Re: [PATCH 066/190] Revert "bpf: Remove unnecessary assertion on fp_old"

[Alexei Starovoitov]

On Tue, Apr 27, 2021 at 10:59 AM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, Apr 21, 2021 at 02:59:01PM +0200, Greg Kroah-Hartman wrote:
> > This reverts commit 5bf2fc1f9c88397b125d5ec5f65b1ed9300ba59d.
> >
> > Commits from @umn.edu addresses have been found to be submitted in "bad
> > faith" to try to test the kernel community's ability to review "known
> > malicious" changes.  The result of these submissions can be found in a
> > paper published at the 42nd IEEE Symposium on Security and Privacy
> > entitled, "Open Source Insecurity: Stealthily Introducing
> > Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
> > of Minnesota) and Kangjie Lu (University of Minnesota).
> >
> > Because of this, all submissions from this group must be reverted from
> > the kernel tree and will need to be re-reviewed again to determine if
> > they actually are a valid fix.  Until that work is complete, remove this
> > change to ensure that no problems are being introduced into the
> > codebase.
> >
> > Cc: Aditya Pakki <pakki001@xxxxxxx>
> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> > Cc: https
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > ---
> >  kernel/bpf/core.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> > index 75244ecb2389..da29211ea5d8 100644
> > --- a/kernel/bpf/core.c
> > +++ b/kernel/bpf/core.c
> > @@ -230,6 +230,8 @@ struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
> >       struct bpf_prog *fp;
> >       u32 pages;
> >
> > +     BUG_ON(fp_old == NULL);
> > +
> >       size = round_up(size, PAGE_SIZE);
> >       pages = size / PAGE_SIZE;
> >       if (pages <= fp_old->pages)
> > --
> > 2.31.1
> >
>
> The original commit here is correct, I'll drop this revert.

Yes. No need to revert. The original commit removed BUG_ON and it's fine.
Thanks for checking.