Fixing operator code bug in control-flow sensitive DFG

Fraunhofer-AISEC · Mar 14, 2024 · 8a49957 · 8a49957
1 parent 305809e
commit 8a49957
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Showing 3 changed files with 12 additions and 13 deletions.
diff --git a/cpg-analysis/src/main/kotlin/de/fraunhofer/aisec/cpg/analysis/ValueEvaluator.kt b/cpg-analysis/src/main/kotlin/de/fraunhofer/aisec/cpg/analysis/ValueEvaluator.kt
@@ -29,7 +29,6 @@ import de.fraunhofer.aisec.cpg.graph.AccessValues
 import de.fraunhofer.aisec.cpg.graph.HasOperatorCode
 import de.fraunhofer.aisec.cpg.graph.Node
 import de.fraunhofer.aisec.cpg.graph.declarations.VariableDeclaration
-import de.fraunhofer.aisec.cpg.graph.firstAssignment
 import de.fraunhofer.aisec.cpg.graph.statements.expressions.*
 import de.fraunhofer.aisec.cpg.graph.statements.expressions.AssignExpression
 import org.slf4j.Logger
@@ -110,14 +109,9 @@ open class ValueEvaluator(
     }
 
     protected fun handleVariableDeclaration(node: VariableDeclaration, depth: Int): Any? {
-        // If we have an initializer, we can use it
-        if (node.initializer != null) {
-            return evaluateInternal(node.initializer, depth + 1)
-        }
-
-        // Otherwise, we can try the firstAssignment. However, we actually should just use the DFG,
-        // but that does not seem to work?
-        return evaluateInternal(node.firstAssignment, depth + 1)
+        // If we have an initializer, we can use it. However, we actually should just use the DFG
+        // instead and do something similar to handleReference
+        return evaluateInternal(node.initializer, depth + 1)
     }
 
     /** Under certain circumstances, an assignment can also be used as an expression. */

diff --git a/cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/passes/ControlFlowSensitiveDFGPass.kt b/cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/passes/ControlFlowSensitiveDFGPass.kt
@@ -411,7 +411,8 @@ open class ControlFlowSensitiveDFGPass(ctx: TranslationContext) : EOGStarterPass
 
     protected fun isSimpleAssignment(currentNode: Node): Boolean {
         contract { returns(true) implies (currentNode is AssignExpression) }
-        return currentNode is AssignExpression && currentNode.operatorCode == "="
+        return currentNode is AssignExpression &&
+            (currentNode.operatorCode == "=" || currentNode.operatorCode == ":=")
     }
 
     /** Checks if the node is an increment or decrement operator (e.g. i++, i--, ++i, --i) */

diff --git a/cpg-language-go/src/test/kotlin/de/fraunhofer/aisec/cpg/frontends/golang/ExpressionTest.kt b/cpg-language-go/src/test/kotlin/de/fraunhofer/aisec/cpg/frontends/golang/ExpressionTest.kt
@@ -176,7 +176,7 @@ class ExpressionTest {
     }
 
     @Test
-    fun testShortAssgin() {
+    fun testShortAssign() {
         val topLevel = Path.of("src", "test", "resources", "golang")
         val tu =
             TestUtils.analyzeAndGetFirstTU(
@@ -192,8 +192,12 @@ class ExpressionTest {
         assertNotNull(lit5)
         println(lit5.printDFG())
 
-        val x = tu.refs("x").firstOrNull()
+        val x = tu.refs("x").lastOrNull()
         assertNotNull(x)
-        println(x.printDFG())
+
+        val paths = x.followPrevDFGEdgesUntilHit { it == lit5 }
+        assertEquals(3, paths.fulfilled.firstOrNull()?.size)
+
+        assertEquals(5, x.evaluate())
     }
 }