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peda-arm.py
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peda-arm.py
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#
# PEDA - Python Exploit Development Assistance for GDB
#
# Copyright (C) 2012 Long Le Dinh <longld at vnsecurity.net>
#
# License: see LICENSE file for details
#
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import os
import random
import sys
# point to absolute path of peda.py
PEDAFILE = os.path.abspath(os.path.expanduser(__file__))
while os.path.islink(PEDAFILE):
PEDAFILE = os.path.abspath(os.path.join(os.path.dirname(PEDAFILE), os.path.expanduser(os.readlink(PEDAFILE))))
sys.path.insert(0, os.path.dirname(PEDAFILE))
from peda import *
try:
import zlib
except ImportError:
zlib = None
__version__ = 'alpha-1.0'
class Asm:
"""
Wrapper class for assemble/disassemble using as
"""
def __init__(self):
# Check cross compile toolchains
PREFIXES = "arm-none-eabi- arm-eabi- arm-androideabi- arm-none-linux-gnueabi- arm-linux-androideabi- " \
"arm-linux-android- arm-linux-eabi- arm-linux-gnueabi- arm-linux-gnueabihf-"
prefix = ''
for i in PREFIXES.split():
command = "%sobjdump" % i
if which(command):
prefix = i
break
if prefix == '':
warning('Cross compile toolchain not found! '
'You can install it from https://developer.arm.com/open-source/gnu-toolchain/gnu-rm/downloads')
return
self.PREFIX = prefix
self.READELF = "%sreadelf" % prefix
self.OBJDUMP = "%sobjdump" % prefix
self.OBJCOPY = '%sobjcopy' % prefix
self.AS = '%sas' % prefix
def assemble(self, asmcode, arch='arm'):
"""
Assemble ASM instructions using AS
- asmcode: input ASM instructions, multiple instructions are separated by ";" (String)
- arch: arm / aarch64 / thumb / thumb64 assembly
Returns:
- bin code (raw bytes)
"""
if self.PREFIX == '':
warning('Cross compile toolchain not found! ')
return
# todo aarch64 and thumb64
gas = self.AS
assemblers = {
'arm': gas,
'aarch64': '%s --64' % gas,
'thumb': '%s -mthumb' % gas
}
arch = arch.lower()
if '6' in arch:
arch = 'aarch64'
elif arch.startswith('t'):
arch = 'thumb'
else:
arch = 'arm'
assembler = assemblers[arch]
asmcode = asmcode.strip('"').strip("'")
asmcode = asmcode.replace(";", "\n")
asmcode = decode_string_escape(asmcode)
infd = tmpfile()
elffd = tmpfile(is_binary_file=True)
infd.write(asmcode)
infd.flush()
execute_external_command("%s -o %s %s" % (assembler, elffd.name, infd.name))
infd.close()
if not os.path.exists(elffd.name):
# reopen it so tempfile will not complain
open(elffd.name, 'w').write('B00B')
return None
outfd = tmpfile(is_binary_file=True)
objcopy = '%s -j .text -Obinary %s %s' % (self.OBJCOPY, elffd.name, outfd.name)
execute_external_command(objcopy)
elffd.close()
if not os.path.exists(outfd.name):
# reopen it so tempfile will not complain
open(outfd.name, 'w').write('B00B')
return None
bincode = outfd.read()
outfd.close()
return bincode
def disassemble(self, buf, arch='arm'):
"""
Disassemble binary to ASM instructions using OBJCOPY OBJDUMP
- buf: input binary (raw bytes)
- arch: arm / aarch64 / thumb / thumb64 assembly
Returns:
- ASM code (String)
"""
if self.PREFIX == '':
warning('Cross compile toolchain not found! ')
return
# todo aarch64 and thumb64
if not buf:
return None
rawfd = tmpfile(is_binary_file=True)
elffd = tmpfile(is_binary_file=True)
objdump = [self.OBJDUMP, '-d', '--adjust-vma', '0', '-b', 'elf32-littlearm']
objcopy = [self.OBJCOPY,
'-I', 'binary',
'-O', 'elf32-littlearm',
'-B', 'arm',
'--set-section-flags', '.data=code',
'--rename-section', '.data=.text',
]
if 'thumb' in arch:
objcopy += ['--prefix-symbol=\\$t.']
