Re: [PATCH] net: davicom: fix UAF in dm9000_drv_remove

[Chenyuan Yang]

Hello,

Thanks for pointing this out!

On Mon, Jan 20, 2025 at 11:33 PM Uwe Kleine-König
<u.kleine-koenig@xxxxxxxxxxxx> wrote:
>
> Hello,
>
> On Mon, Jan 20, 2025 at 04:25:57PM -0600, Chenyuan Yang wrote:
> > dm is netdev private data and it cannot be
> > used after free_netdev() call. Using adpt after free_netdev()
>
> What is adpt?

This should be "dm".

> > can cause UAF bug. Fix it by moving free_netdev() at the end of the
> > function.
>
> "can cause"? Doesn't that trigger reliable?
>
> How did you find that issue? Did this actually trigger for you, or is it
> a static checker that found it? Please mention that in the commit log.

This is detected by our static checker. Thus, we don't have a
test-case to trigger it stably.
Basically, it has the buggy pattern as the commit mentioned below.

> > This is similar to the issue fixed in commit
> > ad297cd2db8953e2202970e9504cab247b6c7cb4 ("net: qcom/emac: fix UAF in emac_remove").
>
> Please shorten the commit id, typically to 12 chars as you did in the
> Fixes line below.

Sure! Should I send a Patch v2 for this commit?

> > Fixes: cf9e60aa69ae ("net: davicom: Fix regulator not turned off on driver removal")
> > Signed-off-by: Chenyuan Yang <chenyuan0y@xxxxxxxxx>
>
> Best regards
> Uwe

Best,
Chenyuan