[Oisf-devel] libhtp 0.5.x integration - bug 775

Anoop Saldanha anoopsaldanha at gmail.com
Wed May 15 06:37:54 UTC 2013


Ivan,

I see the introduction of

htp_tx_t *htp_connp_get_in_tx(const htp_connp_t *connp);
htp_tx_t *htp_connp_get_out_tx(const htp_connp_t *connp);

Which means I won't be able to retrieve individual txs?  I receive 5
pipelined requests, so that would be 5 txs created.  How do I retrieve
the individual txs?

On Thu, Apr 11, 2013 at 10:16 PM, Anoop Saldanha
<anoopsaldanha at gmail.com> wrote:
> On Thu, Apr 11, 2013 at 9:10 PM, Ivan Ristic <ivan.ristic at gmail.com> wrote:
>> I wouldn't advise you to do any buffering anyhow.
>> But I am curious if you're
>> deleting transactions once you're done with them. Because, if you're not,
>> you may be allocating a lot of memory (all tx instances) on long-lived HTTP
>> connections.
>>
>
> We do delete them, once we're done.
>
>>
>> On Tue, Apr 9, 2013 at 1:06 PM, Anoop Saldanha <anoopsaldanha at gmail.com>
>> wrote:
>>>
>>> On Tue, Apr 9, 2013 at 2:36 PM, Victor Julien <victor at inliniac.net> wrote:
>>> > (bad juju to brian and ivan for top posting and/or html emails! :)
>>> >
>>> > On 04/09/2013 10:21 AM, Ivan Ristic wrote:
>>> >> On Mon, Apr 8, 2013 at 3:54 PM, Anoop Saldanha <anoopsaldanha at gmail.com
>>> >> <mailto:anoopsaldanha at gmail.com>> wrote:
>>> >>
>>> >>     On Mon, Apr 8, 2013 at 7:50 PM, Brian Rectanus <brectanu at gmail.com
>>> >>     <mailto:brectanu at gmail.com>> wrote:
>>> >>     >
>>> >>     > On Mon, Apr 8, 2013 at 9:16 AM, Brian Rectanus
>>> >> <brectanu at gmail.com
>>> >>     <mailto:brectanu at gmail.com>> wrote:
>>> >>     >>
>>> >>     >>
>>> >>     >> On Mon, Apr 8, 2013 at 8:47 AM, Anoop Saldanha
>>> >>     <anoopsaldanha at gmail.com <mailto:anoopsaldanha at gmail.com>>
>>> >>     >> wrote:
>>> >>     >>>
>>> >>     >>> On Mon, Apr 8, 2013 at 3:42 PM, Victor Julien
>>> >>     <victor at inliniac.net <mailto:victor at inliniac.net>>
>>> >>     >>> wrote:
>>> >>     >>> > (moving to oisf-devel)
>>> >>     >>> >
>>> >>     >>> > On 04/08/2013 06:17 AM, Anoop Saldanha wrote:
>>> >>     >>> >>>> I recollect we introduced path and query double decoding
>>> >>     through
>>> >>     >>> >>>> configurable params, and also we had this thing with query
>>> >>     >>> >>>> decoding(single level).  Can you explain a bit what the
>>> >>     status was
>>> >>     >>> >>>> previously.  Seeing related failed uts.
>>> >>     >>> >>>>
>>> >>     >>> >>>
>>> >>     >>> >>> We run the path normalization on the query through our
>>> >>     >>> >>> HTPCallbackRequestUriNormalizeQuery callback. Previously we
>>> >> used
>>> >>     >>> >>> htp_decode_path_inplace to normalize the query (e.g. for
>>> >>     >>> >>> uridecoding).
>>> >>     >>> >>> However, this was causing issues (remember that pcre "bug"
>>> >> we
>>> >>     >>> >>> discussed
>>> >>     >>> >>> a while back, where http:// turned into http:/).
>>> >>     >>> >>>
>>> >>     >>> >>> In libhtp I copied htp_decode_path_inplace to
>>> >>     >>> >>> htp_decode_query_inplace
>>> >>     >>> >>> and also copied the config params and cfg funcs:
>>> >>     >>> >>>
>>> >>     >>> >>>
>>> >>
>>> >> https://github.com/inliniac/suricata/commit/d41c762689a08e6814dc93e8bfebeceab97175c3
>>> >>     >>> >>>
>>> >>     >>> >>> Hack of the 1st order, which is wrong in many ways. But it
>>> >>     basically
>>> >>     >>> >>> allowed me to make sure we don't normalize the query as if
>>> >>     it's path,
>>> >>     >>> >>> esp with turning ftp:// into ftp:/ and such.
>>> >>     >>> >>>
>>> >>     >>> >>> For 0.5 integration I think we need a proper solution. The
