nebula/ssh.go

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2019-11-19 10:00:20 -07:00
package nebula
import (
"bytes"
"encoding/json"
"flag"
"fmt"
"github.com/sirupsen/logrus"
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"github.com/slackhq/nebula/sshd"
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"io/ioutil"
"net"
"os"
"reflect"
"runtime/pprof"
"strings"
"syscall"
)
type sshListHostMapFlags struct {
Json bool
Pretty bool
}
type sshPrintCertFlags struct {
Json bool
Pretty bool
}
type sshPrintTunnelFlags struct {
Pretty bool
}
type sshChangeRemoteFlags struct {
Address string
}
type sshCloseTunnelFlags struct {
LocalOnly bool
}
type sshCreateTunnelFlags struct {
Address string
}
func wireSSHReload(ssh *sshd.SSHServer, c *Config) {
c.RegisterReloadCallback(func(c *Config) {
if c.GetBool("sshd.enabled", false) {
err := configSSH(ssh, c)
if err != nil {
l.WithError(err).Error("Failed to reconfigure the sshd")
ssh.Stop()
}
} else {
ssh.Stop()
}
})
}
func configSSH(ssh *sshd.SSHServer, c *Config) error {
//TODO conntrack list
//TODO print firewall rules or hash?
listen := c.GetString("sshd.listen", "")
if listen == "" {
return fmt.Errorf("sshd.listen must be provided")
}
port := strings.Split(listen, ":")
if len(port) < 2 {
return fmt.Errorf("sshd.listen does not have a port")
} else if port[1] == "22" {
return fmt.Errorf("sshd.listen can not use port 22")
}
//TODO: no good way to reload this right now
hostKeyFile := c.GetString("sshd.host_key", "")
if hostKeyFile == "" {
return fmt.Errorf("sshd.host_key must be provided")
}
hostKeyBytes, err := ioutil.ReadFile(hostKeyFile)
if err != nil {
return fmt.Errorf("error while loading sshd.host_key file: %s", err)
}
err = ssh.SetHostKey(hostKeyBytes)
if err != nil {
return fmt.Errorf("error while adding sshd.host_key: %s", err)
}
rawKeys := c.Get("sshd.authorized_users")
keys, ok := rawKeys.([]interface{})
if ok {
for _, rk := range keys {
kDef, ok := rk.(map[interface{}]interface{})
if !ok {
l.WithField("sshKeyConfig", rk).Warn("Authorized user had an error, ignoring")
continue
}
user, ok := kDef["user"].(string)
if !ok {
l.WithField("sshKeyConfig", rk).Warn("Authorized user is missing the user field")
continue
}
k := kDef["keys"]
switch v := k.(type) {
case string:
err := ssh.AddAuthorizedKey(user, v)
if err != nil {
l.WithError(err).WithField("sshKeyConfig", rk).WithField("sshKey", v).Warn("Failed to authorize key")
continue
}
case []interface{}:
for _, subK := range v {
sk, ok := subK.(string)
if !ok {
l.WithField("sshKeyConfig", rk).WithField("sshKey", subK).Warn("Did not understand ssh key")
continue
}
err := ssh.AddAuthorizedKey(user, sk)
if err != nil {
l.WithError(err).WithField("sshKeyConfig", sk).Warn("Failed to authorize key")
continue
}
}
default:
l.WithField("sshKeyConfig", rk).Warn("Authorized user is missing the keys field or was not understood")
}
}
} else {
l.Info("no ssh users to authorize")
}
if c.GetBool("sshd.enabled", false) {
ssh.Stop()
go ssh.Run(listen)
} else {
ssh.Stop()
}
return nil
}
func attachCommands(ssh *sshd.SSHServer, hostMap *HostMap, pendingHostMap *HostMap, lightHouse *LightHouse, ifce *Interface) {
ssh.RegisterCommand(&sshd.Command{
Name: "list-hostmap",
ShortDescription: "List all known previously connected hosts",
Flags: func() (*flag.FlagSet, interface{}) {
fl := flag.NewFlagSet("", flag.ContinueOnError)
s := sshListHostMapFlags{}
fl.BoolVar(&s.Json, "json", false, "outputs as json with more information")
