package crunchrun
import (
+ "crypto/hmac"
"crypto/rand"
"crypto/rsa"
+ "crypto/sha256"
+ "crypto/tls"
"fmt"
"io"
"net"
"sync"
"syscall"
+ "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"
"github.com/google/shlex"
"golang.org/x/crypto/ssh"
+ "golang.org/x/net/context"
)
-// startGatewayServer starts an http server that allows authenticated
-// clients to open an interactive "docker exec" session and (in
-// future) connect to tcp ports inside the docker container.
-func (runner *ContainerRunner) startGatewayServer() error {
- runner.gatewaySSHConfig = &ssh.ServerConfig{
+type GatewayTarget interface {
+ // Command that will execute cmd inside the container
+ InjectCommand(ctx context.Context, detachKeys, username string, usingTTY bool, cmd []string) (*exec.Cmd, error)
+
+ // IP address inside container
+ IPAddress() (string, error)
+}
+
+type GatewayTargetStub struct{}
+
+func (GatewayTargetStub) IPAddress() (string, error) { return "127.0.0.1", nil }
+func (GatewayTargetStub) InjectCommand(ctx context.Context, detachKeys, username string, usingTTY bool, cmd []string) (*exec.Cmd, error) {
+ return exec.CommandContext(ctx, cmd[0], cmd[1:]...), nil
+}
+
+type Gateway struct {
+ ContainerUUID string
+ Address string // listen host:port; if port=0, Start() will change it to the selected port
+ AuthSecret string
+ Target GatewayTarget
+ Log interface {
+ Printf(fmt string, args ...interface{})
+ }
+
+ sshConfig ssh.ServerConfig
+ requestAuth string
+ respondAuth string
+}
+
+// Start starts an http server that allows authenticated clients to open an
+// interactive "docker exec" session and (in future) connect to tcp ports
+// inside the docker container.
+func (gw *Gateway) Start() error {
+ gw.sshConfig = ssh.ServerConfig{
NoClientAuth: true,
PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
- if c.User() == "root" {
+ if c.User() == "_" {
return nil, nil
- } else {
- return nil, fmt.Errorf("unimplemented: cannot log in as non-root user %q", c.User())
}
+ return nil, fmt.Errorf("cannot specify user %q via ssh client", c.User())
},
PublicKeyCallback: func(c ssh.ConnMetadata, pubKey ssh.PublicKey) (*ssh.Permissions, error) {
- if c.User() == "root" {
+ if c.User() == "_" {
return &ssh.Permissions{
Extensions: map[string]string{
"pubkey-fp": ssh.FingerprintSHA256(pubKey),
},
}, nil
- } else {
- return nil, fmt.Errorf("unimplemented: cannot log in as non-root user %q", c.User())
}
+ return nil, fmt.Errorf("cannot specify user %q via ssh client", c.User())
},
}
- pvt, err := rsa.GenerateKey(rand.Reader, 4096)
+ pvt, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
return err
}
if err != nil {
return err
}
- runner.gatewaySSHConfig.AddHostKey(signer)
+ gw.sshConfig.AddHostKey(signer)
- // GatewayAddress (provided by arvados-dispatch-cloud) is
+ // Address (typically provided by arvados-dispatch-cloud) is
// HOST:PORT where HOST is our IP address or hostname as seen
// from arvados-controller, and PORT is either the desired
- // port where we should run our gateway server, or "0" if
- // we should choose an available port.
- host, port, err := net.SplitHostPort(os.Getenv("GatewayAddress"))
+ // port where we should run our gateway server, or "0" if we
+ // should choose an available port.
+ host, port, err := net.SplitHostPort(gw.Address)
+ if err != nil {
+ return err
+ }
+ cert, err := selfsigned.CertGenerator{}.Generate()
if err != nil {
return err
}
+ h := hmac.New(sha256.New, []byte(gw.AuthSecret))
+ h.Write(cert.Certificate[0])
+ gw.requestAuth = fmt.Sprintf("%x", h.Sum(nil))
+ h.Reset()
+ h.Write([]byte(gw.requestAuth))
+ gw.respondAuth = fmt.Sprintf("%x", h.Sum(nil))
+
srv := &httpserver.Server{
Server: http.Server{
- Handler: http.HandlerFunc(runner.handleSSH),
+ Handler: http.HandlerFunc(gw.handleSSH),
+ TLSConfig: &tls.Config{
+ Certificates: []tls.Certificate{cert},
+ },
},
Addr: ":" + port,
}
// gateway_address to "HOST:PORT" where HOST is our
// external hostname/IP as provided by arvados-dispatch-cloud,
// and PORT is the port number we ended up listening on.
- runner.gatewayAddress = net.JoinHostPort(host, port)
+ gw.Address = net.JoinHostPort(host, port)
return nil
}
-// handleSSH connects to an SSH server that runs commands as root in
-// the container. The tunnel itself can only be created by an
+// handleSSH connects to an SSH server that allows the caller to run
+// interactive commands as root (or any other desired user) inside the
+// container. The tunnel itself can only be created by an
// authenticated caller, so the SSH server itself is wide open (any
// password or key will be accepted).
