This commit prevents most non-Modbus TCP traffic on port 502 to be
reported as Modbus in conn.log as well as in modbus.log.
To do so, we have introduced two &enforce checks in the Modbus
protocol definition that checks that some specific fields of the
(supposedly) Modbus header are compatible with values specified in
the specs.
To ensure non-regression, with this commit we also introduce a
new btest.
Closes#3962
* origin/topic/robin/modbus-events-merge:
adding another trace file to test read and write coil function codes
add/update test file and baseline result
add implementation of bytestring_to_coils for modbusy analyzer
adding a missing field in record ModbusHeaders
add event handlers for modbus
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.
