Initial handshake problem

[jasdefer]

When connecting to my 10.0.31-MariaDB database, I get an exception during the initial handshake.
The problem occurs while reading the AuthPluginName. The FormatException Read past end of buffer looking for NUL. is thrown in the MySql.Data.ByteArrayReader.ReadNullTerminatedByteString() method. Even though the AuthPluginName should be mysql_native_password (see the provided byte buffer below).

m_offset=71, m_maxOffset=92 and the buffer (m_buffer) is

    [...]
    [70]: 0
    [71]: 109
    [72]: 121
    [73]: 115
    [74]: 113
    [75]: 108
    [76]: 95
    [77]: 110
    [78]: 97
    [79]: 116
    [80]: 105
    [81]: 118
    [82]: 101
    [83]: 95
    [84]: 112
    [85]: 97
    [86]: 115
    [87]: 115
    [88]: 119
    [89]: 111
    [90]: 114
    [91]: 100
    [92]: 0
    [93]: 0
    [94]: 0

I understand that index == m_maxOffset is true and therefore the exception is thrown.
When removing the following two lines from the ReadNullTerminatedByteString method, the connection can be established without any problems:

if (index == m_maxOffset)
    throw new FormatException("Read past end of buffer looking for NUL.");

I obviously don't want to remove those lines for production. Can someone help me out?

[bgrainger]

I'm not seeing this exception when running the tests against the mariadb:10.0.32 Docker image. Would it be possible for you to perform a packet capture (with Wireshark, tcpdump or similar) and attach it here (or email it to me privately)?

[jasdefer]

I just use Wireshark to capture the packets. I noticed the following package using the MySQL protocol with the info Server Greeting proto=10 version=5.5.5-10.0.31-MariaDB[Malformed Packet].
I assume the problem is the malformed packet, but I can send you all the packages if it helps.

[bgrainger]

Yes, the malformed packet does sound like the problem (and it would appear that Wireshark's protocol analyser also identifies there is a problem).

Do you have a direct connection to your MariaDB server, or is there some some of proxy / load balancer / etc. in between?

[jasdefer]

Even with the malformed packet I still get the message (when following the TCP stream in Wireshark):

X...
5.5.5-10.0.31-MariaDB.#"	.]|{rIX[B...!..?............wSuvoJa-YZ8E.mysql_native_password

The database is really behind something, I think a proxy. I just asked the system administrator for details. I will post his answer when he replies.

Thank you for your help so far :)

[jasdefer]

I just got a response:
The database is only accessible when connected to the same network as the database (which I am). There is a MySQL proxy in front of the database. The whole thing is behind a service chain with a load balancer. The load balancer sends the requests of a session always to the same MySQL proxy.

[bgrainger]

I just found this in the archived docs:

• auth_plugin_name (string.NUL) -- name of the auth_method that the auth_plugin_data belongs to

Note
Due to Bug#59453 the auth-plugin-name is missing the terminating NUL-char in versions prior to 5.5.10 and 5.6.2.

I'll update the connector to not require a null-terminator.

[bgrainger]

Fixed in 0.28.2.

[jasdefer]

Awesome it works! Thank you very much.