For modbus message types that include variable amount of register values
(uint16[]), setting a &length attribute without an explicit array size
could trigger a parsing assertion since it allows for the "element" data
pointer to travel past the "end of data" (e.g. when &length is odd).
This is changed to now give both an array size and &length to earlier
terminate the parsing of elements before the assert is checked and
so a single out-of-bound check can be done for the entire array
(leaving off &length causes an out-of-bound check for each element).
Added another parameter to modbus events that carry register arrays to
the script-layer which indicates the associated byte count from the
message (allowing for invalid values to be detected):
modbus_read_holding_registers_response
modbus_read_input_registers_response
modbus_write_multiple_registers_request
modbus_read_write_multiple_registers_request
modbus_read_write_multiple_registers_response
modbus_read_fifo_queue_response
- There are still some broken events in the modbus analyzer because
I don't have traffic to test with (coil and record related events primarily).
- There are a few example scripts in policy/protocols/modbus
- Renamed many data structures to align with most recent standard.
- Reworked modbus events to make them more canonically "Bro".
- Converted the Modbus analyzer to a simpler style for easier maintenance.
- Modbus coil related events still don't work (I haven't finished the
function for converting the data structures).
- Modbus file record events remain incomplete.
* origin/topic/dina/modbus:
put some make-up on Modbus analyser
Modbus analyser, added support: FC=20,21
Modbus analyzer,added support: FC=1,2,15,24
Modbus analyzer, current support: FC=3,4,5,6,7,16,22,23
I cleaned up the code a bit, mainly layout style.
I did not include the *.bro scripts for now, but a test script
../testing/btest/scripts/base/protocols/modbus/events.bro that prints
out the value for each event.
Merged the Modbus traces from the ics repository into a single trace
as input for the test. They currently trigger 20 of the 34 events.
Addresses #870.
