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111 lines
2.9 KiB
Text
111 lines
2.9 KiB
Text
##! Activates port-independent protocol detection and selectively disables
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##! analyzers if protocol violations occur.
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module DPD;
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@load-sigs ./dpd.sig
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export {
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## Add the DPD logging stream identifier.
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redef enum Log::ID += { LOG };
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## The record type defining the columns to log in the DPD logging stream.
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type Info: record {
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## Timestamp for when protocol analysis failed.
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ts: time &log;
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## Connection unique ID.
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uid: string &log;
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## Connection ID containing the 4-tuple which identifies endpoints.
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id: conn_id &log;
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## Transport protocol for the violation.
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proto: transport_proto &log;
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## The analyzer that generated the violation.
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analyzer: string &log;
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## The textual reason for the analysis failure.
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failure_reason: string &log;
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## Disabled analyzer IDs. This is only for internal tracking
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## so as to not attempt to disable analyzers multiple times.
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disabled_aids: set[count];
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};
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## Ignore violations which go this many bytes into the connection.
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## Set to 0 to never ignore protocol violations.
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const ignore_violations_after = 10 * 1024 &redef;
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}
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redef record connection += {
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dpd: Info &optional;
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};
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event bro_init() &priority=5
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{
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Log::create_stream(DPD::LOG, [$columns=Info]);
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# Populate the internal DPD analysis variable.
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for ( a in dpd_config )
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{
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for ( p in dpd_config[a]$ports )
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{
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if ( p !in dpd_analyzer_ports )
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dpd_analyzer_ports[p] = set();
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add dpd_analyzer_ports[p][a];
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}
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}
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}
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event protocol_confirmation(c: connection, atype: count, aid: count) &priority=10
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{
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local analyzer = analyzer_name(atype);
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if ( fmt("-%s",analyzer) in c$service )
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delete c$service[fmt("-%s", analyzer)];
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add c$service[analyzer];
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}
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event protocol_violation(c: connection, atype: count, aid: count,
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reason: string) &priority=10
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{
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local analyzer = analyzer_name(atype);
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# If the service hasn't been confirmed yet, don't generate a log message
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# for the protocol violation.
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if ( analyzer !in c$service )
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return;
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delete c$service[analyzer];
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add c$service[fmt("-%s", analyzer)];
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local info: Info;
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info$ts=network_time();
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info$uid=c$uid;
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info$id=c$id;
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info$proto=get_conn_transport_proto(c$id);
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info$analyzer=analyzer;
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info$failure_reason=reason;
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c$dpd = info;
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}
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event protocol_violation(c: connection, atype: count, aid: count, reason: string) &priority=5
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{
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if ( !c?$dpd || aid in c$dpd$disabled_aids )
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return;
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local size = c$orig$size + c$resp$size;
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if ( ignore_violations_after > 0 && size > ignore_violations_after )
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return;
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# Disable the analyzer that raised the last core-generated event.
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disable_analyzer(c$id, aid);
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add c$dpd$disabled_aids[aid];
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}
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event protocol_violation(c: connection, atype: count, aid: count,
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reason: string) &priority=-5
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{
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if ( c?$dpd )
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{
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Log::write(DPD::LOG, c$dpd);
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delete c$dpd;
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}
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}
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