Wireshark-dev: [Wireshark-dev] LIBPCAP offset by one bug when capturing USB

From: "ronnie sahlberg" <ronniesahlberg@xxxxxxxxx>
Date: Sun, 15 Oct 2006 09:10:05 +0000
Paolo.

Could you have a look at the USB memory stick network trace that is
present on  http://wiki.wireshark.org/SampleCaptures?


When I look at these traces it looks to me there is something wrong
with the captured data.


The USB header is fine, as is the SETUP data   but the actual data
blob looks wrong to me, like an offset by one error.


If you look at for example the usb memory stick capture  and the GET
DESCRIPTOR response packets
the response packets always start with a 0x0D byte  and the payload
looks like it is shifted by one.


For example,   see packets 21/22 in the memory stick trace.
Packet 21 is a GET DESCRIPTOR    and packet 22 contains the data.

The data in packet 22 does not make sense.
However  If you remove the initial 0x0D  byte   so that the packet
starts with 0x12  and then add an additional byte at the end,   then
this packet actually makes sense as containing a valid device
descriptor.


Can you have a look at the capture code to see if there is an offset
by one error that would explain these malformed data packets?
And if so,  produce a patch for libpcap?



best regards
ronnie sahlberg



On 10/11/06, Paolo Abeni <paolo.abeni@xxxxxxxx> wrote:
hello,

this patch reflect the changes into usb setup header from current
libpcap cvs.

Paolo



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