Fail closed on unexpected health.h layouts

Author: adeebshihadeh

python/__init__.py

@@ -45,9 +45,11 @@ def calculate_checksum(data):
 
 def _parse_c_struct(path, name):
   with open(path) as f:
-    body = f.read().split(f"struct __attribute__((packed)) {name} {{", 1)[1].split("};", 1)[0]
-  fmt = "".join({"uint8_t": "B", "uint16_t": "H", "uint32_t": "I", "float": "f"}[t] for t in re.findall(r"^\s*(uint(?:8|16|32)_t|float)\s+\w+;", body, re.M))
-  return struct.Struct("<" + fmt)
+    lines = [l.strip() for l in f.read().split(f"struct __attribute__((packed)) {name} {{", 1)[1].split("};", 1)[0].splitlines() if l.strip()]
+  fields = [re.fullmatch(r"(uint(?:8|16|32)_t|float)\s+\w+;", l) for l in lines]
+  if not all(fields):
+    raise ValueError(f"unsupported {name} layout in {path}")
+  return struct.Struct("<" + "".join({"uint8_t": "B", "uint16_t": "H", "uint32_t": "I", "float": "f"}[m[1]] for m in fields))
 
 def pack_can_buffer(arr, chunk=False, fd=False):
   snds = [bytearray(), ]

tests/test_health_parser.py

@@ -0,0 +1,13 @@
+import tempfile
+
+import pytest
+
+from panda.python import _parse_c_struct
+
+
+def test_parse_c_struct_rejects_unknown_field_types():
+  with tempfile.NamedTemporaryFile(mode="w", suffix=".h") as f:
+    f.write("struct __attribute__((packed)) health_t {\n  uint32_t ok;\n  bool nope;\n};\n")
+    f.flush()
+    with pytest.raises(ValueError, match="unsupported health_t layout"):
+      _parse_c_struct(f.name, "health_t")