Merge pull request #1108 from Abyss-W4tcher/mac_dmesg

macOS dmesg plugin support

volatility3/framework/plugins/mac/dmesg.py

@@ -0,0 +1,79 @@
+# 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__)
+
+
+class Dmesg(interfaces.plugins.PluginInterface):
+    """Prints the kernel log buffer."""
+
+    _required_framework_version = (2, 0, 0)
+    _version = (1, 0, 0)
+
+    @classmethod
+    def get_requirements(cls):
+        return [
+            requirements.ModuleRequirement(
+                name="kernel",
+                description="Kernel module for the OS",
+                architectures=["Intel32", "Intel64"],
+            ),
+        ]
+
+    @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)
+
+    def run(self):
+        return renderers.TreeGrid(
+            [
+                ("line", str),
+            ],
+            self._generator(),
+        )