17657: Allow ssh port forwarding to container ports.
authorTom Clegg <tom@curii.com>
Sun, 9 May 2021 00:04:15 +0000 (20:04 -0400)
committerTom Clegg <tom@curii.com>
Mon, 10 May 2021 14:24:44 +0000 (10:24 -0400)
Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>

lib/controller/localdb/container_gateway_test.go
lib/crunchrun/container_gateway.go
lib/crunchrun/crunchrun.go

index aff569b0988d177b1be42eca9fdffc33a40d55d0..2a77357677b3d7f064832d471257866ef356b07a 100644 (file)
@@ -10,6 +10,8 @@ import (
        "crypto/sha256"
        "fmt"
        "io"
+       "io/ioutil"
+       "net"
        "time"
 
        "git.arvados.org/arvados.git/lib/config"
@@ -18,6 +20,7 @@ import (
        "git.arvados.org/arvados.git/sdk/go/arvadostest"
        "git.arvados.org/arvados.git/sdk/go/auth"
        "git.arvados.org/arvados.git/sdk/go/ctxlog"
+       "golang.org/x/crypto/ssh"
        check "gopkg.in/check.v1"
 )
 
@@ -53,11 +56,12 @@ func (s *ContainerGatewaySuite) SetUpSuite(c *check.C) {
        authKey := fmt.Sprintf("%x", h.Sum(nil))
 
        s.gw = &crunchrun.Gateway{
-               DockerContainerID: new(string),
-               ContainerUUID:     s.ctrUUID,
-               AuthSecret:        authKey,
-               Address:           "localhost:0",
-               Log:               ctxlog.TestLogger(c),
+               DockerContainerID:  new(string),
+               ContainerUUID:      s.ctrUUID,
+               AuthSecret:         authKey,
+               Address:            "localhost:0",
+               Log:                ctxlog.TestLogger(c),
+               ContainerIPAddress: func() (string, error) { return "localhost", nil },
        }
        c.Assert(s.gw.Start(), check.IsNil)
        rootctx := auth.NewContext(context.Background(), &auth.Credentials{Tokens: []string{s.cluster.SystemRootToken}})
@@ -120,6 +124,68 @@ func (s *ContainerGatewaySuite) TestConfig(c *check.C) {
        }
 }
 
+func (s *ContainerGatewaySuite) TestDirectTCP(c *check.C) {
+       // Set up servers on a few TCP ports
+       var addrs []string
+       for i := 0; i < 3; i++ {
+               ln, err := net.Listen("tcp", ":0")
+               c.Assert(err, check.IsNil)
+               defer ln.Close()
+               addrs = append(addrs, ln.Addr().String())
+               go func() {
+                       for {
+                               conn, err := ln.Accept()
+                               if err != nil {
+                                       return
+                               }
+                               var gotAddr string
+                               fmt.Fscanf(conn, "%s\n", &gotAddr)
+                               c.Logf("stub server listening at %s received string %q from remote %s", ln.Addr().String(), gotAddr, conn.RemoteAddr())
+                               if gotAddr == ln.Addr().String() {
+                                       fmt.Fprintf(conn, "%s\n", ln.Addr().String())
+                               }
+                               conn.Close()
+                       }
+               }()
+       }
+
+       c.Logf("connecting to %s", s.gw.Address)
+       sshconn, err := s.localdb.ContainerSSH(s.ctx, arvados.ContainerSSHOptions{UUID: s.ctrUUID})
+       c.Assert(err, check.IsNil)
+       c.Assert(sshconn.Conn, check.NotNil)
+       defer sshconn.Conn.Close()
+       conn, chans, reqs, err := ssh.NewClientConn(sshconn.Conn, "zzzz-dz642-abcdeabcdeabcde", &ssh.ClientConfig{
+               HostKeyCallback: func(hostname string, remote net.Addr, key ssh.PublicKey) error { return nil },
+       })
+       c.Assert(err, check.IsNil)
+       client := ssh.NewClient(conn, chans, reqs)
+       for _, expectAddr := range addrs {
+               _, port, err := net.SplitHostPort(expectAddr)
+               c.Assert(err, check.IsNil)
+
+               c.Logf("trying foo:%s", port)
+               {
+                       conn, err := client.Dial("tcp", "foo:"+port)
+                       c.Assert(err, check.IsNil)
+                       conn.SetDeadline(time.Now().Add(time.Second))
+                       buf, err := ioutil.ReadAll(conn)
+                       c.Check(err, check.IsNil)
+                       c.Check(string(buf), check.Equals, "")
+               }
+
+               c.Logf("trying localhost:%s", port)
+               {
+                       conn, err := client.Dial("tcp", "localhost:"+port)
+                       c.Assert(err, check.IsNil)
+                       conn.SetDeadline(time.Now().Add(time.Second))
+                       conn.Write([]byte(expectAddr + "\n"))
+                       var gotAddr string
+                       fmt.Fscanf(conn, "%s\n", &gotAddr)
+                       c.Check(gotAddr, check.Equals, expectAddr)
+               }
+       }
+}
+
 func (s *ContainerGatewaySuite) TestConnect(c *check.C) {
        c.Logf("connecting to %s", s.gw.Address)
        sshconn, err := s.localdb.ContainerSSH(s.ctx, arvados.ContainerSSHOptions{UUID: s.ctrUUID})
index 1a87b8c4f71d1db95b62dc6c572107f9e1e815d8..2ec24bac788f5a301a823621724eff82438a5fd7 100644 (file)
@@ -17,13 +17,18 @@ import (
        "os"
        "os/exec"
        "sync"
+       "sync/atomic"
        "syscall"
+       "time"
 
