On Fri, Jul 31, 2020 at 02:07:42AM +0200, Daniel Borkmann wrote:
> On 7/30/20 6:13 PM, Christian Brauner wrote:
> > On Thu, Jul 30, 2020 at 06:09:00PM +0200, Christoph Hellwig wrote:
> > > __bpfilter_process_sockopt never initialized the pos variable passed to
> > > the pipe write. This has been mostly harmless in the past as pipes
> > > ignore the offset, but the switch to kernel_write no verified the
> >
> > s/no/now/
> >
> > > position, which can lead to a failure depending on the exact stack
> > > initialization patter. Initialize the variable to zero to make
> >
> > s/patter/pattern/
> >
> > > rw_verify_area happy.
> > >
> > > Fixes: 6955a76fbcd5 ("bpfilter: switch to kernel_write")
> > > Reported-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
> > > Reported-by: Rodrigo Madera <rodrigo.madera@xxxxxxxxx>
> > > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> > > Tested-by: Rodrigo Madera <rodrigo.madera@xxxxxxxxx>
> > > ---
> >
> > Thanks for tracking this down, Christoph! This fixes the logging issue
> > for me.
> > Tested-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
> > Reviewed-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
>
> Applied to bpf & fixed up the typos in the commit msg, thanks everyone!
Daniel,
why is it necessary in bpf tree?
I fixed it already in bpf-next in commit a4fa458950b4 ("bpfilter: Initialize pos variable")
two weeks ago...