else:
objcopy += ['-w', '-N', '\\*']
rawfd.write(buf)
rawfd.flush()
execute_external_command(' '.join(objcopy + [rawfd.name, elffd.name]))
out = execute_external_command(' '.join(objdump + [elffd.name]))
out = out.split('<.text>:\n')
if len(out) != 2:
return None
result = out[1].strip('\n').rstrip().expandtabs()
return result
def format_shellcode(self, buf, arch='arm'):
"""
Format raw shellcode to disasm output display
"\x6a\x01" # 0x00000000: push byte +0x1
"\x5b" # 0x00000002: pop ebx
TODO: understand syscall numbers, socket call
"""
if self.PREFIX == '':
warning('Cross compile toolchain not found! ')
return
asmcode = self.disassemble(buf, arch)
if not asmcode:
return ""
shellcode = []
# ' 0: e49df004 pop {pc} ; (ldr pc, [sp], #4)'
pattern = re.compile("\s*([0-9a-f]+):\s*([0-9a-f]+)(.+)")
# matches = pattern.findall(asmcode)
for line in asmcode.splitlines():
m = pattern.match(line)
if m:
(addr, bytes, code) = m.groups()
sc = '"0x%s"' % bytes
shellcode += [(sc, "0x" + addr, code.strip())]
# Define syscall dict {number:[function_name,name,params_num,[params...]]}
SYSTEM_CALLS = None
# Define registers
# REGISTERS = {
# 32: ['r' + str(i) for i in range(13)] + 'sp lr pc'.split(),
# 64: ['x' + str(i) for i in range(31)] + 'sp pc'.split()
# }
CPSRS = {
32: 'N Z C V I F T'.split(),
64: 'N Z C V SS IL D A I F'.split()
}
CPSR_TEXTS = {
32: 'negative zero carry overflow no-irq no-fiq thumb'.split(),
64: 'negative zero carry overflow software-step illegal-execution debug asynchronous-abort no-irq no-fiq'.split()
}
CPSR_N = 1 << 31
CPSR_Z = 1 << 30
CPSR_C = 1 << 29
CPSR_V = 1 << 28
CPSR_SS = 1 << 21
CPSR_IL = 1 << 20
CPSR_D = 1 << 9
CPSR_A = 1 << 8
CPSR_I = 1 << 7
CPSR_F = 1 << 6
CPSR_T = 1 << 5
CPSR_MASKS = {
32: [CPSR_N, CPSR_Z, CPSR_C, CPSR_V, CPSR_I, CPSR_F, CPSR_T],
64: [CPSR_N, CPSR_Z, CPSR_C, CPSR_V, CPSR_SS, CPSR_IL, CPSR_D, CPSR_A, CPSR_I, CPSR_F]
}
CPSR_M_MASKS = {
32: 0b11111,
64: 0b1111
}
CPSR_M_MODES = {
32: {0b10000: 'user', 0b10001: 'fiq', 0b10010: 'irq', 0b10011: 'supervisor', 0b10111: 'abort', 0b11011: 'undefined',
0b11111: 'system'},
64: {0b0000: 'EL0t', 0b0100: 'El1t', 0b0101: 'EL1h', 0b1000: 'EL2t', 0b1001: 'EL2h', 0b1100: 'EL3t', 0b1101: 'EL3h'}
}
# CPSR = ["T", "F", "I", "V", "C", "Z", "N"]
# CPSR_TEXT = ["thumb", "no-fiq", "no-irq", "overflow", "carry", "zero", "negative"]
#
# CPSR_INDEX = [CPSR_T, CPSR_F, CPSR_I, CPSR_V, CPSR_C, CPSR_Z, CPSR_N]
# CPSR_M = 0b11111
# CPSR_M_TEXT = ['user', 'fiq', 'irq', 'supervisor', 'abort', 'undefined', 'system']
# CPSR_M_INDEX = [0b10000, 0b10001, 0b10010, 0b10011, 0b10111, 0b11011, 0b11111]
# CPSR_MODES = dict(zip(CPSR_M_INDEX, CPSR_M_TEXT))
class ArmPEDACmd(PEDACmd):