        "git.arvados.org/arvados.git/lib/selfsigned"
+       "git.arvados.org/arvados.git/sdk/go/ctxlog"
        "git.arvados.org/arvados.git/sdk/go/httpserver"
        "github.com/creack/pty"
+       dockerclient "github.com/docker/docker/client"
        "github.com/google/shlex"
        "golang.org/x/crypto/ssh"
+       "golang.org/x/net/context"
 )
 
 type Gateway struct {
@@ -34,6 +39,8 @@ type Gateway struct {
        Log               interface {
                Printf(fmt string, args ...interface{})
        }
+       // return local ip address of running container, or "" if not available
+       ContainerIPAddress func() (string, error)
 
        sshConfig   ssh.ServerConfig
        requestAuth string
@@ -194,140 +201,228 @@ func (gw *Gateway) handleSSH(w http.ResponseWriter, req *http.Request) {
        defer conn.Close()
        go ssh.DiscardRequests(reqs)
        for newch := range newchans {
-               if newch.ChannelType() != "session" {
-                       newch.Reject(ssh.UnknownChannelType, fmt.Sprintf("unsupported channel type %q", newch.ChannelType()))
-                       continue
+               switch newch.ChannelType() {
+               case "direct-tcpip":
+                       go gw.handleDirectTCPIP(ctx, newch)
+               case "session":
+                       go gw.handleSession(ctx, newch, detachKeys, username)
+               default:
+                       go newch.Reject(ssh.UnknownChannelType, fmt.Sprintf("unsupported channel type %q", newch.ChannelType()))
                }
-               ch, reqs, err := newch.Accept()
+       }
+}
+
+func (gw *Gateway) handleDirectTCPIP(ctx context.Context, newch ssh.NewChannel) {
+       ch, reqs, err := newch.Accept()
+       if err != nil {
+               gw.Log.Printf("accept direct-tcpip channel: %s", err)
+               return
+       }
+       defer ch.Close()
+       go ssh.DiscardRequests(reqs)
+
+       // RFC 4254 7.2 (copy of channelOpenDirectMsg in
+       // golang.org/x/crypto/ssh)
+       var msg struct {
+               Raddr string
+               Rport uint32
+               Laddr string
+               Lport uint32
+       }
+       err = ssh.Unmarshal(newch.ExtraData(), &msg)
+       if err != nil {
+               fmt.Fprintf(ch.Stderr(), "unmarshal direct-tcpip extradata: %s\n", err)
+               return
+       }
+       switch msg.Raddr {
+       case "localhost", "0.0.0.0", "127.0.0.1", "::1", "::":
+       default:
+               fmt.Fprintf(ch.Stderr(), "cannot forward to ports on %q, only localhost\n", msg.Raddr)
+               return
+       }
+
+       var dstaddr string
+       if gw.ContainerIPAddress != nil {
+               dstaddr, err = gw.ContainerIPAddress()
                if err != nil {
-                       gw.Log.Printf("accept channel: %s", err)
+                       fmt.Fprintf(ch.Stderr(), "container has no IP address: %s\n", err)
                        return
                }
-               var pty0, tty0 *os.File
-               go func() {
-                       // Where to send errors/messages for the
-                       // client to see
-                       logw := io.Writer(ch.Stderr())
-                       // How to end lines when sending
-                       // errors/messages to the client (changes to
-                       // \r\n when using a pty)
-                       eol := "\n"
-                       // Env vars to add to child process
-                       termEnv := []string(nil)
-                       for req := range reqs {
-                               ok := false
-                               switch req.Type {
-                               case "shell", "exec":
-                                       ok = true
-                                       var payload struct {
-                                               Command string
-                                       }
-                                       ssh.Unmarshal(req.Payload, &payload)
-                                       execargs, err := shlex.Split(payload.Command)
-                                       if err != nil {
-                                               fmt.Fprintf(logw, "error parsing supplied command: %s"+eol, err)
-                                               return
-                                       }
-                                       if len(execargs) == 0 {
-                                               execargs = []string{"/bin/bash", "-login"}
-                                       }
-                                       go func() {
-                                               cmd := exec.CommandContext(ctx, "docker", "exec", "-i", "--detach-keys="+detachKeys, "--user="+username)
-                                               cmd.Stdin = ch
-                                               cmd.Stdout = ch
-                                               cmd.Stderr = ch.Stderr()
-                                               if tty0 != nil {
-                                                       cmd.Args = append(cmd.Args, "-t")
-                                                       cmd.Stdin = tty0
