Wireshark mailing list archives
Re: how to handle dissecting length encoded strings
From: Chris Maynard <chris.maynard () gtech com>
Date: Mon, 14 Mar 2011 20:18:48 +0000 (UTC)
Jakub Zawadzki <darkjames@...> writes:
hf of type FT_UINT_STRING wouldn't work for you? FT_UINT_STRING A counted string of characters, consisting of a count (represented as an integral value, of width given in the proto_tree_add_item() call) followed immediately by that number of characters
Thanks for pointing that out Jakub. I think that's the best solution. I got caught up looking through the tvb_get_nstringz functions and didn't pay attention to what the dissect_octet_string() function was actually trying to do. But speaking of tvb_get_nstringz ... why does _tvb_get_nstringz only search up to "limit - 1" bytes for the NULL-terminator? If the NULL-terminator is in the limit_th byte, the function will incorrectly return (-1) and the returned string in "buffer" won't be properly NULL-terminated ... unless length remaining is less than bufsize. And speaking of that, why does it NULL-terminate the string if the number of bytes left in the tvb, len, is less than bufsize? If we're doing that, it would seem that for consistency a NULL-terminator should be written even when len >= bufsize. And if that is done, then we wouldn't really need tvb_get_nstringz0, which seems to suffer from a potential buffer overflow problem anyway, where, in the case when len < bufsize from within _tvb_get_nstringz, tvb_get_nstringz0 will still write a NULL-terminator to buffer[bufsize - 1] whenever _tvb_get_nstringz returns (-1), irregardless of whether that was because len < bufsize or not. ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <wireshark-dev () wireshark org> Archives: http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-request () wireshark org?subject=unsubscribe
Current thread:
- how to handle dissecting length encoded strings Fulko Hew (Mar 14)
- Re: how to handle dissecting length encoded strings Chris Maynard (Mar 14)
- Re: how to handle dissecting length encoded strings Chris Maynard (Mar 14)
- Re: how to handle dissecting length encoded strings Fulko Hew (Mar 14)
- Re: how to handle dissecting length encoded strings Chris Maynard (Mar 14)
- Re: how to handle dissecting length encoded strings Jakub Zawadzki (Mar 14)
- Re: how to handle dissecting length encoded strings Chris Maynard (Mar 14)
- Re: how to handle dissecting length encoded strings Chris Maynard (Mar 14)