Add SSH server user config type flag

cmd/commands/server.go

@@ -4,6 +4,7 @@ package cmd
 
 import (
 	"fmt"
+	"strings"
 	"time"
 
 	cssh "github.com/miguelmota/cointop/pkg/ssh"
@@ -19,6 +20,7 @@ func ServerCmd() *cobra.Command {
 	var maxSessions uint = 0
 	var executableBinary string = "cointop"
 	var hostKeyFile string = cssh.DefaultHostKeyFile
+	var userConfigType string = cssh.UserConfigTypePublicKey
 
 	serverCmd := &cobra.Command{
 		Use:   "server",
@@ -33,6 +35,7 @@ func ServerCmd() *cobra.Command {
 				MaxSessions:      maxSessions,
 				ExecutableBinary: executableBinary,
 				HostKeyFile:      hostKeyFile,
+				UserConfigType:   userConfigType,
 			})
 
 			fmt.Printf("Running SSH server on port %v\n", port)
@@ -47,6 +50,7 @@ func ServerCmd() *cobra.Command {
 	serverCmd.Flags().UintVarP(&maxSessions, "max-sessions", "", maxSessions, "Max number of sessions allowed. Default is 0 for unlimited.")
 	serverCmd.Flags().StringVarP(&executableBinary, "binary", "b", executableBinary, "Executable binary path")
 	serverCmd.Flags().StringVarP(&hostKeyFile, "host-key-file", "k", hostKeyFile, "Host key file")
+	serverCmd.Flags().StringVarP(&userConfigType, "user-config-type", "", userConfigType, fmt.Sprintf("User config type. Options are: %s", strings.Join(cssh.UserConfigTypes, ",")))
 
 	return serverCmd
 }

docs/content/faq.md

@@ -400,6 +400,20 @@ draft: false
 
   The public SSH instance is for demo use or short-term usage and will disconnect users after an idle timeout to allow other users to try it out.
 
+## How do I fix the error `SSH key is required to start server` when trying to run SSH server?
+
+  Generate the SSH key if the host machine doesn't have one:
+
+  ```bash
+  $ ssh-keygen
+  ```
+
+  Make sure the host key flag points to the location of the SSH key:
+
+  ```bash
+  cointop server -k ~/.ssh/id_rsa [...]
+  ```
+
 ## Why doesn't the version number work when I install with `go get`?
 
   The version number is read from the git tag during the build process but this requires the `GO111MODULE` environment variable to be set in order for Go to read the build information:

docs/content/install.md

@@ -189,6 +189,12 @@ cointop is available on [Docker Hub](https://hub.docker.com/r/cointop/cointop).
 docker run -it cointop/cointop
 ```
 
+Note: the config is under `/root/.config/cointop` in container, so attach a volume to make it persistent in host:
+
+```bash
+docker run -v ~/.cache/cointop:/root/.config/cointop -it cointop/cointop
+```
+
 ## Binaries
 
 You can find pre-built binaries on the [releases](https://github.com/miguelmota/cointop/releases) page.

docs/content/ssh.md

@@ -5,32 +5,69 @@ draft: false
 ---
 # SSH Server
 
+The SSH server requires that the host has SSH keys, so generate SSH keys if not already:
+
+```bash
+$ ssh-keygen
+```
+
+Check keys were generated:
+
+```bash
+$ ls ~/.ssh
+id_rsa id_rsa.pub
+```
+
 Run SSH server:
 
 ```bash
 cointop server -p 2222
 ```
 
+If the host SSH keys live elsewhere, specify the location:
+
+```bash
+cointop server -p 2222 -k ~/.ssh/some-dir/id_rsa
+```
+
 SSH into server to see cointop:
 
 ```bash
 ssh localhost -p 2222
 ```
 
-SSH demo:
+The cointop SSH server will use the client's public SSH key as the identifier for persistent config by default. You may change it to use the username instead:
 
 ```bash
-ssh cointop.sh
+cointop server -p 2222 --user-config-type=username
 ```
 
-Passing arguments to SSH server:
+SSH'ing into server with same username will use the same respective config now:
 
 ```bash
-ssh cointop.sh -t cointop --colorscheme synthwave
+ssh alice@localhost -p 2222
 ```
 
-Using docker to run SSH server:
+Pass arguments to cointop on SSH server by using SSH `-t` flag followed by cointop command and arguments. For example:
+
+```bash
+ssh localhost -p 2222 -t cointop --colorscheme synthwave
+```
+
+## Using docker to run SSH server:
 
