[PATCH] scan: Solve the problem of garbled characters in the scanned ssid

王鑫鹏 wangxinpeng at uniontech.com
Fri Oct 29 00:18:14 PDT 2021

> > > On Fri, 2021-10-29 at 14:40 +0800, xinpeng.wang wrote:
> > > Using Netgear WN11V2 usb wireless network card, it is easy to have
> > > garbled characters i
> > > n the scanned ssid. This is because the driver sends the problem
> > > packets to wpa through
> > > netlink. These packets are only partly seen through wireshark, but
> > > the missing parts when
> > > sent to wpa are some random values, which may cause the read ssid
> > > to be garbled.
> > > In the update scan res, check whether the sum of the length of
> > > each ie in ies is the same
> > > as ie_len. If it is not the same, it is considered to be abnormal
> > > packet and discard it.
> > > Seems like something the *driver* should do?
> >  thank you for your reply.
> > I think the driver should be able to ensure that what is passed to wpa
> > is correct, but wpa 
> > should also be able to filter these packets and not be affected by
> > these abnormal packets.

> I'm not sure I agree. If we wanted to put workarounds for all hardware
> bugs into wpa_supplicant, that'd probably end up quite a mess. Such
> things are better handled by the specific driver.

> Clearly wpa_supplicant needs to ensure its own consistency isn't
> damaged, e.g. that it doesn't crash on malformed (perhaps maliciously
> so) frames, but as long as the frame is just garbage, IMHO the driver
> should do such things.

> Note also that in this particular instance, I believe you're now
> dropping beacon frames that don't have completely well-formed elements,
> which is very well known to cause problems.

 thank you for your reply.
I will find a way to solve this problem from the driver.


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