sshportal/main.go
2017-12-04 11:14:20 +01:00

274 lines
7.3 KiB
Go

package main
import (
"errors"
"fmt"
"log"
"math/rand"
"os"
"path"
"strings"
"time"
"github.com/gliderlabs/ssh"
"github.com/jinzhu/gorm"
_ "github.com/jinzhu/gorm/dialects/mysql"
_ "github.com/jinzhu/gorm/dialects/sqlite"
"github.com/urfave/cli"
gossh "golang.org/x/crypto/ssh"
)
var (
// Version should be updated by hand at each release
Version = "1.5.0+dev"
// GitTag will be overwritten automatically by the build system
GitTag string
// GitSha will be overwritten automatically by the build system
GitSha string
// GitBranch will be overwritten automatically by the build system
GitBranch string
)
type sshportalContextKey string
var (
userContextKey = sshportalContextKey("user")
messageContextKey = sshportalContextKey("message")
errorContextKey = sshportalContextKey("error")
)
func main() {
rand.Seed(time.Now().UnixNano())
app := cli.NewApp()
app.Name = path.Base(os.Args[0])
app.Author = "Manfred Touron"
app.Version = Version + " (" + GitSha + ")"
app.Email = "https://github.com/moul/sshportal"
app.Flags = []cli.Flag{
cli.StringFlag{
Name: "bind-address, b",
EnvVar: "SSHPORTAL_BIND",
Value: ":2222",
Usage: "SSH server bind address",
},
cli.StringFlag{
Name: "db-driver",
Value: "sqlite3",
Usage: "GORM driver (sqlite3)",
},
cli.StringFlag{
Name: "db-conn",
Value: "./sshportal.db",
Usage: "GORM connection string",
},
cli.BoolFlag{
Name: "debug, D",
Usage: "Display debug information",
},
cli.StringFlag{
Name: "config-user",
Usage: "SSH user that spawns a configuration shell",
Value: "admin",
},
cli.StringFlag{
Name: "healthcheck-user",
Usage: "SSH user that returns healthcheck status without checking the SSH key",
Value: "healthcheck",
},
cli.StringFlag{
Name: "aes-key",
Usage: "Encrypt sensitive data in database (length: 16, 24 or 32)",
},
}
app.Action = server
if err := app.Run(os.Args); err != nil {
log.Fatalf("error: %v", err)
}
}
func server(c *cli.Context) error {
switch len(c.String("aes-key")) {
case 0, 16, 24, 32:
default:
return fmt.Errorf("invalid aes key size, should be 16 or 24, 32")
}
// db
db, err := gorm.Open(c.String("db-driver"), c.String("db-conn"))
if err != nil {
return err
}
defer func() {
if err2 := db.Close(); err2 != nil {
panic(err2)
}
}()
if err = db.DB().Ping(); err != nil {
return err
}
if c.Bool("debug") {
db.LogMode(true)
}
if err := dbInit(db); err != nil {
return err
}
// ssh server
ssh.Handle(func(s ssh.Session) {
currentUser := s.Context().Value(userContextKey).(User)
log.Printf("New connection: sshUser=%q remote=%q local=%q command=%q dbUser=id:%q,email:%s", s.User(), s.RemoteAddr(), s.LocalAddr(), s.Command(), currentUser.ID, currentUser.Email)
if err := s.Context().Value(errorContextKey); err != nil {
fmt.Fprintf(s, "error: %v\n", err)
return
}
if msg := s.Context().Value(messageContextKey); msg != nil {
fmt.Fprint(s, msg.(string))
}
switch username := s.User(); {
case username == c.String("healthcheck-user"):
fmt.Fprintln(s, "OK")
return
case username == currentUser.Name || username == currentUser.Email || username == c.String("config-user"):
if err := shell(c, s, s.Command(), db); err != nil {
fmt.Fprintf(s, "error: %v\n", err)
}
case strings.HasPrefix(username, "invite:"):
return
default:
host, err := RemoteHostFromSession(s, db)
if err != nil {
fmt.Fprintf(s, "error: %v\n", err)
// FIXME: print available hosts
return
}
// load up-to-date objects
