94 lines
2.6 KiB
C
94 lines
2.6 KiB
C
/*
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* Scyther : An automatic verifier for security protocols.
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* Copyright (C) 2007 Cas Cremers
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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/**
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*
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*@file cost.c
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*
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* Determine cost of a given semitrace in sys
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* Constructed for Arachne results, unreliable otherwise.
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*
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*/
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#include "switches.h"
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#include "system.h"
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#include "binding.h"
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#include "error.h"
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#include <limits.h>
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//************************************************************************
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// Private methods
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//************************************************************************
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//************************************************************************
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// Public methods
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//************************************************************************
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//! Determine cost of an attack
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/*
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* This should also work on uncompleted semitraces, and should be monotonous
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* (i.e. further iterations should increase the cost only) so that it can be
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* used for branch and bound.
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*
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* A lower value (closer to 0) is a more feasible attack.
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*/
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int
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attackCost (const System sys)
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{
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if (switches.prune == 0)
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{
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return 0;
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}
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if (switches.prune == 1)
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{
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// Select the first attack.
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// Implied by having the cost of traces after finding an attack to be always higher.
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//
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if (sys->current_claim->failed > 0)
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{
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// we already have an attack
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return INT_MAX;
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}
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else
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{
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// return some value relating to the cost (anything less than int_max will do)
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return 1;
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}
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}
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if (switches.prune == 2)
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{
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// Use nice heuristic cf. work of Gijs Hollestelle. Hand-picked parameters.
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int cost;
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cost = 0;
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//cost += get_semitrace_length ();
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cost += 10 * selfInitiators (sys);
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cost += 7 * selfResponders (sys);
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cost += 10 * sys->num_regular_runs;
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cost += 3 * countInitiators (sys);
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cost += 2 * countBindingsDone ();
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cost += 1 * sys->num_intruder_runs;
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return cost;
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}
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error ("Unknown pruning method (cost function not found)");
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return 0;
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}
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