Here is the solution to the problem:

After installing BitOp which Ryan suggested in a previous message
(http://bitop.luajit.org/download.html) we we're still getting the same
error. The Lua script also has a require for rex_pcre, which we were
missing. 

This isn't available out of the Debian repo for Lenny so I've installed
it from the Ubuntu Lucid repo.

liblua5.1-rex-pcre0_2.4.0-1_amd64.deb
liblua5.1-rex-pcre-dev_2.4.0-1_amd64.deb

dependencies:

libpcre3_7.8-3build1_amd64.deb
libpcre3-dev_7.8-3build1_amd64.deb
libpcrecpp0_7.8-3build1_amd64.deb

Again, here is the original error:

Unknown  | Lua: Script execution failed: attempt to call a nil value
Unknown  | Rule processing failed.

I'm not sure if BitOp and rex_pcre are stated as requirements outside of the 
script, but it might be worth adding. (Apologies if I've missed it)

Thanks again for the assistance.
-Chris

On Mon, 2011-02-07 at 11:09 -0800, Chris Swanson wrote:
> Hi, we haven't had any luck with this issue, just wondering if anyone
> else has seen this or knows a solution?
> 
> Here is the original email and a response follow up with some
> suggestions.
> 
> Thanks
> -Chris
> 
> 
> 
> 
> On Wed, 2011-01-26 at 16:37 -0800, Chris Swanson wrote:
> > Hi, we're having a hard time with the new update(s) and Lua in our
> > testing environment. Here's the error we're seeing in Audit Console,
> > this is opening up a single transaction: 
> > 
> > Unknown  | Lua: Script execution failed: attempt to call a nil value
> > Unknown  | Rule processing failed.
> > 
> > 
> > This is happening with modsecurity 2.5.13 and modsec CRS 2.1.1 on
> > our
> > Debian 5 servers, apache is configured with:
> > 
> > ./configure --prefix=/usr/local/apache --disable-userdir
> > --enable-rewrite --enable-so --enable-info --enable-status
> > --enable-ssl
> > --enable-cgi --enable-unique-id --enable-mime-magic
> > --with-included-apr
> > --with-pcre=/usr/bin/pcre-config --enable-deflate --enable-expires
> > --enable-headers
> > 
> > modsecuirty cofigured with:
> > 
> > ./configure --with-apxs=/usr/local/apache/bin/apxs
> > --with-apr=/usr/local/apache/bin/apr-1-config
> > 
> > 
> > I've narrowed it down to the include in our http.conf for
> > modsecurity_crs_41_advanced_filters.conf, which was previously
> > working
> > as the phpids rules. Even further, by commenting out this section at
> > the
> > top of the 41_advanced_filters file everything works fine:
> > 
> > # Lua script to normalize input payloads
> > # Based on PHPIDS Converter.php code
> > # Reference the following whitepaper -
> > # http://docs.google.com/Doc?id=dd7x5smw_17g9cnx2cn 
> > # 
> > SecRuleScript ../lua/advanced_filter_converter.lua
> > "phase:2,t:none,pass"
> > SecRule TX:/centrifuge_ratio/ ".*"
> > "phase:2,t:none,log,capture,msg:'Centrifuge Threshold Alert - Ratio
> > Value is: %{tx.0}'"
> > 
> > 
> > Here is the modsecurity includes in our http.conf
> > 
> > #modsecurity Rules
> > Include conf/modsecurity.conf
> > Include conf/modsecurity-crs_2.1.1/*.conf
> > Include
> > conf/modsecurity-crs_2.1.1/experimental_rules/modsecurity_crs_41_advanced_filters.conf
> > Include
> > conf/modsecurity-crs_2.1.1/optional_rules/modsecurity_crs_25_cc_known.conf
> > Include conf/modsecurity-crs_2.1.1/base_rules/*conf
> > 
> > 
> > With the same setup and versions Modsecurity/Apache, CRS 2.0.10
> > worked
> > perfectly. We could move forward without Lua functionally, but I'm
> > lost
> > as to why such a big addition would be broken from the get-go.
> > Haven't
> > been able to find anyone posting with a similar issue so any help
> > would
> > be greatly appreciated.
> > 
> > 
> > Thanks,
> > -Chris
> > 
> 
> 
> > A couple questions -
> > 
> > 1) Did you modify the path to Lua in the script to point to your
> local
> > version?
