Null pointer when authenticating as guest

[dkocher]

Attempting to authenticate as guest using AuthenticationContext.guest() results in an exception

Caused by: java.lang.NullPointerException
	at com.hierynomus.smbj.connection.SMBSessionBuilder.deriveKey(SMBSessionBuilder.java:324)
	at com.hierynomus.smbj.connection.SMBSessionBuilder.deriveKeys(SMBSessionBuilder.java:290)
	at com.hierynomus.smbj.connection.SMBSessionBuilder.setupSession(SMBSessionBuilder.java:174)
	at com.hierynomus.smbj.connection.SMBSessionBuilder.setupSession(SMBSessionBuilder.java:152)
	at com.hierynomus.smbj.connection.SMBSessionBuilder.establish(SMBSessionBuilder.java:119)
	at com.hierynomus.smbj.connection.Connection.authenticate(Connection.java:197)

The server is running SMB_3_1_1 (Windows Server 2022)

[hierynomus]

@dkocher Which version? I fixed a similar bug for anonymous authentication in v0.12.2, and I thought I had checked guest then also.

[dkocher]

@dkocher Which version? I fixed a similar bug for anonymous authentication in v0.12.2, and I thought I had checked guest then also.

Running 0.12.2.

[hierynomus]

@dkocher Which authenticator are you using?

[dkocher]

@dkocher Which authenticator are you using?

This is using NtlmAuthenticator.

[karthik-119]

Even, I'm facing the same Nullpointer exception when trying with anonymous login:

java.lang.NullPointerException
  at com.hierynomus.smbj.connection.SMBSessionBuilder.deriveKey(SMBSessionBuilder.java:324)
  at com.hierynomus.smbj.connection.SMBSessionBuilder.deriveKeys(SMBSessionBuilder.java:290)
  at com.hierynomus.smbj.connection.SMBSessionBuilder.setupSession(SMBSessionBuilder.java:174)
  at com.hierynomus.smbj.connection.SMBSessionBuilder.setupSession(SMBSessionBuilder.java:152)
  at com.hierynomus.smbj.connection.SMBSessionBuilder.establish(SMBSessionBuilder.java:119)
  at com.hierynomus.smbj.connection.Connection.authenticate(Connection.java:202)

It is happening after upgrade to smbj library 0.12.2 and my target server Windows 11 (protocol: SMB_3_1_1), I've tried to allow insecure guest logons as well in my Local group policy editor.

Not sure if this is relevant but found this while debugging that this can be the cause:

if (!ctx.authContext.isAnonymous() && !ctx.authContext.isGuest()) {
                context.setSessionKey(new SecretKeySpec(ctx.sessionKey, HMAC_SHA256_ALGORITHM));
 }

session key is set to context when it is neither anonymous nor guest, meaning only for user context, thus later in the derivekeys, this ended up in NullPointer.

Is there any update on the issue, whether if it's server configuration issue or bug in the actual code?

[dkocher]

@karthik-119 points out this may be a regression of 4633709.

[hierynomus]

@dkocher @karthik-119 Can you try with the fix from #800?

[bubbleguuum]

I tested and:

• I get the crash in first post with published 0.12.2 (expected)
• I do not get the crash using current git smbj as of the date of this post without Set sessionKey whenever we have it from authentication (Fixes #792) #800 applied

So that issue has already been fixed by a commit post v0.12.2 it seems.

[hierynomus]

@bubbleguuum Now that's even weirder, as Git doesn't show any change which could have anything to do with that on the current master branch 🤔

[bubbleguuum]

Yes please disregard, I did my testing wrong (was actually using v0.11.1 instead of git master!).
Will do it again properly with the PR applied.

[bubbleguuum]

Still crashing using master git + the 1 line PR.
Double checked that everything is correct this time, with even a logged "LALA" line just before the if (ctx.sessionKey != null) { line change:

smb: resolved FOOBAR -> 192.168.1.157
        PacketEncryptor  I  Initialized PacketEncryptor with Cipher << AES_128_CCM >>
             Connection  I  Successfully connected to: 192.168.1.157
           SMBShareInfo  I  smb: \\FOOBAR\: NegotiatedProtocol{dialect=SMB_3_0_2, maxTransactSize=8388608, maxReadSize=8388608, maxWriteSize=8388608}
      SMBSessionBuilder  I  LALA
           SMBShareInfo  W  java.lang.NullPointerException: Attempt to invoke interface method 'byte[] javax.crypto.SecretKey.getEncoded()' on a null object reference
                         W      at com.hierynomus.smbj.connection.SMBSessionBuilder.deriveKey(SMBSessionBuilder.java:326)
                         W      at com.hierynomus.smbj.connection.SMBSessionBuilder.deriveKeys(SMBSessionBuilder.java:294)
                         W      at com.hierynomus.smbj.connection.SMBSessionBuilder.setupSession(SMBSessionBuilder.java:176)
                         W      at com.hierynomus.smbj.connection.SMBSessionBuilder.setupSession(SMBSessionBuilder.java:152)
                         W      at com.hierynomus.smbj.connection.SMBSessionBuilder.establish(SMBSessionBuilder.java:119)
                         W      at com.hierynomus.smbj.connection.Connection.authenticate(Connection.java:202)
                      ...

[karthik-119]

@dkocher @karthik-119 Can you try with the fix from #800?

@hierynomus , let me try to verify the fix.