fl.BoolVar(&s.Pretty, "pretty", false, "pretty prints json, assumes -json")
return fl, &s
},
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshListHostMap(hostMap, fs, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "list-pending-hostmap",
ShortDescription: "List all handshaking hosts",
Flags: func() (*flag.FlagSet, interface{}) {
fl := flag.NewFlagSet("", flag.ContinueOnError)
s := sshListHostMapFlags{}
fl.BoolVar(&s.Json, "json", false, "outputs as json with more information")
fl.BoolVar(&s.Pretty, "pretty", false, "pretty prints json, assumes -json")
return fl, &s
},
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshListHostMap(pendingHostMap, fs, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "list-lighthouse-addrmap",
ShortDescription: "List all lighthouse map entries",
Flags: func() (*flag.FlagSet, interface{}) {
fl := flag.NewFlagSet("", flag.ContinueOnError)
s := sshListHostMapFlags{}
fl.BoolVar(&s.Json, "json", false, "outputs as json with more information")
fl.BoolVar(&s.Pretty, "pretty", false, "pretty prints json, assumes -json")
return fl, &s
},
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshListLighthouseMap(lightHouse, fs, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "reload",
ShortDescription: "Reloads configuration from disk, same as sending HUP to the process",
Callback: sshReload,
})
ssh.RegisterCommand(&sshd.Command{
Name: "start-cpu-profile",
ShortDescription: "Starts a cpu profile and write output to the provided file",
Callback: sshStartCpuProfile,
})
ssh.RegisterCommand(&sshd.Command{
Name: "stop-cpu-profile",
ShortDescription: "Stops a cpu profile and writes output to the previously provided file",
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
pprof.StopCPUProfile()
return w.WriteLine("If a CPU profile was running it is now stopped")
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "save-heap-profile",
ShortDescription: "Saves a heap profile to the provided path",
Callback: sshGetHeapProfile,
})
ssh.RegisterCommand(&sshd.Command{
Name: "log-level",
ShortDescription: "Gets or sets the current log level",
Callback: sshLogLevel,
})
ssh.RegisterCommand(&sshd.Command{
Name: "log-format",
ShortDescription: "Gets or sets the current log format",
Callback: sshLogFormat,
})
ssh.RegisterCommand(&sshd.Command{
Name: "version",
ShortDescription: "Prints the currently running version of nebula",
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshVersion(ifce, fs, a, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "print-cert",
ShortDescription: "Prints the current certificate being used or the certificate for the provided vpn ip",
Flags: func() (*flag.FlagSet, interface{}) {
fl := flag.NewFlagSet("", flag.ContinueOnError)
s := sshPrintCertFlags{}
fl.BoolVar(&s.Json, "json", false, "outputs as json")
fl.BoolVar(&s.Pretty, "pretty", false, "pretty prints json, assumes -json")
return fl, &s
},
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshPrintCert(ifce, fs, a, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "print-tunnel",
ShortDescription: "Prints json details about a tunnel for the provided vpn ip",
Flags: func() (*flag.FlagSet, interface{}) {
fl := flag.NewFlagSet("", flag.ContinueOnError)
s := sshPrintTunnelFlags{}
fl.BoolVar(&s.Pretty, "pretty", false, "pretty prints json")
return fl, &s
},
