/usr/lib/python2.7/dist-packages/volatility/plugins/linux/check_inline_kernel.py is in volatility 2.4-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# Copyright (C) 2007-2013 Volatility Foundation
#
# This file is part of Volatility.
#
# Volatility is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License Version 2 as
# published by the Free Software Foundation. You may not use, modify or
# distribute this program under any other version of the GNU General
# Public License.
#
# Volatility is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Volatility. If not, see <http://www.gnu.org/licenses/>.
#
"""
@author: Andrew Case
@license: GNU General Public License 2.0
@contact: atcuno@gmail.com
@organization:
"""
import volatility.obj as obj
import volatility.debug as debug
import volatility.plugins.linux.common as linux_common
import volatility.plugins.linux.lsmod as linux_lsmod
### TODO: merge with check_fops
import volatility.plugins.linux.pslist as linux_pslist
from volatility.plugins.linux.slab_info import linux_slabinfo
import volatility.plugins.linux.find_file as find_file
try:
import distorm3
has_distorm3 = True
except ImportError:
has_distorm3 = False
class linux_check_inline_kernel(linux_common.AbstractLinuxCommand):
"""Check for inline kernel hooks"""
def __init__(self, config, *args, **kwargs):
linux_common.AbstractLinuxCommand.__init__(self, config, *args, **kwargs)
def _is_hooked(self, sym_addr, modules):
hook_type = None
addr = None
counter = 1
prev_op = None
'''
if sym_addr != 0xffffffff8114001d:
return None
'''
if self.profile.metadata.get('memory_model', '32bit') == '32bit':
mode = distorm3.Decode32Bits
else:
mode = distorm3.Decode64Bits
data = self.addr_space.read(sym_addr, 16)
for op in distorm3.Decompose(sym_addr, data, mode):
if not op.valid:
continue
if op.mnemonic == "JMP" and not self.is_known_address(op.operands[0].value, modules):
hook_type = "JMP"
addr = 0 # default in case we cannot extract
# check for a mov reg, addr; jmp reg;
if prev_op.mnemonic == "MOV" and prev_op.operands[0].type == 'Register' and op.operands[0].type == 'Register':
prev_name = prev_op.operands[0].name
# same register
if prev_name == op.operands[0].name:
addr = prev_op.operands[1].value
elif op.mnemonic == "CALL" and not self.is_known_address(op.operands[0].value, modules):
hook_type = "CALL"
addr = op.operands[0].value
# push xxxx; ret;
elif counter == 2 and op.mnemonic == "RET":
if prev_op.mnemonic == "MOV" and prev_op.operands[0].type == 'Register' and prev_op.operands[0].name in ["RAX", "EAX"]:
break
elif prev_op.mnemonic == "XOR" and prev_op.operands[0].type == 'Register' and prev_op.operands[1].type == 'Register':
break
elif prev_op.mnemonic == "MOV" and prev_op.operands[0].type == 'Register' and prev_op.operands[1].type == 'Register':
break
hook_type = "RET"
addr = sym_addr
if hook_type:
break
counter = counter + 1
if counter == 4:
break
prev_op = op
if hook_type:
ret = hook_type, addr
else:
ret = None
return ret
#### make api with check_fops
def _is_inline_hooked(self, ops, op_members, modules):
for check in op_members:
addr = ops.m(check)
if addr and addr != 0:
hook_info = self._is_hooked(addr, modules)
if hook_info:
(hook_type, addr) = hook_info
yield check, hook_type, addr
def check_file_cache(self, f_op_members, modules):
for (_, _, file_path, file_dentry) in find_file.linux_find_file(self._config).walk_sbs():
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(file_dentry.d_inode.i_fop, f_op_members, modules):
yield (file_path, hooked_member, hook_type, hook_address)
def check_open_files_fop(self, f_op_members, modules):
# get all the members in file_operations, they are all function pointers
tasks = linux_pslist.linux_pslist(self._config).calculate()
for task in tasks:
for filp, i in task.lsof():
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(filp.f_op, f_op_members, modules):
name = "{0:s} {1:d} {2:s}".format(task.comm, i, linux_common.get_path(task, filp))
yield (name, hooked_member, hook_type, hook_address)
def check_proc_fop(self, f_op_members, modules):
proc_mnt_addr = self.addr_space.profile.get_symbol("proc_mnt")
if not proc_mnt_addr:
return
proc_mnt_ptr = obj.Object("Pointer", offset = proc_mnt_addr, vm = self.addr_space)
proc_mnt = proc_mnt_ptr.dereference_as("vfsmount")
root = proc_mnt.mnt_root
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(root.d_inode.i_fop, f_op_members, modules):
yield ("proc_mnt: root", hooked_member, hook_type, hook_address)
# only check the root directory
for dentry in root.d_subdirs.list_of_type("dentry", "d_u"):
name = dentry.d_name.name.dereference_as("String", length = 255)
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(dentry.d_inode.i_fop, f_op_members, modules):
yield("proc_mnt: {0}".format(name), hooked_member, hook_type, hook_address)
def walk_proc(self, cur, f_op_members, modules, parent = ""):
