Hi, Yes the method is fragile. At the time of development I think it was proposed to pass a struct containing a string and the void pointer where the string could be used as a identifier. But that was voted down. Regards Anders
Den lör 29 maj 2021 09:26Guy Harris <ghar...@sonic.net> skrev: > On May 29, 2021, at 12:12 AM, Anders Broman <a.broma...@gmail.com> wrote: > > > Shouldn't the caller be calling with the right data type or NULL? So a > bug in the MQTT disector? > > How can the MQTT dissector determine what the right data type *is* - > especially given that the dissectors aren't wired in, there's a UAT > preference that lets the user configure it. > > This is where the current mechanism for passing data between dissectors > goes crashing to the ground. > > MQTT passes a topic string, which is just a string, to the dissectors it > calls. > > JSON expects to be passed a pointer to an http_message_info_t. > > JSON registers its non-heuristic dissector by name, and allows it to be > used with Decode As... for UDP ports. > > It might *look* safe if you check the UDP dissector and the dissectors > that use "media_type" and "grpc_message_type", but the "registers its > non-heuristic dissector by name" mean there are no guarantees, given that > another dissector that passes a pointer to something *other* than an > http_message_info_t to dissectors that are specified by name in a UAT. > ___________________________________________________________________________ > Sent via: Wireshark-dev mailing list <wireshark-dev@wireshark.org> > Archives: https://www.wireshark.org/lists/wireshark-dev > Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-dev > mailto:wireshark-dev-requ...@wireshark.org > ?subject=unsubscribe >
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