Revert "Linux: Rename linux.envars to linux.envvars"

This reverts commit d9a365d.

volatility3/framework/plugins/linux/envars.py

@@ -1,12 +1,121 @@
-from volatility3.plugins import envvars
+# This file is Copyright 2022 Volatility Foundation and licensed under the Volatility Software License 1.0
+# which is available at https://www.volatilityfoundation.org/license/vsl-v1.0
+#
+
 import logging
 
+from volatility3.framework import exceptions, renderers
+from volatility3.framework.configuration import requirements
+from volatility3.framework.interfaces import plugins
+from volatility3.framework.objects import utility
+from volatility3.plugins.linux import pslist
+
 vollog = logging.getLogger(__name__)
 
 
-class Envars(envvars.Envvars):
-    def run(self, *args, **kwargs):
-        vollog.warning(
-            "The linux.envars plugin has been renamed to linux.envvars and will only be accessible through the new name in a future release"
+class Envars(plugins.PluginInterface):
+    """Lists processes with their environment variables"""
+
+    _required_framework_version = (2, 0, 0)
+
+    @classmethod
+    def get_requirements(cls):
+        # Since we're calling the plugin, make sure we have the plugin's requirements
+        return [
+            requirements.ModuleRequirement(
+                name="kernel",
+                description="Linux kernel",
+                architectures=["Intel32", "Intel64"],
+            ),
+            requirements.PluginRequirement(
+                name="pslist", plugin=pslist.PsList, version=(2, 0, 0)
+            ),
+            requirements.ListRequirement(
+                name="pid",
+                description="Filter on specific process IDs",
+                element_type=int,
+                optional=True,
+            ),
+        ]
+
+    def _generator(self, tasks):
+        """Generates a listing of processes along with environment variables"""
+
+        # walk the process list and return the envars
+        for task in tasks:
+            pid = task.pid
+
+            # get process name as string
+            name = utility.array_to_string(task.comm)
+
+            # try and get task parent
+            try:
+                ppid = task.parent.pid
+            except exceptions.InvalidAddressException:
+                vollog.debug(
+                    f"Unable to read parent pid for task {pid} {name}, setting ppid to 0."
+                )
+                ppid = 0
+
+            # kernel threads never have an mm as they do not have userland mappings
+            try:
+                mm = task.mm
+            except exceptions.InvalidAddressException:
+                # no mm so cannot get envars
+                vollog.debug(
+                    f"Unable to access mm for task {pid} {name} it is likely a kernel thread, will not extract any envars."
+                )
+                mm = None
+                continue
+
+            # if mm exists attempt to get envars
+            if mm:
+                # get process layer to read envars from
+                proc_layer_name = task.add_process_layer()
+                if proc_layer_name is None:
+                    vollog.debug(
+                        f"Unable to construct process layer for task {pid} {name}, will not extract any envars."
+                    )
+                    continue
+                proc_layer = self.context.layers[proc_layer_name]
+
+                # get the size of the envars with sanity checking
+                envars_size = task.mm.env_end - task.mm.env_start
+                if not (0 < envars_size <= 8192):
+                    vollog.debug(
+                        f"Task {pid} {name} appears to have envars of size {envars_size} bytes which fails the sanity checking, will not extract any envars."
+                    )
+                    continue
+
+                # attempt to read all envars data
+                try:
+                    envar_data = proc_layer.read(task.mm.env_start, envars_size)
+                except exceptions.InvalidAddressException:
+                    vollog.debug(
+                        f"Unable to read full envars for {pid} {name} starting at virtual offset {hex(task.mm.env_start)} for {envars_size} bytes, will not extract any envars."
+                    )
+                    continue
+
+                # parse envar data, envars are null terminated, keys and values are separated by '='
+                envar_data = envar_data.rstrip(b"\x00")
+                for envar_pair in envar_data.split(b"\x00"):
+                    try:
+                        key, value = envar_pair.decode().split("=", 1)
+                    except ValueError:
+                        vollog.debug(
+                            f"Unable to extract envars for {pid} {name} starting at virtual offset {hex(task.mm.env_start)}, they don't appear to be '=' separated"
+                        )
+                        continue
+                    yield (0, (pid, ppid, name, key, value))
+
+    def run(self):
+        filter_func = pslist.PsList.create_pid_filter(self.config.get("pid", None))
+
+        return renderers.TreeGrid(
+            [("PID", int), ("PPID", int), ("COMM", str), ("KEY", str), ("VALUE", str)],
+            self._generator(
+                pslist.PsList.list_tasks(
+                    self.context, self.config["kernel"], filter_func=filter_func
+                )
+            ),
         )
-        return super().run(*args, **kwargs)