[pitboss] phase 05: Track J.3 + Track L.3 — XXE corpus + DocumentBuilder / lxml / libxml / SimpleXML adapters

src/dynamic/framework/adapters/xxe_php.rs

@@ -0,0 +1,120 @@
+//! PHP [`super::super::FrameworkAdapter`] matching XXE-prone XML
+//! parser constructions.
+//!
+//! Phase 05 (Track J.3).  Fires when the function body invokes one of
+//! the canonical PHP XML entry points (`simplexml_load_string`,
+//! `simplexml_load_file`, `DOMDocument::loadXML`,
+//! `DOMDocument::load`, `xml_parser_create`) and the surrounding
+//! source mentions an XML / libxml symbol — the parser, by default
+//! and under `libxml_disable_entity_loader(false)`, expands external
+//! entities.
+
+use crate::dynamic::framework::{FrameworkAdapter, FrameworkBinding};
+use crate::evidence::EntryKind;
+use crate::summary::FuncSummary;
+use crate::symbol::Lang;
+
+pub struct XxePhpAdapter;
+
+const ADAPTER_NAME: &str = "xxe-php";
+
+fn callee_is_xml_parser(name: &str) -> bool {
+    let last = name.rsplit_once("::").map(|(_, s)| s)
+        .or_else(|| name.rsplit_once('.').map(|(_, s)| s))
+        .or_else(|| name.rsplit_once("->").map(|(_, s)| s))
+        .unwrap_or(name);
+    matches!(
+        last,
+        "simplexml_load_string"
+            | "simplexml_load_file"
+            | "loadXML"
+            | "load"
+            | "xml_parser_create"
+            | "xml_parse"
+    )
+}
+
+fn source_imports_xml(file_bytes: &[u8]) -> bool {
+    const NEEDLES: &[&[u8]] = &[
+        b"simplexml_load_string",
+        b"simplexml_load_file",
+        b"DOMDocument",
+        b"xml_parser_create",
+        b"libxml_disable_entity_loader",
+        b"LIBXML_NOENT",
+    ];
+    NEEDLES
+        .iter()
+        .any(|n| file_bytes.windows(n.len()).any(|w| w == *n))
+}
+
+impl FrameworkAdapter for XxePhpAdapter {
+    fn name(&self) -> &'static str {
+        ADAPTER_NAME
+    }
+
+    fn lang(&self) -> Lang {
+        Lang::Php
+    }
+
+    fn detect(
+        &self,
+        summary: &FuncSummary,
+        _ast: tree_sitter::Node<'_>,
+        file_bytes: &[u8],
+    ) -> Option<FrameworkBinding> {
+        let matches_call = super::any_callee_matches(summary, callee_is_xml_parser);
+        let matches_source = source_imports_xml(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_php(src: &[u8]) -> tree_sitter::Tree {
+        let mut parser = tree_sitter::Parser::new();
+        let lang = tree_sitter::Language::from(tree_sitter_php::LANGUAGE_PHP);
+        parser.set_language(&lang).unwrap();
+        parser.parse(src, None).unwrap()
+    }
+
+    #[test]
+    fn fires_on_simplexml_load_string() {
+        let src: &[u8] = b"<?php\nfunction run($body) {\n    return simplexml_load_string($body);\n}\n";
+        let tree = parse_php(src);
+        let summary = FuncSummary {
+            name: "run".into(),
+            callees: vec![crate::summary::CalleeSite::bare("simplexml_load_string")],
+            ..Default::default()
+        };
+        assert!(XxePhpAdapter
+            .detect(&summary, tree.root_node(), src)
+            .is_some());
+    }
+
+    #[test]
+    fn skips_plain_function() {
+        let src: &[u8] = b"<?php\nfunction add($a, $b) { return $a + $b; }\n";
+        let tree = parse_php(src);
+        let summary = FuncSummary {
+            name: "add".into(),
+            ..Default::default()
+        };
+        assert!(XxePhpAdapter
+            .detect(&summary, tree.root_node(), src)
+            .is_none());
+    }
+}