The SMB::State$recent_files field is meant to have expiring entries.
However, due to usage of &default=string_set(), the &read_expire
attribute is not respected causing unbounded state growth. Replace
&default=string_set() with &default=set().
Thanks to ya-sato on Slack for reporting!
Related: zeek/zeek-docs#179, #3513.
This is similar to what the external corelight/zeek-smb-clear-state script
does, but leverages the smb2_discarded_messages_state() event instead of
regularly checking on the state of SMB connections.
The pcap was created using the dperson/samba container image and mounting
a share with Linux's CIFS filesystem, then copying the content of a
directory with 100 files. The test uses a BPF filter to imitate mostly
"half-duplex" traffic.
This avoids a problem identified by amanbansal2709 in pull
request #1288. I fixed it in a different way than that pull request
by making sure the ts field is always set so that this isssue doesn't
return in the future.
This adds a "policy" hook into the logging framework's streams and
filters to replace the existing log filter predicates. The hook
signature is as follows:
hook(rec: any, id: Log::ID, filter: Log::Filter);
The logging manager invokes hooks on each log record. Hooks can veto
log records via a break, and modify them if necessary. Log filters
inherit the stream-level hook, but can override or remove the hook as
needed.
The distribution's existing log streams now come with pre-defined
hooks that users can add handlers to. Their name is standardized as
"log_policy" by convention, with additional suffixes when a module
provides multiple streams. The following adds a handler to the Conn
module's default log policy hook:
hook Conn::log_policy(rec: Conn::Info, id: Log::ID, filter: Log::Filter)
{
if ( some_veto_reason(rec) )
break;
}
By default, this handler will get invoked for any log filter
associated with the Conn::LOG stream.
The existing predicates are deprecated for removal in 4.1 but continue
to work.