def _get_function_args_32(self, code, argc=None):
"""
Guess the number of arguments passed to a function - arm
"""
reg_order = ["r0", "r1", "r2", "r3"]
if argc is None:
# deal with regs
p = re.compile(":\s*(\S+)\s*(\w+),")
matches = p.findall(code)
m = [r for (_, r) in matches]
args = []
regs = self.peda.getregs()
for arg in reg_order:
if arg in m:
args.append(regs[arg])
else:
break
if len(args) < 4:
return args
else:
argc = 0
# '0x8d08: str r3, [sp, #20]'
p = re.compile(":\s*str\s*\S+,\s*\[sp.*#(.*)\]")
matches = p.findall(code)
if matches:
l = len(matches)
for v in matches:
# if v.startswith("+"):
offset = to_int(v)
if offset is not None and (offset // 4) > l:
continue
argc += 1
else: # try with push style todo
argc = code.count("push")
argc = min(argc, 6)
if argc == 0:
return args
sp = self.peda.getreg("sp")
mem = self.peda.dumpmem(sp, sp + 4 * argc)
for i in range(argc):
args += [struct.unpack("<L", mem[i * 4:(i + 1) * 4])[0]]
return args
elif to_int(argc) is None:
return None
else:
argc = to_int(argc)
args = []
# deal with regs
regs = self.peda.getregs()
for reg in reg_order:
if argc == 0:
break
args.append(regs[reg])
argc -= 1
if argc == 0:
return args
# deal with mem
sp = self.peda.getreg("sp")
mem = self.peda.dumpmem(sp, sp + 4 * argc)
for i in range(argc):
args += [struct.unpack("<L", mem[i * 4:(i + 1) * 4])[0]]
return args
def _get_function_args_64(self, code, argc=None):
"""
Guess the number of arguments passed to a function - x86_64
"""
return []
def _get_function_args(self, argc=None):
"""
Get the guessed arguments passed to a function when stopped at a call instruction
Args:
- argc: force to get specific number of arguments (Int)
Returns:
- list of arguments (List)
"""
args = []
regs = self.peda.getregs()
if regs is None:
return []
bits = self.peda.getbits()
code = ""
if argc is None:
pc = self.peda.getpc()
prev_insts = self.peda.prev_inst(pc, 12)
if not prev_insts:
return []
for (addr, inst) in prev_insts[::-1]:
if inst.strip().startswith('b'):
break
code = "0x%x:%s\n" % (addr, inst) + code
if bits == 32:
args = self._get_function_args_32(code, argc)
elif bits == 64:
args = self._get_function_args_64(code, argc)
return args
# get_function_args()
def dumpargs(self, *arg):
"""
Display arguments passed to a function when stopped at a call instruction
Usage:
MYNAME [count]
count: force to display "count args" instead of guessing
"""
(count,) = normalize_argv(arg, 1)
if not self._is_running():
return
args = self._get_function_args(count)
if args:
msg("Guessed arguments:")
for (i, a) in enumerate(args):
chain = peda.examine_mem_reference(a)
msg("arg[%d]: %s" % (i, format_reference_chain(chain)))
else:
msg("No argument")
