Re: [PATCH] net/rds: Avoid potential use after free in rds_send_remove_from_sock

[Krzysztof Kozlowski]

On Tue, 20 Apr 2021 at 11:13, Leon Romanovsky <leon@xxxxxxxxxx> wrote:
>
> On Tue, Apr 20, 2021 at 12:09:06PM +0300, Leon Romanovsky wrote:
> > On Tue, Apr 06, 2021 at 07:09:12PM -0500, Aditya Pakki wrote:
> > > In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource
> > > is freed and later under spinlock, causing potential use-after-free.
> > > Set the free pointer to NULL to avoid undefined behavior.
> > >
> > > Signed-off-by: Aditya Pakki <pakki001@xxxxxxx>
> > > ---
> > >  net/rds/message.c | 1 +
> > >  net/rds/send.c    | 2 +-
> > >  2 files changed, 2 insertions(+), 1 deletion(-)
> >
> > Dave, Jakub
> >
> > Please revert this patch, given responses from Eric and Al together
> > with this response from Greg here https://lore.kernel.org/lkml/YH5/i7OvsjSmqADv@xxxxxxxxx
>
> https://lore.kernel.org/lkml/YH5%2Fi7OvsjSmqADv@xxxxxxxxx/
>
> >
> > BTW, I looked on the rds code too and agree with Eric, this patch
> > is a total garbage.

When reverting, consider giving credits to Kees/Coverity as he pointed
out after testing linux-next that this is bogus:
https://lore.kernel.org/linux-next/202104081640.1A09A99900@keescook/


Best regards,
Krzysztof