// FIXME: cache them or try not to load them
var tmpUser User
if err2 := db.Preload("Groups").Preload("Groups.ACLs").Where("id = ?", currentUser.ID).First(&tmpUser).Error; err2 != nil {
fmt.Fprintf(s, "error: %v\n", err2)
return
}
var tmpHost Host
if err2 := db.Preload("Groups").Preload("Groups.ACLs").Where("id = ?", host.ID).First(&tmpHost).Error; err2 != nil {
fmt.Fprintf(s, "error: %v\n", err2)
return
}
action, err2 := CheckACLs(tmpUser, tmpHost)
if err2 != nil {
fmt.Fprintf(s, "error: %v\n", err2)
return
}
// decrypt key and password
HostDecrypt(c.String("aes-key"), host)
SSHKeyDecrypt(c.String("aes-key"), host.SSHKey)
switch action {
case ACLActionAllow:
sess := Session{
UserID: currentUser.ID,
HostID: host.ID,
Status: SessionStatusActive,
}
if err2 := db.Create(&sess).Error; err2 != nil {
fmt.Fprintf(s, "error: %v\n", err2)
return
}
sessUpdate := Session{}
if err2 := proxy(s, host, DynamicHostKey(db, host)); err2 != nil {
fmt.Fprintf(s, "error: %v\n", err2)
sessUpdate.ErrMsg = fmt.Sprintf("%v", err2)
switch sessUpdate.ErrMsg {
case "lch closed the connection", "rch closed the connection":
sessUpdate.ErrMsg = ""
}
}
sessUpdate.Status = SessionStatusClosed
now := time.Now()
sessUpdate.StoppedAt = &now
db.Model(&sess).Updates(&sessUpdate)
case ACLActionDeny:
fmt.Fprintf(s, "You don't have permission to that host.\n")
default:
fmt.Fprintf(s, "error: invalid ACL action: %q\n", action)
}
}
})
opts := []ssh.Option{}
opts = append(opts, ssh.PublicKeyAuth(func(ctx ssh.Context, key ssh.PublicKey) bool {
var (
userKey UserKey
user User
username = ctx.User()
)
// lookup user by key
db.Where("authorized_key = ?", string(gossh.MarshalAuthorizedKey(key))).First(&userKey)
if userKey.UserID > 0 {
db.Preload("Roles").Where("id = ?", userKey.UserID).First(&user)
if strings.HasPrefix(username, "invite:") {
ctx.SetValue(errorContextKey, fmt.Errorf("invites are only supported for ney SSH keys; your ssh key is already associated with the user %q", user.Email))
}
ctx.SetValue(userContextKey, user)
return true
}
// handle invite "links"
if strings.HasPrefix(username, "invite:") {
inputToken := strings.Split(username, ":")[1]
if len(inputToken) > 0 {
db.Where("invite_token = ?", inputToken).First(&user)
}
if user.ID > 0 {
userKey = UserKey{
UserID: user.ID,
Key: key.Marshal(),
Comment: "created by sshportal",
AuthorizedKey: string(gossh.MarshalAuthorizedKey(key)),
}
db.Create(&userKey)
// token is only usable once
user.InviteToken = ""
db.Model(&user).Updates(&user)
ctx.SetValue(messageContextKey, fmt.Sprintf("Welcome %s!\n\nYour key is now associated with the user %q.\n", user.Name, user.Email))
ctx.SetValue(userContextKey, user)
} else {
ctx.SetValue(userContextKey, User{Name: "Anonymous"})
ctx.SetValue(errorContextKey, errors.New("your token is invalid or expired"))
}
return true
}
// fallback
ctx.SetValue(errorContextKey, errors.New("unknown ssh key"))
ctx.SetValue(userContextKey, User{Name: "Anonymous"})
return true
}))
opts = append(opts, func(srv *ssh.Server) error {
var key SSHKey
if err := SSHKeysByIdentifiers(db, []string{"host"}).First(&key).Error; err != nil {
return err
}
SSHKeyDecrypt(c.String("aes-key"), &key)
signer, err := gossh.ParsePrivateKey([]byte(key.PrivKey))
if err != nil {
return err
}
srv.AddHostKey(signer)
return nil
})
log.Printf("info: SSH Server accepting connections on %s", c.String("bind-address"))
return ssh.ListenAndServe(c.String("bind-address"), nil, opts...)
}