/*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html.
*
* This file is a derivative of code released under the terms listed below.
*
*/
/*
*
* Copyright (c) 2009-2012,
*
* Galois, Inc. (Aaron Tomb <atomb@galois.com>, Rogan Creswick <creswick@galois.com>)
* Steve Suh <suhsteve@gmail.com>
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The names of the contributors may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*
*/
package org.scandroid.flow.functions;
import java.util.List;
import org.scandroid.domain.CodeElement;
import org.scandroid.domain.DomainElement;
import org.scandroid.domain.IFDSTaintDomain;
import com.ibm.wala.dataflow.IFDS.IUnaryFlowFunction;
import com.ibm.wala.ssa.ISSABasicBlock;
import com.ibm.wala.util.intset.IntSet;
import com.ibm.wala.util.intset.MutableSparseIntSet;
final class PairBasedFlowFunction <E extends ISSABasicBlock> implements IUnaryFlowFunction {
// private static final Logger logger =
// LoggerFactory.getLogger(PairBasedFlowFunction.class);
private final List<UseDefPair> useToDefList;
private final IFDSTaintDomain<E> domain;
public PairBasedFlowFunction(IFDSTaintDomain<E> domain, List<UseDefPair> useToDefList) {
this.domain = domain;
this.useToDefList = useToDefList;
}
@Override
public IntSet getTargets(int d) {
//logger.debug("getTargets("+d+")");
if (0 == d) {
//logger.debug("getTargets("+d+"): {0}");
return TaintTransferFunctions.ZERO_SET;
}
MutableSparseIntSet set = MutableSparseIntSet.makeEmpty();
DomainElement de = domain.getMappedObject(d);
// Here we list what facts we pass through. If a fact was true
// before executing this instruction, it'll be true after,
// unless we created a new definition of its associated
// CodeElement.
// see if D is still true; if so, pass it through:
// (this corresponds to the vertical 'pass through' arrows in the RHS paper)
// we actually assume that D passes through, unless there
// is evidence to the contrary. Because of this, instructions will
// 'default' to propagating taints that were not relevant to that
// instruction, which is what we want.
set.add(d);
for (UseDefPair udPair : useToDefList) {
CodeElement def = udPair.getDef();
if (def.equals(de.codeElement)) {
// this instruction redefined D, so we
// do *not* pass it through - this conditional has
// contradicted our assumption that D should be passed through,
// so remove it from the set:
set.remove(d);
break;
}
}
////////////////////////////////////////////////////////////////
// see if the taints associated with D also flow through to any
// other domain elements:
for (UseDefPair udPair : useToDefList) {
CodeElement use = udPair.getUse();
if (use.equals(de.codeElement)) {
// ok, the d element flows to the def, so we add that def
// and keep looking.
DomainElement newDE =
new DomainElement(udPair.getDef(), de.taintSource);
set.add(domain.getMappedIndex(newDE));
}
}
// logger.debug("getTargets("+d+"): "+set);
return set;
}
}