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshPrintTunnel(ifce, fs, a, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "change-remote",
ShortDescription: "Changes the remote address used in the tunnel for the provided vpn ip",
Flags: func() (*flag.FlagSet, interface{}) {
fl := flag.NewFlagSet("", flag.ContinueOnError)
s := sshChangeRemoteFlags{}
fl.StringVar(&s.Address, "address", "", "The new remote address, ip:port")
return fl, &s
},
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshChangeRemote(ifce, fs, a, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "close-tunnel",
ShortDescription: "Closes a tunnel for the provided vpn ip",
Flags: func() (*flag.FlagSet, interface{}) {
fl := flag.NewFlagSet("", flag.ContinueOnError)
s := sshCloseTunnelFlags{}
fl.BoolVar(&s.LocalOnly, "local-only", false, "Disables notifying the remote that the tunnel is shutting down")
return fl, &s
},
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshCloseTunnel(ifce, fs, a, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "create-tunnel",
ShortDescription: "Creates a tunnel for the provided vpn ip and address",
Help: "The lighthouses will be queried for real addresses but you can provide one as well.",
Flags: func() (*flag.FlagSet, interface{}) {
fl := flag.NewFlagSet("", flag.ContinueOnError)
s := sshCreateTunnelFlags{}
fl.StringVar(&s.Address, "address", "", "Optionally provide a real remote address, ip:port ")
return fl, &s
},
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshCreateTunnel(ifce, fs, a, w)
},
})
ssh.RegisterCommand(&sshd.Command{
Name: "query-lighthouse",
ShortDescription: "Query the lighthouses for the provided vpn ip",
Help: "This command is asynchronous. Only currently known udp ips will be printed.",
Callback: func(fs interface{}, a []string, w sshd.StringWriter) error {
return sshQueryLighthouse(ifce, fs, a, w)
},
})
}
func sshListHostMap(hostMap *HostMap, a interface{}, w sshd.StringWriter) error {
fs, ok := a.(*sshListHostMapFlags)
if !ok {
//TODO: error
return nil
}
hostMap.RLock()
defer hostMap.RUnlock()
if fs.Json || fs.Pretty {
js := json.NewEncoder(w.GetWriter())
if fs.Pretty {
js.SetIndent("", " ")
}
d := make([]m, len(hostMap.Hosts))
x := 0
var h m
for _, v := range hostMap.Hosts {
h = m{
"vpnIp": int2ip(v.hostId),
"localIndex": v.localIndexId,
"remoteIndex": v.remoteIndexId,
"remoteAddrs": v.RemoteUDPAddrs(),
"cachedPackets": len(v.packetStore),
"cert": v.GetCert(),
}
if v.ConnectionState != nil {
h["messageCounter"] = v.ConnectionState.messageCounter
}
d[x] = h
x++
}
err := js.Encode(d)
if err != nil {
//TODO
return nil
}
} else {
for i, v := range hostMap.Hosts {
err := w.WriteLine(fmt.Sprintf("%s: %s", int2ip(i), v.RemoteUDPAddrs()))
if err != nil {
return err
}
}
}
return nil
}
func sshListLighthouseMap(lightHouse *LightHouse, a interface{}, w sshd.StringWriter) error {
fs, ok := a.(*sshListHostMapFlags)
if !ok {
//TODO: error
return nil
}
lightHouse.RLock()
defer lightHouse.RUnlock()
if fs.Json || fs.Pretty {
js := json.NewEncoder(w.GetWriter())
if fs.Pretty {
js.SetIndent("", " ")
}
d := make([]m, len(lightHouse.addrMap))
x := 0
var h m
for vpnIp, v := range lightHouse.addrMap {
ips := make([]string, len(v))
for i, ip := range v {
ips[i] = ip.String()
}
h = m{
"vpnIp": int2ip(vpnIp),
"addrs": ips,
}
d[x] = h
x++
}
err := js.Encode(d)
if err != nil {
//TODO
return nil
}
} else {
for vpnIp, v := range lightHouse.addrMap {
ips := make([]string, len(v))
for i, ip := range v {
ips[i] = ip.String()
