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More robust implementation
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@oxisto
oxisto committed Jan 28, 2025
1 parent 2b2b7b4 commit d07e609
Showing 1 changed file with 53 additions and 28 deletions.
81 changes: 53 additions & 28 deletions cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/graph/Extensions.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@ import de.fraunhofer.aisec.cpg.graph.statements.*
import de.fraunhofer.aisec.cpg.graph.statements.expressions.*
import de.fraunhofer.aisec.cpg.graph.statements.expressions.Block
import de.fraunhofer.aisec.cpg.helpers.SubgraphWalker
import kotlin.collections.firstOrNull
import kotlin.math.absoluteValue

/**
Expand Down Expand Up @@ -227,7 +228,7 @@ fun Node.followPrevFullDFGEdgesUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, _ -> currentNode.prevFullDFG },
x = { currentNode, _, _ -> currentNode.prevFullDFG },
collectFailedPaths = collectFailedPaths,
findAllPossiblePaths = findAllPossiblePaths,
predicate = predicate,
Expand Down Expand Up @@ -267,7 +268,7 @@ fun Node.followPrevDFGEdgesUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, ctx ->
x = { currentNode, ctx, path ->
if (
useIndexStack &&
currentNode is InitializerListExpression &&
Expand Down Expand Up @@ -324,10 +325,10 @@ fun Node.followPrevDFGEdgesUntilHit(
*/
class Context(
val indexStack: SimpleStack<IndexedDataflowGranularity> = SimpleStack(),
val callStack: SimpleStack<CallExpression> = SimpleStack(),
val callStack: ArrayDeque<CallExpression> = ArrayDeque<CallExpression>(),
) {
fun clone(): Context {
return Context(indexStack.clone(), callStack.clone())
return Context(indexStack.clone(), ArrayDeque(callStack))
}
}

Expand All @@ -340,6 +341,9 @@ class SimpleStack<T>() {
deque.addFirst(newElem)
}

val current: T?
get() = deque.firstOrNull()

fun checkAndPop(elemToPop: T): Boolean {
if (deque.firstOrNull() == elemToPop) {
deque.removeFirst()
Expand Down Expand Up @@ -475,7 +479,7 @@ fun Node.followNextPDGUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, _ ->
x = { currentNode, _, _ ->
val nextNodes = currentNode.nextPDG.toMutableList()
if (interproceduralAnalysis) {
nextNodes.addAll((currentNode as? CallExpression)?.calls ?: listOf())
Expand Down Expand Up @@ -504,7 +508,7 @@ fun Node.followNextCDGUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, _ ->
x = { currentNode, _, _ ->
val nextNodes = currentNode.nextCDG.toMutableList()
if (interproceduralAnalysis) {
nextNodes.addAll((currentNode as? CallExpression)?.calls ?: listOf())
Expand Down Expand Up @@ -534,7 +538,7 @@ fun Node.followPrevPDGUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, _ ->
x = { currentNode, _, _ ->
val nextNodes = currentNode.prevPDG.toMutableList()
if (interproceduralAnalysis) {
nextNodes.addAll(
Expand Down Expand Up @@ -568,7 +572,7 @@ fun Node.followPrevCDGUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, _ ->
x = { currentNode, _, _ ->
val nextNodes = currentNode.prevCDG.toMutableList()
if (interproceduralAnalysis) {
nextNodes.addAll(
Expand Down Expand Up @@ -596,7 +600,7 @@ fun Node.followPrevCDGUntilHit(
* not mandatory**. If the list "failed" is empty, the path is mandatory.
*/
inline fun Node.followXUntilHit(
noinline x: (Node, Context) -> Collection<Node>,
noinline x: (Node, Context, List<Node>) -> Collection<Node>,
collectFailedPaths: Boolean = true,
findAllPossiblePaths: Boolean = true,
context: Context = Context(),
Expand All @@ -621,7 +625,7 @@ inline fun Node.followXUntilHit(
alreadySeenNodes.add(currentNode)
// The last node of the path is where we continue. We get all of its outgoing CDG edges and
// follow them
var nextNodes = x(currentNode, currentContext)
var nextNodes = x(currentNode, currentContext, currentPath.first)

