SECURITY (CVE-2014-0117): Fix a crash in mod_proxy. In a reverse

SECURITY (CVE-2014-0117): Fix a crash in mod_proxy.  In a reverse
proxy configuration, a remote attacker could send a carefully crafted
request which could crash a server process, resulting in denial of
service.

Thanks to Marek Kroemeke working with HP's Zero Day Initiative for
reporting this issue.

* server/util.c (ap_parse_token_list_strict): New function.

* modules/proxy/proxy_util.c (find_conn_headers): Use it here.

* modules/proxy/mod_proxy_http.c (ap_proxy_http_process_response):
  Send a 400 for a malformed Connection header.

Submitted by: Edward Lu, breser, covener

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1610674 13f79535-47bb-0310-9956-ffa450edef68