return
# return [function_name,name,params_num,[params...],[params_value...]]
def _get_syscall_args(self, num=None):
if self.peda.getbits() != 32:
# todo
return None
regs = self.peda.getregs()
if regs is None:
return None
r7 = to_int(num)
if r7 is None:
r7 = regs['r7']
if r7 not in SYSTEM_CALLS:
return None
function_name, name, params_num, params = SYSTEM_CALLS[r7]
args = []
# deal with regs
for reg in 'r0 r1 r2 r3 r4 r5 r6'.split():
if params_num == 0:
break
args.append(regs[reg])
params_num -= 1
if params_num != 0:
# deal with mem
sp = self.peda.getreg("sp")
mem = self.peda.dumpmem(sp, sp + 4 * params_num)
for i in range(params_num):
args += [struct.unpack("<L", mem[i * 4:(i + 1) * 4])[0]]
return function_name, name, len(params), params, args
def syscall(self, *arg):
"""
Display information at a system call instruction
Usage:
MYNAME [num]
nun: force to display "system call num" instead of figure out register r7
"""
if SYSTEM_CALLS is None:
return
(num,) = normalize_argv(arg, 1)
if not self._is_running():
return
args = self._get_syscall_args(num)
if args:
function_name, name, params_num, params, args = args
text = [blue('System call:', 'bold'),
' %s' % function_name,
blue('Description:', 'bold'),
' %s' % name,
blue("Arguments:", 'bold')]
if params_num == 0:
text.append(' Argument None')
else:
for i in range(params_num):
chain = peda.examine_mem_reference(args[i])
text.append(" arg[%d]:(%s) %s" % (i, params[i], format_reference_chain(chain)))
text = '\n'.join(text)
msg(text)
else:
msg(" System call not found!")
return
def syscall_detail(self, *arg):
"""
Display details at a system call instruction
Usage:
MYNAME num | syscall_name
num: force to display "system call num" instead of figure out register r7
"""
if SYSTEM_CALLS is None:
return
(num,) = normalize_argv(arg, 1)
if num is None:
self._missing_argument()
if to_int(num) is not None:
func_name = SYSTEM_CALLS[to_int(num)][0]
else:
func_name = num
peda.execute('shell man 2 %s' % func_name)
# wrapper for stepuntil("j")
def nextjmp(self, *arg):
"""
Step until next 'j*' instruction in specific memory range
Usage:
MYNAME [keyword] [mapname1,mapname2]
"""
(keyword, mapname) = normalize_argv(arg, 2)
if keyword:
self.stepuntil("b.*%s" % keyword, mapname)
else:
self.stepuntil("b", mapname)
def _testjump(self, inst=None):
"""
Test if jump instruction is taken or not
Returns:
- (status, address of target jumped instruction)
"""
flags = self._get_cpsr()
if not flags:
return None
if not inst:
pc = self.peda.getpc()
inst = self.peda.execute_redirect("x/i 0x%x" % pc)
if not inst:
return None
# inst='=> 0x8b84 <_start+40>:\tblxeq.n\t0xa3bc <__libc_start_main>'
match = re.match('.*:\s+(b[l|x]{0,2})(\S{0}|\S{2})(\.w|\.n)?\s+', inst)
next_addr = self.peda.eval_target(inst)
if next_addr is None:
next_addr = 0
if not match:
return None
cond = match.group(2)
if (
cond == ''
) or (
cond == 'al'
) or (
cond == "eq" and flags["Z"]
) or (
cond == "ne" and not flags["Z"]
) or (
(cond == 'cs' or cond == 'hs') and flags['C']
) or (
(cond == 'cc' or cond == 'lo') and not flags['C']
) or (
cond == 'mi' and flags['N']
) or (
cond == 'pl' and not flags['N']
) or (
cond == 'vs' and flags['V']
) or (
cond == 'vc' and not flags['V']
) or (
cond == 'hi' and flags['C'] and not flags['Z']
) or (
cond == 'ls' and (not flags['C'] or flags['Z'])
) or (
cond == 'ge' and (flags['Z'] or flags['N'] == flags['V'])
) or (
cond == 'lt' and not flags['Z'] and flags['N'] != flags['V']
) or (
