Refuse packing through a read-only Clemory view

cle/memory.py

@@ -768,6 +768,9 @@ def load(self, addr: int, n: int) -> bytes:
     def store(self, addr, data):
         raise NotImplementedError("ClemoryReadOnlyView does not support storing")
 
+    def pack(self, addr: int, fmt: str, *data):
+        raise NotImplementedError("ClemoryReadOnlyView does not support packing")
+
     def backers(self, addr: int = 0):
         start_pos = bisect.bisect_right(self._flattened_backers, addr, key=lambda x: x[0])
         if start_pos > 0:

tests/test_clemory.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import os
 import sys
 import timeit
 import unittest
@@ -8,6 +9,8 @@
 
 import cle
 
+TEST_BASE = os.path.join(os.path.dirname(os.path.realpath(__file__)), "..", "..", "binaries", "tests")
+
 
 @unittest.skipIf(sys.platform == "emscripten", "runtime CFFI compilation is unavailable in Pyodide")
 def test_cclemory():  # pylint: disable=no-member
@@ -118,6 +121,30 @@ def test_clemory_contains():
     assert clemory.consecutive is True
 
 
+def test_clemory_read_only_view_refuses_writes():
+    loader = cle.Loader(os.path.join(TEST_BASE, "x86_64", "fauxware"), auto_load_libs=False)
+    loader.gen_ro_memview()
+    view = loader.memory_ro_view
+    assert view is not None
+
+    entry = loader.main_object.entry
+    before = loader.memory.load(entry, 16)
+    nops = b"\x90" * 8
+
+    for write in (
+        lambda: view.store(entry, nops),
+        lambda: view.pack(entry, "8s", nops),
+        lambda: view.pack_word(entry, int.from_bytes(nops, "little")),
+    ):
+        refused = False
+        try:
+            write()
+        except NotImplementedError:
+            refused = True
+        assert refused
+        assert loader.memory.load(entry, 16) == before
+
+
 def main():
     g = globals()
     for func_name, func in g.items():