> > 2) Did you install the additional bitop Lua module?
> > http://bitop.luajit.org/
> >    It is specified at the top of the script in a require statement.
> > This
> > is needed for the Octal to Decimal conversions.
> 
> I was missing Bitop, I've installed it from source, changed the
> install
> path for Debian, and I believe it's working as we can run the included
> bitbench.lua with no errors. The Lua problem still exists.
> 
> > 3) What was the request that triggered this error?
> 
> It triggers on any request, the one I've been using the most is
> accessing the page via IP instead of hostname, here's a breakdown of
> all
> the information regarding the request:
> 
> ----------------------
> 
> 
> Alert Messages:
> The following messages have been raised for this event:
>         Severity
>         Rule ID
>         Message
> UNKNOWN
> 
> Lua: Script execution
> failed: attempt to call
> a nil value
> Rule-Message:
> 
> UNKNOWN
> 
> Rule processing failed.
> Rule-Message:
> 
> 
> 
> Rules Section
> 
> The following rules have been fired for this event:
> SecAction phase:1 t:none nolog pass
> setvar:tx.anomaly_score_blocking=on
> SecAction phase:1 t:none nolog pass setvar:tx.critical_anomaly_score=5
> setvar:tx.error_anomaly_score=4 setvar:tx.warning_anomaly_score=3
> setvar:tx.notice_anomaly_score=2
> SecAction phase:1 t:none nolog pass
> setvar:tx.inbound_anomaly_score_level=5
> SecAction phase:1 t:none nolog pass
> setvar:tx.outbound_anomaly_score_level=4
> SecAction phase:1 t:none nolog pass setvar:tx.paranoid_mode=0
> SecAction phase:1 t:none nolog pass setvar:tx.max_num_args=255
> SecAction phase:1 t:none nolog pass setvar:'tx.allowed_methods=GET
> HEAD
> POST OPTIONS'
> setvar:'tx.allowed_request_content_type=application/x-www-form-urlencoded 
> multipart/form-data text/xml application/xml application/x-amf' 
> setvar:'tx.allowed_http_versions=HTTP/0.9 HTTP/1.0 HTTP/1.1' 
> setvar:'tx.restricted_extensions=.asa/ .asax/ .ascx/ .axd/ .backup/ .bak/ 
> .bat/ .cdx/ .cer/ .cfg/ .cmd/ .com/ .config/ .conf/ .cs/ .csproj/ .csr/ .dat/ 
> .db/ .dbf/ .dll/ .dos/ .htr/ .htw/ .ida/ .idc/ .idq/ .inc/ .ini/ .key/ .licx/ 
> .lnk/ .log/ .mdb/ .old/ .pass/ .pdb/ .pol/ .printer/ .pwd/ .resources/ .resx/ 
> .sql/ .sys/ .vb/ .vbs/ .vbproj/ .vsdisco/ .webinfo/ .xsd/ .xsx/' 
> setvar:'tx.restricted_headers=/Lock-Token/ /Content-Range/ /Translate/ /via/ 
> /if/'
> SecRule REQUEST_HEADERS:User-Agent @rx ^(.*)$ phase:1 t:none pass
> nolog
> t:sha1 t:hexEncode setvar:tx.ua_hash=%{matched_var}
> SecAction phase:1 t:none pass nolog initcol:global=global initcol:ip=
> %{remote_addr}_%{tx.ua_hash}
> SecAction phase:4 t:none nolog skipAfter:END_KNOWN_CC_OUTBOUND_CHECK\
> 
> 
> Request
> 
> GET / HTTP/1.1
> Host:
> 172.16.100.191
> Connection:
> keep-alive
> Accept:
> application/xml,application/xhtml
> +xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
> User-Agent:
> Mozilla/5.0 (X11; U; Linux x86_64;
> en-US) AppleWebKit/534.10 (KHTML,
> like Gecko) Chrome/8.0.552.200
> Safari/534.10
> Accept-Encoding:
> gzip,deflate,sdch
> Accept-Language:
> en-US,en;q=0.8
> Accept-Charset:
> ISO-8859-1,utf-8;q=0.7,*;q=0.3
> 
> 
> ----------------------
> 
> > You can still run it in this manner but since it will NOT be
> > normalizing
> > data in the same way as PHPIDS, there will be a higher % of false
> > positives/false negatives.
> > We did put this in the experimental directory after all ;) 
> 
> True enough!
> 
> >  Seriously, we
> > need more people to field test this new, advanced functionality.  I
> > applaud you for jumping in!  Don't give up on it, hopefully we can
> get
> > it
> > working for you.
> > 
> > -Ryan
> 
> Glad we can help out, we will keep on it until it's resolved.
> 
> -Chris
> > 
> 

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