x/crypto/ssh: "ssh: handshake failed: EOF" with 3des-cbc #32075

eikenb · 2019-05-16T03:46:08Z

What version of Go are you using (`go version`)?

$ go version
go version go1.12.5 linux/amd64

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (`go env`)?

go env Output

$ go env
GOARCH="amd64"
GOBIN="/home/jae/.local/bin"
GOCACHE="/home/jae/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/jae/projects/go/golib:/home/jae/projects/go/gotools:/home/jae/projects/go/mylib"
GOPROXY=""
GORACE=""
GOROOT="/home/jae/projects/go/goroot"
GOTMPDIR=""
GOTOOLDIR="/home/jae/projects/go/goroot/pkg/tool/linux_amd64"
GCCGO="/usr/bin/gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/jae/notes/developement/programming/go/examples/misc-tests/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build225295978=/tmp/go-build -gno-record-gcc-switches"

What did you do?

I help maintain the github.com/pkg/sftp library and am helping a user with an ssh issue. They have an SFTP server that only supports some older ciphers, like 3des-cbc and they can't connect successfully. I've tried to simplify and reproduce their issue with some success. I've configured my local openssh server to only accept that cipher, with Ciphers 3des-cbc in the sshd_config and was able to connect to it with the openssh client with ssh -c 3des-cbc localhost. If I don't specify -c 3des-cbc on the command line it won't connect with a negotiation error. So everything seems good on that side.

I then try to connect with a simple program using x/crypto/ssh set to use that same cipher and get the error ssh: handshake failed: EOF and the openssh server spits out the following in the log.

May 15 20:41:26 XXX sshd[12686]: Bad packet length 1474871687. [preauth]
May 15 20:41:26 XXX sshd[12686]: ssh_dispatch_run_fatal: Connection from 127.0.0.1 port 53234: Connection corrupted [preauth]

My simple program to reproduce is..

package main

import (
	"fmt"
	"net"
	"os"

	"golang.org/x/crypto/ssh"
	"golang.org/x/crypto/ssh/agent"
)

func main() {
	sshagent, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
	if err != nil {
		panic(err)
	}
	signer := ssh.PublicKeysCallback(agent.NewClient(sshagent).Signers)

	sshConfig := &ssh.ClientConfig{
		User:            os.ExpandEnv("$USER"),
		Auth:            []ssh.AuthMethod{signer},
		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
	}
	sshConfig.SetDefaults()
	sshConfig.Ciphers = []string{"3des-cbc"}

	_, err = ssh.Dial("tcp", "localhost:22", sshConfig)
	fmt.Printf("%v\n", err)
}

What did you expect to see?

No error and have it connect.

What did you see instead?

ssh: handshake failed: EOF

Thanks.

The text was updated successfully, but these errors were encountered:

FiloSottile · 2019-05-17T14:57:37Z

/cc @hanwen

manhquyet-nguyen · 2019-06-12T05:51:53Z

Any update on this issue? I got the same problem.
Connect from terminal is OK but failed via ssh.
The server ssh version is SSH-2.0-OpenSSH_6.2

hanwen · 2019-06-17T13:53:00Z

I've been on hoidays. I'll try to have a look one of these weeks.

manhquyet-nguyen · 2019-06-20T08:04:01Z

I've debugged.
Server accept: [aes128-ctr aes192-ctr aes256-ctr arcfour256 arcfour128 aes128-gcm@openssh.com aes256-gcm@openssh.com aes128-cbc 3des-cbc blowfish-cbc cast128-cbc aes192-cbc aes256-cbc arcfour rijndael-cbc@lysator.liu.se]
Working algorithm are: [aes128-ctr aes192-ctr aes256-ctr arcfour256 arcfour128 arcfour]
The other cause the ssh failed with EOF error

eikenb · 2019-12-30T20:33:14Z

@hanwen

I had another user file a bug about this. I don't want to nag as I know how hard it can be to find time to work on things but I just wanted to ping the issue again to help it stay on the radar. Thanks.

poojashete · 2021-05-31T16:58:08Z

I am facing similar issue where I cant connect to docker IP and getting ssh: handshake failed EOF error.

