netdev - Re: [PATCH bpf] bpf: fix bpf_prog_array_copy_to_user warning from perf event prog query

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Date:   Wed, 14 Feb 2018 09:03:56 -0800
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     ast@...nel.org, yhs@...com, netdev@...r.kernel.org
Subject: Re: [PATCH bpf] bpf: fix bpf_prog_array_copy_to_user warning from
 perf event prog query

On Wed, Feb 14, 2018 at 03:31:00PM +0100, Daniel Borkmann wrote:
> syzkaller tried to perform a prog query in perf_event_query_prog_array()
> where struct perf_event_query_bpf had an ids_len of 1,073,741,353 and
> thus causing a warning due to failed kcalloc() allocation out of the
> bpf_prog_array_copy_to_user() helper. Given we cannot attach more than
> 64 programs to a perf event, there's no point in allowing huge ids_len.
> Therefore, allow a buffer that would fix the maximum number of ids and
> also add a __GFP_NOWARN to the temporary ids buffer.
> 
> Fixes: f371b304f12e ("bpf/tracing: allow user space to query prog array on the same tp")
> Fixes: 0911287ce32b ("bpf: fix bpf_prog_array_copy_to_user() issues")
> Reported-by: syzbot+cab5816b0edbabf598b3@...kaller.appspotmail.com
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>

Applied to bpf tree, Thanks for the quick fix Daniel.