Instead of these events being generated for invalid byte count values
(they should always be even, not odd), a protocol_violation is raised.
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_respons
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
- Added a test for binpac exception handling -- the generated code
should use "binpac::Exception" and not "Exception" for exception
handling logic to avoid accidental overshadowing by
the analyzer-specific type "binpac::ModbusTCP::Exception", which
could lead to interesting asserts being triggered in binpac.
- Update baseline for the event coverage test -- seems that more
events get generated with working exception handling in the generated
binpac parser code.
- Coverage baseline was giving wrong number of events covered.
* 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.
