more on scheduled jobs and ssh callbacks

1 files changed, 4 insertions, 276 deletions

diff --git a/internal/ssh/client/hostkeycallback.go b/internal/ssh/client/hostkeycallback.go
index d090d7f..95543f2 100644
--- a/internal/ssh/client/hostkeycallback.go
+++ b/internal/ssh/client/hostkeycallback.go
@@ -1,287 +1,15 @@
 package client
 
 import (
-	"bufio"
 	"context"
-	"fmt"
-	"net"
-	"os"
-	"strings"
-	"sync"
-	"time"
-
-	"github.com/mimecast/dtail/internal/io/logger"
-	"github.com/mimecast/dtail/internal/io/prompt"
 
 	"golang.org/x/crypto/ssh"
-	"golang.org/x/crypto/ssh/knownhosts"
-)
-
-type response int
-
-const (
-	trustHost     response = iota
-	dontTrustHost response = iota
 )
 
-// Represents an unknown host.
-type unknownHost struct {
-	server     string
-	remote     net.Addr
-	key        ssh.PublicKey
-	hostLine   string
-	ipLine     string
-	responseCh chan response
-}
-
 // HostKeyCallback is a wrapper around ssh.KnownHosts so that we can add all
 // unknown hosts in a single batch to the known_hosts file.
-type HostKeyCallback struct {
-	knownHostsPath  string
-	unknownCh       chan unknownHost
-	throttleCh      chan struct{}
-	trustAllHostsCh chan struct{}
-	untrustedHosts  map[string]bool
-	mutex           sync.Mutex
-}
-
-// NewHostKeyCallback returns a new wrapper.
-func NewHostKeyCallback(knownHostsPath string, trustAllHosts bool, throttleCh chan struct{}) (*HostKeyCallback, error) {
-	// Ensure file exists
-	os.OpenFile(knownHostsPath, os.O_RDONLY|os.O_CREATE, 0666)
-
-	h := HostKeyCallback{
-		knownHostsPath:  knownHostsPath,
-		unknownCh:       make(chan unknownHost),
-		trustAllHostsCh: make(chan struct{}),
-		throttleCh:      throttleCh,
-		untrustedHosts:  make(map[string]bool),
-	}
-
-	if trustAllHosts {
-		close(h.trustAllHostsCh)
-	}
-
-	return &h, nil
-}
-
-// Wrap the host key callback.
-func (h *HostKeyCallback) Wrap() ssh.HostKeyCallback {
-	return func(server string, remote net.Addr, key ssh.PublicKey) error {
-		// Parse known_hosts file
-		knownHostsCb, err := knownhosts.New(h.knownHostsPath)
-		if err != nil {
-			// Problem parsing it
-			return err
-		}
-
-		// Check for valid entry in known_hosts file
-		err = knownHostsCb(server, remote, key)
-		if err == nil {
-			// OK
-			return nil
-		}
-
-		// Make sure that interactive user callback does not interfere with
-		// SSH connection throttler.
-		<-h.throttleCh
-		defer func() { h.throttleCh <- struct{}{} }()
-
-		unknown := unknownHost{
-			server:     server,
-			remote:     remote,
-			key:        key,
-			hostLine:   knownhosts.Line([]string{server}, key),
-			ipLine:     knownhosts.Line([]string{remote.String()}, key),
-			responseCh: make(chan response),
-		}
-
-		logger.Warn("Encountered unknown host", unknown)
-		// Notify user that there is an unknown host
-		h.unknownCh <- unknown
-
-		// Wait for user input.
-		switch <-unknown.responseCh {
-		case trustHost:
-			// End user acknowledged host key
-			return nil
-		case dontTrustHost:
-		}
-
-		h.mutex.Lock()
-		defer h.mutex.Unlock()
-		h.untrustedHosts[server] = true
-
-		return err
-	}
-}
-
-// PromptAddHosts prompts a question to the user whether unknown hosts should
-// be added to the known hosts or not.
-func (h *HostKeyCallback) PromptAddHosts(ctx context.Context) {
-	var hosts []unknownHost
-
-	for {
-		// Check whether there is a unknown host
-		select {
-		case unknown := <-h.unknownCh:
-			hosts = append(hosts, unknown)
-			// Ask every 50 unknown hosts
-			if len(hosts) >= 50 {
-				h.promptAddHosts(hosts)
-				hosts = []unknownHost{}
-			}
-		case <-time.After(2 * time.Second):
-			// Or ask when after 2 seconds no new unknown hosts were added.
-			if len(hosts) > 0 {