//
// Connection: upgrade
// Upgrade: ssh
// X-Arvados-Target-Uuid: uuid of container
-// X-Arvados-Authorization: must match GatewayAuthSecret provided by
-// a-d-c (this prevents other containers and shell nodes from
-// connecting directly)
+// X-Arvados-Authorization: must match
+// hmac(AuthSecret,certfingerprint) (this prevents other containers
+// and shell nodes from connecting directly)
//
-// Optional header:
+// Optional headers:
//
-// X-Arvados-Detach-Keys: argument to "docker attach --detach-keys",
+// X-Arvados-Detach-Keys: argument to "docker exec --detach-keys",
// e.g., "ctrl-p,ctrl-q"
-func (runner *ContainerRunner) handleSSH(w http.ResponseWriter, req *http.Request) {
+// X-Arvados-Login-Username: argument to "docker exec --user": account
+// used to run command(s) inside the container.
+func (gw *Gateway) handleSSH(w http.ResponseWriter, req *http.Request) {
// In future we'll handle browser traffic too, but for now the
// only traffic we expect is an SSH tunnel from
// (*lib/controller/localdb.Conn)ContainerSSH()
http.Error(w, "path not found", http.StatusNotFound)
return
}
- if want := req.Header.Get("X-Arvados-Target-Uuid"); want != runner.Container.UUID {
- http.Error(w, fmt.Sprintf("misdirected request: meant for %q but received by crunch-run %q", want, runner.Container.UUID), http.StatusBadGateway)
+ if want := req.Header.Get("X-Arvados-Target-Uuid"); want != gw.ContainerUUID {
+ http.Error(w, fmt.Sprintf("misdirected request: meant for %q but received by crunch-run %q", want, gw.ContainerUUID), http.StatusBadGateway)
return
}
- if req.Header.Get("X-Arvados-Authorization") != runner.gatewayAuthSecret {
+ if req.Header.Get("X-Arvados-Authorization") != gw.requestAuth {
http.Error(w, "bad X-Arvados-Authorization header", http.StatusUnauthorized)
return
}
detachKeys := req.Header.Get("X-Arvados-Detach-Keys")
+ username := req.Header.Get("X-Arvados-Login-Username")
+ if username == "" {
+ username = "root"
+ }
hj, ok := w.(http.Hijacker)
if !ok {
http.Error(w, "ResponseWriter does not support connection upgrade", http.StatusInternalServerError)
defer netconn.Close()
w.Header().Set("Connection", "upgrade")
w.Header().Set("Upgrade", "ssh")
+ w.Header().Set("X-Arvados-Authorization-Response", gw.respondAuth)
netconn.Write([]byte("HTTP/1.1 101 Switching Protocols\r\n"))
w.Header().Write(netconn)
netconn.Write([]byte("\r\n"))
ctx := req.Context()
- conn, newchans, reqs, err := ssh.NewServerConn(netconn, runner.gatewaySSHConfig)
+ conn, newchans, reqs, err := ssh.NewServerConn(netconn, &gw.sshConfig)
if err != nil {
- runner.CrunchLog.Printf("ssh.NewServerConn: %s", err)
+ gw.Log.Printf("ssh.NewServerConn: %s", err)
return
}
defer conn.Close()
go ssh.DiscardRequests(reqs)
for newch := range newchans {
- if newch.ChannelType() != "session" {
- newch.Reject(ssh.UnknownChannelType, "unknown channel type")
- 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()
- if err != nil {
- runner.CrunchLog.Printf("accept channel: %s", err)
- return
- }
- var pty0, tty0 *os.File
- go func() {
- defer pty0.Close()
- defer tty0.Close()
- // 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)
- 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, runner.ContainerID)
- cmd.Args = append(cmd.Args, execargs...)
- cmd.SysProcAttr = &syscall.SysProcAttr{
- Setctty: tty0 != nil,
- Setsid: true,
- }
- cmd.Env = append(os.Environ(), termEnv...)
- err := cmd.Run()
- errClose := ch.CloseWrite()
- var resp struct {
- Status uint32
- }
- if err, ok := err.(*exec.ExitError); ok {
- if status, ok := err.Sys().(syscall.WaitStatus); ok {
- resp.Status = uint32(status.ExitStatus())
- }
- }
- 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
- }
- 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
+ }
+}
+
+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
+ }
+
+ dstaddr, err := gw.Target.IPAddress()
+ if err != nil {
+ fmt.Fprintf(ch.Stderr(), "container has no IP address: %s\n", err)
+ return
+ } else 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() {
+ var resp struct {
+ Status uint32
+ }
+ defer func() {
+ ch.SendRequest("exit-status", false, ssh.Marshal(&resp))
+ ch.Close()
+ }()
+
+ cmd, err := gw.Target.InjectCommand(ctx, detachKeys, username, tty0 != nil, execargs)
+ if err != nil {
+ fmt.Fprintln(ch.Stderr(), err)
+ ch.CloseWrite()
+ resp.Status = 1
+ return
+ }
+ cmd.Stdin = ch
+ cmd.Stdout = ch
+ cmd.Stderr = ch.Stderr()
+ if tty0 != nil {
+ 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.SysProcAttr = &syscall.SysProcAttr{
+ Setctty: tty0 != nil,
+ Setsid: true,
+ }
+ cmd.Env = append(os.Environ(), termEnv...)
+ err = cmd.Run()
+ 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
}
+ }()
+ 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)
+ }
}
}
projects / arvados.git / blobdiff