diff --git a/plugins/opcua/opcua.c b/plugins/opcua/opcua.c
index 3200204087..0b1a89f421 100644
--- a/plugins/opcua/opcua.c
+++ b/plugins/opcua/opcua.c
@@ -167,32 +167,32 @@ static void dissect_opcua_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree
     col_set_str(pinfo->cinfo, COL_PROTOCOL, "OpcUa");
 
     /* parse message type */
-    if (tvb->real_data[0] == 'H' && tvb->real_data[1] == 'E' && tvb->real_data[2] == 'L')
+    if (tvb_memeql(tvb, 0, "HEL", 3))
     {
         msgtype = MSG_HELLO;
         pfctParse = parseHello;
     }
-    else if (tvb->real_data[0] == 'A' && tvb->real_data[1] == 'C' && tvb->real_data[2] == 'K')
+    else if (tvb_memeql(tvb, 0, "ACK", 3))
     {
         msgtype = MSG_ACKNOWLEDGE;
         pfctParse = parseAcknowledge;
     }
-    else if (tvb->real_data[0] == 'E' && tvb->real_data[1] == 'R' && tvb->real_data[2] == 'R')
+    else if (tvb_memeql(tvb, 0, "ERR", 3))
     {
         msgtype = MSG_ERROR;
         pfctParse = parseError;
     }
-    else if (tvb->real_data[0] == 'M' && tvb->real_data[1] == 'S' && tvb->real_data[2] == 'G')
+    else if (tvb_memeql(tvb, 0, "MSG", 3))
     {
         msgtype = MSG_MESSAGE;
         pfctParse = parseMessage;
     }
-    else if (tvb->real_data[0] == 'O' && tvb->real_data[1] == 'P' && tvb->real_data[2] == 'N')
+    else if (tvb_memeql(tvb, 0, "OPN", 3))
     {
         msgtype = MSG_OPENSECURECHANNEL;
         pfctParse = parseOpenSecureChannel;
     }
-    else if (tvb->real_data[0] == 'C' && tvb->real_data[1] == 'L' && tvb->real_data[2] == 'O')
+    else if (tvb_memeql(tvb, 0, "CLO", 3))
     {
         msgtype = MSG_CLOSESECURECHANNEL;
         pfctParse = parseCloseSecureChannel;
diff --git a/plugins/opcua/opcua_simpletypes.c b/plugins/opcua/opcua_simpletypes.c
index 777a842e8c..45a7a10640 100644
--- a/plugins/opcua/opcua_simpletypes.c
+++ b/plugins/opcua/opcua_simpletypes.c
@@ -34,9 +34,6 @@
 #include <string.h>
 #include <epan/emem.h>
 
-/* string buffer */
-#define MAX_BUFFER 256
-
 #define DIAGNOSTICINFO_ENCODINGMASK_SYMBOLICID_FLAG           0x01
 #define DIAGNOSTICINFO_ENCODINGMASK_NAMESPACE_FLAG            0x02
 #define DIAGNOSTICINFO_ENCODINGMASK_LOCALIZEDTEXT_FLAG        0x04
@@ -56,6 +53,9 @@
 #define EXTOBJ_ENCODINGMASK_BINBODY_FLAG                      0x01
 #define EXTOBJ_ENCODINGMASK_XMLBODY_FLAG                      0x02
 
+/* Chosen arbitrarily */
+#define MAX_ARRAY_LEN 10000
+
 static int hf_opcua_diag_mask_symbolicflag = -1;
 static int hf_opcua_diag_mask_namespaceflag = -1;
 static int hf_opcua_diag_mask_localizedtextflag = -1;
@@ -338,35 +338,28 @@ void parseInt64(proto_tree *tree, tvbuff_t *tvb, gint *pOffset, int hfIndex)
 
 void parseString(proto_tree *tree, tvbuff_t *tvb, gint *pOffset, int hfIndex)
 {
-    char *szValue = ep_alloc(MAX_BUFFER);
+    char *szValue;
     gint iOffset = *pOffset;
     gint32 iLen = tvb_get_letohl(tvb, *pOffset);
     iOffset+=4;
 
-    if (szValue)
+    if (iLen == -1)
     {
-        if (iLen == -1)
-        {
-            g_snprintf(szValue, MAX_BUFFER, "[OpcUa Null String]");
-        }
-        else if (iLen >= 0)
-        {
-            int iStrLen = iLen;
-            if (iStrLen > (MAX_BUFFER-1)) iStrLen = MAX_BUFFER - 1;
-            /* copy non null terminated string of length iStrlen */
-            strncpy(szValue, (char*)&tvb->real_data[iOffset], iStrLen);
-            /* set null terminator */
-            szValue[iStrLen] = 0;
-            iOffset += iLen; /* eat the whole string */
-        }
-        else
-        {
-            g_snprintf(szValue, MAX_BUFFER, "[Invalid String] Ups, something is wrong with this message.");
-        }
-
-        proto_tree_add_string(tree, hfIndex, tvb, *pOffset, (iOffset - *pOffset), szValue);
-        *pOffset = iOffset;
+        proto_tree_add_string(tree, hfIndex, tvb, *pOffset, (iOffset - *pOffset),
+                              "[OpcUa Null String]");
     }
+    else if (iLen >= 0)
+    {
+        iOffset += iLen; /* eat the whole string */
+        proto_tree_add_item(tree, hfIndex, tvb, *pOffset, (iOffset - *pOffset), TRUE);
+    }
+    else
+    {
+        szValue = ep_strdup_printf("[Invalid String] Invalid length: %d", iLen);
+        proto_tree_add_string(tree, hfIndex, tvb, *pOffset, (iOffset - *pOffset), szValue);
+    }
+
+    *pOffset = iOffset;
 }
 