>>> >> only
>>> >>     >>> >>> reason I
>>> >>     >>> >>> pushed my hack like this was that I knew in 0.5 we would
>>> >>     make things
>>> >>     >>> >>> right.
>>> >>     >>> >>>
>>> >>     >>> >>
>>> >>     >>> >> I think if we still want to double decode, we still require
>>> >>     all of
>>> >>     >>> >> these above things from our bundled htp.
>>> >>     >>> >>
>>> >>     >>> >> -----
>>> >>     >>> >>
>>> >>     >>> >> In 0.5.x, tx->request_uri_normalized has been removed, and
>>> >>     we'd now
>>> >>     >>> >> have to use the REQUEST_URI hook.  We'll have to carry out
>>> >> the
>>> >>     >>> >> reconstruction ourselves, and store it ourselves in our
>>> >> HTPState.
>>> >>     >>> >>
>>> >>     >>>
>>> >>     >>> What are your thoughts on this?
>>> >>     >>>
>>> >>     >>> >
>>> >>     >>> > IIRC there is some function in libhtp that does just the
>>> >>     decoding of
>>> >>     >>> > uriencoding and unicode. We should probably just use that on
>>> >>     the query
>>> >>     >>> > and do the full normalization on the path.
>>> >>     >>> >
>>> >>     >>> > As a side thought: I think it would be nice to store path and
>>> >>     query
>>> >>     >>> > separately so that we can add http_path and http_query
>>> >>     keywords later
>>> >>     >>> > on.
>>> >>     >>> >
>>> >>     >>>
>>> >>     >>> We'd pretty much extract it directly from parsed_uri.  Will
>>> >> have to
>>> >>     >>> check if we need the extract double decode phase we have
>>> >>     currently in
>>> >>     >>> our bundled htp, in which case we'd need to store them
>>> >> separately.
>>> >>     >>>
>>> >>     >>
>>> >>     >> Yes, all the normalized components are in tx->parsed_uri.  This
>>> >>     is what is
>>> >>     >> used in ironbee to expose all the various parts like
>>> >>     tx->parsed_uri->path
>>> >>     >> and tx->parsed_uri->query.
>>> >>     >>
>>> >>     >> Also note that the hostname should now be obtained from
>>> >>     >> tx->request_hostname in 0.5.
>>> >>     >>
>>> >>     >> -B
>>> >>     >
>>> >>     >
>>> >>     > FYI, for an example using libhtp 0.5 see ironbee code.  This was
>>> >> all
>>> >>     > recently updated for 0.5.
>>> >>     >
>>> >>     > https://github.com/ironbee/ironbee/blob/0.7.x/modules/modhtp.c
>>> >>     >
>>> >>
>>> >>     Will have a look.  Thanks.
>>> >>
>>> >>     Previously we would use tx->connp->conn->transactions to access txs
>>> >>     in the state.  Now that htp_connp_t is an opaque pointer how do I
>>> >>     access the txs? Tried locating helper functions to retrieve it, but
>>> >> I
>>> >>     didn't find any.
>>> >>
>>> >> It's an oversight that there isn't a helper function to retrieve
>>> >> transactions on a connections. I will add one tomorrow.
>>> >>
>>> >> Having said that, what is your use case that you require to retrieve
>>> >> transactions? I thought your code was driven by the callbacks, which >
>>> >> all
>>> >> come with a tx instance (via connp)? For my education, can you explain
>>> >> how you process connection data?
>>> >>
>>> >>
>>> >
>>> > One of the things that we don't do out of the callbacks is logging the
>>> > requests. This is one of the things we need access to the TX store for.
>>> >
>>>
>>> And to add to it, since we already have the txs stored in a list
>>> inside libhtp, re-buffering the txs would come as a redundant task,
>>> from where I see it.
>>>
>>> --
>>> Anoop Saldanha
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>>
>>
>>
>>
>> --
>> Ivan Ristić
>
>
>
> --
> Anoop Saldanha



-- 
Anoop Saldanha


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