Wireshark · Wireshark-dev: Re: [Wireshark-dev] DISSECTOR_ASSERT_NOT_REACHED in WLCCP decode...

[Jeff Morriss <jeff.morriss@xxxxxxxxxxx>]

Kevin A. Noll wrote:
> I think I've figured out that I am getting the DISSECTOR_ASSERT because of
> something related to the dissector being near the end of the tvbuff.
> However, I've tried several things to try to debug exactly what occuring,
> but I can't get the error to go away.
>
> This error occurs when I am reading a structure from tvb with
> proto_tree_add_item:
>
> guint16 mic_length=0;
>
> mic_length = tvb_get_ntohs(tvb, tlv_offset);
> tlv_offset += 2;
>
> proto_tree_add_item(tlv_tree, hf_wlccp_mic_value, tvb, tlv_offset,
> mic_length, FALSE);
>
> Where hf_wlccp_mic_value is defined as:
>
> { &hf_wlccp_mic_value, 
>   {"MIC Value", "wlccp.mic_value", 
>     FT_UINT_BYTES, BASE_DEC, NULL, 0, 
>    "MIC value", HFILL }
> }
>
>
> I get the error even if I set the value of mic_length to something I know
> does not overrun the end of tvb.
>
> I would greatly appreciate any suggestions on how to fix my error.

Any chance of getting a core and thus a backtrace?  That might be faster.

You might also try changing BASE_DEC to BASE_HEX: I'm not sure 
UINT_BYTES can be displayed in decimal (bug 1539 talks about a vaguely 
similar issue).