go.crypto/ssh: support OpenSSH keepalives
Fixes golang/go#4552.
R=minux.ma, agl
CC=golang-dev
https://golang.org/cl/6948059
diff --git a/ssh/client.go b/ssh/client.go
index a4daa24..e2a143e 100644
--- a/ssh/client.go
+++ b/ssh/client.go
@@ -309,6 +309,12 @@
// invalid window update
return
}
+ case *globalRequestMsg:
+ // This handles keepalive messages and matches
+ // the behaviour of OpenSSH.
+ if msg.WantReply {
+ c.writePacket(marshal(msgRequestFailure, globalRequestFailureMsg{}))
+ }
case *globalRequestSuccessMsg, *globalRequestFailureMsg:
c.globalRequest.response <- msg
case *disconnectMsg:
diff --git a/ssh/session.go b/ssh/session.go
index ac96d52..640d322 100644
--- a/ssh/session.go
+++ b/ssh/session.go
@@ -404,7 +404,13 @@
}
wm.lang = safeString(string(lang))
default:
- return fmt.Errorf("wait: unexpected channel request: %v", msg)
+ // This handles keepalives and matches
+ // OpenSSH's behaviour.
+ if msg.WantReply {
+ s.writePacket(marshal(msgChannelFailure, channelRequestFailureMsg{
+ PeersId: s.remoteId,
+ }))
+ }
}
default:
return fmt.Errorf("wait: unexpected packet %T received: %v", msg, msg)
diff --git a/ssh/session_test.go b/ssh/session_test.go
index 0c64ed2..218d002 100644
--- a/ssh/session_test.go
+++ b/ssh/session_test.go
@@ -498,6 +498,24 @@
}
}
+// Verify the client can handle a keepalive packet from the server.
+func TestClientHandlesKeepalives(t *testing.T) {
+ conn := dial(channelKeepaliveSender, t)
+ defer conn.Close()
+ session, err := conn.NewSession()
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer session.Close()
+ if err := session.Shell(); err != nil {
+ t.Fatalf("Unable to execute command: %v", err)
+ }
+ err = session.Wait()
+ if err != nil {
+ t.Fatalf("expected nil but got: %v", err)
+ }
+}
+
type exitStatusMsg struct {
PeersId uint32
Request string
@@ -687,3 +705,18 @@
}
return written, nil
}
+
+func channelKeepaliveSender(ch *serverChan, t *testing.T) {
+ defer ch.Close()
+ shell := newServerShell(ch, "> ")
+ readLine(shell, t)
+ msg := channelRequestMsg{
+ PeersId: ch.remoteId,
+ Request: "keepalive@openssh.com",
+ WantReply: true,
+ }
+ if err := ch.writePacket(marshal(msgChannelRequest, msg)); err != nil {
+ t.Errorf("unable to send channel keepalive request: %v", err)
+ }
+ sendStatus(0, ch, t)
+}