-				h.promptAddHosts(hosts)
-				hosts = []unknownHost{}
-			}
-		case <-ctx.Done():
-			logger.Debug("Stopping goroutine prompting new hosts...")
-			return
-		}
-	}
-}
-
-func (h *HostKeyCallback) promptAddHosts(hosts []unknownHost) {
-	var servers []string
-
-	for _, host := range hosts {
-		servers = append(servers, host.server)
-	}
-
-	select {
-	case <-h.trustAllHostsCh:
-		logger.Warn("Trusting host keys of servers", servers)
-		h.trustHosts(hosts)
-		return
-	default:
-	}
-
-	question := fmt.Sprintf("Encountered %d unknown hosts: '%s'\n%s",
-		len(servers),
-		strings.Join(servers, ","),
-		"Do you want to trust these hosts?",
-	)
-
-	p := prompt.New(question)
-
-	a := prompt.Answer{
-		Long:  "yes",
-		Short: "y",
-		Callback: func() {
-			h.trustHosts(hosts)
-		},
-		EndCallback: func() {
-			logger.Info("Added hosts to known hosts file", h.knownHostsPath)
-		},
-	}
-	p.Add(a)
-
-	a = prompt.Answer{
-		Long:  "all",
-		Short: "a",
-		Callback: func() {
-			close(h.trustAllHostsCh)
-			h.trustHosts(hosts)
-		},
-		EndCallback: func() {
-			logger.Info("Added hosts to known hosts file", h.knownHostsPath)
-		},
-	}
-	p.Add(a)
-
-	a = prompt.Answer{
-		Long:  "no",
-		Short: "n",
-		Callback: func() {
-			h.dontTrustHosts(hosts)
-		},
-		EndCallback: func() {
-			logger.Info("Didn't add hosts to known hosts file", h.knownHostsPath)
-		},
-	}
-	p.Add(a)
-
-	a = prompt.Answer{
-		Long:     "details",
-		Short:    "d",
-		AskAgain: true,
-		Callback: func() {
-			for _, unknown := range hosts {
-				fmt.Println(unknown.hostLine)
-				fmt.Println(unknown.ipLine)
-			}
-		},
-	}
-	p.Add(a)
-
-	p.Ask()
-}
-
-func (h *HostKeyCallback) trustHosts(hosts []unknownHost) {
-	tmpKnownHostsPath := fmt.Sprintf("%s.tmp", h.knownHostsPath)
-
-	newFd, err := os.OpenFile(tmpKnownHostsPath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0600)
-	if err != nil {
-		panic(fmt.Sprintf("%s: %s", tmpKnownHostsPath, err.Error()))
-	}
-	defer newFd.Close()
-
-	// Newly trusted hosts in normalized form
-	addresses := make(map[string]struct{})
-
-	// First write to new known hosts file, and keep track of addresses
-	for _, unknown := range hosts {
-		unknown.responseCh <- trustHost
-
-		// Add once as [HOSTNAME]:PORT
-		addresses[knownhosts.Normalize(unknown.server)] = struct{}{}
-		// And once as [IP]:PORT
-		addresses[knownhosts.Normalize(unknown.remote.String())] = struct{}{}
-
-		newFd.WriteString(fmt.Sprintf("%s\n", unknown.hostLine))
-		newFd.WriteString(fmt.Sprintf("%s\n", unknown.ipLine))
-	}
-
-	// Read old known hosts file, to see which are old and new entries
-	os.OpenFile(h.knownHostsPath, os.O_RDONLY|os.O_CREATE, 0666)
-	oldFd, err := os.Open(h.knownHostsPath)
-	if err != nil {
-		panic(err)
-	}
-	defer oldFd.Close()
-
-	scanner := bufio.NewScanner(oldFd)
-
-	// Now, append all still valid old entries to the new host file
-	for scanner.Scan() {
-		line := scanner.Text()
-		address := strings.SplitN(line, " ", 2)[0]
-
-		if _, ok := addresses[address]; !ok {
-			newFd.WriteString(fmt.Sprintf("%s\n", line))
-		}
-	}
-
-	// Now, replace old known hosts file
-	if err := os.Rename(tmpKnownHostsPath, h.knownHostsPath); err != nil {
-		panic(err)
-	}
-}
-
-func (h *HostKeyCallback) dontTrustHosts(hosts []unknownHost) {
-	for _, unknown := range hosts {
-		unknown.responseCh <- dontTrustHost
-	}
-}
-
-// Untrusted returns true if the host is not trusted. False otherwise.
-func (h *HostKeyCallback) Untrusted(server string) bool {
-	h.mutex.Lock()
-	defer h.mutex.Unlock()
-	_, ok := h.untrustedHosts[server]
-
-	return ok
+type HostKeyCallback interface {
+	Wrap() ssh.HostKeyCallback
+	Untrusted(server string) bool
+	PromptAddHosts(ctx context.Context)
 }