🛡️ Sentinel: [CRITICAL] Fix path traversal in module resolution

.jules/sentinel.md

@@ -0,0 +1,5 @@
+
+## 2024-05-22 - [Fix path traversal vulnerability in module resolution]
+**Vulnerability:** The manual path resolution fallback in the TypeScript extractor popped path components unconditionally when encountering `..` (ParentDir), ignoring edge cases where `..` escapes the root directory or when leading `..` components should be preserved.
+**Learning:** Manual path normalization logic must strictly follow semantic path construction and guard against unexpected component states like traversing above `RootDir` or losing relative paths like `../../foo`.
+**Prevention:** Always validate the existing state of path components before modifying them during `ParentDir` handling, treating `RootDir` and `Prefix` as non-poppable, and preserving `ParentDir` when needed.

crates/flow/src/incremental/extractors/typescript.rs

@@ -807,9 +807,14 @@ impl TypeScriptDependencyExtractor {
                 let mut components = Vec::new();
                 for component in resolved.components() {
                     match component {
-                        std::path::Component::ParentDir => {
-                            components.pop();
-                        }
+                        std::path::Component::ParentDir => match components.last() {
+                            Some(std::path::Component::RootDir)
+                            | Some(std::path::Component::Prefix(_)) => {}
+                            Some(std::path::Component::Normal(_)) => {
+                                components.pop();
+                            }
+                            _ => components.push(component),
+                        },
                         std::path::Component::CurDir => {}
                         _ => components.push(component),
                     }

crates/rule-engine/src/check_var.rs

@@ -104,9 +104,9 @@ fn get_vars_from_rules<'r>(rule: &'r Rule, utils: &'r RuleRegistration) -> Rapid
     vars
 }
 
-fn check_var_in_constraints<'r>(
+fn check_var_in_constraints(
     mut vars: RapidSet<String>,
-    constraints: &'r RapidMap<thread_ast_engine::meta_var::MetaVariableID, Rule>,
+    constraints: &RapidMap<thread_ast_engine::meta_var::MetaVariableID, Rule>,
 ) -> RResult<RapidSet<String>> {
     for rule in constraints.values() {
         for var in rule.defined_vars() {
@@ -125,9 +125,9 @@ fn check_var_in_constraints<'r>(
     Ok(vars)
 }
 
-fn check_var_in_transform<'r>(
+fn check_var_in_transform(
     mut vars: RapidSet<String>,
-    transform: &'r Option<Transform>,
+    transform: &Option<Transform>,
 ) -> RResult<RapidSet<String>> {
     let Some(transform) = transform else {
         return Ok(vars);