/usr/lib/python2.7/dist-packages/rekall/plugins/addrspaces/elfcore.py is in python-rekall-core 1.6.0+dfsg-2.
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 2012 Philippe Teuwen, Thorsten Sick, Michael Cohen
# Copyright 2013 Google Inc. All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or (at
# your option) any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
"""An Address Space for processing ELF64 coredumps."""
# References:
# VirtualBox core format:
# http://www.virtualbox.org/manual/ch12.html#guestcoreformat
# ELF64 format: http://downloads.openwatcom.org/ftp/devel/docs/elf-64-gen.pdf
# Note that as of version 1.6.0 WinPmem also uses ELF64 as the default imaging
# format. Except that WinPmem stores image metadata in a YAML file stored in the
# image. This address space supports both formats.
import os
import yaml
from rekall import addrspace
from rekall import constants
from rekall.plugins.addrspaces import standard
from rekall.plugins.overlays.linux import elf
PT_PMEM_METADATA = 0x6d656d70 # Spells 'pmem'
class Elf64CoreDump(addrspace.RunBasedAddressSpace):
"""This AS supports ELF64 coredump format, as used by VirtualBox."""
order = 30
__name = "elf64"
__image = True
def __init__(self, **kwargs):
super(Elf64CoreDump, self).__init__(**kwargs)
# Check the file for sanity.
self.check_file()
self.offset = 0
self.fname = ''
self._metadata = {}
# Now parse the ELF file.
elf_profile = elf.ELFProfile(session=self.session)
self.elf64_hdr = elf_profile.elf64_hdr(vm=self.base, offset=0)
self.as_assert(self.elf64_hdr.e_type == "ET_CORE",
"Elf file is not a core file.")
self.name = "%s|%s" % (self.__class__.__name__, self.base.name)
# Iterate over all the program headers and map the runs.
for segment in self.elf64_hdr.e_phoff:
if segment.p_type == "PT_LOAD":
# Some load segments are empty.
if (segment.p_filesz == 0 or
segment.p_filesz != segment.p_memsz):
continue
# Add the run to the memory map.
virtual_address = int(segment.p_paddr) or int(segment.p_vaddr)
self.add_run(virtual_address, # Virtual Addr
int(segment.p_offset), # File Addr
int(segment.p_memsz)) # Run end.
elif segment.p_type == PT_PMEM_METADATA:
self.LoadMetadata(segment.p_offset)
# NOTE: Deprecated! This will be removed soon. If you want to store
# metadata use AFF4 format.
# Search for the pmem footer signature.
footer = self.base.read(self.base.end() - 10000, 10000)
if "...\n" in footer[-6:]:
header_offset = footer.rfind("# PMEM")
if header_offset > 0:
self.LoadMetadata(self.base.end() - 10000 + header_offset)
def check_file(self):
"""Checks the base file handle for sanity."""
self.as_assert(self.base,
"Must stack on another address space")
## Must start with the magic for elf
self.as_assert((self.base.read(0, 4) == "\177ELF"),
"Header signature invalid")
def LoadMetadata(self, offset):
"""Load the WinPmem metadata from the elf file."""
self.session.logging.error(
"DEPRECATED Elf metadata found! "
"This will not be supported in the next release.")
try:
data = self.base.read(offset, 1024*1024)
yaml_file = data.split('...\n')[0]
metadata = yaml.safe_load(yaml_file)
except (yaml.YAMLError, TypeError) as e:
self.session.logging.error(
"Invalid file metadata, skipping: %s" % e)
return
for session_param, metadata_key in (("dtb", "CR3"),
("kernel_base", "KernBase")):
if metadata_key in metadata:
self.session.SetParameter(
session_param, metadata[metadata_key])
previous_section = metadata.pop("PreviousHeader", None)
if previous_section is not None:
self.LoadMetadata(previous_section)
pagefile_offset = metadata.get("PagefileOffset", None)
pagefile_size = metadata.get("PagefileSize", None)
if pagefile_offset is not None and pagefile_size is not None:
self.LoadPageFile(pagefile_offset, pagefile_size)
self._metadata.update(metadata)
pagefile_offset = 0
pagefile_end = 0
def LoadPageFile(self, pagefile_offset, pagefile_size):
"""We map the page file into the physical address space.
This allows us to treat all physical addresses equally - regardless if
they come from the memory or the page file.
