# This file is Copyright 2024 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 interfaces, renderers, exceptions
from volatility3.framework.configuration import requirements
from volatility3.framework.objects import utility
vollog = logging.getLogger(__name__)
[docs]class Dmesg(interfaces.plugins.PluginInterface):
"""Prints the kernel log buffer."""
_required_framework_version = (2, 0, 0)
_version = (1, 0, 0)
[docs] @classmethod
def get_requirements(cls):
return [
requirements.ModuleRequirement(
name="kernel",
description="Kernel module for the OS",
architectures=["Intel32", "Intel64"],
),
]
[docs] @classmethod
def get_kernel_log_buffer(
cls, context: interfaces.context.ContextInterface, kernel_module_name: str
):
"""
Online documentation :
- https://github.com/apple-open-source/macos/blob/master/xnu/bsd/sys/msgbuf.h
- https://github.com/apple-open-source/macos/blob/ea4cd5a06831aca49e33df829d2976d6de5316ec/xnu/bsd/kern/subr_log.c#L751
Volatility 2 plugin :
- https://github.com/volatilityfoundation/volatility/blob/master/volatility/plugins/mac/dmesg.py
"""
kernel = context.modules[kernel_module_name]
if not kernel.has_symbol("msgbufp"):
raise exceptions.SymbolError(
"msgbufp",
kernel.symbol_table_name,
'The provided symbol table does not include the "msgbufp" symbol. This means you are either analyzing an unsupported kernel version or that your symbol table is corrupt.',
)
msgbufp = kernel.object_from_symbol(symbol_name="msgbufp")
msg_size = msgbufp.msg_size # max buffer size
msg_bufx = msgbufp.msg_bufx # write index of the msg_bufc circular buffer
msg_bufc = msgbufp.msg_bufc
# msg_bufc is circular, meaning that if its size exceeds msg_size,
# msg_bufx will point to the beginning of the buffer and start overwriting.
msg_bufc_data: str = utility.pointer_to_string(msg_bufc, msg_size)
# Avoid OOB reads
msg_bufx = msg_bufx if msg_bufx <= msg_size else 0
# We directly take into account the case where the write buffer did a loop,
# as older messages will start at msg_bufx offset (not overwritten yet).
dmesg = msg_bufc_data[msg_bufx:]
dmesg += msg_bufc_data[:msg_bufx]
# Yield each line
for dmesg_line in dmesg.splitlines():
yield (dmesg_line,)
def _generator(self):
for value in self.get_kernel_log_buffer(
context=self.context, kernel_module_name=self.config["kernel"]
):
yield (0, value)
[docs] def run(self):
return renderers.TreeGrid(
[
("line", str),
],
self._generator(),
)