[PATCH] mac80211_hwsim: correctly handle zero length frames

Anirudh Rayabharam mail at anirudhrb.com
Wed Jun 23 07:26:20 UTC 2021


On Fri, Jun 18, 2021 at 11:36:16AM +0200, Johannes Berg wrote:
> On Thu, 2021-06-10 at 21:49 +0530, Anirudh Rayabharam wrote:
> > syzbot, using KMSAN, has reported an uninit-value access in
> > hwsim_cloned_frame_received_nl(). This is happening because frame_data_len
> > is 0. The code doesn't detect this case and blindly tries to read the
> > frame's header.
> > 
> > Fix this by bailing out in case frame_data_len is 0.
> 
> This really seems quite pointless - you should bail out if the frame is
> too short for what we need to do, not just when it's 0.

That makes sense. Do you happen to know what the min length of a valid
frame is? There doesn't seem to be constant defined for that already.

	- Anirudh

> 
> johannes
> 


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