-                                                       cmd.Stdout = tty0
-                                                       cmd.Stderr = tty0
-                                                       var wg sync.WaitGroup
-                                                       defer wg.Wait()
-                                                       wg.Add(2)
-                                                       go func() { io.Copy(ch, pty0); wg.Done() }()
-                                                       go func() { io.Copy(pty0, ch); wg.Done() }()
-                                                       // Send our own debug messages to tty as well.
-                                                       logw = tty0
-                                               }
-                                               cmd.Args = append(cmd.Args, *gw.DockerContainerID)
-                                               cmd.Args = append(cmd.Args, execargs...)
-                                               cmd.SysProcAttr = &syscall.SysProcAttr{
-                                                       Setctty: tty0 != nil,
-                                                       Setsid:  true,
-                                               }
-                                               cmd.Env = append(os.Environ(), termEnv...)
-                                               err := cmd.Run()
-                                               var resp struct {
-                                                       Status uint32
-                                               }
-                                               if exiterr, ok := err.(*exec.ExitError); ok {
-                                                       if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
-                                                               resp.Status = uint32(status.ExitStatus())
-                                                       }
-                                               } else if err != nil {
-                                                       // Propagate errors like `exec: "docker": executable file not found in $PATH`
-                                                       fmt.Fprintln(ch.Stderr(), err)
-                                               }
-                                               errClose := ch.CloseWrite()
-                                               if resp.Status == 0 && (err != nil || errClose != nil) {
-                                                       resp.Status = 1
-                                               }
-                                               ch.SendRequest("exit-status", false, ssh.Marshal(&resp))
-                                               ch.Close()
-                                       }()
-                               case "pty-req":
-                                       eol = "\r\n"
-                                       p, t, err := pty.Open()
-                                       if err != nil {
-                                               fmt.Fprintf(ch.Stderr(), "pty failed: %s"+eol, err)
-                                               break
-                                       }
-                                       defer p.Close()
-                                       defer t.Close()
-                                       pty0, tty0 = p, t
-                                       ok = true
-                                       var payload struct {
-                                               Term string
-                                               Cols uint32
-                                               Rows uint32
-                                               X    uint32
-                                               Y    uint32
-                                       }
-                                       ssh.Unmarshal(req.Payload, &payload)
-                                       termEnv = []string{"TERM=" + payload.Term, "USE_TTY=1"}
-                                       err = pty.Setsize(pty0, &pty.Winsize{Rows: uint16(payload.Rows), Cols: uint16(payload.Cols), X: uint16(payload.X), Y: uint16(payload.Y)})
-                                       if err != nil {
-                                               fmt.Fprintf(logw, "pty-req: setsize failed: %s"+eol, err)
-                                       }
-                               case "window-change":
-                                       var payload struct {
-                                               Cols uint32
-                                               Rows uint32
-                                               X    uint32
-                                               Y    uint32
-                                       }
-                                       ssh.Unmarshal(req.Payload, &payload)
-                                       err := pty.Setsize(pty0, &pty.Winsize{Rows: uint16(payload.Rows), Cols: uint16(payload.Cols), X: uint16(payload.X), Y: uint16(payload.Y)})
-                                       if err != nil {
-                                               fmt.Fprintf(logw, "window-change: setsize failed: %s"+eol, err)
