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From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>, sameehj@amazon.com
Cc: Jesper Dangaard Brouer <brouer@redhat.com>,
	netdev@vger.kernel.org, bpf@vger.kernel.org, zorik@amazon.com,
	akiyano@amazon.com, gtzalik@amazon.com,
	Daniel Borkmann <borkmann@iogearbox.net>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Alexander Duyck <alexander.duyck@gmail.com>,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
	David Ahern <dsahern@gmail.com>,
	Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	Ilias Apalodimas <ilias.apalodimas@linaro.org>,
	Lorenzo Bianconi <lorenzo@kernel.org>
Subject: Re: [PATCH RFC v1 09/15] xdp: clear grow memory in bpf_xdp_adjust_tail()
Date: Wed, 18 Mar 2020 10:15:38 +0100	[thread overview]
Message-ID: <87v9n2koqt.fsf@toke.dk> (raw)
In-Reply-To: <158446619342.702578.1522482431365026926.stgit@firesoul>

Jesper Dangaard Brouer <brouer@redhat.com> writes:

> To reviewers: Need some opinions if this is needed?
>
> (TODO: Squash patch)
> ---
>  net/core/filter.c |    6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 0ceddee0c678..669f29992177 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -3432,6 +3432,12 @@ BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset)
>  	if (unlikely(data_end < xdp->data + ETH_HLEN))
>  		return -EINVAL;
>  
> +	// XXX: To reviewers: How paranoid are we? Do we really need to
> +	/* clear memory area on grow, as in-theory can contain uninit kmem */
> +	if (offset > 0) {
> +		memset(xdp->data_end, 0, offset);
> +	}

This memory will usually be recycled through page_pool or equivalent,
right? So couldn't we clear the pages when they are first allocated?
That way, the only data that would be left there would be packet data
from previous packets...

-Toke


  parent reply	other threads:[~2020-03-18  9:15 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-17 17:29 [PATCH RFC v1 00/15] XDP extend with knowledge of frame size Jesper Dangaard Brouer
2020-03-17 17:29 ` [PATCH RFC v1 01/15] xdp: add frame size to xdp_buff Jesper Dangaard Brouer
2020-03-17 20:42   ` Jakub Kicinski
2020-03-18  6:58     ` Jesper Dangaard Brouer
2020-03-17 17:29 ` [PATCH RFC v1 02/15] mvneta: add XDP frame size to driver Jesper Dangaard Brouer
2020-03-17 17:29 ` [PATCH RFC v1 03/15] bnxt: " Jesper Dangaard Brouer
2020-03-20 19:22   ` Andy Gospodarek
2020-03-23 14:18   ` Andy Gospodarek
2020-03-23 14:44     ` Jesper Dangaard Brouer
2020-03-17 17:29 ` [PATCH RFC v1 04/15] ixgbe: fix XDP redirect on archs with PAGE_SIZE above 4K Jesper Dangaard Brouer
2020-03-17 17:29 ` [PATCH RFC v1 05/15] ixgbe: add XDP frame size to driver Jesper Dangaard Brouer
2020-03-18 20:03   ` Maciej Fijalkowski
2020-03-18 21:23     ` Alexander Duyck
2020-03-20 21:44       ` Jesper Dangaard Brouer
2020-03-20 22:37         ` Alexander Duyck
2020-03-17 17:29 ` [PATCH RFC v1 06/15] sfc: fix XDP-redirect in this driver Jesper Dangaard Brouer
2020-03-17 17:29 ` [PATCH RFC v1 07/15] sfc: add XDP frame size Jesper Dangaard Brouer
2020-03-17 17:29 ` [PATCH RFC v1 08/15] xdp: allow bpf_xdp_adjust_tail() to grow packet size Jesper Dangaard Brouer
2020-03-17 17:29 ` [PATCH RFC v1 09/15] xdp: clear grow memory in bpf_xdp_adjust_tail() Jesper Dangaard Brouer
2020-03-17 20:38   ` Jakub Kicinski
2020-03-18  9:15   ` Toke Høiland-Jørgensen [this message]
2020-03-18 10:25     ` Jesper Dangaard Brouer
2020-03-19  5:35       ` Alexei Starovoitov
2020-03-17 17:29 ` [PATCH RFC v1 10/15] net: XDP-generic determining XDP frame size Jesper Dangaard Brouer
2020-03-17 17:30 ` [PATCH RFC v1 11/15] xdp: xdp_frame add member frame_sz and handle in convert_to_xdp_frame Jesper Dangaard Brouer
2020-03-17 17:30 ` [PATCH RFC v1 12/15] xdp: cpumap redirect use frame_sz and increase skb_tailroom Jesper Dangaard Brouer
2020-03-17 17:30 ` [PATCH RFC v1 13/15] tun: add XDP frame size Jesper Dangaard Brouer
2020-03-17 17:30 ` [PATCH RFC v1 14/15] veth: xdp using frame_sz in veth driver Jesper Dangaard Brouer
2020-03-17 17:30 ` [PATCH RFC v1 15/15] dpaa2-eth: add XDP frame size Jesper Dangaard Brouer

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