}
err := w.WriteLine(fmt.Sprintf("%s: %s", int2ip(vpnIp), ips))
if err != nil {
return err
}
}
}
return nil
}
func sshStartCpuProfile(fs interface{}, a []string, w sshd.StringWriter) error {
if len(a) == 0 {
err := w.WriteLine("No path to write profile provided")
return err
}
file, err := os.Create(a[0])
if err != nil {
err = w.WriteLine(fmt.Sprintf("Unable to create profile file: %s", err))
return err
}
err = pprof.StartCPUProfile(file)
if err != nil {
err = w.WriteLine(fmt.Sprintf("Unable to start cpu profile: %s", err))
return err
}
err = w.WriteLine(fmt.Sprintf("Started cpu profile, issue stop-cpu-profile to write the output to %s", a))
return err
}
func sshVersion(ifce *Interface, fs interface{}, a []string, w sshd.StringWriter) error {
return w.WriteLine(fmt.Sprintf("%s", ifce.version))
}
func sshQueryLighthouse(ifce *Interface, fs interface{}, a []string, w sshd.StringWriter) error {
if len(a) == 0 {
return w.WriteLine("No vpn ip was provided")
}
vpnIp := ip2int(net.ParseIP(a[0]))
if vpnIp == 0 {
return w.WriteLine(fmt.Sprintf("The provided vpn ip could not be parsed: %s", a[0]))
}
ips, _ := ifce.lightHouse.Query(vpnIp, ifce)
return json.NewEncoder(w.GetWriter()).Encode(ips)
}
func sshCloseTunnel(ifce *Interface, fs interface{}, a []string, w sshd.StringWriter) error {
flags, ok := fs.(*sshCloseTunnelFlags)
if !ok {
//TODO: error
return nil
}
if len(a) == 0 {
return w.WriteLine("No vpn ip was provided")
}
vpnIp := ip2int(net.ParseIP(a[0]))
if vpnIp == 0 {
return w.WriteLine(fmt.Sprintf("The provided vpn ip could not be parsed: %s", a[0]))
}
hostInfo, err := ifce.hostMap.QueryVpnIP(uint32(vpnIp))
if err != nil {
return w.WriteLine(fmt.Sprintf("Could not find tunnel for vpn ip: %v", a[0]))
}
if !flags.LocalOnly {
ifce.send(
closeTunnel,
0,
hostInfo.ConnectionState,
hostInfo,
hostInfo.remote,
[]byte{},
make([]byte, 12, 12),
make([]byte, mtu),
)
}
ifce.closeTunnel(hostInfo)
return w.WriteLine("Closed")
}
func sshCreateTunnel(ifce *Interface, fs interface{}, a []string, w sshd.StringWriter) error {
flags, ok := fs.(*sshCreateTunnelFlags)
if !ok {
//TODO: error
return nil
}
if len(a) == 0 {
return w.WriteLine("No vpn ip was provided")
}
vpnIp := ip2int(net.ParseIP(a[0]))
if vpnIp == 0 {
return w.WriteLine(fmt.Sprintf("The provided vpn ip could not be parsed: %s", a[0]))
}
hostInfo, _ := ifce.hostMap.QueryVpnIP(uint32(vpnIp))
if hostInfo != nil {
return w.WriteLine(fmt.Sprintf("Tunnel already exists"))
}
hostInfo, _ = ifce.handshakeManager.pendingHostMap.QueryVpnIP(uint32(vpnIp))
if hostInfo != nil {
return w.WriteLine(fmt.Sprintf("Tunnel already handshaking"))
}
var addr *udpAddr
if flags.Address != "" {
addr = NewUDPAddrFromString(flags.Address)
if addr == nil {
return w.WriteLine("Address could not be parsed")
}
}
hostInfo = ifce.handshakeManager.AddVpnIP(vpnIp)
if addr != nil {
hostInfo.SetRemote(*addr)
}
ifce.getOrHandshake(vpnIp)
return w.WriteLine("Created")
}
func sshChangeRemote(ifce *Interface, fs interface{}, a []string, w sshd.StringWriter) error {
flags, ok := fs.(*sshChangeRemoteFlags)
if !ok {
//TODO: error
return nil
}
if len(a) == 0 {
return w.WriteLine("No vpn ip was provided")
}
if flags.Address == "" {
return w.WriteLine("No address was provided")
}
addr := NewUDPAddrFromString(flags.Address)
if addr == nil {
return w.WriteLine("Address could not be parsed")
}
vpnIp := ip2int(net.ParseIP(a[0]))
if vpnIp == 0 {
