[ANN] unicorn 0.97.1 - fix HTTP parser for Rainbows!/Zbatery

Eric Wong normalperson at yhbt.net
Mon Apr 19 17:28:50 EDT 2010

Unicorn is an HTTP server for Rack applications designed to only serve
fast clients on low-latency, high-bandwidth connections and take
advantage of features in Unix/Unix-like kernels.  Slow clients should
only be served by placing a reverse proxy capable of fully buffering
both the the request and response in between Unicorn and slow clients.

* http://unicorn.bogomips.org/
* mongrel-unicorn at rubyforge.org
* git://git.bogomips.org/unicorn.git


This release fixes a denial-of-service vector for derived
servers exposed directly to untrusted clients.

This bug does not affect most Unicorn deployments as Unicorn is
only supported with trusted clients (such as nginx) on a LAN.
nginx is known to reject clients that send invalid
Content-Length headers, so any deployments on a trusted LAN
and/or behind nginx are safe.

Servers affected by this bug include (but are not limited to)
Rainbows! and Zbatery.  This bug does not affect Thin nor
Mongrel, as neither got the request body filtering treatment
that the Unicorn HTTP parser got in August 2009.

The bug fixed in this release could result in a
denial-of-service as it would trigger a process-wide assertion
instead of raising an exception.  For servers such as
Rainbows!/Zbatery that serve multiple clients per worker
process, this could abort all clients connected to the
particular worker process that hit the assertion.

Eric Wong

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