Merge pull request #3010 from onflow/bastian/defensive-dereference-check

onflow · Jan 11, 2024 · 08be353 · 08be353
2 parents 656acc3 + 26d4494
commit 08be353
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Showing 3 changed files with 89 additions and 3 deletions.
diff --git a/runtime/interpreter/errors.go b/runtime/interpreter/errors.go
@@ -1051,3 +1051,16 @@ func (e InclusiveRangeConstructionError) Error() string {
 	}
 	return fmt.Sprintf("%s: %s", message, e.Message)
 }
+
+// ResourceReferenceDereferenceError
+type ResourceReferenceDereferenceError struct {
+	LocationRange
+}
+
+var _ errors.InternalError = ResourceReferenceDereferenceError{}
+
+func (ResourceReferenceDereferenceError) IsInternalError() {}
+
+func (e ResourceReferenceDereferenceError) Error() string {
+	return "internal error: resource-references cannot be dereferenced"
+}
diff --git a/runtime/interpreter/value.go b/runtime/interpreter/value.go
@@ -19932,8 +19932,16 @@ func DereferenceValue(
 	locationRange LocationRange,
 	referenceValue ReferenceValue,
 ) Value {
-	referencedValue := referenceValue.ReferencedValue(inter, locationRange, true)
-	return (*referencedValue).Transfer(
+	referencedValue := *referenceValue.ReferencedValue(inter, locationRange, true)
+
+	// Defensive check: ensure that the referenced value is not a resource
+	if referencedValue.IsResourceKinded(inter) {
+		panic(ResourceReferenceDereferenceError{
+			LocationRange: locationRange,
+		})
+	}
+
+	return referencedValue.Transfer(
 		inter,
 		locationRange,
 		atree.Address{},

diff --git a/runtime/tests/interpreter/reference_test.go b/runtime/tests/interpreter/reference_test.go
@@ -1648,7 +1648,7 @@ func TestInterpretReferenceTrackingOnInvocation(t *testing.T) {
     `)
 
 	_, err := inter.Invoke("main")
-	require.Error(t, err)
+	RequireError(t, err)
 
 	require.ErrorAs(t, err, &interpreter.InvalidatedResourceReferenceError{})
 }
@@ -2956,4 +2956,69 @@ func TestInterpretDereference(t *testing.T) {
 		)
 	})
 
+	t.Run("Resource", func(t *testing.T) {
+		t.Parallel()
+
+		t.Run("direct", func(t *testing.T) {
+			t.Parallel()
+
+			inter, err := parseCheckAndInterpretWithOptions(t,
+				`
+                  resource R {}
+
+                  fun main() {
+                      let r1 <- create R()
+                      let r1Ref: &R = &r1
+                      let r2 <- *r1Ref
+                      destroy r1
+                      destroy r2
+                  }
+                `,
+				ParseCheckAndInterpretOptions{
+					HandleCheckerError: func(err error) {
+						errs := checker.RequireCheckerErrors(t, err, 1)
+
+						require.IsType(t, &sema.InvalidUnaryOperandError{}, errs[0])
+					},
+				},
+			)
+			require.NoError(t, err)
+
+			_, err = inter.Invoke("main")
+			RequireError(t, err)
+
+			require.ErrorAs(t, err, &interpreter.ResourceReferenceDereferenceError{})
+		})
+
+		t.Run("array", func(t *testing.T) {
+			t.Parallel()
+
+			inter, err := parseCheckAndInterpretWithOptions(t,
+				`
+                  resource R {}
+
+                  fun main() {
+                      let rs1 <- [<- create R()]
+                      let rs1Ref: &[R] = &rs1
+                      let rs2 <- *rs1Ref
+                      destroy rs1
+                      destroy rs2
+                  }
+                `,
+				ParseCheckAndInterpretOptions{
+					HandleCheckerError: func(err error) {
+						errs := checker.RequireCheckerErrors(t, err, 1)
+
+						require.IsType(t, &sema.InvalidUnaryOperandError{}, errs[0])
+					},
+				},
+			)
+			require.NoError(t, err)
+
+			_, err = inter.Invoke("main")
+			RequireError(t, err)
+
+			require.ErrorAs(t, err, &interpreter.ResourceReferenceDereferenceError{})
+		})
+	})
 }