Merge pull request #1542 from gcmoreira/linux_parity_release_harden_process_listing

linux: Ensure task listing functions yield only valid tasks

Author: ikelos

volatility3/framework/plugins/linux/pslist.py

@@ -34,7 +34,7 @@ class PsList(interfaces.plugins.PluginInterface, timeliner.TimeLinerInterface):
     """Lists the processes present in a particular linux memory image."""
 
     _required_framework_version = (2, 13, 0)
-    _version = (4, 0, 0)
+    _version = (4, 1, 0)
 
     @classmethod
     def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
@@ -250,6 +250,9 @@ def list_tasks(
 
         # Note that the init_task itself is not yielded, since "ps" also never shows it.
         for task in init_task.tasks:
+            if not task.is_valid():
+                continue
+
             if filter_func(task):
                 continue
 

volatility3/framework/symbols/linux/extensions/__init__.py

@@ -307,6 +307,46 @@ def section_strtab(self):
 
 
 class task_struct(generic.GenericIntelProcess):
+    def is_valid(self) -> bool:
+        layer = self._context.layers[self.vol.layer_name]
+        # Make sure the entire task content is readable
+        if not layer.is_valid(self.vol.offset, self.vol.size):
+            return False
+
+        if self.pid < 0 or self.tgid < 0:
+            return False
+
+        if self.has_member("signal") and not (
+            self.signal and self.signal.is_readable()
+        ):
+            return False
+
+        if self.has_member("nsproxy") and not (
+            self.nsproxy and self.nsproxy.is_readable()
+        ):
+            return False
+
+        if self.has_member("real_parent") and not (
+            self.real_parent and self.real_parent.is_readable()
+        ):
+            return False
+
+        if (
+            self.has_member("active_mm")
+            and self.active_mm
+            and not self.active_mm.is_readable()
+        ):
+            return False
+
+        if self.mm:
+            if not self.mm.is_readable():
+                return False
+
+            if self.mm != self.active_mm:
+                return False
+
+        return True
+
     def add_process_layer(
         self, config_prefix: Optional[str] = None, preferred_name: Optional[str] = None
     ) -> Optional[str]:
@@ -401,6 +441,8 @@ def get_threads(self) -> Iterable[interfaces.objects.ObjectInterface]:
         tasks_iterable = self._get_tasks_iterable()
         threads_seen = set([self.vol.offset])
         for task in tasks_iterable:
+            if not task.is_valid():
+                continue
             if task.vol.offset not in threads_seen:
                 threads_seen.add(task.vol.offset)
                 yield task