-                                               break
+       }
+       if dstaddr == "" {
+               fmt.Fprintf(ch.Stderr(), "container has no IP address\n")
+               return
+       }
+
+       dst := net.JoinHostPort(dstaddr, fmt.Sprintf("%d", msg.Rport))
+       tcpconn, err := net.Dial("tcp", dst)
+       if err != nil {
+               fmt.Fprintf(ch.Stderr(), "%s: %s\n", dst, err)
+               return
+       }
+       go func() {
+               n, _ := io.Copy(ch, tcpconn)
+               ctxlog.FromContext(ctx).Debugf("tcpip: sent %d bytes\n", n)
+               ch.CloseWrite()
+       }()
+       n, _ := io.Copy(tcpconn, ch)
+       ctxlog.FromContext(ctx).Debugf("tcpip: received %d bytes\n", n)
+}
+
+func (gw *Gateway) handleSession(ctx context.Context, newch ssh.NewChannel, detachKeys, username string) {
+       ch, reqs, err := newch.Accept()
+       if err != nil {
+               gw.Log.Printf("accept session channel: %s", err)
+               return
+       }
+       var pty0, tty0 *os.File
+       // Where to send errors/messages for the client to see
+       logw := io.Writer(ch.Stderr())
+       // How to end lines when sending errors/messages to the client
+       // (changes to \r\n when using a pty)
+       eol := "\n"
+       // Env vars to add to child process
+       termEnv := []string(nil)
+       for req := range reqs {
+               ok := false
+               switch req.Type {
+               case "shell", "exec":
+                       ok = true
+                       var payload struct {
+                               Command string
+                       }
+                       ssh.Unmarshal(req.Payload, &payload)
+                       execargs, err := shlex.Split(payload.Command)
+                       if err != nil {
+                               fmt.Fprintf(logw, "error parsing supplied command: %s"+eol, err)
+                               return
+                       }
+                       if len(execargs) == 0 {
+                               execargs = []string{"/bin/bash", "-login"}
+                       }
+                       go func() {
+                               cmd := exec.CommandContext(ctx, "docker", "exec", "-i", "--detach-keys="+detachKeys, "--user="+username)
+                               cmd.Stdin = ch
+                               cmd.Stdout = ch
+                               cmd.Stderr = ch.Stderr()
+                               if tty0 != nil {
+                                       cmd.Args = append(cmd.Args, "-t")
+                                       cmd.Stdin = tty0
+                                       cmd.Stdout = tty0
+                                       cmd.Stderr = tty0
+                                       var wg sync.WaitGroup
+                                       defer wg.Wait()
+                                       wg.Add(2)
+                                       go func() { io.Copy(ch, pty0); wg.Done() }()
+                                       go func() { io.Copy(pty0, ch); wg.Done() }()
+                                       // Send our own debug messages to tty as well.
+                                       logw = tty0
+                               }
+                               cmd.Args = append(cmd.Args, *gw.DockerContainerID)
+                               cmd.Args = append(cmd.Args, execargs...)
+                               cmd.SysProcAttr = &syscall.SysProcAttr{
+                                       Setctty: tty0 != nil,
+                                       Setsid:  true,
+                               }
+                               cmd.Env = append(os.Environ(), termEnv...)
+                               err := cmd.Run()
+                               var resp struct {
+                                       Status uint32
+                               }
+                               if exiterr, ok := err.(*exec.ExitError); ok {
+                                       if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+                                               resp.Status = uint32(status.ExitStatus())
                                        }
-                                       ok = true
-                               case "env":
-                                       // TODO: implement "env"
-                                       // requests by setting env
-                                       // vars in the docker-exec
-                                       // command (not docker-exec's
-                                       // own environment, which
-                                       // would be a gaping security
-                                       // hole).
-                               default:
-                                       // fmt.Fprintf(logw, "declining %q req"+eol, req.Type)
+                               } else if err != nil {
+                                       // Propagate errors like `exec: "docker": executable file not found in $PATH`
+                                       fmt.Fprintln(ch.Stderr(), err)
                                }
-                               if req.WantReply {
-                                       req.Reply(ok, nil)
