kashimastro / simplenetwork Goto Github PK

simple TCP server / client C++ linux socket

License: MIT License

Makefile 3.74% C++ 94.17% PHP 2.09%

tcp socket linux networks simple library little-library c-plus-plus multithreading server client

simplenetwork's Introduction

SimpleNetwork


$ ./server 5050 1 

$ ./client 127.0.0.1 5050 message

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simplenetwork's Issues

configuration steps

need steps to be followed to configure this project

License question

Hello,
Maybe I'm missing it, but what is the license for the code you've posted?
Regards,

I think you use 'setsockopt' error

if( (setsockopt(sockfd, SOL_SOCKET, opts.size(), (char *)&opt, sizeof(opt))) < 0 ) {
cerr << "Errore setsockopt" << endl;
return -1;
}
-------------------->>>>>
if( (setsockopt(sockfd, SOL_SOCKET, opts.at(i), (char *)&opt, sizeof(opt))) < 0 ) {
cerr << "Errore setsockopt" << endl;
return -1;
}

Server doesn't respond to multiple clients

Even though server seems to be made with multiple connections in mind it wont respond to multiple clients as it will overwrite newsockfd on every new connection, I'm sorry if that's how it was meant to be.

Computer freeze

SimpleNetwork/example-server/server.cpp

Line 9 in 3c20185

while(1)

If remove while in loop my computer changed state to freeze and help only reboot

Global Buffer Overflow in Commit 29bc615f0d9910eb2f59aa8dff1f54f0e3af4496

Hi!

I was running my fuzzer in the background again when I discovered a global buffer overflow bug in the SimpleNetwork TCPServer.

Compiling the project

$ cd src
$ make
$ cd ../example-server
$ make

Global Buffer Overflow

Server commit 29bc615 suffers from a global buffer overflow when the TCPServer receives a single large packet containing ASCII characters. Using the following python3 script will invoke a global buffer overflow:

import socket

host = "localhost"
port = 1234                   
buf = b'A'*50000

try:
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((host, port))
    s.sendall(buf)
    data = s.recv(1024)
    s.close()
    print('Received', repr(data))
except:
    print("Finished...")

Compiling the project with address sanitizer helps confirm this issue. Here is the makefile for the example TCPServer:

all: 
        g++ -Wall -o server server.cpp -I../src/ ../src/TCPServer.cpp ../src/TCPClient.cpp -std=c++11 -lpthread -fsanitize=address

Address Sanitizer Output:

=================================================================
==15095==ERROR: AddressSanitizer: global-buffer-overflow on address 0xaaaae7e8f5c0 at pc 0xaaaae7e5b684 bp 0xffffa1efe720 sp 0xffffa1efe738
WRITE of size 1 at 0xaaaae7e8f5c0 thread T2
    #0 0xaaaae7e5b680 in TCPServer::Task(void*) (/home/kali/projects/SimpleNetwork/example-server/server+0xb680)
    #1 0xffffa595edd4 in start_thread nptl/pthread_create.c:442
    #2 0xffffa59c7e58 in thread_start ../sysdeps/unix/sysv/linux/aarch64/clone.S:79

0xaaaae7e8f5c0 is located 0 bytes to the right of global variable 'msg' defined in '../src/TCPServer.cpp:3:6' (0xaaaae7e855c0) of size 40960
0xaaaae7e8f5c0 is located 32 bytes to the left of global variable 'num_client' defined in '../src/TCPServer.cpp:4:5' (0xaaaae7e8f5e0) of size 4
SUMMARY: AddressSanitizer: global-buffer-overflow (/home/kali/projects/SimpleNetwork/example-server/server+0xb680) in TCPServer::Task(void*)
Shadow bytes around the buggy address:
  0x15655cfd1e60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x15655cfd1e70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x15655cfd1e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x15655cfd1e90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x15655cfd1ea0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x15655cfd1eb0: 00 00 00 00 00 00 00 00[f9]f9 f9 f9 04 f9 f9 f9
  0x15655cfd1ec0: f9 f9 f9 f9 04 f9 f9 f9 f9 f9 f9 f9 01 f9 f9 f9
  0x15655cfd1ed0: f9 f9 f9 f9 00 00 00 f9 f9 f9 f9 f9 00 00 00 f9
  0x15655cfd1ee0: f9 f9 f9 f9 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9
  0x15655cfd1ef0: 00 00 00 00 01 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
  0x15655cfd1f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
Thread T2 created by T0 here:
    #0 0xffffa5dda234 in __interceptor_pthread_create ../../../../src/libsanitizer/asan/asan_interceptors.cpp:207
    #1 0xaaaae7e5c360 in TCPServer::accepted() (/home/kali/projects/SimpleNetwork/example-server/server+0xc360)
    #2 0xaaaae7e566bc in main (/home/kali/projects/SimpleNetwork/example-server/server+0x66bc)
    #3 0xffffa590777c in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #4 0xffffa5907854 in __libc_start_main_impl ../csu/libc-start.c:381
    #5 0xaaaae7e543ec in _start (/home/kali/projects/SimpleNetwork/example-server/server+0x43ec)