 ```bash
 docker run -p 2222:22 -v ~/.ssh:/keys --entrypoint cointop -it cointop/cointop server -k /keys/id_rsa
 ```
+
+cointop server writes the client config to `/tmp/cointop_config` within the container, so to make it persistent in host attach a volume. The following example will to write the cached config to `~/.cache/cointop` on the host:
+
+```bash
+docker run -p 2222:22 -v ~/.ssh:/keys -v ~/.cache/cointop:/tmp/cointop_config --entrypoint cointop -it cointop/cointop server -k /keys/id_rsa
+```
+
+## SSH demo
+
+```bash
+ssh cointop.sh
+```

pkg/ssh/server.go

@@ -11,6 +11,7 @@ import (
 	"io/ioutil"
 	"os"
 	"os/exec"
+	"strings"
 	"syscall"
 	"time"
 	"unsafe"
@@ -24,6 +25,17 @@ import (
 // DefaultHostKeyFile is default SSH key path
 var DefaultHostKeyFile = "~/.ssh/id_rsa"
 
+// UserConfigTypePublicKey is constant
+var UserConfigTypePublicKey = "public-key"
+
+// UserConfigTypeUsername is constant
+var UserConfigTypeUsername = "username"
+
+// UserConfigTypeNone is constant
+var UserConfigTypeNone = "none"
+
+var UserConfigTypes = []string{UserConfigTypePublicKey, UserConfigTypeUsername, UserConfigTypeNone}
+
 // Config is config struct
 type Config struct {
 	Port             uint
@@ -33,6 +45,7 @@ type Config struct {
 	ExecutableBinary string
 	HostKeyFile      string
 	MaxSessions      uint
+	UserConfigType   string
 }
 
 // Server is server struct
@@ -46,6 +59,7 @@ type Server struct {
 	hostKeyFile      string
 	maxSessions      uint
 	sessionCount     uint
+	userConfigType   string
 }
 
 // NewServer returns a new server instance
@@ -54,7 +68,11 @@ func NewServer(config *Config) *Server {
 	if config.HostKeyFile != "" {
 		hostKeyFile = config.HostKeyFile
 	}
-
+	userConfigType := config.UserConfigType
+	if userConfigType == "" {
+		userConfigType = UserConfigTypePublicKey
+	}
+	validateUserConfigType(userConfigType)
 	hostKeyFile = pathutil.NormalizePath(hostKeyFile)
 	return &Server{
 		port:             config.Port,
@@ -64,6 +82,7 @@ func NewServer(config *Config) *Server {
 		executableBinary: config.ExecutableBinary,
 		hostKeyFile:      hostKeyFile,
 		maxSessions:      config.MaxSessions,
+		userConfigType:   userConfigType,
 	}
 }
 
@@ -95,18 +114,32 @@ func (s *Server) ListenAndServe() error {
 			}
 
 			configDir := ""
-			pubKey := sshSession.PublicKey()
-			if pubKey != nil {
-				pubBytes := pubKey.Marshal()
-				if len(pubBytes) > 0 {
-					hash := sha256.Sum256(pubBytes)
-					configDir = fmt.Sprintf("/tmp/cointop_config/%x", hash)
-					err := os.MkdirAll(configDir, 0700)
-					if err != nil {
-						fmt.Println(err)
-						return
+			configDirKey := ""
+
+			switch s.userConfigType {
+			case UserConfigTypePublicKey:
+				pubKey := sshSession.PublicKey()
+				if pubKey != nil {
+					pubBytes := pubKey.Marshal()
+					if len(pubBytes) > 0 {
+						hash := sha256.Sum256(pubBytes)
+						configDirKey = fmt.Sprintf("%x", hash)
 					}
 				}
+			case UserConfigTypeUsername:
+				user := sshSession.User()
+				if user != "" {
+					configDirKey = user
+				}
+			}
+
+			if configDirKey != "" {
+				configDir = fmt.Sprintf("/tmp/cointop_config/%s", configDirKey)
+				err := os.MkdirAll(configDir, 0700)
+				if err != nil {
+					fmt.Println(err)
+					return
+				}
 			}
 
 			if configDir == "" {
@@ -209,3 +242,12 @@ func setWinsize(f *os.File, w, h int) {
 func createTempDir() (string, error) {
 	return ioutil.TempDir("", "")
 }
+
+func validateUserConfigType(userConfigType string) {
+	for _, validType := range UserConfigTypes {
+		if validType == userConfigType {
+			return
+		}
+	}
+	panic(fmt.Errorf("invalid user config type. Acceptable values are: %s", strings.Join(UserConfigTypes, ",")))
+}