Makes sense for me. I will change the MQTT dissector to call call_dissector_with_data() only for sparkplug payload.
> Am 29.05.2021 um 09:12 schrieb Anders Broman <a.broma...@gmail.com > <mailto:a.broma...@gmail.com>>: > > Hi, > Shouldn't the caller be calling with the right data type or NULL? So a bug in > the MQTT disector? > Regards > Anders > > > Den lör 29 maj 2021 09:07Uli Heilmeier <ze...@heilmeier.eu > <mailto:ze...@heilmeier.eu>> skrev: > With MR 2706 [1] the MQTT dissector calls now subdissectors with > call_dissector_with_data() [2]. Previously this was call_dissector(). > > With this change the JSON dissector crashes WS with a memory access segfault > (while using MQTT decode topic as option). > This is because for JSON we expect http_message_info_t for data pointer [3]. > MQTT hands over a pointer to a char array (topic_str) for data. > > How do we handle data type for the data parameter pointer? Would it make > sense to compare at least the size of data with the size of > http_message_info_t? > > I don’t know any way to check the data type of a pointer address location. > > Cheers > Uli > > [1]: https://gitlab.com/wireshark/wireshark/-/merge_requests/2706/ > <https://gitlab.com/wireshark/wireshark/-/merge_requests/2706/> > [2]: > https://gitlab.com/wireshark/wireshark/-/merge_requests/2706//diffs#07171e000b3caaabee32ab5dc04a5d28efbaaae3_755_755 > > <https://gitlab.com/wireshark/wireshark/-/merge_requests/2706//diffs#07171e000b3caaabee32ab5dc04a5d28efbaaae3_755_755> > [3]: > https://gitlab.com/wireshark/wireshark/-/blob/master/epan/dissectors/packet-json.c#L221 > > <https://gitlab.com/wireshark/wireshark/-/blob/master/epan/dissectors/packet-json.c#L221> > ___________________________________________________________________________ > Sent via: Wireshark-dev mailing list <wireshark-dev@wireshark.org > <mailto:wireshark-dev@wireshark.org>> > Archives: https://www.wireshark.org/lists/wireshark-dev > <https://www.wireshark.org/lists/wireshark-dev> > Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-dev > <https://www.wireshark.org/mailman/options/wireshark-dev> > mailto:wireshark-dev-requ...@wireshark.org > <mailto:wireshark-dev-requ...@wireshark.org>?subject=unsubscribe > ___________________________________________________________________________ > Sent via: Wireshark-dev mailing list <wireshark-dev@wireshark.org > <mailto:wireshark-dev@wireshark.org>> > Archives: https://www.wireshark.org/lists/wireshark-dev > <https://www.wireshark.org/lists/wireshark-dev> > Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-dev > <https://www.wireshark.org/mailman/options/wireshark-dev> > mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe > <mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe>
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