==15095==ABORTING

What is enable_message_runtime's meaning?

I'm a beginner of cpp and linux, and I'm wondering about this.

Memory access violation in TcpClient

You have a memory access violation on line 69. Should be buffer[size - 1] = '\0'; to fix the off-by-one.

Double Free in TCPServer

Hi there!

I was running my fuzzer in the background when I discovered a double free in the SimpleNetwork TCPServer.

Impact

Triggering the double free will allow client to crash any SimpleNetwork TCP server remotely. In other situations, double free vulnerabilities can cause undefined behavior and potentially code execution in the right circumstances.

Reproduction

Create a file with a large amount of random characters

Start a TCP server and send the large file to the server a few consecutive times

View the crash and gdb backtrace

Extra Resources

server will crash when a new client connects after one client disconnected

The reasion is no cleaning to Message member in the Task function. Since Message is a duplicate of newsockfd, remove the Message member will solve the problem

compile error

Hi, kashimAstro

please check your update for solve the Issue #10

g++ -Wall -o server server.cpp -I../src/ ../src/TCPServer.cpp ../src/TCPClient.cpp -std=c++11 -lpthread
server.cpp: In function ‘void* received(void*)’:
server.cpp:53:13: error: could not convert ‘desc’ from ‘std::vector<descript_socket*>’ to ‘bool’
if( desc )
^
Makefile:2: recipe for target 'all' failed
make: *** [all] Error 1

Thanks
@kashimAstro

No Licence-File

Please consider adding a license, otherwise no one is allowed to use your code. Choose a License. I would recommend to use MIT-License.

pthread_create

void TCPServer::accepted()
{
socklen_t sosize = sizeof(clientAddress);
descript_socket so = new descript_socket;
so->socket = accept(sockfd,(struct sockaddr)&clientAddress,&sosize);
so->id = num_client;
so->ip = inet_ntoa(clientAddress.sin_addr);
newsockfd.push_back( so );
cerr << "accept client[ id:" << newsockfd[num_client]->id <<
" ip:" << newsockfd[num_client]->ip <<
" handle:" << newsockfd[num_client]->socket << " ]" << endl;

//pthread_create(&serverThread[num_client], NULL, &Task, (void *)newsockfd[num_client]);
pthread_create(&serverThread[num_client], NULL, Task, (void *)newsockfd[num_client]);

isonline=true;
num_client++;

}

why use "&Task" ? I think should use “Task” !! both ways of writing code can work, I can't understand the reason of them.

@kashimAstro

compile errors

[root@jeff:/usr/src/SimpleNetwork/example-server] # make
g++ -Wall -o server server.cpp -I../src/ ../src/TCPServer.cpp ../src/TCPClient.cpp -std=c++11 -lpthread
server.cpp: In function ‘void* loop(void*)’:
server.cpp:24:1: warning: no return statement in function returning non-void [-Wreturn-type]
../src/TCPServer.cpp: In member function ‘std::string TCPServer::receive()’:
../src/TCPServer.cpp:45:51: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
../src/TCPClient.cpp: In member function ‘bool TCPClient::setup(std::string, int)’:
../src/TCPClient.cpp:20:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
[root@jeff:/usr/src/SimpleNetwork] # g++ --version
g++ (GCC) 4.7.2 20121015 (Red Hat 4.7.2-5)
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.