mirror of
https://github.com/volatilityfoundation/volatility3.git
synced 2026-08-22 22:32:22 +02:00
Mike Auty
5362e2094e
Context.object accepts a template or a string name (and now a type flag). Module.object only accepts a string (because a template already has most of the stuff built in and might as well be passed to the Context.object constructor). The gotcha here is the absolute flag, which must now be set appropriately in all cases *except* where the module is constructed with an offset of 0 (whereby it will have no impact).
199 lines
7.7 KiB
Python
199 lines
7.7 KiB
Python
# This file was contributed to the Volatility Framework Version 3.
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# Copyright (C) 2018 Volatility Foundation.
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#
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# THE LICENSED WORK IS PROVIDED UNDER THE TERMS OF THE Volatility Contributors
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# Public License V1.0("LICENSE") AS FIRST COMPLETED BY: Volatility Foundation,
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# Inc. ANY USE, PUBLIC DISPLAY, PUBLIC PERFORMANCE, REPRODUCTION OR DISTRIBUTION
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# OF, OR PREPARATION OF SUBSEQUENT WORKS, DERIVATIVE WORKS OR DERIVED WORKS BASED
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# ON, THE LICENSED WORK CONSTITUTES RECIPIENT'S ACCEPTANCE OF THIS LICENSE AND ITS
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# TERMS, WHETHER OR NOT SUCH RECIPIENT READS THE TERMS OF THE LICENSE. "LICENSED
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# WORK,” “RECIPIENT" AND “DISTRIBUTOR" ARE DEFINED IN THE LICENSE. A COPY OF THE
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# LICENSE IS LOCATED IN THE TEXT FILE ENTITLED "LICENSE.txt" ACCOMPANYING THE
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# CONTENTS OF THIS FILE. IF A COPY OF THE LICENSE DOES NOT ACCOMPANY THIS FILE, A
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# COPY OF THE LICENSE MAY ALSO BE OBTAINED AT THE FOLLOWING WEB SITE:
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# https://www.volatilityfoundation.org/license/vcpl_v1.0
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#
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# Software distributed under the License is distributed on an "AS IS" basis,
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# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the
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# specific language governing rights and limitations under the License.
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#
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"""A module containing a collection of plugins that produce data
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typically found in Linux's /proc file system.
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"""
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import logging
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from typing import List
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from volatility.framework import exceptions, interfaces, contexts
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from volatility.framework import renderers, constants
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from volatility.framework.automagic import linux
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from volatility.framework.configuration import requirements
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from volatility.framework.interfaces import plugins
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from volatility.framework.renderers import format_hints
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vollog = logging.getLogger(__name__)
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try:
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import capstone
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has_capstone = True
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except ImportError:
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has_capstone = False
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class Check_syscall(plugins.PluginInterface):
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"""Check system call table for hooks"""
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@classmethod
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def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
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return [
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requirements.TranslationLayerRequirement(
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name = 'primary', description = 'Memory layer for the kernel', architectures = ["Intel32", "Intel64"]),
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requirements.SymbolTableRequirement(name = "vmlinux", description = "Linux kernel symbols")
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]
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def _get_table_size_next_symbol(self, table_addr, ptr_sz, vmlinux):
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"""
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Returns the size of the table based on the next symbol
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"""
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ret = 0
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sym_table = self.context.symbol_space[vmlinux.name]
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sorted_symbols = sorted([(sym_table.get_symbol(sn).address, sn) for sn in sym_table.symbols])
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sym_address = 0
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for tmp_sym_address, sym_name in sorted_symbols:
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if tmp_sym_address > table_addr:
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sym_address = tmp_sym_address
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break
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if sym_address > 0:
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ret = int((sym_address - table_addr) / ptr_sz)
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return ret
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def _get_table_size_meta(self, vmlinux):
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"""
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returns the number of symbols that start with __syscall_meta__
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this is a fast way to determine the number of system calls, but not the most accurate
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"""
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return len(
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[sym for sym in self.context.symbol_space[vmlinux.name].symbols if sym.startswith("__syscall_meta__")])
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def _get_table_info_other(self, table_addr, ptr_sz, vmlinux):
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table_size_meta = self._get_table_size_meta(vmlinux)
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table_size_syms = self._get_table_size_next_symbol(table_addr, ptr_sz, vmlinux)
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sizes = [size for size in [table_size_meta, table_size_syms] if size > 0]
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table_size = min(sizes)
