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|
package sshd
import (
"context"
"fmt"
"golang.org/x/crypto/ssh"
shellCmd "gitlab.com/gitlab-org/gitlab-shell/cmd/gitlab-shell/command"
"gitlab.com/gitlab-org/gitlab-shell/internal/command/commandargs"
"gitlab.com/gitlab-org/gitlab-shell/internal/command/readwriter"
"gitlab.com/gitlab-org/gitlab-shell/internal/config"
"gitlab.com/gitlab-org/gitlab-shell/internal/sshenv"
)
type session struct {
// State set up by the connection
cfg *config.Config
channel ssh.Channel
gitlabKeyId string
remoteAddr string
// State managed by the session
execCmd string
gitProtocolVersion string
}
type execRequest struct {
Command string
}
type envRequest struct {
Name string
Value string
}
type exitStatusReq struct {
ExitStatus uint32
}
func (s *session) handle(ctx context.Context, requests <-chan *ssh.Request) {
for req := range requests {
var shouldContinue bool
switch req.Type {
case "env":
shouldContinue = s.handleEnv(req)
case "exec":
shouldContinue = s.handleExec(ctx, req)
case "shell":
shouldContinue = false
s.exit(s.handleShell(ctx, req))
default:
// Ignore unknown requests but don't terminate the session
shouldContinue = true
if req.WantReply {
req.Reply(false, []byte{})
}
}
if !shouldContinue {
s.channel.Close()
break
}
}
}
func (s *session) handleEnv(req *ssh.Request) bool {
var accepted bool
var envRequest envRequest
if err := ssh.Unmarshal(req.Payload, &envRequest); err != nil {
return false
}
switch envRequest.Name {
case sshenv.GitProtocolEnv:
s.gitProtocolVersion = envRequest.Value
accepted = true
default:
// Client requested a forbidden envvar, nothing to do
}
if req.WantReply {
req.Reply(accepted, []byte{})
}
return true
}
func (s *session) handleExec(ctx context.Context, req *ssh.Request) bool {
var execRequest execRequest
if err := ssh.Unmarshal(req.Payload, &execRequest); err != nil {
return false
}
s.execCmd = execRequest.Command
s.exit(s.handleShell(ctx, req))
return false
}
func (s *session) handleShell(ctx context.Context, req *ssh.Request) uint32 {
if req.WantReply {
req.Reply(true, []byte{})
}
args := &commandargs.Shell{
GitlabKeyId: s.gitlabKeyId,
Env: sshenv.Env{
IsSSHConnection: true,
OriginalCommand: s.execCmd,
GitProtocolVersion: s.gitProtocolVersion,
RemoteAddr: s.remoteAddr,
},
}
if err := args.ParseCommand(s.execCmd); err != nil {
s.toStderr("Failed to parse command: %v\n", err.Error())
return 128
}
rw := &readwriter.ReadWriter{
Out: s.channel,
In: s.channel,
ErrOut: s.channel.Stderr(),
}
cmd := shellCmd.Build(args, s.cfg, rw)
if cmd == nil {
s.toStderr("Unknown command: %v\n", args.CommandType)
return 128
}
if err := cmd.Execute(ctx); err != nil {
s.toStderr("remote: ERROR: %v\n", err.Error())
return 1
}
return 0
}
func (s *session) toStderr(format string, args ...interface{}) {
fmt.Fprintf(s.channel.Stderr(), format, args...)
}
func (s *session) exit(status uint32) {
req := exitStatusReq{ExitStatus: status}
s.channel.CloseWrite()
s.channel.SendRequest("exit-status", false, ssh.Marshal(req))
}
|
