[TS-3100] Extend the tr-pass window to allow malformed HTTP commands to be blind tunneled

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 5.3.0
• Assignee: Susan Hinrichs
• Reporter: Susan Hinrichs
• Created: 27/Sep/14 01:05
• Updated: 13/May/15 20:36
• Resolved: 22/Jan/15 14:30

Description

Some servers abuse the HTTP protocol to implement services. ATS certainly should not cache responses from malformed GET, POST, etc, it should get out of the way if possible and pass the traffic along if the customer has marked the port with tr-pass.

As the code is currently written, it will make the tr-pass blind tunnel decision if the initial request does not parse. But if the initial request does parse but the specification violation occurs later, the tr-pass decision is not revisited.

One ISP using ATS has reported the following scenarios. The client sends a well formed GET request. Then after the double carriage return line feeds, it sends some additional text. The server interprets this as additional requests for information.

Since the GET request was well formed, the connection is put on the HTTP path and the extra data after the carriage return line feeds is stripped before it is passed along to the server.

At a minimum, I want to revisit tr-pass decision after the header has been parsed and the carriage return line feeds have been read in the GET case. If the connection is not set to pipeline requests and there is more data in the buffer, pass the connection on to be blind tunneled.

I plan to review the POST and PUT paths for other early options for tr-pass evaluations too.

Issue Links

• depends upon: TS-3202 HTTP Parsing should not allow CTL characters in the method
• depends upon: TS-3155 Add a value test method to the MIMEField class