68 lines
1.5 KiB
Go
68 lines
1.5 KiB
Go
package sshd
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import (
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"net"
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"github.com/shazow/rateio"
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"golang.org/x/crypto/ssh"
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)
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// Container for the connection and ssh-related configuration
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type SSHListener struct {
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net.Listener
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config *ssh.ServerConfig
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RateLimit func() rateio.Limiter
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HandlerFunc func(term *Terminal)
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}
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// Make an SSH listener socket
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func ListenSSH(laddr string, config *ssh.ServerConfig) (*SSHListener, error) {
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socket, err := net.Listen("tcp", laddr)
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if err != nil {
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return nil, err
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}
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l := SSHListener{Listener: socket, config: config}
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return &l, nil
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}
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func (l *SSHListener) handleConn(conn net.Conn) (*Terminal, error) {
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if l.RateLimit != nil {
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// TODO: Configurable Limiter?
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conn = ReadLimitConn(conn, l.RateLimit())
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}
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// Upgrade TCP connection to SSH connection
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sshConn, channels, requests, err := ssh.NewServerConn(conn, l.config)
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if err != nil {
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return nil, err
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}
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// FIXME: Disconnect if too many faulty requests? (Avoid DoS.)
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go ssh.DiscardRequests(requests)
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return NewSession(sshConn, channels)
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}
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// Accept incoming connections as terminal requests and yield them
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func (l *SSHListener) Serve() {
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defer l.Close()
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for {
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conn, err := l.Accept()
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if err != nil {
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logger.Printf("Failed to accept connection: %s", err)
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break
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}
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// Goroutineify to resume accepting sockets early
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go func() {
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term, err := l.handleConn(conn)
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if err != nil {
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logger.Printf("[%s] Failed to handshake: %s", conn.RemoteAddr(), err)
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return
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}
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l.HandlerFunc(term)
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}()
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}
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}
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