Comment # 9
on bug 8635
from Peter Van Eynde
Hello Jörg,
(In reply to comment #8)
> So looking into the current version with some more time:
> - I already asked why you changed some variables from FT_IPv4 to FT_UINT32.
Sorry I must have missed that. Where did you ask this?
> While I now understand that these values are printed via
> wccp_fmt_ipadddress, this is not equivalent as we loose the special features
> that we get by using FT_IPv4 and FT_IPv6. If would be good to add "normal"
> addresses via the correct FT_IPvX types and only print strings when there is
> a special case (error).
I understand and prefer that way in fact. However IPv6 support in WCCP is done
by adding a new section which translates UNIT32 indices into IP addresses.
See http://tools.ietf.org/html/draft-mclaggan-wccp-v2rev1-00#page-38
So the binary value is either FT_IPv4 if there is no address table component,
or it can be index which we can translate to a IPv4 or IPv6 address using the
address table component.
I have found no clean way to implement this besides the custom formatter, what
better way is there to implement this?
> - In find_wccp_address_table: I'm not sure (due to lack of knowledge of the
> c standard) that there can't be an integer overflow in the while loop.
I can see your concern, at the moment I so:
..
guint16 item_length, length;
while (length >= 4) {
item_length = ...
/* check if we _can_ advance */
if (length < (item_length+4))
return;
offset = offset + item_length + 4;
length = length - item_length - 4;
}
your concern is that if for example length is 4 and item_length is 0xFFFFFFFE
that (item_length + 4) is 3. 4 > 3 so length becomes 4 - 0xFFFFFFFE - 4 -> 2.
As far as I can see the loop should be overflow free.
> Anyway doing an extra check of the item_length when read from the packet
> would make sense.
Checking if item_length <= tvb_length_remaining(tvb,offset) ?
> - NOTE_EATEN_LENGTH is probably a tpyo
Sorry can't see this, what should it be?
Thanks for the review! Peter
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