Re: [PATCH net-next] ptr_ring: fix integer overflow

[David Miller]

From: Jason Wang <jasowang@xxxxxxxxxx>
Date: Thu, 25 Jan 2018 15:31:42 +0800

> We try to allocate one more entry for lockless peeking. The adding
> operation may overflow which causes zero to be passed to kmalloc().
> In this case, it returns ZERO_SIZE_PTR without any notice by ptr
> ring. Try to do producing or consuming on such ring will lead NULL
> dereference. Fix this detect and fail early.
> 
> Fixes: bcecb4bbf88a ("net: ptr_ring: otherwise safe empty checks can overrun array bounds")
> Reported-by: syzbot+87678bcf753b44c39b67@xxxxxxxxxxxxxxxxxxxxxxxxx
> Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>

I'm dropping this because I am to understand that Michael Tsirkin's patch
series covers this issue.

Let me know if I still need to apply this.

Thanks.