Rust: Exclude sources in macro expansions.

Author: geoffw0

rust/ql/src/queries/security/CWE-825/AccessAfterLifetime.ql

@@ -40,7 +40,8 @@ where
   AccessAfterLifetimeFlow::flowPath(sourceNode, sinkNode) and
   // check that the dereference is outside the lifetime of the target
   AccessAfterLifetime::dereferenceAfterLifetime(sourceNode.getNode(), sinkNode.getNode(), target) and
-  // exclude sinks in macros, since these results are difficult to interpret
+  // exclude cases with sources / sinks in macros, since these results are difficult to interpret
+  not sourceNode.getNode().asExpr().getExpr().isFromMacroExpansion() and
   not sinkNode.getNode().asExpr().getExpr().isFromMacroExpansion()
 select sinkNode.getNode(), sourceNode, sinkNode,
   "Access of a pointer to $@ after its lifetime has ended.", target, target.toString()

rust/ql/test/query-tests/security/CWE-825/AccessAfterLifetime.expected

@@ -22,7 +22,6 @@
 | lifetime.rs:667:14:667:17 | ref1 | lifetime.rs:654:31:654:35 | &str1 | lifetime.rs:667:14:667:17 | ref1 | Access of a pointer to $@ after its lifetime has ended. | lifetime.rs:653:8:653:11 | str1 | str1 |
 | lifetime.rs:667:14:667:17 | ref1 | lifetime.rs:655:11:655:25 | &raw const str2 | lifetime.rs:667:14:667:17 | ref1 | Access of a pointer to $@ after its lifetime has ended. | lifetime.rs:651:7:651:10 | str2 | str2 |
 | lifetime.rs:734:12:734:13 | r1 | lifetime.rs:719:26:719:34 | &... | lifetime.rs:734:12:734:13 | r1 | Access of a pointer to $@ after its lifetime has ended. | lifetime.rs:719:19:719:20 | v2 | v2 |
-| lifetime.rs:771:12:771:14 | ptr | lifetime.rs:769:12:769:23 | &val | lifetime.rs:771:12:771:14 | ptr | Access of a pointer to $@ after its lifetime has ended. | lifetime.rs:769:12:769:23 | val | val |
 | lifetime.rs:791:10:791:12 | ptr | lifetime.rs:781:9:781:12 | &val | lifetime.rs:791:10:791:12 | ptr | Access of a pointer to $@ after its lifetime has ended. | lifetime.rs:779:6:779:8 | val | val |
 edges
 | deallocation.rs:148:6:148:7 | p1 | deallocation.rs:151:14:151:15 | p1 | provenance |  |

rust/ql/test/query-tests/security/CWE-825/lifetime.rs

@@ -766,9 +766,9 @@ pub fn test_macros() {
 	my_macro1!();
 	my_macro1!();
 
-	let ptr = my_macro2!(); // $ SPURIOUS: Source[rust/access-after-lifetime-ended]=ptr
+	let ptr = my_macro2!();
 	unsafe {
-		let v = *ptr; // $ SPURIOUS: Alert[rust/access-after-lifetime-ended]=ptr
+		let v = *ptr;
 		println!("	v = {v}");
 	}
 }