ in the negprot.
+************************************************************/
+
+bool smb1_srv_is_signing_negotiated(struct smbXsrv_connection *conn)
+{
+	return smb1_signing_is_negotiated(conn->smb1.signing_state);
+}
+
+/***********************************************************
+ Turn on signing from this packet onwards.
+************************************************************/
+
+void smb1_srv_set_signing(struct smbXsrv_connection *conn,
+		     const DATA_BLOB user_session_key,
+		     const DATA_BLOB response)
+{
+	bool negotiated;
+	bool mandatory;
+
+	if (!user_session_key.length)
+		return;
+
+	negotiated = smb1_signing_is_negotiated(conn->smb1.signing_state);
+	mandatory = smb1_signing_is_mandatory(conn->smb1.signing_state);
+
+	if (!negotiated && !mandatory) {
+		DBG_INFO("signing negotiated = %u, "
+			 "mandatory_signing = %u. Not allowing smb signing.\n",
+			 negotiated, mandatory);
+		return;
+	}
+
+	if (!smb1_signing_activate(conn->smb1.signing_state,
+				  user_session_key, response)) {
+		return;
+	}
+
+	DBG_NOTICE("turning on SMB signing: "
+		 "signing negotiated = %u, mandatory_signing = %u.\n",
+		 negotiated, mandatory);
+}
+