File transfer handshaker no accessories2/11/2024 ![]() SqlClient //A test class public class SimpleConnect Ĭonsole. I also captured the tdsproxy to MSSQL server conversation as well - take a look at both: NET SqlClient looks slightly different in the SSL handshake part, so direct comparison with the Java JDBC client (see my previous attachment) is not possible, unfortunately. And I see No problem (e.g running scripts, pulling huge result sets through my double-encrypted TDS proxy)! Both connections, front and back ,are forced into complete session SSL (not just during the LOGIN exchange). NET SqlClient (see below) - it works just fine! My TDS server acts like a proxy - it connects on the front with SqlClient and on the back - with true MS SQL Server 2019 instance. In addition, I just tested my TDS server proxy with a simple. As I mentioned in the report, (the latest) Micosoft SQL Management Studio and the (latest) new Azure Data Studio do not exhibit such SSL handshake problems, work flawlessly after establishing the connection with my TDS server. I could be the MS JDBC driver works with MS SQL Server only because the later is not very strict. The TDS server, still expected SSL handshake message (wrapped as TDS messages) attempts to parse the TDS packet header and blows up with "Unknown value: 23" for the message My expectation was that the MS SQL JDBC driver complies with the TDS protocol. This is confirmed by the network capture file, where screenshot2 shows the TDS server never receiving the 90 bytes finishing SSL handshake message, but directly forced to deal with the LOGIN message of size 373. Without properly confirming the end of the SSL handshake, the client assume SSL connection has been established, and proceeds to build a LOGIN message of size 355 bytes (line:361 - line: 423) that it eventually sends to the TDS server as encrypted payload of 373 bytes (see line 419). However, line:360 shows the "flushing the stream" never happens!. The logs indicate that from line:308 the client starts building up such a response, which is made ready by line:352-line:356, where 90 bytes are supposed to be sent to the TDS server. The client is expected to send a final SSL handshake confirmation message to the TDS server This is independently confirmed with screenshot1 from the WireShark capture file, which shows a payload of exactly 2463 bytes sent to the client (2455+8=2463, TDS header is 8 bytes). Line 138 in the log confirms that the client has received the last SSL handshake payload of 2455 bytes from the TDS server, and the messages from line:293-line:350 show the client parsing SSL chunks and is trusting the TDS server certificate (line:350). You need to install WireShark to browse the network capture file, but I have also attached 2 screenshots for your convenience. This may require more explanation, but you should see the payloads and their sizes exchanged with the client.Ī network capture file (produced by the WireShark free tool) that tracks independently the communications between the JDBC client and the TDS server. A detailed log from MS SQL JDBC driver attempting to connect with some trivial code, like:ĭriverManager.getConnection("jdbc:sqlserver://127.0.0.1:1437 user=test password=test encrypt=true trustServerCertificate=true") Ī detail log from the TDS server.NET clients - all tested against the same TDS server. Such behavior is not observed with other TDS clients such as Microsoft SQL Management Studio, Azure Data Studio. In particular, it fails to to execute a last confirmation step and send finishing message to the TDS server. My tests shows that the JDBC Driver fails to execute the SSL Handshake properly and a proper TDS server would fail the connection due to unfinished SSL handshake. Microsoft's TDS document (see section 2.2.6.5 PRELOGIN) specify that during PRE-LOGIN message exchange the client and the server can execute SSL handshake protocol to establish secure connection (whether only for the subsequent LOGIN or for the entire session). TDS compliant server proxy Client Operating System 9.4.0.jre16 (latest from Maven central repo) SQL Server version
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