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How does scanning for a double value work?

 
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Michaelc
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Joined: 15 May 2016
Posts: 47

PostPosted: Sat Oct 14, 2017 6:02 pm    Post subject: How does scanning for a double value work? Reply with quote

Here is my question about the memory:

So I have a base address of a chunk of memory from it's size, from VirtualQueryEx

start = mbi.BaseAddress
finish = mbi.RegionSize

So at this time, I use while and this is how it looks like

while index < finish:
# access the memory here:
while memory function( index)
# then index += 1, for the inner loop

## this line complete the outer while loop
index += mbi.RegionSize


so Why did I put down index += 1 ?

That's because what I think about the memory looks like this
(short)(int)(double)(int)(int)(int)(double) and so on,

since I can't predict which address is the beginning of a double, the only way
to deal with that is to use increment by 1.

Now, from what I have been reading, it seems there is a better way to do it,
for instance, a for loop.

for(start,finish, 8)

why 8? because double begins at exact 0 or multiple of 8 bytes, right?






[code]

import ctypes
from ctypes.wintypes import WORD, DWORD, LPVOID

PVOID = LPVOID
SIZE_T = ctypes.c_size_t

# https://msdn.microsoft.com/en-us/library/aa383751#DWORD_PTR
if ctypes.sizeof(ctypes.c_void_p) == ctypes.sizeof(ctypes.c_ulonglong):
DWORD_PTR = ctypes.c_ulonglong
elif ctypes.sizeof(ctypes.c_void_p) == ctypes.sizeof(ctypes.c_ulong):
DWORD_PTR = ctypes.c_ulong

class SYSTEM_INFO(ctypes.Structure):
"""https://msdn.microsoft.com/en-us/library/ms724958"""
class _U(ctypes.Union):
class _S(ctypes.Structure):
_fields_ = (('wProcessorArchitecture', WORD),
('wReserved', WORD))
_fields_ = (('dwOemId', DWORD), # obsolete
('_s', _S))
_anonymous_ = ('_s',)
_fields_ = (('_u', _U),
('dwPageSize', DWORD),
('lpMinimumApplicationAddress', LPVOID),
('lpMaximumApplicationAddress', LPVOID),
('dwActiveProcessorMask', DWORD_PTR),
('dwNumberOfProcessors', DWORD),
('dwProcessorType', DWORD),
('dwAllocationGranularity', DWORD),
('wProcessorLevel', WORD),
('wProcessorRevision', WORD))
_anonymous_ = ('_u',)

LPSYSTEM_INFO = ctypes.POINTER(SYSTEM_INFO)



Kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)
Kernel32.GetSystemInfo.restype = None
Kernel32.GetSystemInfo.argtypes = (LPSYSTEM_INFO,)

sysinfo = SYSTEM_INFO()
Kernel32.GetSystemInfo(ctypes.byref(sysinfo))

print(sysinfo.lpMinimumApplicationAddress)
print(sysinfo.lpMaximumApplicationAddress)


# maybe it will change, maybe it won't. Assuming it won't.

# 2nd, get Open process.
import psutil
import sys

for proc in psutil.process_iter():
if str('swtor.exe') in str(proc.name) and \
proc.memory_info().rss > 1000000000:
PID = proc.pid
print('PID:',PID)


PROCESS_QUERY_INFORMATION = 0x0400
PROCESS_VM_READ = 0x0010

Process = Kernel32.OpenProcess(PROCESS_QUERY_INFORMATION|PROCESS_VM_READ, False, PID)
print('process:', Process)



# 3rd

class MEMORY_BASIC_INFORMATION(ctypes.Structure):
"""https://msdn.microsoft.com/en-us/library/aa366775"""
_fields_ = (('BaseAddress', PVOID),
('AllocationBase', PVOID),
('AllocationProtect', DWORD),
('RegionSize', SIZE_T),
('State', DWORD),
('Protect', DWORD),
('Type', DWORD))

##PMEMORY_BASIC_INFORMATION = ctypes.POINTER(MEMORY_BASIC_INFORMATION)

mbi = MEMORY_BASIC_INFORMATION()
##sysinfo.lpMinimumApplicationAddress

print('VirtualQueryEx ran properly?',Kernel32.VirtualQueryEx(Process, \
sysinfo.lpMinimumApplicationAddress, ctypes.byref(mbi),ctypes.sizeof(mbi)))
# sysinfo.lpMinimumApplicationAddress replaced by None

##print('')
##print('mbi start')
##print('mbi.BaseAddress: ',mbi.BaseAddress)
##print('mbi.AllocationBase: ',mbi.AllocationBase)
##print('mbi.AllocationProtect: ',mbi.AllocationProtect)
##print('mbi.RegionSize: ',mbi.RegionSize)
##print('mbi.State: ',mbi.State)
##print('mbi.Protect: ', mbi.Protect)
##print('mbi.Type: ',mbi.Type)



ReadProcessMemory = Kernel32.ReadProcessMemory

##
MEM_COMMIT = 0x00001000;
PAGE_READWRITE = 0x04;

##buffer = ctypes.c_uint()
buffer = ctypes.c_double()

nread = SIZE_T()

##start = ctypes.c_void_p(mbi.BaseAddress)

current_address = sysinfo.lpMinimumApplicationAddress
end_address = sysinfo.lpMaximumApplicationAddress

hit_count = 0
target_value = -159

hit_pool = list()


while current_address < end_address:
Kernel32.VirtualQueryEx(Process, \
current_address, ctypes.byref(mbi),ctypes.sizeof(mbi))

if mbi.Protect == PAGE_READWRITE and mbi.State == MEM_COMMIT :
print('This region can be scanned!')
index = current_address
end = current_address + mbi.RegionSize - 7

for i in range(index, end, 8):
if ReadProcessMemory(Process, i, ctypes.byref(buffer), \
ctypes.sizeof(buffer), ctypes.byref(nread)):
## pass
# impletment value comparison now.
if buffer.value < (target_value + 1) and \
buffer.value > (target_value - 1):
print(buffer.value, hex(i), 'hit:', hit_count)
hit_count += 1
hit_pool.append(hex(i))


else:
print('else happend.')
## pass
## raise ctypes.WinError(ctypes.get_last_error())

current_address += mbi.RegionSize



print('done.')
print(hit_count)

print(hit_pool)
[/code]
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