mirror of
https://github.com/moul/sshportal.git
synced 2024-09-20 23:16:05 +08:00
89 lines
2 KiB
Go
89 lines
2 KiB
Go
package bastion // import "moul.io/sshportal/pkg/bastion"
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"log"
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"time"
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"github.com/gliderlabs/ssh"
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oi "github.com/reiver/go-oi"
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telnet "github.com/reiver/go-telnet"
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"moul.io/sshportal/pkg/dbmodels"
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)
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type bastionTelnetCaller struct {
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ssh ssh.Session
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}
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func (caller bastionTelnetCaller) CallTELNET(ctx telnet.Context, w telnet.Writer, r telnet.Reader) {
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go func(writer io.Writer, reader io.Reader) {
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var buffer [1]byte // Seems like the length of the buffer needs to be small, otherwise will have to wait for buffer to fill up.
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p := buffer[:]
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for {
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// Read 1 byte.
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n, err := reader.Read(p)
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if n <= 0 && err == nil {
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continue
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} else if n <= 0 && err != nil {
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break
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}
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if _, err = oi.LongWrite(writer, p); err != nil {
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log.Printf("telnet longwrite failed: %v", err)
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}
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}
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}(caller.ssh, r)
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var buffer bytes.Buffer
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var p []byte
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var crlfBuffer = [2]byte{'\r', '\n'}
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crlf := crlfBuffer[:]
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scanner := bufio.NewScanner(caller.ssh)
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scanner.Split(scannerSplitFunc)
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for scanner.Scan() {
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buffer.Write(scanner.Bytes())
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buffer.Write(crlf)
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p = buffer.Bytes()
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n, err := oi.LongWrite(w, p)
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if nil != err {
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break
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}
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if expected, actual := int64(len(p)), n; expected != actual {
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err := fmt.Errorf("transmission problem: tried sending %d bytes, but actually only sent %d bytes", expected, actual)
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fmt.Fprint(caller.ssh, err.Error())
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return
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}
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buffer.Reset()
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}
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// Wait a bit to receive data from the server (that we would send to io.Stdout).
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time.Sleep(3 * time.Millisecond)
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}
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func scannerSplitFunc(data []byte, atEOF bool) (advance int, token []byte, err error) {
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if atEOF {
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return 0, nil, nil
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}
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return bufio.ScanLines(data, atEOF)
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}
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func telnetHandler(host *dbmodels.Host) ssh.Handler {
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return func(s ssh.Session) {
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// FIXME: log session in db
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//actx := s.Context().Value(authContextKey).(*authContext)
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caller := bastionTelnetCaller{ssh: s}
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if err := telnet.DialToAndCall(host.DialAddr(), caller); err != nil {
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fmt.Fprintf(s, "error: %v", err)
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}
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}
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}
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