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Message-ID: <CAADnVQK+LmbmZAJarZkKQD+Ny3c_5aQeMPk3Yj0JbACq3K9MYw@mail.gmail.com>
Date: Mon, 16 Dec 2019 12:33:01 -0800
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: Yonghong Song <yhs@...com>
Cc: Daniel Borkmann <daniel@...earbox.net>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"bpf@...r.kernel.org" <bpf@...r.kernel.org>
Subject: Re: [PATCH bpf] bpf: fix missing prog untrack in release_maps
On Mon, Dec 16, 2019 at 10:52 AM Yonghong Song <yhs@...com> wrote:
>
>
>
> On 12/16/19 8:49 AM, Daniel Borkmann wrote:
> > Commit da765a2f5993 ("bpf: Add poke dependency tracking for prog array
> > maps") wrongly assumed that in case of prog load errors, we're cleaning
> > up all program tracking via bpf_free_used_maps().
> >
> > However, it can happen that we're still at the point where we didn't copy
> > map pointers into the prog's aux section such that env->prog->aux->used_maps
> > is still zero, running into a UAF. In such case, the verifier has similar
> > release_maps() helper that drops references to used maps from its env.
> >
> > Consolidate the release code into __bpf_free_used_maps() and call it from
> > all sides to fix it.
> >
> > Fixes: da765a2f5993 ("bpf: Add poke dependency tracking for prog array maps")
> > Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
>
> Acked-by: Yonghong Song <yhs@...com>
Applied. Thanks
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