--- backend/dell1600n_net.c.orig	2013-02-23 03:00:56.000000000 +0100
+++ backend/dell1600n_net.c	2015-10-06 10:44:01.000000000 +0200
@@ -943,7 +943,7 @@ HexDump (int debugLevel, const unsigned
 
       sprintf (itemBuf, "%02x ", (const unsigned int) buf[i]);
 
-      strncat (lineBuf, itemBuf, sizeof (lineBuf));
+      strncat (lineBuf, itemBuf, sizeof (lineBuf) - strlen (lineBuf) - 1);
 
       if ((i + 1) % 16)
         continue;
@@ -960,7 +960,7 @@ HexDump (int debugLevel, const unsigned
         {
           sprintf (itemBuf, ".");
         }
-    strncat (lineBuf, itemBuf, sizeof (lineBuf));
+    strncat (lineBuf, itemBuf, sizeof (lineBuf) - strlen (lineBuf) - 1);
 
     } /* for j */
 
@@ -974,7 +974,7 @@ HexDump (int debugLevel, const unsigned
 
       for (j = (i % 16); j < 16; ++j)
         {
-          strncat (lineBuf, "   ", sizeof (lineBuf));
+          strncat (lineBuf, "   ", sizeof (lineBuf) - strlen (lineBuf) - 1);
         }
       for (j = 1 + i - ((i + 1) % 16); j < i; ++j)
         {
@@ -986,7 +986,7 @@ HexDump (int debugLevel, const unsigned
             {
               strcpy (itemBuf, ".");
             }
-          strncat (lineBuf, itemBuf, sizeof (lineBuf));
+          strncat (lineBuf, itemBuf, sizeof (lineBuf) - strlen (lineBuf) - 1);
         }
       DBG (debugLevel, "%s\n", lineBuf);
     }