diff options
Diffstat (limited to 'handshake/handshake.go')
| -rw-r--r-- | handshake/handshake.go | 174 |
1 files changed, 0 insertions, 174 deletions
diff --git a/handshake/handshake.go b/handshake/handshake.go index 880e907..e5e3c37 100644 --- a/handshake/handshake.go +++ b/handshake/handshake.go @@ -1,21 +1,10 @@ package handshake import ( - "bufio" "context" - "errors" - "fmt" "golang.org/x/sync/errgroup" - "io" - "net" - "net/netip" - "os" - "slices" - "strings" "time" - "git.samanthony.xyz/hose/hosts" - "git.samanthony.xyz/hose/key" "git.samanthony.xyz/hose/util" ) @@ -27,15 +16,6 @@ const ( retryInterval = 500 * time.Millisecond ) -var errHostKey = errors.New("host key verification failed") - -type keyType string - -const ( - boxPublicKey keyType = "Public encryption key" - sigPublicKey = "Public signature verification key" -) - // Handshake exchanges public keys with a remote host. // The user is asked to verify the received keys before they are saved in the known hosts file. func Handshake(rhost string) error { @@ -66,157 +46,3 @@ func Handshake(rhost string) error { return nil } } - -// send sends the local public box (encryption) key to a remote host. -func send(rhost string) error { - pubBoxkey, err := key.LoadBoxPublicKey() - if err != nil { - return err - } - - pubSigKey, err := key.LoadSigPublicKey() - if err != nil { - return err - } - - raddr := net.JoinHostPort(rhost, port) - util.Logf("connecting to %s...", raddr) - conn, err := dialWithTimeout(network, raddr, timeout) - if err != nil { - return err - } - defer conn.Close() - util.Logf("connected to %s", raddr) - - if _, err := conn.Write(pubBoxkey[:]); err != nil { - return err - } - if _, err := conn.Write(pubSigKey[:]); err != nil { - return err - } - - util.Logf("sent public keys to %s", rhost) - return nil -} - -func dialWithTimeout(network, address string, timeout time.Duration) (net.Conn, error) { - ctx, cancel := context.WithTimeout(context.Background(), timeout) - defer cancel() - for { - select { - case <-ctx.Done(): // timeout. - return nil, fmt.Errorf("dial %s %s: connection refused", network, address) - default: - } - conn, err := net.Dial(network, address) - if err == nil { - return conn, nil - } - time.Sleep(retryInterval) - } -} - -// receive receives the public keys of a remote host. -// The user is asked to verify the keys before they are saved to the known hosts file. -func receive(rhost string) error { - // Listen for connection. - laddr := net.JoinHostPort("", port) - ln, err := net.Listen(network, laddr) - if err != nil { - return err - } - defer ln.Close() - util.Logf("listening on %s", laddr) - - conn, err := ln.Accept() - if err != nil { - return err - } - defer conn.Close() - util.Logf("accepted connection from %s", conn.RemoteAddr()) - - // Receive public box (encryption) key from remote host. - var rBoxPubKey key.BoxPublicKey - _, err = io.ReadFull(conn, rBoxPubKey[:]) - if err != nil { - return err - } - util.Logf("received public encryption key from %s", conn.RemoteAddr()) - - // Receive public signature verification key from remote host. - var rSigPubKey key.SigPublicKey - _, err = io.ReadFull(conn, rSigPubKey[:]) - if err != nil { - return err - } - util.Logf("receive public signature verification key from %s", conn.RemoteAddr()) - - // Ask user to verify the keys. - host, _, err := net.SplitHostPort(conn.RemoteAddr().String()) - if err != nil { - return err - } - raddr, err := netip.ParseAddr(host) - if err != nil { - return err - } - // Verify box key. - ok, err := verifyKey(raddr, rBoxPubKey[:], boxPublicKey) - if err != nil { - return err - } - if !ok { // user rejected the key. - return errHostKey - } - // Verify signature verification key. - ok, err = verifyKey(raddr, rSigPubKey[:], sigPublicKey) - if err != nil { - return err - } - if !ok { // user rejected the key. - return errHostKey - } - - // Save in known hosts file. - return hosts.Add(hosts.Host{raddr, rBoxPubKey, rSigPubKey}) -} - -// verifyKey asks the user to verify a key received from a remote host. -// It returns true if the user accepts the key, or false if they don't, or a non-nil error. -func verifyKey(host netip.Addr, key []byte, kt keyType) (bool, error) { - // Ask host to verify the key. - util.Logf("%s key of host %q: %x\nIs this the correct key (yes/[no])?", - kt, host, key[:]) - response, err := scan([]string{"yes", "no", ""}) - if err != nil { - return false, err - } - switch response { - case "yes": - return true, nil - case "no": - return false, nil - case "": - return false, nil // default option - } - panic("unreachable") -} - -// scan reads from stdin until the user enters one of the valid responses. -func scan(responses []string) (string, error) { - scanner := bufio.NewScanner(os.Stdin) - scanner.Scan() - if err := scanner.Err(); err != nil { - return "", err - } - response := strings.TrimSpace(scanner.Text()) - for !slices.Contains(responses, response) { - util.Logf("Please enter one of %q", responses) - scanner.Scan() - if err := scanner.Err(); err != nil { - return "", err - } - response = strings.TrimSpace(scanner.Text()) - } - return response, nil -} |