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xdp: Prevent kernel-infoleak in xsk_getsockopt()

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xsk_getsockopt() is copying uninitialized stack memory to userspace when
'extra_stats' is 'false'. Fix it. 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.

Fixes: 8aa5a33578e9 ("xsk: Add new statistics")
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/bpf/20200728053604.404631-1-yepeilin.cs@gmail.com
This commit is contained in:
Peilin Ye 2020-07-28 01:36:04 -04:00 committed by Daniel Borkmann
parent f6dfbe31e8
commit 3c4f850e84
1 changed files with 1 additions and 1 deletions
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2
net/xdp/xsk.c
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@ -840,7 +840,7 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname,
switch (optname) {
case XDP_STATISTICS:
{
struct xdp_statistics stats;
struct xdp_statistics stats = {};
bool extra_stats = true;
size_t stats_size;