netdev - Re: [PATCH bpf] bpf: fix inner map masking to prevent oob under speculation

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Message-ID: <20190118232540.efigxptqyrpdk77s@ast-mbp.dhcp.thefacebook.com>
Date:   Fri, 18 Jan 2019 15:25:41 -0800
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     ast@...nel.org, netdev@...r.kernel.org
Subject: Re: [PATCH bpf] bpf: fix inner map masking to prevent oob under
 speculation

On Thu, Jan 17, 2019 at 04:34:45PM +0100, Daniel Borkmann wrote:
> During review I noticed that inner meta map setup for map in
> map is buggy in that it does not propagate all needed data
> from the reference map which the verifier is later accessing.
> 
> In particular one such case is index masking to prevent out of
> bounds access under speculative execution due to missing the
> map's unpriv_array/index_mask field propagation. Fix this such
> that the verifier is generating the correct code for inlined
> lookups in case of unpriviledged use.
> 
> 
> Fixes: b2157399cc98 ("bpf: prevent out-of-bounds speculation")
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>

Applied, Thanks