[Linux-kernel-mentees] [PATCH net v2] xdp: Prevent kernel-infoleak in xsk_getsockopt()

Daniel Borkmann daniel at iogearbox.net
Tue Jul 28 10:53:59 UTC 2020

On 7/28/20 7:36 AM, Peilin Ye wrote:
> xsk_getsockopt() is copying uninitialized stack memory to userspace when
> `extra_stats` is `false`. Fix it.
> Fixes: 8aa5a33578e9 ("xsk: Add new statistics")
> Suggested-by: Dan Carpenter <dan.carpenter at oracle.com>
> Signed-off-by: Peilin Ye <yepeilin.cs at gmail.com>
> ---
> Doing `= {};` is sufficient since currently `struct xdp_statistics` is
> defined as follows:
> struct xdp_statistics {
> 	__u64 rx_dropped;
> 	__u64 rx_invalid_descs;
> 	__u64 tx_invalid_descs;
> 	__u64 rx_ring_full;
> 	__u64 rx_fill_ring_empty_descs;
> 	__u64 tx_ring_empty_descs;
> };
> When being copied to the userspace, `stats` will not contain any
> uninitialized "holes" between struct fields.

I've added above explanation to the commit log since it's useful reasoning for later
on 'why' something has been done a certain way. Applied, thanks Peilin!

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