zeek/scripts/base/files/ocsp/main.bro

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@load base/frameworks/files
@load base/utils/paths
@load base/utils/queue
module OCSP;
export {
## add one more argument to tell ocsp response or request
redef record Files::AnalyzerArgs += {
ocsp_type: string &optional;
};
## ocsp logging
redef enum Log::ID += { LOG };
## type for pending ocsp request
type PendingRequests: table[OCSP::CertId] of Queue::Queue;
## NOTE: one file could contain several requests
## one ocsp request record
type Info_req: record {
## time for the request
ts: time;
## file id for this request
id: string &log;
## connection id
cid: conn_id &optional;
## connection uid
cuid: string &optional;
## version
version: count &log &optional;
## requestor name
requestorName: string &log &optional;
## NOTE: the above are for one file which may contain
## several ocsp requests
## request cert id
certId: OCSP::CertId &optional;
};
## NOTE: one file could contain several response
## one ocsp response record
type Info_resp: record {
## time for the response
ts: time;
## file id for this response
id: string &log;
## connection id
cid: conn_id &optional;
## connection uid
cuid: string &optional;
## responseStatus (different from cert status?)
responseStatus: string &log;
## responseType
responseType: string &log;
## version
version: count &log;
## responderID
responderID: string &log;
## producedAt
producedAt: string &log;
## NOTE: the following are specific to one cert id
## the above are for one file which may contain
## several responses
##cert id
certId: OCSP::CertId &optional;
## certStatus (this is the response to look at)
certStatus: string &log &optional;
## thisUpdate
thisUpdate: string &log &optional;
## nextUpdate
nextUpdate: string &log &optional;
};
type Info: record {
## timestamp for request if a corresponding request is present
## OR timestamp for response if a corresponding request is not found
ts: time &log;
## connection id
cid: conn_id &log;
## connection uid
cuid: string &log;
## cert id
certId: OCSP::CertId &log &optional;
## request
req: Info_req &log &optional;
## response timestamp
resp_ts: time &log &optional;
## response
resp: Info_resp &log &optional;
};
## Event for accessing logged OCSP records.
global log_ocsp: event(rec: Info);
}
redef record connection += {
## keep track of pending requests received so for
ocsp_requests: PendingRequests &optional;
};
event bro_init() &priority=5
{
Log::create_stream(LOG, [$columns=Info, $ev=log_ocsp, $path="ocsp"]);
}
function get_http_info(f: fa_file, meta: fa_metadata)
{
if (f$source != "HTTP" || !meta?$mime_type)
return;
# call OCSP file analyzer
if (meta$mime_type == "application/ocsp-request")
Files::add_analyzer(f, Files::ANALYZER_OCSP, [$ocsp_type = "request"]);
else if (meta$mime_type == "application/ocsp-response")
Files::add_analyzer(f, Files::ANALYZER_OCSP, [$ocsp_type = "response"]);
}
event file_sniff(f: fa_file, meta: fa_metadata) &priority = 5
{
if (f$source == "HTTP")
get_http_info(f, meta);
}
event ocsp_request(f: fa_file, req_ref: opaque of ocsp_req, req: OCSP::Request) &priority = 5
{
local conn: connection;
local cid: conn_id;
# there should be only one loop: one connection
for (id in f$conns)
{
cid = id;
conn = f$conns[id];
}
if (req?$requestList)
{
for (x in req$requestList)
{
local one_req = req$requestList[x];
local cert_id: OCSP::CertId = [$hashAlgorithm = one_req$hashAlgorithm,
$issuerNameHash = one_req$issuerNameHash,
