Merge pull request #1671 from volatilityfoundation/fix_tracing_plugins

Fix several bugs found in the tracing plugins during mass testing

volatility3/framework/plugins/linux/tracing/ftrace.py

@@ -5,7 +5,7 @@
 # Public researches: https://i.blackhat.com/USA21/Wednesday-Handouts/us-21-Fixing-A-Memory-Forensics-Blind-Spot-Linux-Kernel-Tracing-wp.pdf
 
 import logging
-from typing import Dict, List, Iterable, Optional
+from typing import Dict, List, Generator
 from enum import Enum
 from dataclasses import dataclass
 
@@ -67,7 +67,7 @@ class CheckFtrace(interfaces.plugins.PluginInterface):
     Investigate the ftrace infrastructure to uncover kernel attached callbacks, which can be leveraged
     to hook kernel functions and modify their behaviour."""
 
-    _version = (1, 0, 0)
+    _version = (2, 0, 0)
     _required_framework_version = (2, 19, 0)
 
     @classmethod
@@ -103,32 +103,35 @@ class CheckFtrace(interfaces.plugins.PluginInterface):
     def extract_hash_table_filters(
         cls,
         ftrace_ops: interfaces.objects.ObjectInterface,
-    ) -> Optional[Iterable[interfaces.objects.ObjectInterface]]:
+    ) -> Generator[interfaces.objects.ObjectInterface, None, None]:
         """Wrap the process of walking to every ftrace_func_entry of an ftrace_ops.
         Those are stored in a hash table of filters that indicates the addresses hooked.
 
         Args:
             ftrace_ops: The ftrace_ops struct to walk through
 
-        Returns:
+        Return, None, None:
             An iterable of ftrace_func_entry structs
         """
 
+        if hasattr(ftrace_ops, "func_hash"):
+            ftrace_hash = ftrace_ops.func_hash.filter_hash
+        else:
+            ftrace_hash = ftrace_ops.filter_hash
+
         try:
-            current_bucket_ptr = ftrace_ops.func_hash.filter_hash.buckets.first
+            current_bucket_ptr = ftrace_hash.buckets.first
         except exceptions.InvalidAddressException:
             vollog.log(
                 constants.LOGLEVEL_VV,
                 f"ftrace_func_entry list of ftrace_ops@{ftrace_ops.vol.offset:#x} is empty/invalid. Skipping it...",
             )
-            return []
+            return
 
         while current_bucket_ptr.is_readable():
             yield current_bucket_ptr.dereference().cast("ftrace_func_entry")
             current_bucket_ptr = current_bucket_ptr.next
 
-        return None
-
     @classmethod
     def parse_ftrace_ops(
         cls,
@@ -137,7 +140,7 @@ class CheckFtrace(interfaces.plugins.PluginInterface):
         known_modules: Dict[str, List[extensions.module]],
         ftrace_ops: interfaces.objects.ObjectInterface,
         run_hidden_modules: bool = True,
-    ) -> Optional[Iterable[ParsedFtraceOps]]:
+    ) -> Generator[ParsedFtraceOps, None, None]:
         """Parse an ftrace_ops struct to highlight ftrace kernel hooking.
         Iterates over embedded ftrace_func_entry entries, which point to hooked memory areas.
 
@@ -234,12 +237,10 @@ if the "hidden_modules" key is present in known_modules.
                 formatted_ftrace_flags,
             )
 
-        return None
-
     @classmethod
     def iterate_ftrace_ops_list(
         cls, context: interfaces.context.ContextInterface, kernel_name: str
-    ) -> Optional[Iterable[interfaces.objects.ObjectInterface]]:
+    ) -> Generator[interfaces.objects.ObjectInterface, None, None]:
         """Iterate over (ftrace_ops *)ftrace_ops_list.
 
         Returns:

volatility3/framework/plugins/linux/tracing/tracepoints.py

@@ -116,18 +116,25 @@ class CheckTracepoints(interfaces.plugins.PluginInterface):
             known_modules: A dict of known modules, used to locate callbacks origin. Typically obtained through modxview.run_modules_scanners().
             tracepoint: The tracepoint struct to parse
             run_hidden_modules: Whether to run the hidden_modules plugin or not. Note: it won't be run, even if specified, \
-if the "hidden_modules" key is present in known_modules.
+            if the "hidden_modules" key is present in known_modules.
 
         Yields:
             An iterable of ParsedTracepointFunc dataclasses, containing a selection of useful fields related to a tracepoint struct
         """
-
         kernel = context.modules[kernel_name]
         kernel_layer = context.layers[kernel.layer_name]
 
         for tracepoint_func in cls.iterate_tracepoint_funcs(
             context, kernel_layer.name, tracepoint
         ):
+            try:
+                tracepoint_name = utility.pointer_to_string(tracepoint.name, count=512)
+            except exceptions.InvalidAddressException:
+                vollog.debug(
+                    f"Tracepoint function at {tracepoint.vol.offset:#x} is smeared."
+                )
+                continue
+
             probe_handler_address = tracepoint_func.func
             probe_handler_symbol = module_address = module_name = None
 
@@ -183,16 +190,21 @@ if the "hidden_modules" key is present in known_modules.
                     probe_handler_address
                 )
             else:
-                vollog.warning(
+                vollog.debug(
                     f"Could not determine tracepoint@{tracepoint.vol.offset:#x} probe handler {probe_handler_address:#x} module origin.",
                 )
 
+            if hasattr(tracepoint_func, "prio"):
+                prio = tracepoint_func.prio
+            else:
+                prio = None
+
             yield ParsedTracepointFunc(
-                utility.pointer_to_string(tracepoint.name, count=512),
+                tracepoint_name,
                 tracepoint.vol.offset,
                 probe_handler_symbol,
                 probe_handler_address,
-                tracepoint_func.prio,
+                prio,
                 module_name,
                 module_address,
             )
@@ -258,11 +270,11 @@ if the "hidden_modules" key is present in known_modules.
         kernel_layer = self.context.layers[kernel.layer_name]
 
         if not kernel.has_symbol("__start___tracepoints_ptrs"):
-            raise exceptions.SymbolError(
-                "__start___tracepoints_ptrs",
-                self.vmlinux.symbol_table_name,
-                'The provided symbol table does not include the "__start___tracepoints_ptrs" symbol. This means you are either analyzing an unsupported kernel version or that your symbol table is corrupted.',
+            vollog.error(
+                'The provided symbol table does not include the "__start___tracepoints_ptrs" symbol.'
+                "This means you are either analyzing an unsupported kernel version or that your symbol table is corrupted."
             )
+            return
 
         known_modules = modxview.Modxview.run_modules_scanners(
             self.context, kernel_name, run_hidden_modules=False
@@ -281,7 +293,7 @@ if the "hidden_modules" key is present in known_modules.
                     format_hints.Hex(tracepoint_parsed.tracepoint_address),
                     tracepoint_parsed.probe_name or NotAvailableValue(),
                     format_hints.Hex(tracepoint_parsed.probe_address),
-                    tracepoint_parsed.probe_priority,
+                    tracepoint_parsed.probe_priority or NotAvailableValue(),
                     tracepoint_parsed.module_name or NotAvailableValue(),
                     (
                         format_hints.Hex(tracepoint_parsed.module_address)