Fix NTLMv2 hash when username contains non-ASCII characters

[cdelafuente-r7]

This fixes #55.

See the issue for details. After the fix:

❯ ruby examples/authenticate.rb 10.0.0.68 юзер 123456
SMB3 : (0x00000000) STATUS_SUCCESS: The operation completed successfully.
Netbios Name: MYWIN2016
Netbios Domain: TESTLAB
FQDN of the computer: mywin2016.testlab.local
FQDN of the domain: testlab.local
FQDN of the forest: testlab.local
Dialect: 0x0311
OS Version: 10.0.14393
SMB2 : (0x00000000) STATUS_SUCCESS: The operation completed successfully.
Netbios Name: MYWIN2016
Netbios Domain: TESTLAB
FQDN of the computer: mywin2016.testlab.local
FQDN of the domain: testlab.local
FQDN of the forest: testlab.local
Dialect: 0x0210
OS Version: 10.0.14393
SMB1 : (0x00000000) STATUS_SUCCESS: The operation completed successfully.
Native OS: Windows Server 2016 Standard 14393
Native LAN Manager: Windows Server 2016 Standard 6.3
Netbios Name: MYWIN2016
Netbios Domain: TESTLAB
FQDN of the computer: mywin2016.testlab.local
FQDN of the domain: testlab.local
FQDN of the forest: testlab.local
Dialect: NT LM 0.12
OS Version: 10.0.14393
SMB2 : (0x00000000) STATUS_SUCCESS: The operation completed successfully.
Netbios Name: MYWIN2016
Netbios Domain: TESTLAB
FQDN of the computer: mywin2016.testlab.local
FQDN of the domain: testlab.local
FQDN of the forest: testlab.local
Dialect: 0x0210
OS Version: 10.0.14393
SMB3 : (0x00000000) STATUS_SUCCESS: The operation completed successfully.
Netbios Name: MYWIN2016
Netbios Domain: TESTLAB
FQDN of the computer: mywin2016.testlab.local
FQDN of the domain: testlab.local
FQDN of the forest: testlab.local
Dialect: 0x0311
OS Version: 10.0.14393

[cdelafuente-r7]

I noticed there is still an encoding issue using some specific characters (e.g Hélène). It looks like the issue is due to how strings are encoded and concatenated in Net::NTLM::Message#serialize.

I added a fix and I wrote some specs to show the issue (added to spec/lib/net/ntlm/message/type3_spec.rb specs) in 11ef238.

  ...
  describe '#serialize' do
    context 'when the username contains non-ASCI characters' do
      let(:t3) {
        t2 = Net::NTLM::Message::Type2.new
        t2.response(
          {
            :user => 'Hélène',
            :password => '123456',
            :domain => ''
          },
          {
            :ntlmv2 => true,
            :workstation => 'testlab.local'
          }
        )
      }

      it 'serializes without error' do
        expect { t3.serialize }.not_to raise_error
      end
    end
  end
  ...

Before the fix

❯ rspec spec/lib/net/ntlm/message/type3_spec.rb -e 'when the username contains non-ASCI characters'
Run options: include {:full_description=>/when\ the\ username\ contains\ non\-ASCI\ characters/}

Net::NTLM::Message::Type3
  #serialize
    when the username contains non-ASCI characters
      serializes without error (FAILED - 1)

Failures:

  1) Net::NTLM::Message::Type3#serialize when the username contains non-ASCI characters serializes without error
     Failure/Error: expect { t3.serialize }.not_to raise_error

       expected no Exception, got #<Encoding::CompatibilityError: incompatible character encodings: ASCII-8BIT and UTF-8> with backtrace:
         # ./lib/net/ntlm/message.rb:90:in `join'
         # ./lib/net/ntlm/message.rb:90:in `serialize'
         # ./spec/lib/net/ntlm/message/type3_spec.rb:243:in `block (5 levels) in <top (required)>'
         # ./spec/lib/net/ntlm/message/type3_spec.rb:243:in `block (4 levels) in <top (required)>'
     # ./spec/lib/net/ntlm/message/type3_spec.rb:243:in `block (4 levels) in <top (required)>'

Finished in 0.02305 seconds (files took 0.1948 seconds to load)
1 example, 1 failure

Failed examples:

rspec ./spec/lib/net/ntlm/message/type3_spec.rb:242 # Net::NTLM::Message::Type3#serialize when the username contains non-ASCI characters serializes without error

After the fix

❯ rspec spec/lib/net/ntlm/message/type3_spec.rb -e 'when the username contains non-ASCI characters'
Run options: include {:full_description=>/when\ the\ username\ contains\ non\-ASCI\ characters/}

Net::NTLM::Message::Type3
  #serialize
    when the username contains non-ASCI characters
      serializes without error

Finished in 0.00835 seconds (files took 0.19049 seconds to load)
1 example, 0 failures

[pcai]

see inline

[pcai]

i think this change makes sense and behaves more like the comment block describes, since its supposed to be safe to perform byte concatenation on the result

[pcai]

thanks!