Revert "ssh: add support for banners"
This reverts commit ed5229da99e3a6df35c756cd64b6982d19505d86.
Reason for revert: missing language tag in banner message breaks auth against other implementations.
Change-Id: I18ac5b3fe3b4693688b82ff4b0db02dab739c45b
Reviewed-on: https://go-review.googlesource.com/72381
Reviewed-by: Han-Wen Nienhuys <hanwen@google.com>
Run-TryBot: Han-Wen Nienhuys <hanwen@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/ssh/client.go b/ssh/client.go
index 6fd1994..a7e3263 100644
--- a/ssh/client.go
+++ b/ssh/client.go
@@ -9,7 +9,6 @@
"errors"
"fmt"
"net"
- "os"
"sync"
"time"
)
@@ -188,10 +187,6 @@
// net.Conn underlying the the SSH connection.
type HostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error
-// BannerCallback is the function type used for treat the banner sent by
-// the server. A BannerCallback receives the message sent by the remote server.
-type BannerCallback func(message string) error
-
// A ClientConfig structure is used to configure a Client. It must not be
// modified after having been passed to an SSH function.
type ClientConfig struct {
@@ -214,12 +209,6 @@
// FixedHostKey can be used for simplistic host key checks.
HostKeyCallback HostKeyCallback
- // BannerCallback is called during the SSH dance to display a custom
- // server's message. The client configuration can supply this callback to
- // handle it as wished. The function BannerDisplayStderr can be used for
- // simplistic display on Stderr.
- BannerCallback BannerCallback
-
// ClientVersion contains the version identification string that will
// be used for the connection. If empty, a reasonable default is used.
ClientVersion string
@@ -266,13 +255,3 @@
hk := &fixedHostKey{key}
return hk.check
}
-
-// BannerDisplayStderr returns a function that can be used for
-// ClientConfig.BannerCallback to display banners on os.Stderr.
-func BannerDisplayStderr() BannerCallback {
- return func(banner string) error {
- _, err := os.Stderr.WriteString(banner)
-
- return err
- }
-}
diff --git a/ssh/client_auth.go b/ssh/client_auth.go
index a1252cb..3acd8d4 100644
--- a/ssh/client_auth.go
+++ b/ssh/client_auth.go
@@ -283,9 +283,7 @@
}
switch packet[0] {
case msgUserAuthBanner:
- if err := handleBannerResponse(c, packet); err != nil {
- return false, err
- }
+ // TODO(gpaul): add callback to present the banner to the user
case msgUserAuthPubKeyOk:
var msg userAuthPubKeyOkMsg
if err := Unmarshal(packet, &msg); err != nil {
@@ -327,9 +325,7 @@
switch packet[0] {
case msgUserAuthBanner:
- if err := handleBannerResponse(c, packet); err != nil {
- return false, nil, err
- }
+ // TODO: add callback to present the banner to the user
case msgUserAuthFailure:
var msg userAuthFailureMsg
if err := Unmarshal(packet, &msg); err != nil {
@@ -344,24 +340,6 @@
}
}
-func handleBannerResponse(c packetConn, packet []byte) error {
- var msg userAuthBannerMsg
- if err := Unmarshal(packet, &msg); err != nil {
- return err
- }
-
- transport, ok := c.(*handshakeTransport)
- if !ok {
- return nil
- }
-
- if transport.bannerCallback != nil {
- return transport.bannerCallback(msg.Message)
- }
-
- return nil
-}
-
// KeyboardInteractiveChallenge should print questions, optionally
// disabling echoing (e.g. for passwords), and return all the answers.