+                               errClose := ch.CloseWrite()
+                               if resp.Status == 0 && (err != nil || errClose != nil) {
+                                       resp.Status = 1
                                }
+                               ch.SendRequest("exit-status", false, ssh.Marshal(&resp))
+                               ch.Close()
+                       }()
+               case "pty-req":
+                       eol = "\r\n"
+                       p, t, err := pty.Open()
+                       if err != nil {
+                               fmt.Fprintf(ch.Stderr(), "pty failed: %s"+eol, err)
+                               break
+                       }
+                       defer p.Close()
+                       defer t.Close()
+                       pty0, tty0 = p, t
+                       ok = true
+                       var payload struct {
+                               Term string
+                               Cols uint32
+                               Rows uint32
+                               X    uint32
+                               Y    uint32
+                       }
+                       ssh.Unmarshal(req.Payload, &payload)
+                       termEnv = []string{"TERM=" + payload.Term, "USE_TTY=1"}
+                       err = pty.Setsize(pty0, &pty.Winsize{Rows: uint16(payload.Rows), Cols: uint16(payload.Cols), X: uint16(payload.X), Y: uint16(payload.Y)})
+                       if err != nil {
+                               fmt.Fprintf(logw, "pty-req: setsize failed: %s"+eol, err)
                        }
-               }()
+               case "window-change":
+                       var payload struct {
+                               Cols uint32
+                               Rows uint32
+                               X    uint32
+                               Y    uint32
+                       }
+                       ssh.Unmarshal(req.Payload, &payload)
+                       err := pty.Setsize(pty0, &pty.Winsize{Rows: uint16(payload.Rows), Cols: uint16(payload.Cols), X: uint16(payload.X), Y: uint16(payload.Y)})
+                       if err != nil {
+                               fmt.Fprintf(logw, "window-change: setsize failed: %s"+eol, err)
+                               break
+                       }
+                       ok = true
+               case "env":
+                       // TODO: implement "env"
+                       // requests by setting env
+                       // vars in the docker-exec
+                       // command (not docker-exec's
+                       // own environment, which
+                       // would be a gaping security
+                       // hole).
+               default:
+                       // fmt.Fprintf(logw, "declining %q req"+eol, req.Type)
+               }
+               if req.WantReply {
+                       req.Reply(ok, nil)
+               }
+       }
+}
+
+func dockerContainerIPAddress(containerID *string) func() (string, error) {
+       var saved atomic.Value
+       return func() (string, error) {
+               if ip, ok := saved.Load().(*string); ok {
+                       return *ip, nil
+               }
+               docker, err := dockerclient.NewClient(dockerclient.DefaultDockerHost, "1.21", nil, nil)
+               if err != nil {
+                       return "", fmt.Errorf("cannot create docker client: %s", err)
+               }
+               ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(time.Minute))
+               defer cancel()
+               ctr, err := docker.ContainerInspect(ctx, *containerID)
+               if err != nil {
+                       return "", fmt.Errorf("cannot get docker container info: %s", err)
+               }
+               ip := ctr.NetworkSettings.IPAddress
+               if ip == "" {
+                       // TODO: try to enable networking if it wasn't
+                       // already enabled when the container was
+                       // created.
+                       return "", fmt.Errorf("container has no IP address")
+               }
+               saved.Store(&ip)
+               return ip, nil
        }
 }
index 969682f465cefe56a0430b80bef2a461d7022436..88c137277cfde57ccdab722212e9c3bf2d4ba310 100644 (file)
@@ -1880,11 +1880,12 @@ func (command) RunCommand(prog string, args []string, stdin io.Reader, stdout, s
        }
 
        cr.gateway = Gateway{
-               Address:           os.Getenv("GatewayAddress"),
-               AuthSecret:        os.Getenv("GatewayAuthSecret"),
-               ContainerUUID:     containerID,
-               DockerContainerID: &cr.ContainerID,
-               Log:               cr.CrunchLog,
+               Address:            os.Getenv("GatewayAddress"),
+               AuthSecret:         os.Getenv("GatewayAuthSecret"),
+               ContainerUUID:      containerID,
+               DockerContainerID:  &cr.ContainerID,
+               Log:                cr.CrunchLog,
+               ContainerIPAddress: dockerContainerIPAddress(&cr.ContainerID),
        }
        os.Unsetenv("GatewayAuthSecret")
        if cr.gateway.Address != "" {