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NullPointerException using OpenSSH RSA public key #484

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talaieru opened this issue Jan 12, 2019 · 4 comments · Fixed by #485
Closed

NullPointerException using OpenSSH RSA public key #484

talaieru opened this issue Jan 12, 2019 · 4 comments · Fixed by #485

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@talaieru
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When the authentication key (in ~/.ssh/id_rsa) is in OpenSSH format, then the OpenSSHKeyV1KeyFile key provider is used. Invoking SshClient.authPublicKey with such key results in a NullPointerException because the PasswordFinder pwdf is null. As far as I can see OpenSSHKeyV1KeyFile cannot handle correctly the case where no password is provided.

The following Java code can be used to reproduce the issue:

import java.nio.file.Path;
import java.nio.file.Paths;

import net.schmizz.sshj.SSHClient;
import net.schmizz.sshj.xfer.FileSystemFile;

public class BugWithOpenSshKey {
    public static void main(String[] args) throws Exception {
        Path parentPath = Paths.get("/tmp/certs");

        SSHClient ssh = new SSHClient();
        ssh.addHostKeyVerifier((hostname, port, key) -> true);
        ssh.addAlgorithmsVerifier(algorithms -> true);

        try {
            ssh.connect("remoteHost");
            ssh.authPublickey("root");
            ssh.newSCPFileTransfer().download("/var/opt/certs/nevisfido-metadata-keystore.p12",
                    new FileSystemFile(parentPath.toString()));
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            ssh.disconnect();
        }
    }
}

The output is:

15:09:43.601 [main] INFO net.schmizz.sshj.transport.random.BouncyCastleRandom - Generating random seed from SecureRandom.
15:09:43.605 [main] DEBUG net.schmizz.sshj.transport.random.BouncyCastleRandom - Creating random seed took 0 ms
15:09:43.659 [main] DEBUG net.schmizz.sshj.DefaultConfig - Available cipher factories: [aes128-cbc, aes128-ctr, aes192-cbc, aes192-ctr, aes256-cbc, aes256-ctr, blowfish-cbc, blowfish-ctr, cast128-cbc, cast128-ctr, idea-cbc, idea-ctr, serpent128-cbc, serpent128-ctr, serpent192-cbc, serpent192-ctr, serpent256-cbc, serpent256-ctr, 3des-cbc, 3des-ctr, twofish128-cbc, twofish128-ctr, twofish192-cbc, twofish192-ctr, twofish256-cbc, twofish256-ctr, twofish-cbc, arcfour, arcfour128, arcfour256]
15:09:43.692 [main] INFO net.schmizz.sshj.transport.TransportImpl - Client identity string: SSH-2.0-SSHJ_0.26.0
15:09:43.705 [main] INFO net.schmizz.sshj.transport.TransportImpl - Server identity string: SSH-2.0-OpenSSH_7.4
15:09:43.705 [main] DEBUG net.schmizz.concurrent.Promise - Setting <<kex done>> to `null`
15:09:43.705 [main] DEBUG net.schmizz.sshj.transport.KeyExchanger - Sending SSH_MSG_KEXINIT
15:09:43.712 [reader] DEBUG net.schmizz.sshj.transport.KeyExchanger - Received SSH_MSG_KEXINIT
15:09:43.713 [reader] DEBUG net.schmizz.concurrent.Promise - Awaiting <<kexinit sent>>
15:09:43.713 [main] DEBUG net.schmizz.concurrent.Promise - Setting <<kexinit sent>> to `SOME`
15:09:43.713 [main] DEBUG net.schmizz.concurrent.Promise - Awaiting <<kex done>>
15:09:43.714 [reader] DEBUG net.schmizz.sshj.transport.KeyExchanger - Negotiated algorithms: [ kex=curve25519-sha256@libssh.org; sig=ecdsa-sha2-nistp256; c2sCipher=aes128-cbc; s2cCipher=aes128-cbc; c2sMAC=hmac-sha1; s2cMAC=hmac-sha1; c2sComp=none; s2cComp=none ]
15:09:43.714 [reader] DEBUG net.schmizz.sshj.transport.KeyExchanger - Trying to verify algorithms with BugWithOpenSshKey$$Lambda$3/516934601@11cd711
15:09:43.775 [reader] DEBUG net.schmizz.sshj.transport.kex.Curve25519SHA256 - Sending SSH_MSG_KEXDH_INIT
15:09:43.787 [reader] DEBUG net.schmizz.sshj.transport.KeyExchanger - Received kex followup data
15:09:43.787 [reader] DEBUG net.schmizz.sshj.transport.kex.Curve25519SHA256 - Received SSH_MSG_KEXDH_REPLY
15:09:43.787 [reader] DEBUG net.schmizz.sshj.common.ECDSAVariationsAdapter - Key algo: ecdsa-sha2-nistp256, Key curve: nistp256, Key Len: 65, 0x04: 4
x: [-36, -56, -36, -60, 95, 80, 98, 117, 80, 46, 58, 121, 127, -112, -64, 0, -89, 67, 87, 122, 75, -86, -20, 1, -64, -108, -121, 23, -33, 87, 102, 16]
y: [-56, -34, -83, 25, 28, 39, 114, -24, 0, 105, -62, -13, -115, -58, 88, 126, 56, 86, -31, -48, 78, -114, 29, 8, -83, 5, 77, -27, -25, -8, -60, 18]
15:09:43.927 [reader] DEBUG net.schmizz.sshj.transport.KeyExchanger - Trying to verify host key with BugWithOpenSshKey$$Lambda$2/1386020581@32b1c013
15:09:43.928 [reader] DEBUG net.schmizz.sshj.transport.KeyExchanger - Sending SSH_MSG_NEWKEYS
15:09:43.930 [reader] DEBUG net.schmizz.sshj.transport.KeyExchanger - Received SSH_MSG_NEWKEYS
15:09:43.933 [reader] DEBUG net.schmizz.concurrent.Promise - Setting <<kexinit sent>> to `null`
15:09:43.933 [reader] DEBUG net.schmizz.concurrent.Promise - Setting <<kex done>> to `SOME`
15:09:43.934 [main] DEBUG net.schmizz.sshj.SSHClient - Key exchange took 0.229 seconds
15:09:43.934 [main] DEBUG net.schmizz.sshj.SSHClient - Attempting to load key from: /Users/josu/.ssh/id_rsa
15:09:43.936 [main] DEBUG net.schmizz.sshj.SSHClient - Attempting to load key from: /Users/josu/.ssh/id_dsa
15:09:43.936 [main] INFO net.schmizz.sshj.SSHClient - Could not load keys from /Users/josu/.ssh/id_dsa due to: /Users/josu/.ssh/id_dsa (No such file or directory)
15:09:43.937 [main] DEBUG net.schmizz.sshj.SSHClient - Attempting to load key from: /Users/josu/.ssh/id_ed25519
15:09:43.937 [main] INFO net.schmizz.sshj.SSHClient - Could not load keys from /Users/josu/.ssh/id_ed25519 due to: /Users/josu/.ssh/id_ed25519 (No such file or directory)
15:09:43.937 [main] DEBUG net.schmizz.sshj.SSHClient - Attempting to load key from: /Users/josu/.ssh/id_ecdsa
15:09:43.937 [main] INFO net.schmizz.sshj.SSHClient - Could not load keys from /Users/josu/.ssh/id_ecdsa due to: /Users/josu/.ssh/id_ecdsa (No such file or directory)
15:09:43.938 [main] DEBUG net.schmizz.concurrent.Promise - Setting <<service accept>> to `null`
15:09:43.938 [main] DEBUG net.schmizz.sshj.transport.TransportImpl - Sending SSH_MSG_SERVICE_REQUEST for ssh-userauth
15:09:43.938 [main] DEBUG net.schmizz.concurrent.Promise - Awaiting <<service accept>>
15:09:43.978 [reader] DEBUG net.schmizz.concurrent.Promise - Setting <<service accept>> to `SOME`
15:09:43.979 [main] DEBUG net.schmizz.sshj.transport.TransportImpl - Setting active service to ssh-userauth
15:09:43.979 [main] DEBUG net.schmizz.concurrent.Promise - Setting <<authenticated>> to `null`
15:09:43.979 [main] DEBUG net.schmizz.sshj.userauth.UserAuthImpl - Trying `publickey` auth...
15:09:43.979 [main] DEBUG net.schmizz.sshj.userauth.method.AuthPublickey - Attempting authentication using com.hierynomus.sshj.userauth.keyprovider.OpenSSHKeyV1KeyFile@22d9c961
15:09:43.983 [main] INFO com.hierynomus.sshj.userauth.keyprovider.OpenSSHKeyV1KeyFile - Keypair is encrypted with: aes256-ctr, bcrypt, [B@29f0c4f2
java.lang.NullPointerException
	at com.hierynomus.sshj.userauth.keyprovider.OpenSSHKeyV1KeyFile.initializeCipher(OpenSSHKeyV1KeyFile.java:127)
	at com.hierynomus.sshj.userauth.keyprovider.OpenSSHKeyV1KeyFile.decryptBuffer(OpenSSHKeyV1KeyFile.java:118)
	at com.hierynomus.sshj.userauth.keyprovider.OpenSSHKeyV1KeyFile.readDecodedKeyPair(OpenSSHKeyV1KeyFile.java:110)
	at com.hierynomus.sshj.userauth.keyprovider.OpenSSHKeyV1KeyFile.readKeyPair(OpenSSHKeyV1KeyFile.java:79)
	at net.schmizz.sshj.userauth.keyprovider.BaseFileKeyProvider.getPublic(BaseFileKeyProvider.java:81)
	at net.schmizz.sshj.userauth.method.KeyedAuthMethod.putPubKey(KeyedAuthMethod.java:44)
	at net.schmizz.sshj.userauth.method.AuthPublickey.buildReq(AuthPublickey.java:62)
	at net.schmizz.sshj.userauth.method.AuthPublickey.buildReq(AuthPublickey.java:81)
	at net.schmizz.sshj.userauth.method.AbstractAuthMethod.request(AbstractAuthMethod.java:68)
	at net.schmizz.sshj.userauth.UserAuthImpl.authenticate(UserAuthImpl.java:72)
	at net.schmizz.sshj.SSHClient.auth(SSHClient.java:225)
	at net.schmizz.sshj.SSHClient.authPublickey(SSHClient.java:346)
	at net.schmizz.sshj.SSHClient.authPublickey(SSHClient.java:395)
	at net.schmizz.sshj.SSHClient.authPublickey(SSHClient.java:325)
	at BugWithOpenSshKey.main(BugWithOpenSshKey.java:17)
15:09:43.985 [main] INFO net.schmizz.sshj.transport.TransportImpl - Disconnected - BY_APPLICATION
15:09:43.985 [main] DEBUG net.schmizz.sshj.userauth.UserAuthImpl - Notified of net.schmizz.sshj.transport.TransportException: [BY_APPLICATION] Disconnected
15:09:43.985 [main] DEBUG net.schmizz.sshj.transport.TransportImpl - Sending SSH_MSG_DISCONNECT: reason=[BY_APPLICATION], msg=[]
15:09:43.986 [main] DEBUG net.schmizz.concurrent.Promise - Setting <<transport close>> to `SOME`
15:09:43.986 [reader] DEBUG net.schmizz.sshj.transport.Reader - Stopping