// Challenge may be called multiple times in a single session. After
@@ -407,9 +385,7 @@
// like handleAuthResponse, but with less options.
switch packet[0] {
case msgUserAuthBanner:
- if err := handleBannerResponse(c, packet); err != nil {
- return false, nil, err
- }
+ // TODO: Print banners during userauth.
continue
case msgUserAuthInfoRequest:
// OK
diff --git a/ssh/client_test.go b/ssh/client_test.go
index f751eb6..ccf5607 100644
--- a/ssh/client_test.go
+++ b/ssh/client_test.go
@@ -79,40 +79,3 @@
}
}
}
-func TestBannerCallback(t *testing.T) {
- c1, c2, err := netPipe()
- if err != nil {
- t.Fatalf("netPipe: %v", err)
- }
- defer c1.Close()
- defer c2.Close()
-
- serverConf := &ServerConfig{
- NoClientAuth: true,
- BannerCallback: func(conn ConnMetadata) string {
- return "Hello World"
- },
- }
- serverConf.AddHostKey(testSigners["rsa"])
- go NewServerConn(c1, serverConf)
-
- var receivedBanner string
- clientConf := ClientConfig{
- User: "user",
- HostKeyCallback: InsecureIgnoreHostKey(),
- BannerCallback: func(message string) error {
- receivedBanner = message
- return nil
- },
- }
-
- _, _, _, err = NewClientConn(c2, "", &clientConf)
- if err != nil {
- t.Fatal(err)
- }
-
- expected := "Hello World"
- if receivedBanner != expected {
- t.Fatalf("got %s; want %s", receivedBanner, expected)
- }
-}
diff --git a/ssh/handshake.go b/ssh/handshake.go
index 4f7912e..932ce83 100644
--- a/ssh/handshake.go
+++ b/ssh/handshake.go
@@ -78,11 +78,6 @@
dialAddress string
remoteAddr net.Addr
- // bannerCallback is non-empty if we are the client and it has been set in
- // ClientConfig. In that case it is called during the user authentication
- // dance to handle a custom server's message.
- bannerCallback BannerCallback
-
// Algorithms agreed in the last key exchange.
algorithms *algorithms
@@ -125,7 +120,6 @@
t.dialAddress = dialAddr
t.remoteAddr = addr
t.hostKeyCallback = config.HostKeyCallback
- t.bannerCallback = config.BannerCallback
if config.HostKeyAlgorithms != nil {
t.hostKeyAlgorithms = config.HostKeyAlgorithms
} else {
diff --git a/ssh/messages.go b/ssh/messages.go
index 92f3810..e6ecd3a 100644
--- a/ssh/messages.go
+++ b/ssh/messages.go
@@ -23,6 +23,10 @@
msgUnimplemented = 3
msgDebug = 4
msgNewKeys = 21
+
+ // Standard authentication messages
+ msgUserAuthSuccess = 52
+ msgUserAuthBanner = 53
)
// SSH messages:
@@ -133,16 +137,6 @@
PartialSuccess bool
}
-// See RFC 4252, section 5.1
-const msgUserAuthSuccess = 52
-
-// See RFC 4252, section 5.4
-const msgUserAuthBanner = 53
-
-type userAuthBannerMsg struct {
- Message string `sshtype:"53"`
-}
-
// See RFC 4256, section 3.2
const msgUserAuthInfoRequest = 60
const msgUserAuthInfoResponse = 61
diff --git a/ssh/server.go b/ssh/server.go
index 148d2cb..8a78b7c 100644
--- a/ssh/server.go
+++ b/ssh/server.go
@@ -95,10 +95,6 @@
// Note that RFC 4253 section 4.2 requires that this string start with
// "SSH-2.0-".
ServerVersion string
-
- // BannerCallback, if present, is called and the return string is sent to
- // the client after key exchange completed but before authentication.
- BannerCallback func(conn ConnMetadata) string
}
// AddHostKey adds a private key as a host key. If an existing host
@@ -347,19 +343,6 @@
}
s.user = userAuthReq.User
-
- if authFailures == 0 && config.BannerCallback != nil {
- msg := config.BannerCallback(s)
- if msg != "" {
- bannerMsg := &userAuthBannerMsg{
- Message: msg,
- }
- if err := s.transport.writePacket(Marshal(bannerMsg)); err != nil {
- return nil, err
- }
- }
- }
-
perms = nil
authErr := errors.New("no auth passed yet")