 void parseStatusCode(proto_tree *tree, tvbuff_t *tvb, gint *pOffset, int hfIndex)
@@ -644,9 +637,17 @@ void parseVariant(proto_tree *tree, tvbuff_t *tvb, gint *pOffset, char *szFieldN
         proto_tree *subtree = proto_item_add_subtree(ti, ett_opcua_array);
         int i;
 
-        for (i=0; i<ArrayLength; i++)
+        if (ArrayLength < MAX_ARRAY_LEN)
         {
-            parseInt32(subtree, tvb, pOffset, hf_opcua_Int32);
+            for (i=0; i<ArrayLength; i++)
+            {
+                parseInt32(subtree, tvb, pOffset, hf_opcua_Int32);
+            }
+        }
+        else
+        {
+            /* XXX - This should be expert_add_info_format, but we need pinfo for that */
+            PROTO_ITEM_SET_GENERATED(proto_tree_add_text(tree, tvb, iOffset, 4, "Array length %d too large to process", ArrayLength));
         }
     }
 
@@ -668,11 +669,17 @@ void parseArraySimple(proto_tree *tree, tvbuff_t *tvb, gint *pOffset, int hfInde
     /* read array length */
     iLen = tvb_get_letohl(tvb, *pOffset);
     proto_tree_add_item(subtree, hf_opcua_ArraySize, tvb, *pOffset, 4, TRUE);
-    *pOffset += 4;
 
     if (iLen == -1) return; /* no array */
     if (iLen == 0)  return; /* array with zero elements*/
 
+    if (iLen > MAX_ARRAY_LEN)
+    {
+        PROTO_ITEM_SET_GENERATED(proto_tree_add_text(tree, tvb, *pOffset, 4, "Array length %d too large to process", iLen));
+        return;
+    }
+
+    *pOffset += 4;
     for (i=0; i<iLen; i++)
     {
         (*pParserFunction)(subtree, tvb, pOffset, hfIndex);
@@ -694,11 +701,17 @@ void parseArrayEnum(proto_tree *tree, tvbuff_t *tvb, gint *pOffset, fctEnumParse
     /* read array length */
     iLen = tvb_get_letohl(tvb, *pOffset);
     proto_tree_add_item(subtree, hf_opcua_ArraySize, tvb, *pOffset, 4, TRUE);
-    *pOffset += 4;
 
     if (iLen == -1) return; /* no array */
     if (iLen == 0)  return; /* array with zero elements*/
 
+    if (iLen > MAX_ARRAY_LEN)
+    {
+        PROTO_ITEM_SET_GENERATED(proto_tree_add_text(tree, tvb, *pOffset, 4, "Array length %d too large to process", iLen));
+        return;
+    }
+
+    *pOffset += 4;
     for (i=0; i<iLen; i++)
     {
         (*pParserFunction)(subtree, tvb, pOffset);
@@ -719,11 +732,17 @@ void parseArrayComplex(proto_tree *tree, tvbuff_t *tvb, gint *pOffset, char *szF
     /* read array length */
     iLen = tvb_get_letohl(tvb, *pOffset);
     proto_tree_add_item(subtree, hf_opcua_ArraySize, tvb, *pOffset, 4, TRUE);
-    *pOffset += 4;
 
     if (iLen == -1) return; /* no array */
     if (iLen == 0)  return; /* array with zero elements*/
 
+    if (iLen > MAX_ARRAY_LEN)
+    {
+        PROTO_ITEM_SET_GENERATED(proto_tree_add_text(tree, tvb, *pOffset, 4, "Array length %d too large to process", iLen));
+        return;
+    }
+
+    *pOffset += 4;
     for (i=0; i<iLen; i++)
     {
         char szNum[20];
diff --git a/plugins/opcua/opcua_transport_layer.c b/plugins/opcua/opcua_transport_layer.c
index bc9e05be4d..8edd1059c9 100644
--- a/plugins/opcua/opcua_transport_layer.c
+++ b/plugins/opcua/opcua_transport_layer.c
@@ -126,35 +126,11 @@ void registerTransportLayerTypes(int proto)
     proto_register_field_array(proto, hf, array_length(hf));
 }
 
