general/5819: Host: header field with an underscore fails with "Client sent malformed Host header"

[Michael Cramer <mc...@pbs.org>]

>Number:         5819
>Category:       general
>Synopsis:       Host: header field with an underscore fails with "Client sent malformed Host header"
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apache
>State:          open
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Mon Feb 28 16:10:00 PST 2000
>Closed-Date:
>Last-Modified:
>Originator:     mcramer@pbs.org
>Release:        1.3.12
>Organization:
apache
>Environment:
Solaris 2.6, gcc, SunOS nfs 5.6 Generic_105181-16 sun4u sparc SUNW,Ultra-4
>Description:
The error checking of the Host: header which was added in 1.3.10 breaks requests
that refer to hostnames containing an underscore. This was first reported in 
PR#5722 regarding Virtual Hosts, but it appears that it happens in servers which
do not use virtual hosts at all.
>How-To-Repeat:
In your /etc/hosts file, add an alias for your webserver's IP, using 
telnet to a 1.3.10 or newer server on port 80 and give the following:
GET / HTTP/1.1
Host: blah_zing
>Fix:
It looks like the problem is in the fix_hostname function in main/http_vhost.c.
>Release-Note:
>Audit-Trail:
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