if (Options.procedureAbstraction.getValue() == 2) {
// Calls always get a fallthrough edge in optimistic mode
if (stmt.getType() == RTLGoto.Type.CALL) {
Location nextLabel = stmt.getNextLabel();
if (Program.getProgram().getHarness().contains(stmt.getAddress())) {
nextLabel = new Location(Program.getProgram().getHarness().getFallthroughAddress(stmt.getAddress()));
}
if (nextLabel != null) {
RTLUnknownProcedureCall unknownCallEdge = new RTLUnknownProcedureCall(stmt);
unknownCallEdge.setLabel(stmt.getLabel());
unknownCallEdge.setNextLabel(nextLabel);
results.add(new CFAEdge(stmt.getLabel(), nextLabel, unknownCallEdge));
sound = false;
}
}
// Replace return with halt, since control flow passes over calls anyway
else if (stmt.getType() == RTLGoto.Type.RETURN) {
sound = false;
return Collections.emptySet();
}
}
DualCompositeState dcs = (DualCompositeState)a;
// Add all edges from over-approximation
for (Tuple<RTLNumber> pair : dcs.projectionFromConcretization(stmt.getCondition(), stmt.getTargetExpression())) {
RTLNumber conditionValue = pair.get(0);
RTLNumber targetValue = pair.get(1);
Location nextLabel;
// Start building the assume expression: assume correct condition case
assert conditionValue != null;
RTLExpression assumption =
ExpressionFactory.createEqual(stmt.getCondition(), conditionValue);
if (conditionValue.equals(ExpressionFactory.FALSE)) {
// assume (condition = false), and set next statement to fallthrough
nextLabel = stmt.getNextLabel();
} else {
if (targetValue == null) {
logger.debug("No value from MAY-analysis at " + stmt.getLabel());
sound = false;
unresolvedBranches.add(stmt.getLabel());
continue;
}
// assume (condition = true AND targetExpression = targetValue)
assumption = ExpressionFactory.createAnd(
assumption,
ExpressionFactory.createEqual(
stmt.getTargetExpression(),
targetValue)
);
// set next label to jump target
nextLabel = new Location(new AbsoluteAddress(targetValue));
}
assumption = assumption.evaluate(new Context());
RTLAssume assume = new RTLAssume(assumption, stmt);
assume.setLabel(stmt.getLabel());
assume.setNextLabel(nextLabel);
// Target address sanity check
if (nextLabel.getAddress().getValue() < 10L) {
logger.warn("Control flow from " + stmt.getLabel() + " reaches address " + nextLabel.getAddress() + "!");
}
results.add(new CFAEdge(assume.getLabel(), assume.getNextLabel(), assume, Kind.MAY));
}
// Add all edges from under-approximation
for (Tuple<RTLNumber> pair : dcs.projection(stmt.getCondition(), stmt.getTargetExpression())) {
RTLNumber conditionValue = pair.get(0);
RTLNumber targetValue = pair.get(1);
Location nextLabel;
// Start building the assume expression: assume correct condition case
assert conditionValue != null;
RTLExpression assumption =
ExpressionFactory.createEqual(stmt.getCondition(), conditionValue);
if (conditionValue.equals(ExpressionFactory.FALSE)) {
// assume (condition = false), and set next statement to fallthrough
nextLabel = stmt.getNextLabel();
} else {
assert targetValue != null;
// Translate real library addresses into stub addresses. Necessary because the static analysis component
// does not know about concrete import addresses, so it uses a stub system.
if (!isProgramAddress(targetValue)) {
logger.debug(dcs.getLocation() + ": Jumping out of module to " + targetValue.toHexString());
// Attempt to map this out-of-module location to a stub
if (realToStub.containsKey(targetValue)) {
// If we saw this concrete address before, replace it by the known stub
logger.debug("Replacing concrete target " + targetValue.toHexString() + " with stub to " + program.getSymbolFor(new AbsoluteAddress(realToStub.get(targetValue))));
targetValue = realToStub.get(targetValue);
} else {
// Check the statically produced edges for one that is not yet mapped to a concrete address.
// If the over-approximation resolved an import to a stub, it's going to be contained.
boolean foundStub = false;
for (CFAEdge e : results) {
RTLNumber staticTarget = e.getTarget().getAddress().toNumericConstant();
if (!isProgramAddress(staticTarget) && !stubToReal.containsKey(staticTarget)) {
// Take the first one that's neither taken nor in the program
// TODO: This could map the wrong addresses in some (hopefully) rare cases depending on analysis order
stubToReal.put(staticTarget, targetValue);
realToStub.put(targetValue, staticTarget);
targetValue = staticTarget;
foundStub = true;
break;
}
}
if (!foundStub) {
// If we have not found anything suitable, we need to create a new stub
// FIXME: The new stub will likely have incorrect stack height adjustment.
// We should extract that information from the trace.
logger.info(dcs.getLocation() + ": Creating new stub for unknown function at " + targetValue.toHexString());
RTLNumber stubTarget = Program.getProgram().getProcAddress("JAK_UNKNOWN", "proc" + targetValue.toHexString()).toNumericConstant();
stubToReal.put(stubTarget, targetValue);
realToStub.put(targetValue, stubTarget);
targetValue = stubTarget;
}
}
}
// assume (condition = true AND targetExpression = targetValue)
assumption = ExpressionFactory.createAnd(
assumption,
ExpressionFactory.createEqual(
stmt.getTargetExpression(),
targetValue)
);
// set next label to jump target
nextLabel = new Location(new AbsoluteAddress(targetValue));
}
assumption = assumption.evaluate(new Context());
RTLAssume assume = new RTLAssume(assumption, stmt);
assume.setLabel(stmt.getLabel());
assume.setNextLabel(nextLabel);