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Date:   Mon, 16 May 2022 18:14:09 -0700
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
To:     Eugene Syromiatnikov <esyr@redhat.com>
Cc:     Jiri Olsa <olsajiri@gmail.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, netdev@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        Shuah Khan <shuah@kernel.org>, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH bpf 1/4] bpf_trace: check size for overflow in
 bpf_kprobe_multi_link_attach
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 <20220516224934.GA5013@asgard.redhat.com>
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On Tue, May 17, 2022 at 12:49:34AM +0200, Eugene Syromiatnikov wrote:
> On Mon, May 16, 2022 at 11:34:45PM +0200, Jiri Olsa wrote:
> > On Mon, May 16, 2022 at 08:27:08PM +0200, Eugene Syromiatnikov wrote:
> > > +	if (check_mul_overflow(cnt, sizeof(*syms), &size))
> > > +		return -EOVERFLOW;
> > 
> > there was an update already:
> > 
> >   0236fec57a15 bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link
> > 
> > so this won't apply anymore, could you please rebase on top of the latest bpf-next/master?
> 
> The issue that this specific check has to go in 4.18, as it covers
> possible out-of-bounds write, I'm not sure how to handle it, have
> a branch where it is merged manually?

As Jiri said, please use bpf-next.