zeek/scripts/base/protocols/mime/base.bro
Jon Siwek 4ac6d0ae2e Fixes for script auto-documentation.
- Fixing the parts of the `make restdoc` and `make doc` process that were
  broken by the last Bro script re-organization

- Generated documentation for Bro scripts derived from BiFs now use the
  original BiF source file as the "original source file" link

- Renaming of the internal POLICYDEST definition and other misc places that
  refer to "policy" scripts; that terminology doesn't make total sense now

- Added a documentation blacklist reminder test that will fail if there's
  scripts that are blacklisted from being documentated because they're still
  in progress

- Some minor Bro script changes to fix small @load dependency errors

Addresses #543
2011-08-08 19:50:45 -05:00

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2.6 KiB
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##! The mime script does analysis of MIME encoded messages seen in certain
##! protocols (only SMTP and POP3 at the moment).
@load base/utils/strings
module MIME;
export {
redef enum Log::ID += { MIME };
# Let's assume for now that nothing transferring files using
# MIME attachments is multiplexing for simplicity's sake.
# We can make the assumption that one connection == one file (at a time)
type Info: record {
## This is the timestamp of when the MIME content transfer began.
ts: time &log;
uid: string &log;
id: conn_id &log;
## The application layer protocol over which the transfer was seen.
app_protocol: string &log &optional;
## The filename seen in the Content-Disposition header.
filename: string &log &optional;
## Track how many byte of the MIME encoded file have been seen.
content_len: count &log &default=0;
};
type State: record {
## Track the number of MIME encoded files transferred during this session.
level: count &default=0;
};
global log_mime: event(rec: Info);
}
redef record connection += {
mime: Info &optional;
mime_state: State &optional;
};
event bro_init()
{
Log::create_stream(MIME, [$columns=Info, $ev=log_mime]);
}
function new_mime_session(c: connection): Info
{
local info: Info;
info$ts=network_time();
info$uid=c$uid;
info$id=c$id;
return info;
}
function set_session(c: connection, new_entity: bool)
{
if ( ! c?$mime_state )
c$mime_state = [];
if ( ! c?$mime || new_entity )
c$mime = new_mime_session(c);
}
event mime_begin_entity(c: connection) &priority=10
{
set_session(c, T);
++c$mime_state$level;
if ( |c$service| > 0 )
c$mime$app_protocol = join_string_set(c$service, ",");
}
# This has priority -10 because other handlers need to know the current
# content_len before it's updated by this handler.
event mime_segment_data(c: connection, length: count, data: string) &priority=-10
{
c$mime$content_len = c$mime$content_len + length;
}
event mime_one_header(c: connection, h: mime_header_rec)
{
if ( h$name == "CONTENT-DISPOSITION" &&
/[fF][iI][lL][eE][nN][aA][mM][eE]/ in h$value )
c$mime$filename = sub(h$value, /^.*[fF][iI][lL][eE][nN][aA][mM][eE]=/, "");
}
event mime_end_entity(c: connection) &priority=-5
{
# This check and the delete below are just to cope with a bug where
# mime_end_entity can be generated multiple times for the same event.
if ( ! c?$mime )
return;
# Don't log anything if there wasn't any content.
if ( c$mime$content_len > 0 )
Log::write(MIME, c$mime);
delete c$mime;
}