cond == 'gt' and not flags['Z'] and flags['N'] == flags['V']
) or (
cond == 'le' and (flags['Z'] or flags['N'] != flags['V'])
):
return next_addr
else:
return None
def _testjump_cb(self, inst=None):
"""
Test if jump instruction for `cb` is taken or not
Returns:
- (status, address of target jumped instruction)
"""
flags = self._get_cpsr()
if not flags:
return None
if not inst:
pc = self.peda.getpc()
inst = self.peda.execute_redirect("x/i 0x%x" % pc)
if not inst:
return None
# inst='=> 0xaf130bd4:\tcbz\tr0, 0xaf130be4'
match = re.match('.*:\s+cb(n?z)?\s+(\S+),\s*(\S+)', inst)
if not match:
return None
cond, r, next_addr = match.groups()
r = self.peda.parse_and_eval(r)
r = to_int(r)
if r is None:
return None
next_addr = self.peda.parse_and_eval(next_addr)
next_addr = to_int(next_addr)
if next_addr is None:
next_addr = 0
if (
cond == 'z' and r == 0
) or (
cond == 'nz' and r != 0
):
return next_addr
else:
return None
@msg.bufferize
def context_code(self, *arg):
"""
Display nearby disassembly at $PC of current execution context
Usage:
MYNAME [linecount]
"""
(count,) = normalize_argv(arg, 1)
if count is None:
count = 8
if not self._is_running():
return
peda = self.peda
pc = peda.getpc()
if peda.is_address(pc):
inst = peda.get_disasm(pc)
else:
inst = None
text = blue("[%s]" % "CODE".center(self.width, "-"))
msg(text)
if inst: # valid $PC
text = ""
opcode = inst.split(":\t")[-1].split()[0]
if opcode.startswith('b'):
jumpto = self._testjump(inst)
if jumpto: # JUMP is taken
code = peda.disassemble_around(pc, count)
code = code.splitlines()
pc_idx = 999
for (idx, line) in enumerate(code):
if ("0x%x" % pc) in line.split(":")[0]:
pc_idx = idx
if idx <= pc_idx:
text += line + "\n"
else:
text += " | %s\n" % line.strip()
text = format_disasm_code_arm(text, pc) + "\n"
text += " |->"
if 'x' in opcode:
current_mode = peda.execute_redirect('show arm force-mode')
match = re.search(r'"(\S*)"', current_mode)
if match:
current_mode = match.group(1)
else:
current_mode = 'auto'
peda.execute_redirect('set arm force-mode %s' % ('thumb' if jumpto & 0x1 else 'arm'))
code = peda.get_disasm(jumpto, count // 2)
peda.execute_redirect('set arm force-mode %s' % current_mode)
else:
code = peda.get_disasm(jumpto, count // 2)
if not code:
code = " Cannot evaluate jump destination\n"
code = code.splitlines()
text += red(code[0]) + "\n"
for line in code[1:]:
text += " %s\n" % line.strip()
text += red("JUMP is taken".rjust(self.width))
msg(text.rstrip())
self.dumpargs()
else: # JUMP is NOT taken
text += format_disasm_code_arm(peda.disassemble_around(pc, count), pc)
text += "\n" + green("JUMP is NOT taken".rjust(self.width))
msg(text.rstrip())
elif opcode.startswith('cb'):
jumpto = self._testjump_cb(inst)
if jumpto: # JUMP is taken
code = peda.disassemble_around(pc, count)
code = code.splitlines()
pc_idx = 999
for (idx, line) in enumerate(code):
if ("0x%x" % pc) in line.split(":")[0]:
pc_idx = idx
if idx <= pc_idx:
text += line + "\n"
else:
text += " | %s\n" % line.strip()
text = format_disasm_code_arm(text, pc) + "\n"
text += " |->"
code = peda.get_disasm(jumpto, count // 2)
if not code:
code = " Cannot evaluate jump destination\n"
code = code.splitlines()
text += red(code[0]) + "\n"
for line in code[1:]:
text += " %s\n" % line.strip()
text += red("JUMP is taken".rjust(self.width))
msg(text.rstrip())
else: # JUMP is NOT taken
text += format_disasm_code_arm(peda.disassemble_around(pc, count), pc)
text += "\n" + green("JUMP is NOT taken".rjust(self.width))
msg(text.rstrip())
