--- samba-3.0.23c.orig/source/libsmb/smb_signing.c	2006-10-13 14:50:07.000000000 -0700
+++ samba-3.0.23c/source/libsmb/smb_signing.c	2006-10-20 17:55:00.000000000 -0700
@@ -609,9 +609,16 @@
 	struct smb_sign_info *si = &cli->sign_info;
 	struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context;
 
+	DEBUG(10, ("client_set_trans_sign_state_on(): entering, cli=%p, mid=%d, data=%p\n", cli, mid, data));
+	
 	if (!si->doing_signing) {
 		return True;
 	}
+	
+	if(!data) {
+		DEBUG(10, ("client_set_trans_sign_state_on(): data NULL, return false\n"));
+		return False;
+	}
 
 	if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, False)) {
 		return False;
@@ -633,7 +640,12 @@
 	if (!si->doing_signing) {
 		return True;
 	}
-
+	
+	if(!data) {
+		DEBUG(10, ("client_set_trans_sign_state_off(): data NULL, return false\n"));
+		return False;
+	}
+	
 	if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, True)) {
 		return False;
 	}