-/** helper functions for adding strings,
-  * that are not zero terminated.
-  */
-void addString(proto_tree *tree,  
-               int  hfindex,  
-               tvbuff_t *tvb,  
-               gint  start,  
-               gint  length,  
-               const char *value)
-{
-    char *szValue = ep_alloc(256);
-
-    if (szValue)
-    {
-        if (length > 255) length = 255;
-        /* copy non null terminated string data */
-        strncpy(szValue, value, length);
-        /* set null terminator */
-        szValue[length] = 0;
-
-        proto_tree_add_string(tree, hfindex, tvb, start, length, szValue);
-    }
-}
-
 /* Transport Layer: message parsers */
 void parseHello(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
 {
-    addString(tree, hf_opcua_transport_type, tvb, *pOffset, 3, tvb->real_data); *pOffset+=3;
-    addString(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, &tvb->real_data[*pOffset]); *pOffset+=1;
+    proto_tree_add_item(tree, hf_opcua_transport_type, tvb, *pOffset, 3, TRUE); *pOffset+=3;
+    proto_tree_add_item(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, TRUE); *pOffset+=1;
     proto_tree_add_item(tree, hf_opcua_transport_size, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     proto_tree_add_item(tree, hf_opcua_transport_ver, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     proto_tree_add_item(tree, hf_opcua_transport_rbs, tvb, *pOffset, 4, TRUE); *pOffset+=4;
@@ -166,8 +142,8 @@ void parseHello(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
 
 void parseAcknowledge(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
 {
-    addString(tree, hf_opcua_transport_type, tvb, *pOffset, 3, tvb->real_data); *pOffset+=3;
-    addString(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, &tvb->real_data[*pOffset]); *pOffset+=1;
+    proto_tree_add_item(tree, hf_opcua_transport_type, tvb, *pOffset, 3, TRUE); *pOffset+=3;
+    proto_tree_add_item(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, TRUE); *pOffset+=1;
     proto_tree_add_item(tree, hf_opcua_transport_size, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     proto_tree_add_item(tree, hf_opcua_transport_ver, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     proto_tree_add_item(tree, hf_opcua_transport_rbs, tvb, *pOffset, 4, TRUE); *pOffset+=4;
@@ -178,8 +154,8 @@ void parseAcknowledge(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
 
 void parseError(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
 {
-    addString(tree, hf_opcua_transport_type, tvb, *pOffset, 3, tvb->real_data); *pOffset+=3;
-    addString(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, &tvb->real_data[*pOffset]); *pOffset+=1;
+    proto_tree_add_item(tree, hf_opcua_transport_type, tvb, *pOffset, 3, TRUE); *pOffset+=3;
+    proto_tree_add_item(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, TRUE); *pOffset+=1;
     proto_tree_add_item(tree, hf_opcua_transport_size, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     proto_tree_add_item(tree, hf_opcua_transport_error, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     parseString(tree, tvb, pOffset, hf_opcua_transport_reason);
@@ -192,8 +168,8 @@ void parseMessage(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
     proto_tree *nodeid_tree;
     int ServiceId = 0;
 
-    addString(tree, hf_opcua_transport_type, tvb, *pOffset, 3, tvb->real_data); *pOffset+=3;
-    addString(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, &tvb->real_data[*pOffset]); *pOffset+=1;
+    proto_tree_add_item(tree, hf_opcua_transport_type, tvb, *pOffset, 3, TRUE); *pOffset+=3;
+    proto_tree_add_item(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, TRUE); *pOffset+=1;
     proto_tree_add_item(tree, hf_opcua_transport_size, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     proto_tree_add_item(tree, hf_opcua_transport_scid, tvb, *pOffset, 4, TRUE); *pOffset+=4;
 
@@ -223,8 +199,8 @@ void parseOpenSecureChannel(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
     proto_tree *nodeid_tree;
     int ServiceId = 0;
     
-    addString(tree, hf_opcua_transport_type, tvb, *pOffset, 3, tvb->real_data); *pOffset+=3;
-    addString(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, &tvb->real_data[*pOffset]); *pOffset+=1;
+    proto_tree_add_item(tree, hf_opcua_transport_type, tvb, *pOffset, 3, TRUE); *pOffset+=3;
+    proto_tree_add_item(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, TRUE); *pOffset+=1;
     proto_tree_add_item(tree, hf_opcua_transport_size, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     proto_tree_add_item(tree, hf_opcua_transport_scid, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     parseString(tree, tvb, pOffset, hf_opcua_transport_spu);
@@ -247,8 +223,8 @@ void parseOpenSecureChannel(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
 
 void parseCloseSecureChannel(proto_tree *tree, tvbuff_t *tvb, gint *pOffset)
 {
-    addString(tree, hf_opcua_transport_type, tvb, *pOffset, 3, tvb->real_data); *pOffset+=3;
-    addString(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, &tvb->real_data[*pOffset]); *pOffset+=1;
+    proto_tree_add_item(tree, hf_opcua_transport_type, tvb, *pOffset, 3, TRUE); *pOffset+=3;
+    proto_tree_add_item(tree, hf_opcua_transport_chunk, tvb, *pOffset, 1, TRUE); *pOffset+=1;
     proto_tree_add_item(tree, hf_opcua_transport_size, tvb, *pOffset, 4, TRUE); *pOffset+=4;
     proto_tree_add_item(tree, hf_opcua_transport_scid, tvb, *pOffset, 4, TRUE); *pOffset+=4;
 }