while cur:
if cur.obj_offset in self.seen_proc:
cur = cur.next
continue
self.seen_proc[cur.obj_offset] = 1
name = parent + "/" + self.addr_space.read(cur.name.obj_offset, cur.namelen + 1)
idx = name.find("\x00")
if idx != -1:
name = name[:idx]
fops = cur.proc_fops
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(fops, f_op_members, modules):
yield (name, hooked_member, hook_type, hook_address)
subdir = cur.subdir
while subdir:
for (sub_name, hooked_member, hook_type, hook_address) in self.walk_proc(subdir, f_op_members, modules, name):
yield (sub_name, hooked_member, hook_type, hook_address)
subdir = subdir.next
cur = cur.next
def check_proc_root_fops(self, f_op_members, modules):
self.seen_proc = {}
proc_root_addr = self.addr_space.profile.get_symbol("proc_root")
proc_root = obj.Object("proc_dir_entry", offset = proc_root_addr, vm = self.addr_space)
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(proc_root.proc_fops, f_op_members, modules):
yield("proc_root", hooked_member, hook_type, hook_address)
for (name, hooked_member, hook_type, hook_address) in self.walk_proc(proc_root, f_op_members, modules):
yield (name, hooked_member, hook_type, hook_address)
#### end make api with check_fops
def _check_file_op_pointers(self, modules):
funcs = [self.check_open_files_fop, self.check_proc_fop, self.check_proc_root_fops, self.check_file_cache]
f_op_members = self.profile.types['file_operations'].keywords["members"].keys()
f_op_members.remove('owner')
for func in funcs:
for (name, member, hook_type, address) in func(f_op_members, modules):
yield (name, member, hook_type, address)
def check_afinfo(self, var_name, var, op_members, seq_members, modules):
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(var.seq_fops, op_members, modules):
yield (var_name, hooked_member, hook_type, hook_address)
# newer kernels
if hasattr(var, "seq_ops"):
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(var.seq_ops, seq_members, modules):
yield (var_name, hooked_member, hook_type, hook_address)
def _check_afinfo(self, modules):
op_members = self.profile.types['file_operations'].keywords["members"].keys()
seq_members = self.profile.types['seq_operations'].keywords["members"].keys()
tcp = ("tcp_seq_afinfo", ["tcp6_seq_afinfo", "tcp4_seq_afinfo"])
udp = ("udp_seq_afinfo", ["udplite6_seq_afinfo", "udp6_seq_afinfo", "udplite4_seq_afinfo", "udp4_seq_afinfo"])
protocols = [tcp, udp]
for proto in protocols:
struct_type = proto[0]
for global_var_name in proto[1]:
global_var_addr = self.addr_space.profile.get_symbol(global_var_name)
if not global_var_addr:
continue
global_var = obj.Object(struct_type, offset = global_var_addr, vm = self.addr_space)
for (name, member, hook_type, address) in self.check_afinfo(global_var_name, global_var, op_members, seq_members, modules):
yield (name, member, hook_type, address)
def _check_inetsw(self, modules):
try:
self.addr_space.profile.get_obj_offset("inet_protosw", "list")
except KeyError:
debug.warning("You are using an old Linux profile. Please recreate the profile using the latest Volatility version.")
return
proto_members = self.profile.types['proto_ops'].keywords["members"].keys()
proto_members.remove('owner')
proto_members.remove('family')
inetsw_addr = self.addr_space.profile.get_symbol("inetsw")
inetsw = obj.Object(theType = "Array", targetType = "list_head", offset = inetsw_addr, vm = self.addr_space, count = 11)
for inet_list in inetsw:
for inet in inet_list.list_of_type("inet_protosw", "list"):
name = self.addr_space.read(inet.prot.name.obj_offset, 32)
idx = name.index("\x00")
if idx != -1:
name = name[:idx]
for (hooked_member, hook_type, hook_address) in self._is_inline_hooked(inet.ops, proto_members, modules):
yield (name, hooked_member, hook_type, hook_address)
def _check_known_functions(self, modules):
known_funcs = ["dev_get_flags", "vfs_readdir", "tcp_sendmsg"]
for func_name in known_funcs:
func_addr = self.profile.get_symbol(func_name)
if func_addr:
hook_info = self._is_hooked(func_addr, modules)
if hook_info:
(hook_type, hook_address) = hook_info
yield (func_name, "", hook_type, hook_address)
def calculate(self):
linux_common.set_plugin_members(self)
if not has_distorm3:
debug.error("This plugin cannot operate without distrom installed.")
modules = linux_lsmod.linux_lsmod(self._config).get_modules()
funcs = [self._check_known_functions, self._check_file_op_pointers, self._check_afinfo, self._check_inetsw]
for func in funcs:
for (sym_name, member, hook_type, sym_addr) in func(modules):
yield (sym_name, member, hook_type, sym_addr)
def render_text(self, outfd, data):
self.table_header(outfd, [("Name", "48"),
("Member", "16"),
("Hook Type", "8"),
("Hook Address", "[addrpad]")])
for (sym_name, member, hook_type, sym_addr) in data:
self.table_row(outfd, sym_name, member, hook_type, sym_addr)
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