When a rules match and fired filestore we may want
to increase the stream reassembly depth for this specific.
This add the 'depth' setting in file-store config,
which permits to specify how much data we want to reassemble
into a stream.
If a packet triggers a rule which contains both
bypass and filestore keywords,
it won't be stored since it's not inspected.
To avoid that, when a rule containing filestore keyword
we make sure that also bypass keyword is present.
To simplify locking, move all locking out of the individual detect
code. Instead at the start of detection lock the flow, and at the
end of detection unlock it.
The lua code can be called without a lock still (from the output
code paths), so still pass around a lock hint to take care of this.
The post match list was called with an unlocked flow until now.
However, recent de_state handling updates changed this. The stateful
detection code can now call the post match functions while keeping
the flow locked. The normal detection code still calls it with an
unlocked flow.
This patch adds a hint to the DetectEngineThreadCtx called
'flow_locked' that is set to true if the caller has already locked
the flow.
The Match functions don't need a pointer to the SigMatch object, just the
context pointer contained inside, so pass the Context to the Match function
rather than the SigMatch object. This allows for further optimization.
Change SigMatch->ctx to have type SigMatchCtx* rather than void* for better
type checking. This requires adding type casts when using or assigning it.
The SigMatch contex should not be changed by the Match() funciton, so pass it
as a const SigMatchCtx*.
SigMatch would be added to list, then the alproto check failed, leading
to freeing of sm. But as it was still in the list, the list now contained
a dangling pointer.
app-layer.[ch], app-layer-detect-proto.[ch] and app-layer-parser.[ch].
Things addressed in this commit:
- Brings out a proper separation between protocol detection phase and the
parser phase.
- The dns app layer now is registered such that we don't use "dnstcp" and
"dnsudp" in the rules. A user who previously wrote a rule like this -
"alert dnstcp....." or
"alert dnsudp....."
would now have to use,
alert dns (ipproto:tcp;) or
alert udp (app-layer-protocol:dns;) or
alert ip (ipproto:udp; app-layer-protocol:dns;)
The same rules extend to other another such protocol, dcerpc.
- The app layer parser api now takes in the ipproto while registering
callbacks.
- The app inspection/detection engine also takes an ipproto.
- All app layer parser functions now take direction as STREAM_TOSERVER or
STREAM_TOCLIENT, as opposed to 0 or 1, which was taken by some of the
functions.
- FlowInitialize() and FlowRecycle() now resets proto to 0. This is
needed by unittests, which would try to clean the flow, and that would
call the api, AppLayerParserCleanupParserState(), which would try to
clean the app state, but the app layer now needs an ipproto to figure
out which api to internally call to clean the state, and if the ipproto
is 0, it would return without trying to clean the state.
- A lot of unittests are now updated where if they are using a flow and
they need to use the app layer, we would set a flow ipproto.
- The "app-layer" section in the yaml conf has also been updated as well.
Improved accuracy, improved performance. Performance improvement
noticeable with http heavy traffic and ruleset.
A lot of other cosmetic changes carried out as well. Wrappers introduced
for a lot of app layer functions.
Failing dce unittests disabled. Will be reintroduced in the updated dce
engine.
Cross transaction matching taken care of. FPs emanating from these
matches have now disappeared. Double inspection of transactions taken
care of as well.
The output of the list-keyword is modified to include the url to
the keyword documentation when this is available. All documented
keywords should have their link set.
list-keyword can be used with an optional value:
no option or short: display list of keywords
csv: display a csv output on info an all keywords
all: display a human readable output of keywords info
$KWD: display the info about one keyword.
When handling error case on SCMallog, SCCalloc or SCStrdup
we are in an unlikely case. This patch adds the unlikely()
expression to indicate this to gcc.
This patch has been obtained via coccinelle. The transformation
is the following:
@istested@
identifier x;
statement S1;
identifier func =~ "(SCMalloc|SCStrdup|SCCalloc)";
@@
x = func(...)
... when != x
- if (x == NULL) S1
+ if (unlikely(x == NULL)) S1
The filestore keyword until now flagged a file, tx or ssn for storage as soon
as the keyword was inspected. This happens before flowbits and some other
keywords, so files were stored that weren't supposed to.
This patch makes the filestore keyword fill an array in the detect engine
thread ctx. Then if the full signature matches, a post-match filestore
function makes the store final.
Filestore keyword by default (... filestore; ... ) marks only the file in the
same direction as the rule match for storing. This makes sense when inspecting
individual files (filemagic, filename, etc) but not so much when looking at
suspicious file requests, where the actual file is in the response.
The filestore keyword now takes 2 optional options:
filestore:<direction>,<scope>;
By default the direction is "same as rule match", and scope is "currently
inspected file".
For direction the following values are possible: "request" and "to_server",
"response" and "to_client", "both".
For scope the following values are possible: "tx" for all files in the current
HTTP/1.1 transation, "ssn" and "flow" for all files in the session/flow.
For the above case, where a suspious request should lead to a response file
download, this would work:
alert http ... content:"/suspicious/"; http_uri; filestore:response; ...
Victor Julien
Eric Leblond
Giuseppe Longo
Ken Steele
David Abarbanel
Anoop Saldanha
Last G