This has been reproduced using Mac OS 10.14.2. An excerpt of my id_rsa contents:

cat ~/.ssh/id_rsa
-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAACmFlczI1Ni1jdHIAAAAGYmNyeXB0AAAAGAAAABD3PhhEIe
@hierynomus
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Owner

Is your private key protected by a passphrase? SSHJ tries to decrypt the key. If it is not, I'd like to know the exact command to generate such a key.

I agree that an NPE is bad, but before deciding on the solution I'd need to know the above.

@talaieru
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talaieru commented Jan 14, 2019 via email

@hierynomus
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Owner

Indeed, thanks for the reply. I also figured out that the RSA keytype in the new format does not work (yet). Will fix the following things:

  • Support RSA in OpenSSHv1 keyfile format
  • Check for set PasswordFinder in case of encrypted keyfile (prevent NPE)
  • Add an SSHClient.authPublicKey(String username, PasswordFinder pwdf)

Currently you could do it using the client.authPublicKey("root", client.loadKeys("/Users/josu/.ssh/id_rsa"));

@dkocher
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dkocher commented Jan 16, 2019

Duplicate for #276.

@hierynomus hierynomus mentioned this issue Jan 16, 2019
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Add support for other keytypes to openssh-key-v1 keyfiles hierynomus/sshj
3 participants
@dkocher @hierynomus @talaieru