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return table_size
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def _get_table_info_disassembly(self, ptr_sz, vmlinux):
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"""
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Find the size of the system call table by disassembling functions
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that immediately reference it in their first isntruction
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This is in the form 'cmp reg,NR_syscalls'
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"""
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table_size = 0
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if not has_capstone:
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return table_size
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if ptr_sz == 4:
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syscall_entry_func = "sysenter_do_call"
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mode = capstone.CS_MODE_32
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else:
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syscall_entry_func = "system_call_fastpath"
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mode = capstone.CS_MODE_64
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md = capstone.Cs(capstone.CS_ARCH_X86, mode)
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try:
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func_addr = self.context.symbol_space.get_symbol(vmlinux.name + constants.BANG + syscall_entry_func).address
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except exceptions.SymbolError as e:
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# if we can't find the disassemble function then bail and rely on a different method
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return 0
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data = self.context.layers.read(self.config['primary'], func_addr, 6)
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for (address, size, mnemonic, op_str) in md.disasm_lite(data, func_addr):
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if mnemonic == 'CMP':
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table_size = int(op_str.split(",")[1].strip()) & 0xffff
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break
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return table_size
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def _get_table_info(self, vmlinux, table_name, ptr_sz):
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table_sym = self.context.symbol_space.get_symbol(vmlinux.name + constants.BANG + table_name)
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table_size = self._get_table_info_disassembly(ptr_sz, vmlinux)
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if table_size == 0:
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table_size = self._get_table_info_other(table_sym.address, ptr_sz, vmlinux)
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if table_size == 0:
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vollog.error("Unable to get system call table size")
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return 0, 0
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return table_sym.address, table_size
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# TODO - add finding and parsing unistd.h once cached file enumeration is added
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def _generator(self):
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linux.LinuxUtilities.aslr_mask_symbol_table(self.context, self.config['vmlinux'], self.config['primary'])
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vmlinux = contexts.Module(
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self.context, self.config['vmlinux'], self.config['primary'], 0, absolute_symbol_addresses = True)
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ptr_sz = vmlinux.get_type("pointer").size
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if ptr_sz == 4:
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table_name = "32bit"
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else:
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table_name = "64bit"
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try:
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table_info = self._get_table_info(vmlinux, "sys_call_table", ptr_sz)
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except exceptions.SymbolError:
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vollog.error("Unable to find the system call table. Exiting.")
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return
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tables = [(table_name, table_info)]
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# this table is only present on 64 bit systems with 32 bit emulation
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# enabled in order to support 32 bit programs and libraries
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# if the symbol isn't there then the support isn't in the kernel and so we skip it
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try:
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ia32_symbol = self.context.symbol_space.get_symbol(vmlinux.name + constants.BANG + "ia32_sys_call_table")
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except exceptions.SymbolError:
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ia32_symbol = None
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if ia32_symbol != None:
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ia32_info = self._get_table_info(vmlinux, "ia32_sys_call_table", ptr_sz)
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tables.append(("32bit", ia32_info))
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for (table_name, (tableaddr, tblsz)) in tables:
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table = vmlinux.object(
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symbol = "array", subtype = vmlinux.get_type("pointer"), offset = tableaddr, count = tblsz)
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for (i, call_addr) in enumerate(table):
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if not call_addr:
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continue
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symbols = list(self.context.symbol_space.get_symbols_by_location(call_addr))
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if len(symbols) > 0:
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sym_name = str(symbols[0].split(constants.BANG)[1]) if constants.BANG in symbols[0] else \
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str(symbols[0])
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else:
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sym_name = "UNKNOWN"
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yield (0, (format_hints.Hex(tableaddr), table_name, i, format_hints.Hex(call_addr), sym_name))
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def run(self):
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return renderers.TreeGrid([("Table Address", format_hints.Hex), ("Table Name", str), ("Index", int),
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("Handler Address", format_hints.Hex), ("Handler Symbol", str)], self._generator())
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