# stopped at other instructions
else:
text += peda.disassemble_around(pc, count)
msg(format_disasm_code_arm(text, pc))
if 'svc' in opcode:
msg('')
self.syscall()
else: # invalid $PC
msg("Invalid $PC address: 0x%x" % pc, "red")
return
def _get_cpsr(self):
"""
Get flags value from CPSR register
Returns:
- dictionary of named flags
"""
# need indeed
cpsr = self.peda.getreg("cpsr")
# if not cpsr:
# return None
bits = self.peda.getbits()
CPSR = CPSRS[bits]
CPSR_MASK = CPSR_MASKS[bits]
flags = {}
for i in range(len(CPSR)):
flags[CPSR[i]] = bool(cpsr & CPSR_MASK[i])
return flags
def _get_mode(self):
cpsr = self.peda.getreg("cpsr")
if not cpsr:
return None
bits = self.peda.getbits()
mode = cpsr & CPSR_M_MASKS[bits]
CPSR_MODES = CPSR_M_MODES[bits]
if mode in CPSR_MODES:
return CPSR_MODES[mode].upper()
else:
return None
def _set_cpsr(self, flagname, value):
"""
Set/clear/toggle value of a flag register
Returns:
- True if success (Bool)
"""
# like above
cpsr = self._get_cpsr()
if not cpsr:
return False
bits = self.peda.getbits()
CPSR = CPSRS[bits]
CPSR_TEXT = CPSR_TEXTS[bits]
CPSR_MASK = CPSR_MASKS[bits]
if flagname.upper() in CPSR:
index = CPSR.index(flagname.upper())
elif flagname.lower() in CPSR_TEXT:
index = CPSR_TEXT.index(flagname.lower())
else:
return False
if value is None or cpsr[CPSR[index]] != value: # switch value
reg_cpsr = self.peda.getreg("cpsr")
reg_cpsr ^= CPSR_MASK[index]
result = self.peda.execute("set $cpsr = 0x%x" % reg_cpsr)
return result
return True
def cpsr(self, *arg):
"""
Display/set/clear value of cpsr register
Usage:
MYNAME
MYNAME [set|clear] flagname
MYNAME [set|clear|toggle] flagname
"""
(option, flagname) = normalize_argv(arg, 2)
if not self._is_running():
return
if option and not flagname:
self._missing_argument()
if option is None: # display cpsr
bits = self.peda.getbits()
CPSR = CPSRS[bits]
CPSR_TEXT = CPSR_TEXTS[bits]
text = []
flags = self._get_cpsr()
for (i, f) in enumerate(CPSR):
if flags[f]:
text.append(red(CPSR_TEXT[i].upper(), "bold"))
else:
text.append(green(CPSR_TEXT[i].lower()))
text.append(blue("[%s-MODE]" % self._get_mode()))
text = ' '.join(text)
cpsr = peda.getreg("cpsr")
msg("%s: 0x%x (%s)" % (green("CPSR"), cpsr, text))
elif option == "set":
self._set_cpsr(flagname.lower(), True)
elif option == "clear":
self._set_cpsr(flagname, False)
elif option == 'toggle':
self._set_cpsr(flagname, None)
cpsr.options = ["set", "clear"]
def xinfo(self, *arg):
"""
Display detail information of address/registers
Usage:
MYNAME address
MYNAME register [reg1 reg2]
"""
(address, regname) = normalize_argv(arg, 2)
if address is None:
self._missing_argument()
super(ArmPEDACmd, self).xinfo(*arg)
if str(address).startswith("r"):
if regname is None or "cpsr" in regname:
self.cpsr()
xinfo.options = ["register"]
###############################
# Exploit Helper Commands #
###############################
@memoized
def _assemble(self, asmcode, arch=None):
"""
Assemble ASM instructions using NASM
- asmcode: input ASM instructions, multiple instructions are separated by ";" (String)
Returns:
- bin code (raw bytes)
"""
if arch is None:
bits = self.peda.getbits()
arch = 'arm' if bits == 32 else 'aarch64'
return asm.assemble(asmcode, arch)
# cyclic_pattern()
def pattern_create(self, *arg):
"""
Generate a cyclic pattern
Set "pattern" option for basic/extended pattern type
Usage:
MYNAME size [file]
"""
(size, filename) = normalize_argv(arg, 2)
if size is None:
self._missing_argument()
pattern = cyclic_pattern(size)