// No further nodes in the path and the path criteria are not satisfied.
if (nextNodes.isEmpty() && collectFailedPaths) failedPaths.add(currentPath.first)
Expand Down Expand Up @@ -672,7 +676,7 @@ fun Node.followNextFullDFGEdgesUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, _ -> currentNode.nextFullDFG },
x = { currentNode, _, _ -> currentNode.nextFullDFG },
collectFailedPaths = collectFailedPaths,
findAllPossiblePaths = findAllPossiblePaths,
predicate = predicate,
Expand All @@ -695,7 +699,7 @@ fun Node.followNextDFGEdgesUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, ctx ->
x = { currentNode, ctx, path ->
if (
useIndexStack &&
currentNode is InitializerListExpression &&
Expand Down Expand Up @@ -726,7 +730,7 @@ fun Node.followNextDFGEdgesUntilHit(
currentNode.nextDFGEdges.forEach {
if (it is ContextSensitiveDataflow && it.callingContext is CallingContextIn) {
// Push the call of our calling context to the stack
ctx.callStack.push(it.callingContext.call)
ctx.callStack.addFirst(it.callingContext.call)
}
if (
it.end is InitializerListExpression &&
Expand All @@ -739,21 +743,33 @@ fun Node.followNextDFGEdgesUntilHit(
}

// We need to filter out the edges which based on the stack
currentNode.nextDFGEdges
.filter {
if (ctx.callStack.isEmpty()) {
true
} else if (
it is ContextSensitiveDataflow && it.callingContext is CallingContextOut
) {
// We are only interested in outgoing edges from our current "call-in".
// If we found it, we can pop it.
ctx.callStack.checkAndPop(it.callingContext.call)
} else {
true
val selected =
currentNode.nextDFGEdges
.filter {
if (ctx.callStack.isEmpty()) {
true
} else if (
it is ContextSensitiveDataflow &&
it.callingContext is CallingContextOut
) {
// We are only interested in outgoing edges from our current
// "call-in", i.e., the call expression that is on the stack.
ctx.callStack.firstOrNull() == it.callingContext.call
} else {
true
}
}
.map { it.end }

// Let's do any remaining pop'ing
currentNode.nextDFGEdges.forEach {
if (it is ContextSensitiveDataflow && it.callingContext is CallingContextOut) {
// Pop the current call, if it's on top
ctx.callStack.removeIfFirst<CallExpression>(it.callingContext.call)
}
.map { it.end }
}

selected
}
},
collectFailedPaths = collectFailedPaths,
Expand All @@ -778,7 +794,7 @@ fun Node.followNextEOGEdgesUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, _ ->
x = { currentNode, _, _ ->
currentNode.nextEOGEdges.filter { it.unreachable != true }.map { it.end }
},
collectFailedPaths = collectFailedPaths,
Expand All @@ -803,7 +819,7 @@ fun Node.followPrevEOGEdgesUntilHit(
predicate: (Node) -> Boolean,
): FulfilledAndFailedPaths {
return followXUntilHit(
x = { currentNode, _ ->
x = { currentNode, _, _ ->
currentNode.prevEOGEdges.filter { it.unreachable != true }.map { it.start }
},
collectFailedPaths = collectFailedPaths,
Expand Down Expand Up @@ -1291,3 +1307,12 @@ val Expression.isImported: Boolean
get() {
return this.importedFrom.isNotEmpty()
}

private fun <T> ArrayDeque<T>.removeIfFirst(element: T): Boolean {
return if (firstOrNull() == element) {
removeFirst()
true
} else {
false
}
}

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