Copying snippet of my code

`
func scp() (bool, error) {

    var hostKey ssh.PublicKey
    if err != nil {
            fmt.Println("Upload: Failed to Connect")
            return isUploaded, err
    }
    // Define the Client Config as :
    config := &ssh.ClientConfig{
            User: "root",
            Auth: []ssh.AuthMethod{
                    ssh.PublicKeys(key),
            },
            Config: ssh.Config{
                     KeyExchanges: []string{"diffie-hellman-group-exchange-sha256",
                                            "curve25519-sha256@libssh.org ecdh-sha2-nistp256",
                                            "ecdh-sha2-nistp384 ecdh-sha2-nistp521",
                                            "diffie-hellman-group14-sha1",
                                            "diffie-hellman-group1-sha1",
                                            "aes128-ctr",
                                            "aes192-ctr",
                                            "aes256-ctr",
                                            "arcfour256",
                                            "arcfour128",
                                            "arcfour",
                            },
            },
            HostKeyCallback: ssh.FixedHostKey(hostKey),
            }
     fmt.Println("Dialing .... ")
    client, err := ssh.Dial("tcp", ip1+":8080", config)
    if err != nil {
            fmt.Println("Failed to dial IP1: " + err.Error())
    }
    defer client.Close()

}`

Tried with and without default KeyExchanges.

Getting below error

Failed to dial IP1: ssh: handshake failed: EOF

4a6f656c · 2022-06-18T18:40:53Z

@eikenb the cause of this is most likely Encrypt-then-MAC (EtM) mode - 84bacda added support for hmac-sha2-256-etm@openssh.com, however only implemented it for stream ciphers (arcfour*) and not for CBC block ciphers (aes128-cbc and 3des-cbc). This means that the SSH client will advertise support for EtM, the SSH server will select a CBC cipher with EtM, then the client fails to handle the resulting packets correctly (these days it will likely appear in the form of an invalid packet length error, rather than EOF).

Until this is fixed, the workaround would be to specify one or more MACs, excluding EtM (e.g. hmac-sha2-256).

mhkyle · 2023-08-03T08:14:42Z

same issues happened, when try to use ssh key to execute some commands on the linux nodes by use net/dial.go to do it and

ssh: handshake failed: EOF

Most wired thing is that for some times it failed, while after reconciling and retry, it can work after retrying.

cserken · 2023-10-18T07:58:42Z

same issues happened, when try to use ssh key to execute some commands on the linux nodes by use net/dial.go to do it and
ssh: handshake failed: EOF
Most wired thing is that for some times it failed, while after reconciling and retry, it can work after retrying.

I have got the same issues and also work after retry.
By the way, any updates or fixed plan about this issue? @4a6f656c

gopherbot added this to the Unreleased milestone May 16, 2019

eikenb mentioned this issue May 16, 2019

Error“internal inconsistency” in downloading file from special sftp server whish is old cipher pkg/sftp#287

Open

FiloSottile added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label May 17, 2019

eikenb mentioned this issue Dec 30, 2019

internal inconsistency pkg/sftp#327

Closed

drognisep mentioned this issue Jul 16, 2020

Unable to connect to Ubuntu 16.04 drognisep/sshtail#2

Closed

oldthreefeng mentioned this issue Sep 3, 2020

缺陷: 在拷贝文件时出现ssh: handshake failed labring/sealos#444

Closed

smallinsky mentioned this issue Jan 12, 2022

After enabling TLS Routing, unable to join nodes or login vis tsh gravitational/teleport#9745

Closed

MrColdboot mentioned this issue Jan 2, 2023

Possible regression: Connection to libvirt via SSH fails with provider version 0.6.14 dmacvicar/terraform-provider-libvirt#939

Open

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x/crypto/ssh: "ssh: handshake failed: EOF" with 3des-cbc #32075

x/crypto/ssh: "ssh: handshake failed: EOF" with 3des-cbc #32075

eikenb commented May 16, 2019

FiloSottile commented May 17, 2019

manhquyet-nguyen commented Jun 12, 2019

hanwen commented Jun 17, 2019

manhquyet-nguyen commented Jun 20, 2019

eikenb commented Dec 30, 2019

poojashete commented May 31, 2021 •

edited

4a6f656c commented Jun 18, 2022

mhkyle commented Aug 3, 2023 •

edited

cserken commented Oct 18, 2023

x/crypto/ssh: "ssh: handshake failed: EOF" with 3des-cbc #32075

x/crypto/ssh: "ssh: handshake failed: EOF" with 3des-cbc #32075

Comments

eikenb commented May 16, 2019

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

What did you do?

What did you expect to see?

What did you see instead?

FiloSottile commented May 17, 2019

manhquyet-nguyen commented Jun 12, 2019

hanwen commented Jun 17, 2019

manhquyet-nguyen commented Jun 20, 2019

eikenb commented Dec 30, 2019

poojashete commented May 31, 2021 • edited

4a6f656c commented Jun 18, 2022

mhkyle commented Aug 3, 2023 • edited

cserken commented Oct 18, 2023

What version of Go are you using (`go version`)?

What operating system and processor architecture are you using (`go env`)?

poojashete commented May 31, 2021 •

edited

mhkyle commented Aug 3, 2023 •

edited