"""
# Map the pagefile after the end of the physical address space.
vaddr = self.end() + 0x10000
self.session.logging.info(
"Loading pagefile into physical offset %#08x", vaddr)
# Map the pagefile into the
self.add_run(vaddr, pagefile_offset, pagefile_size)
# Remember the region for the pagefile.
self.pagefile_offset = vaddr
self.pagefile_end = vaddr + pagefile_size
def describe(self, addr):
if self.pagefile_offset <= addr <= self.pagefile_end:
return "%#x@Pagefile" % (
addr - self.pagefile_offset)
return "%#x" % addr
class KCoreAddressSpace(Elf64CoreDump):
"""A Linux kernel's /proc/kcore file also maps the entire physical ram.
http://lxr.free-electrons.com/source/Documentation/x86/x86_64/mm.txt
ffff880000000000 - ffffc7ffffffffff (=64 TB) direct mapping of all
physical memory.
"""
# We must run before the regular Elf64CoreDump address space in the voting
# order.
order = Elf64CoreDump.order - 1
__name = "elf64"
__image = True
def __init__(self, **kwargs):
super(KCoreAddressSpace, self).__init__(**kwargs)
# This is a live address space.
self.volatile = True
self.mapped_files = {}
# Collect all ranges between 0xffff880000000000 - 0xffffc7ffffffffff
runs = []
for start, _, run in self.runs:
if 0xffff880000000000 < run.start < 0xffffc7ffffffffff:
runs.append((start - 0xffff880000000000,
run.file_offset, run.length))
self.as_assert(runs, "No kcore compatible virtual ranges.")
self.runs.clear()
# At this point, we think this is a valid, usable kcore file.
# RHEL, however, disabled read access to /proc/kcore past the ELF
# headers and the file size reflects this. /proc/kcore usually has a
# size of at least 64TB (46bits of physical address space in x64).
# We use the file size to detect cases where kcore will be unusable.
if getattr(self.base, "fhandle", None):
try:
statinfo = os.fstat(self.base.fhandle.fileno())
if statinfo.st_size < 2**46:
# We raise a TypeError and not an ASAssertionError because
# we need it to be catchable when rekall is used as a
# library (i.e GRR). ASAssertionErrors are swallowed by
# the address space selection algorithm.
raise RuntimeError(
"This kcore file is too small (%d bytes) and likely "
"invalid for memory analysis. You may want to use pmem "
"instead." % statinfo.st_size)
except(IOError, AttributeError):
pass
for x in runs:
self.add_run(*x)
def get_file_address_space(self, filename):
try:
# Try to read the file with OS APIs.
return standard.FileAddressSpace(filename=filename,
session=self.session)
except IOError:
return
def WriteElfFile(address_space, outfd, session=None):
"""Convert the address_space to an ELF Core dump file.
The Core dump will be written to outfd which is expected to have a .write()
method.
"""
runs = list(address_space.get_mappings())
elf_profile = elf.ELFProfile(session=session)
elf64_pheader = elf_profile.elf64_phdr()
elf64_pheader.p_type = "PT_LOAD"
elf64_pheader.p_align = 0x1000
elf64_pheader.p_flags = "PF_R"
elf64_header = elf_profile.elf64_hdr()
elf64_header.e_ident = elf64_header.e_ident.signature
elf64_header.e_type = 'ET_CORE'
elf64_header.e_phoff = elf64_header.obj_end
elf64_header.e_ehsize = elf64_header.obj_size
elf64_header.e_phentsize = elf64_pheader.obj_size
elf64_header.e_phnum = len(runs)
elf64_header.e_shnum = 0 # We don't have any sections.
# Where we start writing data.
file_offset = (elf64_header.obj_size +
# One Phdr for each run.
len(runs) * elf64_pheader.obj_size)
outfd.write(elf64_header.GetData())
for run in runs:
elf64_pheader.p_paddr = run.start
elf64_pheader.p_memsz = run.length
elf64_pheader.p_offset = file_offset
elf64_pheader.p_filesz = run.length
outfd.write(elf64_pheader.GetData())
file_offset += run.length
# Now just copy all the runs
total_data = 0
for run in runs:
offset = run.start
length = run.length
while length > 0:
data = address_space.read(offset, min(10000000, length))
session.report_progress("Writing %sMb", total_data/1024/1024)
outfd.write(data)
length -= len(data)
offset += len(data)
total_data += len(data)
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