[pitboss] phase 07: Track J.5 + Track L.5 — XPATH_INJECTION corpus + XPath / DOM / lxml adapters

src/dynamic/framework/adapters/xpath_python.rs

@@ -0,0 +1,109 @@
+//! Python [`super::super::FrameworkAdapter`] matching XPath expression-
+//! injection sink constructions.
+//!
+//! Phase 07 (Track J.5).  Fires when the function body invokes
+//! `lxml.etree`'s XPath entry points (`Element.xpath`, `xpath`,
+//! `XPath` evaluator) and the surrounding source imports `lxml`.
+
+use crate::dynamic::framework::{FrameworkAdapter, FrameworkBinding};
+use crate::evidence::EntryKind;
+use crate::summary::FuncSummary;
+use crate::symbol::Lang;
+
+pub struct XpathPythonAdapter;
+
+const ADAPTER_NAME: &str = "xpath-python";
+
+fn callee_is_xpath_eval(name: &str) -> bool {
+    let last = name.rsplit_once('.').map(|(_, s)| s).unwrap_or(name);
+    matches!(last, "xpath" | "evaluate" | "find" | "findall" | "iterfind")
+}
+
+fn source_imports_lxml(file_bytes: &[u8]) -> bool {
+    const NEEDLES: &[&[u8]] = &[
+        b"from lxml",
+        b"import lxml",
+        b"lxml.etree",
+        b"etree.XPath",
+        b"etree.ElementTree",
+        b"xml.etree.ElementTree",
+        b"ElementTree.fromstring",
+    ];
+    NEEDLES
+        .iter()
+        .any(|n| file_bytes.windows(n.len()).any(|w| w == *n))
+}
+
+impl FrameworkAdapter for XpathPythonAdapter {
+    fn name(&self) -> &'static str {
+        ADAPTER_NAME
+    }
+
+    fn lang(&self) -> Lang {
+        Lang::Python
+    }
+
+    fn detect(
+        &self,
+        summary: &FuncSummary,
+        _ast: tree_sitter::Node<'_>,
+        file_bytes: &[u8],
+    ) -> Option<FrameworkBinding> {
+        let matches_call = super::any_callee_matches(summary, callee_is_xpath_eval);
+        let matches_source = source_imports_lxml(file_bytes);
+        if matches_call && matches_source {
+            Some(FrameworkBinding {
+                adapter: ADAPTER_NAME.to_owned(),
+                kind: EntryKind::Function,
+                route: None,
+                request_params: Vec::new(),
+                response_writer: None,
+                middleware: Vec::new(),
+            })
+        } else {
+            None
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn parse_python(src: &[u8]) -> tree_sitter::Tree {
+        let mut parser = tree_sitter::Parser::new();
+        let lang = tree_sitter::Language::from(tree_sitter_python::LANGUAGE);
+        parser.set_language(&lang).unwrap();
+        parser.parse(src, None).unwrap()
+    }
+
+    #[test]
+    fn fires_on_lxml_xpath() {
+        let src: &[u8] = b"from lxml import etree\n\
+            def run(name):\n\
+                tree = etree.fromstring(open('xpath_corpus.xml').read())\n\
+                return tree.xpath(\"//user[@name='\" + name + \"']\")\n";
+        let tree = parse_python(src);
+        let summary = FuncSummary {
+            name: "run".into(),
+            callees: vec![crate::summary::CalleeSite::bare("xpath")],
+            ..Default::default()
+        };
+        assert!(XpathPythonAdapter
+            .detect(&summary, tree.root_node(), src)
+            .is_some());
+    }
+
+    #[test]
+    fn skips_plain_function() {
+        let src: &[u8] = b"def add(a, b):\n    return a + b\n";
+        let tree = parse_python(src);
+        let summary = FuncSummary {
+            name: "add".into(),
+            ..Default::default()
+        };
+        assert!(XpathPythonAdapter
+            .detect(&summary, tree.root_node(), src)
+            .is_none());
+    }
+}