$issuerKeyHash = one_req$issuerKeyHash,
$serialNumber = one_req$serialNumber];
local req_rec: Info_req = [$ts=network_time(), $id=f$id, $certId=cert_id, $cid=conn$id, $cuid=conn$uid];
if (req?$version)
req_rec$version = req$version;
if (req?$requestorName)
req_rec$requestorName = req$requestorName;
if (!conn?$ocsp_requests)
conn$ocsp_requests = table();
if (cert_id !in conn$ocsp_requests)
conn$ocsp_requests[cert_id] = Queue::init();
Queue::put(conn$ocsp_requests[cert_id], req_rec);
}
}
else
{
# no request content? this is weird but log it anyway
local req_rec_empty: Info_req = [$ts=network_time(), $id=f$id, $cid=conn$id, $cuid=conn$uid];
if (req?$version)
req_rec_empty$version = req$version;
if (req?$requestorName)
req_rec_empty$requestorName = req$requestorName;
Log::write(LOG, [$ts=req_rec_empty$ts, $req=req_rec_empty, $cid=conn$id, $cuid=conn$uid]);
}
}
event ocsp_response(f: fa_file, resp_ref: opaque of ocsp_resp, resp: OCSP::Response) &priority = 5
{
local conn: connection;
local cid: conn_id;
# there should be only one loop
for (id in f$conns)
{
cid = id;
conn = f$conns[id];
}
if (resp?$responses)
{
for (x in resp$responses)
{
local single_resp: OCSP::SingleResp = resp$responses[x];
local cert_id: OCSP::CertId = [$hashAlgorithm = single_resp$hashAlgorithm,
$issuerNameHash = single_resp$issuerNameHash,
$issuerKeyHash = single_resp$issuerKeyHash,
$serialNumber = single_resp$serialNumber];
local resp_rec: Info_resp = [$ts = network_time(), $id = f$id,
$cid=conn$id, $cuid=conn$uid,
$responseStatus = resp$responseStatus,
$responseType = resp$responseType,
$version = resp$version,
$responderID = resp$responderID,
$producedAt = resp$producedAt,
$certId = cert_id,
$certStatus = single_resp$certStatus,
$thisUpdate = single_resp$thisUpdate];
if (single_resp?$nextUpdate)
resp_rec$nextUpdate = single_resp$nextUpdate;
if (conn?$ocsp_requests && cert_id in conn$ocsp_requests)
{
# find a match
local req_rec: Info_req = Queue::get(conn$ocsp_requests[cert_id]);
Log::write(LOG, [$ts=req_rec$ts, $certId=req_rec$certId, $req=req_rec, $resp_ts=resp_rec$ts, $resp=resp_rec, $cid=conn$id, $cuid=conn$uid]);
if (Queue::len(conn$ocsp_requests[cert_id]) == 0)
delete conn$ocsp_requests[cert_id]; #if queue is empty, delete it?
}
else
{
# do not find a match; this is weird but log it
Log::write(LOG, [$ts=resp_rec$ts, $certId=resp_rec$certId, $resp_ts=resp_rec$ts, $resp=resp_rec, $cid=conn$id, $cuid=conn$uid]);
}
}
}
else
{
# no response content? this is weird but log it anyway
local resp_rec_empty: Info_resp = [$ts=network_time(), $id=f$id,
$cid=conn$id, $cuid=conn$uid,
$responseStatus = resp$responseStatus,
$responseType = resp$responseType,
$version = resp$version,
$responderID = resp$responderID,
$producedAt = resp$producedAt];
Log::write(LOG, [$ts=resp_rec_empty$ts, $resp_ts=resp_rec_empty$ts, $resp=resp_rec_empty, $cid=conn$id, $cuid=conn$uid]);
}
}
function log_unmatched_msgs_queue(q: Queue::Queue)
{
local reqs: vector of Info_req;
Queue::get_vector(q, reqs);
for ( i in reqs )
Log::write(LOG, [$ts=reqs[i]$ts, $certId=reqs[i]$certId, $req=reqs[i], $cid=reqs[i]$cid, $cuid=reqs[i]$cuid]);
}
function log_unmatched_msgs(msgs: PendingRequests)
{
for ( cert_id in msgs )
log_unmatched_msgs_queue(msgs[cert_id]);
clear_table(msgs);
}
# need to log unmatched ocsp request if any
event connection_state_remove(c: connection) &priority= -5
{
if (! c?$ocsp_requests)
return;
log_unmatched_msgs(c$ocsp_requests);
}