return w.WriteLine(fmt.Sprintf("The provided vpn ip could not be parsed: %s", a[0]))
}
hostInfo, err := ifce.hostMap.QueryVpnIP(uint32(vpnIp))
if err != nil {
return w.WriteLine(fmt.Sprintf("Could not find tunnel for vpn ip: %v", a[0]))
}
hostInfo.SetRemote(*addr)
return w.WriteLine("Changed")
}
func sshGetHeapProfile(fs interface{}, a []string, w sshd.StringWriter) error {
if len(a) == 0 {
return w.WriteLine("No path to write profile provided")
}
file, err := os.Create(a[0])
if err != nil {
err = w.WriteLine(fmt.Sprintf("Unable to create profile file: %s", err))
return err
}
err = pprof.WriteHeapProfile(file)
if err != nil {
err = w.WriteLine(fmt.Sprintf("Unable to write profile: %s", err))
return err
}
err = w.WriteLine(fmt.Sprintf("Mem profile created at %s", a))
return err
}
func sshLogLevel(fs interface{}, a []string, w sshd.StringWriter) error {
if len(a) == 0 {
return w.WriteLine(fmt.Sprintf("Log level is: %s", l.Level))
}
level, err := logrus.ParseLevel(a[0])
if err != nil {
return w.WriteLine(fmt.Sprintf("Unknown log level %s. Possible log levels: %s", a, logrus.AllLevels))
}
l.SetLevel(level)
return w.WriteLine(fmt.Sprintf("Log level is: %s", l.Level))
}
func sshLogFormat(fs interface{}, a []string, w sshd.StringWriter) error {
if len(a) == 0 {
return w.WriteLine(fmt.Sprintf("Log format is: %s", reflect.TypeOf(l.Formatter)))
}
logFormat := strings.ToLower(a[0])
switch logFormat {
case "text":
l.Formatter = &logrus.TextFormatter{}
case "json":
l.Formatter = &logrus.JSONFormatter{}
default:
return fmt.Errorf("unknown log format `%s`. possible formats: %s", logFormat, []string{"text", "json"})
}
return w.WriteLine(fmt.Sprintf("Log format is: %s", reflect.TypeOf(l.Formatter)))
}
func sshPrintCert(ifce *Interface, fs interface{}, a []string, w sshd.StringWriter) error {
args, ok := fs.(*sshPrintCertFlags)
if !ok {
//TODO: error
return nil
}
cert := ifce.certState.certificate
if len(a) > 0 {
vpnIp := ip2int(net.ParseIP(a[0]))
if vpnIp == 0 {
return w.WriteLine(fmt.Sprintf("The provided vpn ip could not be parsed: %s", a[0]))
}
hostInfo, err := ifce.hostMap.QueryVpnIP(uint32(vpnIp))
if err != nil {
return w.WriteLine(fmt.Sprintf("Could not find tunnel for vpn ip: %v", a[0]))
}
cert = hostInfo.GetCert()
}
if args.Json || args.Pretty {
b, err := cert.MarshalJSON()
if err != nil {
//TODO: handle it
return nil
}
if args.Pretty {
buf := new(bytes.Buffer)
err := json.Indent(buf, b, "", " ")
b = buf.Bytes()
if err != nil {
//TODO: handle it
return nil
}
}
return w.WriteBytes(b)
}
return w.WriteLine(cert.String())
}
func sshPrintTunnel(ifce *Interface, fs interface{}, a []string, w sshd.StringWriter) error {
args, ok := fs.(*sshPrintTunnelFlags)
if !ok {
//TODO: error
return nil
}
if len(a) == 0 {
return w.WriteLine("No vpn ip was provided")
}
vpnIp := ip2int(net.ParseIP(a[0]))
if vpnIp == 0 {
return w.WriteLine(fmt.Sprintf("The provided vpn ip could not be parsed: %s", a[0]))
}
hostInfo, err := ifce.hostMap.QueryVpnIP(uint32(vpnIp))
if err != nil {
return w.WriteLine(fmt.Sprintf("Could not find tunnel for vpn ip: %v", a[0]))
}
enc := json.NewEncoder(w.GetWriter())
if args.Pretty {
enc.SetIndent("", " ")
}
return enc.Encode(hostInfo)
}
func sshReload(fs interface{}, a []string, w sshd.StringWriter) error {
p, err := os.FindProcess(os.Getpid())
if err != nil {
return w.WriteLine(err.Error())
//TODO
}
err = p.Signal(syscall.SIGHUP)
if err != nil {
return w.WriteLine(err.Error())
//TODO
}
return w.WriteLine("HUP sent")
}