if filename is not None:
open(filename, "wb").write(pattern)
msg("Writing pattern of %d chars to filename \"%s\"" % (len(pattern), filename))
else:
msg("'" + pattern.decode('utf-8') + "'")
return
# cyclic_pattern()
def pattern_offset(self, *arg):
"""
Search for offset of a value in cyclic pattern
Set "pattern" option for basic/extended pattern type
Usage:
MYNAME value
"""
(value,) = normalize_argv(arg, 1)
if value is None:
self._missing_argument()
pos = cyclic_pattern_offset(value)
if pos is None:
msg("%s not found in pattern buffer" % value)
else:
msg("%s found at offset: %d" % (value, pos))
return
# cyclic_pattern(), searchmem_*()
def pattern_search(self, *arg):
"""
Search a cyclic pattern in registers and memory
Set "pattern" option for basic/extended pattern type
Usage:
MYNAME
"""
def nearby_offset(v):
for offset in range(-128, 128, 4):
pos = cyclic_pattern_offset(v + offset)
if pos is not None:
return (pos, offset)
return None
if not self._is_running():
return
reg_result = {}
regs = peda.getregs()
# search for registers with value in pattern buffer
for (r, v) in regs.items():
if len(to_hex(v)) < 8: continue
res = nearby_offset(v)
if res:
reg_result[r] = res
if reg_result:
msg("Registers contain pattern buffer:", "red")
for (r, (p, o)) in reg_result.items():
msg("%s+%d found at offset: %d" % (r.upper(), o, p))
else:
msg("No register contains pattern buffer")
# search for registers which point to pattern buffer
reg_result = {}
for (r, v) in regs.items():
if not peda.is_address(v): continue
chain = peda.examine_mem_reference(v)
(v, t, vn) = chain[-1]
if not vn: continue
o = cyclic_pattern_offset(vn.strip("'").strip('"')[:4])
if o is not None:
reg_result[r] = (len(chain), len(vn)-2, o)
if reg_result:
msg("Registers point to pattern buffer:", "yellow")
for (r, (d, l, o)) in reg_result.items():
msg("[%s] %s offset %d - size ~%d" % (r.upper(), "-->"*d, o, l))
else:
msg("No register points to pattern buffer")
# search for pattern buffer in memory
maps = peda.get_vmmap()
search_result = []
for (start, end, perm, name) in maps:
if "w" not in perm: continue # only search in writable memory
res = cyclic_pattern_search(peda.dumpmem(start, end))
for (a, l, o) in res:
a += start
search_result += [(a, l, o)]
sp = peda.getreg("sp")
if search_result:
msg("Pattern buffer found at:", "green")
for (a, l, o) in search_result:
ranges = peda.get_vmrange(a)
text = "%s : offset %4d - size %4d" % (to_address(a), o, l)
if ranges[3] == "[stack]":
text += " ($sp + %s [%d dwords])" % (to_hex(a-sp), (a-sp)//4)
else:
text += " (%s)" % ranges[3]
msg(text)
else:
msg("Pattern buffer not found in memory")
# search for references to pattern buffer in memory
ref_result = []
for (a, l, o) in search_result:
res = peda.searchmem_by_range("all", "0x%x" % a)
ref_result += [(x[0], a) for x in res]
if len(ref_result) > 0:
msg("References to pattern buffer found at:", "blue")
for (a, v) in ref_result:
ranges = peda.get_vmrange(a)
text = "%s : %s" % (to_address(a), to_address(v))
if ranges[3] == "[stack]":
text += " ($sp + %s [%d dwords])" % (to_hex(a-sp), (a-sp)//4)
else:
text += " (%s)" % ranges[3]
msg(text)
else:
msg("Reference to pattern buffer not found in memory")
return
# cyclic_pattern(), writemem()
def pattern_patch(self, *arg):
"""
Write a cyclic pattern to memory
Set "pattern" option for basic/extended pattern type
Usage:
MYNAME address size
"""
(address, size) = normalize_argv(arg, 2)
if size is None:
self._missing_argument()