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References: <20220602224754.602074-1-namhyung@kernel.org> <YpojK0iaPofkAzd4@google.com>
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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Fri, 24 Jun 2022 10:30:57 -0700
Message-ID: <CAM9d7cjGiBEW0jfoc6iaXnHGhvQZVM-aRke=kdgJEbfSPAt+ug@mail.gmail.com>
Subject: Re: [PATCH] perf/core: Call LSM hook after copying perf_event_attr
To:     Joel Fernandes <joel@joelfernandes.org>,
        Peter Zijlstra <peterz@infradead.org>
Cc:     Ingo Molnar <mingo@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Jiri Olsa <jolsa@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Stephane Eranian <eranian@google.com>,
        Andi Kleen <ak@linux.intel.com>,
        Ian Rogers <irogers@google.com>,
        James Morris <jmorris@namei.org>
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Hi Peter,

On Fri, Jun 3, 2022 at 8:05 AM Joel Fernandes <joel@joelfernandes.org> wrote:
>
> On Thu, Jun 02, 2022 at 03:47:54PM -0700, Namhyung Kim wrote:
> > It passes the attr struct to the security_perf_event_open() but it's
> > not initialized yet.
> >
> > Fixes: da97e18458fb ("perf_event: Add support for LSM and SELinux checks")
> > Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > ---
> >  kernel/events/core.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/kernel/events/core.c b/kernel/events/core.c
> > index 7858bafffa9d..e035545f624f 100644
> > --- a/kernel/events/core.c
> > +++ b/kernel/events/core.c
> > @@ -12033,12 +12033,12 @@ SYSCALL_DEFINE5(perf_event_open,
> >       if (flags & ~PERF_FLAG_ALL)
> >               return -EINVAL;
> >
> > -     /* Do we allow access to perf_event_open(2) ? */
> > -     err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
> > +     err = perf_copy_attr(attr_uptr, &attr);
> >       if (err)
> >               return err;
> >
> > -     err = perf_copy_attr(attr_uptr, &attr);
> > +     /* Do we allow access to perf_event_open(2) ? */
> > +     err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
>
> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>

Any chance you can pick this up?

Thanks,
Namhyung