zeek/scripts/base/protocols/ntlm/main.zeek
Benjamin Bannier d5fd29edcd Prefer explicit construction to coercion in record initialization
While we support initializing records via coercion from an expression
list, e.g.,

    local x: X = [$x1=1, $x2=2];

this can sometimes obscure the code to readers, e.g., when assigning to
value declared and typed elsewhere. The language runtime has a similar
overhead since instead of just constructing a known type it needs to
check at runtime that the coercion from the expression list is valid;
this can be slower than just writing the readible code in the first
place, see #4559.

With this patch we use explicit construction, e.g.,

    local x = X($x1=1, $x2=2);
2025-07-11 16:28:37 -07:00

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@load base/protocols/conn/removal-hooks
module NTLM;
export {
redef enum Log::ID += { LOG };
global log_policy: Log::PolicyHook;
type Info: record {
## Timestamp for when the event happened.
ts : time &log;
## Unique ID for the connection.
uid : string &log;
## The connection's 4-tuple of endpoint addresses/ports.
id : conn_id &log;
## Username given by the client.
username : string &log &optional;
## Hostname given by the client.
hostname : string &log &optional;
## Domainname given by the client.
domainname : string &log &optional;
## NetBIOS name given by the server in a CHALLENGE.
server_nb_computer_name: string &log &optional;
## DNS name given by the server in a CHALLENGE.
server_dns_computer_name: string &log &optional;
## Tree name given by the server in a CHALLENGE.
server_tree_name: string &log &optional;
## Indicate whether or not the authentication was successful.
success : bool &log &optional;
## Internally used field to indicate if the login attempt
## has already been logged.
done: bool &default=F;
};
## NTLM finalization hook. Remaining NTLM info may get logged when it's called.
global finalize_ntlm: Conn::RemovalHook;
}
redef DPD::ignore_violations += { Analyzer::ANALYZER_NTLM };
redef record connection += {
ntlm: Info &optional;
};
event zeek_init() &priority=5
{
Log::create_stream(NTLM::LOG, Log::Stream($columns=Info, $path="ntlm", $policy=log_policy));
}
function set_session(c: connection)
{
if ( ! c?$ntlm )
{
c$ntlm = NTLM::Info($ts=network_time(), $uid=c$uid, $id=c$id);
Conn::register_removal_hook(c, finalize_ntlm);
}
}
event ntlm_negotiate(c: connection, request: NTLM::Negotiate) &priority=5
{
set_session(c);
}
event ntlm_challenge(c: connection, challenge: NTLM::Challenge) &priority=5
{
set_session(c);
if ( challenge?$target_info )
{
local ti = challenge$target_info;
if ( ti?$nb_computer_name )
c$ntlm$server_nb_computer_name = ti$nb_computer_name;
if ( ti?$dns_computer_name )
c$ntlm$server_dns_computer_name = ti$dns_computer_name;
if ( ti?$dns_tree_name )
c$ntlm$server_tree_name = ti$dns_tree_name;
}
}
event ntlm_authenticate(c: connection, request: NTLM::Authenticate) &priority=5
{
set_session(c);
if ( request?$domain_name )
c$ntlm$domainname = request$domain_name;
if ( request?$workstation )
c$ntlm$hostname = request$workstation;
if ( request?$user_name )
c$ntlm$username = request$user_name;
}
event gssapi_neg_result(c: connection, state: count) &priority=3
{
# Ignore "incomplete" replies (state==1)
if ( c?$ntlm && state != 1 )
c$ntlm$success = (state == 0);
}
event gssapi_neg_result(c: connection, state: count) &priority=-3
{
if ( c?$ntlm && ! c$ntlm$done )
{
# Only write if success is actually set to something...
if ( c$ntlm?$success )
{
Log::write(NTLM::LOG, c$ntlm);
c$ntlm$done = T;
}
}
}
hook finalize_ntlm(c: connection)
{
if ( c?$ntlm && ! c$ntlm$done )
{
Log::write(NTLM::LOG, c$ntlm);
}
}