Wireshark mailing list archives
Re: Calling a dissector: Type for data parameter
From: Anders Broman <a.broman58 () gmail com>
Date: Sat, 29 May 2021 09:12:24 +0200
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 <zeugs () 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/ [2]: 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 ___________________________________________________________________________ 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-request () wireshark org ?subject=unsubscribe
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Current thread:
- Calling a dissector: Type for data parameter Uli Heilmeier (May 29)
- Re: Calling a dissector: Type for data parameter Anders Broman (May 29)
- Re: Calling a dissector: Type for data parameter Uli Heilmeier (May 29)
- Re: Calling a dissector: Type for data parameter Guy Harris (May 29)
- Re: Calling a dissector: Type for data parameter Anders Broman (May 29)
- Re: Calling a dissector: Type for data parameter Graham Bloice (May 30)
- Re: Calling a dissector: Type for data parameter João Valverde via Wireshark-dev (May 30)
- Re: Calling a dissector: Type for data parameter Anders Broman (May 29)