IEEEtran.cls

sections/examples.tex

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+%\section{Attacker Model Gadget Examples}%
+%\label{sub:Attacker Model Gadget Examples}
+
+\begin{figure}[h]
+\begin{lstlisting}[caption={Example dropping attacker model gadget with drop limit of 3, targetting channel "cn"}, label={lst:korg_drop}]
+chan cn = [8] of { int, int, int }; 
+
+active proctype attacker_drop() {
+int b_0, b_1, b_2;
+byte lim = 3; // drop limit
+MAIN:
+  do
+  :: cn ? [b_0, b_1, b_2] -> atomic {
+    if
+    :: lim == 0 -> goto BREAK;
+    :: else ->
+       cn ? b_0, b_1, b_2; // consume message on the channel
+       lim = lim - 1;
+       goto MAIN;
+    fi
+    }
+  od
+BREAK:
+}
+\end{lstlisting}
+\end{figure}
+
+\begin{figure}[h]
+\begin{lstlisting}[caption={Example replay attacker model gadget with the selected replay limit as 3, targetting channel "cn"}, label={lst:korg_replay}]
+chan cn = [8] of { int, int, int }; 
+
+// local memory for the gadget
+chan gadget_mem = [3] of { int, int, int };
+
+active proctype attacker_replay() {
+int b_0, b_1, b_2;
+int i = 3;
+CONSUME:
+  do
+  // read messages until the limit is passed
+  :: cn ? [b_0, b_1, b_2] -> atomic {
+   cn ? <b_0, b_1, b_2> -> gadget_mem ! b_0, b_1, b_2;
+    i--;
+    if
+    :: i == 0 -> goto REPLAY;
+    :: i != 0 -> goto CONSUME;
+    fi
+    }
+  od
+REPLAY:
+  do
+  :: atomic {
+    // nondeterministically select a random value from the storage buffer
+    int am;
+    select(am : 0 .. len(gadget_mem)-1);
+    do
+    :: am != 0 ->
+      am = am-1;
+      gadget_mem ? b_0, b_1, b_2 -> gadget_mem ! b_0, b_1, b_2;
+    :: am == 0 ->
+      gadget_mem ? b_0, b_1, b_2 -> cn ! b_0, b_1, b_2;
+      break;
+    od
+    }
+  // doesn't need to use all messages on the channel
+  :: atomic {gadget_mem ? b_0, b_1, b_2; }
+  // once mem has no more messages, we're done
+  :: empty(gadget_mem) -> goto BREAK;
+  od
+BREAK:
+}
+\end{lstlisting}
+\end{figure}
+
+\begin{figure}[h]
+\begin{lstlisting}[caption={Example reordering attacker model gadget with the selected replay limit as 3, targetting channel "cn"}, label={lst:korg_reordering}]
+chan cn = [8] of { int, int, int }; 
+
+chan gadget_mem = [3] of { int, int, int };
+active proctype attacker_reordering() priority 255 {
+byte b_0, b_1, b_2, blocker;
+int i = 3;
+INIT:
+do
+  // arbitrarily choose a message to start consuming on
+  :: {
+      blocker = len(cn);
+      do
+      :: b != len(c) -> goto INIT;
+      od
+    }
+  :: goto CONSUME;
+od
+CONSUME:
+do
+  // consume messages with high priority
+  :: c ? [b_0] -> atomic {
+    c ? b_0 -> gadget_mem ! b_0;
+    i--;
+    if 
+    :: i == 0 -> goto REPLAY;
+    :: i != 0 -> goto CONSUME;
+    fi
+  }
+od
+REPLAY:
+  do
+  // replay messages back onto the channel, also with priority
+  :: atomic {
+    int am;
+    select(am : 0 .. len(gadget_mem)-1);
+    do
+    :: am != 0 ->
+      am = am-1;
+      gadget_mem ? b_0 -> attacker_mem_0 ! b_0;
+    :: am == 0 ->
+      gadget_mem ? b_0 -> c ! b_0;
+      break;
+    od
+    }
+  :: atomic { empty(gadget_mem) -> goto BREAK; }
+  od
+BREAK:
+}
+
+\end{lstlisting}
+\end{figure}
+
+\begin{figure}[h]
+\begin{lstlisting}[caption={Example I/O file targetting channel "cn"}, label={lst:io-file}]
+cn:
+	I:
+	O:1-1-1, 1-2-3, 3-4-5
+\end{lstlisting}
+
+\begin{lstlisting}[caption={Example gadget synthesized from an I/O file targetting the channel "cn"}, label={lst:io-file-synth}]
+chan cn = [8] of { int, int, int };
+
+active proctype daisy() {
+INIT:
+  do
+  :: cn ! 1,1,1;
+  :: cn ! 1,2,3;
+  :: cn ! 3,4,5;
+  :: goto RECOVERY;
+  od
+RECOVERY:
+}
+\end{lstlisting}
+\end{figure}
+